When we issue common stock under the registration statement we may provide a prospectus supplement that will contain specific information about the terms of that offering. The prospectus supplement may also impair US Gold's business operationsadd, update or adversely affectchange information contained in this prospectus. You should read both this prospectus and any prospectus supplement together with additional information described under the holders of the exchangeable shares who participate in the exchange offering.heading "Where You Can Find More Information."

USE OF PROCEEDS

Holders of exchangeable shares        We will experience a delay in receiving shares of US Goldbe offering and issuing our common stock from the date they request an exchange, which may affect the valuetime to time in connection with acquisitions of the shares the holder receivesbusinesses, assets, properties or securities. Unless otherwise indicated in an exchange.

        Holders of exchangeable shares who requestany prospectus supplement, we do not expect to receive US Gold common stock in exchange for their exchangeable shares will not receive US Gold common stock until approximately five business days after the applicable request is received. During this period, the market price of US Gold common stock may increase or decrease. Any such increase or decrease would affect the value of the consideration to be received by such a holder of exchangeable shares upon a subsequent sale of the US Gold common stock received in the exchange.

The exchange of your exchangeable shares is generally taxable in Canada.

        Based on the tax laws as of the date of this prospectus, the exchange of exchangeable shares for shares of US Gold common stock is generally a taxable event in Canada. A holder's tax consequences can vary depending on a number of factors, including the residency of the holder, the method of the exchange and the length of time that the exchangeable shares were held prior to the exchange. Canadian income tax consequences will vary depending on your particular circumstances. See "Material Canadian Federal Income Tax Consequences" for a summary of certain material Canadian federal income tax consequences relating to the exchangeable shares. We strongly urge you to consult your tax advisor as to the tax consequences of exchanging your exchangeable shares for US Gold common stock.

The exchange of your exchangeable shares may be taxable in the U.S.

        The U.S. federal income tax consequences of an exchange of exchangeable shares for shares of US Gold depend on whether the exchangeable shares are treated for U.S. federal income tax purposes as shares of Canadian Exchange Co. or as shares of US Gold common stock. There is no direct authority under existing United States federal income tax law concerning whether the exchangeable shares should be treated as shares of Canadian Exchange Co. or shares of US Gold common stock. Neither Minera Andes, US Gold nor Canadian Exchange Co. has requested, or intends to request, a rulingany cash proceeds from the Internal Revenue Service or an opinion of counsel regarding the status of the exchangeable shares for United States federal income tax purposes. The discussion under the heading "Material United States Federal Income Tax Consequences" includes a discussion of the alternative United States federal income tax consequences of the exchange of exchangeable shares depending on whether the exchangeable shares are treated as either (i) shares of US Gold common stock or (ii) shares of Canadian Exchange Co. Generally, for United States federal income tax purposes, a U.S. Holder's (and in certain circumstances a Non-U.S. Holder's) exchange of exchangeable shares for shares of US Gold common stock will be a taxable sale in which the holder will recognize gain or loss if the exchangeable shares are treated as shares of Canadian Exchange Co. and not as shares of US Gold common stock. Holders of exchangeable shares should consider that the United States federal income tax consequences of an exchange of exchangeable shares may be adverse to the holder based on the holder's particular circumstances. Holders should take into account the possibility that the Internal Revenue Service may assert and prevail with a position on the status of the exchangeable shares that is contrary to the position taken by the holder.these offerings.

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COMPARATIVE MARKET PRICE AND DIVIDEND INFORMATIONDESCRIPTION OF COMMON STOCK

        The table below sets forth the closing sale price of US Gold common stock as reported on the NYSE on June 13, 2011, the last trading day prior to the public announcement of the Arrangement, and on December 1, 2011, the most recent practicable trading day prior to the date of this prospectus. The exchangeable shares are not currently listed for trading on any exchange and had no established market price as of June 13, 2011 and December 1, 2011. However, the TSX has conditionally approved the listing of the exchangeable shares, to be listed the trading symbol "MAQ" once the Arrangement is completed.

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THE EXCHANGE OFFER

The Exchange Offer

        The purpose of the exchange offer is to exchange any and all outstanding exchangeable shares for shares of US Gold common stock, so that following completion of the exchange offer all of the holders of exchangeable shares shall have received shares of US Gold common stock.

        We are filing this registration statement on Form S-4, of which this prospectus is a part, with the SEC in order to register under the Securities Act the issuance from time to time of shares of our common stock upon exchange of the exchangeable shares. Each exchangeable share is substantially the economic and voting equivalent of a share of US Gold common stock and is exchangeable on a one-for-one basis for a share of US Gold common stock at any time, at the option of the holder. Any exchangeable shares not previously exchanged will, upon the direction of Canadian Exchange Co.'s board of directors, be redeemed for shares of US Gold common stock on any date that is on or after the tenth year anniversary of the date on which exchangeable shares are first issued, subject to applicable law and the due exercise by either us or Callco of our or its redemption call right, unless Canadian Exchange Co. redeems them earlier upon the occurrence of certain events.

Terms of the Exchange Offer

        US Gold is offering, upon the terms and subject to the conditions described in this prospectus, to exchange shares of US Gold common stock for the outstanding exchangeable shares of Canadian Exchange Co. A description of how a holder may exchange the exchangeable shares, and of US Gold's or Callco's redemption rights, is provided below in the section entitled "Description of Capital Stock of US Gold—Exchangeable Shares". The rights of the holders of exchangeable shares, including exchange rights, are described in greater detail in the Plan of Arrangement which is included as Exhibit 2.1 to the registration statement, of which this prospectus is a part.

Withholding Rights

        Each of US Gold, Callco, Canadian Exchange Co. and Canadian Exchange Co.'s transfer agent will be entitled to deduct and withhold from any consideration otherwise payable to any holder of exchangeable shares such amounts as each of US Gold, Callco, Canadian Exchange Co. or Canadian Exchange Co.'s transfer agent is required to deduct and withhold with respect to such payment under theIncome Tax Act (Canada), the Code or any provision of federal, provincial, state, territorial, local or foreign tax law.

        To the extent that amounts are so withheld, such withheld amounts will be treated for all purposes as having been paid to the holder of the exchangeable shares in respect of which the deduction and withholding was made, provided, that the withheld amounts are actually remitted to the appropriate taxing authority. To the extent that the amount required to be deducted or withheld from any payment to a holder exceeds the cash portion of the consideration otherwise payable to the holder, US Gold, Callco, Canadian Exchange Co. and Canadian Exchange Co.'s transfer agent are authorized to sell or otherwise dispose of the portion of the consideration necessaryissue up to provide sufficient funds to US Gold, Callco, Canadian Exchange Co. or, Canadian Exchange Co.'s transfer agent, as the case may be, to enable it to comply with the deduction or withholding requirement and US Gold, Callco, Canadian Exchange Co. or Canadian Exchange Co.'s transfer agent, as the case may be, will notify the holder and remit to the holder any unapplied balance of the net proceeds of such sale.

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ACCOUNTING TREATMENT OF THE EXCHANGE

        The exchangeable shares are currently accounted for as outstanding capital stock of Canadian Exchange Co. The value of the shares of common stock of US Gold to be issued upon exchange are included in the outstanding capital stock. Accordingly, each issued and outstanding exchangeable share is treated as an issued and outstanding US Gold common share for purposes of calculating earnings per common share for US Gold.

USE OF PROCEEDS

        Because the shares of our common stock offered by this prospectus will be issued only in exchange for the exchangeable shares, we will not receive any cash proceeds from this offering.

PLAN OF DISTRIBUTION

        The shares of US Gold common stock offered in this prospectus will be issued in exchange for exchangeable shares as described in the terms of our Plan of Arrangement with Minera Andes, which is included as Exhibit A to the Arrangement Agreement which is included as Exhibit 2.1 to the registration statement of which this prospectus is a part. No broker, dealer or underwriter has been engaged in connection with this offering.

MATERIAL CONTRACTS BETWEEN US GOLD AND CANADIAN EXCHANGE CO.

        In connection with and concurrently with the closing of the Arrangement, US Gold and Canadian Exchange Co. are entering into the Voting and Exchange Trust Agreement among US Gold Corporation, Callco, Canadian Exchange Co. and Computershare Trust Company of Canada (the "Voting and Exchange Trust Agreement") and the Exchangeable Share Support Agreement among US Gold, Callco, and Canadian Exchange Co. (the "Support Agreement") solely for the purpose of ensuring that each exchangeable share is substantially the economic and voting equivalent of a share of US Gold common stock and is exchangeable on a one-for-one basis for a share of US Gold common stock at any time at the option of the holder or, in certain circumstances, by Canadian Exchange Co., US Gold or Callco. Together, the Voting and Exchange Trust Agreement and the Support Agreement set forth the terms governing the exchangeable shares. See the section entitled "Description of Capital Stock of US Gold—Exchangeable Shares" for more information. Through the Voting and Exchange Trust Agreement and the issuance by US Gold to the trustee of one share of Series B Special Voting Preferred Stock, each holder of an exchangeable share effectively has the ability to cast votes along with holders of US Gold common stock. In addition, the Voting and Exchange Trust Agreement grants exchange rights upon an event of insolvency of Canadian Exchange Co. or the liquidation, dissolution or winding up of US Gold. The Support Agreement provides that the exchangeable shares have the same dividend and distribution rights as US Gold common stock and any change to the rights, privileges or other terms of US Gold common stock will be simultaneously made to the exchangeable shares.

        This description of the Voting and Exchange Trust Agreement and the Support Agreement is qualified in its entirety by reference to such agreements, which are included as Exhibit 10.1 and Exhibit 10.2, respectively, to the registration statement of which this prospectus is a part and are incorporated herein by reference.

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MATERIAL DIFFERENCES BETWEEN THE RIGHTS OF HOLDERS OF US GOLD COMMON STOCK AND HOLDERS OF EXCHANGEABLE SHARES

        Holders of the exchangeable shares have essentially the same voting rights with respect to US Gold and the same economic interests as holders of US Gold common stock. While the rights and privileges of shareholders of an Alberta corporation are, in many instances, comparable to those of shareholders of a Colorado corporation, there are certain differences. These differences arise from differences between Alberta and Colorado law, and between the Canadian Exchange Co. articles of incorporation and bylaws and the US Gold articles of incorporation and bylaws. The following is a summary of some of the most significant differences in shareholder rights between Canadian Exchange Co. and US Gold. This summary is not intended to be complete and is qualified in its entirety by reference to the ABCA, the Colorado Act and the governing corporate instruments of Canadian Exchange Co. and US Gold.

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DESCRIPTION OF CAPITAL STOCK OF US GOLD

        Following shareholder approval at a special meeting in connection with the Arrangement, our authorized capital will consist of 500,000,000 shares of common stock, no par value, and 2 shares of preferred stock, no par value. As of , 2012,August 14, 2018, there were a total of 337,276,381 shares of our common stock and two shares of preferred stock, one designated as Series A Special Voting Preferred Stock (the "Series A Preferred Share") and the other designated Series B Special Voting Preferred Stock (the "Series B Preferred Share"), issued and outstanding.

        The following discussion summarizes the rights and privileges of our outstanding capital stock and certain securities that may be convertible into our capitalcommon stock and is qualified by reference to the relevant provisions of the laws of the State of Colorado law and US Gold'sour Amended and Restated Articles of Incorporation (the "US Gold Articles(our "Articles of Incorporation") and Bylaws which have been filed with the SEC and are included as Exhibits 3.1 and 3.2, respectively, toincorporated by reference into the registration statement of which this prospectus is a part and are incorporated herein by reference.

Common Stockpart.

