EX-99.(a)(1)(A)

THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 9:00 A.M., NEW YORK CITY TIME, ON APRIL 18, 2014, UNLESS THE OFFER IS EXTENDED (SUCH DATE AND TIME, AS IT MAY BE SO EXTENDED, THE “EXPIRATION DATE”), UNLESS EARLIER TERMINATED BY THE PURCHASER.

MA Acquisition Inc., a Delaware corporation (the “Purchaser”) and a wholly owned subsidiary of Minerals Technologies Inc., a Delaware corporation (“MTI”), is offering to purchase all outstanding shares of common stock, par value $0.01 per share (each, a “Share”), of AMCOL International Corporation, a Delaware corporation (“AMCOL”), at a price of $45.75 per Share, net to the seller in cash, without interest (the “Offer Price”) and less any applicable withholding tax, upon the terms and subject to the conditions set forth in this Offer to Purchase (as it may be amended or supplemented, this “Offer to Purchase”) and in the related Letter of Transmittal (as it may be amended or supplemented, the “Letter of Transmittal” and, together with this Offer to Purchase, the “Offer”). The Offer is being made for all outstanding Shares, and not for options to purchase Shares or other equity awards. The Offer is being made pursuant to an Agreement and Plan of Merger (as it may be amended or supplemented, the “Merger Agreement”), dated as of March 10, 2014, by and among AMCOL, MTI and the Purchaser, pursuant to which, after the completion of the Offer and the satisfaction or waiver of certain conditions, the Purchaser will be merged with and into AMCOL, with AMCOL continuing as the surviving corporation and a wholly owned subsidiary of MTI (the “Merger”). At the effective time of the Merger (the “Effective Time”), each Share issued and outstanding immediately prior to the Effective Time, other than (i) Shares held by AMCOL as treasury stock or owned by MTI or the Purchaser, all of which will be canceled and shall cease to exist, and (ii) Shares owned by stockholders of AMCOL who or which is entitled to demand, and who properly demands, appraisal rights pursuant to Section 262 of the General Corporation Law of the State of Delaware (the “DGCL”), will be converted into the right to receive an amount in cash equal to the Offer Price, less any applicable withholding tax.

THE AMCOL BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS THAT AMCOL’S STOCKHOLDERS ACCEPT THE OFFER AND TENDER THEIR SHARES PURSUANT TO THE OFFER.

AMCOL’s board of directors (the “AMCOL Board”) has unanimously (i) adopted and declared the advisability of the Merger Agreement, the Offer, the Merger and the other transactions contemplated by the Merger Agreement (the Offer, the Merger and the other transactions contemplated by the Merger Agreement, collectively, the “Transactions”), (ii) declared that it is in the best interests of AMCOL and the stockholders of AMCOL (other than MTI and its subsidiaries) that AMCOL enter into the Merger Agreement and consummate the Transactions and that the stockholders of AMCOL tender their Shares pursuant to the Offer, (iii) declared that the terms of the Offer and the Merger are fair to AMCOL and the stockholders of AMCOL (other than MTI and its subsidiaries) and (iv) resolved to recommend that the stockholders of AMCOL accept the Offer and tender their Shares pursuant to the Offer. As soon as practicable following the consummation of the Offer and subject to the satisfaction or waiver of the remaining conditions set forth in the Merger Agreement, MTI, the Purchaser and AMCOL will cause the Merger to become effective without a meeting of the stockholders of AMCOL to adopt the Merger Agreement or any other action by the stockholders of AMCOL in accordance with Section 251(h) of the DGCL.

There is no financing condition to the Offer. The Offer is subject to the satisfaction of the “Minimum Condition,” the “Regulatory Condition” and the other conditions described in Section 15—“Conditions of the Offer.” A summary of the principal terms of the Offer appears on pages 3 through 11 of this Offer to Purchase. You should read this entire document carefully before deciding whether to tender your Shares pursuant to the Offer.

Any stockholder of AMCOL wishing to tender Shares pursuant to the Offer must (i) complete and sign the Letter of Transmittal that accompanies this Offer to Purchase in accordance with the instructions therein and mail or deliver the Letter of Transmittal and all other required documents to American Stock Transfer & Trust Company, LLC, the depositary for the Offer (the “Depositary”) together with certificates representing the Shares tendered or tender your Shares by book-entry transfer by following the procedures described in Section 3—“Procedures for Accepting the Offer and Tendering Shares” or (ii) request such stockholder’s broker, dealer, commercial bank, trust company or other nominee to effect the transaction for the stockholder. A stockholder whose Shares are registered in the name of a broker, dealer, commercial bank, trust company or other nominee must contact such person if such stockholder wishes to tender such Shares.

Any stockholder of AMCOL who wishes to tender Shares and cannot deliver certificates representing such Shares and all other required documents to the Depositary on or prior to the Expiration Date (as defined in the Introduction to this Offer to Purchase) or who cannot comply with the procedures for book-entry transfer on a timely basis, may tender such Shares pursuant to the guaranteed delivery procedure described in Section 3—“Procedures for Accepting the Offer and Tendering Shares.”

Questions and requests for assistance may be directed to the Information Agent (as defined herein and identified below) or the Dealer Manager (as defined herein and identified below) at their respective addresses and telephone numbers set forth below. Additional copies of this Offer to Purchase, the Letter of Transmittal, the Notice of Guaranteed Delivery and other related materials may also be obtained from the Information Agent. Stockholders may also contact their broker, dealer, commercial bank, trust company or other nominee for copies of these documents.

The Letter of Transmittal, certificates for Shares and any other required documents must reach the Depositary prior to the Expiration Date, unless the guaranteed delivery procedures described in Section 3—“Procedures for Accepting the Offer and Tendering Shares” are followed.

This transaction has not been approved or disapproved by the U.S. Securities and Exchange Commission (the “SEC”) or any state securities commission, nor has the SEC or any state securities commission passed upon the fairness or merits of this transaction or upon the accuracy or adequacy of the information contained in this Offer to Purchase or the Letter of Transmittal. Any representation to the contrary is unlawful.

THIS OFFER TO PURCHASE AND THE LETTER OF TRANSMITTAL CONTAIN IMPORTANT INFORMATION, AND YOU SHOULD READ BOTH CAREFULLY AND IN THEIR ENTIRETY BEFORE MAKING A DECISION WITH RESPECT TO THE OFFER.

MA Acquisition Inc., a wholly owned subsidiary of Minerals Technologies Inc., is offering to purchase all outstanding Shares at a price of $45.75 per Share, net to the seller in cash, without interest and less any applicable withholding tax, upon the terms and subject to the conditions set forth in the Merger Agreement, this Offer to Purchase and the accompanying Letter of Transmittal. The following are some questions you, as a stockholder of AMCOL, may have about the Offer and answers to those questions. This summary term sheet highlights selected information from this Offer to Purchase, and may not contain all of the information that is important to you and is qualified in its entirety by the more detailed descriptions and explanations contained in this Offer to Purchase and the accompanying Letter of Transmittal. To better understand the Offer and for a complete description of the legal terms of the Offer, you should read this Offer to Purchase and the accompanying Letter of Transmittal carefully and in their entirety. Questions or requests for assistance may be directed to the Information Agent or the Dealer Manager at their respective addresses and telephone numbers set forth on the back cover of this Offer to Purchase. Unless otherwise indicated in this Offer to Purchase or the context otherwise requires, all references in this Offer to Purchase to “Purchaser,” “we,” “our,” or “us” refer to MA Acquisition Inc.

We are MA Acquisition Inc., a Delaware corporation recently formed for the purpose of making this Offer. We are a wholly owned subsidiary of Minerals Technologies Inc. or “MTI,” a Delaware corporation. We were organized in connection with the Offer and have not carried on any activities other than entering into the Merger Agreement and activities in connection with the Offer. Upon the terms and subject to the conditions set forth in this Offer to Purchase, we will purchase all Shares validly tendered and not validly withdrawn pursuant to the Offer. See Section 9—“Certain Information Concerning MTI and the Purchaser.”

MTI is a resource- and technology-based company that develops, produces and markets worldwide a broad range of specialty mineral, mineral-based and synthetic mineral products and supporting systems and services. MTI has two reportable segments: Specialty Minerals and Refractories. The Specialty Minerals segment produces and sells the synthetic mineral product precipitated calcium carbonate and processed mineral product quicklime, and mines mineral ores then processes and sells natural mineral products, primarily limestone and talc. This segment’s products are used principally in the paper, building materials, paint and coatings, glass, ceramic, polymer, food, automotive and pharmaceutical industries. The Refractories segment produces and markets monolithic and shaped refractory materials and specialty products, services and application and measurement equipment, and calcium metal and metallurgical wire products. The Refractories segment products are primarily used in high-temperature applications in the steel, non-ferrous metal and glass industries.

MTI maintains a research and development focus. MTI’s research and development capability for developing and introducing technologically advanced new products has enabled MTI to anticipate and satisfy changing customer requirements, creating market opportunities through new product development and product application innovations. MTI recorded sales of $1.02 billion in 2013. See Section 9—“Certain Information Concerning MTI and the Purchaser.”

Pursuant to the Merger Agreement, the Purchaser has agreed to, and MTI has agreed to cause the Purchaser to, upon the terms and subject to the conditions in this Offer to Purchase and the accompanying Letter of Transmittal, accept and pay for Shares validly tendered and not validly withdrawn pursuant to the Offer.

We are seeking to purchase all of the issued and outstanding Shares, upon the terms and subject to the conditions set forth in this Offer to Purchase and the Letter of Transmittal. See the “Introduction” to this Offer to Purchase and Section 1—“Terms of the Offer.”

How does the Offer relate to the announced transaction between AMCOL and Imerys?

On February 12, 2014, AMCOL and Imerys SA, a corporation organized under the laws of France (“Imerys”), announced that they had entered into an agreement and plan of merger pursuant to which Imerys would acquire AMCOL through its wholly owned subsidiary Imerys Minerals Delaware, Inc. Under the terms of the original agreement between AMCOL and Imerys, for each Share, AMCOL stockholders would have received $41.00 in cash. On February 26, 2014, AMCOL and Imerys amended their agreement such that, for each Share, AMCOL stockholders would have received $42.75 in cash, and on March 4, 2014, AMCOL and Imerys further amended their agreement such that, for each Share, AMCOL stockholders would have received $45.25 in cash. On March 10, 2014, AMCOL terminated its agreement with Imerys to enter into the Merger Agreement with MTI, which contemplates the Offer Price of $45.75 per Share in cash. See Section 11—“Background of the Offer; Past Contacts or Negotiations with AMCOL.”

How much are you offering to pay for my Shares and what is the form of payment?

We are offering to pay $45.75 per Share, net to you, in cash, without interest thereon and less any applicable withholding taxes, upon the terms and subject to the conditions contained in this Offer to Purchase and the accompanying Letter of Transmittal.

Will I have to pay any fees or commissions if I tender my Shares pursuant to the Offer?

If you are the record owner of your Shares and you directly tender your Shares to us pursuant to the Offer, you will not have to pay brokerage fees or similar expenses. If you own your Shares through a broker, dealer, commercial bank, trust company or other nominee, and your broker, dealer, commercial bank, trust company or other nominee tenders your Shares on your behalf, your broker, dealer, commercial bank, trust company or other nominee may charge you a fee for doing so. You should consult your broker, dealer, commercial bank, trust company or other nominee to determine whether any charges will apply. See the “Introduction” to this Offer to Purchase.

We are making the Offer because the Purchaser and MTI want to acquire AMCOL. See Sections 1—“Terms of the Offer” and 13—“Purpose of the Offer; No Stockholder Approval; Plans for AMCOL.”

Yes. AMCOL, MTI and the Purchaser have entered into the Merger Agreement. The Merger Agreement provides, among other things, for the terms and conditions of the Offer and, following consummation of the Offer, the Merger. See Section 12—“The Transaction Agreements.”

Yes. After careful consideration, the AMCOL Board unanimously (i) adopted and declared the advisability of the Merger Agreement, the Offer, the Merger and the other transactions contemplated by the Merger Agreement, (ii) declared that it is in the best interests of AMCOL and the stockholders of AMCOL (other than MTI and its subsidiaries) that AMCOL enter into the Merger Agreement and consummate the Transactions and that the stockholders of AMCOL tender their Shares pursuant to the Offer, (iii) declared that the terms of the Offer and the Merger are fair to AMCOL and the stockholders of AMCOL (other than MTI and its subsidiaries) and (iv) resolved to recommend that the stockholders of AMCOL accept the Offer and tender their Shares pursuant to the Offer.

Accordingly, the AMCOL Board has unanimously recommended that you accept the Offer and tender your Shares pursuant to the Offer. AMCOL’s full statement on the Offer is set forth in its

Schedule 14D-9, which will be filed with the SEC in connection with the Offer and will be mailed to the stockholders of AMCOL with this Offer to Purchase and the Letter of Transmittal. See the “Introduction” to this Offer to Purchase.

The Offer is subject to certain other conditions as well. A more detailed discussion of the conditions to the Offer can be found in Section 15—“Conditions of the Offer.”

We reserve the right to waive some of the conditions to the Offer without AMCOL’s consent. We cannot, however, waive or change the Minimum Condition without the consent of AMCOL. See Section 15—“Conditions of the Offer.”

Is your financial condition relevant to my decision to tender my Shares pursuant to the Offer and do you have financial resources to make payment?

MTI and the Purchaser estimate that the total funds required to purchase all issued and outstanding Shares pursuant to the Offer and to complete the Merger pursuant to the Merger Agreement will be approximately $1,954,000,000, including related transaction fees and expenses and refinancing of indebtedness. MTI and the Purchaser anticipate funding these payments with cash on hand and from committed debt financing. We do not

believe that our financial condition is relevant to your decision whether to tender your Shares and accept the Offer because:

Receipt of financing is not a condition to the Offer. See Sections 10—“Source and Amount of Funds” and 12—“The Transaction Agreements—The Merger Agreement.”

How long do I have to decide whether to tender my Shares pursuant to the Offer?

Unless we extend or terminate the Offer, you will have until 9:00 a.m., New York City time, on April 18, 2014, to tender your Shares pursuant to the Offer. If we extend the Offer, you will have until the expiration of the Offer as so extended to tender your Shares pursuant to the Offer. Furthermore, if you cannot deliver everything required to make a valid tender by that time, you may still be able to participate in the Offer by using the guaranteed delivery procedure that is described later in this Offer to Purchase prior to that time. See Sections 1—“Terms of the Offer” and 3—“Procedures for Accepting the Offer and Tendering Shares.”

Yes. We have agreed in the Merger Agreement that so long as neither AMCOL nor MTI terminates the Merger Agreement in accordance with its terms:

We will, if on any then-scheduled Expiration Date the Minimum Condition has not been satisfied or any of the other Offer Conditions (as described in Section 15—“Conditions of the Offer”) has not been satisfied, or waived by MTI or us if permitted under the Merger Agreement, extend the Offer for one or more consecutive increments of not more than five business days each (or of not more than ten business days each if the only Offer Condition(s) not yet satisfied is the Offer Condition relating either to the absence of Restraints (as such term is defined in the Merger Agreement) or to the receipt of required regulatory approvals, as described in Section 15—“Conditions of the Offer”) (the length of such periods to be determined by MTI) or such other number of business days as we, MTI and AMCOL may agree upon (subject to our right of to waive any Offer Condition (other than the Minimum Condition) in accordance with the Merger Agreement), and the parties’ respective rights to terminate the Merger Agreement, until the earlier of (A) the termination of the Merger Agreement in accordance with its terms and (B) September 11, 2014. In addition, we will extend the Offer for the minimum period required (i) by applicable laws, statutes, ordinances, codes, rules, regulations, decrees judgments, injunctions and orders of any Governmental Authority, or (ii) the applicable rules, regulations, interpretations or positions of the SEC or its staff or the New York Stock Exchange (the “NYSE”). In addition, if on the then-scheduled Expiration Date, each of the Offer Conditions (as described in Section 15—“Conditions of the Offer”) has been satisfied, or waived by MTI or us if permitted under the Merger Agreement, and the Marketing Period (as such term is defined in the Merger Agreement and described below) did not end on or prior to the immediately preceding business day, then we shall have the right in our sole discretion to extend the Offer for one period of not more than ten business days (the length of such period to be determined by MTI), unless we or MTI are not then in compliance in all material respects with certain financing-related obligations under the Merger Agreement. See Section 12—“The Transaction Agreements—The Merger Agreement—Financing.”

See Section 1—“Terms of the Offer” for more details on our obligations and ability to extend the Offer.

If we extend the Offer, we will inform the Depositary of any extension and will issue a press release announcing the extension not later than 9:00 a.m., New York City time, on the next business day after the day on which the Offer was scheduled to expire. See Section 1—“Terms of the Offer.”

To tender Shares, you must deliver the certificates representing your Shares, together with a completed Letter of Transmittal and any other documents required by the Letter of Transmittal or any other customary documents required by the Depositary, to the Depositary prior to the Expiration Date. The Letter of Transmittal is enclosed with this Offer to Purchase. If your Shares are held in street name (i.e., through a broker, dealer, commercial bank, trust company or other nominee), your Shares can be tendered by your nominee by book-entry transfer through The Depository Trust Company. If you are unable to deliver any required document or instrument to the Depositary by the Expiration Date, you may gain some extra time by having a broker, a bank or other fiduciary that is an eligible guarantor institution guarantee that the missing items will be received by the Depositary by using the enclosed Notice of Guaranteed Delivery. For the tender to be valid, however, the Depositary must receive the missing items together with the Shares within three NYSE trading days after the date of execution of the Notice of Guaranteed Delivery. See Section 3—“Procedures for Accepting the Offer and Tendering Shares.”

In all cases, payment for tendered Shares will be made only after timely receipt by the Depositary of certificates for the Shares (or of a confirmation of a book-entry transfer of the Shares as described in Section 3—“Procedures for Accepting the Offer and Tendering Shares”) and a properly completed and duly executed Letter of Transmittal and any other required documents for the Shares. See Section 2—“Acceptance for Payment and Payment for Shares.”

You may withdraw your previously tendered Shares at any time prior to the expiration of the Offer and, unless previously accepted for payment as provided herein, tenders of Shares may also be withdrawn after the date that is 60 days from the date of this Offer to Purchase. See Section 4—“Withdrawal Rights.”

To withdraw previously tendered Shares, you must deliver a written notice of withdrawal, or a facsimile of one, with the required information to the Depositary while you still have the right to withdraw. If you tendered Shares by giving instructions to a broker, dealer, commercial bank, trust company or other nominee, you must instruct the broker, dealer, commercial bank, trust company or other nominee to arrange for the withdrawal of your Shares. See Section 4—“Withdrawal Rights.”

Will the consummation of the Offer be followed by a merger if less than all of the Shares are tendered pursuant to the Offer?

Yes. If we accept for payment at least such number of Shares as satisfies the Minimum Condition, as defined in Section 15—“Conditions of the Offer,” and the other conditions to the Merger are satisfied or waived, we, MTI and AMCOL will cause the merger of us into AMCOL to become effective as soon as practicable following the consummation of the Offer in accordance with the terms of the Merger Agreement and without a vote by the stockholders of AMCOL to adopt the Merger Agreement pursuant to Delaware law or any other action by the stockholders of AMCOL pursuant to Delaware law. If the Merger takes place, each Share issued

and outstanding immediately prior to the effective time of the Merger (other than (i) Shares held by AMCOL as treasury stock or owned by MTI or the Purchaser, all of which will be canceled and will cease to exist, and (ii) Shares owned by any stockholder of AMCOL who or which is entitled to demand, and who properly demands, appraisal rights pursuant to Section 262 of the DGCL) will be converted into the right to receive $45.75 per Share, net in cash, without interest and less any applicable withholding taxes (or any higher price per Share that is paid to the stockholders of AMCOL pursuant to the Offer) and AMCOL will become a wholly owned subsidiary of MTI. See the “Introduction” to this Offer to Purchase.

If a majority of Shares are tendered and are accepted for payment, will AMCOL continue as a public company?

No. Following the purchase of Shares tendered, we expect to promptly consummate the Merger in accordance with Section 251(h) of the DGCL, and no stockholder vote to adopt the Merger Agreement or any other action by the stockholders of AMCOL will be required in connection with the Merger. If the Merger occurs, AMCOL will no longer be publicly owned. We do not expect there to be a significant period of time between the consummation of the Offer and the consummation of the Merger. If you decide not to tender your Shares in the Offer and the Merger occurs as described above, you will receive as a result of the Merger the right to receive the same amount of cash per Share as if you had tendered your Shares in the Offer. Following the Offer, it is possible that the Shares might no longer constitute “margin securities” for purposes of the margin regulations of the Board of Governors’ of the Federal Reserve System, in which case your Shares may no longer be used as collateral for loans made by brokers. See Section 7—“NYSE Listing; Exchange Act Registration; Margin Regulations.”

If you successfully complete your Offer, what will happen to the AMCOL Board?

If we accept for payment at least such number of Shares as satisfies the Minimum Condition, as defined in Section 15—“Conditions of the Offer,” and subject to compliance with applicable Laws and the applicable rules of the NYSE, the Purchaser will be entitled to elect or designate such number of directors, rounded up to the next whole number, to the AMCOL Board as is equal the product of (i) the total number of directors on the AMCOL Board (after giving effect to the directors elected or designated by the Purchaser pursuant to this sentence) multiplied by (ii) the percentage that the aggregate number of Shares beneficially owned by MTI, the Purchaser and any of their subsidiaries bears to the total number of Shares then outstanding. See Section 12—“The Transaction Agreements.”

If you decide not to tender your Shares pursuant to the Offer and the Merger occurs as described above, you will receive as a result of the Merger the right to receive the same amount of cash per Share as if you had tendered your Shares pursuant to the Offer.

Subject to certain conditions, if we purchase Shares in the Offer, we are obligated under the Merger Agreement to cause the proposed Merger to occur.

Because the Merger will be governed by Section 251(h) of the DGCL, assuming the requirements of Section 251(h) of the DGCL are met, no stockholder vote to adopt the Merger Agreement or any other action by the stockholders of AMCOL will be required in connection with the Merger. We do not expect there to be significant time between the consummation of the Offer and the consummation of the Merger. See Section 7—“NYSE Listing; Exchange Act Registration; Margin Regulations.”

No. Pursuant to Section 251(h) of the DGCL and due to the obligation of MTI, the Purchaser and AMCOL to take all necessary and appropriate action to cause the Merger to become effective as soon as practicable

following the consummation of the Offer, we expect the Merger to occur on the date of, and as promptly as practicable following, the consummation of the Offer without a subsequent offering period. See Section 1—“Terms of the Offer.”

On February 11, 2014, the last full trading day prior to the public announcement of the recently terminated merger agreement among AMCOL, Imerys SA and Imerys Minerals Delaware, Inc., the last reported closing price per Share on NYSE during normal trading hours was $36.72 per Share. Therefore, the Offer Price of $45.75 per Share represents a premium of approximately 24.6% over the closing price of the Shares before the announcement of the Imerys merger agreement. On March 7, 2014, the last full trading day prior to the public announcement of the Merger Agreement, the last reported closing price per Share on the NYSE during normal trading hours was $46.66 per Share. On March 20, 2014, the last full trading day before we commenced the Offer, the last reported closing price per Share reported on NYSE was $45.73 per Share. See Section 6—“Price Range of Shares; Dividends.”

If the conditions to the Offer as described in Section 15—“Conditions of the Offer” are satisfied or waived and we consummate the Offer and accept your Shares for payment, we will pay you an amount equal to the number of Shares you tendered multiplied by $45.75 in cash, without interest and less any applicable withholding taxes promptly following the Expiration Date. See Sections 1—“Terms of the Offer” and 2—“Acceptance for Payment and Payment for Shares.”

How will my outstanding Options, Shares of Restricted Stock and RSUs be treated in the Offer and the Merger?

The Offer is being made for all outstanding Shares, but not for any outstanding equity or equity-based awards granted under the 2010 Long-Term Incentive Plan, the 2006 Long-Term Incentive Plan and the 1998 Long-Term Incentive Plan or any other plan, program or arrangement providing for the grant of equity-based awards (collectively, the “AMCOL Stock Plans”). No outstanding equity or equity-based awards granted under the AMCOL Stock Plans may be tendered in the Offer. In order to tender the Shares underlying an option or stock appreciation right granted under the AMCOL Stock Plans (each, an “Option”) for the Offer Price, Options must be exercised (to the extent they are exercisable) in accordance with their terms and in sufficient time to tender the Shares received pursuant to the Offer.

As of the Effective Time, the Options, Shares of Restricted Stock, RSUs, Phantom Shares and the AMCOL Stock Plans will be cancelled and of no further force or effect.

What are the United States federal income tax consequences of having my Shares accepted for payment in the Offer or receiving cash in the Merger?

The exchange of Shares for cash pursuant to the Offer or the Merger will be a taxable transaction for United States federal income tax purposes. In general, a stockholder that is a “U.S. holder” (as defined in Section 5—“Certain United States Federal Income Tax Consequences”) who sells Shares pursuant to the Offer or receives cash in exchange for Shares pursuant to the Merger will recognize gain or loss for United States federal income tax purposes in an amount equal to the difference, if any, between the amount of cash received and the stockholder’s adjusted tax basis in the Shares sold pursuant to the Offer or exchanged for cash pursuant to the Merger. Gain or loss will be determined separately for each block of Shares (that is, Shares acquired at the same cost in a single transaction) tendered pursuant to the Offer or exchanged for cash pursuant to the Merger. Such gain or loss will generally be long-term capital gain or loss provided that the stockholder’s holding period for such Shares is more than one year at the time of consummation of the Offer or the Merger, as the case may be. See Section 5—“Certain United States Federal Income Tax Consequences.”

