SC 13D/A

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D/A

Under the Securities Exchange Act of 1934

(Amendment No. 19)*

PolyMet Mining Corp.

(Name of Issuer)

Common Shares, without par value

(Title of Class of Securities)

731916102

(CUSIP Number)

Stephen Rowland and Rajiv Singhal

Glencore International AG

Baarermattstrasse 3

CH-6341 Baar

Switzerland

+41 41 709 2000

With copies to:

Matias Vega, Esq.

Curtis, Mallet-Prevost, Colt & Mosle LLP

101 Park Avenue

New York, NY 10178

(212) 696-6000

(Name, Address and Telephone Number of Person

Authorized to Receive Notices and Communications)

October 28, 2016

(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box. ¨

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See §240.13d-7 for other parties to whom copies are to be sent.

^* The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

Page 2 of 22

CUSIP No. 731916102

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (entities only) Glencore plc
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) ¨ (b) ¨
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS): AF (see Item 3)
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(D) OR 2(E)
6	CITIZEN OR PLACE OF ORGANIZATION Jersey

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 0
	8	SHARED VOTING POWER 138,480,565
	9	SOLE DISPOSITIVE POWER 0
	10	SHARED DISPOSITIVE POWER 138,480,565

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 138,480,565
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 38.1%
14	TYPE OF REPORTING PERSON CO; HC

Page 3 of 22

CUSIP No. 731916102

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (entities only) Glencore International AG
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) ¨ (b) ¨
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS): WC (see Item 3)
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(D) OR 2(E)
6	CITIZEN OR PLACE OF ORGANIZATION Switzerland

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 0
	8	SHARED VOTING POWER 138,480,565
	9	SOLE DISPOSITIVE POWER 0
	10	SHARED DISPOSITIVE POWER 138,480,565

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 138,480,565
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 38.1%
14	TYPE OF REPORTING PERSON CO; HC

Page 4 of 22

CUSIP No. 731916102

1	NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (entities only) Glencore AG
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) ¨ (b) ¨
3	SEC USE ONLY
4	SOURCE OF FUNDS (SEE INSTRUCTIONS): WC (see Item 3)
5	CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(D) OR 2(E)
6	CITIZEN OR PLACE OF ORGANIZATION Switzerland

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 0
	8	SHARED VOTING POWER 138,480,565
	9	SOLE DISPOSITIVE POWER 0
	10	SHARED DISPOSITIVE POWER 138,480,565

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 138,480,565
12	CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 38.1%
14	TYPE OF REPORTING PERSON CO

Page 5 of 22

Explanatory Note:

This Amendment No. 19 (this “Amendment No. 19”) amends and restates the Schedule 13D originally filed with the United States Securities and Exchange Commission (the “SEC”) by Glencore Holding AG, Glencore International AG and Glencore AG on November 10, 2008, and amended by Amendment No. 1 thereto filed on December 24, 2008, Amendment No. 2 thereto filed on June 22, 2009, Amendment No. 3 thereto filed on September 4, 2009, Amendment No. 4 thereto filed on November 3, 2009, Amendment No. 5 thereto filed on November 23, 2009, Amendment No. 6 thereto filed on January 27, 2010, Amendment No. 7 thereto filed on November 15, 2010, Amendment No. 8 thereto filed on June 2, 2011 (which amendment removed Glencore Holding AG as a Reporting Person and added Glencore International plc (now known as Glencore plc) as a Reporting Person), Amendment No. 9 thereto filed on July 15, 2011, Amendment No. 10 thereto filed on December 6, 2011, Amendment No. 11 thereto filed on October 16, 2012, Amendment No. 12 thereto filed on April 16, 2013, Amendment No. 13 thereto filed on June 10, 2013, Amendment No. 14 thereto filed on July 8, 2013, Amendment No. 15 thereto filed on April 29, 2014, Amendment No. 16 thereto filed on August 5, 2015, Amendment No. 17 thereto filed on December 18, 2015 and Amendment No. 18 thereto filed on September 19, 2016 (as so amended, the “Statement”) relating to the common shares, no par value (“Common Shares”), of PolyMet Mining Corp., a corporation incorporated under the laws of the Province of British Columbia, Canada (the “Issuer”). This Amendment No. 19 reflects changes to Items 3, 5 and 7 of the Statement.

Item 1 Security and Issuer

This Schedule 13D relates to the common shares, without par value (the “Common Shares”), of PolyMet Mining Corp., a corporation incorporated under the laws of the Province of British Columbia, Canada. The Issuer’s principal executive office is located at First Canadian Place, 100 King Street West, Suite 5700, Toronto, Ontario Canada M5X 1C7.

Item 2 Identity and Background

This Schedule 13D is being filed by (a) Glencore plc (formerly known as Glencore Xstrata plc) (“Glencore plc”), (b) Glencore International AG (“Glencore International”) and (c) Glencore AG (collectively, the “Reporting Persons”). Glencore plc is a company organized under the laws of Jersey. Each of Glencore International and Glencore AG is a company organized under the laws of Switzerland.

Glencore plc is a public company with its ordinary shares listed on the London Stock Exchange and on the Hong Kong Stock Exchange. Glencore plc is the parent company of Glencore International which, together with its subsidiaries, including Glencore AG, is a leading integrated producer and marketer of commodities, with worldwide activities in the marketing of metals and minerals, energy products and agricultural products and the production, refinement, processing, storage and transport of these products. Each of the Reporting Persons other than Glencore plc is a direct or indirect wholly-owned subsidiary of Glencore plc. Glencore AG is a direct wholly-owned subsidiary of Glencore International.

The address of the principal business and office of each of the Reporting Persons is Baarermattstrasse 3, CH-6341 Baar, Switzerland.

The name, citizenship, occupation and principal business address of each director and executive officer of the Reporting Persons are listed in Schedule 1 hereto (the “Schedule 1 Persons”), which Schedule 1 is incorporated herein by reference.

During the last five years, none of the Reporting Persons, or, to the Reporting Persons’ knowledge, any of the Schedule 1 Persons, has been (i) convicted in a criminal proceeding (excluding traffic violations and similar misdemeanors) or (ii) party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

Page 6 of 22

Item 3. Source and Amount of Funds or Other Consideration

On October 31, 2008, Glencore AG, the Issuer and the Issuer’s wholly owned subsidiary, Poly Met Mining, Inc., a Minnesota corporation (the “Issuer Subsidiary”), entered into a purchase agreement (the “Original Purchase Agreement”), as amended by a letter agreement (“Amendment No. 1”), dated as of November 28, 2008, and as further amended by a letter agreement (“Amendment No. 2”), dated as of December 12, 2008, a letter agreement (“Amendment No. 3”), dated as of December 19, 2008, a letter agreement (“Amendment No. 4”), dated as of January 30, 2009, a letter agreement (“Amendment No. 5”), dated as of February 24, 2009, a letter agreement (“Amendment No. 6”), dated as of March 30, 2009, a letter agreement (“Amendment No. 7”), dated as of April 28, 2009, a letter agreement (“Amendment No. 8”), dated as of June 4, 2009, a letter agreement (“Amendment No. 9”), dated as of August 31, 2009, a letter agreement (“Amendment No. 10”), dated as of October 20, 2009, and a letter agreement (“Amendment No. 11”), dated as of November 16, 2009 (the Original Purchase Agreement, as amended, the “Purchase Agreement”), which provided for, among other things, Glencore AG’s purchase of up to US$50,000,000 in aggregate principal amount of floating rate secured debentures due September 30, 2011 issued by the Issuer Subsidiary (collectively, the “Debentures”).

The initial closing of the transactions contemplated by the Original Purchase Agreement occurred on October 31, 2008. At the initial closing, the Issuer Subsidiary issued to Glencore AG an initial tranche of US$7,500,000 of the Debentures (the “Tranche A Debenture”). Subsequently, the Issuer Subsidiary issued to Glencore AG a second tranche of US$7,500,000 of the Debentures (the “Tranche B Debenture”) on December 22, 2008, a third tranche of US$5,000,000 of the Debentures (the “Tranche C Debenture”) on June 17, 2009 and a fourth tranche of US$5,000,000 of the Debentures (the “Tranche D Debenture”) on August 31, 2009. The Original Purchase Agreement had also provided for a fifth tranche of US$25,000,000 of the Debentures (the “Tranche E Debenture”) to be issued to Glencore AG upon the satisfaction of additional closing conditions set forth in the Original Purchase Agreement.

The Tranche A Debenture, the Tranche B Debenture, the Tranche C Debenture and the Tranche D Debenture initially bore interest at a rate equal to the 12-month US dollar LIBOR plus 4%. Interest is payable in cash or by increasing the principal amount of such Debentures. On or before September 30, 2009, the Issuer was able to elect in which form to make the interest payments; thereafter, Glencore AG may make such election. As of September 30, 2016, approximately US$15 million of capitalized and accrued interest had been added to the principal amount of such Debentures. The Issuer has guaranteed the Issuer Subsidiary’s obligations under such Debentures pursuant to a Parent Guarantee (the “Parent Guarantee”), dated as of October 31, 2008. The Issuer Subsidiary’s obligations under such Debentures are secured by (i) the assets of the Issuer pursuant to a security agreement (the “Issuer Security Agreement”), dated as of October 31, 2008, between the Issuer and Glencore AG, (ii) the assets of the Issuer Subsidiary pursuant to a security agreement (the “Issuer Subsidiary Security Agreement”), dated as of October 31, 2008, between the Issuer Subsidiary and Glencore AG, and (iii) a security interest in the Issuer’s equity interest in the Issuer Subsidiary pursuant to a pledge agreement (the “Pledge Agreement”), dated as of October 31, 2008, between the Issuer and Glencore AG.

In connection with the Original Purchase Agreement, on October 31, 2008, the Issuer issued to Glencore AG an exchange warrant pursuant to which the Debentures were exchangeable into Common Shares at any time at an exchange rate of US$4.00 per Common Share for the Tranche A Debenture, the Tranche B Debenture, the Tranche C Debenture and the Tranche D Debenture, and an exchange rate of US$2.65 per Common Share for the Tranche E Debenture (the “Original Exchange Warrant”).