        The holders of our common stock are entitled to one vote for each share held of record on all matters submitted to a vote of the shareholders, including the election of directors. Cumulative voting for directors is not permitted. Subject to preferences that may be applicable to any then outstanding preferred stock, holders of common stock are entitled to receive ratably those dividends, if any, as may be declared by our board of directors (the "Board") out of legally available funds. Upon our liquidation, dissolution or winding up, the holders of common stock will be entitled to share ratably in the net assets legally available for distribution to shareholders after the payment of all of our debts and other liabilities of our Company, subject to the prior rights of any preferred stock then outstanding. Holders of common stock have no preemptive or conversion rights or other subscription rights and there are no redemption or sinking funds provisions applicable to the common stock. The US Gold ArticlesThere are no restrictions on the alienability of Incorporationour common stock and there are no provisions discriminating against any existing or prospective holder of our Bylaws do not include any provisioncommon stock as a result of such holder owning a substantial amount of the Company's securities. We refer you to the "Anti-Takeover Provisions" subsection below for information regarding provisions that would delay, defer or prevent a change in control of our Company. However,

Anti-Takeover Provisions

        Our Articles of Incorporation and our Bylaws include certain provisions that could delay, defer or prevent a change in control of our Company. Among other things, our Articles of Incorporation and Bylaws:

•

provide that the authorized number of directors may be fixed from time to time by our Board of Directors; provided, however, that the authorized number of directors shall not be less than three nor more than nine;



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do not provide for cumulative voting rights (therefore allowing the holders of a majority of the shares of common stock entitled to vote in any election of directors to elect all of the directors standing for election, if they should so choose); and



•

provide that special meetings of our shareholders may be called only by our president, the chairman of the Board of Directors, the Board of Directors, or the holders of not less than 10% of all shares entitled to vote at the meeting.

        Moreover, pursuant to the laws of the State of Colorado, certain significant transactions would require the affirmative vote of a majority of the shares eligible to vote at a meeting of shareholders, which requirement could result in delays to or greater cost associated with a change in control of US Gold.McEwen Mining.

Preferred StockExchange Listings

        OfOur common stock is listed on the two shares of preferred stock authorizedNYSE and on the TSX, each under the US Gold Articles of Incorporation, one share is designated as Series A Preferred Shares and one share is designated as Series B Preferred Share, both of which are issued and outstanding. The US Gold Articles of Incorporation do not include authorization for an undesignated class or "blank check" preferred stock, and any issuance of preferred stock would require shareholder approval.

Series A Special Voting Preferred Stock

        The Series A Preferred Share was created by us and issued in connection with the acquisition of White Knight Resources Ltd., Nevada Pacific Gold Ltd. and Tone Resources Limited (the "Acquired Companies") in 2007 to facilitate the issuance of exchangeable shares (the "2007 Exchangeable Shares") of our wholly-owned indirect subsidiary, US Gold Canadian Acquisition Corporation ("2007 Acquisition Co.symbol "MUX."). The Series A Preferred Share is held by a trustee under a voting and exchange trust agreement and will be outstanding so long as any of the 2007 Exchangeable Shares are outstanding, excluding any shares owned by US Gold or its subsidiaries.

        The Series A Preferred Share entitles the holder thereof to an aggregate number of votes equal to the number of the 2007 Exchangeable Shares issued and outstanding from time to time and which are

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not owned by US Gold or its subsidiaries. As of                        , 2012, the Series A Preferred Share was entitled to                        votes, based upon                        2007 Exchangeable Shares outstanding on such date, which are not owned by US Gold or its subsidiaries. Except as otherwise provided herein or by law, the holder of the Series A Preferred Share, the holder of the Series B Preferred Share and the holders of our common stock vote together as one class on all matters submitted to a vote of our shareholders. The holder of the Series A Preferred Share have no special voting rights, and its consent is not required, except to the extent it is entitled to vote with the holders of shares of our common stock, for taking any corporate action.

        At such time as (a) the Series A Preferred Share entitles its holder to a number of votes equal to zero because there are no 2007 Exchangeable Shares issued and outstanding that are not owned by US Gold and its subsidiaries, and (b) there is no share of stock, debt, option or other agreement, obligation or commitment of 2007 Acquisition Co. which could by its terms require 2007 Acquisition Co. to issue any 2007 Exchangeable Shares to any person other than us, then the Series A Preferred Share will thereupon be retired and cancelled promptly thereafter.

        If the Series A Preferred Share should be purchased or otherwise acquired by us in any manner whatsoever, then such Series A Preferred Share will be retired and cancelled promptly after the acquisition thereof. Such Series A Preferred Share will upon its cancellation, and upon the taking of any action required by applicable law, become an authorized but unissued share of preferred stock and may be reissued as part of a new series of preferred stock to be created by resolution or resolutions of the Board, subject to the conditions and restrictions on issuance under applicable law or set forth in the US Gold Articles of Incorporation or US Gold's Bylaws.

        The holder of the Series A Preferred Share is not entitled to receive any portion of any dividend or distribution at any time. The Series A Preferred Share is not redeemable.

        Upon any liquidation, dissolution or winding up of US Gold, the holder of the Series A Preferred Share will not be entitled to any portion of any related distribution.

2007 Exchangeable Shares

        The 2007 Exchangeable Shares were issued by our subsidiary, 2007 Acquisition Co., in connection with the acquisition of the Acquired Companies. As of                        , 2012, there were approximately                        2007 Exchangeable Shares outstanding that were not held by US Gold or its subsidiaries. The 2007 Exchangeable Shares are exchangeable on a one-for-one basis at any time at the option of the holder of the 2007 Exchangeable Shares into shares of our common stock.

Retraction of Exchangeable Shares by Holders

        Subject to the retraction call right described below and applicable law, holders of the 2007 Exchangeable Shares will be entitled at any time to retract (i.e., to require 2007 Acquisition Co. to redeem) any or all 2007 Exchangeable Shares held by them and to receive the retraction price per 2007 Exchangeable Share to be satisfied by issuance of one share of common stock of US Gold, plus the dividend amount, which is the full amount of all declared and unpaid dividends on the 2007 Exchangeable Shares and all dividends and distributions declared on a share of common stock of US Gold that have not yet been declared on the 2007 Exchangeable Shares. Holders of the 2007 Exchangeable Shares may effect a retraction by presenting to 2007 Acquisition Co. or its transfer agent the certificate(s) representing the 2007 Exchangeable Shares the holder desires to have 2007 Acquisition Co. redeem, together with such other documents and instruments as may be required under the ABCA, the Articles of Incorporation of 2007 Acquisition Co. or by its transfer agent, and a duly executed retraction request specifying that the holder desires to have the number of retracted shares specified therein redeemed by 2007 Acquisition Co.

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        A holder of retracted shares may withdraw its retraction request, by written notice to 2007 Acquisition Co., before the close of business on the business day immediately preceding the retraction date, in which case the retraction request will be null and void and the revocable offer will be deemed to have been revoked.

        If, as a result of solvency provisions of applicable law, 2007 Acquisition Co. is not permitted to redeem all 2007 Exchangeable Shares tendered by a retracting holder and neither we nor U.S. Gold Alberta ULC, our wholly-owned indirect subsidiary ("Alberta ULC") has exercised its retraction call right, 2007 Acquisition Co. will redeem up to the maximum permissible number of the 2007 Exchangeable Shares tendered by the holder. US Gold or Alberta ULC will be required to purchase any 2007 Exchangeable Shares not redeemed by 2007 Acquisition Co. in exchange for shares of our common stock on the retraction date under the optional exchange right described below.

Distribution on Liquidation of 2007 Acquisition Co.

        Subject to applicable law, in the event of the liquidation, dissolution or winding up of 2007 Acquisition Co. or any other distribution of its assets among its shareholders for the purpose of winding up its affairs, holders of the 2007 Exchangeable Shares are entitled, subject to applicable law, to receive from the assets of 2007 Acquisition��Co., a liquidation payment that will be satisfied by the issuance of one share of our common stock plus the dividend amount, if any, for each 2007 Exchangeable Share. This liquidation amount will be paid to the holders of the 2007 Exchangeable Shares before any distribution of assets of 2007 Acquisition Co. is made to the holders of the common shares or any other shares of 2007 Acquisition Co. ranking junior to the 2007 Exchangeable Shares, and is subject to the exercise by US Gold or Alberta ULC of its liquidation call right described in the section entitled "—Liquidation Call Right" below.

Automatic Exchange Upon Liquidation of US Gold

        In the event of US Gold's liquidation, all of the then outstanding 2007 Exchangeable Shares will be automatically exchanged for shares of US Gold common stock. To effect an automatic exchange, US Gold, or at US Gold's option, Alberta ULC, will purchase all of the 2007 Exchangeable Shares from the holders on the fifth business day prior to the effective date of a liquidation. The purchase price payable for each 2007 Exchangeable Share purchased in a liquidation of US Gold will be satisfied by the issuance of one share of US Gold common stock plus the dividend amount, if any.

Redemption of 2007 Exchangeable Shares by 2007 Acquisition Co.

        Subject to applicable law and the due exercise by either US Gold or Alberta ULC of its redemption call right, 2007 Acquisition Co. will redeem all of the then outstanding 2007 Exchangeable Shares on the date, if any, established by the board of directors of 2007 Acquisition Co., which date may not be before the earlier of: (a) March 28, 2014; and (b) any date established by the board of directors of 2007 Acquisition Co. for the redemption of the 2007 Exchangeable Shares at such time as there are fewer than 4,296,883 2007 Exchangeable Shares outstanding. The redemption price per 2007 Exchangeable Share will be satisfied by delivering to the holder one share of US Gold common stock plus the dividend amount, if any.

Retraction Call Right

        Each of US Gold and Alberta ULC has an overriding retraction call right to acquire all but not less than all of the 2007 Exchangeable Shares that a holder of the 2007 Exchangeable Shares requests 2007 Acquisition Co. to redeem. The purchase price payable for each 2007 Exchangeable Share will be satisfied by delivering to the holder one share of US Gold common stock plus the dividend amount, if any.

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Liquidation Call RightTransfer Agent

        Each of US Gold and Alberta ULC has an overriding liquidation call right, in the event of and notwithstanding a proposed liquidation, dissolution or winding up of 2007 Acquisition Co., to acquire all but not less than all of the 2007 Exchangeable Shares then outstanding. The purchase price payable for each 2007 Exchangeable Share will be satisfied by delivering to the holder one share of US Gold common stock plus the dividend amount, if any. Upon the exercise by US Gold or Alberta ULC of the liquidation call right, the holders will be obligated to transfer their 2007 Exchangeable Shares to US Gold or Alberta ULC, as applicable. The acquisition by US Gold or Alberta ULC of all of the outstanding 2007 Exchangeable Shares upon the exercise of the liquidation call right will occur on the effective date of the voluntary or involuntary liquidation, dissolution or winding up of 2007 Acquisition Co.

Redemption Call Right

        Each of US Gold and Alberta ULC has an overriding redemption call right, notwithstanding the proposed automatic redemption of the 2007 Exchangeable Shares by 2007 Acquisition Co. in the share provisions, to acquire all but not less than all of the 2007 Exchangeable Shares then outstanding. The purchase price payable for each 2007 Exchangeable Share will be satisfied by delivering to the holder one share of US Gold common stock plus the dividend amount, if any. Upon the exercise by US Gold or Alberta ULC of the redemption call right, the holders will be obligated to transfer their 2007 Exchangeable Shares to US Gold or Alberta ULC, as applicable.

        If US Gold or Alberta ULC exercises one or more of its call rights, shares of US Gold common stock will be directly issued to holders of the 2007 Exchangeable Shares and US Gold or Alberta ULC, as applicable, will become the holder of the 2007 Exchangeable Shares. US Gold and Alberta ULC will not be entitled to exercise any voting rights attached to the 2007 Exchangeable Shares that are acquired from the holders.

Voting Rights

        Under the voting and exchange trust agreement US Gold has entered into with 2007 Acquisition Co. and        Computershare Trust Company, of Canada, holders of the 2007 Exchangeable Shares will be entitled to receive notice of and attend any meeting of US Gold shareholders and to vote at any such meetings.