Stockholders are urged to consult their tax advisors to determine the particular tax consequences to them (including the application and effect of any United States federal estate or gift tax rules, or any state, local or non-United States income and other tax laws) of the Offer and the Merger.

No appraisal rights are available in connection with the Offer, and AMCOL stockholders who tender shares in the Offer will not have appraisal rights in connection with the Merger. If the Merger is consummated, however, AMCOL stockholders whose Shares have not been purchased by Purchaser pursuant to the Offer will have certain rights under Section 262 of the DGCL, to demand appraisal of, and to receive payment in cash of the fair value of, their Shares. AMCOL stockholders that perfect these rights by complying with the procedures set forth in Section 262 of the DGCL will have the fair value of their Shares (exclusive of any element of value arising from the accomplishment or expectation of the Merger) determined by the Delaware Court of Chancery and will be entitled to receive a cash payment equal to such fair value from AMCOL. Any such judicial determination of the fair value of Shares could be based upon considerations other than, or in addition to, the price paid in the Offer and the market value of the Shares, including asset values and the investment value of the Shares. The value so determined could be more or less than the price paid by Purchaser pursuant to the Offer and the Merger. You should be aware that an investment banking opinion as to the fairness, from a financial point of view, of the consideration payable in a sale transaction, such as the Offer or the Merger, is not an opinion as to fair value under Section 262 of the DGCL. If any stockholder of AMCOL who demands appraisal under Section 262 of the DGCL fails to perfect, or effectively withdraws or loses his or her right to appraisal, as provided in the DGCL, each of the Shares of such holder will be converted into the right to receive an amount equal to the Offer Price.

The foregoing summary of the rights of AMCOL stockholders under the DGCL is qualified in its entirety by the full text of Section 262 of the DGCL, which is filed as Annex C to AMCOL’s Solicitation/Recommendation Statement on Schedule 14D-9 that is being mailed to you with this Offer to Purchase, and which is incorporated herein by reference. A more detailed discussion of appraisal rights can be found in Section 16—“Certain Legal Matters; Regulatory Approvals.”

You may call Innisfree M&A Incorporated at (888) 750-5834 (toll free). Innisfree M&A Incorporated is acting as the Information Agent for the Offer and Lazard Frères & Co. LLC is acting as the Dealer Manager for the Offer. See the back cover of this Offer to Purchase.

MA Acquisition Inc., a Delaware corporation (the “Purchaser”) and a wholly owned subsidiary of Minerals Technologies Inc., a Delaware corporation (“MTI”), hereby offers to purchase (the “Offer”) all outstanding shares of common stock, par value $0.01 per share (each, a “Share”), of AMCOL International Corporation, a Delaware corporation (“AMCOL”), at a price of $45.75 per Share net to the seller in cash, without interest (the “Offer Price”) and less any applicable withholding taxes, upon the terms and subject to the conditions set forth in this Offer to Purchase (as it may be amended or supplemented, this “Offer to Purchase”) and in the related Letter of Transmittal (as it may be amended or supplemented, the “Letter of Transmittal”).

The Offer is being made pursuant to the Agreement and Plan of Merger, dated as of March 10, 2014 (as it may be amended or supplemented, the “Merger Agreement”), by and among AMCOL, MTI and the Purchaser. The Offer is conditioned upon (i) the satisfaction of the Minimum Condition, as defined in Section 15—“Conditions of the Offer,” (ii) the expiration or termination of any waiting period (and any extension thereof) applicable to the consummation of the Offer under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (the “HSR Act”) and the grant of any required approval of the Offer, the Merger (as defined below) and the other transactions contemplated by the Merger Agreement (collectively, the “Transactions”) by any federal, state or local, domestic, foreign or multinational government, court, regulatory or administrative agency, commission, authority or other governmental instrumentality (“Governmental Authority”) (or all applicable waiting periods (and any extensions thereof) shall have been terminated or shall have expired) pursuant to any foreign antitrust laws in Germany, Poland and Turkey, (iii) the absence of a Company Material Adverse Effect and (iv) certain other conditions described in Section 15—“Conditions of the Offer.” The term “Minimum Condition” is defined in Section 15—“Conditions of the Offer” and generally requires that the Shares which have been validly tendered and not validly withdrawn (not including as tendered those Shares that are tendered pursuant to guaranteed delivery procedures and not actually delivered prior to the Expiration Date) prior to the Expiration Date, when added to any Shares already owned by MTI or the Purchaser or any of their respective subsidiaries, represent one Share more than one-half (1/2) of the sum of: (i) all Shares then outstanding, and (ii) all Shares that AMCOL may be required to issue upon the vesting, conversion, settlement or exercise of all then outstanding warrants, options, obligations or securities convertible or exchangeable into Shares, or other rights to acquire or be issued Shares. The term “Company Material Adverse Effect” is defined in Section 12—“The Transaction Agreements.” The Offer is also subject to other conditions set forth in this Offer to Purchase. See Section 15—“Conditions of the Offer.”

AMCOL has advised MTI that, as of the close of business on March 13, 2014, there were (i) 32,593,030 Shares issued and outstanding, (ii) 22,857 Shares held by AMCOL in its treasury, (iii) an aggregate of 2,138,498 Shares reserved for issuance under the AMCOL Stock Plans (as defined below), of which (A) Options (as defined below) were issued with respect to 1,202,180 Shares (of which, options were issued with respect to 936,333 Shares and stock appreciation rights were issued with respect to 265,847 Shares), (B) no Shares were subject to restricted stock awards, (C) 129,300 Shares were subject to restricted stock unit awards and (D) 95,430 phantom shares were credited under a deferred compensation plan.

The Merger Agreement is more fully described in Section 12—“The Transaction Agreements.”

Tendering stockholders who are record owners of their Shares and tender directly to American Stock Transfer & Trust Company, LLC, the depositary for the Offer (the “Depositary”), will not be obligated to pay brokerage fees or commissions or, except as otherwise provided in Instruction 6 of the Letter of Transmittal, stock transfer taxes with respect to the purchase of Shares by the Purchaser pursuant to the Offer. Stockholders who hold their Shares through a broker, dealer, commercial bank, trust company or other nominee should consult such institution as to whether it charges any service fees or commissions.

After careful consideration, the board of directors of AMCOL (the “AMCOL Board”) unanimously (i) adopted and declared the advisability of the Merger Agreement, the Offer, the Merger and the other transactions contemplated by the Merger Agreement, (ii) declared that it is in the best interests of AMCOL and the stockholders of AMCOL (other than MTI and its subsidiaries) that AMCOL enter into the Merger Agreement and consummate the Merger and the other transactions contemplated by the Merger Agreement and that the stockholders of AMCOL accept the Offer and tender their Shares pursuant to the Offer, (iii) declared that the terms of the Offer and the Merger are fair to AMCOL and the stockholders of AMCOL (other than MTI and its subsidiaries) and (iv) resolved to recommend that the stockholders of AMCOL accept the Offer and tender their Shares to the Purchaser pursuant to the Offer.

A complete description of the reasons for the AMCOL Board’s approval of the Offer and the Merger will be set forth in AMCOL’s Solicitation/Recommendation Statement on Schedule 14D-9 (the “Schedule 14D-9”) that is being mailed to you with this Offer to Purchase.

The Merger Agreement provides that, subject to the conditions described in Section 12—“The Transaction Agreements,” the Purchaser will be merged with and into AMCOL with AMCOL continuing as the surviving corporation (the “Surviving Corporation”), wholly owned by MTI (the “Merger”). Pursuant to the Merger Agreement, at the effective time of the Merger (the “Effective Time”), each Share outstanding immediately prior to the Effective Time will be converted into the right to receive $45.75 per Share (or any greater per Share price paid in the Offer), net in cash, without interest and less any applicable withholding tax, other than (i) Shares held by AMCOL as treasury stock or owned by MTI or the Purchaser, all of which will be canceled and will cease to exist and (ii) Shares owned by any stockholder of AMCOL who or which is entitled to demand, and who properly demands, appraisal rights pursuant to Section 262 of the General Corporation Law of the State of Delaware (the “DGCL”).

Section 251(h) of the DGCL provides that, subject to certain statutory requirements, if following consummation of a successful tender offer for a public corporation, the acquiror holds at least the amount of shares of each class of stock of the target corporation that would otherwise be required to approve a merger involving the target corporation, and the other stockholders receive the same consideration for their stock in the merger as was payable in the tender offer, the acquiror can effect a merger without any action of the other stockholders of the target corporation. Therefore, AMCOL, MTI and the Purchaser have agreed that, subject to the conditions specified in the Merger Agreement, the Merger will become effective as soon as practicable after the consummation of the Offer, without a meeting of the stockholders of AMCOL to adopt the Merger Agreement, in accordance with Section 251(h) of the DGCL. See Section 13—“Purpose of the Offer; No Stockholder Approval; Plans for AMCOL.”

The Offer is conditioned upon the fulfillment of the conditions described in Section 15—“Conditions of the Offer.”

The Offer and withdrawal rights will expire at 9:00 a. m., New York City time, on April 18, 2014, unless the Offer is extended (such date and time, as it may be so extended, the “Expiration Date”) unless earlier terminated by the Purchaser). See Section 12—“The Transaction Agreements—The Merger Agreement.”

THE OFFER TO PURCHASE, THE LETTER OF TRANSMITTAL AND AMCOL’S SOLICITATION/RECOMMENDATION STATEMENT ON SCHEDULE 14D-9 (WHICH CONTAINS THE RECOMMENDATION OF THE AMCOL BOARD AND THE REASONS FOR THEIR RECOMMENDATION) CONTAIN IMPORTANT INFORMATION. STOCKHOLDERS OF AMCOL SHOULD CAREFULLY READ THESE DOCUMENTS IN THEIR ENTIRETY BEFORE MAKING A DECISION WITH RESPECT TO THE OFFER.

Upon the terms and subject to the conditions of the Offer (including, if the Offer is extended or amended, the terms and conditions of such extension or amendment), the Purchaser will accept for payment and pay for all Shares validly tendered prior to the Expiration Date and not validly withdrawn as permitted under Section 4—“Withdrawal Rights.”

The Offer is conditioned upon (i) the satisfaction of the Minimum Condition, (ii) the satisfaction of the Regulatory Condition, (iii) the absence of a Company Material Adverse Effect on AMCOL and (iv) the other conditions described in Section 15—“Conditions of the Offer.” The term “Minimum Condition” is defined in Section 15—“Conditions of the Offer” and generally requires that the Shares which have been validly tendered and not validly withdrawn (not including as tendered those Shares that are tendered pursuant to guaranteed delivery procedures and not actually delivered prior to the Expiration Date) prior to the Expiration Date, when added to any Shares already owned by MTI or the Purchaser or any of their respective subsidiaries, represent one Share more than one-half (1/2) of the sum of: (i) all Shares then outstanding, and (ii) all Shares that AMCOL may be required to issue upon the vesting, conversion, settlement or exercise of all then outstanding warrants, options, obligations or securities convertible or exchangeable into Shares, or other rights to acquire or be issued Shares. The term “Company Material Adverse Effect” is defined in Section 12—“The Transaction Agreements.” The Offer is also subject to other conditions set forth in this Offer to Purchase. See Section 15—“Conditions of the Offer.” We may terminate the Offer without purchasing any Shares if certain events described in Section 12—“The Transaction Agreements” occur.

Subject to the applicable rules and regulations of the SEC and the provisions of the Merger Agreement, the Purchaser expressly reserves the right, in its sole discretion, to waive any condition of the Offer in whole or in part, or to modify the terms or conditions of the Offer, except that, without the written consent of AMCOL, the Purchaser may not (A) decrease the Offer Price, except in the case of certain agreed upon equitable adjustments, (B) change the form of consideration payable in the Offer, (C) decrease the maximum number of Shares sought to be purchased in the Offer, (D) amend or modify any of the Offer condition in a manner that adversely affects holders of shares generally, (E) change the Minimum Condition, (F) impose conditions to the Offer in addition to the Offer conditions (G) extend or otherwise change the Expiration Date in a manner other than as required or permitted by the Merger Agreement, or (H) provide for a “subsequent offering period” (or any extension thereof) in accordance with Rule 14d-11 under the Exchange Act. The rights reserved by the Purchaser by this paragraph are in addition to the Purchaser’s rights pursuant to Section 15—“Conditions of the Offer.”

We may, in our sole and absolute discretion, increase the amount of cash constituting the Offer Price without the consent of AMCOL. If, on or before the Expiration Date, we increase the consideration being paid for Shares accepted for payment in the Offer, this increased consideration will be paid to all stockholders whose Shares are purchased in the Offer, whether or not their Shares were tendered before the announcement of the increase in consideration.

The Merger Agreement provides that if at the Expiration Date the Minimum Condition has not been satisfied or any of the other Offer Conditions (as described in Section 15—“Conditions of the Offer”) has not been satisfied, or waived by MTI or us if permitted thereunder, we will extend the Offer for one or more consecutive increments of not more than five business days each (or of not more than ten business days each if the only Offer Condition(s) not yet satisfied is the Offer Condition relating either to the absence of Restraints or to the receipt of required regulatory approvals, as described in Section 15—“Conditions of the Offer”) (the length of such periods to be determined by MTI) or such other number of business days as we, MTI and AMCOL may agree upon (subject to our right to waive any Offer Condition (other than the Minimum Condition) in accordance with the Merger Agreement, and the parties’ respective rights to terminate the Merger Agreement) until the earlier of (A) the termination of the Merger Agreement in accordance with its terms and

(B) September 11, 2014. In addition, the Purchaser will extend the Offer for any period required by any rule, regulation, interpretation or position of the SEC, the staff thereof or the New York Stock Exchange (the “NYSE”) applicable to the Offer or as may be required by any other United States federal, state or local or any Governmental Authority). In addition, if on the then-scheduled Expiration Date, each of the Offer Conditions (as described in Section 15—“Conditions of the Offer”) has been satisfied, or waived by MTI or us if permitted under the Merger Agreement, and the Marketing Period (as such term is defined in the Merger Agreement and described below) did not end on or prior to the immediately preceding business day, then we shall have the right in our sole discretion to extend the Offer for one period of not more than ten business days (the length of such period to be determined by MTI), unless we or MTI are not then in compliance in all material respects with certain financing-related obligations under the Merger Agreement. See Section 12—“The Transaction Agreements—The Merger Agreement—Financing.”

There can be no assurance that the Purchaser will be required under the Merger Agreement to extend, or choose to extend (if not so required) the Offer. During any extension of the offering period pursuant to the paragraphs above, all Shares previously tendered and not validly withdrawn will remain subject to the Offer and subject to withdrawal rights. See Section 4—“Withdrawal Rights.”

If, upon the terms and subject to the conditions to the Merger Agreement, the Purchaser makes a material change in the terms of the Offer or the information concerning the Offer, or if the Purchaser waives a material condition of the Offer, the Purchaser will disseminate additional tender offer materials and will extend the Offer, in each case, if and to the extent required by Rules 14d-4(d), 14d-6(c) and l4e-1 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”) or otherwise. The minimum period during which a tender offer must remain open following material changes in the terms of such tender offer or the information concerning such tender offer, other than a change in the consideration offered or a change in the percentage of securities sought, will depend upon the facts and circumstances, including the relative materiality of the terms or information changes. With respect to a change in the consideration offered or a change in the percentage of securities sought, a tender offer generally must remain open for a minimum of ten business days following such change to allow for adequate disclosure to stockholders.

The Purchaser expressly reserves the right, in its sole discretion, upon the terms and subject to the conditions to the Merger Agreement and the applicable rules and regulations of the SEC, to not accept for payment or pay for any Shares and to delay the acceptance for payment of or payment for Shares if, at the Expiration Date, any of the conditions to the Offer set forth in Section 15—“Conditions of the Offer” have not been satisfied or waived or upon the occurrence of any of the events set forth in Section 15—“Conditions of the Offer.” The Purchaser’s reservation of the right to delay the acceptance of, or payment for, Shares is subject to the provisions of Rule 14e-1(c) under the Exchange Act, which requires that the Purchaser pay the consideration offered or return Shares deposited by or on behalf of tendering stockholders promptly after the termination of the Offer. Under certain circumstances, MTI and the Purchaser may terminate the Merger Agreement and the Offer. See Section 12—“The Transaction Agreements—The Merger Agreement—Termination.”

Any extension, waiver or amendment of the Offer, or delay in acceptance for payment or payment, or termination of the Offer will be followed, as promptly as practicable, by public announcement thereof, such announcement in the case of an extension to be issued not later than 9:00 a.m., New York City time, on the next business day after the previously scheduled Expiration Date in accordance with the public announcement requirements of Rules 14d-4(d), 14d-6(c) and l4e-1(d) under the Exchange Act. Without limiting the Purchaser’s obligation under such rules or the manner in which the Purchaser may choose to make any public announcement, the Purchaser currently intends to make announcements by issuing a press release and making any appropriate filing with the SEC.

Following the purchase of Shares tendered, we expect to consummate the Merger in accordance with Section 251(h) of the DGCL, and no stockholder vote to adopt the Merger Agreement or any other action by the stockholders of AMCOL will be required in connection with the Merger. We do not expect there to be a significant period of time between the consummation of the Offer and the consummation of the Merger.

AMCOL has provided the Purchaser with its list of stockholders and security position listings for the purpose of disseminating the Offer to holders of Shares. This Offer to Purchase and the related Letter of Transmittal will be mailed to record holders of Shares whose names appear on AMCOL’s stockholder list and will be furnished to brokers, dealers, commercial banks, trust companies and similar persons whose names, or the names of whose nominees, appear on the stockholder list or, if applicable, who are listed as participants in a clearing agency’s security position listing, for subsequent transmittal to beneficial owners of Shares.

Upon the terms and subject to the conditions to the Offer (including, if the Offer is extended or amended, the terms and conditions of any such extension or amendment), the Purchaser will (i) promptly following the Expiration Date, accept for payment all Shares validly tendered and not validly withdrawn, prior to the Expiration Date and (ii) promptly thereafter pay for all such Shares as soon as practicable following the Expiration Date. Acceptance for payment of Shares pursuant to and subject to the conditions of the Offer is referred to as the “Offer Closing” and the date on which the Offer Closing occurs is the “Offer Closing Date.”

In all cases, payment for Shares tendered and accepted for payment pursuant to the Offer will be made only after timely receipt by the Depositary of (i) certificates representing such Shares or confirmation of the book-entry transfer of such Shares into the Depositary’s account at The Depository Trust Company (“DTC” or the “Book-Entry Transfer Facility”) pursuant to the procedures set forth in Section 3—“Procedures for Accepting the Offer and Tendering Shares,” (ii) a Letter of Transmittal (or facsimile thereof), properly completed and duly executed, with any required signature guarantees (or, in the case of a book-entry transfer, an Agent’s Message (as defined in Section 3 below) in lieu of the Letter of Transmittal) and (iii) any other documents required by the Letter of Transmittal or any other customary documents required by the Depositary. See Section 3—“Procedures for Accepting the Offer and Tendering Shares.”

For purposes of the Offer, the Purchaser will be deemed to have accepted for payment and thereby purchased Shares validly tendered and not validly withdrawn, prior to the Expiration Date if and when the Purchaser gives oral or written notice to the Depositary of its acceptance for payment of such Shares pursuant to the Offer and the conditions of the Offer have been satisfied or waived, to the extent permissible under the Merger Agreement. Upon the terms and subject to the conditions of the Offer, payment for Shares accepted for payment pursuant to the Offer will be made by deposit of the purchase price therefor with the Depositary, which will act as agent for the tendering stockholders for purposes of receiving payments from the Purchaser and transmitting such payments to the tendering stockholders. Under no circumstances will interest be paid on the Offer Price for Shares, regardless of any extension of the Offer or any delay in payment for Shares.

If any tendered Shares are not accepted for payment pursuant to the terms and conditions of the Offer for any reason, or if certificates are submitted for more Shares than are tendered, certificates for these unpurchased Shares will be returned (or new certificates for the Shares not tendered will be sent), without expense to the tendering stockholder (or, in the case of Shares tendered by book-entry transfer into the Depositary’s account at the Book-Entry Transfer Facility pursuant to the procedures set forth in Section 3—“Procedures for Accepting the Offer and Tendering Shares,” these Shares will be credited to an account maintained with the Book-Entry Transfer Facility) promptly following expiration or termination of the Offer.

Valid Tender of Shares. Except as set forth below, to validly tender Shares pursuant to the Offer, (i) a properly completed and duly executed Letter of Transmittal (or a manually executed photocopies thereof) in accordance with the instructions of the Letter of Transmittal, with any required signature guarantees, or an Agent’s Message (as defined herein) in connection with a book-entry delivery of Shares, and any other documents required by the Letter of Transmittal or any other customary documents required by the Depositary, must be received by the Depositary at its address as set forth on the back cover of this Offer to Purchase prior to

the Expiration Date and either (A) certificates representing Shares tendered must be delivered to the Depositary or (B) these Shares must be properly delivered pursuant to the procedures for book-entry transfer described below and a confirmation of such delivery received by the Depositary (which confirmation must include an Agent’s Message if the tendering stockholder has not delivered a Letter of Transmittal), in each case, prior to the Expiration Date or (ii) the tendering stockholder must comply with the guaranteed delivery procedures set forth below. The term “Agent’s Message” means a message, transmitted by the Book-Entry Transfer Facility to, and received by, the Depositary and forming a part of a Book-Entry Confirmation (as defined herein), which states that the Book-Entry Transfer Facility has received an express acknowledgment from the participant in the Book-Entry Transfer Facility tendering the Shares that are the subject of such Book-Entry Confirmation that such participant has received and agrees to be bound by the terms of the Letter of Transmittal and that the Purchaser may enforce such agreement against the participant.

Book-Entry Transfer. The Depositary will establish an account with respect to the Shares at the Book-Entry Transfer Facility for purposes of the Offer within two business days after the date of this Offer to Purchase. Any financial institution that is a participant in the Book-Entry Transfer Facility’s systems may make a book-entry transfer of Shares by causing the Book-Entry Transfer Facility to transfer the Shares into the Depositary’s account in accordance with the Book-Entry Transfer Facility’s procedures for the transfer. However, although delivery of Shares may be effected through book-entry transfer, either the Letter of Transmittal (or facsimile thereof), properly completed and duly executed, together with any required signature guarantees, or an Agent’s Message in lieu of the Letter of Transmittal, and any other required documents, must, in any case, be transmitted to and received by the Depositary at its address as set forth on the back cover of this Offer to Purchase by the Expiration Date, or the tendering stockholder must comply with the guaranteed delivery procedures described below. The confirmation of a book-entry transfer of Shares into the Depositary’s account at the Book-Entry Transfer Facility as described above is referred to herein as a “Book-Entry Confirmation.”

Delivery of documents to DTC in accordance with DTC’s procedures does not constitute delivery to the Depositary.

Signature Guarantees and Stock Powers. Except as otherwise provided below, all signatures on a Letter of Transmittal must be guaranteed by a financial institution (including most commercial banks, savings and loan associations and brokerage houses) that is a member in good standing of a recognized Medallion Program approved by the Securities Transfer Association, Inc., including any of the Security Transfer Agents Medallion Program, the New York Stock Exchange Medallion Signature Program and the Stock Exchanges Medallion Program or an “eligible guarantor institution,” as such term is defined in Rule 17Ad-15 of the Exchange Act (each, an “Eligible Institution”). Signatures on a Letter of Transmittal need not be guaranteed (i) if the Letter of Transmittal is signed by the registered owner(s) (which term, for purposes of this Section 3—“Procedures for Accepting the Offer and Tendering Shares,” includes any participant in any of the Book-Entry Transfer Facility’s systems whose name appears on a security position listing as the owner of the Shares) of Shares tendered therewith and such registered owner has not completed the box entitled “Special Payment Instructions” or the box entitled “Special Delivery Instructions” on the Letter of Transmittal or (ii) if such Shares are tendered for the account of an Eligible Institution. See Instructions 1 and 5 of the Letter of Transmittal. If the certificates for Shares are registered in the name of a person other than the signer of the Letter of Transmittal, or if payment is to be made or certificates for Shares not tendered or not accepted for payment are to be returned to a person other than the registered owner of the certificates surrendered, then the tendered certificates must be endorsed or accompanied by appropriate stock powers, in either case, signed exactly as the name or names of the registered owner(s) or holder(s) appear on the certificates, with the signatures on the certificates or stock powers guaranteed as described above. See Instructions 1 and 5 of the Letter of Transmittal.

If certificates representing Shares are forwarded separately to the Depositary, a properly completed and duly executed Letter of Transmittal (or facsimile) must accompany each delivery of certificates.

Guaranteed Delivery. A stockholder who desires to tender Shares pursuant to the Offer and whose certificates for Shares are not immediately available and cannot be delivered to the Depositary prior to the

Expiration Date, or who cannot complete the procedure for book-entry transfer prior to the Expiration Date, or who cannot deliver all required documents to the Depositary prior to the Expiration Date, may tender such Shares by satisfying all of the requirements set forth below:

The Notice of Guaranteed Delivery may be delivered by hand to the Depositary or transmitted by telegram, facsimile transmission or mail to the Depositary and must include a guarantee by an Eligible Institution in the form set forth in such Notice of Guaranteed Delivery.

