Richard Gleeson
Northern News Services

Yellowknife (Mar 22/02) - The cause of a roof collapse at Con mine last weekend remains a mystery.

A spokesperson for the company that owns the mine said insurance adjusters have yet to inspect the 15-by-30-metre oxygen plant.

"We don't know what contributed to the failure," said Brian Labadie. "We won't know that until we dismantle the building."

In a press release issued Monday, Miramar Mining Corporation said no one was hurt in the collapse.

The building was constructed in 1991 for Nerco, the previous owner of Con Mine. Miramar purchased the Con property in 1993.

The plant supplies oxygen to the autoclave, used to separate gold from concentrates of ore mined at Con and Giant Mine.

A liquid oxygen tank outside the building was unaffected by the collapse, Miramar stated. Liquid oxygen is highly volatile. The tank has a storage capacity of 285 tonnes.

Labadie said the autoclave will not be operating for the next four to six weeks as a result of the collapse.

During the shutdown concentrates will be stockpiled. With excess processing capacity, Miramar expects to meet its production target of 130,000 ounces by the end of 2002.

"It doesn't change any of our long-term projections, none whatsoever," Labadie said.

The autoclave is also used to treat arsenic sludges, the byproduct of the refining processes used before the autoclave was built.

Miramar had projected to have all the sludges treated by the end of this year. Labadie said that target will now be pushed back a few months.

The collapse could increase operating costs at the mine by as much as $1.5 million this year, Miramar stated.

Most of the increase will come in the form of costs associated with transporting liquid oxygen to the mine.

Insurance coverage and adjustments to operations may reduce the costs.

"All that's still under investigation, who is responsible for what," Labadie said.

The plant was run by another company that Miramar paid for the oxygen produced for the autoclave.