UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D/A

Under the Securities Exchange Act of 1934

(Amendment No. 11)*

(Name of Issuer)

(Title of class of securities)

(CUSIP Number)

(Name, Address and Telephone Number of Person Authorised to Receive Notices and Communications)

(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 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).

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Item 1. Security and Issuer

This Amendment No. 11 to Schedule 13D amends and supplements the statement on Schedule 13D originally filed by Rio Tinto plc (“Rio Tinto”) and Rio Tinto International Holdings Limited (“RTIH”) on November 3, 2006, and amended on September 12, 2007, October 26, 2007, January 7, 2008, April 10, 2008, October 30, 2009, March 4, 2010, July 7, 2010, September 13, 2010, December 14, 2010, and February 4, 2011 (as amended and supplemented, the “Schedule 13D”) with the Securities and Exchange Commission (the “SEC”), relating to the common shares, without par value (the “Shares”), of Ivanhoe Mines Ltd., a corporation continued under the laws of the Yukon Territory, Canada (the “Company”).

Item 3. Source and Amount of Funds or Other Consideration

Item 3 of the Schedule 13D is amended and supplemented as follows:

On June 21, 2011, Rio Tinto gave notice to the Company that it is exercising its remaining Series B Warrants, Series C Warrants and Type B, Series 1 Warrants (collectively, the “Warrants”). Under the December 2010 Heads of Agreement, Rio Tinto agreed to exercise its remaining Warrants for the ongoing development of the Oyu Tolgoi project by no later than January 2012.

The remaining Warrants entitled Rio Tinto to acquire 55,122,253 Shares at an average subscription price of approximately US$9.10 per share, for total consideration of approximately US$502 million.

The funds for the exercise of the remaining Warrants were obtained by RTIH from the working capital of Rio Tinto.

Item 5. Interest in Securities of the Issuer

Item 5 of the Schedule 13D is hereby amended and supplemented as follows:

The responses of Rio Tinto and RTIH to Rows (11) through (13) of the cover pages of this Schedule 13D and the information set forth in Item 3 are hereby incorporated by reference in this Item 5.

Pursuant to the exercise of the remaining Series B Warrants, Series C Warrants and Type B, Series 1 Warrants RTIH will acquire 55,122,253 Shares at an average subscription price of approximately US$9.10 per share.

Therefore, each of Rio Tinto and RTIH is deemed to beneficially own 357,819,864 Shares which, assuming the exercise of the Subscription Right, and the 55,122,253 Shares which will be acquired from the exercise of the remaining Series B Warrants, Series C Warrants and Type B, Series 1 Warrants, would represent 48.5 per cent of the Company’s outstanding Shares on a fully diluted basis.

The percentage of the class of securities identified pursuant to Item 1 beneficially owned by each of Rio Tinto and RTIH is based on 653,746,447 Shares, as contained in the Company’s Quarterly Financial Report for the Three Months Ended March 31, 2011.

In addition, the Shares deemed beneficially owned by each of Rio Tinto and RTIH with respect to which such person (i) has sole voting power, (ii) shares voting power, (iii) has sole dispositive power and (iv) shares dispositive power are listed in the responses to Items 7, 8, 9 and 10, respectively, of the cover page of this Schedule 13D relating to such person.

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Except as disclosed in this Schedule 13D, neither Rio Tinto nor RTIH nor, to the best of their knowledge, any of the persons listed in Schedule A hereto, beneficially owns any Shares or has the right to acquire any Shares.

Except as disclosed in this Schedule 13D, neither Rio Tinto nor RTIH nor, to the best of their knowledge, any of the persons listed in Schedule A hereto, presently has the power to vote or to direct the vote or to dispose or direct the disposition of any of the Shares which they may be deemed to beneficially own.

Except as disclosed in this Schedule 13D, neither Rio Tinto nor RTIH nor, to the best of their knowledge, any of the persons listed in Schedule A hereto, has effected any transaction in the Shares during the past 60 days.

To the best knowledge of Rio Tinto and RTIH, no other person has the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the Shares beneficially owned by Rio Tinto and RTIH.

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

Item 6 of the Schedule 13D is hereby amended and supplemented as follows:

Following the exercise of the remaining Warrants, Rio Tinto’s increased ownership will permit it to nominate an additional director to Ivanhoe’s board which will increase Rio Tinto-nominated directors from six to seven out of a total of 14.

On June 8, 2011, RTIH entered into an agreement with the Government of Mongolia which evidences the commitment made and disclosed in the amendment to this Schedule 13D filed with the SEC on December 14, 2010. The description of this agreement contained herein is qualified in its entirety by reference to Exhibit J attached hereto, which is incorporated by reference herein.