Dividends

        Holders of the 2007 Exchangeable Shares will be entitled to receive dividends equivalent to the dividends, if any, paid from time to time by US Gold on shares of its common stock. The declaration date, record date and payment date for dividends on the 2007 Exchangeable Shares will be the same as that for any corresponding dividends on shares of US Gold common stock.

Amendment and Approval

        Any approval required to be given by the holders of the 2007 Exchangeable Shares to add to, change or remove any right, privilege, restriction or condition attaching to the 2007 Exchangeable Shares or any other matter requiring the approval or consent of the holders of the 2007 Exchangeable Shares in accordance with applicable law will be deemed to have been sufficiently given if it has been given in accordance with applicable law, subject to a minimum requirement that such approval be evidenced by a resolution passed by not less than "66²/3%" of the votes cast on such resolution at a meeting of holders of the 2007 Exchangeable Shares duly called and held, excluding the 2007 Exchangeable Shares beneficially owned by US Gold or its subsidiaries.

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Series B Special Voting Preferred Stock

        The Series B Preferred Share was created by us and issued in connection with the Arrangement to facilitate the issuance of the exchangeable shares of Canadian Exchange Co. The Series B Preferred ShareN.A. is held by a trustee under the Voting and Exchange Trust Agreement and will be outstanding so long as any of the exchangeable shares are outstanding, excluding any shares owned by US Gold or its subsidiaries.

        The Series B Preferred Share entitles the holder thereof to an aggregate number of votes equal to the number of the exchangeable shares issued and outstanding from time to time and which are not owned by US Gold or its subsidiaries. As of the date on which the exchangeable shares are issued in the Arrangement, the Series B Preferred Share will be entitled to 127,326,984 votes, based upon 127,326,984 exchangeable shares outstanding on such date, which are not owned by US Gold or its subsidiaries. Except as otherwise provided herein or by law, the holder of the Series B Preferred Share, the holder of the Series A Preferred Share and the holders of our common stock vote together as one class on all matters submitted to a vote of our shareholders. The holder of the Series B Preferred Share have no special voting rights, and its consent is not required, except to the extent it is entitled to vote with the holders of shares of our common stock, for taking any corporate action.

        At such time as (a) the Series B Preferred Share entitles its holder to a number of votes equal to zero because there are no exchangeable shares issued and outstanding that are not owned by US Gold and its subsidiaries, and (b) there is no share of stock, debt, option or other agreement, obligation or commitment of Canadian Exchange Co. which could by its terms require Canadian Exchange Co. to issue any exchangeable shares to any person other than us, then the Series B Preferred Share will thereupon be retired and cancelled promptly thereafter. Such Series B Preferred Share will upon its cancellation, and upon the taking of any action required by applicable law, become an authorized but unissued share of preferred stock and may be reissued as part of a new series of preferred stock to be created by resolution or resolutions of the Board, subject to the conditions and restrictions on issuance under applicable law or set forth in the US Gold Articles of Incorporation or US Gold's Bylaws.

        If the Series B Preferred Share should be purchased or otherwise acquired by us in any manner whatsoever, then such Series B Preferred Share will be retired and cancelled promptly after the acquisition thereof. Such share will upon its cancellation, and upon the taking of any action required by applicable law, become an authorized but unissued share of preferred stock and may be reissued as part of a new series of preferred stock to be created by resolution or resolutions of the Board, subject to the conditions and restrictions on issuance under applicable law or set forth in the US Gold Articles of Incorporation or US Gold's Bylaws.

        The holder of the Series B Preferred Share is not entitled to receive any portion of any dividend or distribution at any time. The Series B Preferred Share is not redeemable.

        Upon any liquidation, dissolution or winding up of US Gold, the holder of the Series B Preferred Share will not be entitled to any portion of any related distribution.

Exchangeable Shares

        The exchangeable shares were issued by our subsidiary, Canadian Exchange Co., in connection with the Arrangement. As of the date on which the exchangeable shares are issued in the Arrangement, there will be approximately 127,326,984 exchangeable shares outstanding that were not held by US Gold or its subsidiaries. The exchangeable shares are exchangeable on a one-for-one basis at any time at the option of the holder of the exchangeable shares into shares of US Gold common stock. The following is a summary description of the material provisions of the rights, privileges, restrictions and conditions attaching to the exchangeable shares.

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Retraction of Exchangeable Shares by Holders

        Subject to applicable law and the due exercise by either us or Callco of our or its retraction call right, holders of the exchangeable shares will be entitled at any time to retract (i.e., to require Canadian Exchange Co. to redeem) any or all exchangeable shares held by them and to receive in exchange for each exchangeable share, one share of common stock of US Gold, plus the dividend amount, which is equal to any cash dividends declared and payable but not yet paid on the exchangeable shares, any dividends declared and payable or paid on shares of our common stock that have not yet been declared or paid on the exchangeable shares and an amount representing the value of any non-cash dividends declared and payable but not yet paid on the exchangeable shares. Holders of exchangeable shares may effect a retraction by presenting to Canadian Exchange Co. or its transfer agent the certificate(s) representing the exchangeable shares the holder desires to be redeemed by Canadian Exchange Co. or the equivalent thereof, if any, together with such other documents and instruments as may be required under the ABCA, the Articles of Incorporation of Canadian Exchange Co. or by its transfer agent, and a duly executed retraction request specifying that the holder desires to have the number of retracted shares specified therein redeemed by Canadian Exchange Co. A holder of retracted shares may withdraw its retraction request, by written notice to Canadian Exchange Co., before the close of business on the business day immediately preceding the retraction date, in which case the retraction request will be null and void and the revocable offer constituted by the retraction request will be deemed to have been revoked.

        Upon receipt by Canadian Exchange Co. or its transfer agent of a retraction request and certificate(s) representing the exchangeable shares to be redeemed or the equivalent thereof, if any, Canadian Exchange Co. will immediately provide notice of such request to us and Callco. Instead of Canadian Exchange Co. redeeming the retracted shares, and provided that the retraction request is not revoked by the holder of exchangeable shares, we will have the right to purchase, and to the extent the right is not exercised by us, Callco will have the right to purchase, all but not less than all of the shares covered by the retraction request, which we refer to as our retraction call right. See the section entitled "Retraction Call Right" below.

        If, as a result of solvency requirement provisions or other provisions of applicable law, Canadian Exchange Co. is not permitted to redeem all exchangeable shares tendered by a retracting holder and neither we nor Callco has exercised its retraction call right, Canadian Exchange Co. will redeem up to the maximum permissible number of exchangeable shares tendered by the holder. We or Callco will be required to purchase any exchangeable shares not redeemed by Canadian Exchange Co. in exchange for shares of our common stock on the retraction date under the optional exchange right described below.

Distribution on Liquidation of Canadian Exchange Co.

        Subject to applicable law and the exercise by either us or Callco of our or its liquidation call right, in the event of the liquidation, dissolution or winding up of Canadian Exchange Co. or any other distribution of its assets among its shareholders for the purpose of winding up its affairs, holders of exchangeable shares shall be entitled to receive from the assets of Canadian Exchange Co. a liquidation payment that will be satisfied by the issuance of one share of our common stock plus the dividend amount, if any, for each outstanding exchangeable share. This liquidation amount will be paid to the holders of exchangeable shares before any distribution of assets of Canadian Exchange Co. is made to the holders of the common shares or any other shares of Canadian Exchange Co. ranking junior to the exchangeable shares and is subject to the exercise by us or Callco of our or its liquidation call right described in the section entitled "—Liquidation Call Right" below.

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Automatic Exchange Upon Liquidation of US Gold

        Under the Voting and Exchange Trust Agreement, in the event of our liquidation, all of the then outstanding exchangeable shares will be automatically exchanged for shares of our common stock. To effect an automatic exchange, we will purchase all of the exchangeable shares from the holders on the last business day prior to the effective date of a liquidation. The purchase price payable for each exchangeable share purchased in a liquidation of US Gold will be satisfied by the issuance of one share of our common stock plus the dividend amount, if any.

Redemption of Exchangeable Shares by Canadian Exchange Co.

        Subject to applicable law and the due exercise by either us or Callco of our or its redemption call right, Canadian Exchange Co. will, on the redemption date, redeem all of the then outstanding exchangeable shares for a purchase price equal to one share of our common stock for each outstanding exchangeable share plus the dividend amount, if any. The redemption date for the exchangeable shares will be the date, if any, established by the board of directors of Canadian Exchange Co. for the redemption by Canadian Exchange Co. of all but not less than all of the outstanding exchangeable shares, which date will be no earlier than the tenth anniversary of the effectiveness of the Arrangement, unless one of the conditions described in the paragraphs below is met.

        Subject to applicable law, and provided that neither we nor Callco have exercised the redemption call right, Canadian Exchange Co. will redeem all of the outstanding exchangeable shares upon at least 30 days prior notice to the holders of the exchangeable shares.

        The board of directors of Canadian Exchange Co. may accelerate the redemption date in the event that:

•

fewer than 5% of the total number of exchangeable shares issued in connection with the Arrangement (other than exchangeable shares held by us or our subsidiaries and subject to necessary adjustments to the number of shares to reflect permitted changes to exchangeable shares) are outstanding;



•

(i) any person, firm or corporation acquires directly or indirectly any voting security of US Gold and immediately after such acquisition, the acquirer has voting securities representing more than 50% of the total voting power of all the then outstanding voting securities of US Gold on a fully-diluted basis; (ii) the shareholders of US Gold approve a merger, consolidation, recapitalization or reorganization of US Gold, other than any such transaction which would result in the holders of outstanding voting securities of US Gold immediately prior to such transaction having more than 50% of the total voting power represented by the voting securities of the surviving entity outstanding immediately after such transaction; (iii) the shareholders of US Gold approve a liquidation of US Gold; or (iv) US Gold sells or disposes of all or substantially all of its assets, and, in each case, the board of directors of Canadian Exchange Co. determines that it is not reasonably practicable to substantially replicate the terms and conditions of the exchangeable shares in connection with such transaction and that the redemption of all but not less than all of the outstanding exchangeable shares is necessary to enable the completion of such transaction;



•

the holders of exchangeable shares are entitled to vote as shareholders of Canadian Exchange Co. on a certain matter, except with respect to the right to vote on general business matters presented at any annual meeting of Canadian Exchange Co. (including the election of one of the directors of Canadian Exchange Co.) and except with respect to the right to vote on any change to the rights of the holders of exchangeable shares where the approval of such change would be required to maintain the equivalence of the exchangeable shares with the shares of US Gold common stock, and to the extent that the board of directors of Canadian

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Exchange Co. has determined that it is not reasonably practicable to accomplish the business purpose intended by the matter on which the shareholders are entitled to vote, which business purpose must be bona fide and not for the primary purpose of causing the redemption date acceleration, in a commercially reasonable manner that does not result in such a vote; or

•

the holders of exchangeable shares are entitled to vote as shareholders of Canadian Exchange Co. on a proposed change to the rights of the holders of exchangeable shares where the approval of such change would be required to maintain the equivalence of the exchangeable shares with the shares of US Gold common stock and the holders of exchangeable shares fail to take the necessary action at a meeting or other vote of the holders of exchangeable shares, to approve or disapprove, as applicable, the matter.

Purchase for Cancellation

        Subject to applicable law and the Articles of Incorporation of Canadian Exchange Co., Canadian Exchange Co. may at any time purchase for cancellation all or any part of the outstanding exchangeable shares by private agreement with any holder of such exchangeable shares or by tender to all holders of record of the exchangeable shares or through the facilities of any stock exchange on which the exchangeable shares are listed or quoted at any price per share together with the dividend amount for which the record date has occurred prior to the date of purchase.

Call Rights

        As further described below, we and Callco will have certain overriding rights to acquire exchangeable shares from the holders. In each case, we have the initial call right and to the extent we do not exercise our right, Callco may exercise its right. A holder of exchangeable shares will be subject to different Canadian federal income tax consequences depending upon whether the call rights are exercised and by which entity and whether the relevant exchangeable shares are redeemed by Canadian Exchange Co. if the call rights are not exercised.