In connection with the Original Purchase Agreement, on October 31, 2008, the Issuer issued to Glencore AG a purchase warrant entitling Glencore AG to purchase 6,250,000 Common Shares at an exercise price of US$3.00 per Common Share (the “2008 Purchase Warrant”).

Page 7 of 22

Concurrently with the issuance of the Tranche A Debenture and the 2008 Purchase Warrant, the Issuer and Glencore AG entered into a Registration Rights Agreement (the “2008 Registration Rights Agreement”). The 2008 Registration Rights Agreement granted Glencore AG demand and piggyback registration rights with respect to Common Shares issuable upon exercise of the Original Exchange Warrant and/or exercise of the 2008 Purchase Warrant.

Pursuant to a subscription agreement, dated as of November 17, 2009, between Glencore AG and the Issuer (the “First 2009 Subscription Agreement”), Glencore AG acquired from the Issuer, on a private placement basis, 3,773,585 Common Shares for an aggregate purchase price of US$10,000,000.25 (or US$2.65 per Common Share). Pursuant to another subscription agreement, dated as of November 23, 2009, between Glencore AG and the Issuer (the “Second 2009 Subscription Agreement”), on January 26, 2010, Glencore AG acquired from the Issuer, on a private placement basis, 5,660,377 Common Shares for an aggregate purchase price of US$14,999,999.05 (or US$2.65 per Common Share).

On November 12, 2010, the Issuer, the Issuer Subsidiary and Glencore AG entered into an amendment and waiver agreement (the “2010 Amendment and Waiver”) pursuant to which the parties agreed, among other things, to:

· terminate and discharge the Issuer Subsidiary’s obligation to issue, and Glencore AG’s obligation to purchase, the Tranche E Debenture;

· extend the maturity date for each of the Tranche A Debenture, the Tranche B Debenture, the Tranche C Debenture and the Tranche D Debenture from September 30, 2011 to September 30, 2012;

· extend the expiration date of the Original Exchange Warrant from September 30, 2011 to September 30, 2012; and

· cancel the 2008 Purchase Warrant and cause the Issuer to issue to Glencore a new warrant to purchase up to 3,000,000 Common Shares at an exercise price of US$2.00 per share.

On November 12, 2010, as contemplated by the 2010 Amendment and Waiver, the Issuer issued to Glencore AG a purchase warrant entitling Glencore AG to purchase 3,000,000 Common Shares at an exercise price of US$2.00 per Common Share until December 31, 2015 (the “2010 Purchase Warrant”).

In accordance with the terms of the 2010 Amendment and Waiver, the Issuer and Glencore AG also entered into a registration rights agreement, dated as of November 12, 2010 (the “2010 Registration Rights Agreement”), pursuant to which Glencore AG (and any transferee of Common Shares to whom Glencore AG transfers its registration rights) was granted demand and piggyback registration rights with respect to all Common Shares held by Glencore AG, including any Common Shares issuable upon exercise of the 2010 Purchase Warrant and/or exercise of the Original Exchange Warrant. The 2010 Registration Rights Agreement provides that the Issuer must effect an unlimited number of demand registration rights if holders of at least fifty percent (50%) of such registrable securities demand the registration of Common Shares covering at least twenty-five percent (25%) of the outstanding amount of such registrable securities (or a lesser percent if the anticipated aggregate offering price, net of underwriting discounts and commissions, would exceed US$5,000,000); provided, however, the Issuer is not obligated to effect (i) a registration covering the sale of Common Shares for an aggregate public offering price of less than US$5,000,000, (ii) more than two such registrations in any twelve-month period or (iii) any registration at a time when it is keeping three such registration statements effective.

Concurrently, Glencore AG and the Issuer entered into a Subscription Agreement, dated as of November 12, 2010 (the “2010 Subscription Agreement”), pursuant to which Glencore AG agreed to purchase from the Issuer, on a private placement basis, an aggregate of 15,000,000 Common Shares for a purchase price of US$2.00 per Common Share in three separate tranches of 5,000,000 Common Shares each.

Page 8 of 22

On January 17, 2011, pursuant to the first tranche of the 2010 Subscription Agreement, Glencore AG acquired from the Issuer, on a private placement basis, 5,000,000 Common Shares for an aggregate purchase price of US$10,000,000 (or US$2.00 per Common Share).

The Issuer’s board of directors waived applicable provisions of the Issuer’s amended and restated shareholder rights plan agreement with respect to Glencore AG’s purchase of the remaining second and third tranches of the 2010 Subscription Agreement.

On July 15, 2011, pursuant to the second tranche of the 2010 Subscription Agreement, Glencore AG acquired an additional 5,000,000 Common Shares from the Issuer for an aggregate purchase price of US$10,000,000 (or US$2.00 per Common Share). Concurrently, Glencore AG granted a waiver to the Issuer pursuant to which Glencore AG waived the application of certain covenants contained in the Tranche A Debenture, the Tranche B Debenture, the Tranche C Debenture and the Tranche D Debenture to the secured loan provided by the Iron Range Resources and Rehabilitation Board to the Issuer Subsidiary that previously closed on June 28, 2011 (the “IRRRB Loan Waiver”).

On October 15, 2012, pursuant to the remaining third tranche of the 2010 Subscription Agreement, Glencore AG acquired an additional 5,000,000 Common Shares from the Issuer for an aggregate purchase price of US$10,000,000 (or US$2.00 per Common Share).

On July 15, 2011, Glencore AG acquired pursuant to a private transaction 9,200,547 Common Shares at a price of US$1.4233 per share. These shares were purchased from Cliffs Erie L.L.C. (“Cliffs”) in accordance with the Issuer’s right to arrange for a purchaser of the shares upon notice from Cliffs of its desire to sell the shares. The purchase was made pursuant to a share purchase agreement, which was previously filed with the SEC as an exhibit to the Statement, and is hereby incorporated herein by reference.

In connection with Glencore AG’s purchase from Cliffs, the Issuer’s board of directors waived applicable provisions of the Issuer’s amended and restated shareholder rights plan agreement with respect to Glencore AG becoming the beneficial owner of more than 20% of the outstanding voting shares of the Issuer as a result of the purchases described above.

On December 6, 2011, pursuant to a subscription agreement, dated as of November 30, 2011, between Glencore AG and the Issuer (the “2011 Subscription Agreement”), Glencore AG acquired from the Issuer, on a private placement basis, an aggregate of 13,333,333 Common Shares and a warrant entitling Glencore AG to purchase up to an aggregate of 2,600,000 Common Shares at an exercise price of US$1.50 per Common Share until December 31, 2015 (the “2011 Purchase Warrant”) for an aggregate purchase price of US$19,999,999.50.

In connection with the 2011 Subscription Agreement, on December 6, 2011, an amendment and waiver agreement, dated as of November 30, 2011, among the Issuer, the Issuer Subsidiary and Glencore AG (the “2011 Amendment and Waiver”), became effective and amended, among other things:

· each of the Tranche A Debenture, the Tranche B Debenture, the Tranche C Debenture and the Tranche D Debenture to extend the maturity date from September 30, 2012 to the earlier of (i) the date which is 10 business days after the date on which the Issuer and/or the Issuer Subsidiary has received all permits required to commence construction of the NorthMet mine and Erie Plant facilities in St. Louis County, Minnesota in a form reasonably acceptable to Glencore AG (the “NorthMet Project”) and the senior construction financing for the NorthMet Project is made available to the Issuer and/or the Issuer Subsidiary in a form reasonably acceptable to Glencore AG (collectively, the “Construction Prerequisites”) and (ii) September 30, 2014;

Page 9 of 22

· each of the Tranche A Debenture, the Tranche B Debenture, the Tranche C Debenture and the Tranche D Debenture to prohibit the Issuer from redeeming such Debentures prior to the Issuer and/or the Issuer Subsidiary satisfying the Construction Prerequisites;

· the 2010 Purchase Warrant to reduce the exercise price from US$2.00 to US$1.50 per Common Share; and

· the 2010 Purchase Warrant to include a mandatory exercise feature if the 20-day volume weighted average price of the Common Shares is equal to or greater than 150% of the exercise price and the Issuer provides notice to Glencore AG that it has obtained the Construction Prerequisites.

In addition, pursuant to the 2011 Amendment and Waiver, on December 6, 2011, the Issuer issued to Glencore AG an amended and restated exchange warrant that amended and restated the Original Exchange Warrant (the “Amended and Restated Exchange Warrant”). Pursuant to the Amended and Restated Exchange Warrant, the Tranche A Debenture, the Tranche B Debenture, the Tranche C Debenture and the Tranche D Debenture are exchangeable into Common Shares at an exchange rate of US$1.50 per Common Share for such Debentures at any time until the earlier of (i) the Issuer and/or the Issuer Subsidiary satisfying the Construction Prerequisites and (ii) September 30, 2014. The Amended and Restated Exchange Warrant further provides that the Issuer may, within 10 business days after the date on which the Issuer and/or the Issuer Subsidiary has satisfied the Construction Prerequisites, deliver a notice to Glencore AG requiring Glencore AG to exercise the Amended and Restated Exchange Warrant.

In addition, in connection with the 2011 Subscription Agreement and the 2011 Amendment and Waiver, on November 30, 2011, the Issuer and Glencore AG entered into a registration rights agreement and amendment to existing registration rights agreement (the “2011 Registration Rights Agreement”), pursuant to which (i) Glencore AG (and any transferee of Common Shares to whom Glencore AG transfers its registration rights) was granted demand and piggyback registration rights with respect to the Common Shares issued under the 2011 Subscription Agreement and the Common Shares issuable upon exercise of the 2011 Purchase Warrant and (ii) the 2010 Registration Rights Agreement was amended so that the registrable securities covered by the 2010 Registration Rights Agreement include the Common Shares issuable upon exercise of the 2010 Purchase Warrant, as amended by the 2011 Amendment and Waiver, and the Common Shares issuable upon exercise of the Amended and Restated Exchange Warrant.

