LIMA, March 11 (Reuters) - Peru on Wednesday approved an

environmental study for Buenaventura, one of

Peru's largest mining firms, to proceed with its southern

Trapiche copper project with an estimated investment of $3.4

billion, the Andean nation's state certification office said.

The environmental certification office SENACE said the

evaluation of the detailed environmental impact study

"guarantees the development of activities under high

sustainability standards" in Peru's Apurimac region.

SENACE noted that while the study's approval is an essential

step, it does not in itself authorize the miner to begin

operations.

Peru is the world's third-largest copper producer.

Regulators in the South American country require other permits

including a construction license before miners can begin

extracting ore.

Executives at Buenaventura, which owns several gold and

silver mines across the country, have said Trapiche should

become one of the company's most important copper projects when

it becomes operational after 2030.

Buenaventura also owns close to 20% of Cerro Verde

, one of Peru's largest copper deposits. The mine

there is run by U.S.-based miner Freeport McMoRan ( FCX ).