Change of Law Call Right

        Each of we and Callco have an overriding change of law call right to purchase (or to cause Callco to purchase) from all but not less than all of the holders of exchangeable shares (other than US Gold and its subsidiaries) all but not less than all of the exchangeable shares held by each such holder in the event of any amendment to theIncome Tax Act (Canada) and other applicable provincial income tax laws that permits holders of exchangeable shares who (a) are resident in Canada; (b) hold their exchangeable shares as capital property; and (c) deal at arm's length with us or Canadian Exchange Co., to exchange their exchangeable shares without requiring such holders to recognize any gain or loss or any actual or deemed dividend in respect of such exchange for the purposes of theIncome Tax Act (Canada) or applicable provincial income tax laws. The purchase price under the change of law call right is satisfied by delivering to the holder of exchangeable shares one share of our common stock for each exchangeable share purchased plus the dividend amount, if any. In the event of the exercise of the change of law call right by us or Callco, as the case may be, each holder of exchangeable shares shall be obligated to sell all the exchangeable shares held by such holder to us or Callco, as the case may be, on the change of law call date upon payment by us to such holder of the purchase price for each such exchangeable share. To exercise the change of law call right, we or Callco must notify the transfer agent of our or its intention to exercise such right at least 45 days before the date on which we or Callco intend to acquire the exchangeable shares. The transfer agent will notify the holders of exchangeable shares as to whether we or Callco have exercised the change of law call right forthwith after receiving notice from us or Callco.

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        Notwithstanding the foregoing, neither we nor Callco shall be entitled to exercise the change of law call right if more than 5% of the exchangeable shares are held by US residents.

Retraction Call Right

        Under the share provisions, each of we and Callco have an overriding retraction call right to acquire all but not less than all of the exchangeable shares that a holder of exchangeable shares requests Canadian Exchange Co. to redeem on the retraction date. Callco is only entitled to exercise its retraction call right with respect to those holders of exchangeable shares, if any, for which we have not exercised our retraction call right. The purchase price under the retraction call right is satisfied by delivering to the holder of exchangeable shares one share of our common stock for each exchangeable share purchased plus the dividend amount, if any.

        At the time of a retraction request by a holder of exchangeable shares, Canadian Exchange Co. will immediately notify us and Callco and either we or Callco must then advise Canadian Exchange Co. within five business days if we choose to exercise the retraction call right. If we or Callco do not advise Canadian Exchange Co. within the five-business day period, Canadian Exchange Co. will notify the holder as soon as possible thereafter that neither of us will exercise the retraction call right. Unless the holder revokes his or her retraction request, on the retraction date the exchangeable shares that the holder has requested Canadian Exchange Co. to redeem will be acquired by us or Callco (assuming either we or Callco exercise the retraction call right) or redeemed by Canadian Exchange Co., as the case may be, in each case for the retraction call purchase price as described in the preceding paragraph.

Liquidation Call Right

        Under the share provisions, each of we and Callco have an overriding liquidation call right, in the event of and notwithstanding a proposed liquidation, dissolution or winding up of Canadian Exchange Co., to acquire all but not less than all of the exchangeable shares then outstanding (other than exchangeable shares held by us or our subsidiaries). Callco is only entitled to exercise its liquidation call right with respect to those holders of exchangeable shares, if any, for which we have not exercised our liquidation call right. The purchase price under the liquidation call right is satisfied by delivering to the holder of exchangeable shares one share of our common stock for each exchangeable share purchased plus the dividend amount, if any. Upon the exercise by us or Callco of the liquidation call right, the holders will be obligated to transfer their exchangeable shares to us or Callco, as the case may be, for the purchase price described above. The acquisition by us or Callco of all of the outstanding exchangeable shares upon the exercise of the liquidation call right will occur on the effective date of the voluntary or involuntary liquidation, dissolution or winding up of Canadian Exchange Co.

        To exercise the liquidation call right, we or Callco must notify Canadian Exchange Co.'s transfer agent in writing, as agent for the holders of the exchangeable shares, the trustee and Canadian Exchange Co. of our or Callco's intention to exercise this right at least 30 days before the liquidation date in the case of a voluntary liquidation, dissolution or winding up of Canadian Exchange Co. and at least five business days before the liquidation date in the case of an involuntary liquidation, dissolution or winding up of Canadian Exchange Co. The transfer agent will notify the holders of exchangeable shares as to whether or not we or Callco have exercised the liquidation call right after the earlier of (a) the date notice of exercise has been provided to the transfer agent and (b) the expiry of the date by which the same may be exercised by us or Callco. If we or Callco exercise the liquidation call right on the liquidation date, we or Callco will purchase and the holders will sell all of the exchangeable shares for an amount equal to the liquidation call exercise price as described in the preceding paragraph.

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Redemption Call Right

        Under the share provisions, we and Callco have an overriding redemption call right, notwithstanding any proposed redemption of the exchangeable shares by Canadian Exchange Co., to acquire all but not less than all of the exchangeable shares then outstanding (other than exchangeable shares held by us or our subsidiaries). Callco is only entitled to exercise its redemption call right with respect to those holders of exchangeable shares, if any, for which we have not exercised our redemption call right. The purchase price under the redemption call right will be satisfied by delivering to the holder one share of our common stock plus the dividend amount, if any. In the event of the exercise of the redemption call right by us or Callco, as the case may be, each holder of exchangeable shares will be obligated to sell all their exchangeable shares to us or Callco, as the case may be, on the redemption date upon payment by us or Callco, as the case may be, to such holder of the purchase price for such exchangeable shares.

        To exercise the redemption call right, we or Callco must notify Canadian Exchange Co.'s transfer agent in writing, as agent for the holders of the exchangeable shares, and Canadian Exchange Co. of our or Callco's intention to exercise this right at least 30 days before the redemption date (other than in the case of an accelerated redemption date described above, in which case we or Callco, as the case may be, must notify the transfer agent and Canadian Exchange Co. on or before the redemption date). The transfer agent will notify the holders of exchangeable shares as to whether or not we or Callco exercised the redemption call right after the earlier of (a) the date notice of exercise has been provided to the transfer agent and (b) the expiry of the date by which the same may be exercised by us or Callco. If we or Callco exercise the redemption call right on the redemption date, we or Callco will purchase and the holders will sell all of the exchangeable shares for an amount equal to the redemption call purchase price as described in the preceding paragraph.

Effect of Call Rights Exercise

        If US Gold or Callco exercise one or more of its call rights, shares of our common stock will be directly issued to holders of exchangeable shares and we or Callco, as the case may be, will become the holder of the exchangeable shares. We or Callco will not be entitled to exercise any voting rights attached to the exchangeable shares that are acquired from the holders. If we or Callco decline to exercise the call rights when applicable, we will be required, under the Support Agreement, to issue shares of our common stock to the holders of exchangeable shares.

Voting Rights

        The number of directors of Canadian Exchange Co. will be fixed at three and the rights attaching to the exchangeable shares will entitle holders of exchangeable shares a limited right to vote on the election or appointment of one director but such holders will have no right to vote on the election of the remaining two directors. In addition, the holders of the exchangeable shares are entitled to receive notice of any meeting of the shareholders of Canadian Exchange Co. and to attend and vote thereat, except those meetings where only holders of a specified class or particular series of shares are entitled to vote, and each holder of exchangeable shares is entitled to one vote per exchangeable share in person or by proxy.

Ranking

        Holders of exchangeable shares will be entitled to a preference over holders of any common shares of Canadian Exchange Co. and any other shares ranking junior to the exchangeable shares with respect to the payment of dividends and the distribution of assets in the event of the liquidation, dissolution or winding up of Canadian Exchange Co., whether voluntary or involuntary, or any other distribution of the assets of Canadian Exchange Co. among its shareholders for the purpose of winding up its affairs.

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Dividends

        Holders of exchangeable shares will be entitled to receive dividends equivalent to the dividends, if any, paid from time to time by us on shares of our common stock. The declaration date, record dateprincipal office of Computershare Trust Company, N.A. is located at 250 Royall Street, Canton, MA 02021 and payment date for dividends on the exchangeable shares will be the same as that for any corresponding dividends on shares of our common stock.

Certain Restrictions

        Except with the approval of the holders of the exchangeable shares, Canadian Exchange Co. will not be permitted to:

•

pay any dividends on common shares or any other shares of Canadian Exchange Co. ranking junior to the exchangeable shares, other than stock dividends payable in common shares or in any such other shares of Canadian Exchange Co. ranking junior to the exchangeable shares, as the case may be;



•

redeem or purchase or make any capital distribution in respect of common shares or any other shares of Canadian Exchange Co. ranking junior to the exchangeable shares with respect to the payment of dividends or the distribution of the assets in the event of a liquidation, dissolution or winding-up of Canadian Exchange Co., whether voluntary or involuntary, or any other distribution of the assets of Canadian Exchange Co. among its shareholders for the purpose of winding up its affairs;



•

redeem or purchase or make any capital distribution in respect of any other shares of Canadian Exchange Co. ranking equally with the exchangeable shares with respect to the payment of dividends or the distribution of assets in the event of the liquidation, dissolution or winding up of Canadian Exchange Co., whether voluntary or involuntary, or any other distribution of the assets of Canadian Exchange Co. among its shareholders for the purpose of winding up its affairs; or



•

issue any shares of stock other than exchangeable shares, common shares and any other shares not ranking junior to the exchangeable shares, other than by way of stock dividends to holder of exchangeable shares,

unless, in the case of the first three bullet points above, all dividends and distributions on the outstanding exchangeable shares corresponding to dividends and distributions declared and paid to date on the shares of our common stock have been declared and paid in full on the exchangeable shares.

Amendment and Approval

        The rights, privileges, restrictions and conditions attaching to the exchangeable shares may be added to, changed or removed only with the approval of the holders of the exchangeable shares. Any approval required to be given by the holders of the exchangeable shares to add to, change or remove any right, privilege, restriction or condition attaching to the exchangeable shares or any other matter requiring the approval or consent of the holders of the exchangeable shares as a separate class (other than the election of a single director) shall be deemed to have been sufficiently given if it has been given in accordance with applicable law, subject to a minimum requirement that such approval be evidenced by a resolution passed by not less than 66²/3% of the votes cast on such resolution, excluding exchangeable shares beneficially owned by us or any of our subsidiaries, at a meeting of holders of exchangeable shares duly called and held at which the holders of at least 10% of the outstanding exchangeable shares at that time are present or represented by proxy.telephone number is (303) 262-0600.

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INTERESTSPLAN OF CERTAIN PERSONS IN THE ACQUISITION

Beneficial Ownership of and Trading in Exchangeable Shares

        Mr. McEwen, our Chairman, Chief Executive Officer and largest shareholder, beneficially owns 38,725,714 exchangeable shares of Canadian Exchange Co., which means that Mr. McEwen beneficially owns approximately 30% of the issued and outstanding exchangeable shares. Like the other holders of exchangeable shares, Mr. McEwen is entitled at any time at his option to exchange his exchangeable shares into shares of US Gold common stock on a one-for-one basis.

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SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS
AND MANAGEMENT OF US GOLDDISTRIBUTION

        As of December 1, 2011, there were a total of 136,559,845 shares of ourThe common stock and one share of our Series A Preferred Share issued and outstanding. Computershare Trust Company of Canadacovered by this prospectus is the holder of the one share of Series A Preferred Share as trusteeavailable for and on behalf of the registered holders of the 2007 Exchangeable Shares. The 2007 Exchangeable Shares were issueduse in connection with acquisitions by us of other businesses, assets, properties or securities.

        The amount and type of consideration we will offer and the other specific terms of any acquisition will be determined by negotiations with the owners or controlling persons of the Acquired Companiesbusinesses, assets, properties or securities to be acquired. We may structure business acquisitions in 2007. Asa variety of December 1, 2011, there were a total of 3,192,874 2007 Exchangeable Shares issued and outstanding (exclusive of shares owned by US Gold and its subsidiaries).