The Issuer’s board of directors waived applicable provisions of the Issuer’s amended and restated shareholder rights plan agreement with respect to the transactions contemplated by the 2011 Subscription Agreement and the 2011 Amendment and Waiver.

On April 11, 2013, Glencore AG loaned US$20 million to the Issuer Subsidiary through the purchase of an amended Tranche E Debenture from the Issuer Subsidiary (as amended, the “Amended Tranche E Debenture”) pursuant to an amendment to the Purchase Agreement, dated as of April 10, 2013 (the “Amendment No. 14 to Purchase Agreement”), among the Issuer, the Issuer Subsidiary and Glencore AG. The Amended Tranche E Debenture had a maturity date of May 1, 2014, subject to mandatory repayment upon closing of the Rights Offering and carried a fixed interest rate of 4.721% per annum. Pursuant to a confirmation of secured obligations agreement (the “Confirmation of Secured Obligations Agreement”), dated as of April 10, 2013, among the Issuer Subsidiary, the Issuer and Glencore AG, the parties had confirmed that the Issuer Subsidiary’s obligations under the Amended Tranche E Debenture were guaranteed by the Issuer and secured by the assets of the Issuer and the Issuer Subsidiary on the same terms as the Tranche A Debenture, the Tranche B Debenture, the Tranche C Debenture and the Tranche D Debenture. On July 5, 2013, the Amended Tranche E Debenture was fully repaid with proceeds from the Rights Offering (as described below).

Page 10 of 22

On July 5, 2013, at the closing of an offering of rights (“Rights”) by the Issuer to holders of Common Shares to raise up to approximately US$60.5 million in gross proceeds (the “Rights Offering”) contemplated by a standby purchase agreement, dated as of April 10, 2013, between Glencore AG and the Issuer (the “Standby Purchase Agreement”), Glencore AG acquired from the Issuer 31,756,979 Common Shares for an aggregate purchase price of US$20,959,606.14 (or US$0.66 per Common Share), of which 23,483,921 Common Shares were acquired by Glencore AG pursuant to the exercise of its basic subscription privilege under the Rights Offering and 8,273,058 Common Shares of which were acquired by Glencore AG pursuant to the exercise of its additional subscription privilege under the Rights Offering. In consideration for Glencore AG’s agreement to provide a standby commitment for the Rights Offering pursuant to the Standby Purchase Agreement, Glencore AG received a cash fee of approximately US$1.06 million at the closing of the Rights Offering. In addition, on July 5, 2013, at the closing of the Rights Offering, the Issuer and Glencore AG entered into (i) a corporate governance agreement (the “Corporate Governance Agreement”) under which, effective January 1, 2014, Glencore AG may appoint that number of the directors of the Issuer which is proportionate to Glencore AG’s ownership of Common Shares (on a fully diluted basis), subject to certain limitations including that Glencore AG may not appoint more than 49% (rounding down) of the Issuer’s directors and (ii) a registration rights agreement (the “2013 Registration Rights Agreement”) pursuant to which Glencore AG (and any transferee of Common Shares to whom Glencore AG transfers its registration rights) was granted demand and piggyback registration rights with respect to all Common Shares acquired by Glencore AG pursuant to the Rights Offering.

Glencore AG waived its right of first refusal on material financings by the Issuer contained in the 2010 Subscription Agreement with respect to the Rights Offering. In addition, the Issuer’s board of directors waived applicable provisions of the Issuer’s amended and restated shareholder rights plan agreement with respect to Glencore AG in connection with (i) the issuance of the Rights and Common Shares issuable upon exercise of the Rights under the Rights Offering and (ii) the Standby Purchase Agreement.

At the closing of the Rights Offering, as a result of the Rights Offering’s triggering of customary anti-dilution provisions: (i) the exchange rate at which the Tranche A Debenture, the Tranche B Debenture, the Tranche C Debenture and the Tranche D Debenture are exchangeable pursuant to the Amended and Restated Exchange Warrant was reduced from US$1.50 to US$1.2920 per Common Share, (ii) the exercise prices for the 2010 Purchase Warrant and the 2011 Purchase Warrant were reduced from US$1.50 to US$1.3007 per Common Share and (iii) the number of Common Shares issuable upon exercise of the 2010 Purchase Warrant and the 2011 Purchase Warrant were increased to 3,459,643 Common Shares and 2,998,358 Common Shares, respectively.

On April 25, 2014, the Issuer, the Issuer Subsidiary and Glencore AG entered into an amendment agreement (the “2014 Amendment”) pursuant to which the parties agreed, among other things, to:

· extend the maturity date for each of the Tranche A Debenture, the Tranche B Debenture, the Tranche C Debenture and the Tranche D Debenture to the earlier to occur of (i) the Issuer giving Glencore AG ten days’ notice that it has received permits necessary to start construction of the NorthMet Project and availability of senior construction finance, in a form reasonably acceptable to Glencore AG (the “Early Maturity Event”) and (ii) September 30, 2015; and

· extend the expiration date of the Amended and Restated Exchange Warrant to the earlier to occur of (i) the Early Maturity Event and (ii) September 30, 2015.

On January 28, 2015, the Issuer, the Issuer Subsidiary and Glencore AG entered into an amendment to the Purchase Agreement (the “Amendment No. 16 to Purchase Agreement”) pursuant to which the parties agreed, among other things, for the Issuer Subsidiary to issue to Glencore AG new Tranche F, G, H, and I debentures (the “2015 Debentures”) with the total principal amount of US$30.0 million. Tranche F in the principal amount of US$8.0 million was issued on January 30, 2015. Tranche G in the principal amount of $8.0 million was issued on April 15, 2015. Tranche H in the principal amount of US$8.0 million was issued on July 1, 2015. Tranche I in the principal amount of US$6 million was issued on October 1, 2015. The 2015 Debentures bear interest at 12-month US dollar LIBOR plus 8.0% per annum payable in cash upon maturity and were issued with an initial maturity date of the earlier of (i) the availability of at least US$100 million of finance provided the Issuer demonstrates repayment is prudent or (ii) March 31, 2016. The Issuer and the Issuer Subsidiary provided security by way of a guarantee and a pledge of the assets of the Issuer and the Issuer Subsidiary.

Page 11 of 22

On July 30, 2015, the Issuer, the Issuer Subsidiary and Glencore AG entered into an amendment to the Purchase Agreement (the “Amendment No. 17 to Purchase Agreement”) pursuant to which the parties agreed, among other things, to:

· extend the maturity date for each of the Tranche A Debenture, the Tranche B Debenture, the Tranche C Debenture and the Tranche D Debenture to the earlier to occur of (i) the Early Maturity Event and (ii) March 31, 2016;

· extend the expiration date of the Amended and Restated Exchange Warrant to the earlier to occur of (i) the Early Maturity Event and (ii) March 31, 2016;

· adjust, as of August 1, 2015, the interest rate of the Tranche A Debenture, the Tranche B Debenture, the Tranche C Debenture and the Tranche D Debenture to US dollar LIBOR plus 8%; and

· amend the 2010 Purchase Warrant and the 2011 Purchase Warrant such that (i) the exercise price has been reduced to US$0.9292 per share and (ii) the expiration date has been extended to December 31, 2016 subject to mandatory exercise if the 20-day VWAP of the Common Shares is equal to or greater than 150% of the exercise price or the occurrence of the Early Maturity Event.

On December 15, 2015, the Issuer, the Issuer Subsidiary and Glencore AG entered into an amendment to the Purchase Agreement (the “Amendment No. 18 to Purchase Agreement”) pursuant to which the parties agreed, among other things, to:

· extend the maturity date of the Tranche A Debenture, the Tranche B Debenture, the Tranche C Debenture and the Tranche D Debenture to the earlier of (i) the availability of at least US$80 million of debt or equity financing, (ii) March 31, 2017 or (iii) such earlier date upon acceleration or by redemption or repayment (defined as the date on which the Issuer elects to repay the outstanding principal and unpaid and accrued interest thereunder provided that the Issuer can demonstrate that such early repayment is prudent and provided that the Issuer has provided to Glencore AG with ten business days’ notice of such early repayment);

· adjust the interest rate of the Tranche A Debenture, the Tranche B Debenture, the Tranche C Debenture and the Tranche D Debenture to US dollar LIBOR plus 15%;

· subject to approval by the Toronto Stock Exchange and the NYSE MKT, extend the expiration date of the Amended and Restated Exchange Warrant to be the same as the maturity date of the Tranche A Debenture, the Tranche B Debenture, the Tranche C Debenture and the Tranche D Debenture;

· subject to approval by the Toronto Stock Exchange and the NYSE MKT, amend the 2010 Purchase Warrant and the 2011 Purchase Warrant such that (i) the exercise price is reduced to US$0.8231 per share and (ii) the expiration date is extended to December 31, 2017 (which remains subject to mandatory exercise if the 20-day VWAP of the Common Shares is equal to or greater than 150% of the exercise price or the occurrence of the Early Maturity Event);

· extend the maturity date of the 2015 Debentures to the earlier of (i) the availability of at least US$80 million of debt or equity financing or (ii) March 31, 2017; and

· adjust the interest rate of the 2015 Debentures to US dollar LIBOR plus 15%.

Page 12 of 22

On January 27, 2016, the Issuer, the Issuer Subsidiary and Glencore AG entered into an amendment to the Purchase Agreement (the “Amendment No. 19 to Purchase Agreement”) pursuant to which the parties agreed for the Issuer Subsidiary to issue to Glencore AG a new Tranche J Debenture in the principal amount of US$11.0 million (the “Tranche J Debenture”). The Tranche J Debenture was issued on January 27, 2016. The Tranche J Debenture bears interest at 12-month US dollar LIBOR plus 15.0% per annum payable in cash upon maturity and were issued with an initial maturity date of the earlier of (i) the availability of at least US$80 million of debt or equity financing or (ii) March 31, 2017.