Shares tendered by a Notice of Guaranteed Delivery will not be deemed validly tendered for purposes of satisfying the Minimum Condition unless and until the Shares to which such Notice of Guaranteed Delivery relates are delivered to the Depositary.

THE METHOD OF DELIVERY OF SHARES, THE LETTER OF TRANSMITTAL AND ALL OTHER REQUIRED DOCUMENTS, INCLUDING DELIVERY THROUGH THE BOOK-ENTRY TRANSFER FACILITY, IS AT THE ELECTION AND RISK OF THE TENDERING STOCKHOLDER. DELIVERY OF ALL SUCH DOCUMENTS WILL BE DEEMED MADE ONLY WHEN ACTUALLY RECEIVED BY THE DEPOSITARY (INCLUDING, IN THE CASE OF A BOOK-ENTRY TRANSFER, BY BOOK-ENTRY CONFIRMATION). IF THIS DELIVERY IS BY MAIL, IT IS RECOMMENDED THAT ALL SUCH DOCUMENTS BE SENT BY PROPERLY INSURED REGISTERED MAIL WITH RETURN RECEIPT REQUESTED. IN ALL CASES, SUFFICIENT TIME SHOULD BE ALLOWED TO ENSURE TIMELY DELIVERY.

Other Requirements. Notwithstanding any provision of the Merger Agreement, the Purchaser will pay for Shares validly tendered and not validly withdrawn pursuant to the Offer prior to the Expiration Date only after timely receipt by the Depositary of (i) certificates for (or a timely Book-Entry Confirmation with respect to) these Shares, (ii) a Letter of Transmittal (or facsimile thereof), properly completed and duly executed, with any required signature guarantees (or, in the case of a book-entry transfer, an Agent’s Message in lieu of the Letter of Transmittal) and (iii) any other documents required by the Letter of Transmittal or any other customary documents required by the Depositary. Accordingly, tendering stockholders may be paid at different times depending upon when certificates for Shares or Book-Entry Confirmations with respect to Shares are actually received by the Depositary. Under no circumstances will the Purchaser pay interest on the purchase price of Shares, regardless of any extension of the Offer or any delay in making such payment. If your Shares are held in street name (i.e., through a broker, dealer, commercial bank, trust company or other nominee), your Shares can be tendered by your nominee by book-entry transfer through the Depositary. If you are unable to deliver any required document or instrument to the Depositary by the Expiration Date, you may gain some extra time by having a broker, a bank or other fiduciary that is an eligible guarantor institution guarantee that the missing items will be received by the Depositary by using the enclosed Notice of Guaranteed Delivery. For the tender to be valid, however, the Depositary must receive the missing items together with the Shares within three NYSE trading days after the date of execution of the Notice of Guaranteed Delivery.

Binding Agreement. Our acceptance for payment of Shares tendered pursuant to one of the procedures described above will constitute a binding agreement between the tendering stockholder and the Purchaser upon the terms and subject to the conditions of the Offer.

Appointment as Proxy. By executing and delivering a Letter of Transmittal as set forth above (or, in the case of a book-entry transfer, by delivery of an Agent’s Message in lieu of a Letter of Transmittal), the tendering stockholder irrevocably appoints the Purchaser’s designees as such stockholder’s proxies, each with full power of substitution, to the full extent of such stockholder’s rights with respect to the Shares tendered by such stockholder and accepted for payment by the Purchaser and with respect to any and all other Shares or other securities issued or issuable in respect of such Shares on or after the date of the Merger Agreement. All such proxies and powers of attorney will be considered coupled with an interest in the tendered Shares. Such appointment is effective when, and only to the extent that, the Purchaser accepts for payment Shares tendered by such stockholder as provided herein. Upon the effectiveness of such appointment, all prior powers of attorney, proxies and consents given by such stockholder will be revoked, and no subsequent powers of attorney, proxies and consents may be given (and, if given, will not be deemed effective). Our designees will, with respect to the Shares or other securities and rights for which the appointment is effective, be empowered to exercise all voting and other rights of such stockholder as they, in their sole discretion, may deem proper at any annual, special, adjourned or postponed meeting of the stockholders of AMCOL, by written consent in lieu of any such meeting or otherwise. The Purchaser reserves the right to require that, in order for Shares to be deemed validly tendered, immediately upon payment for such Shares, the Purchaser must be able to exercise full voting, consent and other rights to the extent permitted under applicable law with respect to such Shares and other securities, including voting at any meeting of stockholders or executing a written consent concerning any matter.

Determination of Validity. All questions as to the validity, form, eligibility (including time of receipt) and acceptance of any tender of Shares will be determined by the Purchaser in its sole and absolute discretion, which determination will be final and binding. The Purchaser reserves the absolute right to reject any and all tenders determined by the Purchaser not to be in proper form or the acceptance for payment of or payment for which may, in the Purchaser’s opinion, be unlawful. The Purchaser also reserves the absolute right to waive any defect or irregularity in the tender of any Shares of any particular stockholder whether or not similar defects or irregularities are waived in the case of any other stockholder. No tender of Shares will be deemed to have been validly made until all defects and irregularities relating thereto have been cured or waived. None of MTI, the Purchaser or any of their respective affiliates or assigns, the Depositary, Innisfree M&A Incorporated (the “Information Agent”), Lazard Frères & Co. LLC (the “Dealer Manager”) or any other person will be under any duty to give notification of any defects or irregularities in tenders or incur any liability for failure to give any such notification. Subject to the Purchaser’s obligations under the Merger Agreement, the Purchaser’s interpretation of the terms and conditions of the Offer (including the Letter of Transmittal and the Instructions thereto and any other documents related to the Offer) will be final and binding.

Backup Withholding. In order to avoid United States federal backup withholding at a rate of 28% on payments of cash pursuant to the Offer, a stockholder that is a “U.S. person” (as defined in the instructions to the Internal Revenue Service (“IRS”) Form W-9 provided with the Letter of Transmittal) who surrenders Shares in the Offer must, unless an exemption applies, provide the Depositary with such stockholder’s correct taxpayer identification number (“TIN”) on an IRS Form W-9, certify under penalties of perjury that such TIN is correct and provide certain other certifications. If a stockholder does not provide such stockholder’s correct TIN or fails to provide the required certifications, the IRS may impose a penalty on such stockholder, and payment of cash to such stockholder pursuant to the Offer may be subject to backup withholding at a rate of 28%. All stockholders that are U.S. persons surrendering Shares pursuant to the Offer should complete and sign the IRS Form W-9 included as part of the Letter of Transmittal to provide the information and certifications necessary to avoid backup withholding (unless an applicable exemption exists and is proved in a manner satisfactory to the Purchaser and the Depositary). Certain stockholders (including, among others, all corporations and certain foreign individuals and entities) are not subject to backup withholding. Foreign stockholders should complete and sign an appropriate IRS Form W-8 (instead of an

IRS Form W-9) in order to avoid backup withholding. The various IRS Forms W-8 may be obtained from the Depositary or at www.irs.gov. See Instruction 9 to the Letter of Transmittal.

Except as otherwise provided in this Section 4—“Withdrawal Rights,” tenders of Shares pursuant to the Offer are irrevocable. However, a stockholder may withdraw Shares tendered pursuant to the Offer at any time prior to the Expiration Date as explained below. Further, if the Purchaser has not accepted Shares for payment by May 19, 2014, they may be withdrawn at any time prior to the Purchaser’s acceptance for payment after that date.

For a withdrawal of Shares to be effective, a written or facsimile transmission notice of withdrawal must be timely received by the Depositary at its address set forth on the back cover of this Offer to Purchase. Any notice of withdrawal must specify the name of the person having tendered the Shares to be withdrawn, the number of Shares to be withdrawn and the name of the registered holder of the Shares to be withdrawn, if different from that of the person who tendered such Shares. The signature(s) on the notice of withdrawal must be guaranteed by an Eligible Institution, unless such Shares have been tendered for the account of any Eligible Institution. If Shares have been tendered pursuant to the procedures for book-entry transfer as set forth in Section 3—“Procedures for Accepting the Offer and Tendering Shares,” any notice of withdrawal must specify the name and number of the account at the Book-Entry Transfer Facility to be credited with the withdrawn Shares. If certificates representing the Shares have been delivered or otherwise identified to the Depositary, the name of the registered owner and the serial numbers shown on such certificates must also be furnished to the Depositary prior to the physical release of such certificates.

All questions as to the form and validity (including time of receipt) of any notice of withdrawal will be determined by the Purchaser, in its sole discretion, which determination will be final and binding. No withdrawal of Shares will be deemed to have been validly made until all defects and irregularities have been cured or waived. None of MTI, the Purchaser or any of their respective affiliates or assigns, the Depositary, the Information Agent, the Dealer Manager or any other person will be under any duty to give notification of any defects or irregularities in any notice of withdrawal or incur any liability for failure to give such notification. Withdrawals of tenders of Shares may not be rescinded, and any Shares validly withdrawn will be deemed not to have been validly tendered for purposes of the Offer. However, validly withdrawn Shares may be retendered by following one of the procedures for tendering Shares described in Section 3—“Procedures for Accepting the Offer and Tendering Shares” at any time prior to the Expiration Date.

If the Purchaser extends the Offer, delays its acceptance for payment of Shares or is unable to accept for payment Shares pursuant to the Offer, for any reason, then, without prejudice to the Purchaser’s rights under the Offer, the Depositary may nevertheless, on the Purchaser’s behalf, retain tendered Shares, and such Shares may not be withdrawn except to the extent that tendering stockholders exercise withdrawal rights as described in this Section 4—“Withdrawal Rights” prior to the Expiration Date or as otherwise required by Rule 14e-1(c) under the Exchange Act.

The following is a summary of certain United States federal income tax consequences of the Offer and the Merger to stockholders of AMCOL whose Shares are tendered and accepted for payment pursuant to the Offer or whose Shares are not tendered but instead are converted into the right to receive cash in the Merger. The discussion is for general information only and does not purport to consider all aspects of United States federal income taxation that might be relevant to stockholders of AMCOL, nor does it address any aspects of the United States federal estate or gift tax rules or any state, local or non-United States income or other tax laws that may apply to a particular stockholder in connection with the Offer and the Merger. The discussion is based on current provisions of the Internal Revenue Code of 1986, as amended (the “Code”), existing, proposed and temporary

regulations thereunder and administrative and judicial interpretations thereof, all of which are subject to change, possibly with a retroactive effect. The discussion applies only to stockholders of AMCOL who hold Shares as capital assets for United States federal income tax purposes. This discussion does not address all of the United States federal income tax consequences that may be relevant to a stockholder in light of such stockholder’s particular circumstances or to stockholders subject to special rules, such as stockholders who received their Shares pursuant to the exercise of employee stock options or otherwise as compensation.

As used in this summary, a “U.S. holder” is any stockholder who is, for United States federal income tax purposes: (i) an individual who is a citizen or resident of the United States; (ii) a corporation (or other entity taxable as a corporation for United States federal income tax purposes) that is created or organized in or under the laws of the United States or of any political subdivision thereof; (iii) any estate the income of which is subject to United States federal income taxation regardless of its source; or (iv) any trust if a court within the United States is able to exercise primary supervision over the administration of the trust and one or more United States persons have the authority to control all substantial decisions of the trust, or if a valid election is in place to treat the trust as a United States person. As used in this summary, the term “non-U.S. holder” means any stockholder (other than an entity that is classified as a partnership under the Code) that is not, for United States federal income tax purposes, a U.S. holder.

If a partnership (including any entity or arrangement treated as a partnership for United States federal income tax purposes) holds Shares, the tax treatment of a partner in the partnership generally will depend upon the status of the partner and the activities of the partnership. Partners in a partnership holding Shares should consult their tax advisors regarding the tax consequences of the Offer and the Merger.

Because this discussion is intended to be a general summary only and individual circumstances may differ, each stockholder should consult its tax advisor to determine the applicability of the rules discussed below and the particular tax effects of the Offer and the Merger on a beneficial holder of Shares, including the application and effect of the alternative minimum tax and any state, local and foreign tax laws and of changes in such laws.

U.S. holders. The exchange of Shares for cash pursuant to the Offer or the Merger will be a taxable transaction for United States federal income tax purposes. In general, a U.S. holder who sells Shares pursuant to the Offer or receives cash in exchange for Shares pursuant to the Merger will recognize gain or loss for United States federal income tax purposes in an amount equal to the difference, if any, between the amount of cash received and the stockholder’s adjusted tax basis in the Shares sold pursuant to the Offer or exchanged for cash pursuant to the Merger. Gain or loss will be determined separately for each block of Shares (that is, Shares acquired at the same cost in a single transaction) tendered pursuant to the Offer or exchanged for cash pursuant to the Merger. Such gain or loss will be long-term capital gain or loss provided that a stockholder’s holding period for such Shares is more than one year at the time of consummation of the Offer or the Merger, as the case may be. Long-term capital gains recognized by individual and certain other non-corporate U.S. holders are generally taxed at preferential U.S. federal income tax rates. In the case of a Share that has been held for one year or less, such capital gains generally will be subject to tax at ordinary income tax rates. The deductibility of capital losses is subject to certain limitations.

Non-U.S. holders. A non-U.S. holder who tenders Shares pursuant to the Offer or receives cash in exchange for Shares pursuant to the Merger will not be taxed on any gain recognized on a disposition of Shares unless:

Backup withholding. A stockholder whose Shares are purchased in the Offer or exchanged for cash pursuant to the Merger may be subject to United States federal backup withholding at a rate of 28% unless certain information is provided to the Depositary or an exemption applies. See Section 3—“Procedures for Accepting the Offer and Tendering Shares—Backup Withholding.” Backup withholding is not an additional tax. Any amounts withheld under the backup withholding rules may be allowed as a refund or credit against a stockholder’s federal income tax liability provided that the required information is timely furnished to the IRS.

According to AMCOL’s Annual Report on Form 10-K for the fiscal year ended December 31, 2013, Shares are traded on the NYSE under the symbol “ACO.” The following table sets forth, for the periods indicated, the high and low sale prices per Share, as reported by the NYSE, and cash dividends declared per share. Share prices are as reported in AMCOL’s Form 10-K for the fiscal year ended December 31, 2013 and thereafter as reported on the NYSE based on published financial sources.

On February 11, 2014, the last full trading day prior to the public announcement of the recently terminated merger agreement among AMCOL, Imerys SA and Imerys Minerals Delaware, Inc., the last reported closing price per Share on the NYSE during normal trading hours was $36.72 per Share. On March 7, 2014, the last full trading day prior to the public announcement of the Merger Agreement, the last reported closing price per Share on the NYSE during normal trading hours was $46.66 per Share. On March 20, 2014, the last full trading day prior to the commencement of the Offer, the last reported closing price per Share on the NYSE during normal trading hours was $45.73 per Share. According to AMCOL’s Form 10-K for the fiscal year ended December 31,

2013, AMCOL has declared and paid cash dividends on the Shares for every year since 1938. Under the terms of the Merger Agreement, between the date of the Merger Agreement and the Effective Time, except as otherwise consented to by MTI in writing (which consent will not be unreasonably withheld, delayed or conditioned), AMCOL is not permitted to declare, authorize, set aside for payment or pay any dividends other than quarterly cash dividends not to exceed $.20 per Share and with declaration, record and payment dates at times consistent with historical practice over the prior two fiscal years, and, if a record date has not been set (in reference to a date consistent with such historical practice) prior to the Effective Time, no dividend shall be paid. See Section 14—“Dividends and Distributions.”

Before deciding whether to tender their Shares pursuant to the Offer, stockholders are urged to obtain a current market quotation for the Shares.

Assuming the requirements of Section 251(h) of the DGCL are satisfied, no stockholder vote to adopt the Merger Agreement or any other action by the stockholders of AMCOL will be required in connection with the Merger. Following the completion of the Offer and subject to the satisfaction or waiver of certain conditions, the Purchaser will be merged with and into AMCOL, and AMCOL will be the Surviving Corporation. The Certificate of Incorporation and the Bylaws of the Purchaser will be the Certificate of Incorporation and the Bylaws of the Surviving Corporation, until thereafter changed or amended. The Purchaser’s directors and officers immediately prior to the Effective Time will be the initial directors and officers of the Surviving Corporation until their successors have been elected or appointed.

NYSE Listing. The Shares are currently listed on the NYSE, but following the Effective Time the shares will no longer meet the requirements for continued listing on the NYSE because the only stockholder will be MTI. According to the published NYSE guidelines, the NYSE would consider delisting the Shares if, among other things, (i) the total number of holders of Shares falls below 400, (ii) the total number of holders of Shares falls below 1,200 and the average monthly trading volume for the Shares is less than 100,000 for the most recent 12 months or (iii) the number of publicly held Shares (exclusive of holdings of Shares held by officers or directors of AMCOL and their immediate families and other concentrated holdings of 10% or more) should fall below 600,000. Additionally, following consummation of the Offer MTI may cause AMCOL to take all action necessary to be treated as a “controlled company,” as defined by Section 303A.00 of the NYSE Listing Manual (or any successor provision), which means that AMCOL would be exempt from the requirement that the AMCOL Board be composed of a majority of “independent directors” and the related rules covering the independence of directors serving on the nominating and corporate governance committee and the compensation committee of the AMCOL Board. See Section 12—“Transaction Agreement—The Merger Agreement—Appointment of Directors after Acceptance for Payment of Shares Tendered in the Offer.”

Exchange Act Registration. The Shares currently are registered under the Exchange Act.

We intend to seek to cause AMCOL to apply for termination of the registration of Shares as soon as possible after consummation of the Offer if the requirements for termination of registration are met. Termination of the registration of Shares under the Exchange Act would reduce the information required to be furnished by AMCOL to its stockholders and to the SEC and would make certain provisions of the Exchange Act (such as the short-swing profit recovery provisions of Section 16(b), the requirement of furnishing a proxy statement or information statement in connection with stockholders’ meetings or actions in lieu of a stockholders’ meeting pursuant to Section 14(a) and 14(c) of the Exchange Act and the related requirement of furnishing an annual report to stockholders) no longer applicable with respect to Shares. In addition, if Shares are no longer registered under the Exchange Act, the requirements of Rule 13e-3 with respect to “going private” transactions would no longer be applicable to AMCOL. Furthermore, the ability of “affiliates” of AMCOL and persons holding “restricted securities” of AMCOL to dispose of such securities pursuant to Rule 144 under the Securities Act of 1933, as amended, may be impaired or eliminated. If the registration of Shares under the Exchange Act was terminated,

Shares would no longer be eligible for continued inclusion on the Board of Governors’ of the Federal Reserve System (the “Federal Reserve Board’s”) list of “margin securities” or eligible for stock exchange listing.

If the registration of Shares is not terminated prior to the Merger, then the registration of Shares under the Exchange Act will be terminated following completion of the Merger.

Margin Regulations. The Shares are currently “margin securities” under the regulations of the Federal Reserve Board, which has the effect, among other things, of allowing brokers to extend credit using such Shares as collateral. Depending upon factors similar to those described above regarding listing and market quotations, following the Offer, Shares may no longer constitute “margin securities” for the purposes of the margin regulations of the Federal Reserve Board, in which event the Shares would be ineligible as collateral for margin loans made by brokers.

The following description of AMCOL and its business has been taken from AMCOL’s Annual Report on Form 10-K for the fiscal year ended December 31, 2013, and is qualified in its entirety by reference to such report:

General. AMCOL is a leading international producer of specialty materials and related products and services for industrial and consumer markets. AMCOL operates in five segments: performance materials, construction technologies, energy services, transportation and corporate. AMCOL’s performance materials segment is a leading supplier of bentonite related products. AMCOL’s construction technologies segment provides products for non-residential construction, environmental and infrastructure projects worldwide. AMCOL’s energy services segment offers a range of patented technologies, products and services for both upstream and downstream oil and gas production. AMCOL’s transportation segment, which serves its domestic subsidiaries as well as third parties, is a dry van and flatbed carrier and freight brokerage service provider. AMCOL’s corporate segment includes the elimination of intersegment revenues as well as certain expenses associated with research and development, management, employee benefits and information technology activities. A significant portion of the products sold by AMCOL’s performance materials segment and, to a lesser extent, its construction technologies segment, utilize a mineral called bentonite. Bentonite has several valuable characteristics, including its ability to bind, swell, adsorb, control rheology, soften fabrics, and have its surface modified through chemical and physical reactions. AMCOL also develops applications for other specialty minerals, most significantly chromite and leonardite. AMCOL earns revenues from the sale of finished products, provision of services, rental of equipment, and charges for shipping goods and materials to customers. Its service revenues are derived primarily from its construction technologies, energy services, and transportation segments; its transportation segment is purely service based.

AMCOL is a Delaware corporation with its principal executive offices located at 2870 Forbs Avenue, Hoffman Estates, IL 60192. The telephone number for AMCOL is (847) 851-1500.

Available Information. AMCOL is subject to the information and reporting requirements of the Exchange Act and in accordance therewith is obligated to file reports and other information with the SEC relating to its business, financial condition and other matters. Certain information, as of particular dates, concerning AMCOL’s business, principal physical properties, capital structure, material pending litigation, operating results, financial condition, directors and officers (including their remuneration and equity awards granted to them), the principal holders of AMCOL’s securities, any material interests of such persons in transactions with AMCOL and other matters is required to be disclosed in proxy statements and periodic reports distributed to AMCOL’s stockholders and filed with the SEC. Such reports, proxy statements and other information should be available for inspection at the public reference room at the SEC’s office at 100 F Street, N.E., Washington, D.C. 20549-0213. Copies may be obtained by mail, upon payment of the SEC’s customary charges, by writing to its principal office at 100 F Street, N.E., Washington, D.C. 20549-0213. Further information on the operation of the SEC’s Public

Reference Room in Washington, D.C. can be obtained by calling the SEC at (800) SEC-0330. The SEC also maintains an Internet web site that contains reports, proxy statements and other information about issuers, such as AMCOL, who file electronically with the SEC. The address of that site is http://www.sec.gov. AMCOL also maintains an Internet website at http://www.amcol.com. The information contained in, accessible from or connected to AMCOL’s website is not incorporated into, or otherwise a part of, this Offer to Purchase or any of AMCOL’s filings with the SEC. The website addresses referred to in this paragraph are inactive text references and are not intended to be actual links to the websites.

Sources of Information. Except as otherwise set forth herein, the information concerning AMCOL contained in this Offer to Purchase has been based upon publicly available documents and records on file with the SEC and other public sources. Although we have no knowledge that any such information contains any misstatements or omissions, none of MTI, the Purchaser or any of their respective affiliates or assigns, the Information Agent, the Dealer Manager or the Depositary assumes responsibility for the accuracy or completeness of the information concerning AMCOL contained in such documents and records or for any failure by AMCOL to disclose events which may have occurred or may affect the significance or accuracy of any such information.

Certain Projections. In a presentation to MTI management, AMCOL provided MTI with selected unaudited projected financial information concerning AMCOL. Such information is described in AMCOL’s Schedule 14D-9, which will be filed with the SEC and is being mailed to AMCOL’s stockholders with this Offer to Purchase. AMCOL’s stockholders are urged to, and should, carefully read the Schedule 14D-9. AMCOL has advised MTI that the unaudited prospective financial information was not prepared with a view toward public disclosure, and the inclusion of such information in AMCOL’s Schedule 14D-9 should not be regarded as an indication that any of MTI, AMCOL, their respective financial advisors or any other recipient of this information considered, or now considers, it to be necessarily predictive of actual future results. The unaudited prospective financial information was not included in AMCOL’s Schedule 14D-9 in order to influence any stockholder to make any investment decision with respect to the Offer or the Merger, including whether to tender Shares in the Offer or whether to seek appraisal rights with respect to the Shares. AMCOL has advised us that, while presented with numerical specificity, the unaudited prospective financial information reflects numerous estimates and assumptions with respect to matters such as industry performance and competition, general business, economic and geopolitical conditions and additional matters specific to AMCOL’s business, all of which are difficult to predict and many of which are beyond AMCOL’s control. AMCOL also advised us that the unaudited prospective financial information was, in general, prepared primarily for internal use and is subjective in many respects. As a result, there can be no assurance that the prospective results will be realized or that actual results will not be significantly higher or lower than estimated. Since the unaudited prospective financial information covers multiple years, such information by its nature becomes less predictive with each successive year. AMCOL’s stockholders are urged to review AMCOL’s most recent SEC filings for a description of risk factors with respect to AMCOL’s business. In addition, AMCOL has advised us that the unaudited prospective financial information was not prepared with a view toward complying with United States generally accepted accounting principles, the published guidelines of the SEC regarding projections or the guidelines established by the American Institute of Certified Public Accountants for preparation and presentation of prospective financial information. Neither AMCOL’s independent registered public accounting firm, MTI’s independent registered public accounting firm nor any other independent accountants, have compiled, examined, or performed any procedures with respect to the unaudited prospective financial information contained therein, nor have they expressed any opinion or any other form of assurance on such information or its achievability. Furthermore, the unaudited prospective financial information does not take into account any circumstances or events actually occurring after the date it was prepared.