        Computershare Trust Company of Canada is entitled to allways, including acquiring stock, other equity interests or assets or properties of the voting rights, includingacquired business or merging the right to vote in personacquired business with us or by proxy, attaching to the one share of Series A Preferred Share on all matters that may properly come before our shareholders at a meeting of shareholders. The share of Series A Preferred Share is entitled to that number of votes, which may be cast by the Computershare Trust Company of Canada at any meeting at which our shareholders are entitled to vote, equal to the number of issued and outstanding 2007 Exchangeable Shares (other than shares held by US Gold or its subsidiaries). The holders of our common stock and the holders of the 2007 Exchangeable Shares vote together as a single class.subsidiaries. The 2007 Exchangeable Shares are exchangeableconsideration for shares of our common stock at any time on a one-for-one basis.

        The following table describes the beneficial ownership of our voting securities as of December 1, 2011 by: (i) each of our directors and "named executive officers" (as defined below); (ii) all of our officers and directors as a group; and (iii) each shareholder known to us to own beneficially more than 5% of our common stock (assuming for such purposes that the 2007 Exchangeable Shares owned by such persons, if any, constitute outstanding shares of our common stock). For purposes of providing the calculations below, we have assumed that the total numberbusiness acquisitions may consist of shares of our common stock outstanding is 139,752,719 (which assumes that the 3,192,874 2007 Exchangeable Shares constitute outstanding sharesor a combination of our common stock, but does not include any shares issuable upon exercisecash, notes, assumption of outstanding options except as set forth in the table). In calculating the percentage ownership for each shareholder, we assumed that any options owned by an individual and exercisable within 60 days are exercised, but not the options owned by anyliabilities or other individual. As of December 1, 2011, there were outstanding options to acquire 4,264,260 shares of our common stock, some of which are not exercisable within 60 days of the date of this prospectus. Unless otherwise stated, all ownership is direct and the address of each

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individual is the address of our executive office, 181 Bay Street, Bay Wellington Tower, Suite 4750, P.O. Box 792, Toronto, Ontario, Canada M5J 2T3.

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Changesregistration will be paid by us. It is not expected that underwriting discounts or commissions will be paid by us in Control

        On                        , 2012, we completed the Arrangement and acquired Minera Andes. We acquired Minera Andes in exchange for exchangeable shares of Canadian Exchange Co. which are exchangeable for shares of our common stock. In connection with the consummationissuances of the Arrangement, we issued 127,326,984 exchangeable shares of Canadian Exchange Co., which are exchangeable for 127,326,984 shares of our common stock. An additional 1,897,650 shares of US Gold common stock will be reserved for issuance upon exercise of Minera Andes options, which, together with the shares of US Gold issuable upon exchange of exchangeable shares of Canadian Exchange Co., represents approximately 47% of the voting power of US Gold on a fully diluted basis.

        We know of no other arrangement or events, the happening of which may result in a change in control.

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SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT OF
CANADIAN EXCHANGE CO.

        As of                        , 2012, there was a total of 150,001,000 shares of common stock of Canadian Exchange Co. and 127,326,984 exchangeable shares of Canadian Exchange Co. (exclusive of shares owned by US Gold and its subsidiaries) issued and outstanding. Callco is the sole owner of the issued and outstanding common stock of Canadian Exchange Co. The exchangeable shares were issuedunder this prospectus. However, finders' or similar fees may be paid from time to time in connection with the Arrangement.

        The number of directors of Canadian Exchange Co. is fixed at three. The holder of the common stock is entitled to annually elect two directorsspecific acquisitions, and the holders offees may be paid through the exchangeable shares are entitled to annually elect one director. In all other matters, the holder of the common stock and the holders of the exchangeable shares vote together, except for those matters where only holders of a specified class or particular series of shares are entitled to vote. The holder of the common stock is entitled to one vote per shareissuance of common stock of Canadian Exchange Co. and each holder of exchangeable shares is entitled to one vote per exchangeable share.

        In addition, holders of exchangeable shares, through the Series B Preferred Share, are entitled to vote together with the holders of our common stock and the holder of the Series A Preferred Share ascovered by this prospectus. Any person receiving a single class on all matters submitted to the shareholders of US Gold. The exchangeable shares are exchangeable for shares of US Gold common stock at any time on a one-for-one basis. All rights of a holder of exchangeable shares to exercise votes with the shareholders of US Gold or the shareholders of Canadian Exchange Co. will cease upon the exchange of that holder's exchangeable shares for shares of US Gold common stock.

        The following table describes the beneficial ownership of Canadian Exchange Co.'s voting securities as of                        , 2012 by: (i) each of its officers and directors; (ii) all of its officers and directors as a group; and (iii) each shareholder known to us to own beneficially more than 5% of Canadian Exchange Co.'s voting stock. As of                         , 2012, there were no outstanding options to acquire shares of Canadian Exchange Co.'s common stock or exchangeable shares. Unless otherwise stated, all ownership is direct and the address of each individual is the address of US Gold's, 181 Bay Street, Bay Wellington Tower, Suite 4750, P.O. Box 792, Toronto, Ontario Canada M5J 2T3.

Changes in Control

        On                        , 2012, we completed the Arrangement and acquired Minera Andes. In connection with the consummation of the Arrangement, Canadian Exchange Co. issued 127,326,984 exchangeable shares which represents 99.9% of the capital stock with certain voting rights of Canadian Exchange Co.

        We know of no other arrangement or events, the happening of which may result in a change in control.

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MATERIAL UNITED STATES FEDERAL INCOME TAX CONSEQUENCES

        In the opinion of Hogan Lovells US LLP, special counsel to US Gold, the following are, as of the date of this Prospectus, the material United States federal income tax considerations applicable, respectively, to U.S. Holders (as defined below) and Non-U.S. Holders (as defined below, and together with U.S. Holders, "Holders") with respect to the redemption, retraction or exchange of exchangeable shares for US Gold common stock.The following discussion does not address the United States federal income tax consequences or other tax consequences of the receipt of exchangeable shares by shareholders of Minera Andes in exchange for their shares of Minera Andes stock.

        This discussion is based upon provisions of the Internal Revenue Code of 1986, as amended (the "Code"), the related Treasury Regulations, judicial decisions, and administrative determinations as of the date of this document. Those authoritiesfee may be changed, perhaps retroactively, so that the United States federal income tax consequences may be different from those discussed below. This discussion is included for general information purposes only and does not purportdeemed to be a complete technical analysis or listing of all potential U.S. tax consequences that may be relevant to a Holder. Further, this summary does not address any tax consequences arising under the income or other tax laws of any state, local or foreign jurisdiction or any tax treaties that may be relevant to a Holder in light of its particular circumstances. It is not intended to be, nor should it be construed as being, legal or tax advice. The discussion herein is not binding on the Internal Revenue Service or the courts, and no assurance can be given that the discussion of tax consequences set forth herein will be sustained if challenged by the Internal Revenue Service.

        Except where noted, this discussion deals only with Holders who hold their exchangeable shares and US Gold common stock as capital assetsan underwriter within the meaning of Section 1221the Securities Act. We may also pay certain financial advisory or similar fees or reimburse certain expenses of the Code, and does not address the United States federal income tax consequences applicableinvestment banking firms that advise us from time to you if you are subject to special treatment under the United States federal income tax laws, including, for example, if you are:

•

time generally or regarding a broker or dealer in securities or currencies;



•

a financial institution;



•

a regulated investment company;



•

a real estate investment trust;



•

a tax-exempt organization;



•

an insurance company;



•

a person holding exchangeable shares, or shares of US Gold common stock, as part of a hedging, integrated, conversion, wash or constructive sale transaction or a straddle or synthetic security;



•

a trader in securities that has elected the mark-to-market method of accounting for your securities;



•

a person liable for alternative minimum tax;



•

a person who acquired exchangeable shares, or shares of US Gold common stock, in exchange for Minera Andes stock that was acquired in a compensatory transaction;



•

a Non-U.S. Holder who is or has previously been engaged in the conduct of a trade or business in the United States;



•

a person who is an investor in a pass-through entity;

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•

a person who owns (or is deemed to own) 10% or more of the voting stock of Canadian Exchange Co.;



•

a U.S. Holder whose "functional currency" is not the U.S. dollar;



•

a "controlled foreign corporation;"



•

a "passive foreign investment company;"



•

a U.S. expatriate or former long-term resident of the U.S.;



•

a Non-U.S. Holder owning more than 5% of the US Gold common stock; or



•

an S corporation, an entity taxable as a partnership for U.S. federal income tax purposes or other pass-through entity.

        If a partnership holds exchangeable shares that are exchanged for shares of US Gold common stock, the tax treatment of a partner will generally depend upon the status of the partner and the activities of the partnership. If you are a partner of a partnership holding exchangeable shares that are exchanged for shares of US Gold common stock, you are urged to consult your tax advisor.

As discussed below, there are substantial uncertainties regarding the United States federal income tax treatment of exchangeable shares and of the exchange of exchangeable shares for shares of US Gold common stock. You are strongly urged to consult your own tax advisor regarding the United States federal tax consequences applicable to the redemption, retraction or exchange of exchangeable shares and your ownership and disposition of US Gold common stock in light of your particular circumstances. In addition, you should also consult your tax advisor regarding any foreign, state, local, provincial, or other taxes or tax treaties that may be applicable to you.

        For purposes of this discussion, a "U.S. Holder" means a beneficial owner of exchangeable shares that is for U.S. federal income tax purposes:

•

an individual citizen or resident of the United States;



•

a corporation (or any other entity treated as a corporation for United States federal income tax purposes) created or organized in or under the laws of the United States, any state of the United States or the District of Columbia;



•

an estate the income of which is subject to United States federal income taxation regardless of its source; or



•

a trust if it (1) is subject to the primary supervision of a court within the United States and one or more U.S. persons have the authority to control all substantial decisions of the trust or (2) has a valid election in effect under applicable U.S. Treasury regulations to be treated as a U.S. person.

        For purposes of this disclosure, you are a "Non-U.S. Holder" if you are not a U.S. Holder.

Consequences of a Redemption, Retraction or Exchange of Exchangeable Shares

        The United States federal income tax consequences of a redemption, retraction or exchange of exchangeable shares depend, in part, on whether the exchangeable shares are treated for United States federal income tax purposes as shares of Canadian Exchange Co. or as shares of US Gold common stock. There is, however, no direct authority under current United States federal income tax law concerning whether the exchangeable shares should be treated as shares of US Gold common stock or shares of Canadian Exchange Co., and the classification for tax purposes of such exchangeable shares as shares of US Gold common stock or shares of Canadian Exchange Co. is therefore uncertain. Accordingly, the following discussion addresses the United States federal income tax consequences of aspecific acquisition.

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redemption, retraction or exchange of exchangeable shares under each of two alternative characterizations of the exchangeable shares: (1) based on the treatment of the exchangeable shares as shares of US Gold common stock, and (2) based on the treatment of the exchangeable shares as shares of Canadian Exchange Co. The discussion does not address the United States federal income tax consequences of any payments for accrued and unpaid dividends on the exchangeable shares.

        The following discussion is not binding on the Internal Revenue Service or the courts. There can be no assurance that the Internal Revenue Service will not assert and prevail with respect to a position that is adverse or contrary to a position taken by a U.S. Holder on such U.S. Holder's tax returns. Accordingly, it may be prudent for a U.S. Holder to assume the least favorable United States federal income consequences. Moreover, neither US Gold, Minera Andes, nor Canadian Exchange Co. has requested or intends to request a ruling from the Internal Revenue Service or an opinion of counsel with respect to whether the exchangeable shares should be treated as shares of US Gold common stock or shares of Canadian Exchange Co. In addition, no ruling has been or will be sought from the Internal Revenue Service as to the United States federal income tax consequences of a retraction, redemption, or exchange of exchangeable shares for shares of US Gold common stock.