On June 2, 2016, the Issuer, the Issuer Subsidiary and Glencore AG entered into an amendment to the Purchase Agreement (the “Amendment No. 20 to Purchase Agreement”) pursuant to which the parties agreed for the Issuer Subsidiary to issue to Glencore AG new Tranche K, L and M debentures (the “KLM Debentures”) in the aggregate principal amount of US$14.0 million. Tranche K in the principal amount of US$3.0 million was issued on June 3, 2016. On June 30, 2016, the Issuer Subsidiary and Glencore AG entered into an amendment to the Purchase Agreement (the “Amendment No. 21 to Purchase Agreement”) pursuant to which the parties agreed for the Issuer Subsidiary to issue the Tranche L debenture to Glencore AG in two tranches, a Tranche L-1 debenture and a Tranche L-2 debenture. The Tranche L-1 debenture in the principal amount of US$5.0 million was issued on July 1, 2016. The Tranche L-2 debenture in the principal amount of US$3.0 million was issued on July 26, 2016. The Tranche M debenture in the principal amount of US$3.0 million was issued on August 5, 2016. The KLM Debentures bear interest at 12-month US dollar LIBOR plus 15.0% per annum payable in cash upon maturity and were issued with an initial maturity of the earlier of (i) the availability of at least US$100 million of debt or equity financing or (ii) March 31, 2017.

On September 14, 2016, the Issuer, the Issuer Subsidiary and Glencore AG entered into an amendment to the Purchase Agreement (the “Amendment No. 22 to Purchase Agreement”) pursuant to which the parties agreed to extend the maturity date of the Tranche A Debenture, the Tranche B Debenture, the Tranche C Debenture, the Tranche D Debenture, the 2015 Debentures, the Tranche J Debenture and the KLM Debentures to the earlier of (i) the availability of at least US$100 million of debt and/or equity financing or (ii) March 31, 2018.

On October 24, 2016, the Issuer, the Issuer Subsidiary and Glencore AG entered into an amendment to the Purchase Agreement (the “Amendment No. 23 to Purchase Agreement”) pursuant to which:

· the parties agreed to amend the Amended and Restated Exchange Warrant so that the exchange rate at which the Tranche A Debenture, the Tranche B Debenture, the Tranche C Debenture and the Tranche D Debenture are exchangeable pursuant to the Amended and Restated Exchange Warrant was reduced from US$1.2920 to US$1.2696 per Common Share;

· the Issuer agreed to issue to Glencore AG a warrant entitling Glencore AG to purchase up to an aggregate of 625,000 Common Shares at an exercise price of US$0.7797 per Common Share until October 28, 2021 (the “First 2016 Purchase Warrant”) in partial consideration for the extensions of the maturity date contemplated by Amendment No. 22 to Purchase Agreement; and

· the Issuer agreed to pay Glencore AG a fixed fee equal to US$730,000 for certain advisory services.

The First 2016 Purchase Warrant was issued on October 28, 2016.

On October 28, 2016, in connection with Glencore’s exercise of its right to maintain its pro rata ownership following the Issuer’s private placement that closed on October 18, 2016, pursuant to a subscription agreement between Glencore AG and the Issuer (the “2016 Subscription Agreement”), Glencore AG acquired from the Issuer, on a private placement basis, an aggregate of 14,111,251 Common Shares and a warrant entitling Glencore AG to purchase up to an aggregate of 7,055,626 Common Shares at an exercise price of US$1.00 per Common Share until October 28, 2021 (the “Second 2016 Purchase Warrant”) for an aggregate purchase price of US$10,583,438.25.

Page 13 of 22

The foregoing summaries of the Original Purchase Agreement, Amendment No. 1, Amendment No. 2, Amendment No. 3, Amendment No. 4, Amendment No. 5, Amendment No. 6, Amendment No. 7, Amendment No. 8, Amendment No. 9, Amendment No. 10, Amendment No. 11, the Tranche A Debenture, the Tranche B Debenture, the Tranche C Debenture, the Tranche D Debenture, the Parent Guarantee, the Issuer Security Agreement, the Issuer Subsidiary Security Agreement, the Pledge Agreement, the Original Exchange Warrant, the 2008 Purchase Warrant, the 2008 Registration Rights Agreement, the First 2009 Subscription Agreement, the Second 2009 Subscription Agreement, the 2010 Amendment and Waiver, the 2010 Purchase Warrant, the 2010 Registration Rights Agreement, the 2010 Subscription Agreement, the IRRRB Loan Waiver, the 2011 Subscription Agreement, the 2011 Purchase Warrant, the 2011 Amendment and Waiver, the Amended and Restated Exchange Warrant, the 2011 Registration Rights Agreement, the Amended Tranche E Debenture, the Amendment No. 14 to Purchase Agreement, the Confirmation of Secured Obligations Agreement, the Standby Purchase Agreement, the Corporate Governance Agreement, the 2013 Registration Rights Agreement, the 2014 Amendment, the Amendment No. 16 to Purchase Agreement, the Amendment No. 17 to Purchase Agreement, the Amendment No. 18 to Purchase Agreement, the Amendment No. 19 to Purchase Agreement, the Amendment No. 20 to Purchase Agreement, the Amendment No. 21 to Purchase Agreement and the Amendment No. 22 to Purchase Agreement do not purport to be complete and are qualified in their entirety by reference to the complete text of such agreements, which were previously filed with the SEC as exhibits to the Statement, and are hereby incorporated herein by reference. The foregoing summaries of the Amendment No. 23 to Purchase Agreement, the First 2016 Purchase Warrant, the 2016 Subscription Agreement and the Second 2016 Purchase Warrant do not purport to be complete and are qualified in their entirety by reference to the complete text of such agreements, which have been attached as Exhibits 99.52, 99.53, 99.54 and 99.55, respectively, to this Amendment No. 19 and are hereby incorporated herein by reference.

The source of funds for all of the purchases described above was working capital of the Reporting Persons. The Reporting Persons anticipate that the source of funds for any exercises of the 2010 Purchase Warrant, the 2011 Purchase Warrant, the First 2016 Purchase Warrant and/or the Second 2016 Purchase Warrant will be working capital of the Reporting Persons.

Item 4. Purpose of Transaction

The Reporting Persons acquired the securities of the Issuer covered by this Schedule 13D for investment purposes. The Reporting Persons intend to continue to evaluate the Issuer’s business, financial condition, results of operations, capital structure, management, stock market performance, competitive outlook and other relevant factors. As part of such evaluations, the Reporting Persons may seek the views of, hold discussions with and respond to inquiries from representatives of the Issuer and other persons regarding the Issuer’s affairs. Depending on such evaluations, each Reporting Person may at any time and from time to time acquire Common Shares or securities convertible or exchangeable for Common Shares; dispose of Common Shares which it has acquired; and/or enter into privately negotiated derivative transactions with institutional counterparts to hedge the market risk of some or all of the positions in the Common Shares which it has acquired. Any acquisition or disposition of Common Shares by the Reporting Persons may be effected through open market or privately negotiated transactions, or otherwise. Any such transactions may be effected at any time and from time to time subject to any applicable limitations of the United States Securities Act of 1933, as amended. In the interest of maximizing shareholder value, the Reporting Persons may, from time to time, develop plans respecting, or propose changes in the management, policies, operations, capital structure or business of the Reporting Persons. Such plans or proposals may include or relate to one or more of the transactions specified in Items 4(a) through (j) of Schedule 13D under Rule 13d-1(a), including without limitation, a merger, disposition, sale of the Issuer’s assets or changes in the Issuer’s capitalization. Each Reporting Person reserves the right to change its plans and intentions at any time, as it deems appropriate.

Page 14 of 22

Stephen Rowland, who is an employee of Glencore AG, is a member of the Issuer’s board of directors and also serves on the Issuer’s Technical Steering Committee and as an ex-officio member on the Issuer’s Nominating and Corporate Governance committee. Matthew Daley, who is an employee of Glencore AG, is a member of the Issuer’s board of directors and also serves on the Issuer’s Technical Steering Committee and the Issuer’s Safety, Health and Environmental Committee.

As described in Item 3 of the Statement, on July 5, 2013, the Issuer and Glencore AG entered into the Corporate Governance Agreement under which, effective January 1, 2014, Glencore AG may appoint that number of the directors of the Issuer which is proportionate to Glencore AG’s ownership of Common Shares (on a fully diluted basis), subject to certain limitations including that Glencore AG may not appoint more than 49% (rounding down) of the Issuer’s directors.

Except as described herein, neither the Reporting Persons, nor, to the Reporting Persons’ knowledge, any of the Schedule 1 Persons has any present plans or proposals that relate to or would result in any of the actions described in Items 4(a) through (j) of Schedule 13D under Rule 13d-1(a). To the Reporting Persons’ knowledge, any of the Schedule 1 Persons may make the same evaluation and reserve the same rights.

