Zijin Mining Group (SSE:601899,HKEX:2899) is China's most valuable gold producer, and the company looks to be investing more and more in mining projects outside the country. Last December, Zijin announced a C$81-million investment in Pretium Resources (TSX:PVG,NYSE:PVG) and that company's Brucejack project. It also bought a 9.9-percent stake in Ivanhoe Mines (TSX:IVN) in April, investing C$105 million to help advance Ivanhoe's projects in South Africa and the Democratic Republic of the Congo (DRC). Now, Zijin has invested in Ivanhoe again, putting up US$412 million for 49.5 percent of Ivanhoe's 95-percent stake in the Kamoa copper project. The company will also arrange project financing for 65 percent of the project and upon completion of the financing, will have the option to acquire an additional 1-percent interest. Zijin also made another big announcement on Tuesday — it's buying 50 percent of Barrick Gold's (TSX:ABX) 95-percent stake in the Porgera gold mine in Papua New Guinea for $298 million. The two companies have also signed a long-term agreement to collaborate on future projects and investments. Expanding interests Certainly, it appears that Zijin is making a major effort to expand its interests outside of China. "A strategic partnership with Barrick is an excellent fit for Zijin and a powerful combination as we look to expand our business globally outside of China," Chen Jinghe, Zijin's chairman, is quoted as saying in Barrick's release on Tuesday. Chen also said that Barrick has a "strong international operating presence," while Zijin has "unrivaled access to the Chinese market. Barrick Chairman John Thornton agrees that the relationship will be beneficial for both parties. "A twenty-first century mining company with global reach and the intention to become an industry leader must, by definition, have a distinctive relationship with China," he said in a statement, noting that China is the world's largest producer and consumer of gold. "Our partnership with Zijin is the first step in a long-term strategic relationship with one of China's leading mining companies."