Consequences if the Exchangeable Shares are Treated as Shares of US Gold Common Stock

U.S. Holders and Non-U.S. Holders

        If the exchangeable shares are treated as shares of US Gold common stock, the redemption, retraction or exchange of exchangeable shares for shares of US Gold common stock should not be a taxable event to a U.S. Holder or a Non-U.S. Holder. In that case, a Holder's holding period for the US Gold common stock received should include such Holder's holding period for the exchangeable shares that were exchanged for such shares of US Gold common stock, and the Holder's tax basis for such US Gold common stock should equal the Holder's tax basis for the exchangeable shares that were exchanged for such stock.

Consequences if the Exchangeable Shares are not Treated as Shares of US Gold Common Stock

U.S. Holders

        Subject to the discussion below entitled "Passive Foreign Investment Companies," if the exchangeable shares are not treated as shares of US Gold for United States federal income tax purposes, the redemption, retraction or exchange of exchangeable shares for shares of US Gold common stock should be treated as a fully taxable exchange for United States federal income tax purposes. Consequently, upon the exchange of a U.S. Holder's exchangeable shares, a U.S. Holder should recognize gain or loss, if any, equal to the difference between (i) the sum of the fair market value, as of the exchange date, of the shares of US Gold common stock received in the exchange and (ii) the U.S. Holder's tax basis in the exchangeable shares surrendered. Any such gain or loss on the exchange will generally be capital gain or loss. Capital gains of individuals derived with respect to capital assets held for more than one year are eligible for reduced rates of taxation, currently at 15% for dispositions on or prior to December 31, 2012, and 20% thereafter. The deductibility of capital losses is subject to limitations. A U.S. Holder's tax basis in shares of US Gold common stock received in the exchange will equal the fair market value of those shares as of the exchange date. A U.S. Holder's holding period for the US Gold common stock received will begin on the day after the exchange.

        In determining whether the exchangeable shares are shares of Canadian Exchange Co. or shares of US Gold common stock, U.S. Holders of exchangeable shares should consider that the Internal Revenue Service may assert and prevail with respect to a position that is adverse to the position taken by a U.S. Holder. It may be prudent for a U.S. Holder with gain inherent in the exchangeable shares to assume that the redemption, retraction or exchange will be a taxable event. Conversely, it may be

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prudent for a U.S. Holder with loss inherent in the exchangeable shares to assume that the redemption, retraction or exchange will be treated as a non-taxable event so that no loss will be recognized. In either event, such a U.S. Holder should consult its own tax advisor regarding the filing of a refund claim.

Non-U.S. Holders

        If the exchangeable shares are not treated as shares of US Gold for U.S. federal income tax purposes, a Non-U.S. Holder generally will not be subject to United States federal income tax on any gain realized on the exchange of exchangeable shares for shares of US Gold common stock unless:

          (i)  the gain is effectively connected with the conduct by the Non-U.S. Holder of a trade or business in the United States or, if a tax treaty applies, the gain is attributable to a permanent establishment of the Non-U.S. Holder in the United States; or

         (ii)  the Non-U.S. Holder is an individual who is present in the United States for 183 days or more during the taxable year of disposition and certain other conditions set forth in the Code are met, unless an applicable income tax treaty provides otherwise.

        If a Non-U.S. Holder is described in clause (i) above, the Non-U.S. Holder generally will be subject to the rules discussed above under the heading "—Consequences if the Exchangeable Shares are not Treated as Shares of US Gold Common Stock—U.S. Holders." In addition, if a corporate Non-U.S. Holder is described under clause (i) above, it may be subject to an additional branch profits tax on effectively connected income at a 30% rate (or lower applicable treaty rate). If an individual Non-U.S. Holder is described in clause (ii) above, the individual generally will be subject to a flat 30% tax (or lower applicable treaty rate) on the gain derived from a sale or exchange, which may be offset by certain United States capital losses.

Passive Foreign Investment Companies

        In general, if exchangeable shares held by a U.S. Holder are treated as shares of Canadian Exchange Co. and Canadian Exchange Co. is treated for United States federal income tax purposes as a "passive foreign investment company" ("PFIC"), gain recognized on the retraction, redemption or exchange of exchangeable shares will be taxed under the passive foreign investment company "excess distribution regime," unless the U.S. Holder has made a timely "qualified electing fund" election or "mark-to-market" election. The passive foreign investment company rules are extremely complex and could, if they apply to exchangeable shares owned by a U.S. Holder, have a significant adverse effect on the taxation of gain recognized by a U.S. Holder. However, we do not expect that the exchangeable shares would be treated as PFIC shares with respect to a U.S. Holder if none of the Minera Andes shares that such U.S. Holder exchanged for such exchangeable shares were treated as PFIC shares in the hands of such U.S. Holder. We understand from the management of Minera Andes that Minera Andes was a PFIC prior to January 1, 2007 but that it has not been a PFIC since that date. We have not independently verified this information. Based on such information received from Minera Andes, exchangeable shares may be treated as shares of a PFIC with respect to any U.S. Holder who held stock of Minera Andes prior to January 1, 2007, and such U.S. Holders are therefore urged to consult their own tax advisors to determine the potential applicability of the PFIC rules to their particular circumstance and any available elections.

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Consequences of Ownership and Disposition of Shares of US Gold Common Stock

Receipt of Distributions on US Gold Common Stock

U.S. Holders

        Distributions, if any, received with respect to shares of US Gold common stock out of US Gold's current or accumulated earnings and profits, as determined for United States federal income tax purposes, will be taxable as dividend income to U.S. Holders. In the case of non-corporate U.S. Holders, dividend income is currently (through December 31, 2012) subject to tax at the same preferential rates as net capital gains if certain requirements are satisfied; after December 31, 2012, such dividends will be taxable at the rates generally applicable to ordinary income. To the extent that the amount of any distribution exceeds US Gold's current and accumulated earnings and profits for a taxable year, the distribution will first be treated as a tax-free return of capital to the extent of the U.S. Holder's tax basis, and any excess will be treated as gain from the disposition of the common stock (discussed below under the heading "—Gain or Loss on Disposition of US Gold Common Stock—U.S. Holders").

Non-U.S. Holders

        Distributions, if any, received with respect to shares of US Gold common stock out of US Gold's current or accumulated earnings and profits, as determined for United States federal income tax purposes, will be subject to a withholding tax as discussed below. Any portion of a distribution that exceeds US Gold's current and accumulated earnings and profits will first be applied to reduce the Non-U.S. Holder's basis in the common stock, and, to the extent such portion exceeds the Non-U.S. Holder's basis, the excess will be treated as gain from the disposition of the common stock, the treatment of which is discussed below under "—Gain or Loss on Disposition of US Gold Common Stock—Non-U.S. Holders." In addition, if US Gold is a United States real property holding corporation or "USRPHC," as discussed below, and if any distribution exceeds its current and accumulated earnings and profits, US Gold will need to choose to satisfy its withholding tax requirement either by treating the entire distribution as a dividend, subject to the withholding tax under the following paragraph (and withhold at a minimum rate of 10% or such lower rate as may be specified by an applicable income tax treaty for distributions from an USRPHC), or by treating only the amount of the distribution equal to its reasonable estimate of its current and accumulated earnings and profits as a dividend, subject to the withholding tax rules in the following paragraph, with the excess portion of the distribution subject to withholding at a rate of 10% or such lower rate as may be specified by an applicable income tax treaty as if such excess were the result of a sale of shares in a USRPHC (discussed below under the heading "—Gain or Loss on Disposition of US Gold Common Stock—Non-U.S. Holders") with a credit generally allowed against the Non-U.S. Holder's United States federal income tax liability in an amount equal to the amount withheld from such excess.

        Dividends paid to a Non-U.S. Holder of US Gold common stock will generally be subject to withholding of United States federal income tax at a 30% rate or such lower rate as may be specified by an applicable income tax treaty. In addition, a Non-U.S. Holder will be taxed in the same manner as a U.S. Holder on dividends received that are effectively connected with the conduct by the Non-U.S. Holder of a trade or business in the United States or, if a tax treaty applies, are attributable to a permanent establishment of the Non-U.S. Holder in the United States. In addition, a corporate Non-U.S. Holder may also be subject to an additional branch profits tax at a 30% rate (or lower applicable treaty rate) on dividend income that is effectively connected with a U.S. trade or business. A Non-U.S. Holder will be required to satisfy certification and disclosure requirements (including completing Internal Revenue Service Form W-8BEN, W-8ECI, or other applicable form) to claim treaty benefits or otherwise claim a reduction of, or exemption from, the U.S. withholding tax described above.

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Gain or Loss on Disposition of US Gold Common Stock

U.S. Holders

        A U.S. Holder will generally recognize gain or loss on any sale, exchange or other disposition of US Gold common stock equal to the difference between the U.S. Holder's adjusted tax basis in the US Gold common stock and the amount realized from the sale, exchange or other disposition. Gain or loss will generally be long-term capital gain or loss if the U.S. Holder's holding period is more than one year. In the case of non-corporate U.S. Holders, any long-term capital gain will generally be taxed at preferential United States federal income tax rates, currently at 15% for dispositions on or prior to December 31, 2012, and 20% thereafter. The deductibility of losses may be subject to limitations.

Non-U.S. Holders

        Any gain realized by a Non-U.S. Holder on the sale, exchange, or other disposition of US Gold common stock will generally not be subject to United States federal income tax unless:

          (i)  the gain is effectively connected with the conduct by the Non-U.S. Holder of a trade or business in the United States or, if a tax treaty applies, the gain is attributable to a permanent establishment of the Non-U.S. Holder in the United States;

         (ii)  the Non-U.S. Holder is an individual who is present in the United States for 183 days or more during the taxable year of disposition and certain other conditions set forth in the Code are met, unless an applicable income tax treaty provides otherwise; or

        (iii)  US Gold is or has been a "United States real property holding corporation," or "USRPHC," as defined for United States federal income tax purposesand, as described below, the Non-U.S. Holder owns or is deemed to own more than 5% of US Gold's outstanding common stock.

        Under theForeign Investment in Real Property Tax Act of 1980 ("FIRPTA"), with respect to a Non-U.S. Holder's disposition of US Gold common stock, US Gold will be treated as a USRPHC if at any time during the shorter of (x) the five-year period ending on the date of disposition of shares of US Gold common stock or (y) the period during which a Non-U.S. Holder held shares of US Gold common stock, the fair market value of US Gold's "U.S. real property interests" equals or exceeds 50% of the sum of the fair market values of all of its interests in real property and all of its other assets used or held for use in a trade or business (as defined in applicable Treasury Regulations). Because US Gold owns substantial interests in real estate in the United States, US Gold believes that it may have been a USRPHC. Notwithstanding the foregoing, so long as the common stock of US Gold is regularly traded on an established securities market, as defined under applicable Treasury Regulations, Non-U.S. Holders who have never beneficially owned (or been deemed to own under certain attribution rules) more than 5% of the common stock of US Gold will generally not be subjected to United States federal income tax on gain realized on the sale, exchange or redemption of common stock solely because US Gold is or has been a USRPHC. US Gold believes that its common stock is currently treated as regularly traded on an established securities market.

        If a Non-U.S. Holder falls under clause (i) or (iii) above, the Non-U.S. Holder will generally be subject to the rules discussed above in the discussion titled "—Gain or Loss on Disposition of US Gold Common Stock—U.S. Holders", and, in the case of clause (iii) above, will generally be subject to a 10% withholding tax applied to the gross amount realized on the disposition. Any amount so withheld may be applied as a credit against the Non-U.S. Holder's United States federal income tax liability. If an individual Non-U.S. Holder falls under clause (ii) above, such individual generally will be subject to a flat 30% (or lower applicable treaty rate) tax on the gain derived from a sale, which may be offset by certain United States capital losses. In addition, if a corporate Non-U.S. Holder falls under clause (i)

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above, it may be subject to an additional branch profits tax on effectively connected income at a 30% rate (or lower applicable treaty rate).