Item 5. Interest in Securities of the Issuer

(a) and (b)

The Reporting Persons collectively own, directly or indirectly, 92,836,072 Common Shares. However, the Reporting Persons may be deemed to collectively have direct or indirect “beneficial ownership” within the meaning of Rule 13d-3 under the United States Securities Exchange Act of 1934, as amended (the “Exchange Act”), of (i) an additional 31,505,866 Common Shares issuable upon exercise of the Amended and Restated Exchange Warrant (based on the principal amount of the Debentures that includes capitalized and accrued interest as of September 30, 2016), (ii) an additional 3,459,643 Common Shares issuable upon exercise of the 2010 Purchase Warrant, (iii) an additional 2,998,358 Common Shares issuable upon exercise of the 2011 Purchase Warrant, (iv) an additional 625,000 Common Shares issuable upon exercise of the First 2016 Purchase Warrant and (v) an additional 7,055,626 Common Shares issuable upon exercise of the Second 2016 Purchase Warrant. Accordingly, each of the Reporting Persons may be deemed to beneficially own an aggregate of 138,480,565 Common Shares, representing 38.1% of the Issuer’s issued and outstanding Common Shares. This beneficial ownership percentage assumes that there are 363,512,617 Common Shares outstanding, which was calculated based on the sum of (i) 277,793,706 Common Shares outstanding on September 9, 2016 as reported by the Issuer in its Management Discussion and Analysis for the three and six months ended July 31, 2016, filed as Exhibit 99.2 to the Issuer’s Report on Form 6-K furnished with the SEC on September 15, 2016, (ii) the 25,963,167 Common Shares issued in the Issuer’s private placement that closed on October 18, 2016, (iii) the 14,111,251 Common Shares issued to Glencore AG pursuant to the 2016 Subscription Agreement, (iv) the 31,505,866 Common Shares issuable upon exercise of the Amended and Restated Exchange Warrant (based on the principal amount of the Debentures that includes capitalized and accrued interest as of September 30, 2016), (v) the 3,459,643 Common Shares issuable upon exercise of the 2010 Purchase Warrant, (vi) the 2,998,358 Common Shares issuable upon exercise of the 2011 Purchase Warrant, (vii) the 625,000 Common Shares issuable upon exercise of the First 2016 Purchase Warrant and (viii) the 7,055,626 Common Shares issuable upon exercise of the Second 2016 Purchase Warrant. The Reporting Persons share the power to vote or to direct the vote and dispose or to direct the disposition of the 138,480,565 Common Shares set forth above.

(c)           Except as set forth in Item 3 and this Item 5 of the Statement, none of the Reporting Persons nor, to the Reporting Persons’ knowledge, any of the Schedule 1 Persons, has beneficial ownership of any other Common Shares, or has engaged in any other transaction during the past 60 days in any Common Shares.

Mr. Stephen Rowland, who is a member of the Issuer’s board of directors and an employee of Glencore AG, owns 179,762 Common Shares and holds options to purchase 750,000 Common Shares and restricted share units in respect of 52,879 Common Shares. Matthew Daley, who is a member of the Issuer’s board of directors and an employee of Glencore AG, holds options to purchase 250,000 Common Shares and restricted share units in respect of 52,879 Common Shares.

Page 15 of 22

(d)           Not applicable.

(e)           Not applicable.

Item 6 Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer

Except as set forth in Item 3 of the Statement, to the best knowledge of the Reporting Persons, there are no other contracts, arrangements, understandings or relationships (legal or otherwise) among the persons named in Item 2 or between such persons and any other person with respect to any securities of the Issuer, including but not limited to, transfer or voting of any of the securities of the Issuer, joint ventures, loan or option arrangements, puts or calls, guarantees of profits, division of profits or loss, or the giving or withholding of proxies, or a pledge or contingency the occurrence of which would give another person voting power over the securities of the Issuer.

Item 7 Material to Be Filed as Exhibits

Exhibit No.	Description
99.1	Joint Filing Agreement, dated October 31, 2016, between Glencore plc, Glencore International AG and Glencore AG relating to the filing of this Amendment No. 19.
99.2	Purchase Agreement (incorporated by reference to Exhibit No. 99.2 to the Schedule 13D filed with the SEC on November 10, 2008).
99.3	Floating Rate Secured Debenture (incorporated by reference to Exhibit No. 99.3 to the Schedule 13D filed with the SEC on November 10, 2008).
99.4	Parent Guarantee (incorporated by reference to Exhibit No. 99.4 to the Schedule 13D filed with the SEC on November 10, 2008).
99.5	Security Agreement (incorporated by reference to Exhibit No. 99.5 to the Schedule 13D filed with the SEC on November 10, 2008).
99.6	Security Agreement (incorporated by reference to Exhibit No. 99.6 to the Schedule 13D filed with the SEC on November 10, 2008).
99.7	Pledge Agreement (incorporated by reference to Exhibit No. 99.7 to the Schedule 13D filed with the SEC on November 10, 2008).
99.8	Exchange Warrant of PolyMet Mining Corp. (incorporated by reference to Exhibit No. 99.8 to the Schedule 13D filed with the SEC on November 10, 2008).
99.9	Purchase Warrant of PolyMet Mining Corp. (incorporated by reference to Exhibit No. 99.9 to the Schedule 13D filed with the SEC on November 10, 2008).
99.10	Registration Rights Agreement (incorporated by reference to Exhibit No. 99.10 to the Schedule 13D filed with the SEC on November 10, 2008).
99.11	Amendment No. 1 relating to the Purchase Agreement (incorporated by reference to Exhibit No. 99.11 to the Schedule 13D/A filed with the SEC on December 24, 2008).
99.12	Amendment No. 2 relating to the Purchase Agreement (incorporated by reference to Exhibit No. 99.12 to the Schedule 13D/A filed with the SEC on December 24, 2008).

Page 16 of 22

99.13	Amendment No. 3 relating to the Purchase Agreement (incorporated by reference to Exhibit No. 99.13 to the Schedule 13D/A filed with the SEC on December 24, 2008).
99.14	Floating Rate Secured Debenture, due September 30, 2011 (incorporated by reference to Exhibit No. 99.14 to the Schedule 13D/A filed with the SEC on December 24, 2008).
99.15	Amendment No. 4 relating to the Purchase Agreement (incorporated by reference to Exhibit No. 99.15 to the Schedule 13D/A filed with the SEC on June 22, 2009).
99.16	Amendment No. 5 relating to the Purchase Agreement (incorporated by reference to Exhibit No. 99.16 to the Schedule 13D/A filed with the SEC on June 22, 2009).
99.17	Amendment No. 6 relating to the Purchase Agreement (incorporated by reference to Exhibit No. 99.17 to the Schedule 13D/A filed with the SEC on June 22, 2009).
99.18	Amendment No. 7 relating to the Purchase Agreement (incorporated by reference to Exhibit No. 99.18 to the Schedule 13D/A filed with the SEC on June 22, 2009).
99.19	Amendment No. 8 relating to the Purchase Agreement (incorporated by reference to Exhibit No. 99.19 to the Schedule 13D/A filed with the SEC on June 22, 2009).
99.20	Floating Rate Secured Debenture, due September 30, 2011 (incorporated by reference to Exhibit No. 99.20 to the Schedule 13D/A filed with the SEC on June 22, 2009).
99.21	Amendment No. 9 relating to the Purchase Agreement (incorporated by reference to Exhibit No. 99.21 to the Schedule 13D/A filed with the SEC on September 4, 2009).
99.22	Floating Rate Secured Debenture, due September 30, 2011 (incorporated by reference to Exhibit No. 99.22 to the Schedule 13D/A filed with the SEC on September 4, 2009).
99.23	Amendment No. 10 relating to the Purchase Agreement (incorporated by reference to Exhibit No. 99.23 to the Schedule 13D/A filed with the SEC on November 3, 2009).
99.24	Amendment No. 11 relating to the Purchase Agreement (incorporated by reference to Exhibit No. 99.24 to the Schedule 13D/A filed with the SEC on November 23, 2009).
99.25	Subscription Agreement (incorporated by reference to Exhibit No. 99.25 to the Schedule 13D/A filed with the SEC on November 23, 2009).
99.26	Subscription Agreement (incorporated by reference to Exhibit No. 99.26 to the Schedule 13D/A filed with the SEC on November 23, 2009).
99.27	Amendment and Waiver Agreement, dated as of November 12, 2010, by and between PolyMet Mining Corp. and Glencore AG (incorporated by reference to Exhibit No. 99.27 to the Schedule 13D/A filed with the SEC on November 15, 2010).
99.28	Non-Transferable Common Share Purchase Warrant of PolyMet Mining Corp., dated November 12, 2010 (incorporated by reference to Exhibit No. 99.28 to the Schedule 13D/A filed with the SEC on November 15, 2010).

Page 17 of 22

99.29	Registration Rights Agreement, dated as of November 12, 2010, by and between PolyMet Mining Corp. and Glencore AG (incorporated by reference to Exhibit No. 99.29 to the Schedule 13D/A filed with the SEC on November 15, 2010).
99.30	Subscription Agreement, dated as of November 12, 2010, by and between PolyMet Mining Corp. and Glencore AG (incorporated by reference to Exhibit No. 99.30 to the Schedule 13D/A filed with the SEC on November 15, 2010).
99.31	Waiver, dated as of July 14, 2011, from Glencore AG (incorporated by reference to Exhibit No. 31 to the Schedule 13D/A filed with the SEC on July 15, 2011).
99.32	Share Purchase Agreement, dated as of July 14, 2011, by and between Cliffs Erie L.L.C. and Glencore AG (incorporated by reference to Exhibit No. 32 to the Schedule 13D/A filed with the SEC on July 15, 2011).
99.33	Subscription Agreement, dated as of November 30, 2011, by and between PolyMet Mining Corp. and Glencore AG (incorporated by reference to Exhibit No. 99.33 to the Schedule 13D/A filed with the SEC on December 6, 2011).
99.34	Non-Transferable Common Share Purchase Warrant of PolyMet Mining Corp., dated December 6, 2011 (incorporated by reference to Exhibit No. 99.34 to the Schedule 13D/A filed with the SEC on December 6, 2011).
99.35	Amendment and Waiver Agreement, dated as of November 30, 2011, by and between PolyMet Mining Corp. and Glencore AG (incorporated by reference to Exhibit No. 99.35 to the Schedule 13D/A filed with the SEC on December 6, 2011).
99.36	Amended and Restated Exchange Warrant of PolyMet Mining Corp (incorporated by reference to Exhibit No. 99.36 to the Schedule 13D/A filed with the SEC on December 6, 2011).
99.37	Registration Rights Agreement and Amendment to Existing Registration Rights Agreement, dated as of November 30, 2011, by and between PolyMet Mining Corp. and Glencore AG (incorporated by reference to Exhibit No. 99.37 to the Schedule 13D/A filed with the SEC on December 6, 2011).
99.38	Standby Purchase Agreement, dated as of April 10, 2013, by and between PolyMet Mining Corp. and Glencore AG (incorporated by reference to Exhibit No. 99.38 to the Schedule 13D/A filed with the SEC on April 16, 2013).
99.39	Amendment No. 14 Relating to Purchase Agreement, dated as of April 10, 2013, by and among PolyMet Mining Corp., Poly Met Mining, Inc. and Glencore AG (incorporated by reference to Exhibit No. 99.39 to the Schedule 13D/A filed with the SEC on April 16, 2013).
99.40	Fixed Rate Secured Debenture, due no later than May 1, 2014 (incorporated by reference to Exhibit No. 99.40 to the Schedule 13D/A filed with the SEC on April 16, 2013).

