MELBOURNE, June 6 (Reuters) - Australian diversified miner...

MELBOURNE, June 6 (Reuters) - Australian diversified miner South32 S32.AX has picked investment bank RBC Capital to help it put together a bid for Botswana's Khoemacau copper mine, a source familiar with the matter said on Tuesday.

The copper mine, which produces about 60,000 tonnes of copper and 1.6 million ounces of silver a year and has a mine life of more than 20 years is expanding to double production.

South32 Chief executive Graham Kerr said in April that the miner was looking to build on its copper book.

"We've got lots of options," he told media in Melbourne at the time. "We'll always look at things externally but it's going to be through the lens of value and not blowing up the balance sheet."

The potential bid, initially reported by the Australian Financial Review, would put the asset value at more than $2 billion.

South 32 and RBC declined to comment. Khoemacau did not immediately respond to a request for comment.