        The foregoing summary of the possible application of the FIRPTA rules to Non-U.S. Holders is only a summary of certain material aspects of these rules. Because the U.S. federal income tax consequences to a Non-U.S. Holder under FIRPTA may be significant and are complex and subject to uncertainty, Non-U.S. Holders are urged to discuss those consequences with their tax advisors.

Information Reporting and Backup Withholding

U.S. Holders

        Information reporting and backup withholding may apply with respect to payments of dividends on US Gold common stock and to certain payments of proceeds on the sale or other disposition of our common stock. Certain non-corporate U.S. Holders may be subject to U.S. backup withholding (currently at a rate of 28%) on payments of dividends on our common stock and certain payments of proceeds on the sale or other disposition of our common stock unless the beneficial owner of such common stock furnishes US Gold or its agent with a taxpayer identification number, certified under penalties of perjury, and certain other information, or otherwise establishes, in the manner prescribed by law, an exemption from backup withholding.

        U.S. backup withholding tax is not an additional tax. Any amounts withheld under the backup withholding rules may be allowed as a refund or a credit against a U.S. Holder's U.S. federal income tax liability, which may entitle the U.S. Holder to a refund, provided the U.S. Holder timely furnishes the required information to the Internal Revenue Service.

Non-U.S. Holders

        US Gold must report annually to the Internal Revenue Service and to each Non-U.S. Holder the amount of dividends paid to such Non-U.S. Holder and the tax withheld with respect to such dividends, regardless of whether withholding was required. Copies of the information returns reporting such dividends and withholding may also be made available to the tax authorities in the country in which the Non-U.S. Holder resides under the provisions of an applicable income tax treaty.

        A Non-U.S. Holder will not be subject to backup withholding on dividends paid to such Non-U.S. Holder, or on the proceeds received by a Non-U.S. Holder from a sale or other disposition of US Gold common stock, as long as such Non-U.S. Holder certifies under penalty of perjury that it is a Non-U.S. Holder (and the payor does not have actual knowledge or reason to know that such Non-U.S. Holder is a United States person as defined under the Code), or such Non-U.S. Holder otherwise establishes an exemption.

        U.S. backup withholding tax is not an additional tax. Any amounts withheld under the backup withholding rules may be allowed as a refund or a credit against a Non-U.S. Holder's United States federal income tax liability provided the required information is timely furnished to the Internal Revenue Service.

Recently Enacted Legislation Relating to Foreign Owners

        Beginning with payments made after December 31, 2012, recently enacted legislation will impose a 30% withholding tax on dividends on US Gold common stock and the gross proceeds of a disposition of US Gold common stock paid to: (i) a foreign financial institution (as that term is defined in Section 1471(d)(4) of the Code) unless that foreign financial institution enters into an agreement with the U.S. Treasury Department to collect and disclose information regarding U.S. account holders of that foreign financial institution (including certain account holders that are foreign entities that have U.S. owners) and satisfies other requirements; and (ii) a foreign entity that is not a financial institution

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unless such entity certifies that it does not have any substantial U.S. owners or provides the name, address and taxpayer identification number of each substantial U.S. owner and such entity satisfies other specified requirements. Non-U.S. Holders should consult their own tax advisors regarding the application of this legislation to them.

THE PRECEDING DISCUSSION OF U.S. FEDERAL INCOME TAX CONSEQUENCES IS FOR GENERAL INFORMATION ONLY AND IS NOT LEGAL ADVICE. EACH SHAREHOLDER IS ENCOURAGED TO CONSULT ITS OWN TAX ADVISOR AS TO PARTICULAR TAX CONSEQUENCES, INCLUDING THE APPLICABILITY AND EFFECT OF ANY STATE, LOCAL AND NON-U.S. TAX LAWS, AND OF ANY PROPOSED CHANGES IN APPLICABLE LAWS.

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MATERIAL CANADIAN FEDERAL INCOME TAX CONSEQUENCES

        In the opinion of Fraser Milner Casgrain LLP, Canadian counsel to US Gold, the following is a summary of the material Canadian federal income tax consequences pursuant to theIncome Tax Act (Canada) (the "Tax Act") generally applicable to holders of exchangeable shares who (i) have acquired exchangeable shares pursuant to the Arrangement Agreement, (ii) have exchanged their exchangeable shares for shares of US Gold common stock in a retraction (a voluntary exchange initiated by a holder of exchangeable shares), redemption (an exchange initiated by Canadian Exchange Co. to redeem the exchangeable shares) or purchase (including a purchase of the exchangeable shares by Callco or US Gold, or a purchase of exchangeable shares by Canadian Exchange Co for cancellation) pursuant to the terms set forth in the exchangeable share provisions (attached to the Plan of Arrangement, and also included in the Articles of Incorporation of Canadian Exchange Co.), and (iii), at all relevant times for the purposes of the Tax Act (a) are, for the purposes of the Tax Act and any applicable income tax treaty or convention, resident or deemed to be resident in Canada, (b) hold such shares as capital property, and (c) deal at arm's length with, and are not affiliated with, each of Canadian Exchange Co. and US Gold ("Resident Shareholders"). Generally, such shares will constitute capital property to a Resident Shareholder thereof unless such securities are held in the course of carrying on a business of trading or dealing in securities or were acquired in one or more transactions considered to be an adventure or concern in the nature of trade. Resident Shareholders who do not hold their exchangeable shares or US Gold common stock as capital property, as the case may be, should consult their own tax advisors with respect to their particular circumstances.

        This summary is not applicable to a Resident Shareholder (i) that is a "financial institution" for purposes of the mark-to-market rules contained in the Tax Act, (ii) that is a "specified financial institution" as defined in the Tax Act, (iii) an interest in which is a "tax shelter" or a "tax shelter investment" as defined in the Tax Act, (iv) with respect to whom US Gold is a "foreign affiliate", as defined in the Tax Act, (v) who is exempt from paying tax under Part I of the Tax Act, or (vi) who reports their Canadian tax results for purposes of the Tax Act in a currency of a country other than Canada. Any such Resident Shareholders should consult their own tax advisors.

        This summary is based on the facts and assumptions set out in this document, the current provisions of the Tax Act and the regulations thereunder, counsel's understanding of the current published administrative policies and assessing practices of the Canada Revenue Agency ("CRA") publicly available prior to the date of this document. This summary takes into account all proposed amendments to the Tax Act and the regulations thereunder that have been publicly announced by or on behalf of the Minister of Finance (Canada) prior to the date hereof ("Proposed Amendments") and assumes that such Proposed Amendments will be enacted substantially as proposed. However, no assurance can be given that such Proposed Amendments will be enacted in the form proposed, or at all.

        This summary is not exhaustive of all possible Canadian federal income tax considerations applicable to the holding of US Gold Shares or Exchangeable Shares. Except for the Proposed Amendments, this summary does not take into account or anticipate any other changes in law or any changes in the CRA's administrative policies and assessing practices, whether by judicial, governmental or legislative action or decision, nor does it take into account other federal or any provincial, territorial or foreign tax legislation or considerations, which may differ from the Canadian federal income tax considerations described herein

This summary is of a general nature only and is not, is not intended to be, and should not be construed to be, legal, business or tax advice to any particular Resident Shareholder. Resident Shareholders should consult their own tax advisors as to the tax consequences to them from the holding and disposition of exchangeable shares or US Gold common stock.

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This summary does not address any tax consequences to holders that are not resident (or deemed resident) in Canada, such as U.S. residents.

All holders of exchangeable shares should consult their own tax advisors having regard to their particular circumstances.

        For purposes of the Tax Act, all amounts relating to the acquisition, holding or disposition of US Gold common stock, including the receipt of dividends and the calculation of any adjusted cost base amounts and proceeds of disposition, must be converted into Canadian dollars generally based on the Bank of Canada noon spot exchange rate on the date such amounts arise.

Redemption, Retraction or Purchase of Exchangeable Shares

        On a redemption (including a retraction) or purchase of an exchangeable share by Canadian Exchange Co., a Resident Shareholder will be deemed to have received a dividend equal to the amount, if any, by which the "redemption proceeds" exceed the paid-up capital (for purposes of the Tax Act) of the exchangeable share at the time of redemption. For these purposes, the "redemption proceeds" will be the fair market value at the time of the redemption, retraction or purchase, as the case may be, of the US Gold common stock received upon the redemption, retraction or purchase plus any other amount received by the Canadian Shareholder as part of the consideration other than amounts required to be included in income as a dividend. On the redemption or purchase, the Resident Shareholder will also be considered to have disposed of the exchangeable share for proceeds of disposition equal to the "redemption proceeds" less the amount of such deemed dividend. The Resident Shareholder will generally realize a capital gain (or a capital loss) equal to the amount by which such proceeds of disposition, net of any reasonable costs of disposition, exceed (or are less than) the adjusted cost base to the Resident Shareholder. In the case of a Resident Shareholder that is a corporation, in some circumstances the amount of any deemed dividend arising on the redemption of exchangeable shares may be treated as proceeds of disposition and not as a deemed dividend in accordance with specific rules in the Tax Act. Such Resident Shareholders should consult their own tax advisors concerning this possibility. For a description of the tax treatment of capital gains and losses, see "Material Canadian Federal Income Tax Consequences—Taxation of Capital Gains and Losses", below.

Dividends on Exchangeable Shares

        In the case of a Resident Shareholder who is an individual (other than certain trusts), dividends received or deemed to be received on the exchangeable shares will be included in computing a Resident Shareholder's income and will be subject to the gross-up and dividend tax credit rules that apply to taxable dividends received from taxable Canadian corporations. Provided that appropriate designations are made by Canadian Exchange Co. at the time the dividend is paid or is deemed to be paid, such dividend will be treated as an "eligible dividend" for the purposes of the Tax Act and a Resident Shareholder who is an individual will be entitled to an enhanced dividend tax credit in respect of such dividend. There are limitations on the ability of a corporation to designate dividends and deemed dividends as eligible dividends.

        In the case of a Resident Shareholder that is a corporation, dividends received or deemed to be received on the exchangeable shares will generally be required to be included in computing the corporation's income for the taxation year in which such dividends are received and such dividends will generally be deductible in computing the corporation's taxable income (subject to the discussion above under the heading "Material Canadian Federal Income Tax Consequences—Redemption, Retraction or Purchase of Exchangeable Shares").

Corporate shareholders should consult their own tax advisors for advice with respect to the potential application of these provisions.

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        A Resident Shareholder that is a "private corporation" (as defined in the Tax Act) or any other corporation resident in Canada and controlled or deemed to be controlled by or for the benefit of an individual or a related group of individuals may be liable under Part IV of the Tax Act to pay a refundable tax of 33¹/3% on dividends received or deemed to be received on the exchangeable shares to the extent that such dividends are deductible in computing the Resident Shareholder's taxable income. A Resident Shareholder that, throughout the relevant taxation year, is a "Canadian-controlled private corporation" (as defined in the Tax Act) may be liable to pay an additional refundable tax of 6²/3% on its "aggregate investment income" (as defined in the Tax Act), including any dividends that are not deductible in computing taxable income.

Exchange of Exchangeable Shares with US Gold or Callco

        On the exchange of an exchangeable share by the Resident Shareholder with US Gold or Callco for US Gold common stock, a Resident Shareholder will generally realize a capital gain (or a capital loss) to the extent the proceeds of disposition of the exchangeable share, net of any reasonable costs of disposition, exceed (or are less than) the adjusted cost base to the Resident Shareholder of the exchangeable share immediately before the exchange. For these purposes, the proceeds of disposition will be the fair market value at the time of the exchange of the US Gold common stock received upon exchange plus any other amount received by the Resident Shareholder from US Gold, Callco or any other subsidiary of US Gold as part of the exchange consideration other than amounts required to be included in income as a dividend. For a description of the tax treatment of capital gains and losses, see "Material Canadian Federal Income Tax Consequences—Taxation of Capital Gains or Capital Losses" below. The acquisition by US Gold or Callco of an exchangeable share from the Resident Shareholder thereof will not result in a deemed dividend to the Resident Shareholder.