Page 18 of 22

99.41	Confirmation of Secured Obligations Agreement, dated as of April 10, 2013, by Poly Met Mining, Inc., PolyMet Mining Corp. and Glencore AG (incorporated by reference to Exhibit No. 99.41 to the Schedule 13D/A filed with the SEC on April 16, 2013).
99.42	Corporate Governance Agreement, dated as of July 5, 2013, by and between PolyMet Mining Corp. and Glencore AG (incorporated by reference to Exhibit No. 99.42 to the Schedule 13D/A filed with the SEC on July 8, 2013).
99.43	Registration Rights Agreement, dated as of July 5, 2013, by and between PolyMet Mining Corp. and Glencore AG (incorporated by reference to Exhibit No. 99.43 to the Schedule 13D/A filed with the SEC on July 8, 2013).
99.44	Amendment Agreement, dated as of April 25, 2014, by and among PolyMet Mining Corp., Poly Met Mining, Inc. and Glencore AG (incorporated by reference to Exhibit No. 99.44 to the Schedule 13D/A filed with the SEC on April 29, 2014).
99.45	Amendment No. 16 Relating to Purchase Agreement, dated as of January 28, 2015, by and among PolyMet Mining Corp., Poly Met Mining, Inc. and Glencore AG (incorporated by reference to Exhibit No. 99.45 to the Schedule 13D/A filed with the SEC on August 5, 2015).
99.46	Amendment No. 17 Relating to Purchase Agreement, dated as of July 30, 2015, by and among PolyMet Mining Corp., Poly Met Mining, Inc. and Glencore AG (incorporated by reference to Exhibit No. 99.46 to the Schedule 13D/A filed with the SEC on August 5, 2015).
99.47	Amendment No. 18 Relating to Purchase Agreement, dated as of December 15, 2015, by and among PolyMet Mining Corp., Poly Met Mining, Inc. and Glencore AG (incorporated by reference to Exhibit No. 99.47 to the Schedule 13D/A filed with the SEC on December 18, 2015).
99.48	Amendment No. 19 Relating to Purchase Agreement, dated as of January 27, 2016, by and among PolyMet Mining Corp., Poly Met Mining, Inc. and Glencore AG (incorporated by reference to Exhibit No. 99.48 to the Schedule 13D/A filed with the SEC on September 19, 2016).
99.49	Amendment No. 20 Relating to Purchase Agreement, dated as of June 2, 2016, by and among PolyMet Mining Corp., Poly Met Mining, Inc. and Glencore AG (incorporated by reference to Exhibit No. 99.49 to the Schedule 13D/A filed with the SEC on September 19, 2016).
99.50	Amendment No. 21 Relating to Purchase Agreement, dated as of June 30, 2016, by and among PolyMet Mining Corp., Poly Met Mining, Inc. and Glencore AG (incorporated by reference to Exhibit No. 99.50 to the Schedule 13D/A filed with the SEC on September 19, 2016).
99.51	Amendment No. 22 Relating to Purchase Agreement, dated as of September 14, 2016, by and among PolyMet Mining Corp., Poly Met Mining, Inc. and Glencore AG (incorporated by reference to Exhibit No. 99.51 to the Schedule 13D/A filed with the SEC on September 19, 2016).
99.52	Amendment No. 23 Relating to Purchase Agreement, dated as of October 24, 2016, by and among PolyMet Mining Corp., Poly Met Mining, Inc. and Glencore AG.

Page 19 of 22

99.53	First 2016 Purchase Warrant, dated October 28, 2016, issued by PolyMet Mining Corp. to Glencore AG.
99.54	Subscription Agreement, dated as of October 28, 2016, by and between PolyMet Mining Corp. and Glencore AG.
99.55	Second 2016 Purchase Warrant, dated October 28, 2016, issued by PolyMet Mining Corp. to Glencore AG.

Page 20 of 22

Signature

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: October 31, 2016

Glencore AG
By:	/s/ Patrick Huber
Name:	Patrick Huber
Title:	Officer
By:	/s/ Andreas Hubmann
Name:	Andreas Hubmann
Title:	Director

Glencore International AG
By:	/s/ Andreas Hubmann
Name:	Andreas Hubmann
Title:	Director
By:	/s/ Shaun Teichner
Name:	Shaun Teichner
Title:	Officer

Glencore plc
By:	/s/ John Burton
Name:	John Burton
Title:	Company Secretary

Page 21 of 22

SCHEDULE 1

Set forth below are the names, business addresses and present principal occupations of the directors and executive officers of Glencore plc, Glencore International AG and Glencore AG. Each executive officer of each of Glencore International AG and Glencore AG is also a director of such company. Where no business address is given for an executive officer or director, and such director’s principal employer is Glencore plc or one of its subsidiaries, the business address is Baarermattstrasse 3, CH-6341, Baar, Switzerland. To the best knowledge of the Reporting Persons, none of the persons listed below beneficially owns any shares of Common Shares.

Directors of Glencore plc:

Name	Principal Occupation	Business address	Share Ownership
Ivan Glasenberg (Citizen of Switzerland)	Chief Executive Officer
Anthony Hayward (Citizen of the United Kingdom)	Director, Genel Energy	1 Grafton Street, London W1S 4FE United Kingdom
Peter Coates (Citizen of Australia)	Non-Executive Chairman, Santos Ltd	Level 22, The Gateway Building 1 Macquarie Place Sydney NSW 2000 Australia
Leonhard Fischer (Citizen of Germany)	Chief Executive Officer, BHF Kleinwort Benson Group SA	Avenue Louise 326 1050 Brussels Belgium
Peter Grauer (Citizen of USA)	Executive Chairman Bloomberg LP	731 Lexington Avenue New York, New York 10022 USA
William Macaulay (Citizen of USA)	Chairman and Chief Executive Officer, First Reserve Corporation	One Lafayette Place Greenwich, Connecticut 06830 USA
John Mack (Citizen of USA)	Senior advisor to Morgan Stanley	6 Club Road Rye, New York 10580 USA
Patrice Merrin (Citizen of Canada)	Non-Executive Director	Glencore International AG Baarermattstrasse 3 CH-6341 Baar Switzerland

Executive Officers of Glencore plc:

Name	Principal Occupation	Business address	Share Ownership
Ivan Glasenberg (Citizen of Switzerland)	Chief Executive Officer
Steven Kalmin (Citizen of Australia)	Chief Financial Officer
John Burton (Citizen of the United Kingdom)	Company Secretary

Page 22 of 22

Directors and Executive Officers of Glencore International AG:

Name	Principal Occupation	Business address	Share Ownership
Ivan Glasenberg (Citizen of Switzerland)	Chief Executive Officer
Steven Kalmin (Citizen of Australia)	Chief Financial Officer
Andreas P. Hubmann (Citizen of Switzerland)	Accountant

Directors and Executive Officers of Glencore AG:

Name	Principal Occupation	Business address	Share Ownership
Martin W. Haering (Citizen of Switzerland)	Tax Officer
Carlos Perezagua (Citizen of Spain)	Chairman and Chief Risk Officer
Andreas P. Hubmann (Citizen of Switzerland)	Accountant

EX-99.1

EXHIBIT 99.1

JOINT FILING AGREEMENT

Each of the undersigned hereby agrees that this Amendment No. 19 to the statement on Schedule 13D is being filed with the United States Securities and Exchange Commission on behalf of each of the undersigned pursuant to Rule 13d-1(k) under the United States Securities Exchange Act of 1934, as amended.

Dated: October 31, 2016

Glencore AG
By:	/s/ Patrick Huber
Name:	Patrick Huber
Title:	Officer
By:	/s/ Andreas Hubmann
Name:	Andreas Hubmann
Title:	Director

Glencore International AG
By:	/s/ Andreas Hubmann
Name:	Andreas Hubmann
Title:	Director
By:	/s/ Shaun Teichner
Name:	Shaun Teichner
Title:	Officer

Glencore plc
By:	/s/ John Burton
Name:	John Burton
Title:	Company Secretary

EX-99.52

Exhibit 99.52 

AMENDMENT NO. 23 RELATING TO PURCHASE AGREEMENT

            This Amendment Agreement (this "Agreement"), is made as of the 24^th day of October, 2016, by and among POLYMET MINING CORP., a company existing under the laws of British Columbia (the "Company"), POLY MET MINING, INC., a corporation existing under the laws of the State of Minnesota (the "Issuer"), and GLENCORE AG, a corporation existing under the laws of Switzerland (the "Purchaser").