General. The Purchaser is a Delaware corporation with its principal offices located at c/o Minerals Technologies Inc., 622 Third Avenue, 38th Floor, New York, New York 10017. The telephone number of the Purchaser is (212) 878-1800. The Purchaser is a wholly owned subsidiary of MTI. The Purchaser was formed for

the purpose of making a tender offer for all of the Shares of AMCOL and has not engaged, and does not expect to engage, in any business other than in connection with the Offer and the Merger.

MTI is a Delaware corporation with its principal offices located at 622 Third Avenue, 38th Floor, New York, New York 10017. The telephone number of MTI is (212) 878-1800.

The name, citizenship, business address, business phone number, present principal occupation or employment and past material occupation, positions, offices or employment for at least the last five years for each director and each of the executive officers of MTI and the Purchaser and certain other information are set forth in Schedule I hereto.

During the last five years, none of MTI or the Purchaser or, to the best knowledge of MTI and the Purchaser, any of the persons listed in Schedule I hereto (i) has been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors) or (ii) was a party to any judicial or administrative proceeding (except for matters that were dismissed without sanction or settlement) that resulted in a judgment, decree or final order enjoining the person from future violations of, or prohibiting activities subject to, federal or state securities laws, or a finding of any violation of such laws.

Except as described in this Offer to Purchase and Schedule I hereto, (i) none of MTI, the Purchaser, any majority-owned subsidiary of MTI or, to the best knowledge of MTI and the Purchaser, any of the persons listed in Schedule I hereto or any associate or any of the persons so listed beneficially owns or has any right to acquire, directly or indirectly, any Shares and (ii) none of MTI, the Purchaser or, to the best knowledge of MTI and the Purchaser, any of the persons or entities referred to above nor any director, executive officer or subsidiary of any of the foregoing has effected any transaction in the Shares during the past 60 days. As of the date hereof, MTI beneficially owns of record 100 Shares. These Shares were purchased through an ordinary brokerage transaction on the open market on February 27, 2014 for an average price of $44.88 per share.

Except as provided in the Merger Agreement or as otherwise described in this Offer to Purchase, none of MTI, the Purchaser or, to the best knowledge of MTI and the Purchaser, any of the persons listed in Schedule I hereto, has any contract, arrangement, understanding or relationship with any other person with respect to any securities of AMCOL, including any contract, arrangement, understanding or relationship concerning the transfer or voting of such securities, finder’s fees, joint ventures, loan or option arrangements, puts or calls, guarantees of loans, guarantees against loss, guarantees of profits, division of profits or loss or the giving or withholding of proxies.

Except as set forth in this Offer to Purchase, none of MTI, the Purchaser or, to the best knowledge of MTI and the Purchaser, any of the persons listed on Schedule I hereto, has had any business relationship or transaction with AMCOL or any of its executive officers, directors or affiliates that is required to be reported under the rules and regulations of the SEC applicable to the Offer. Except as set forth in this Offer to Purchase, there have been no contacts, negotiations or transactions between MTI or any of their subsidiaries or, to the best knowledge of MTI, any of the persons listed in Schedule I hereto, on the one hand, and AMCOL or its affiliates, on the other hand, concerning a merger, consolidation or acquisition, tender offer or other acquisition of securities, an election of directors or a sale or other transfer of a material amount of assets during the past two years.

Available Information. Pursuant to Rule 14d-3 under the Exchange Act, MTI and the Purchaser filed with the SEC a Tender Offer Statement on Schedule TO (the “Schedule TO”), of which this Offer to Purchase forms a part, and exhibits to the Schedule TO. The Schedule TO and the exhibits thereto can be inspected and copied at the public reference facilities maintained by the SEC at 100 F Street, N.E., Washington, D.C. 20549-0213. Information regarding the public reference facilities may be obtained from the SEC by telephoning (800) SEC-0330. MTI filings are also available to the public on the SEC’s internet site (http://www.sec.gov). Copies of such materials may also be obtained by mail from the Public Reference Section of the SEC at 100 F Street, N.E., Washington, D.C. 20549-0213 at prescribed rates.

The Offer is not conditioned upon the Purchaser or MTI obtaining financing to fund the purchase of Shares pursuant to the Offer and the Merger. Because (i) the only consideration to be paid in the Offer and the Merger is cash, (ii) the Offer is to purchase all issued and outstanding Shares, (iii) if the Offer is consummated, then we will acquire all remaining Shares for the same per Share cash price in the Merger (subject to certain appraisal rights under Section 262 of the DGCL), (iv) there is no financing condition to the completion of the Offer, and (v) we and MTI have cash on hand and committed debt financing that will be sufficient to finance the payments to be made in the Offer and the Merger, we believe the financial condition of MTI and the Purchaser is not material to a decision by a holder of Shares whether to sell, hold or tender Shares pursuant to the Offer.

MTI and the Purchaser estimate that the total funds required to purchase all issued and outstanding Shares pursuant to the Offer and to complete the Merger pursuant to the Merger Agreement will be approximately $1,954,000,000, including related transaction fees and expenses and refinancing of indebtedness. MTI will provide the Purchaser with sufficient funds to pay for all Shares accepted for payment in the Offer or to be acquired in the Merger.

In connection with MTI’s entry into the Merger Agreement, MTI, JPMorgan Chase Bank, N.A. (“JPMCB”) and J.P. Morgan Securities LLC (“JPMS”) entered into a debt commitment letter (the “Debt Commitment Letter”), dated March 6, 2014. The Debt Commitment Letter provides an aggregate of $1,760,000,000 in committed debt financing to MTI, consisting of a $1,560,000,000 senior secured term loan facility, the proceeds of which will be used, together with cash on hand, to finance the purchase of the Shares in the Offer, to consummate the Existing Indebtedness Transactions (as defined below) and to pay fees and expenses incurred in connection with the Transactions and the Existing Indebtedness Transactions, and a $200,000,000 senior secured revolving facility, the proceeds of which will be available for working capital and other general corporate purposes.

MTI may invite other banks, financial institutions and institutional lenders to participate in the debt financing described in the Debt Commitment Letter and to undertake a portion of the commitments to provide such debt financing.

Senior Secured Facilities. Interest under the senior secured revolving facility is expected to be payable either, at the option of MTI, at a base rate (based on the higher of JPMCB’s prime rate, the federal funds effective rate plus 0.50% and adjusted LIBOR for an interest period of one month plus 1.00%) plus a margin of 0.75% or an adjusted LIBOR-based rate (or, in the case of borrowings in certain foreign currencies, a similar rate) plus a margin of 1.75% and will be payable at the end of each interest period to be set forth in a definitive credit agreement (but at least every three months). In addition, the interest rate margins under the senior secured revolving facility will be subject to decreases of up to 0.25% per annum, based on the ratio of MTI’s total consolidated debt, less unrestricted cash and cash equivalents, to consolidated EBITDA (the “Net Leverage Ratio”) at the end of each fiscal quarter. Interest under the senior secured term loan facility is expected to be payable either, at the option of MTI, at the base rate described above plus a margin ranging from 1.25% to 1.75% (based on the corporate credit ratings of MTI determined by Standard & Poor’s Financial Services LLC and Moody’s Investors Service, Inc. (collectively, the “Ratings”)) or the adjusted LIBOR-based rate described above (subject to, in the case of the senior secured term facility, a floor of 0.75% per annum) plus a margin ranging from 2.25% to 2.75% (based on the Ratings) and will be payable at the end of each interest period to be set forth in a definitive credit agreement (but at least every three months). In addition, the interest rate margins under the senior secured term loan facility will be subject to a decrease of 0.25%, based on the Net Leverage Ratio at the end of each fiscal quarter.

The borrower under the senior secured facilities will be MTI. The senior secured facilities are expected to be guaranteed on a joint and several basis by all of the existing and future direct and indirect domestic subsidiaries of MTI other than certain immaterial subsidiaries and subject to certain other exceptions and restrictions imposed by applicable law. The senior secured facilities are expected to be secured, subject to permitted liens and other agreed upon exceptions, by a first-priority security interest in substantially all the assets of MTI and each subsidiary guarantor, including personal property, certain owned real property and all the share capital held by MTI and each subsidiary guarantor, including the stock of AMCOL, with certain exceptions, including limitations on the pledge of capital stock of foreign subsidiaries.

The senior secured facilities contemplated by the Debt Commitment Letter are subject to certain closing conditions, including, without limitation:

The Debt Commitment Letter will terminate if (a) the initial funding under the senior secured facilities does not occur on or prior to September 17, 2014, (b) the Offer is consummated without the use of the senior secured facilities or (c) the Merger Agreement is terminated without the closing of the Offer and the funding of the senior secured facilities.

Subject to the terms and conditions of the Merger Agreement, MTI will use its reasonable best efforts to obtain the Financing (as defined in the Merger Agreement) on the terms and conditions described in the Debt Commitment Letter and will not, subject to certain exceptions, permit any amendment or modification to be made to, or any waiver of any provision or remedy under, the Debt Commitment Letter if such amendment, modification or waiver would (a) reduce the aggregate amount of the Financing below the amount that would be required to consummate the Transactions (as defined in the Merger Agreement) or (b) impose new or additional conditions or otherwise amend, modify or expand any conditions to the receipt of the Financing that would reasonably be expected to (i) materially delay or prevent the ability of MTI to consummate the Transactions, (ii) make the funding of the Financing (or satisfaction of the conditions to obtaining the Financing) materially less likely to occur or (iii) adversely impact the ability of MTI or the Purchaser to enforce its rights against the other parties to the Debt Commitment Letter or the definitive agreements with respect thereto. See Section 12—“Transaction Agreement—The Merger Agreement—Financing.”

As of the date of this Offer to Purchase, no alternative financing arrangements or alternative financing plans have been made in the event the debt financing described in this Offer to Purchase is not available as anticipated.

The following is a description of contacts between representatives of MTI or the Purchaser with representatives of AMCOL that resulted in the execution of the Merger Agreement and the agreements related to the Offer. For a review of AMCOL’s activities relating to these contacts, please refer to AMCOL’s Schedule 14D-9 being mailed to stockholders with this Offer to Purchase.

MTI regularly evaluates various strategic alternatives to improve its competitive position and enhance value for MTI stockholders. This includes opportunities for acquisitions of other companies or their assets.

In April 2010, Joseph Muscari, the Chairman and Chief Executive Officer of MTI, met with AMCOL’s then Chief Executive Officer Larry Washow, in Hoffman Estates, Illinois, during which Mr. Muscari proposed to Mr. Washow that MTI and AMCOL should discuss the possibility of a business combination between the two

companies. This led to a meeting in May 2010 in Pittsburgh, Pennsylvania between Mr. Washow, Ryan McKendrick, then AMCOL’s Chief Operating Officer, Gary Castagna, then the President of AMCOL’s Minerals segment, and Don Pearson, AMCOL’s Chief Financial Officer, on the one hand, and Mr. Muscari, John Sorel, then the Chief Financial Officer of MTI, Thomas Meek, MTI’s General Counsel, and Doug Dietrich, then MTI’s Vice President, Corporate Development, on the other hand, to further explore the possibility of a business combination between the two companies. During this time, the parties did not reach agreement on a potential business combination transaction.

During October and November of 2012, representatives of MTI and AMCOL engaged in renewed discussions initiated by MTI regarding a potential business combination transaction. During those discussions, MTI proposed a stock-for-stock transaction to combine the businesses of AMCOL and MTI. During this time, the parties did not reach agreement on a potential business combination transaction.

On October 28, 2013, Joseph Muscari, the Executive Chairman of MTI at the time, called Ryan McKendrick, AMCOL’s Chief Executive Officer, to request a meeting on the following day with Mr. McKendrick and John Hughes, the Chairman of the AMCOL Board, in order to present an offer to acquire AMCOL.

The following day, on October 29, 2013, a meeting was held in Tampa, Florida between Mr. Hughes, Mr. McKendrick and Don Pearson, AMCOL’s Chief Financial Officer, on the one hand, and Mr. Muscari, Doug Dietrich, MTI’s Chief Financial Officer, and Jon Hastings, MTI’s Senior Vice President, Corporate Development, on the other hand. During the meeting, Mr. Muscari expressed MTI’s preliminary interest in acquiring AMCOL and handed to the representatives of AMCOL a letter proposing an acquisition of all of AMCOL’s outstanding shares at a price of $40.50 per share. Mr. Muscari also indicated to Mr. McKendrick that MTI was considering paying for AMCOL’s shares one-third in MTI stock and two-thirds in cash.

On October 31, 2013, Mr. McKendrick called Mr. Muscari and communicated that the AMCOL Board had directed the management team to review MTI’s proposal. In order to do that effectively, Mr. McKendrick proposed that the parties negotiate and execute a confidentiality agreement, and that the parties meet to discuss AMCOL’s business, key initiatives and the potential benefits of a combination.

On November 6, 2013, MTI and AMCOL entered into a standstill and non-disclosure agreement, the standstill provision of which would terminate upon AMCOL’s entry into a binding definitive agreement with any third party to acquire AMCOL.

On November 7, 2013, a meeting was held at the offices of Kirkland & Ellis LLP (“Kirkland & Ellis”), AMCOL’s outside legal counsel, in Chicago attended by executive officers of AMCOL and MTI and their respective financial and legal advisors. The discussion focused on the respective businesses of MTI and AMCOL and the potential benefits of a business combination between the two companies.

On November 18, 2013, Mr. McKendrick called Mr. Muscari to discuss MTI’s proposal. During the discussion, Mr. McKendrick communicated to Mr. Muscari that the price of $40.50 was inadequate and that it was the position of the AMCOL Board that any proposal should allow AMCOL’s stockholders to receive an increased cash component and the AMCOL Board’s preference was for an all-cash transaction.

On November 19, 2013, Mr. Muscari called Mr. McKendrick to convey that, depending on other terms of the proposed transaction, MTI had some flexibility to increase the cash component of the merger consideration provided in MTI’s offer, but MTI did not revise the offer at that time.

On November 22, 2013, Mr. McKendrick called Mr. Muscari and told him that the AMCOL Board had decided to advance the discussions with MTI but that the AMCOL Board did not believe that MTI’s current proposal appropriately valued AMCOL or properly reflected the value that a combination would bring to MTI.

Mr. McKendrick further expressed that AMCOL was prepared to share its financial projections with MTI so that it could better appreciate AMCOL’s prospects and potential. Mr. McKendrick also told Mr. Muscari that AMCOL’s management team would be available for an in-person meeting to discuss the financial projections and key transaction information, and that, following such a meeting, AMCOL would ask MTI to return in short order and provide its best and final revised proposal. Finally, Mr. McKendrick told Mr. Muscari that the AMCOL Board was focused on an all-cash or substantially all-cash transaction, which should be reflected in any revised proposal.

On December 3, 2013, representatives of AMCOL and MTI met at the New York City offices of Cravath, Swaine & Moore LLP (“Cravath”), MTI’s outside legal counsel, to discuss AMCOL’s business plan and key growth initiatives. During the meeting, representatives of AMCOL asked representatives of MTI to submit their revised proposal in short order.

On December 10, 2013, Mr. McKendrick and Mr. Pearson held a conference call with members of MTI’s management team to answer follow-up questions.

On December 13, 2013, MTI delivered a letter to AMCOL increasing its offer to $41.00 per share, with the merger consideration comprised of $8.20 in MTI stock and $32.80 in cash. The proposal included a request for a 45 business day period of exclusivity to finalize negotiations.

On December 16, 2013, representatives of Goldman, Sachs & Co. (“Goldman Sachs”), AMCOL’s financial advisor, called representatives of Lazard Frères & Co. LLC (“Lazard”), MTI’s financial advisor, to express disappointment with the modest improvement to the terms of MTI’s offer, to seek additional information about the confirmatory due diligence that MTI planned to conduct on AMCOL and the reverse due diligence that AMCOL would need to conduct on MTI if MTI’s consideration included stock, and to discuss MTI’s plans for financing its offer and MTI’s request for exclusivity. Representatives of Lazard later communicated that MTI did not want to incur additional due diligence expenses through the engagement of external resources until AMCOL had completed its market check process and was prepared to enter into exclusivity with MTI.

On December 18, 2013, Mr. McKendrick called Mr. Muscari to communicate that the AMCOL Board was evaluating MTI’s revised proposal of $41.00 per share in cash and stock and emphasized the importance of both companies completing due diligence on each other promptly. Mr. McKendrick also told Mr. Muscari that while the AMCOL Board would consider granting a short exclusivity period under appropriate circumstances in the future, it was not prepared to grant exclusivity at this time, because it was in AMCOL’s interest to retain the flexibility to conduct a market check.

On December 23, 2013, Mr. McKendrick called Mr. Muscari and communicated that the AMCOL Board was willing to proceed with due diligence on the basis of the $41.00 per share value included in MTI’s proposal. Mr. McKendrick reiterated the preference of the AMCOL Board for an all-cash transaction and noted that, if the proposal would contain a stock component, it was important for AMCOL to have an opportunity to perform due diligence on MTI.

On December 24, 2013, representatives of Lazard called representatives of Goldman Sachs and reiterated that MTI did not want to incur additional due diligence expenses through the engagement of external resources until AMCOL had completed its market check process and was prepared to enter into exclusivity with MTI.

During the week of December 30, 2013, representatives of Goldman Sachs and Kirkland & Ellis engaged in additional discussions with MTI and its advisors on due diligence and process issues. At this time, MTI reiterated

its position to AMCOL that it did not want to incur further external due diligence expenses without having obtained exclusivity.

On January 7, 2014, a representative of Cravath sent a draft exclusivity letter to representatives of Kirkland & Ellis. The letter contemplated a 30-day period (from mid-January to mid-February) during which AMCOL would not be permitted to engage in discussions with, or provide information to, parties other than MTI but permitted either party to terminate the letter at any time prior to January 31, 2014 on two business days’ notice.

Also on January 7, 2014, AMCOL sent a reverse due diligence request list to MTI.

On January 8, 2014, AMCOL and its financial advisors held a telephonic conference with MTI and its financial advisors to discuss MTI’s due diligence request list.

Also on January 8, 2014, representatives of Kirkland & Ellis responded to representatives of Cravath that AMCOL would consider entering into a modified exclusivity agreement that, from January 15, 2014 to January 31, 2014, prohibited AMCOL from sending a merger agreement or other definitive transaction documentation to any party other than MTI but which otherwise permitted AMCOL to solicit proposals and provide information to, and engage in discussions with, parties other than MTI. Under the agreement, after January 31, 2014, AMCOL would be prohibited for two weeks from providing information to, or engaging in discussions with, parties other than MTI. The modified exclusivity agreement would retain the right of either party to terminate such modified exclusivity agreement by providing two business days’ prior written notice through January 31, 2014.

On January 9, 2014, representatives of Kirkland & Ellis called representatives of Cravath to communicate the AMCOL Board’s opposition to entering into exclusivity on the terms proposed by MTI but to confirm that AMCOL was willing to enter into a modified exclusivity agreement on terms consistent with those previously proposed by Kirkland & Ellis, which would allow MTI a first opportunity to negotiate a merger agreement with AMCOL.

On January 10, 2014, Mr. Muscari called Mr. McKendrick to inform him that MTI would consider walking away from the proposed deal if exclusivity were not granted.

On January 11, 2014, AMCOL opened an electronic data room and provided access to MTI and its representatives.

Also on January 11, 2014, representatives of Kirkland & Ellis sent representatives of Cravath a draft merger agreement that reflected the AMCOL Board’s preference for an all-cash transaction.

On January 14, 2014, AMCOL and MTI entered into a modified exclusivity agreement reflecting the terms discussed on the January 8, 2014 call between Kirkland & Ellis and Cravath.

On January 16 and 18, 2014, representatives of Goldman Sachs sent Lazard and MTI draft due diligence schedules relating to site visits to be carried out by MTI, with a plan to conduct the majority of site visits in the last week of January 2014.

On January 19, 2014, MTI proposed a revised site visit schedule and representatives of Goldman Sachs and representatives of Lazard discussed such schedule and representatives of Goldman Sachs encouraged Lazard to ask MTI to accelerate its timing for site visits.

On January 24, 2014, MTI responded with selected questions on AMCOL’s reverse due diligence request list, but did not provide MTI’s financial projections as requested by AMCOL. On January 27, 2014, representatives of MTI communicated that MTI was unwilling to provide financial projections until AMCOL was fully exclusive with MTI.

During the week of January 27, 2014, MTI’s consultants reviewed mining-related information at AMCOL’s office in Belle Fourche, South Dakota, visited AMCOL’s mines in Colony, Wyoming and conducted a site visit in South Africa.

On January 30, 2014, representatives of MTI confirmed to representatives of AMCOL that the $41.00 offer from MTI, comprised of $8.20 in MTI stock and $32.80 in cash, both in terms of value and the consideration mix, was MTI’s best and final offer.

On January 31, 2014, a representative of Kirkland & Ellis sent a notice of termination by AMCOL of the modified exclusivity agreement between MTI and AMCOL to a representative of Cravath.

On February 1, 2014, Mr. McKendrick returned a phone call from Mr. Muscari. During the conversation, when asked why the MTI offer was not acceptable to AMCOL, Mr. McKendrick responded that the AMCOL Board continued to find a partial stock offer inferior to an all-cash offer and that, since the MTI offer was “best and final,” the AMCOL Board determined to proceed towards a definitive agreement with a third party.

On February 2, 2014, AMCOL suspended MTI’s access to the electronic data room.

On the morning of February 3, 2014, MTI submitted a revised written proposal to acquire all of the outstanding shares AMCOL’s common stock for $41.00 per share in cash. The proposal contemplated that AMCOL’s stockholders would be permitted at their discretion to elect to receive up to 20% of the consideration in MTI’s stock. In light of AMCOL’s exclusivity agreement with a third party, a representative of Kirkland & Ellis informed a representative of Cravath that AMCOL was unable to respond to MTI’s latest proposal.

On February 11, 2014, MTI sent a letter to AMCOL restating its proposal to acquire all of the outstanding Shares of AMCOL for $41.00 per Share in cash, subject to completion of its due diligence and the negotiation of mutually satisfactory definitive agreements, and attaching an executed financing commitment letter from MTI’s lead lender that was subject to due diligence.

On February 12, 2014, each of AMCOL and Imerys issued a press release to announce that they had signed a definitive merger agreement on February 11, 2014 (the “Imerys Merger Agreement”), pursuant to which, after the completion of the tender offer described therein and the satisfaction or waiver of certain conditions, a wholly owned subsidiary of Imerys would be merged with and into AMCOL, with AMCOL continuing as the surviving corporation and a wholly owned subsidiary of Imerys. Under the terms of the Imerys Merger Agreement, the offer price was $41.00 per Share in cash.

On February 13, 2014, the day after the transaction between AMCOL and Imerys was announced, MTI sent a letter to Mr. Hughes and Mr. McKendrick offering, subject to further due diligence, to acquire all of AMCOL’s outstanding Shares for $42.00 per Share in cash.

Later on February 13, 2014, AMCOL provided access to its electronic data room to MTI and its representatives, which access continued until February 26, 2014.

On February 14, 2014, MTI issued a press release confirming that it had made a proposal to acquire all of AMCOL’s outstanding Shares for $42.00 per Share in cash.

Over the following days, AMCOL and its representatives facilitated due diligence by MTI, including by arranging management meetings.

On February 21, 2014, the board of directors of MTI held a meeting at which it granted approval and authority for MTI’s management to make binding proposals to AMCOL to acquire all of AMCOL’s outstanding Shares.

On February 24, 2014, MTI sent to AMCOL a revised, unsolicited proposal to acquire all of AMCOL’s outstanding Shares at a price per Share of $42.50 in cash (the “Revised MTI Proposal”). The Revised MTI Proposal included a proposed merger agreement and a financing commitment letter. The proposed merger agreement provided that MTI or AMCOL could terminate the merger agreement if the proceeds of the financing were not available to MTI in an amount sufficient, together with its other available cash, to enable MTI to consummate the acquisition. In such a circumstance, MTI would have been obligated to pay AMCOL a $70 million reverse termination fee, and AMCOL would not have had a right of specific performance to require MTI to complete the transaction.

On February 25, 2014, representatives of Kirkland & Ellis and Goldman Sachs had a conference call with representatives of Cravath and Lazard regarding the Revised MTI Proposal, communicated the concerns of the AMCOL Board and requested that MTI reconsider the need for the termination right and limitation on AMCOL’s right of specific performance described above. Later that evening, a representative of Cravath communicated to a representative of Kirkland & Ellis that MTI was not agreeable to modifying the termination right and remedies structure reflected in the Revised MTI Proposal.

On February 26, 2014, AMCOL and Imerys issued separate press releases announcing the amendment of the Imerys Merger Agreement and the increased offer price of $42.75 per Share in cash contemplated thereby.

On March 3, 2014, MTI sent to AMCOL a revised, unsolicited proposal to acquire all of AMCOL’s outstanding Shares at a price per Share of $45.00 in cash (the “Second Revised MTI Proposal”). The Second Revised MTI Proposal included a proposed merger agreement with terms substantially identical to those in the proposed merger agreement included in the Revised MTI Proposal, except that the offer price was increased from $42.50 to $45.00 per Share. In addition, the Second Revised MTI Proposal included a financing commitment letter also containing terms substantially identical to those in the Revised MTI Proposal, except that the amount of the debt facilities was increased to accommodate the higher aggregate offer price.