Disposition of Exchangeable Shares other than on Redemption, Retraction or Exchange

        A disposition or deemed disposition of an exchangeable share by a Resident Shareholder, other than on the redemption, retraction or exchange of the shares, will generally result in a capital gain (or a capital loss) to the extent that the proceeds of disposition, net of any reasonable costs of disposition, exceed (or are less than) the adjusted cost base to the Resident Shareholder of such exchangeable shares immediately before the disposition. For a description of the tax treatment of capital gains and losses, see "Material Canadian Federal Income Tax Consequences—Taxation of Capital Gains or Capital Losses" below.

Dividends on US Gold Common Stock

        Dividends on US Gold common stock will be included in the recipient's income for the purposes of the Tax Act. Such dividends received by a Resident Shareholder who is an individual will not be subject to the gross-up and dividend tax credit rules in the Tax Act. A Resident Shareholder that is a corporation must include such dividends in computing its income and will not be entitled to deduct the amount of the dividends in computing its taxable income.

        A Resident Shareholder of US Gold common stock that, throughout the relevant taxation year, is a "Canadian-controlled private corporation" (as defined in the Tax Act) may be liable to pay a refundable tax of 6²/3% on its "aggregate investment income" (as defined in the Tax Act), including dividends received on US Gold shares that are not deductible in computing taxable income.

        A Resident Shareholder of US Gold common stock may be entitled to a foreign tax credit or deduction for any United States non-resident withholding tax paid on dividends received on US Gold common stock to the extent and under the circumstances provided in the Tax Act.

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Acquisition and Disposition of US Gold Common Stock

        The cost of US Gold common stock received on the retraction, redemption or exchange of an exchangeable share will be equal to the fair market value of such US Gold common stock at the time of such event and will generally be averaged with the adjusted cost base of any other US Gold common stock held at that time by the Resident Shareholder as capital property for the purpose of determining the Resident Shareholder's adjusted cost base of such US Gold common stock.

        A disposition or deemed disposition of US Gold common stock by a Resident Shareholder will generally result in a capital gain (or capital loss) to the extent that the proceeds of disposition, net of any reasonable costs of disposition, exceed (or are less than) the adjusted cost base to the Resident Shareholder of the US Gold common stock immediately before the disposition. For a description of the tax treatment of capital gains and losses, see "Material Canadian Federal Income Tax Consequences—Taxation of Capital Gains or Capital Losses" below.

Taxation of Capital Gains or Capital Losses

        Generally, one-half of any capital gain (a "taxable capital gain") realized by a Resident Shareholder in a taxation year must be included in the Resident Shareholder's income for the year, and one-half of any capital loss (an "allowable capital loss") realized by a Resident Shareholder in a taxation year must be deducted from taxable capital gains realized by the Resident Shareholder in that year (subject to and in accordance with rules contained in the Tax Act). Allowable capital losses for a taxation year in excess of taxable capital gains for that year generally may be carried back and deducted in any of the three preceding taxation years or carried forward and deducted in any subsequent taxation year against net taxable capital gains realized in such years, to the extent and under the circumstances described in the Tax Act.

        A Resident Shareholder that, throughout the relevant taxation year, is a "Canadian-controlled private corporation" (as defined in the Tax Act) may be liable to pay a refundable tax of 6²/3% on its "aggregate investment income" (as defined in the Tax Act), including any taxable capital gains.

        If the Resident Shareholder is a corporation, the amount of any capital loss realized on a disposition or deemed disposition of such share may be reduced by the amount of dividends received or deemed to have been received by it on such share (and in certain circumstances a share exchanged for such share) to the extent and under circumstances prescribed by the Tax Act. Similar rules may apply where a corporation is a member of a partnership or a beneficiary of a trust that owns such shares or where a trust or partnership of which a corporation is a beneficiary or a member is a member of a partnership or a beneficiary of a trust that owns any such shares. Resident Shareholder to whom these rules may be relevant should consult their own tax advisors.

Alternative Minimum Tax

        Individuals and certain trusts that receive or are deemed to receive taxable dividends on exchangeable shares or US Gold common stock, or realize a capital gain on the disposition or deemed disposition of exchangeable shares or US Gold common stock, may realize an increase in their liability for alternative minimum tax under the Tax Act.

Foreign Property Information Reporting

        In general, a "specified Canadian entity" for a taxation year or fiscal period whose total cost amount of "specified foreign property" (both as defined in the Tax Act) at any time in the year or fiscal period exceeds C$100,000, is required to file an information return for the year or period disclosing prescribed information, including the cost amount, any dividends received in the year, and any gains or losses realized in the year in respect of such property. On March 4, 2010, Proposed

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Amendments to expand existing reporting requirements with respect to specified foreign property to require more detailed information were announced. As of the date hereof, no detailed legislative proposals or revised administrative policies with respect to such amended reporting requirements have been made public. Subject to certain exceptions, a Resident Shareholder will be a specified Canadian entity.

        Specified foreign property is defined in the Tax Act to include shares of the capital stock of a non-resident corporation and property that, under the terms or conditions thereof or any agreement related thereto, is convertible into, exchangeable for or confers a right to acquire, property that is a share of the capital stock of a non-resident corporation. As such, exchangeable shares and US Gold common stock are specified foreign property to a Resident Shareholder. Accordingly, Resident Shareholders of exchangeable shares or US Gold common stock should consult their own tax advisors regarding compliance with these rules.

Offshore Investment Fund Property

        The Tax Act contains rules which, in certain circumstances, may require a Resident Shareholder of US Gold common stock to include in income in each taxation year an amount in respect of the acquisition and holding of interests in "offshore investment fund property". Both of the following conditions must be satisfied in order for these rules to apply in respect of US Gold common stock held by a resident of Canada:

(a)

the US Gold common stock may reasonably be considered to derive its value, directly or indirectly, primarily from portfolio investments in: (i) shares of the capital stock of one or more corporations, (ii) indebtedness or annuities, (iii) interests in one or more corporations, trusts, partnerships, organizations, funds or entities, (iv) commodities, (v) real estate, (vi) Canadian or foreign resource properties, (vii) currency of a country other than Canada, (viii) rights or options to acquire or dispose of any of the foregoing, or (ix) any combination of the foregoing (collectively, "Investment Assets"); and



(b)

it must be reasonable to conclude, having regard to all the circumstances, that one of the main reasons for the Resident Shareholder acquiring, holding or having the US Gold common stock was to derive a benefit from portfolio investments in Investment Assets in such a manner that the taxes, if any, on the income, profits and gains from such assets for any particular year are significantly less than the tax that would have been applicable under Part I of the Tax Act had the income, profits and gains been earned directly by such Resident Shareholder.

        If applicable, these rules would generally require a Resident Shareholder of US Gold common to include in income for each taxation year in which such Resident Shareholder holds the US Gold common stock, the amount, if any, by which (i) an imputed return for the taxation year computed on a monthly basis and calculated as the product obtained when the Resident Shareholder's "designated cost" (as defined in the Tax Act) of the US Gold common stock at the end of the month is multiplied by 1/12th of the applicable prescribed rate for the period that includes such month; exceeds (ii) the Resident Shareholder's income, including dividends received, from the US Gold common stock for the year (other than capital gains) determined without reference to these rules.

        On August 27, 2010, Proposed Amendments to the rules governing the taxation of investments in "offshore investment fund property", which included a proposed increase in the applicable prescribed rate, were released. Any amount required to be included in computing a shareholder's income in respect of US Gold common stock under these rules would be added to the adjusted cost base to the Resident Shareholder of such share.

These rules are complex and their application depends, to a large extent, on the reasons for acquiring or holding US Gold common stock. Resident Shareholders are urged to consult their own tax advisors regarding the application and consequences of these rules.

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UNAUDITED PRO FORMA FINANCIAL INFORMATION

        The following unaudited pro forma financial data should be read in conjunction with (i) "Management's Discussion and Analysis of Financial Condition and Results of Operations" from our annual report on Form 10-K for the fiscal year ended December 31, 2010; (ii) our consolidated financial statements and the notes thereto included in our annual report on Form 10-K for the fiscal year ended December 31, 2010; (iii) "Management's Discussion and Analysis of Financial Condition and Results of Operations" from our quarterly report on Form 10-Q for the quarterly period ended September 30, 2011; and (iv) our consolidated financial statements and the notes thereto included in our quarterly report on Form 10-Q for the quarterly period ended September 30, 2011, each of which is incorporated into the prospectus by reference.

        The following unaudited pro forma consolidated financial data are derived from our consolidated financial statements and certain historical financial data in respect of various assets acquired by us. The unaudited pro forma consolidated balance sheet as of September 30, 2011 has been prepared assuming the Arrangement and all necessary ancillary transactions and the exchange offer had been consummated on September 30, 2011. The unaudited pro forma consolidated income statement for the nine months ended September 30, 2011 and the year ended December 31, 2010 have been prepared assuming the Arrangement and all necessary ancillary transactions and the exchange offer had been consummated as of January 1, 2010. The pro forma consolidated financial data set forth on the attached unaudited pro forma consolidated balance sheet and unaudited pro forma consolidated income statement reflect the Arrangement and the issuance of our common stock in exchange for the exchangeable shares upon completion of the exchange offer as if they occurred on the dates hereinabove set forth.

        The historical consolidated financial statements have been adjusted in the unaudited pro forma consolidated financial statements to give effect to the pro forma events that are: (1) directly attributable to the Arrangement; (2) factually supportable; (3) utilizing reconciliations from Canadian generally accepted accounting principles ("Canadian GAAP") to United States generally accepted accounting principles ("US GAAP") contained in the notes to the Minera Andes audited financial statements for the fiscal year ended December 31, 2010; and (4) reconciliations from International Financial Reporting Standards ("IFRS") to US GAAP, presented in Minera Andes' interim financial statements for the period ended September 30, 2011.

        The unaudited pro forma consolidated financial statements do not reflect any cost savings (or associated costs to achieve such savings) from operating efficiencies or other restructuring that could result from the Arrangement. Further, the unaudited pro forma consolidated financial statements do not reflect the effect of any regulatory actions that may impact the unaudited pro forma consolidated financial statements when the Arrangement is completed.

        Transaction costs related to the Arrangement and exchange offer have been and will continue to be recorded as expenses in the periods in which these costs are incurred. The unaudited pro forma consolidated income statement for the nine months ended September 30, 2011 reflects such expenses incurred through September 30, 2011.

        The acquisition of Minera Andes' common stock by US Gold in the Arrangement will be accounted for in accordance with the acquisition method of accounting and the regulations of the Securities Exchange Commission. The purchase price will be determined on the basis of the fair value on the acquisition date of the shares of US Gold's common stock issued in the Arrangement. The purchase price for the unaudited pro forma consolidated financial statements is based on the closing share price of US Gold common stock on the NYSE on November 23, 2011, of $3.89 and the exchange of Minera Andes' outstanding shares of common stock for the right to receive 0.45 of a share of US Gold common stock.

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        Assumptions and estimates underlying the unaudited pro forma consolidated financial statements are described in the accompanying notes, which should be read in conjunction with the unaudited pro forma consolidated financial statements. Since the unaudited pro forma consolidated financial statements have been prepared based on preliminary estimates, the final amounts recorded at the date of the Arrangement may differ materially from the information presented. These estimates are subject to change pending further review of the assets acquired and liabilities assumed.

        The unaudited pro forma consolidated financial data is not indicative of our financial position or our results of operations which would actually have occurred if the Arrangement and exchange offer had occurred at the dates presented or which may be obtained in the future. In addition, future results may vary significantly from the results reflected in such statements.

        The unaudited pro forma consolidated financial data include financial information received from Minera Andes and such financial information has been accepted and incorporated as presented without independent verification of such financial information.

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UNAUDITED PRO FORMA CONSOLIDATED STATEMENTS OF OPERATIONS
AND COMPREHENSIVE (LOSS) INCOME
For the nine month period ended September 30, 2011
(in thousands)