Rio Tinto Group, the world's second biggest miner by market value, and Toronto-based CVRM may invest in mining projects in the Philippines to boost their production of copper and nickel, an official said.

CVRM may invest as much as $3 billion in a nickel mine if it finds a deposit from which it can produce 60,000 tons a year of the metal, Philippine Mining and Geoscieces Bureau Director Horacio Ramos said yesterday. Rio Tinto is yet to decide on how much money it will invest in the Philippines, he said.

"They're serious about investing in the Philippines," said Ramos. "They have sent technical experts to the country, opened offices and appointed a liaison to coordinate the paper work."

Philippines President Gloria Arroyo is aiming to attract $6 billion of investments in mining, which accounted for 1 percent of the $98 billion economy last year. The country's mineral wealth may be worth up to $1 trillion, the government has said.

Rio is looking for a "world class' project like Tampakan mine in southern Philippines, Ramos said. The mine contains 11.6 million tons of copper and 14.6 million ounce of gold, according to an initial study by Indophil Resources NL.

"Rio wants the government to guarantee that they will have a stable supply when they put in the money," he said, without elaborating on the concerns raised by the company.

The government's resolve to promote mining investments was put to test by the closure of the Philippine mining operation of Australia's Lafayette Mining Ltd. The $60 million project, the South Asian nation's first overseas-funded mine venture to open after investment rules changed in 2004, was ordered shut last year after two incidents of cyanide spills.

Lafayette Mining has passed all the tests ordered by the government to determine whether it has improved its facilities after the spills, Ramos said. The government had said it will allow the copper mine to fully reopen only after the company passes all the test's stages.