RECITALS

            WHEREAS, the Company and the Issuer are seeking to develop the NorthMet Project located in St. Louis County, Minnesota, U.S.A.;

            WHEREAS, the Company, the Issuer and the Purchaser are parties to that certain Purchase Agreement, dated as of October 31, 2008, as amended by Letter Agreement, dated November 28, 2008, as further amended by Amendment Letter No. 2, dated December 12, 2008, as further amended by Amendment Letter No. 3, dated December 19, 2008, as further amended by Amendment Letter No. 4, dated January 30, 2009, as further amended by Amendment Letter No. 5, dated February 24, 2009, as further amended by Amendment Letter No. 6, dated March 30, 2009, as further amended by Amendment Letter No. 7, dated April 28, 2009, as further amended by Amendment Letter No. 8, dated June 4, 2009, as further amended by Amendment Letter No. 9, dated August 31, 2009, as further amended by Amendment Letter No. 10, dated October 20, 2009, as further amended by Amendment Letter No. 11, dated November 16, 2009, as further amended by the 2010 Amendment and Waiver (as defined below), as further amended by the 2011 Amendment and Waiver (as defined below), as further amended by Amendment Letter No. 14, dated April 10, 2013 (“Amendment No. 14”), as further amended by the 2014 Amendment and Waiver (as defined below), as further amended by Amendment Letter No. 16 dated January 29, 2015 (“Amendment No. 16”), as further amended by Amendment Letter No. 17 dated July 30, 2015 (“Amendment No. 17”), as further amended by Amendment Letter No. 18 dated December 15, 2015 (“Amendment No. 18”), as further amended by Amendment Letter No. 19 dated January 27, 2016 (“Amendment 19”), as further amended by Amendment Letter No. 20 dated June 2, 2016 (“Amendment 20”), as further amended by Amendment Letter No. 21 dated June 30, 2016 (“Amendment 21”), and as further amended by Amendment Letter No. 22 dated September 14, 2016 (“Amendment 22”) (as defined below) (as amended, supplemented or otherwise modified from time to time, the "Purchase Agreement");

            WHEREAS, pursuant to the Purchase Agreement, among other things, (1) the Issuer agreed to issue Floating Rate Secured Debentures due September 30, 2011 (each, a "Debenture" and collectively, the "Debentures") in five separate tranches, consisting of four Debentures in the aggregate principal amount of US$25,000,000 and a fifth Debenture in the principal amount of US$25,000,000 (the "Original Tranche E Debenture"), in each case to be issued and delivered by the Issuer and paid for by the Purchaser upon fulfillment or waiver of certain conditions set forth therein; and (2) the Company issued (i) a warrant, exercisable from time to time (the "Exchange Warrant"), to purchase common shares of the Company, without par value (the "Common Shares"), in an amount equal to the principal amount of the Debentures divided by US$4.00;

            WHEREAS, (1) the first Debenture in the original principal amount of US$7,500,000 (the "Tranche A Debenture") was issued to the Purchaser on October 31, 2008; (2) the second Debenture in the original principal amount of US$7,500,000 (the "Tranche B Debenture") was issued to the Purchaser on December 24, 2008; (3) the third Debenture in the original principal amount of US$5,000,000 (the "Tranche C Debenture") was issued to the Purchaser on June 18, 2009; (4) the fourth Debenture in the original principal amount of US$5,000,000 (the "Tranche D Debenture" and together with the Tranche A Debenture, Tranche B Debenture and Tranche C Debenture, the "Outstanding Debentures") was issued to the Purchaser on September 2, 2009;

            WHEREAS, the Company, the Issuer and the Purchaser entered into an Amendment and Waiver, dated as of November 12, 2010 (the "2010 Amendment and Waiver"), pursuant to which, among other things, (1) the maturity date of each of the Outstanding Debentures and the expiration date of the Exchange Warrant were extended from September 30, 2011 to September 30, 2012, (2) any and all obligations of the Issuer to issue the Original Tranche E Debenture and any and all obligations of the Purchaser to purchase the Original Tranche E Debenture pursuant to the Purchase Agreement were terminated and discharged in all respects (the "Original Tranche E Debenture Termination"), and (3) the Company issued to the Purchaser a warrant to purchase 3,000,000 Common Shares at an exercise price of US$2.00 per share at any time until December 31, 2015 (the “2010 Warrant’);

            WHEREAS, the Company, the Issuer and the Purchaser entered into an Amendment and Waiver, dated as of November 30, 2011 (the "2011 Amendment and Waiver"), pursuant to which, among other things, (1) the maturity date of each of the Outstanding Debentures was extended from September 30, 2012 to the earlier to occur of certain events or September 30, 2014, (2) the exercise price of the Exchange Warrants was amended to US$1.50 per share, (3) the Company issued to the Purchaser warrants to purchase up to an aggregate of 2,600,000 Common Shares at an exercise price of US$1.50 per share at any time until December 31, 2015 (the “2011 Warrants”), and (4) the terms of the 2010 Warrants were amended to conform to the 2011 Warrants;

            WHEREAS, the Company, the Issuer and the Purchaser rescinded the Original Tranche E Debenture Termination and amended the obligations of the Issuer pursuant to the Purchase Agreement to issue a fifth Debenture in the principal amount of US$20,000,000 (the "Amended Tranche E Debenture") and the obligations of the Purchaser to purchase the Amended Tranche E Debenture pursuant to the Purchase Agreement, on the terms and subject to the conditions contained in Agreement Letter No. 14;

            WHEREAS, the Amended Tranche E Debenture were repaid in full on July 4, 2013;

            WHEREAS, on July 4, 2013, pursuant to Amendment No. 14, the exercise price of the Exchange Warrants was amended to US$1.2920 per share and the exercise price of the 2010 Warrants and the 2011 Warrants was amended to US$1.3007 per share;

            WHEREAS, the Company, the Issuer and the Purchaser entered into an Amendment and Waiver, dated as of April 25, 2014 (the "2014 Amendment and Waiver"), pursuant to which, among other things, the maturity date of each of the Outstanding Debentures was extended from the earlier to occur of certain events or September 30, 2014 to the earlier to occur of the same certain events or September 30, 2015;

            WHEREAS, on January 29, 2015, the Company, the Issuer and the Purchaser entered into Amendment No. 16 pursuant to which, among other things, the Issuer issued to the Purchaser a tranche F debenture (the “Tranche F Debenture”), and the Issuer and the Purchaser agreed to issue a tranche G debenture (the “Tranche G Debenture”), a tranche H debenture (the “Tranche H Debenture”) and a tranche I debenture (the “Tranche I Debenture,” and collectively with the Tranche F Debenture, the Tranche G Debenture and the Tranche H Debenture, the “2015 Debentures”) in the aggregate principal amount of US$30,000,000 pursuant to the Purchase Agreement;

            WHEREAS, the Tranche F Debenture was issued and fully paid for on January 30, 2015 and the Tranche G Debenture was issued and fully paid for on April 15, 2015 and the Tranche H Debenture was issued and fully paid for on July 1, 2015 and the Tranche I Debenture was issued and fully paid for on October 1, 2015;

            WHEREAS, on July 30, 2015, the Company, the Issuer and the Purchaser entered into Amendment No. 17 pursuant to which, among other things, (1) the maturity date of each of the Outstanding Debentures and the expiration date of the Exchange Warrant was extended from the earlier to occur of certain events or September 30, 2015 to the earlier to occur of the same certain events or March 31, 2016; (2) the Outstanding Debenture Floating Rate was reset to LIBOR plus 8.0% per annum with effect from August 1, 2015; and (3) the terms of the 2010 Warrants and the 2011 Warrants were amended such that their expiry date was extended to December 31, 2016 before 5:00 p.m. (Vancouver time) and the exercise price was amended to US$0.9292 per share;

            WHEREAS, On December 15, 2015, the Company, the Issuer and the Purchaser entered into Amendment No. 18 (“Amendment No. 18”) pursuant to which, among other things, (1) the maturity date of each of the Outstanding Debentures was extended from the earlier to occur of certain events or March 31, 2016 to the earlier of (i) the availability of at least Eighty Million U.S. Dollars (US$80,000,000) of debt or equity financing, or (ii) March 31, 2017 or (iii) such earlier date upon acceleration or by redemption or repayment (“Early Repayment Date”) as subsequently defined as the date on which the Issuer elects to repay the outstanding principal and unpaid and accrued interest thereunder provided that the Issuer can demonstrate that such early repayment is prudent and provided that the Issuer has provided to the Purchaser with ten (10) business days’ notice of such early repayment; (2) the Expiration Date of the Exchange Warrant was extended to the maturity date of the Outstanding Debentures; (3) the maturity date of each of the 2015 Debentures was extended from the earlier to occur of certain events or March 31, 2016 to the earlier of (i) the availability of at least Eighty Million U.S. Dollars (US$80,000,000) of debt or equity financing, or (ii) March 31, 2017; (4) the Outstanding Debentures and the 2015 Debentures floating rate was reset to LIBOR plus 15.0% with effect from January 1, 2016; and (5), the terms of the 2010 Warrants and the 2011 Warrants were amended such that their expiry date was extended to December 31, 2017 before 5:00 p.m. (Vancouver time) and the exercise price was amended to US$0.8231 per share;

            WHEREAS, on January 17, 2016, the Company, the Issuer and the Purchaser entered into Amendment No. 19 pursuant to which, among other things, the Issuer issued to the Purchaser a tranche J debenture (the “Tranche J Debenture”) in the aggregate principal amount of US$11,000,000 pursuant to the Purchase Agreement;

            WHEREAS, on June 2, 2016, the Company, the Issuer and the Purchaser entered into Amendment No. 20 pursuant to which, among other things, the Issuer issued to the Purchaser a tranche K debenture (the “Tranche K Debenture”), and the Issuer and the Purchaser agreed to issue a tranche L debenture (the “Tranche L Debenture”) and a tranche M debenture (the “Tranche M Debenture,”) in the aggregate principal amount of US$14,000,000 pursuant to the Purchase Agreement;

            WHEREAS, on June 30, 2016, the Company, the Issuer and the Purchaser entered into Amendment No. 21 pursuant to which, among other things, the Issuer agreed to issue and the Purchaser agreed to purchase the Tranche L Debenture in two tranches, the Tranche L-1 Debenture in the principal amount of US$5,000,000 (the “Tranche L-1 Debenture”) and the Tranche L-2 Debenture in the principal amount of US$3,000,000 (the “Tranche L-2 Debenture”, and together with the Tranche J Debenture, the Tranche K Debenture, the Tranche M Debenture, and the Tranche L-1 Debenture, the “2016 Debentures”) pursuant to the Purchase Agreement, on the terms and subject to the conditions contained in this Agreement;

            WHEREAS, on July 26, 2016, the Company, the Issuer and the Purchaser agreed an interim financing plan and the Issuer and the Purchaser agreed to proceed with the purchase and sale of the Tranche L-2 Debenture;

