Investments	12 Months Ended
Dec. 31, 2012
Investments, Debt and Equity Securities [Abstract]
Investments	Investments Boulder Wind Power, Inc. On September 13, 2011, the Company invested $20.0 million into Boulder Wind Power, Inc. Series B convertible preferred stock, which is accounted for at cost. At December 31, 2012, the Company estimated the fair value of this investment and determined it was not impaired. Intermetallics Japan Joint Venture On November 28, 2011, Molycorp, Daido Steel Co., Ltd. (“Daido”) and Mitsubishi Corporation (“Mitsubishi”) entered into a preliminary shareholders agreement for the purpose of establishing a new private company, IMJ, to manufacture sintered NdFeB permanent rare earth magnets. The capital contribution ratio of the newly formed company is 30.0% by Molycorp, 35.5% by Daido and 34.5% by Mitsubishi. According to the definitive shareholders agreement, which was signed in January 2012, Molycorp will contribute, upon achievement of certain milestones and subject to the approval of Molycorp’s Board of Directors, Japanese Yen (JPY) 2.5 billion in cash in exchange for ordinary shares of IMJ over a period of twelve months. The actual remittance amounts will vary depending on the future exchange rate between the U.S. dollar and the Japanese Yen, and the achievement of certain milestones by the joint venture. The Company contributed $27.7 million (representing JPY 2.2 billion) to IMJ thorough December 31, 2012. Molycorp accounts for this investment under the equity method because it has the ability to exercise significant influence over the operating and financial policies of IMJ, as evidenced by Molycorp’s ownership share and its proportional voting rights and representation in the Board of Directors of IMJ. The consolidated statement of operations and comprehensive income for the year ended December 31, 2012 includes a loss of $2.4 million associated with this equity method interest. Ganzhou Keli Rare Earth New Material Co., Ltd. As a result of the Molycorp Canada acquisition in June 2012, Molycorp acquired a 25% ownership interest in Ganzhou Keli Rare Earth New Material Co., Ltd. (“Keli”), a company that converts REO into metals for use in Neo Powders™. The purchase allocation attributable to this investment at the time of the Molycorp Canada acquisition was $12.2 million. Molycorp accounts for this ownership interest under the equity method because it has the ability to exercise significant influence over the operating and financial policies of Keli, as evidenced by Molycorp’s ownership share and its proportional voting rights. The consolidated statements of operations and comprehensive income include a loss of $1.2 million for the period from June 12, 2012 to December 31, 2012 associated with this equity method ownership interest. Toda Magnequench Magnetic Materials Co. Ltd. As a result of the Molycorp Canada acquisition in June 2012, Molycorp acquired a 33% ownership interest in Toda Magnequench Magnetic Materials Co. Ltd. (“TMT”), a company that produces rare earth magnetic compounds with Neo Powders™ supplied by Magnequench (Tianjin) Company Limited in its normal course of business. The purchase allocation attributable to this investment at the time of the Molycorp Canada acquisition was $1.6 million. Molycorp accounts for this ownership interest under the equity method because it has the ability to exercise significant influence over the operating and financial policies of TMT, as evidenced by Molycorp’s ownership share and its proportional voting rights. Ingal Stade GmbH As a result of the Molycorp Canada acquisition in June 2012, Molycorp acquired a 50% ownership interest in Ingal Stade GmbH (“Ingal Stade”), a joint venture facility in Stade, Germany, which extracts gallium metal from alumina smelter bayer liquor with purity level of 5N (99.999%) or higher. The purchase allocation attributable to this investment at the time of the Molycorp Canada acquisition was $4.9 million. Molycorp accounts for this ownership interest under the equity method. Atlantic Metals & Alloys, LLC As a result of the Molycorp Canada acquisition in June 2012, Molycorp acquired a 19.5% ownership interest in Atlantic Metals & Alloys, LLC, a company which provides refining services for residues and scrap of the rare and platinum group metals. The purchase allocation attributable to this investment at the time of the Molycorp Canada acquisition was $1.4 million. Molycorp accounts for this ownership interest under the cost method. At December 31, 2012, the fair value of this investment was not estimated as there were no identified events or changes in circumstances that may have had a significant adverse effect on the fair value of the investment. Vive Crop Protection As a result of the Molycorp Canada acquisition in June 2012, Molycorp acquired a 7% ownership interest in Vive Crop Protection, a company that specializes in the formulation of active ingredients used in crop protection. The purchase allocation attributable to this investment at the time of the Molycorp Canada acquisition was $0.9 million. Molycorp accounts for this ownership interest under the cost method. At December 31, 2012, the fair value of this investment was not estimated as there were no identified events or changes in circumstances that may have had a significant adverse effect on the fair value of the investment.

