AMENDED AND RESTATED JOINT FILING AGREEMENT

Exhibit 99.4

AMENDED AND RESTATED JOINT FILING AGREEMENT

     Pursuant to this Amended and Restated Joint Filing Agreement, the undersigned acknowledge and agree that the foregoing Schedule 13D, as amended, is filed on behalf of each of the undersigned and that all subsequent amendments to this Statement on Schedule 13D may be filed on behalf of each of the undersigned without the necessity of filing additional joint filing agreements. This Amended and Restated Joint Filing Agreement replaces in its entirety the Joint Filing Agreement, dated January 7, 2010, filed as Exhibit 99.1 to the Schedule 13D filed on January 7, 2010 by the parties thereto.

Dated:  February 2, 2010

	TONGLING NONFERROUS METALS GROUP HOLDINGS CO., LTD.
	By:	/s/  Xxxxxxxx XX
		Name:	Xxxxxxxx XX
		Title:	Chief Engineer
	CHINA RAILWAY CONSTRUCTION CORPORATION LIMITED
	By:	/s/  Xxxxxxxx XXXX
		Name:	Xxxxxxxx XXXX
		Title:	Company Vice President
	CRCC-TONGGUAN INVESTMENT CO., LTD.
	By:	/s/  Xxxxxxx XXX
		Name:	Xxxxxxx XXX
		Title:	Director
	CRCC-TONGGUAN INVESTMENT (CANADA) CO., LTD.
	By:	/s/  Xxxxxxx XXX
		Name:	Xxxxxxx XXX
		Title:	Chairman