Cyanide spill at Denton-Rawhide

Vancouver — The failure of a weld on a pipeline caused 40,000 gallons of dilute cyanide process solution to be spilled at the Denton-Rawhide gold mine in Nevada.

The ruptured pipe was carrying process solution from a lined storage pond to a lined heap-leach pad. Mine personnel took immediate actions to contain and neutralize the spilled solution, which had a concentration of about 140 parts cyanide per million parts of solution. The total spill amounted to roughly 47 pounds of cyanide.

“The Rawhide emergency response team went into action as soon as the ruptured pipeline weld was detected and did an effective job in the cleanup to ensure protection of the environment,” says the mine’s general manager, Kevin Hegerle.

About 300 tons of affected soil was placed back on the heap-leach pad, and areas that had minimal exposure were sprayed with a dilute solution of water and bleach (sodium hypochlorite) to neutralize any remaining cyanide. Some soils were not removed, so as to minimize disturbance to the environment.

The mine, owned 51% by Kennecott Minerals and 49% by Pacific Rim Mining, lies 90 km southeast of Fallon in Mineral Cty. Production began in 1990 and has averaged 100,000 oz. gold and 1 million oz. silver annually. The mine is in the process of planning for final reclamation and closure. Mining is scheduled to end during the second half of 2002.

“While the spill is unfortunate, we are pleased with the quick and efficient clean up response by our partner, Kennecott,” says Thomas Shrake, Pacific Rim’s chief executive officer. “The incident is being reviewed by the team on site to determine what can be done to minimize the possibility of a similar incident.”