On the evening of March 3, 2014, representatives of Kirkland & Ellis discussed the Second Revised MTI Proposal with representatives of Cravath and reiterated the AMCOL Board’s concerns with MTI’s termination right related to its failure to obtain financing and the absence of a specific performance remedy for AMCOL in the Second Revised MTI Proposal.

On March 4, 2014, a representative of Cravath called a representative of Kirkland & Ellis to report that MTI had determined to revise further its proposal (the “Third Revised MTI Proposal”) to provide AMCOL with the right to specifically enforce MTI’s obligation to close the transaction. MTI also proposed to remove those provisions in MTI’s previous proposed merger agreement that would have made the transaction contingent on MTI’s receipt of sufficient financing for the transaction pursuant to MTI’s commitment letter with its lenders and that provided, in lieu of such specific enforcement remedy, for the payment by MTI of a reverse break-up fee to AMCOL if such financing were not obtained. The other terms of the Third Revised MTI Proposal, including the offer price of $45.00 per Share, were otherwise identical to the terms contained in the Second Revised MTI Proposal. Shortly thereafter, a representative of Cravath sent to a representative of Kirkland & Ellis a revised proposed merger agreement reflecting the terms of the Third Revised MTI Proposal.

Later on March 4, 2014, AMCOL and Imerys issued separate press releases announcing the second amendment to the Imerys Merger Agreement and the increased offer price of $45.25 per Share in cash contemplated thereby.

Early in the morning on March 6, 2014, MTI sent to AMCOL a revised, unsolicited proposal to acquire all of AMCOL’s outstanding Shares at a price per Share of $45.75 in cash (the “Fourth Revised MTI Proposal”). The Fourth Revised MTI Proposal included a proposed merger agreement with terms substantially identical to those in the proposed merger agreement included in the Third Revised MTI Proposal, except that the offer price was increased from $45.00 to $45.75. In addition, the Fourth Revised MTI Proposal included a financing commitment letter also containing terms substantially identical to those in the Third Revised MTI Proposal, except that the amount of the debt facilities was increased to accommodate the higher aggregate offer price.

Later on March 6, 2014, MTI received a notice from AMCOL advising MTI that the AMCOL Board had determined in good faith, after consultation with its outside legal counsel and financial advisors, that the Fourth Revised MTI Proposal constituted a Superior Proposal (as defined in the Imerys Merger Agreement), and had determined to notify Imerys of AMCOL’s intention to terminate the Imerys Merger Agreement (as amended) pursuant to Section 8.1(d)(ii) thereof should Imerys not make such modifications to the terms and conditions thereof prior to the end of the Notice Period (as defined therein) so that the Imerys Merger Agreement, as so modified, results in a transaction no less favorable to the stockholders of AMCOL than the Fourth Revised MTI Proposal. AMCOL issued a press release to that effect that night.

On March 7, 2014, Imerys issued a press release stating that it had determined not to increase its offer price of $45.25 per Share in cash as set forth in the second amendment to the Imerys Merger Agreement.

During the period from March 7, 2014 to March 10, 2014, the respective representatives of MTI and AMCOL participated in discussions to finalize matters relating to the Merger Agreement.

On March 9, 2014, the board of directors of MTI unanimously approved the execution of the Merger Agreement, the transactions contemplated thereby, the financing described in this Offer to Purchase and certain related ancillary matters.

On the morning of March 10, 2014, concurrently with the termination of the Imerys Merger Agreement, MTI and AMCOL entered into the Merger Agreement, which had been unanimously approved by both companies’ boards, and AMCOL paid a termination fee of $39,000,000 to a subsidiary of Imerys. Later that morning, MTI and AMCOL issued a joint press release describing the proposed transaction between MTI and AMCOL.

On March 21, 2014, the Purchaser commenced the Offer. During the Offer, MTI and the Purchaser intend to have ongoing contacts with AMCOL and its directors, officers and stockholders.

The following is a summary of certain provisions of the Merger Agreement. The following description of the Merger Agreement and the transactions contemplated thereby is subject to, and qualified in its entirety by, the full text of the Merger Agreement, a copy of which is attached as an exhibit to the Schedule TO and is incorporated herein by reference. For a further understanding of the Merger Agreement, you are encouraged to read the full text of the Merger Agreement. The Merger Agreement has been attached to provide investors with information regarding its terms. It is not intended to provide any other factual information about AMCOL, MTI or the Purchaser, their respective businesses, or the actual conduct of their respective businesses during the period prior to the consummation of the Merger. The Merger Agreement contains representations and warranties that are the product of negotiations among the parties thereto and that the parties made to, and solely for the benefit of, each other as of specified dates. The assertions embodied in those representations and warranties are subject to qualifications and limitations agreed to by the respective parties and are also qualified in important part by confidential disclosure schedules delivered in connection with the Merger Agreement. The representations and warranties may have been made for the purpose of allocating contractual risk between the parties to the agreements instead of establishing these matters as facts, and may be subject to standards of materiality applicable to the contracting parties that differ from those applicable to investors. None of the stockholders of AMCOL or any other third parties should rely on the representations, warranties and covenants or any descriptions thereof as characterizations of the actual state of facts or conditions of MTI, the Purchaser, AMCOL or any of their respective subsidiaries or affiliates. Capitalized terms used in this Section 12—“The Transaction Agreements” and not otherwise defined have the respective meanings assigned thereto in the Merger Agreement.

The Offer. The Merger Agreement provides that Purchaser will (and that MTI will cause Purchaser to) commence the Offer as promptly as practicable but in no event more than ten business days after the date of the Merger Agreement. The obligations of the Purchaser, and of MTI to cause the Purchaser, to consummate the Offer in accordance with its terms, and to promptly accept for payment and pay for all Shares validly tendered and not validly withdrawn pursuant to the Offer will be subject to the satisfaction or waiver by the Purchaser of the conditions (the “Offer Conditions”) described in Section 15—“Conditions of the Offer.” The Purchaser expressly reserves the right, at any time, in its sole discretion, to waive any Offer Condition in whole or in part, or to modify the terms of the Offer; provided, however, without the prior written consent of AMCOL, the Purchaser will not (i) decrease the Offer Price, except in the case of certain agreed upon equitable adjustments, (ii) change the form of consideration payable in the Offer, (iii) decrease the maximum number of Shares sought to be purchased in the Offer, (iv) amend or modify any of the Offer Conditions in a manner that adversely affects holders of Shares generally, (v) change the Minimum Condition, (vi) impose conditions to the Offer in addition to the Offer Conditions, (vii) extend or otherwise change the Expiration Date in a manner other than as required or permitted by the Merger Agreement, or (viii) provide for a “subsequent offering period” (or any extension thereof) in accordance with Rule 14d-11 under the Exchange Act.

The Offer is initially scheduled to expire at 9:00 a.m., New York City time, on April 18, 2014, which is twenty-one business days after the commencement of the Offer. The Offer shall be extended from time to time as follows: (i) if, on the scheduled Expiration Date, the Minimum Condition has not been satisfied or any of the other Offer Conditions has not been satisfied, or waived by MTI or the Purchaser if permitted under the Merger Agreement, then the Purchaser shall extend the Offer for one or more periods of not more than five business days each (or of not more than ten business days each if the only Offer Condition(s) not yet satisfied is the Offer Condition relating either to the absence of Restraints or to the receipt of required regulatory approvals) (the length of such periods to be determined by MTI) or such other number of business days as the parties may agree (subject to the right of the Purchaser to waive any Offer Condition (other than the Minimum Condition) in accordance with the Merger Agreement and the parties’ respective rights to terminate the Merger Agreement in accordance with its terms and (ii) the Purchaser shall extend the Offer for the minimum period required by applicable law or the applicable rules, regulations, interpretations or positions of the SEC or its staff or the NYSE. In addition, if on the then-scheduled Expiration Date, each of the Offer Conditions has been satisfied, or waived by MTI or us if permitted under the Merger Agreement, and the Marketing Period (as such term is defined in the Merger Agreement and described below) did not end on or prior to the immediately preceding business day, then the Purchaser shall have the right in its sole discretion to extend the Offer for one period of not more than ten business days (the length of such period to be determined by MTI), unless the Purchaser or MTI are not then in compliance in all material respects with certain financing-related obligations under the Merger Agreement. See Section 12—“The Transaction Agreements—The Merger Agreement—Financing.” The Purchaser is not required to extend the offer beyond September 11, 2014 and will not in any event extend the offer beyond September 11, 2014 without AMCOL’s prior written consent.

The Merger Agreement further provides that, subject to the terms and conditions of the Merger Agreement (including the prior satisfaction of the Minimum Condition) and satisfaction or waiver by the Purchaser of all of the Offer Conditions, after the Expiration Date, the Purchaser will, and MTI will cause the Purchaser to, promptly accept for payment and promptly thereafter pay for all Shares that are validly tendered in the Offer and not validly withdrawn (the “Offer Acceptance Time”).

Appointment of Directors after Acceptance for Payment of Shares Tendered in the Offer. The Merger Agreement provides that effective upon the Offer Acceptance Time, and at all times thereafter, subject to compliance with applicable laws and applicable rules of the NYSE, the Purchaser will be entitled to elect or designate to the AMCOL Board the number of directors, rounded up to the next whole number, equal to the product of (i) the total number of directors on the AMCOL Board (after giving effect to the directors elected or designated by the Purchaser pursuant the terms of the Agreement) and (ii) the percentage that the aggregate number of Shares beneficially owned by MTI, the Purchaser and any of their subsidiaries bears to the total number of Shares then outstanding. Upon the request of the Purchaser at any time following the Offer

Acceptance Time, AMCOL and the AMCOL Board will cause MTI’s designees to be so elected or appointed, including by increasing the number of directors, filling vacancies or newly created directorships on the AMCOL Board, and/or securing the resignations of incumbent directors. AMCOL will also cause individuals elected or designated by the Purchaser to constitute at least the same percentage (rounded up to the next whole number) as is on the AMCOL Board of each committee of the AMCOL Board. Upon the request of MTI from and after the Offer Acceptance Time, AMCOL will take all actions necessary to be treated as a “controlled company” as defined in the rules of the NYSE and make all necessary filings and disclosures. Upon the request of MTI after the Offer Acceptance Time, AMCOL will take all actions required pursuant to Section 14(f) of the Exchange Act and Rule 14f-1 thereunder in order to effect the election or designation of MTI’s designees to the AMCOL Board, including mailing the information required by Section 14(f) of the Exchange Act and Rule 14f-1 thereunder to enable the Purchaser’s designees to be elected or designated to the AMCOL Board.

In the event that the Purchaser’s designees are elected or designated to the AMCOL Board, then, until the Effective Time, AMCOL shall cause the AMCOL Board to maintain three Continuing Directors (as defined below). The term “Continuing Directors” means a member of the AMCOL Board who was a member of the AMCOL Board on or prior to the date of the Merger Agreement and who are not officers, directors or employees of MTI, the Purchaser, or any of their subsidiaries, each of whom shall be an “independent director” as defined by the NYSE rules and eligible to serve on AMCOL’s audit committee under the Exchange Act and NYSE rules, and at least one of whom shall be an “audit committee financial expert” as defined in Items 407(d)(5)(ii) and (iii) of Regulation S-K. If at any point no Continuing Directors then remain, the other directors will designate three (3) individuals to fill such vacancies who are not current or former officers, directors or employees of MTI, the Purchaser or any of their affiliates, and do not otherwise have a material financial or other interest or material relationship with MTI, the Purchaser or any of their affiliates, and such individuals will be deemed to be Continuing Directors for all purposes of the Merger Agreement. The Merger Agreement further provides that if, following the election or designation of the Purchaser’s designees to the AMCOL Board, the Purchaser’s designees constitute a majority of the AMCOL Board after the Offer Acceptance Time and prior to the Effective Time, the affirmative vote of a majority of the Continuing Directors then in office is required to (A) amend or terminate the Merger Agreement, (B) exercise or waive any of AMCOL’s rights, benefits or remedies under the Merger Agreement, if such action would adversely affect, or would reasonably be expected to adversely affect, the holders of Shares (other than MTI or the Purchaser), (C) amend AMCOL’s certificate of incorporation or bylaws, if such action would adversely affect, or would reasonably be expected to adversely affect, the holders of Shares (other than MTI or the Purchaser) or (D) take any other action of the AMCOL Board with respect to the Merger Agreement if such action would adversely affect, or would reasonably be expected to adversely affect, the holders of Shares (other than MTI or the Purchaser).

The Merger. The Merger Agreement provides that, upon the terms and subject to the conditions set forth therein, and in accordance with the DGCL, at the Effective Time, the Purchaser will be merged with and into AMCOL, and the separate corporate existence of the Purchaser will cease and AMCOL will be the Surviving Corporation. Subject to the satisfaction or waiver (to the extent permitted by applicable law) of the conditions to the Merger (and as described in this Section 12—“The Transaction Agreements—“Conditions to the Merger”) the closing of the Merger shall take place on the date of, and as promptly as practicable following, the consummation of the Offer, or such other date, time or place is agreed to in writing by MTI, the Purchaser and AMCOL (the “Closing Date”). Subject to the provisions of the Merger Agreement, on the Closing Date, MTI, the Purchaser and AMCOL will file with the Secretary of State of the State of Delaware a certificate of merger, executed in accordance with, and in such form as is required by, the relevant provisions of the DGCL with respect to the Merger (the “Certificate of Merger”). The Merger shall become effective upon the filing of the Certificate of Merger or at such later time as is agreed to by the parties hereto and specified in the Certificate of Merger (the time at which the Merger becomes effective being referred to herein as the “Effective Time”). The Merger will be governed by Section 251(h) of the DGCL. The parties agreed to take all necessary and appropriate action to cause the Merger to become effective as soon as practicable following the consummation of the Offer, without a meeting of the AMCOL stockholders in accordance with Section 251(h) of the DGCL.

Organizational Documents, Directors and Officers of the Surviving Corporation. The Merger Agreement provides that at the Effective Time, the certificate of incorporation and the bylaws of AMCOL, as in effect immediately prior to the Effective Time, will be amended to read as the certificate of incorporation and the bylaws of the Purchaser read immediately prior to the Effective Time, until thereafter amended in accordance therein or with applicable law, except (i) that references to the Purchaser will be automatically amended and will become references to the Surviving Corporation, (ii) provisions of the certificate of incorporation of the Purchaser relating to the incorporator of the Purchaser shall be omitted and (iii) changes necessary so that they will be in compliance with the provisions of the Merger Agreement relating to indemnification of directors and officers of AMCOL. Each of the parties to the Merger Agreement will take all necessary action to cause the directors of the Purchaser immediately prior to the Effective Time to be the directors of the Surviving Corporation immediately following the Effective Time, until their successors are duly elected or appointed and qualified or their earlier death, resignation or removal in accordance with the certificate of incorporation and bylaws of the Surviving Corporation. The officers of AMCOL immediately prior to the Effective Time will be the officers of the Surviving Corporation until their successors are duly appointed and qualified or their earlier death, resignation or removal in accordance with the certificate of incorporation and bylaws of the Surviving Corporation.

As of the Effective Time, all Shares shall no longer be outstanding and shall automatically be canceled and shall cease to exist, and the holders immediately prior to the Effective Time of Shares not represented by certificates and the holders of certificates that which immediately prior to the Effective Time represented Shares shall cease to have any rights with respect thereto, except the right to receive the Merger Consideration upon surrender thereof (without interest and subject to any withholding tax).

Treatment of Equity Awards. No later than the Effective Time, MTI shall provide all funds necessary to fulfill the obligations under this section to the Surviving Corporation, and all payments required under this section shall be made at, or as soon as practicable after, the Effective Time. The following treatment applies to equity-based awards made under the 2010 Long-Term Incentive Plan, the 2006 Long-Term Incentive Plan and the 1998 Long-Term Incentive Plan or any other plan, program or arrangement providing for the grant of equity-based awards (collectively, the “AMCOL Stock Plans”).

At the Effective Time, each outstanding option to purchase Shares or stock appreciation right (each, an “Option”) will be canceled in exchange for a cash payment, subject to any tax withholdings, equal to the product of (x) the total number of Shares subject to the Option multiplied by (y) the excess, if any, of the Merger Consideration over the exercise price per share of Shares under such Option. If the exercise price per share of any such Option is equal to or greater than the Merger Consideration, then the Option will be canceled without any cash payment being made in respect thereof.

At the Effective Time, each outstanding Share issued pursuant to any AMCOL Stock Plan that is subject to specified vesting criteria (each, a “Share of Restricted Stock”) will fully vest, and automatically be cancelled and converted into the right to receive cash, subject to any tax withholdings, equal to the Merger Consideration. All outstanding dividends associated with each Share of Restricted Stock, shall be paid out by AMCOL in a cash lump sum at the Effective Time.

Immediately prior to the Effective Time, each outstanding restricted stock unit with respect to Shares (each, an “RSU”) shall be converted into a vested right to receive a cash payment equal to the Merger Consideration, subject to any tax withholdings. At the Effective Time, all outstanding dividends associated with each RSU shall be paid out by AMCOL in a cash lump sum.

At the Effective Time, each outstanding phantom Share credited to the AMCOL International Corporation Stock Unit Fund pursuant to the AMCOL Nonqualified Deferred Compensation Plan (each, a “Phantom Share”) will be canceled and an amount equal to the Merger Consideration shall be allocated among the other measurement funds under the AMCOL Nonqualified Deferred Compensation Plan.

Representations and Warranties. In the Merger Agreement, AMCOL has made customary representations and warranties to MTI and the Purchaser, which are subject to the disclosure letter to the Merger Agreement and to certain disclosure in AMCOL’s SEC filings prior to the date of the Merger Agreement, including representations relating to: organization, standing and corporate power; capitalization; authority and noncontravention; governmental approvals; SEC filings and undisclosed liabilities; required filings and consents; the absence of certain changes; compliance with laws and permits; tax matters; employee benefits matters; environmental matters; intellectual property; anti-takeover provisions; property; material contracts; the opinion of financial advisors; brokers and other advisors; the lack of necessity of a shareholder vote; information supplied; certain business practices; and insurance.

Some of the representations and warranties in the Merger Agreement made by AMCOL are qualified by “materiality” or “Company Material Adverse Effect.” For purposes of the Merger Agreement, “Company Material Adverse Effect” means any change, event, occurrence, state of facts or effect that (a) individually or in the aggregate, is, or would reasonably be expected to be, materially adverse to the business, results of operations or financial condition of AMCOL and its subsidiaries taken as a whole; other than any change, event, occurrence or effect, directly or indirectly, arising out of, resulting from or relating to the following: (i) any condition, change, event, occurrence or effect in any of the industries or markets in which AMCOL or its subsidiaries operates; (ii) any enactment of, change in, or change in interpretation of, any law or GAAP or governmental policy after the date of the Merger Agreement; (iii) general economic, regulatory or political conditions (or changes therein) or conditions (or changes therein) in the financial, credit or securities markets (including changes in interest or currency exchange rates) in any country or region in which AMCOL or any of its subsidiaries conducts business; (iv) any acts of God, natural disasters, terrorism, armed hostilities, sabotage, war or any escalation or worsening of acts of terrorism, armed hostilities or war; (v) the announcement, pendency of or performance of the Transactions, including by reason of the identity of MTI or any communication by MTI regarding the plans or intentions of MTI with respect to the conduct of the business of AMCOL or any of its subsidiaries and including the impact directly relating to any of the foregoing on any relationships, contractual or otherwise, with customers, suppliers, distributors, collaboration partners, employees or regulators; (vi) the impact of any Remedial Action (described below) on AMCOL, if required by MTI; (vii) any change in the market price, or change in trading volume, of the capital stock of AMCOL (it being understood that the facts or occurrences giving rise or contributing to such failure may be deemed to constitute, or be taken into account in determining whether there has been, or would reasonably be expected to be, a Company Material Adverse Effect); (viii) any failure by AMCOL or its subsidiaries to meet internal, analysts’ or other earnings estimates or financial projections or forecasts for any period, or any changes in credit ratings and any changes in any analysts recommendations or ratings with respect to AMCOL or any of its subsidiaries (it being understood that the facts or occurrences giving rise or contributing to such failure may be deemed to constitute, or be taken into account in determining whether there has been, or would reasonably be expected to be, a Company Material Adverse Effect)

and to the extent, in each of clauses (i) through (iv), that such change, event, occurrence or effect does not affect AMCOL and its subsidiaries, taken as a whole, in a materially disproportionate manner relative to other participants in the business and industries in which AMCOL and its subsidiaries operate; or (b) would, individually or in the aggregate, reasonably be expected to prevent or materially impede, interfere with, hinder or delay the consummation by AMCOL of the Transactions.

Additionally, the Merger Agreement provides that AMCOL has represented that the AMCOL Board, at a meeting duly called and held, duly adopted resolutions unanimously (i) approving and declaring the advisability of the Merger Agreement and the Transactions, (ii) declaring that is in the best interests of AMCOL and the stockholders of AMCOL that AMCOL enter into the Merger Agreement and consummate the Transactions and that the stockholders of AMCOL accept the Offer and tender their Shares pursuant to the Offer, (iii) declaring that the terms of the Offer and Merger are fair to AMCOL and AMCOL’s stockholders and (iv) recommending that the stockholders of AMCOL accept the Offer and tender their Shares pursuant to the Offer (the “AMCOL Board Recommendation”), which resolutions, subject to the non-solicitation provisions of the Merger Agreement, have not been rescinded, modified or withdrawn in anyway.

In the Merger Agreement, MTI and the Purchaser have made customary representations and warranties to AMCOL, including representations relating to: organization, standing and corporate power; authority and noncontravention; governmental approvals; brokers and other advisors; ownership and operations of the Purchaser; its financing commitments; ownership of Shares; and disclosure.

Some of the representations and warranties in the Merger Agreement made by the Purchaser and MTI are qualified by “materiality” or “Parent Material Adverse Effect.” “Parent Material Adverse Effect” means any change, event, occurrence or effect that would, individually or in the aggregate, reasonably be expected to prevent or materially impede, interfere with, hinder or delay the consummation by MTI or the Purchaser of the Transactions.

Conduct of Business. The Merger Agreement provides that, except as contemplated or permitted by the Merger Agreement, as required by applicable law or as set forth in the disclosure letter to the Merger Agreement, during the period from the date of the Merger Agreement until the Effective Time, unless MTI otherwise consents in writing (which consent shall not be unreasonably withheld, delayed or conditioned), AMCOL shall, and shall cause its subsidiaries to, (i) conduct their respective businesses in all material respects in the ordinary course of business consistent with past practice and (ii) use reasonable best efforts to preserve intact their present lines of business, maintain their rights and franchises, preserve their assets and properties in reasonably good repair and condition and to preserve satisfactory relationships with Governmental Authorities, employees, customers and suppliers, and other persons with which AMCOL or its subsidiaries have business dealings.

In addition, between the date of the Merger Agreement and the Effective Time, except as otherwise consented to by MTI in writing (which consent will not be unreasonably withheld, conditioned or delayed, except that the restrictions in clause (i), (iii) and, with respect to alterations of compensation and benefits under, (x) below are at approval in the sole discretion of the Purchaser), as disclosed in the disclosure letter to the Merger Agreement or as otherwise required by the Merger Agreement, AMCOL and its subsidiaries are subject to customary operating covenants and restrictions, including restrictions on:

The Merger Agreement provides that from the date of the Merger Agreement until the Effective Time, MTI and its subsidiaries will not willfully and intentionally take any action that would reasonably be expected to prevent or materially impede, interfere with, hinder or delay consummation by MTI or any of its subsidiaries of the Transactions.

Rule 14d-10 Matters. The Merger Agreement provides that prior to the Offer Acceptance Time AMCOL (acting through the AMCOL Board, its compensation committee or its “independent directors” as defined by the NYSE rules) will take all such steps as may be required to cause each agreement, arrangement or understanding that has been or will be entered into by AMCOL or its subsidiaries with any of its officers, directors or employees pursuant to which compensation, severance or other benefits is paid to such officer, director or employee to be approved as an “employment compensation, severance or other employee benefit arrangement” within the meaning of Rule 14d-10(d)(1) under the Exchange Act and to otherwise satisfy the requirements of the non-exclusive safe harbor set forth in Rule 14d-10(d) under the Exchange Act.

Non-Solicitation Provisions; Change in Recommendation. The Merger Agreement provides that AMCOL and its subsidiaries and their respective officers, directors and employees shall, and shall use their reasonable best efforts to cause their other representatives, to immediately cease and cause to be terminated all existing discussions or negotiations with any person conducted prior to the date of the Merger Agreement with respect to any Takeover Proposal (defined below) or any proposal reasonably expected to lead to, any Takeover Proposal and shall promptly request the return from, or destruction by, all such persons of all copies of non-public information previously furnished or made available to such persons by or on behalf of AMCOL in accordance with the terms of any confidentiality or similar agreement in place with such person.

In addition, the Merger Agreement contains provisions pursuant to which each of AMCOL and its subsidiaries, and their respective officers, directors and employees shall not, and shall use their reasonable best efforts to cause their other representatives not to, directly or indirectly:

The Merger Agreement provides that any violation of the non-solicitation provisions of the Merger Agreement by any officer or director of AMCOL (or any other representative of AMCOL that is authorized, intentionally sanctioned or intentionally caused by AMCOL) shall be deemed a breach by AMCOL of the Merger Agreement.