Investments

Boulder Wind Power, Inc.

On September 13, 2011, the Company invested $20.0 million into Boulder Wind Power, Inc. Series B convertible preferred stock, which is accounted for at cost. At December 31, 2012, the Company estimated the fair value of this investment and determined it was not impaired.

Intermetallics Japan Joint Venture

On November 28, 2011, Molycorp, Daido Steel Co., Ltd. (“Daido”) and Mitsubishi Corporation (“Mitsubishi”) entered into a preliminary shareholders agreement for the purpose of establishing a new private company, IMJ, to manufacture sintered NdFeB permanent rare earth magnets. The capital contribution ratio of the newly formed company is 30.0% by Molycorp, 35.5% by Daido and 34.5% by Mitsubishi. According to the definitive shareholders agreement, which was signed in January 2012, Molycorp will contribute, upon achievement of certain milestones and subject to the approval of Molycorp’s Board of Directors, Japanese Yen (JPY) 2.5 billion in cash in exchange for ordinary shares of IMJ over a period of twelve months. The actual remittance amounts will vary depending on the future exchange rate between the U.S. dollar and the Japanese Yen, and the achievement of certain milestones by the joint venture. The Company contributed $27.7 million (representing JPY 2.2 billion) to IMJ thorough December 31, 2012.

Molycorp accounts for this investment under the equity method because it has the ability to exercise significant influence over the operating and financial policies of IMJ, as evidenced by Molycorp’s ownership share and its proportional voting rights and representation in the Board of Directors of IMJ. The consolidated statement of operations and comprehensive income for the year ended December 31, 2012 includes a loss of $2.4 million associated with this equity method interest.

Ganzhou Keli Rare Earth New Material Co., Ltd.

As a result of the Molycorp Canada acquisition in June 2012, Molycorp acquired a 25% ownership interest in Ganzhou Keli Rare Earth New Material Co., Ltd. (“Keli”), a company that converts REO into metals for use in Neo Powders™. The purchase allocation attributable to this investment at the time of the Molycorp Canada acquisition was $12.2 million. Molycorp accounts for this ownership interest under the equity method because it has the ability to exercise significant influence over the operating and financial policies of Keli, as evidenced by Molycorp’s ownership share and its proportional voting rights. The consolidated statements of operations and comprehensive income include a loss of $1.2 million for the period from June 12, 2012 to December 31, 2012 associated with this equity method ownership interest.

Toda Magnequench Magnetic Materials Co. Ltd.

As a result of the Molycorp Canada acquisition in June 2012, Molycorp acquired a 33% ownership interest in Toda Magnequench Magnetic Materials Co. Ltd. (“TMT”), a company that produces rare earth magnetic compounds with Neo Powders™ supplied by Magnequench (Tianjin) Company Limited in its normal course of business. The purchase allocation attributable to this investment at the time of the Molycorp Canada acquisition was $1.6 million. Molycorp accounts for this ownership interest under the equity method because it has the ability to exercise significant influence over the operating and financial policies of TMT, as evidenced by Molycorp’s ownership share and its proportional voting rights.

Ingal Stade GmbH

As a result of the Molycorp Canada acquisition in June 2012, Molycorp acquired a 50% ownership interest in Ingal Stade GmbH (“Ingal Stade”), a joint venture facility in Stade, Germany, which extracts gallium metal from alumina smelter bayer liquor with purity level of 5N (99.999%) or higher. The purchase allocation attributable to this investment at the time of the Molycorp Canada acquisition was $4.9 million. Molycorp accounts for this ownership interest under the equity method.

Atlantic Metals & Alloys, LLC

As a result of the Molycorp Canada acquisition in June 2012, Molycorp acquired a 19.5% ownership interest in Atlantic Metals & Alloys, LLC, a company which provides refining services for residues and scrap of the rare and platinum group metals. The purchase allocation attributable to this investment at the time of the Molycorp Canada acquisition was $1.4 million. Molycorp accounts for this ownership interest under the cost method. At December 31, 2012, the fair value of this investment was not estimated as there were no identified events or changes in circumstances that may have had a significant adverse effect on the fair value of the investment.

Vive Crop Protection

As a result of the Molycorp Canada acquisition in June 2012, Molycorp acquired a 7% ownership interest in Vive Crop Protection, a company that specializes in the formulation of active ingredients used in crop protection. The purchase allocation attributable to this investment at the time of the Molycorp Canada acquisition was $0.9 million. Molycorp accounts for this ownership interest under the cost method. At December 31, 2012, the fair value of this investment was not estimated as there were no identified events or changes in circumstances that may have had a significant adverse effect on the fair value of the investment.