Pilot plant test by Giant Bay

Killer bugs have successfully broken down refractory gold ores north of the 60th Parallel. These aggressive little microbes attack in waves and the attrition rate is almost 100%, unheard of in conventional warfare. As if this isn’t enough, the hapless survivors are then bathed in cyanide which liberates the gold from the oxidized concentrate.

While this may sound like Armageddon, it’s actually modern science at work. Giant Bay Resources has just completed a pilot plant test of its bioleaching process at Giant Yellowknife’s now dormant Salmita operation in the Courageous Lake area. Dr Robert Handfield, a vice-president at Giant Bay, confirmed that gold has been poured from the bioleach test and Wright Engineers of Vancouver are currently completing a process evaluation study.

During a recent visit to the pilot operation, which was integrated into the Salmita mill, Dr Handfield said that “recoveries exceeded expectations,” which has significant implications for the area, particularly Noranda-Getty’s (N.M., Aug 24/87) Tundra gold discovery right next door.

The bioleach process uses bacteria to oxidize refractory ores where the gold is tied up in sulphides. These sulphides are changed to sulphates, allowing the gold to be recovered by chemical means, namely cyanide. The system is attractive environmentally, particularly over conventional roasting where sulphur dioxide and other contaminants are released into the atmosphere.

The material tested was from Salmita’s Red 24 zone which is very refractory and similar to the Tundra discovery. He said that Giant Yellowknife has been looking at a process to replace roasting which is used at its Yellowknife operations. He noted the company could ultimately end up controlling Giant Bay Resources.