In accordance with the provisions of the Merger Agreement, if at any time prior to the Offer Acceptance Time, in response to a bona fide written Takeover Proposal made after the date of the Merger Agreement which did not result from a breach of the Merger Agreement, AMCOL may, if the AMCOL Board determines in good faith (after consultation with outside counsel) that such Takeover Proposal is or could reasonably be expected to lead to a Superior Proposal (defined below), and after giving MTI written notice of such determination:

The Merger Agreement also provides that AMCOL will promptly provide notice to MTI in writing (and in any case within 48 hours of knowledge of receipt) of the receipt of such Takeover Proposal, or any request for information relating to AMCOL or any of the subsidiaries of AMCOL or for access to the business, properties, assets, books or records of AMCOL or any of its subsidiaries by any third party with respect to a Takeover Proposal. AMCOL will, in any such notice to MTI, indicate the identity of the person making such Takeover Proposal or request, and thereafter shall keep MTI reasonably informed on a reasonably current basis of all material developments affecting the status of and terms of such Takeover Proposal or request or any changes to the material terms thereof (and AMCOL shall provide MTI promptly after receipt thereof with copies of any material written materials constituting such Takeover Proposal or request or any changes to the material terms thereof) and of the status of any such discussions or negotiations. In addition, during the period from the date of the Merger Agreement through the Offer Acceptance Time, AMCOL shall enforce and not terminate, amend, modify or waive any provision of any confidentiality or “standstill” agreement to which AMCOL or any of its subsidiaries is a party, other than (should the AMCOL Board determine in good faith, following consultation with its legal counsel that failure to take such action would be inconsistent with its fiduciary duties under applicable law) a restriction in any applicable confidentiality or “standstill” agreement that would prohibit or restrict any such party from making a non-public bona fide written Takeover Proposal directly to the AMCOL Board (provided the foregoing shall not alter or affect any of AMCOL’s other obligations under the Merger Agreement).

Subject to the exceptions set forth below, the Merger Agreement prohibits the AMCOL Board from:

According to the provisions of the Merger Agreement, MTI shall be entitled to make a written request for reaffirmation of the type contemplated by clause (iv) above up to three (3) times in total and MTI shall not be entitled to make such a written request for reaffirmation if MTI has received from AMCOL a Notice of Adverse Recommendation Change (defined below) and the applicable Notice Period (defined below) with respect to such Notice of Adverse Recommendation Change has not ended.

At any time prior to the Offer Acceptance Time, the AMCOL Board may effect an AMCOL Adverse Recommendation Change (and, solely with respect to a Superior Proposal (defined below), terminate the Merger Agreement only if (i) (A) a Takeover Proposal (that did not result from a breach of the Merger Agreement) is made to AMCOL and not withdrawn and (B) if the AMCOL Board determines in good faith, after consultation with its outside legal counsel and financial advisors, that such Takeover Proposal constitutes a Superior Proposal, and, after consultation with outside legal counsel, that failure to take such action would reasonably be expected to be inconsistent with its fiduciary duties under applicable law, or (ii) (A) if, other than in connection with a Takeover Proposal, there is or arises an event, fact, circumstance, development or occurrence (an “Intervening Event”) that affects the business assets or operations of the AMCOL Board prior to the Offer Acceptance Time and (B) the AMCOL Board has concluded in good faith, following consultation with its outside legal counsel, that failure to take such action would reasonably be expected to be inconsistent with its fiduciary duties under applicable law.

The AMCOL Board shall not make an AMCOL Adverse Recommendation Change or, with respect to a Superior Proposal, terminate the Merger Agreement, unless (i) AMCOL shall have first provided MTI written notice (“Notice of Adverse Recommendation Change”) of its intent to, as applicable, (x) terminate the Merger Agreement to enter into a definitive acquisition agreement with respect to a Superior Proposal, which notice shall include the material terms and conditions of the transaction that constitutes such Superior Proposal, the identity of the party making such Superior Proposal, and copies of any proposed transaction agreements and related material documents with respect to such Superior Proposal, or (y) make an AMCOL Adverse Recommendation Change, which notice shall specify the details of an Intervening Event, if applicable, in each case of (x) and (y) at least four business days prior to its taking such action (the “Notice Period”); and (ii) AMCOL shall have, and shall have caused its legal counsel and financial advisors to, negotiate with MTI and its affiliates and representatives during the Notice Period in good faith (to the extent MTI has requested to negotiate) to make such modifications to the terms and conditions of the Merger Agreement (x) in the case of a Superior Proposal, so that the Merger Agreement results in a transaction no less favorable to the stockholders of AMCOL than such Takeover Proposal that was deemed a Superior Proposal and (y) in the case of an Intervening Event, modification of the Merger Agreement results in a transaction no less favorable to stockholders of AMCOL than the effect of the Intervening Event, in each case, as would enable MTI to proceed with the Transactions on such modified terms and, at the end of the Notice Period, after taking into account any such modified terms as may have been proposed by MTI since its receipt of such written notice, the AMCOL Board shall have again in good faith made the determination referred to in clause (i)(B) or (ii)(B), as applicable, of the preceding paragraph. In the event of any material revision or amendment (including, for the avoidance of doubt, any change in price) to the terms of a Superior Proposal, the AMCOL Board shall, in each case, make the determination referred to in clause (i)(B) or (ii)(B), as applicable, of the preceding paragraph, deliver a new Notice of Adverse Recommendation and commence a new Notice Period, and, in such case, all references to four business days in this paragraph shall be deemed to be two business days.

The Merger Agreement does not prohibit AMCOL or the AMCOL Board (or a duly authorized committee thereof) from (i) taking and disclosing to the stockholders of AMCOL a position contemplated by Rule 14e-2(a) under the Exchange Act or making a statement contemplated by Item 1012(a) of Regulation M-A or Rule 14d-9 under the Exchange Act, (ii) making any disclosure to the stockholders of AMCOL if the AMCOL Board (or a duly authorized committee thereof) determines in good faith, after consultation with its outside legal counsel, that the failure to make such disclosure would be inconsistent with applicable law, (iii) informing any person of the existence of the non-solicitation provisions contained in the Merger Agreement or (iv) making any “stop, look and listen” communication to the stockholders of AMCOL pursuant to Rule 14d-9(f) under the Exchange Act;

provided, however, that all actions taken or agreed to be taken by AMCOL or the AMCOL Board or any committee thereof shall comply with the provisions of the Merger Agreement.

As used in the Merger Agreement, a “Takeover Proposal” means any inquiry, proposal or offer from any person or “group” (as defined in Section 13(d) of the Exchange Act), other than MTI and its subsidiaries, relating to, or that is reasonably expected to lead to:

As used in the Merger Agreement, a “Superior Proposal” means any bona fide written Takeover Proposal on terms which the AMCOL Board (or a duly authorized committee thereof) determines in good faith, after consultation with AMCOL’s outside legal counsel and independent financial advisor to be (i) more favorable to the holders of the Shares from a financial point of view than the Transaction, taking into account all legal, financial, regulatory and other factors (including all the terms and conditions of such proposal and the Offer and the Merger Agreement (including any changes to the terms of the Offer and the Merger Agreement proposed by MTI in accordance with the Merger Agreement that the AMCOL Board considers relevant and (ii) reasonably capable of being completed in accordance with its terms, taking into account the financial, regulatory, legal and other aspects and terms of such proposal and the third party; provided that for purposes of the definition of Superior Proposal, the references to “15%” in the definition of Takeover Proposal, above, shall be deemed to be references to “50%.”

Reasonable Best Efforts. The Merger Agreement requires MTI, the Purchaser and AMCOL to cooperate and use their reasonable best efforts to:

For the purposes of the Merger Agreement, “Antitrust Laws” means the Sherman Act, the Clayton Act, the HSR Act, the Federal Trade Commission Act, and all applicable foreign antitrust laws and all other applicable

laws issued by a Governmental Authority that are designed or intended to prohibit, restrict or regulate actions having the purpose or effect of monopolization or restraint of trade or lessening of competition through merger or acquisition.

The Merger Agreement requires that each party (i) (A) make an appropriate filing of a Notification and Report Form pursuant to the HSR Act with respect to the Transactions as soon as practicable and in any event within ten business days after the date of the Merger Agreement (unless the parties otherwise agree to a different date), (B) supply as soon as practicable any additional information and documentary material that may be requested pursuant to the HSR Act and (C) use its reasonable best efforts to take, or cause to be taken, all other actions consistent with the Merger Agreement necessary to cause the expiration or termination of the applicable waiting periods under the HSR Act (including any extensions thereof) as soon as practicable and (ii) (A) make the appropriate filings under any Foreign Antitrust Laws as soon as practicable and no later than what is required to consummate the Transactions no later than three business days before September 11, 2014, (B) supply as soon as practical any additional information and documentary material that may be required or requested by any Governmental Authority and (C) use its reasonable best efforts to take or cause to be taken all other actions consistent with, and subject to, the Merger Agreement necessary to obtain any necessary approvals, consents, waivers, permits, authorizations or other actions or non-actions from each Governmental Authority as soon as practicable.

Pursuant to the Merger Agreement AMCOL, MTI and the Purchaser shall: (i) promptly notify the other parties to the Merger Agreement of, and if in writing, furnish the others with copies of (or, in the case of oral communications, advise the others of the contents of) any communication to such person from a Governmental Authority and permit the others to review and discuss in advance (and to consider in good faith any comments made by the others in relation to) any proposed written communication to a Governmental Authority, (ii) keep the other parties reasonably informed of any developments, meetings or discussions with any Governmental Authority in respect of any filings, investigation, or inquiry concerning the Transactions and (iii) not independently participate in any meeting or discussions with a Governmental Authority in respect of any filings, investigation or inquiry concerning the Transactions without giving the other party prior notice of such meeting or discussions and, unless prohibited by such Governmental Authority, the opportunity to attend or participate. However, each of MTI and AMCOL may designate any non-public information provided to any Governmental Authority as restricted to “Outside Antitrust Counsel” only and any such information shall not be shared with employees, officers or directors or their equivalents of the other party without approval of the party providing the non-public information.

The Merger Agreement provides that MTI and the Purchaser agree to use reasonable best efforts to take promptly any and all reasonable steps necessary to avoid, eliminate or resolve each and every impediment and obtain all clearances, consents, approvals and waivers under Antitrust Laws that may be required by any Governmental Authority, so as to enable the parties to close the Transactions as soon as practicable (and in any event no later than three business days prior to September 11, 2014); provided that nothing in the Merger Agreement shall require any party, or in the case of AMCOL, permit AMCOL to commit to and/or effect, by consent decree, hold separate orders, trust, or otherwise, to (i) the sale, license, holding separate or other disposition of assets or businesses of MTI or AMCOL or any of their respective subsidiaries, (ii) the termination, relinquishment, modification, or waiver of existing relationships, ventures, contractual rights, obligations or other arrangements of MTI or AMCOL or their respective subsidiaries or (iii) the creation of any relationships, ventures, contractual rights, obligations or other arrangements of MTI or AMCOL or their respective subsidiaries (each a “Remedial Action”), other than, after exhausting the parties’ obligations pursuant to the preceding paragraph, or with the consent of the Purchaser, Remedial Actions involving solely AMCOL and/or its subsidiaries that would not, after giving effect thereto, have a materially negative impact on AMCOL and its subsidiaries (or their respective businesses) taken as a whole; provided, however, that if MTI directs AMCOL to take any Remedial Action, such Remedial Action may, at the discretion of AMCOL, be conditioned upon consummation of the Transactions.

The Merger Agreement provides that, in the event that any litigation or other administrative or judicial action or proceeding is commenced, threatened or is foreseeable challenging any of the Transactions and such litigation, action or proceeding seeks, or would reasonably be expected to seek, to prevent, materially impede or materially delay the consummation of the Transactions, MTI and AMCOL shall, subject to the preceding paragraph, use their respective reasonable best efforts to take any and all action to avoid or resolve any such litigation, action or proceeding and each of AMCOL, MTI and the Purchaser shall cooperate with each other and use its respective reasonable best efforts to contest and resist any such litigation, action or proceeding and to have vacated, lifted, reversed or overturned any decree, judgment, injunction or other order, whether temporary, preliminary or permanent, that is in effect and that prohibits, prevents or restricts consummation of the Transactions as promptly as practicable and in any event no later than three business days prior to September 11, 2014.

Pursuant to the Merger Agreement, neither MTI nor the Purchaser shall, nor shall they permit their respective subsidiaries to, acquire or agree to acquire any assets, business, person or division thereof (through acquisition, license, joint venture, collaboration or otherwise outside the ordinary course), if such acquisition, would reasonably be expected to materially increase the risk of not obtaining any applicable clearance, consent, approval or waiver under Antitrust Laws with respect to the Transactions; it being understood that the foregoing shall not limit or affect any of AMCOL’s obligations under the Merger Agreement.

Public Announcements. The Merger Agreement provides that MTI and AMCOL shall consult with each other before issuing, and give each other the opportunity to review and comment upon, any press release or other public statements with respect to the Transactions and shall not issue any such press release or make any such public statement prior to such consultation, except as such party may reasonably conclude may be required by applicable law, court process or by obligations pursuant to any listing agreement with any national securities exchange or national securities quotation system (and then only after as much advance notice and consultation as is feasible); provided, however, that the foregoing restrictions shall not apply to any release or public statement (i) made or proposed to be made by AMCOL in connection with a Takeover Proposal, a Superior Proposal or an AMCOL Adverse Recommendation Change or any action taken pursuant thereto or (ii) in connection with any dispute between the parties regarding the Merger Agreement or the Transactions; provided, further, that the foregoing shall not limit the ability of any party to the Merger Agreement to make internal announcements to their respective employees and other stockholders that are not inconsistent in any material respects with the prior public disclosures regarding the Transactions.

Takeover Laws. Pursuant to the Merger Agreement, AMCOL and the AMCOL Board shall each (i) use its reasonable best efforts to ensure that no state takeover statute or similar statute or regulation is or becomes applicable to the Transactions and (ii) if any state takeover statute or similar statute becomes applicable to the Transactions, use its reasonable best efforts to ensure that such Transactions may be consummated as promptly as practicable on the terms contemplated by the Merger Agreement and otherwise to minimize the effect of such statute or regulation on the Transactions.

Indemnification and Insurance. The Merger Agreement provides that, from and after the Effective Time, MTI will cause the Surviving Corporation to indemnify, defend and hold harmless each current and former director and officer (and, to the extent provided in AMCOL’s organizational documents, other employee) of AMCOL and any of its subsidiaries to the same extent such individuals are indemnified as of the date of the Merger Agreement (including with respect to advancement of expenses) by AMCOL pursuant to AMCOL’s and any of its subsidiaries’ respective organizational documents and indemnification agreements, if any, in existence on the date of the Merger Agreement with such individuals for acts or omissions occurring prior to the Effective Time.

Prior to the Effective Time, MTI shall, or shall request AMCOL to, purchase and prepay a six-year “tail” policy on terms and conditions providing substantially equivalent benefits and coverage levels as the policies of directors’ and officers’ liability insurance and fiduciary liability insurance in effect as of the date of the Merger

Agreement as maintained by AMCOL and its subsidiaries with respect to matters arising on or before the Effective Time (the “D&O Insurance”), covering without limitation the Transactions (the “Tail Policy”); provided, however, that if such “tail” policy is not available at a cost per year equal to or less than 250% of the aggregate annual premiums paid by AMCOL during the most recent policy year for the D&O Insurance, MTI or, at MTI’s request, AMCOL shall purchase the best coverage as is reasonably available for such amount. MTI shall cause the Tail Policy to be maintained in full force and effect, for its full term, and cause all obligations thereunder to be honored by the Surviving Corporation.

In the event that MTI, the Surviving Corporation or any of their respective successors or assigns (i) consolidates with or merges into any other person and is not the continuing or surviving corporation or entity of such consolidation or merger or (ii) transfers or conveys all or substantially all of its properties and assets to any person, then, and in each such case, provision shall be made so that the successors and assigns of MTI and the Surviving Corporation shall assume all of the indemnification and insurance obligations set forth above.

Litigation. AMCOL will give MTI the opportunity to participate in, review and comment on all material filings or responses to be made by AMCOL in the defense or settlement of any stockholder litigation against AMCOL or any of its directors or officers relating to the Merger Agreement or the Transactions, and no such settlement of any stockholder litigation shall be agreed to without MTI’s prior written consent, such consent not to be unreasonably withheld, conditioned or delayed, except that MTI shall not be obligated to consent to any settlement which does not include full release of MTI and each of its affiliates or which imposes an injunction or other equitable relief upon MTI or any of its affiliates (including, after the Effective Time, the Surviving Corporation). AMCOL shall notify MTI promptly (and in any event within 48 hours) of the commencement of any such stockholder litigation of which it has received notice.

Section 16. Prior to the Offer Acceptance Time, AMCOL shall take all steps reasonably necessary to cause the Transactions, including any dispositions of equity securities AMCOL (including derivative securities with respect to such equity securities of AMCOL) by each individual who is or will be subject to the reporting requirements of Section 16(a) of the Exchange Act with respect to AMCOL, to be exempt under Rule 16b-3 promulgated under the Exchange Act.

Employee Matters. For a period of one year following the Effective Time, MTI shall provide, or shall cause to be provided, to each employee of AMCOL and its subsidiaries (including the Surviving Corporation and its subsidiaries) as of the Effective Time (“AMCOL Employees”), (i) annual base salary and base wages and cash incentive compensation opportunities (including target bonus amounts that are payable subject to the satisfaction of performance criteria in effect immediately prior to the Effective Time, but excluding any long-term incentive awards) that are each no less favorable than that in effect as of the Effective Time and (ii) employee benefits that are no less favorable in the aggregate than the employee benefits provided to the AMCOL Employees immediately prior to the Effective Time. Notwithstanding any other provision of the Merger Agreement to the contrary, MTI shall or shall cause the Surviving Corporation to provide AMCOL Employees whose employment terminates during the one year period following the Effective Time with severance benefits at levels no less favorable than and pursuant to the terms of MTI’s current severance policies or, if more favorable, then as required by applicable local law. Notwithstanding the foregoing, terms of continued employment of any Current Employee subject to a collective bargaining agreement shall be governed by the applicable collective bargaining agreement.

MTI shall provide customary service credit to AMCOL Employees under its benefit plans (other than accruals defined benefit plans).

MTI shall honor all obligations under the AMCOL benefit plans and compensation and severance arrangements and agreements in accordance with the terms of such plans as in effect immediately before the Effective Time. The Transactions shall be deemed to constitute a change in control under such AMCOL benefit plans, arrangements or agreements.

MTI shall cause the Surviving Corporation to pay the AMCOL Employees employed by AMCOL on December 31, 2014 such AMCOL Employees’ annual incentive bonuses, calculated in accordance with the bonus plan in effect as of the date of the Merger Agreement and consistent with past practice.

Payoff Letter. The Merger Agreement provides that no later than the fifth business day prior to the Offer Acceptance Time, AMCOL will cause the administrative agent for the lenders under the Credit Agreement, dated as of January 12, 2012, among AMCOL, certain borrowing subsidiaries and guarantors party thereto from time to time, the lenders party thereto and BMO Harris Bank N.A., as administrative agent (“Senior Credit Facility”) to prepare and deliver to AMCOL a customary “payoff letter” or similar document in form and substance reasonably satisfactory to MTI specifying the aggregate amount of AMCOL’s obligations in respect of indebtedness (including principal, interest, fees, expenses, prepayment penalties or payments and other amounts payable under the Senior Credit Facility) that will be outstanding as of the Closing Date under the Senior Credit Facility and providing, upon receipt of such amounts, (i) that all indebtedness under or pursuant to the Senior Credit Facility shall have been repaid and discharged and (ii) for the release of all claims and liens held by or on behalf of such lenders in respect of the properties and assets of AMCOL and its subsidiaries. AMCOL shall also have made arrangements reasonably satisfactory to MTI and have provided to MTI recordable form lien releases and other documents reasonably requested by MTI prior to the Closing Date such that all liens on the assets or properties of the AMCOL or any of its subsidiaries that are not permitted liens shall be (or shall have been) satisfied, terminated and discharged on or prior to the Closing Date.

Actions with Respect to 5.46% Notes. AMCOL shall prepare all notices, certificates and other documents required to be delivered to holders of AMCOL’s 5.46% Guaranteed Senior Notes due 2020 (the “5.46% Notes”) in connection with the Transactions, including the execution of the Merger Agreement, pursuant to the Note Purchase Agreement governing the 5.46% Notes (the “Note Purchase Agreement”). AMCOL shall deliver all such notices, certificates and other documents to holders of the 5.46% Notes in accordance with the terms and within the time periods specified in the Note Purchase Agreement, including, without limitation, the delivery of the notices and certificates required pursuant to Section 8.7 of the Note Purchase Agreement, and shall provide MTI the reasonable opportunity to review and comment in a timely manner on each of the foregoing notices, certificates and documents reasonably in advance of their delivery, it being understood that AMCOL’s obligation to prepay any 5.46% Notes pursuant to the offer of prepayment contained in any such notice shall not occur on or prior to the Effective Time.

No Control of Other Party’s Business. Nothing in the Merger Agreement is intended to give MTI or Purchaser, directly or indirectly, the right to control or direct AMCOL’s or its subsidiaries’ operations prior to the Effective Time. Prior to the Effective Time, AMCOL shall exercise, consistent with the terms and conditions of the Merger Agreement, complete control and supervision over its subsidiaries’ respective operations.

Financing. The Merger Agreement requires MTI to use its reasonable best efforts to take, or cause to be taken, all actions and to do, or cause to be done, all things necessary, proper or advisable to arrange and obtain debt financing in the aggregate amount set forth in the Debt Commitment Letter (the “Financing”) on the terms and conditions described in the Debt Commitment Letter, and prohibits MTI from permitting any amendment or modification to be made to, or any waiver of any provision or remedy under, the Debt Commitment Letter if such amendment, modification or waiver would (i) reduce the aggregate amount of the Financing below the amount that would be required to consummate the Transactions or (ii) impose new or additional conditions, or otherwise amend, modify or expand any conditions, to the receipt of the Financing, in the case of either clause (i) or (ii) above, in a manner that would reasonably be expected to (A) materially delay or prevent the ability of MTI to consummate the Transactions, (B) make the funding of the Financing (or satisfaction of the conditions to obtaining the Financing) materially less likely to occur or (C) adversely impact the ability of MTI or the Purchaser to enforce its rights against the other parties to the Debt Commitment Letter or the definitive agreements with respect thereto; provided, however, that MTI and the Purchaser may, without the consent of AMCOL, (1) amend the Debt Commitment Letter (A) in accordance with the “market flex” provisions thereof and (B) to add lenders, lead arrangers, bookrunners, syndication agents or similar entities who had not executed

the Debt Commitment Letter as of the date of the Merger Agreement or (2) otherwise amend or replace the Debt Commitment Letter so long as in the case of clause (2), (x) such amendment does not impose terms or conditions that would reasonably be expected to materially delay or prevent the ability of MTI to consummate the Transactions, (y) the terms are not less beneficial in any material respect to MTI or the Purchaser than those in the Debt Commitment Letter as in effect on the date of the Merger Agreement and (z) with respect to replacements, the replacement debt commitments otherwise satisfy the terms and conditions of an Alternative Financing set forth below. In the event of such amendment or replacement of the Debt Commitment Letter as permitted by the proviso to the immediately preceding sentence, the financing under such amended or replaced Debt Commitment Letter will be deemed to be “Financing” as such term is used in the Merger Agreement.

The Merger Agreement requires MTI to use its reasonable best efforts to (I) maintain in effect the Debt Commitment Letter (including any definitive agreements entered into in connection therewith), (II) satisfy on a timely basis all conditions in the Debt Commitment Letter applicable to, and within the control of, MTI and the Purchaser to obtaining the Financing at or prior to the Offer Acceptance Time, (III) negotiate as promptly as practicable and, on or prior to the Offer Acceptance Time, enter into definitive agreements with respect to the Debt Commitment Letter on terms and conditions contained in the Debt Commitment Letter or consistent in all material respects with the Debt Commitment Letter (including any applicable “market flex” provisions) or otherwise as agreed by MTI and the lenders thereunder (such definitive agreements, together with the Debt Commitment Letter, the “Financing Agreements”) and promptly upon execution thereof provide complete and executed copies of such definitive agreements to AMCOL, (IV) consummate the Financing at or prior to the Offer Acceptance Time and (V) fully enforce the counterparties’ obligations and its rights under the Financing Agreements, including by suit or other appropriate proceeding to cause the lenders under the Financing to fund in accordance with their respective commitments if all conditions to funding the Financing in the applicable Financing Agreements have been satisfied or waived. The Merger Agreement requires MTI to keep AMCOL reasonably informed on a timely basis of the status of MTI’s and the Purchaser’s efforts to arrange the Financing and to satisfy the conditions thereof, including, upon AMCOL’s request, advising and updating AMCOL, in a reasonable level of detail, with respect to status, and material terms of the material definitive documentation for the Financing. If any portion of that amount of the Financing becomes reasonably likely to be unavailable on the terms and conditions (including any “market flex” provisions) contemplated in the Debt Commitment Letter, (i) MTI will promptly notify AMCOL and (ii) MTI will use its reasonable best efforts to arrange and obtain alternative financing from alternative sources in an amount sufficient, when added to any portion of the Financing that is available and cash on hand and other readily available liquidity, to pay in cash all amounts required to be paid by MTI in cash in connection with the Transactions with terms and conditions not materially less favorable, taken as a whole (and taking into account the “market flex” provisions of the Debt Commitment Letter), to MTI, the Purchaser and AMCOL than the terms and conditions set forth in the applicable Financing Agreements (“Alternative Financing”) as promptly as practicable following the occurrence of such event. In such event, (1) the term “Financing” as used in the Merger Agreement and described herein will be deemed to include any such alternative debt financing, (2) the term “Financing” will be deemed to include the Alternative Financing, (3) the term “Debt Commitment Letter” will be deemed to include any commitment letters with respect to any such alternative debt financing and (4) the term “Financing Agreements” will be deemed to include any definitive agreement with respect to the Alternative Financing.