            WHEREAS, on September 14, 2016, the Company, the Issuer and the Purchaser entered into Amendment No. 22 pursuant to which, among other things, the parties agreed to extend the maturity date of the Debentures, as defined therein, and amend the interim financing plan;

            WHEREAS, on October 18, 2016 the Company issued and sold 25,963,167 common share units (the “Common Share Units”) at US$0.75 per Unit, each Unit consisting of one Common Share and one half of one common share purchase warrant exercisable at US$1.00 per share by way of private placement through a bought deal with Paradigm Capital Inc. and directly with existing shareholders of the Company and placed 660,005 broker warrants exercisable at US$0.83 per share (the “Placement”);

            WHEREAS, the Purchaser has the right to purchase its pro rata share of the Placement and has entered into a subscription agreement (“2016 Subscription Agreement” attached hereto as Appendix A) to purchase 14,111,251 units (the “Purchase Units”) on the same terms as the Common Share Units;

            WHEREAS, the Exchange Warrant contains a provision that requires an adjustment to the exercise price, as a result of certain events, including in the event the Company issues, wholly for cash, any Common Shares for a price per Common Share that is less than 100%, of the current market price of the Common Shares on the business day immediately preceding the date of the first public announcement of such issue or grant; and

            WHEREAS, the Company wishes to pay the Purchaser an advisory fee for providing assistance and advice to the Company regarding metal markets, financial markets, and financial structuring in connection with construction finance for the NorthMet Project and to issue to the Purchaser, as partial consideration for the Purchaser extending the maturity date of the Outstanding Debentures, the 2015 Debentures and the 2016 Debentures pursuant to Amendment No. 22, warrants to purchase Common Shares;

            NOW THEREFORE, in consideration of the terms and conditions contained in this Agreement, and other good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the parties, intending to be legally bound hereby, agree as follows:

1.	Definitions
	Capitalized terms not defined in this Agreement shall have the meanings ascribed to such terms in the Purchase Agreement.
2.	Amendment to the Purchase Agreement
	The Company, the Issuer and the Purchaser hereby agree to amend the Purchase Agreement from and after the Effective Date as follows notwithstanding any contrary provision therein:

(a)	The following definitions shall be added to Section 1:
	"Amendment No. 23 to the Purchase Agreement means the amending agreement made as of October 24, 2016 by and among the Company, the Issuer and the Purchaser”;

3.	Amendment to the Amended and Restated Exchange Warrant
	Pursuant to Section 12(f) of the Exchange Warrant, the exercise price of the Exchange Warrant shall be adjusted by a factor (“Anti-Dilution Factor”) of 0.9827 to US$1.2696 per share.
	For further clarity, the issuance of the Common Share Units does not trigger an adjustment to the purchase price of the 2010 Warrants and the 2011 Warrants.
4.	Incentive to amend the Outstanding Debentures, the 2015 Debentures and the 2016 Debentures
	Pursuant to Amendment No. 22 the Company, the Issuer, and the Purchaser agreed to extend the maturity date of the Outstanding Debentures, the 2015 Debentures, and the 2016 Debentures, subject to regulatory approval. For clarity, pursuant to Amendment No. 22, the expiration date of the Exchange Warrant was extended, subject to regulatory approval, such that it continues to be the same as the maturity date of the Outstanding Debentures.
	As partial consideration for amending the Outstanding Debentures, the 2015 Debentures and the 2016 Debentures, the Company agrees to issue to the Purchaser warrants (the “2016 Warrants” attached hereto as Appendix B) to purchase 625,000 Common Shares on the same terms and conditions as the warrants comprising the Common Share Units except that the exercise price shall be US$0.7797, the 5-day volume weighted average closing price of the Common Shares on the NYSE MKT on the date hereof.

5.	Compensation for Advisory Services
	As the Company and the Issuer proceed with financing for construction of the NorthMet Project, commencing on August 8, 2016 they have been receiving and will continue to request assistance and advice from Glencore including in connection with markets for the Company’s products, financing, financial assurance markets, and corporate strategy. The Company agrees to pay the Purchaser a fixed fee equal to US$730,000 for these service, payment due on the Closing Date.
6.	Effectiveness
	This Agreement shall become effective and be deemed effective as of the date hereof upon execution of counterparts of this Agreement by each of the Company, the Issuer and the Purchaser.
7.	Representations and Warranties of the Company and the Issuer

a. Each of the Company and the Issuer hereby confirms the representations and warranties in the Purchase Agreement are true and accurate as if the representation and warranty was given as of the date hereof and makes the following additional representations and warranties to the Purchaser:

(i) Authorization; Enforcement. Each of the Company and the Issuer has the requisite corporate power and authority to enter into and to consummate the transactions contemplated by this Agreement and otherwise to carry out its obligations hereunder. The execution and delivery of this Agreement by the Company and the Issuer and the consummation by the Company and the Issuer of the transactions contemplated hereby have been duly authorized by all necessary action on the part of the Company and the Issuer and no further action is required by the Company and the Issuer, their boards of directors or their shareholders in connection herewith. This Agreement has been duly executed by the Company and the Issuer and, when delivered in accordance with the terms hereof, will constitute the valid and binding obligation of the Company and the Issuer enforceable against the Company and the Issuer in accordance with its terms except (i) as limited by general equitable principles and applicable bankruptcy, insolvency, reorganization, moratorium and other laws of general application affecting enforcement of creditors' rights generally, (ii) as limited by laws relating to the availability of specific performance, injunctive relief or other equitable remedies, and (iii) insofar as indemnification and contribution provisions may be limited by applicable law.

b. The Purchaser hereby makes the following representations and warranties to the Company and the Issuer:

(i) Authorization; Enforcement. The Purchaser has the requisite corporate power and authority to enter into and to consummate the transactions contemplated by this Agreement and otherwise to carry out its obligations hereunder. The execution and delivery of this Agreement by the Purchaser and the consummation by the Purchaser of the transactions contemplated hereby have been duly authorized by all necessary action on the part of the Purchaser and no further action is required by the Purchaser, its board of directors or its shareholders in connection herewith. This Agreement has been duly executed by the Purchaser and, when delivered in accordance with the terms hereof, will constitute the valid and binding obligation of the Purchaser enforceable against the Purchaser in accordance with its terms except (i) as limited by general equitable principles and applicable bankruptcy, insolvency, reorganization, moratorium and other laws of general application affecting enforcement of creditors' rights generally, (ii) as limited by laws relating to the availability of specific performance, injunctive relief or other equitable remedies and (iii) insofar as indemnification and contribution provisions may be limited by applicable law.

8.	Effect on Agreements
	Except as expressly amended hereby, all of the terms and conditions of the Agreements (as defined in the Purchase Agreement), as amended, shall remain in full force and effect after the execution of this Agreement.
9.	Amendments and Waivers
	The provisions of this Agreement, including the provisions of this sentence, may not be amended, modified or supplemented, and waivers or consents to departures from the provisions hereof may not be given, unless the same shall be in writing and signed by the Company, the Issuer and the Purchaser.
10.	Notices
	Any and all notices or other communications or deliveries required or permitted to be provided hereunder shall be delivered as set forth in the applicable Agreement (as defined in the Purchase Agreement).
11.	Successors and Assigns
	This Agreement may not be assigned by any party with the prior written consent of the other parties. The terms and conditions of this Agreement shall inure to the benefit of and be binding upon the respective permitted successors and assigns of the parties. Nothing in this Agreement, express or implied, is intended to confer upon any party other than the parties hereto or their respective successors and assigns any rights, remedies, obligations, or liabilities under or by reason of this Agreement, except as expressly provided in this Agreement.
12.	Execution and Counterparts
	This Agreement may be executed in two or more counterparts, all of which when taken together shall be considered one and the same agreement. In the event that any signature is delivered by facsimile transmission or by e-mail delivery of a ".pdf" format data file, such signature shall create a valid and binding obligation of the party executing (or on whose behalf such signature is executed) with the same force and effect as if such facsimile or ".pdf" signature page were an original thereof.
13.	Expenses

	The Issuer and the Company shall promptly reimburse the Purchaser, upon first written demand, for all actual and out-of-pocket costs and expenses incurred by the Purchaser in respect of (a) the negotiation, execution and delivery of the term sheet relating to this Agreement, this Agreement and any and all related agreements and documents, and (b) the enforcement of any right or remedy by the Purchaser against the Issuer and/or the Company under or in respect of the term sheet relating to this Agreement, this Agreement and any and all related agreements and documents.
14.	Further Assurances
	The parties shall execute and deliver all such further instruments and documents and take all such other actions as may reasonably be required to carry out the transactions contemplated hereby and to evidence the fulfillment of the agreements herein contained.
15.	Governing Law
	This Agreement shall be governed by, and construed in accordance with, the laws of the State of New York without regard to the principles of conflicts of law thereof that would defer to the substantive laws of another jurisdiction.
16.	Severability
	If one or more provisions of this Agreement are held to be unenforceable under Applicable Law, such provision shall be excluded from this Agreement and the balance of this Agreement shall be interpreted as if such provision were so excluded and shall be enforceable in accordance with its terms.
17.	Headings
	The headings in this Agreement are for convenience only, do not constitute a part of the Agreement and shall not be deemed to limit or affect any of the provisions hereof.

[signature page follows]

            IN WITNESS WHEREOF, the parties have duly executed this Agreement as of the date first written above.

POLYMET MINING CORP.

By:	/s/ Douglas Newby
	Name: Douglas Newby
	Title: Chief Financial Officer

POLY MET MINING, INC.

By:	/s/ Douglas Newby
	Name: Douglas Newby
	Title: Chief Financial Officer

GLENCORE AG

By:	/s/ A. Hubmann
	/s/ M. Haering
	Name: A. Hubmann and M. Haering
	Title: Directors

EX-99.53

Exhibit 99.53 

EX-99.54

Exhibit 99.54

EX-99.55

Exhibit 99.55