"We now procure nearly 50 per cent of copper concentrates we need through equity investments (in foreign mines)," said Koichi Fukushima, Sumitomo Metal Mining's president, in a recent interview. "We would like to boost the ratio to two thirds."

Japanese smelters are custom smelters whose major source of profits are treatment and refining charges (TC/RCs) paid by foreign miners for processing concentrates into refined metal.

As Japanese copper mines wind down, Japanese smelters have boosted equity investments in foreign mines to stabilise their concentrate procurements over the past decade.

Sumitomo Metal Mining (SMM) was not currently in any major talks to invest in foreign concentrate projects but it is looking for investment opportunities in existing projects or new offshore projects to secure additional copper concentrates through equity investments, Fukushima said.SMM now owns 12 per cent in the Morenci copper project of the United States, 15 per cent in La Candelaria in Chile, 13.3 per cent in Northparkes in Australia and 5.0 per cent in Batu Hijau in Indonesia.

The company already has established close business relationship with major producer, Phelps Dodge Corp, operator of the Morenci mine in Arizona, and solid ties with Canadian miner Tech Corp.

In April, SMM announced its revival plan, drafted as part of management efforts to help its earnings and reputation recover from damage caused by a nuclear accident last September at its wholly-owned subsidiary JCO Co.

Under the plan, SMM will boost electrolytic nickel and ferro-nickel production capacity in Japan to 85,000 tonnes per year from a current 55,000 tonnes. It also plans to raise copper output capacity to 250,000 tonnes a year by next April and ultimately to 400,000 tonnes a year from 230,000 tonnes now.

"SMM would like keep offering a variety of base metals such as gold, copper, nickel, and zinc. Of those, we see copper as our basics and also intend to boost our nickel business," Fukushima said.In April, it launched a feasibility study jointly with the Philippines' Rio Tuba Nickel Mining Corp on a laterite nickel project using new acid leaching technology. The study is scheduled to be completed by the end of December.

SMM shares traded up 8.67 per cent at 514 yen per share by 0427 GMT on Wednesday, more than double the year's trading low of 223 yen hit on January 5.Brokers said interest in SMM was re-ignited after the company mostly completed its compensation for Japan's worst-ever nuclear accident at JCO and launched its ambitious management strategy.