Prior to the Offer Acceptance Time, AMCOL is required to provide to MTI, and to cause its subsidiaries to provide, at MTI’s cost and expense, and to use reasonable best efforts to cause its representatives to provide, all cooperation reasonably requested by MTI that is customary or necessary in connection with arranging, obtaining and syndicating the Financing and causing the conditions in the Financing Agreements to be satisfied. Notwithstanding the foregoing, (i) solely MTI shall be responsible for provision of any post-closing pro forma financial information, including cost savings, synergies, capitalization, ownership or other pro forma adjustments, (ii) neither AMCOL nor any of its subsidiaries or their respective representatives shall be required to enter into any certificate, document, agreement or instrument in connection with the Financing which will be effective prior to the Offer Acceptance Time, (iii) nothing in the Merger Agreement shall require cooperation

contemplated thereby to the extent it would interfere unreasonably with the business or operations of AMCOL or

any of its subsidiaries, (iv) none of AMCOL or any of its subsidiaries will be required to pay any commitment or other similar fee or incur any other liability in connection with the Financing prior to the Offer Acceptance Time for which it is not promptly reimbursed or simultaneously indemnified, and (v) nothing in the Merger Agreement shall require cooperation or assistance from an AMCOL director, officer or employee to the extent such AMCOL director, officer or employee is reasonably likely to incur any personal financial liability by providing such cooperation or assistance that will not be repaid, reimbursed or indemnified in full by MTI. MTI is required to promptly, upon request by AMCOL, reimburse AMCOL for all reasonable out-of-pocket costs and expenses (including reasonable attorneys’ fees) incurred by AMCOL or any of its subsidiaries in connection with such cooperation of AMCOL and its subsidiaries. MTI is required to indemnify and hold harmless AMCOL, its subsidiaries and their respective representatives from and against any and all losses, damages, claims, costs or expenses suffered or incurred by any of them in connection with the arrangement of the Financing and any information used in connection therewith, except with respect to any information relating to AMCOL provided in writing by AMCOL or any of its subsidiaries or any fraud or intentional misrepresentations or willful misconduct by any such persons.

As described above, if on the then-scheduled Expiration Date, each of the Offer Conditions has been satisfied, or waived by MTI or the Purchaser if permitted under the Merger Agreement, and the Marketing Period (as such term is defined in the Merger Agreement and described below) did not end on or prior to the immediately preceding business day, then the Purchaser shall have the right in its sole discretion to extend the Offer for one period of not more than ten business days (the length of such period to be determined by MTI), unless the Purchaser or MTI are not then in compliance in all material respects with certain financing-related obligations under the Merger Agreement, which are described above.

As used in the Merger Agreement, “Marketing Period” means the first period of 15 consecutive business days after the date of the Merger Agreement throughout which MTI shall have the Required Information (as defined in the Merger Agreement and described below); provided, however, that (A) (x) the Marketing Period shall exclude July 4, 2014 (it being understood that such exclusion shall not be deemed a “business day”, including for purposes of the consecutive business day requirement) and (y) if the Marketing Period has not ended prior to August 15, 2014, such 15 business day period shall commence no earlier than September 2, 2014, (B) the Marketing Period shall end on any earlier date on which the Financing is consummated and the proceeds thereof are received by MTI and (C) the Marketing Period shall not be deemed to have commenced if, prior to the completion of such 15 business day period, (1) AMCOL’s auditor shall have withdrawn its audit opinion with respect to any year end audited financial statements set forth in the Required Information, or (2) any of the financial statements included in the Required Information shall have been restated or AMCOL or any subsidiary shall have publicly announced, or the board of directors (or similar governing body) of AMCOL or any subsidiary shall have determined, that a restatement of any such financial statements included in the Required Information is required, in which case the Marketing Period shall be deemed not to commence at the earliest unless and until such restatement has been completed or AMCOL or such subsidiary, as applicable, has determined that no restatement shall be required.

As used in the Merger Agreement, “Required Information” means (a) all customary financial and other information regarding AMCOL and its subsidiaries that is available to or readily obtainable by AMCOL as may be reasonably requested by MTI or the Purchaser, including, if applicable, financial statements prepared in accordance with GAAP, audit reports, other information and data, in each case, to allow MTI to prepare a pro forma balance sheet to give effect to the Transactions, and other information and data of the type and form, and for the periods, customarily included in offering documents used to syndicate credit facilities of the type to be included in the Financing, assuming that such syndication of credit facilities was consummated at the same time during AMCOL’s fiscal year as such syndication will be made and (b) the historical consolidated financial statements identified in paragraph (5) of Exhibit B to the Debt Commitment Letter as of the date of the Merger Agreement (or any substantially identical requirements in any amendment or replacement thereof permitted or required pursuant to the Merger Agreement).

Conditions to the Merger. The Merger Agreement provides that the respective obligations of each of MTI, the Purchaser and AMCOL to effect the Merger are subject to the satisfaction (or waiver, if permissible under applicable law) on or prior to the Effective Time of the following conditions:

Termination. The Merger Agreement may be terminated and the Transactions abandoned at any time prior to the Effective Time:

Effect of Termination. In the event of the termination of the Agreement, written notice thereof shall be given to the other party or parties, specifying the provision of the Merger Agreement pursuant to which such termination is made, and the Merger Agreement shall become null and void (other than confidentiality and certain other provisions, which shall survive such termination), and there will be no liability on the part of MTI, the Purchaser or AMCOL or their respective directors, officers and affiliates; provided, however, that, subject to the provisions below describing the Termination Fee (including the limitations on liability contained therein) no party shall be relieved or released from any liabilities or damages arising out of any willful or material breach of the Merger Agreement. The Confidentiality Agreement shall survive in accordance with its terms the termination of the Merger Agreement.

Termination Fee. The Merger Agreement contemplates that a termination fee of $39,000,000 (the “Termination Fee”) will be payable by AMCOL to MTI under any of the following circumstances:

Pursuant to the Merger Agreement, in no event will AMCOL be required to pay the Termination Fee on more than one occasion. Notwithstanding anything to the contrary in the Merger Agreement, except with respect to a material and willful breach of the non-solicitation obligations of AMCOL (and not its representatives) under the Merger Agreement in which case any further liability shall be limited to the amount of MTI’s or the Purchaser’s or their respective subsidiaries’ costs and expenses arising out of or relating to the Transactions, including, but not limited to, those incurred in connection with enforcing MTI’s or the Purchaser’s or their respective subsidiaries’ rights under the Merger Agreement, payment of fees to any of their representatives as relates to the Transactions and any financing arrangements or activities related to the Transactions, the parties agreed that the payment of the Termination Fee is the sole and exclusive remedy available to MTI and the Purchaser with respect to the Merger Agreement and the Transactions in the event any such payment becomes due and payable, and, upon payment of the Termination Fee, AMCOL (and AMCOL’s affiliates and its and their respective directors, officers, employees, stockholders and representatives) shall have no further liability to MTI and the Purchaser under the Merger Agreement.

AMCOL and MTI entered into a confidentiality letter agreement, dated as of November 6, 2013 (the “Confidentiality Agreement”), pursuant to which AMCOL and MTI agreed that, subject to certain limitations, certain information related to the other party (the “Disclosing Party”) or its affiliates furnished to such party (the “Receiving Party”) or its affiliates and its and their respective representatives, shall be used by the Receiving Party and its representatives solely for the purpose of evaluating, negotiating and executing a possible negotiated transaction between or involving MTI and AMCOL and would, for a period of two years from the date of the Confidentiality Agreement, be kept confidential, except as provided in the Confidentiality Agreement. MTI also agreed, among other things, to certain “standstill” provisions which prohibit MTI and its representatives from taking certain actions with respect to AMCOL for a period ending on the six-month anniversary of the date of the Confidentiality Agreement. In addition, AMCOL and MTI agreed, subject to certain exceptions, that certain information, including information that related to MTI and AMCOL and the existence of a possible transaction involving MTI and AMCOL, shall be kept confidential.

The foregoing summary description of the Confidentiality Agreement is qualified in its entirety by reference to the Confidentiality Agreement, a copy of which is attached as an exhibit to the Schedule TO.

AMCOL and MTI entered into an exclusivity agreement, dated as of January 14, 2014 (the “Exclusivity Agreement”), pursuant to which AMCOL agreed that, during the period after January 14, 2014 and prior to January 31, 2014 (the “Interim Period”), AMCOL would not, and AMCOL would cause its affiliates and its and their respective representatives not to, provide to any third party a draft merger agreement or other definitive documentation with respect to any alternative transaction or a response to a draft merger agreement or other definitive documentation with respect to any alternative transaction, or enter into or consummate the transactions contemplated by any such agreement or documentation. At any time during the Interim Period, either party was permitted to terminate the Exclusivity Agreement by providing two business days’ prior written notice to the other party. If not terminated earlier pursuant to the terms thereof, the Exclusivity Agreement would have terminated upon the earlier of (1) February 15, 2014 and (2) execution of a definitive agreement between AMCOL and MTI relating to a potential transaction. On January 31, 2014, a representative of Kirkland & Ellis sent AMCOL’s notice of termination of the Exclusivity Agreement to a representative of Cravath. If the Exclusivity Agreement had not been terminated prior to the end of the Interim Period, immediately following the end of the Interim Period AMCOL would have been required to terminate any discussions or negotiations with third parties regarding an alternative transaction and AMCOL would have been subject to certain other restrictions for the remaining term of the Exclusivity Agreement described above.

The foregoing summary of the provisions of the Exclusivity Agreement is qualified in its entirety by reference to the Exclusivity Agreement, a copy of which is filed as an exhibit to the Schedule 14D-9 and is incorporated herein by reference.

Purpose of the Offer. The purpose of the Offer and the Merger is for MTI, through the Purchaser, to acquire control of, and the entire equity interest in, AMCOL, while allowing AMCOL’s stockholders an opportunity to receive the Offer Price promptly by tendering their Shares pursuant to the Offer. Pursuant to the Merger, MTI will acquire all outstanding Shares not tendered and purchased pursuant to the Offer or otherwise. If the Offer is successful, the Purchaser intends to consummate the Merger as promptly as practicable. After completion of the Offer and the Merger, AMCOL will be a wholly owned subsidiary of MTI.

Stockholders of AMCOL who tender their Shares pursuant to the Offer will cease to have any equity interest in AMCOL or any right to participate in its earnings and future growth after the Offer Closing. If the Merger is consummated, non-tendering stockholders also will no longer have an equity interest in AMCOL. On the other

hand, after tendering their Shares pursuant to the Offer or the subsequent Merger, stockholders of AMCOL will not bear the risk of any decrease in the value of Shares.

No Stockholder Approval. If the Offer is consummated, we do not anticipate seeking the approval of AMCOL’s remaining public stockholders before effecting the Merger. Section 251(h) of the DGCL provides that, subject to certain statutory requirements, if following consummation of a successful tender offer for a public corporation, the acquirer holds at least the amount of shares of each class of stock of the target corporation that would otherwise be required to approve a merger involving the target corporation, and the other stockholders receive the same consideration for their stock in the merger as was payable in the tender offer, the acquirer can effect a merger without the action of the other stockholders of the target corporation. Therefore, the parties have agreed that, subject to the conditions specified in the Merger Agreement, the Merger will become effective as soon as practicable after the consummation of the Offer, without a stockholder vote to adopt the Merger Agreement or any other action by the stockholders of AMCOL, in accordance with Section 251(h) of the DGCL.

Plans for AMCOL. Assuming the Purchaser purchases a majority of the outstanding Shares (on a fully diluted basis) pursuant to the Offer, MTI is entitled to, and if the Merger is not effected pursuant to Section 251(h) of the DGCL promptly following the consummation of the Offer, currently intends to, exercise its rights under the Merger Agreement to obtain pro rata representation on, and control of, the AMCOL Board. At the Effective Time, the Certificate of Incorporation and the Bylaws of the Surviving Corporation will be amended to read as the Certificate of Incorporation and the Bylaws of the Purchaser read immediately prior to the Effective Time until thereafter changed or amended in accordance with applicable law, except (i) that references to the Purchaser will be automatically amended and will become references to the Surviving Corporation, (ii) provisions of the certificate of incorporation of the Purchaser relating to the incorporator of the Purchaser shall be omitted and (iii) changes necessary so that they will be in compliance with the provisions of the Merger Agreement relating to indemnification of directors and officers of AMCOL. The Purchaser’s directors and officers immediately prior to the Effective Time will be the initial directors and officers of the Surviving Corporation until their successors have been elected or appointed. See “Section 12—The Transaction Agreements—Organizational Documents, Directors and Officers of the Surviving Corporation” above.

MTI and the Purchaser are conducting a detailed review of AMCOL and its assets, corporate structure, capitalization, operations, properties, policies, management and personnel, and will consider what changes would be desirable in light of the circumstances that exist upon completion of the Offer. MTI and the Purchaser will continue to evaluate the business and operations of AMCOL during the pendency of the Offer and after the consummation of the Offer and the Merger and will take such actions as they deem appropriate under the circumstances then existing. Thereafter, MTI intends to review such information as part of a comprehensive review of AMCOL’s business, operations, capitalization and management with a view to optimizing development of AMCOL’s potential in conjunction with AMCOL’s or MTI’s existing businesses. Possible changes could include changes in AMCOL’s business, corporate structure, charter, bylaws, capitalization, board of directors and management. Plans may change based on further analysis and MTI, the Purchaser and, after completion of the Offer and the Merger, the reconstituted AMCOL Board, reserve the right to change their plans and intentions at any time, as deemed appropriate.

Except as disclosed in this Offer to Purchase, MTI and the Purchaser do not have any present plan or proposal that would result in the acquisition by any person of additional securities of AMCOL, the disposition of securities of AMCOL, an extraordinary corporate transaction, such as a merger, reorganization or liquidation, involving AMCOL or its subsidiaries or the sale or transfer of a material amount of assets of AMCOL or its subsidiaries.

The Merger Agreement provides that between the date of the Merger Agreement and the Effective Time, except as otherwise consented to by MTI in writing (which consent will not be unreasonably withheld, delayed or

conditioned), AMCOL will not, and will not permit any of its subsidiaries to, declare, authorize, set aside for payment or pay any dividend on, or make any other distribution (whether in cash, stock or property) in respect of, any Shares or other equity interests, other than dividends and distributions paid by any subsidiary of AMCOL to AMCOL or any wholly owned subsidiary of AMCOL other than quarterly cash dividends not to exceed $.20 per Share and with declaration, record and payment dates at times consistent with historical practice over the prior two fiscal years, and, if a record date has not been set (in reference to a date consistent with such historical practice) prior to the Effective Time, no dividend shall be paid.

Capitalized terms used but not defined in this Section 15—“Conditions of the Offer” have the meanings ascribed to them in the Merger Agreement.

Notwithstanding any other terms or provisions of the Offer or the Merger Agreement, Purchaser will not be obligated to accept for payment, and, subject to the rules and regulations of the SEC (including Rule 14e-l(c) promulgated under the Exchange Act), will not be obligated to pay for, or may delay the acceptance for payment of or payment for, any validly tendered Shares pursuant to the Offer (and not theretofore accepted for payment or paid for), if immediately prior to the Expiration Date, there shall not have been validly tendered (not including as tendered those Shares that are tendered pursuant to guaranteed delivery procedures and not actually delivered prior to the Expiration Date) and not validly withdrawn that number of Shares that when added to the Shares then owned by Purchaser would represent one Share more than one-half (1/2) of the sum of: (i) all Shares then outstanding, and (ii) all Shares that AMCOL may be required to issue upon the vesting (including vesting solely as a result of the consummation of the Offer), conversion, settlement or exercise of all then outstanding warrants, options, obligations or securities convertible or exchangeable into Shares, or other rights to acquire or be issued Shares (including all then outstanding Options, Shares of Restricted Stock and Company RSUs), regardless of the conversion or exercise price or other terms and conditions thereof) (the condition described in this paragraph the “Minimum Condition”).

Notwithstanding any other term or provision of the Offer or the Merger Agreement, Purchaser will not be obligated to accept for payment, and, subject to the rules and regulations of the SEC (including Rule 14e-l(c) promulgated under the Exchange Act), will not be obligated to pay for, or may delay the acceptance for payment of or payment for, any validly tendered Shares pursuant to the Offer (and not theretofore accepted for payment or paid for), if at the Expiration Date any of the following conditions shall not be satisfied or have been waived by the Purchaser:

The Merger Agreement provides that the foregoing conditions are in addition to, and not a limitation of, the rights of MTI and the Purchaser to extend, terminate and/or modify the Offer pursuant to the terms of the Merger Agreement.

The Merger Agreement further provides that the foregoing conditions are for the sole benefit of MTI and Purchaser, may be asserted by MTI or the Purchaser regardless of the circumstances (including any action or inaction by MTI or Purchaser, provided, that nothing in the Merger Agreement shall relieve any party to the Merger Agreement from any obligation or liability such party has under the Merger Agreement) giving rise to any such conditions and may be waived by MTI or the Purchaser in whole or in part at any time and from time to time in their sole discretion (except for the Minimum Condition), in each case, subject to the terms of the Merger Agreement and the applicable rules and regulations of the SEC. Any reference in this Section 15—“Conditions of the Offer” or in the Merger Agreement to a condition or requirement being satisfied shall be deemed to be satisfied if such condition or requirement is so waived. The failure by MTI or the Purchaser at any time to exercise any of the foregoing rights will not be deemed a waiver of any such right and each such right will be deemed an ongoing right which may be asserted at any time and from time to time.

Legal Proceedings. On February 18, 2014, a suit captioned Coyne v. AMCOL International Corporation, et al., Case No. 2014-CH-02849 was filed in the Circuit Court of Cook County, Illinois, County Department, Chancery Division. The suit is a purported class action brought on behalf of the stockholders of AMCOL. The complaint alleges that AMCOL and its directors breached fiduciary duties in connection with the then-proposed Imerys transaction which plaintiff alleges does not appropriately value AMCOL, was the result of an inadequate process and includes preclusive deal protection devices. The complaint also claims that Imerys and a wholly owned subsidiary of Imerys aided and abetted those alleged breaches of fiduciary duty. The complaint purports to seek unspecified damages and injunctive relief. On March 4, 2014, AMCOL filed a motion to dismiss the complaint.

On February 21, 2014, a suit captioned Halberstam v. AMCOL International Corporation, et al., C.A. No. 9381-VCL was filed in the Delaware Court of Chancery. The suit is a purported class action brought on behalf of the stockholders of AMCOL. The complaint alleges that AMCOL’s directors breached fiduciary duties in connection with the then-proposed Imerys transaction which plaintiff alleges does not appropriately value AMCOL, was the product of an inadequate process and includes preclusive deal protection devices. The complaint also claims that AMCOL, Imerys and a wholly owned subsidiary of Imerys aided and abetted those alleged breaches of fiduciary duty. The complaint purports to seek unspecified damages, injunctive relief, and, in the event the then-proposed Imerys transaction is consummated, rescission of the proposed transaction or rescissory damages. On February 28, 2014, Imerys and a wholly owned subsidiary of Imerys answered the complaint.

On February 24, 2014, a suit captioned City of Monroe Employees’ Retirement System v. AMCOL International Corporation, et al., Case No. 2014-CH-3236 was filed in the Circuit Court of Cook County, Illinois, County Department, Chancery Division. The suit is a purported class action brought on behalf of the stockholders of AMCOL. The complaint alleges that AMCOL’s directors breached fiduciary duties in connection with the then-proposed Imerys transaction which plaintiff alleges does not appropriately value AMCOL, was the result of an inadequate process and includes preclusive deal protection devices. The complaint also claims that AMCOL, Imerys and a wholly owned subsidiary of Imerys aided and abetted those alleged breaches of fiduciary duty. The complaint purports to seek declaratory relief, injunctive relief and, in the event that the then-proposed Imerys transaction is consummated, rescission of the then-proposed Imerys transaction. On February 27, 2014, the plaintiff filed a motion for expedited discovery and a brief in support of that motion. On March 4, 2014, AMCOL filed a motion to dismiss the complaint.

On March 4, 2014, a suit captioned Guidone v. AMCOL International Corporation, et al., Case No. 2014-CH-03751 was filed in the Circuit Court of Cook County, Illinois, County Department, Chancery Division. The suit is a purported class action brought on behalf of the stockholders of AMCOL. The complaint alleges that AMCOL’s directors breached fiduciary duties in connection with the then-proposed Imerys transaction which plaintiff alleges does not appropriately value AMCOL, was the result of an inadequate process and includes preclusive deal protection devices. The complaint also claims that AMCOL, Imerys and a wholly owned subsidiary of Imerys aided and abetted those alleged breaches of fiduciary duty. The complaint purports to seek declaratory relief, injunctive relief and, in the event that the then-proposed Imerys transaction is consummated, rescission of the then-proposed Imerys transaction or rescissory damages.

MTI, the Purchaser and AMCOL believe the claims are without merit. AMCOL intends to defend against them vigorously.

General. Except as otherwise set forth in this Offer to Purchase, based on MTI’s and the Purchaser’s review of publicly available filings by AMCOL with the SEC and other information regarding AMCOL, MTI and the Purchaser are not aware of any licenses or other regulatory permits that appear to be material to the business of AMCOL and that might be adversely affected by the acquisition of Shares by the Purchaser or MTI pursuant to the Offer or of any approval or other action by any governmental, administrative or regulatory agency or authority that would be required for the acquisition or ownership of Shares by the Purchaser or MTI pursuant to the Offer. In addition, except as set forth below, MTI and the Purchaser are not aware of any filings, approvals or other actions by or with any Governmental Authority or administrative or regulatory agency that would be required for MTI’s and the Purchaser’s acquisition or ownership of the Shares. Should any such approval or other action be required, MTI and the Purchaser currently expect that such approval or action, except as described below under “State Takeover Laws,” would be sought or taken. There can be no assurance that any such approval or action, if needed, would be obtained or, if obtained, that it will be obtained without substantial conditions; and there can be no assurance that, in the event that such approvals were not obtained or such other actions were not taken, adverse consequences might not result to AMCOL’s or MTI’s business or that certain parts of AMCOL’s or MTI’s business might not have to be disposed of or held separate. In such an event, we may not be required to purchase any Shares in the Offer. See Section 15—“Conditions of the Offer.”

Antitrust. AMCOL and MTI are both active in and outside the United States where merger regulations may require that transactions involving parties that meet or exceed certain global and local sales or assets thresholds must be notified for review under antitrust law.

Under the HSR Act, and the rules and regulations promulgated thereunder by the U.S. Federal Trade Commission (the “FTC”), certain acquisition transactions may not be consummated until certain information and documentary material has been furnished for review by the FTC and the Antitrust Division of the U.S. Department of Justice (the “Antitrust Division”) and certain waiting period requirements have been satisfied. These requirements apply to MTI by virtue of the Purchaser’s acquisition of Shares in the Offer (and the Merger).

Under the HSR Act, the purchase of Shares in the Offer may not be completed until the expiration of a fifteen-calendar-day waiting period following the filing of certain required information and documentary material concerning the Offer (and the Merger) with the FTC and the Antitrust Division, unless the waiting period is earlier terminated by the FTC and the Antitrust Division. The parties are preparing and will promptly file such Premerger Notification and Report Forms under the HSR Act with the FTC and the Antitrust Division in connection with the purchase of Shares in the Offer. Under the HSR Act, the required waiting period will expire at 11:59 pm, New York City time on the fifteenth calendar day after the filing by MTI, unless earlier terminated by the FTC and the Antitrust Division or MTI receives a request for additional information or documentary material (“Second Request”) from either the FTC or the Antitrust Division prior to that time. If a Second Request is issued, the waiting period with respect to the Offer (and the Merger) would be extended for an additional period of ten calendar days following the date of MTI’s substantial compliance with that request. If either the 15-day or 10-day waiting period expires on a Saturday, Sunday or federal holiday, then the period is extended until 11:59 p.m. of the next day that is not a Saturday, Sunday or federal holiday. The FTC or the Antitrust Division may terminate the additional ten-day waiting period before its expiration. Although AMCOL is also required to file certain information and documentary material with the FTC and the Antitrust Division in connection with the Offer, neither AMCOL’s failure to make its filing nor comply with its own Second Request in a timely manner will extend the waiting period with respect to the purchase of Shares in the Offer (and the Merger).

The FTC and the Antitrust Division frequently scrutinize the legality under the U.S. antitrust laws of transactions, such as the Purchaser’s acquisition of the Shares in the Offer and the Merger. At any time before or after the Purchaser’s purchase of Shares in the Offer and the Merger, the FTC or the Antitrust Division could take any action under the antitrust laws that it either considers necessary or desirable in the public interest, including seeking a court order (i) to enjoin the purchase of Shares in the Offer and the Merger, (ii) to require the divestiture of Shares purchased in the Offer and Merger or (iii) to require the divestiture of substantial assets of MTI, AMCOL or any of their respective subsidiaries or affiliates. Private parties, as well as state attorneys general, also may bring legal actions under the antitrust laws under certain circumstances. See Section 15—“Conditions of the Offer.”