Item 7. Materials to be Filed as Exhibits

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SIGNATURES

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

Dated: June 28, 2011

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SCHEDULE A

The response set forth in Schedule A of the Schedule 13D is hereby amended and restated in its entirety with the information below:

Rio Tinto plc

Directors and Executive Officers

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EXHIBIT INDEX

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Exhibit A

JOINT FILING AGREEMENT

The undersigned hereby agree that the Statement on Schedule 13D, dated November 3, 2006, with respect to the common shares, without par value, of Ivanhoe Mines Ltd. is, and any amendments thereto executed by each of us shall be, filed on behalf of each of us pursuant to and in accordance with the provisions of Rule 13d-1(k)(1) under the Securities and Exchange Act of 1934, as amended, and that this Agreement shall be included as an Exhibit to the Schedule 13D and each such amendment. Each of the undersigned agrees to be responsible for the timely filing of the Schedule 13D and any amendments thereto, and for the completeness and accuracy of the information concerning itself contained therein. This Agreement may be executed in any number of counterparts, all of which taken together shall constitute one and the same instrument.

IN WITNESS WHEREOF, the undersigned have executed this Agreement as of the 3rd day of November, 2006.

Exhibit J

PROSCRIBED PERSON’S AGREEMENT

This Agreement is made between The Government of Mongolia (the “GoM”), Ivanhoe Mines Ltd. (“Ivanhoe”) and Rio Tinto International Holdings Limited (“Rio Tinto”) this 8 day of June, 2011 in connection with the Investment Agreement dated October 6, 2009 (the “Investment Agreement”) between the GoM, Ivanhoe Mines Mongolia LLC (now known as Oyu Tolgoi LLC) (“OT LLC”), Ivanhoe and Rio Tinto.

WHEREAS OT LLC is the owner of the Mining Licenses relating to, and is carrying out, the OT Project;

AND WHEREAS Ivanhoe and the GoM own, through their wholly owned subsidiaries, 66% and 34%, respectively, of the outstanding shares of OT LLC;

AND WHEREAS Rio Tinto is the largest shareholder of Ivanhoe and is intended by the GoM and Ivanhoe to be appointed to manage the OT Project;

AND WHEREAS Ivanhoe and Rio Tinto recognize and respect the rights and interests of the GoM in the OT Project, both as a sovereign state and a partner in the OT Project, and its concerns relating to the potential holding by a Proscribed Person of any shares of OT LLC or another subsidiary of Ivanhoe that is a direct or indirect shareholder of OT LLC.

NOW, THEREFORE, for good and valuable consideration, the sufficiency and receipt whereof are hereby acknowledged, the undersigned hereby agree as follows:

1. All capitalized terms and expressions contained herein shall have the meanings ascribed thereto in the Investment Agreement unless the context otherwise requires.

2. Ivanhoe hereby agrees that it will not, and will cause its Affiliates (other than members of the Rio Tinto Group) to not sell or transfer to a Proscribed Person any shares they may from time to time hold in OT LLC or another subsidiary of Ivanhoe that is a direct or indirect shareholder of OT LLC without prior consultation with and the written consent of the GoM.

3. Rio Tinto hereby agrees that it will not, and will cause its Affiliates (other than members of the Ivanhoe Group) to not, sell or transfer to a Proscribed Person any shares they may from time to time hold in Ivanhoe, OT LLC or another subsidiary of Ivanhoe that is a direct or indirect shareholder of OT LLC without prior consultation with and the written consent of the GoM.

4. The GoM hereby agrees that it will not, and will cause its Affiliates to not sell or transfer to a Proscribed Person (other than one if its Affiliates in accordance with the Shareholders’ Agreement) any shares they may from time to time hold in OT LLC without prior consultation with and the approval of Ivanhoe and Rio Tinto.

5. The provisions of Chapter 14 (Dispute Resolution) of the Investment Agreement shall apply to this Agreement with necessary changes.

6. This Agreement is legally binding on the parties and shall be governed by and interpreted in accordance with the laws of Mongolia and international treaties to which Mongolia is a party.

7. This Agreement supersedes all previous agreements and understandings between the parties in relation to the matters regulated by this Agreement.

8. Each party warrants to the other parties that it has full power and lawful authority to execute and deliver this Agreement and to perform its obligations hereunder.

9. This Agreement will be provided and executed in the Mongolian and English languages, with each party retaining one copy of both documents in each language and the parties agree that the Mongolian and English versions will be treated equally except that, in the event of any legal dispute in the interpretation between the two-language versions, the English version shall prevail for both documents.

IN WITNESS WHEREOF this Agreement has been signed by the duly authorized representatives of the parties as of the date first written above.