Bioleach testing planned at Placer Dome gold mine

Bioleaching, which uses sulphide oxidizing bacteria to break down the sulphides in refractory ore deposits and liberate the gold locked insid e, is known to ha ve several advantages over conventional roasting methods.

There are no sulphur dioxide emissions associated with biotechnology and the resulting tailings material is also very stable, Shamrock President Ull i Rath tol d The Northern Miner.

While bioleaching technology has been used to treat gold concentrates in South Africa, it has yet to be adopted by many of the big North American gold produce rs.

According to Placer Dome spokesman Bill Thompson, the advantages of bioleaching with respect to the environment was the primary considerati on in the gold mine r’s decision to test the system.

Concentrates from Campbell are being tested as Coastech’s laboratories in Vancouver where recoveries in excess of 90% have been achieved.

A pilot plant also has been set up at the Campbell mine site. However, Rath said his company is still wondering what to do with the excessive amoun ts of pyrrh otite in the Campbell concentrates.

“We have been very encouraged by the gold recoveries we are getting,” said Rath.

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