Each of AMCOL and MTI intend to promptly file a Premerger Notification and Report Form with the FTC and the Antitrust Division in connection with the Offer.

Based on a review of the information currently available relating to the countries and businesses in which MTI and AMCOL are engaged, MTI and the Purchaser believe that mandatory antitrust merger control notification filings should also be made in Germany, Poland and Turkey with the respective national antitrust authorities of these countries (the Federal Cartel Office (the “FCO”) in Germany, the Office of Competition and Consumer Protection (the “OCCP”) in Poland and Competition Authority (the “CA”) in Turkey). Authorizations by the relevant merger control authorities in Germany, Poland and Turkey are conditions to the Offer in the Merger Agreement.

All notifications are required to be submitted pre-closing of the Merger. MTI and the Purchaser intend to submit its applications on the proposed acquisition of AMCOL and the Merger to the FCO, the OCCP and the CA as promptly as reasonably practicable after the date hereof.

Under German law, the FCO has one month to review the application from the date of a complete notification. The FCO may take an additional three months to further investigate the merits of the acquisition.

Under Polish law, the OCCP has two months to review the application from the date of a complete notification.

Under Turkish law, the CA has 15 days to conduct a preliminary review upon expiry of which the CA can request additional information or alternatively ask for suspension of the notified transaction so as to allow for an investigation of the merits of the transaction for an additional period of six months, which may be extended only once for a further six months. In the event the CA is silent throughout the preliminary review period or after submission of the additional information, the notified transaction may be consummated upon expiry of 30 days from the date of the initial or additional submission, as the case may be.

In any case, the relevant merger control authorities may give their authorization before the end of the waiting periods as described above.

MTI and the Purchaser cannot be certain that a challenge to the Offer and the Merger on antitrust grounds will not be made, or, if such challenge is made, what the result will be.

No Stockholder Approval. AMCOL has represented in the Merger Agreement that the execution, delivery and performance of the Merger Agreement by AMCOL and the consummation by AMCOL of the Offer and the Merger have been duly and validly authorized by all necessary corporate action on the part of AMCOL, and no other corporate proceedings on the part of AMCOL are necessary to authorize the Merger Agreement or to consummate the Offer and the Merger (other than the filing and recordation of appropriate merger documents as required by the DGCL). If the Offer is consummated, we do not anticipate seeking the approval of AMCOL’s remaining public stockholders before effecting the Merger. Section 251(h) of the DGCL provides that, subject to certain statutory requirements, if following consummation of a successful tender offer for a public corporation, the acquiror holds at least the amount of shares of each class of stock of the target corporation that would otherwise be required to approve a merger involving the target corporation, and the other stockholders receive the same consideration for their stock in the merger as was payable in the tender offer, the acquiror can effect a merger without any action of the other stockholders of the target corporation. Therefore, AMCOL, MTI and the Purchaser have agreed that, subject to the conditions specified in the Merger Agreement, the Merger will become effective as soon as practicable after the consummation of the Offer, without a meeting of the stockholders of AMCOL to adopt the Merger Agreement, in accordance with Section 251(h) of the DGCL.

State Takeover Laws. A number of states have adopted takeover laws and regulations that purport, to varying degrees, to be applicable to attempts to acquire securities of corporations that are incorporated in such states or that have substantial assets, stockholders, principal executive offices or principal places of business therein.

As a Delaware corporation, AMCOL has not opted out of Section 203 of the DGCL. In general, Section 203 of the DGCL prevents an “interested stockholder” (including a person who owns or has the right to acquire 15% or more of a corporation’s outstanding voting stock) from engaging in a “business combination” (defined to include mergers and certain other actions) with a Delaware corporation for a period of three years following the date such person became an interested stockholder unless, among other things, the “business combination” is approved by the board of directors of such corporation prior to such date.

AMCOL has represented to us in the Merger Agreement that the AMCOL Board (at a meeting or meetings duly called and held) has approved, for purposes of the DGCL and any other “interested stockholder” or other

similar statute or regulation that might be deemed applicable, the Offer, the Merger, the Merger Agreement and the transactions contemplated thereby. The Purchaser has not attempted to comply with any other state takeover statutes in connection with the Offer or the Merger. The Purchaser reserves the right to challenge the validity or applicability of any state law allegedly applicable to the Offer, the Merger, the Merger Agreement or the transactions contemplated thereby, and nothing in this Offer to Purchase or any action taken in connection herewith is intended as a waiver of that right. In the event that it is asserted that one or more takeover statutes apply to the Offer or the Merger, and it is not determined by an appropriate court that such statute or statutes do not apply or are invalid as applied to the Offer, the Merger, the Merger Agreement and the other agreements and transactions referred to therein, as applicable, the Purchaser may be required to file certain documents with, or receive approvals from, the relevant state authorities, and the Purchaser might be unable to accept for payment or purchase Shares tendered pursuant to the Offer or be delayed in continuing or consummating the Offer. In such case, the Purchaser may not be obligated to accept for purchase, or pay for, any Shares tendered. See Section 15—“Conditions of the Offer.”

Appraisal Rights. No appraisal rights are available to the holders of Shares in connection with the Offer. However, if the Merger takes place pursuant to Section 251(h) of the DGCL stockholders who have not tendered their Shares pursuant to the Offer and who comply with the applicable legal requirements will have appraisal rights under Section 262 of the DGCL. If you choose to exercise your appraisal rights in connection with the Merger and you comply with the applicable legal requirements under the DGCL, you will be entitled to payment for your Shares based on a judicial determination of the fair value of your Shares, together with interest, as determined by the Delaware Court of Chancery. This value may be the same, more or less than the price that the Purchaser is offering to pay you in the Offer and the Merger. Moreover, the Purchaser may argue in an appraisal proceeding that, for purposes of such a proceeding, the fair value of such Shares is less than the price paid in the Offer and the Merger.

Under Section 262 of the DGCL, where a merger is approved under Section 251(h) of the DGCL, either a constituent corporation before the effective date of the merger, or the surviving corporation within ten days thereafter, shall notify each of the holders of any class or series of stock of such constituent corporation who are entitled to appraisal rights of the approval of the merger and that appraisal rights are available for any or all shares of such class or series of stock of such constituent corporation, and shall include in such notice a copy of Section 262. The Schedule 14D-9 constitutes the formal notice of appraisal rights under Section 262 of the DGCL. Any holder of Shares who wishes to exercise such appraisal rights or who wishes to preserve his, her or its right to do so, should review the discussion of appraisal rights in the Schedule 14D-9 as well as Section 262 of the DGCL, attached as Annex C to the Schedule 14D-9, carefully because failure to timely and properly comply with the procedures specified may result in the loss of appraisal rights under the DGCL.

Any stockholder wishing to exercise appraisal rights is urged to consult legal counsel before attempting to exercise such rights.

As described more fully in the Schedule 14D-9, if a stockholder elects to exercise appraisal rights under Section 262 of the DGCL with respect to Shares held immediately prior to the Effective Time, such stockholder must do all of the following:

The foregoing summary of the rights of AMCOL’s stockholders to seek appraisal rights under Delaware law is qualified in its entirety by reference to Section 262 of the DGCL. The preservation and proper exercise of appraisal rights requires strict adherence to the applicable provisions of the DGCL. Failure to fully and precisely follow the steps required by Section 262 of the DGCL for the perfection of appraisal rights may result in the loss of those rights. A copy of Section 262 of the DGCL is included as Annex C to the Schedule 14D-9.

Appraisal rights cannot be exercised at this time. The information provided above is for informational purposes only with respect to your alternatives if the Merger is completed. If you tender your shares in the Offer, you will not be entitled to exercise appraisal rights with respect to your shares but, instead, upon the terms and subject to the conditions to the Offer, you will receive the Offer Price for your Shares.

“Going Private” Transactions. Rule 13e-3 under the Exchange Act is applicable to certain “going private” transactions and may under certain circumstances be applicable to the Merger. However, Rule 13e-3 will be inapplicable if (i) Shares are deregistered under the Exchange Act prior to the Merger or another business combination or (ii) the Merger or other business combination is consummated within one year after the purchase of Shares pursuant to the Offer and the amount paid per Share in the Merger or other business combination is at least equal to the amount paid per Share in the Offer. Neither MTI nor the Purchaser believes that Rule 13e-3 will be applicable to the Merger.

MTI and the Purchaser have retained Innisfree M&A Incorporated to be the Information Agent, Lazard Frères & Co. LLC to be the Dealer Manager and American Stock Transfer & Trust Company, LLC to be the Depositary for the Offer. The Information Agent may contact holders of Shares by mail, telephone, telecopy, telegraph and personal interview and may request banks, brokers, dealers and other nominees to forward materials relating to the Offer to beneficial owners of Shares.

The Information Agent, the Dealer Manager and the Depositary each will receive reasonable and customary compensation for their respective services in connection with the Offer, will be reimbursed for reasonable out-of-pocket expenses and will be indemnified against certain liabilities and expenses in connection therewith, including certain liabilities under federal securities laws.

Neither MTI nor the Purchaser will pay any fees or commissions to any broker or dealer or to any other person (other than to the Depositary, the Dealer Manager and the Information Agent) in connection with the solicitation of tenders of Shares pursuant to the Offer. Banks, brokers, dealers and other nominees will, upon request, be reimbursed by the Purchaser for customary mailing and handling expenses incurred by them in forwarding offering materials to their customers.

The Purchaser is not aware of any jurisdiction where the making of the Offer is prohibited by any administrative or judicial action pursuant to any valid state statute. If the Purchaser becomes aware of any valid state statute prohibiting the making of the Offer or the acceptance of the Shares, the Purchaser will make a good faith effort to comply with that state statute. If, after a good faith effort, the Purchaser cannot comply with the state statute, the Purchaser will not make the Offer to, nor will the Purchaser accept tenders from or on behalf of, the holders of Shares in that state. In those jurisdictions where applicable laws require the Offer to be made by a licensed broker or dealer, the Offer will be deemed to be made on behalf of the Purchaser by one or more registered brokers or dealers licensed under the laws of such jurisdiction to be designated by the Purchaser.

MTI and the Purchaser have filed with the SEC the Schedule TO (including exhibits) in accordance with the Exchange Act, furnishing certain additional information with respect to the Offer, and may file amendments

thereto. The Schedule TO and any amendments thereto, including exhibits, may be examined and copies may be obtained from the SEC in the manner set forth in Section 9—“Certain Information Concerning MTI and the Purchaser—Available Information.”

The Offer does not constitute a solicitation of proxies for any meeting of AMCOL’s stockholders. Any solicitation that the Purchaser or any of its affiliates might seek would be made only pursuant to separate proxy materials complying with the requirements of Section 14(a) of the Exchange Act.

Neither delivery of this Offer to Purchase nor any purchase pursuant to the Offer will, under any circumstances, create any implication that there has been no change in the affairs of MTI, the Purchaser, AMCOL or any of their respective subsidiaries since the date as of which information is furnished or the date of this Offer to Purchase.

No person has been authorized to give any information or to make any representation on behalf of MTI or the Purchaser not contained herein or in the Letter of Transmittal, and, if given or made, such information or representation must not be relied upon as having been authorized. No broker, dealer, bank, trust company, fiduciary or other person will be deemed to be the agent of the Purchaser, the Depositary, the Dealer Manager or the Information Agent for the purpose of the Offer.

The name, country of citizenship, business address, present principal occupation or employment and material occupations, positions, offices or employment for the past five years of each of the directors and executive officers of MTI and the Purchaser and certain other information are set forth below. The business address of each director and executive officer of MTI is c/o Minerals Technologies Inc., 622 Third Avenue, New York, New York 10017-6707, and the current phone number is (212) 878-1800. The business address of each director and executive officer of the Purchaser is c/o Minerals Technologies Inc., 622 Third Avenue, New York, New York 10017-6707, and the current phone number is (212) 878-1800.

The Letter of Transmittal and certificates evidencing Shares and any other required documents should be sent or delivered by each stockholder or its, his or her broker, dealer, commercial bank, trust company or other nominee to the Depositary at its address set forth below:

Questions or requests for assistance may be directed to the Information Agent or the Dealer Manager at their respective telephone numbers and addresses set forth below. Additional copies of this Offer to Purchase, the Letter of Transmittal and the Notice of Guaranteed Delivery may also be obtained from the Information Agent. Stockholders may also contact their broker, dealer, commercial bank or trust company for assistance concerning the Offer.


SUMMARY TERM SHEET			3
INTRODUCTION			12
THE TENDER OFFER			14
1. Terms of the Offer.			14
2. Acceptance for Payment and Payment for Shares.			16
3. Procedures for Accepting the Offer and Tendering Shares.			16
4. Withdrawal Rights.			20
5. Certain United States Federal Income Tax Consequences.			20
6. Price Range of Shares; Dividends.			22
7. NYSE Listing; Exchange Act Registration; Margin Regulations.			23
8. Certain Information Concerning AMCOL.			24
9. Certain Information Concerning MTI and the Purchaser.			25
10. Source and Amount of Funds.			27
11. Background of the Offer; Past Contacts or Negotiations with AMCOL.			29
12. The Transaction Agreements.			35
13. Purpose of the Offer; No Stockholder Approval; Plans for AMCOL.			54
14. Dividends and Distributions.			55
15. Conditions of the Offer.			56
16. Certain Legal Matters; Regulatory Approvals.			57
17. Fees and Expenses.			62
18. Miscellaneous.			62
SCHEDULE I			I-1


	Stock Price				Cash Dividends Declared Per Share
	High		Low		Cash Dividends Declared Per Share
Year Ended December 31, 2012
First Quarter	$	30.96	$	25.93	$	.18
Second Quarter		34.27		26.63		.18
Third Quarter		36.23		27.70		.20
Fourth Quarter		34.68		28.26		.20

Year Ending December 31, 2013
First Quarter	$	33.89	$	28.68	$	.20
Second Quarter		32.92		27.59		.20
Third Quarter		37.05		31.61		.20
Fourth Quarter		34.51		29.48		.20

Year Ending December 31, 2014
First Quarter (through March 20, 2014)	$	47.26	$	33.40	$	.20


Name, Country of Citizenship, Position		Present Principal Occupation or Employment; Material Positions Held During the Past Five Years; Certain Other Information
John J. Carmola United States Director of MTI		Mr. Carmola, Retired Former Segment President at Goodrich Corporation. He currently is a Consultant for Private Equity companies. Previously, he was the President, Aerospace Customers and Business Development of United Technologies in 2012. From 1996 to 2012, he held several positions of increasing responsibility at Goodrich, including Segment President for Actuation and Landing Systems and Segment President of Engine Systems and Group President for Engine/Safety/Electronic Systems. From 1977 to 1996, he held various engineering and general management positions at General Electric, including Manager of the M&I Engines Division’s Product Delivery Operation. He has been a director of Minerals Technologies Inc. since May 2013. He currently is a member of the Audit Committee and the Compensation Committee of Minerals Technologies Inc.

Paula H.J. Cholmondeley United States Director of MTI		Ms. Cholmondeley is a former Vice President and General Manager, Specialty Products from 2000 to 2004 of Sappi Fine Paper, North America, a producer of coated fine paper. Ms. Cholmondeley held senior positions with various companies from 1980 through 1998 including Owens Corning, The Faxon Company, Blue Cross of Greater Philadelphia, and Westinghouse Elevator Company, and also served as a White House Fellow assisting the U.S. Trade Representative during the Reagan administration. Ms. Cholmondeley, a former certified public accountant, is an alumnus of Howard University and received a Masters Degree in Accounting from the University of Pennsylvania, Wharton School of Finance. Member of the Board of Directors of Dentsply International Inc., Terex Corporation and Albany International Corp., and also a member of the audit committees of Albany and Nationwide Mutual Funds. Independent trustee of Nationwide Mutual Funds. She is a part-time member of the Board Services faculty of the National Association of Corporate Directors. She has been a director of Minerals Technologies Inc. since January 2005. She currently is a member of the Audit Committee and Chair of the Corporate Governance and Nominating Committee of Minerals Technologies Inc.


Name, Country of Citizenship, Position		Present Principal Occupation or Employment; Material Positions Held During the Past Five Years; Certain Other Information
Michael A. Cipolla United States Vice President, Corporate Controller and Chief Accounting Officer of MTI		Michael A. Cipolla was elected Vice President, Corporate Controller and Chief Accounting Officer in July 2003. Prior to that, he served as Corporate Controller and Chief Accounting Officer of MTI since 1998. From 1992 to 1998 he served as Assistant Corporate Controller.

Robert L. Clark United States Director of MTI		Mr. Clark is a professor and Dean of the School of Engineering and Applied Sciences, University of Rochester since September 2008 and Senior Vice President for Research since March 2013. He was dean of the Pratt School of Engineering at Duke University August 2007 to September 2008. Between 1992 and August 2007, he held increasing positions of academic responsibility at Duke University from Assistant Professor to Senior Associate Dean of Pratt School of Engineering and Chair, Mechanical Engineering and Materials Science. He currently is a director of Minerals Technologies Inc. and member of the Audit Committee and the Corporate Governance and Nominating Committee as of January 2010.

Douglas T. Dietrich United States Senior Vice President, Finance and Treasury, Chief Financial Officer of MTI and Director of Purchaser		Douglas T. Dietrich was elected Senior Vice President, Finance and Treasury, Chief Financial Officer of MTI effective January 1, 2011. He is also a director of Purchaser. Prior to that, he was appointed Vice President, Corporate Development and Treasury effective August 2007. He had been Vice President, Alcoa Wheel Products since 2006 and President, Alcoa Latin America Extrusions and Global Rod and Bar Products since 2002.

Duane R. Dunham United States Director of MTI		Mr. Dunham is the retired President and Chief Operating Officer of Bethlehem Steel Corporation since January 2002. He was the Chairman and Chief Executive Officer of Bethlehem Steel from April 2000 to September 2001. He was the President and Chief Operating Officer from 1999 to April 2000 and President of the Sparrows Point division from 1993 to 1999. He was a director of Bethlehem Steel Corporation from 1999 to 2002. He has been a director of Minerals Technologies Inc. since 2002. He is the Chair of the Compensation Committee and member of the Corporate Governance and Nominating Committee of Minerals Technologies Inc.

Jonathan J. Hastings United States Senior Vice President, Corporate Development of MTI and Director and President of Purchaser		Jonathan J. Hastings was elected Senior Vice President, Corporate Development of MTI effective March 2013. He is also currently a director and the President of Purchaser. Prior to that he was elected Vice President, Corporate Development, effective September 2011. Prior to that, he was Senior Director of Strategy and New Business Development—Coatings, Global at The Dow Chemical Company. Prior to that he held positions of increasing responsibility at Rohm and Haas, including Vice President & General Manager—Packaging and Building Materials—Europe.


Name, Country of Citizenship, Position		Present Principal Occupation or Employment; Material Positions Held During the Past Five Years; Certain Other Information
Douglas W. Mayger United States Senior Vice President, Performance Minerals and MTI Supply Chain		Douglas W. Mayger was elected Senior Vice President, Performance Minerals and MTI Supply Chain in June 2011. Prior to that, he was Vice President and Managing Director, Performance Minerals which encompasses the Processed Minerals product line and the Specialty PCC product line, effective October 2008. Prior to that, he was General Manager -Carbonates West, Performance Minerals and Business Manager—Western Region. Before joining MTI as plant manager in Lucerne Valley in 2002, he served as Vice President of Operations for Aggregate Industries.

Thomas J. Meek United States Senior Vice President, General Counsel, Human Resources, Secretary and Chief Compliance Officer of MTI and Director, Senior Vice President, General Counsel and Secretary of Purchaser.		Thomas J. Meek was elected Senior Vice President, General Counsel, Human Resources, Secretary and Chief Compliance Officer in October 2011. He is also currently a director and the Senior Vice President, General Counsel and Secretary of Purchaser. Prior to that, he was Vice President, General Counsel and Secretary of MTI effective September 2009. Prior to that, he served as Deputy General Counsel at Alcoa. Before joining Alcoa in 1999, Mr. Meek worked with Koch Industries, Inc. of Wichita, Kansas, where he held numerous supervisory positions. His last position there was Interim General Counsel. From 1985 to 1990, Mr. Meek was an Associate/Partner in the Wichita, Kansas law firm of McDonald, Tinker, Skaer, Quinn & Herrington, P.A.

D.J. Monagle, III United States Senior Vice President, Chief Operating Officer of MTI		D.J. Monagle, III was elected Senior Vice President, Chief Operating Officer, effective February 2014. In October 2008, he was appointed Senior Vice President and Managing Director, Paper PCC. In November 2007, he was appointed Vice President and Managing Director—Performance Minerals. He joined MTI in January of 2003 and held positions of increasing responsibility including Vice President, Americas, Paper PCC and Global Marketing Director, Paper PCC. Before joining MTI, Mr. Monagle worked for the Paper Technology Group at Hercules between 1990 and 2003, where he held sales and marketing positions of increasing responsibility. Between 1985 and 1990, he served as an aviation officer in the U.S. Army’s 11th Armored Cavalry Regiment, leaving the service as a troop commander with a rank of Captain.


Name, Country of Citizenship, Position		Present Principal Occupation or Employment; Material Positions Held During the Past Five Years; Certain Other Information
Joseph C. Muscari United States Chairman and Chief Executive Officer of MTI		Mr. Muscari was elected to resume his previous duties of Chairman and Chief Executive Officer, effective February 2014. He previously was the Executive Chairman of MTI from March 2013 to February 2014 and Chairman and Chief Executive Officer of MTI from March 2007 to March 2013. He was the Executive Vice President and Chief Financial Officer from January 1, 2006 to December 31, 2006 and Executive Vice President from January 1, 2007 to February 28, 2007 of Alcoa Inc., a producer of aluminum and aluminum products and components and other consumer products. He was the Executive Vice President, Alcoa Inc., and Group President-Rigid Packaging, Foil & Asia from 2004 to 2005; Executive Vice President and Group President, Asia & Latin America from 2001 to 2004; and Vice President Environment, Health, Safety, Audit and Compliance from 1997 to 2001 of Alcoa Inc. Director of Aluminum Corporation of China Limited 2002 to 2007. He has been a director of Dana Holding Corporation since May 2010. He has been a director of EnerSys since June 2008. He has been a director of Minerals Technologies Inc. since January 2005.

Marc E. Robinson United States Director of MTI		Mr. Robinson is a Senior Executive Advisor of Booz & Company as of December 2011. He was the Company Group Chairman of Johnson & Johnson from 2007 to September 2011. He was the Global President Consumer Healthcare Division of Pfizer from 2003 to 2006. He was the North American President Consumer Healthcare Division of Pfizer from 2000-2002. He was the Regional President, Australia and New Zealand of Warner-Lambert Company from 1999 to 2000. He was the General Manager European Business Process Improvement of Warner Lambert Company from 1996 to 1998. He was the Marketing Assistant, Assistant Product Manager of General Mills from 1984 to 1986. He is a member of the Capsugel Scientific and Business Advisory Board as of May 2012. He is a director of Minerals Technologies Inc. and member of the Audit Committee and the Corporate Governance and Nominating Committee as of January 2012.

Johannes C. Schut Netherlands Vice President and Managing Director, Minteq International		Johannes C. Schut was elected Vice President and Managing Director, Minteq International in March 2011. He joined MTI in 2004 as Director of Finance—Europe. In 2006, he was named Vice President, Minteq—Europe including Middle East and India. Before joining Minerals Technologies Inc., Mr. Schut held positions of increasing responsibility with Royal Phillips Electronics and Royal FrieslandCampina—DMV International.


Name, Country of Citizenship, Position		Present Principal Occupation or Employment; Material Positions Held During the Past Five Years; Certain Other Information
Barbara R. Smith United States Director of MTI		Ms. Smith is has been the Senior Vice President and Chief Financial Officer of Commercial Metals Company since June 2011. Ms. Smith was the Vice President and Chief Financial Officer of Gerdau Ameristeel from 2007-2011 and Treasurer beginning from July 2006. She was the Senior Vice President and Chief Financial Office of FARO Technologies, Inc. from February 2005 to July 2006. During the more than 20 prior years, Ms. Smith held positions of increasing financial leadership with Alcoa Inc. Ms. Smith has been a director of Minerals Technologies Inc. since May 2011. She is the Chair of the Audit Committee and member of the Compensation Committee of Minerals Technologies Inc.

Donald C. Winter, Ph. D. United States Director of MTI		Donald C. Winter, Ph. D. served as the 74th Secretary of the Navy from January 2006 to March 2009. As Secretary of the Navy, he led America’s Navy and Marine Corps Team and was responsible for an annual budget in excess of $125 billion. Previously, Dr. Winter held multiple positions in the aerospace and defense industry as a systems engineer, program manager and corporate executive. From 2000 to 2005, he was President and CEO of TRW Systems (later Northrop Grumman Mission Systems), which he joined in 1972. From 2010 to 2012, Dr. Winter served as chair of the National Academy of Engineering Committee charged with investigating the causes of the Deepwater Horizon Blowout for the Secretary of the Interior. He continues to consult and lecture on systems safety, worldwide.


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