UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): December 12, 2014

ALLIED NEVADA GOLD CORP.

(Exact name of Registrant as Specified in Its Charter)

(775) 358-4455

(Registrant’s Telephone Number, Including Area Code)

n/a

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

As previously announced, on December 12, 2014, Allied Nevada Gold Corp., a Delaware corporation (the “Company”), closed the Company’s previously announced public offering (the “Offering”) of shares of common stock, par value $0.001 per share (“Common Stock”), and warrants to purchase shares of Common Stock.

As a condition to the closing of the Offering, a Lock-up Agreement, dated as of December 12, 2014 (the “Lock-up Agreement”), was entered into between the Company and certain of its officers and directors in the form of the Lock-up Agreement attached hereto as Exhibit 10.1 and incorporated herein by reference. Each of the officers and directors who executed a Lock-up Agreement agreed that, for a period of 60 days from the date of the closing of the Offering, he would not, without the prior written consent of the H.C. Wainwright & Co., LLC, the sole lead placement agent for the Offering, directly or indirectly, offer, sell, or transfer or agree to transfer, any shares of Common Stock, or any securities convertible into, or exercisable or exchangeable for, shares of Common Stock, or otherwise enter into any transaction that would have the same effect, or enter into any arrangement that transfers to another, in whole or in part, any economic consequence of ownership of any of his shares of Common Stock.

This summary of the material terms of the Lock-up Agreement is qualified in its entirety by reference to the Form of Lock-up Agreement. Further information regarding the Offering is contained in the Company’s Current Reports on Form 8-K for December 9, 2014 and December 12, 2014 and filed with the Securities and Exchange Commission on such dates.

(d) Exhibits

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

EXHIBIT INDEX

Exhibit 10.1

December 12, 2014

Allied Nevada Gold Corp

9790 Gateway Drive, Suite 200

Reno, Nevada 89521

Re: Allied Nevada Gold Corp. - Lock-Up Agreement

Dear Sirs:

This Lock-Up Agreement is being delivered to you in connection with the Securities Purchase Agreement (the “Purchase Agreement”), dated as of December 9, 2014 by and among Allied Nevada Gold Corp., a Delaware corporation (the “Company”) and the investors party thereto (the “Buyers”), with respect to the issuance of shares of the Company’s common stock, par value $0.001 per share (the “Common Stock”). Capitalized terms used herein and not otherwise defined herein shall have the respective meanings set forth in the Purchase Agreement.

In order to induce the Buyers to enter into the Purchase Agreement, each undersigned agrees that, commencing on the date hereof and ending on the date sixty days following the Closing Date (the “Lock-Up Period”), the undersigned, without the prior written consent of H.C. Wainwright & Co., LLC, will not, and will cause all affiliates (as defined in Rule 144 promulgated under the Securities Act of 1933, as amended) of the undersigned or any person in privity with the undersigned or any affiliate of the undersigned not to, (i) offer, sell, offer to sell, contract or agree to sell, hypothecate, pledge, sell or grant any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend, make any short sale or otherwise transfer or dispose of or agree to dispose of, directly or indirectly, any shares of Common Stock or Common Stock Equivalents, or establish or increase a put equivalent position or liquidate or decrease a call equivalent position within the meaning of Section 16 of the Securities and Exchange Act of 1934, as amended and the rules and regulations of the Securities and Exchange Commission promulgated thereunder with respect to any shares of Common Stock or Common Stock Equivalents owned directly by any of the undersigned (including holding as a custodian) or with respect to which any of the undersigned has beneficial ownership within the rules and regulations of the Securities and Exchange Commission (collectively, the “Undersigned’s Shares”), or (ii) enter into any transaction that would have the same effect, or enter into any swap, hedge or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of any of the Undersigned’s Shares, whether any such transaction described in clause (i) or (ii) above is to be settled by delivery of shares of Common Stock or other securities, in cash or otherwise, (iii) make any demand for or exercise any right or cause to be filed a registration statement, including any amendments thereto, with respect to the registration of any shares of Common Stock or Common Stock Equivalents or (iv) publicly disclose the intention to do any of the foregoing.

The foregoing restriction is expressly agreed to preclude the undersigned, and any affiliate of the undersigned and any person in privity with the undersigned or any affiliate of the undersigned, from engaging in any hedging or other transaction which is designed to or which

reasonably could be expected to lead to or result in a sale or disposition of the Undersigned’s Shares even if the Undersigned’s Shares would be disposed of by someone other than the undersigned. Such prohibited hedging or other transactions would include, without limitation, any short sale or any purchase, sale or grant of any right (including, without limitation, any put or call option) whether or not with respect to any of the Undersigned’s Shares or whether or not with respect to any security that includes, relates to, or derives any significant part of its value from the Undersigned’s Shares.

Notwithstanding the foregoing, the undersigned may transfer (i) the Undersigned’s Shares as a bona fide gift or gifts, provided that the donee or donees thereof agree to be bound in writing by the restrictions set forth herein, or (ii) the Undersigned’s Shares to any trust for the direct or indirect benefit of the undersigned or the immediate family of the undersigned, provided that the trustee of the trust agrees to be bound in writing by the restrictions set forth herein, and provided further that any such transfer shall not involve a disposition for value. For purposes of this Lock-Up Agreement, “immediate family” shall mean any relationship by blood, marriage or adoption, not more remote than first cousin. The undersigned now has, and, except as contemplated by the immediately preceding sentence, for the duration of this Lock-Up Agreement will have, good and marketable title to the Undersigned’s Shares, free and clear of all liens, encumbrances, and claims whatsoever. The undersigned also agrees and consents to the entry of stop transfer instructions with the Company’s transfer agent (the “Transfer Agent”) and registrar against the transfer of the Undersigned’s Shares except in compliance with the foregoing restrictions.

In order to enforce this covenant, the Company shall impose irrevocable stop-transfer instructions preventing the Transfer Agent from effecting any actions in violation of this Lock-Up Agreement.

Each of the undersigned acknowledges that the execution, delivery and performance of this Lock-Up Agreement is a material inducement to each Buyer to complete the transactions contemplated by the Purchase Agreement and that the Company shall be entitled to specific performance of such undersigned’s obligations hereunder. Each undersigned hereby represents that such undersigned has the power and authority to execute, deliver and perform this Lock-Up Agreement, that such undersigned has received adequate consideration therefor and that such undersigned will indirectly benefit from the closing of the transactions contemplated by the Purchase Agreement. The undersigned hereby represent that there are no other affiliates of the undersigned that hold securities of the Company.

Each undersigned understands and agrees that this Lock-Up Agreement is irrevocable and shall be binding upon such undersigned’s heirs, legal representatives, successors, and assigns.

This Lock-Up Agreement may be executed in two counterparts, each of which shall be deemed an original but both of which shall be considered one and the same instrument.

This Lock-Up Agreement will be governed by and construed in accordance with the laws of the State of New York, without giving effect to any choice of law or conflicting provision or rule (whether of the State of New York, or any other jurisdiction) that would cause the laws of any jurisdiction other than the State of New York to be applied. In furtherance of the foregoing, the internal laws of the State of New York will control the interpretation and construction of this Lock-Up Agreement, even if under such jurisdiction’s choice of law or conflict of law analysis, the substantive law of some other jurisdiction would ordinarily apply.

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Agreed to and Acknowledged:

Allied Nevada Gold Corp.

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