Richard Gleeson
Northern News Services

NNSL (Jan 20/99) - Right now it is overshadowed by Royal Oak's cash crisis, but one day the company, or some company, will have to clean up Giant Mine.

Fulfilling a requirement of its water licence, Royal Oak submitted an updated plan for the clean-up and reclamation of the mine last month.

But environmentalists and concerned members of the public will have to wait until next fall to find out about the biggest component of the clean-up -- dealing with the 182,000 tonnes of arsenic trioxide stored underground.

Giant is conducting an arsenic trioxide management study which is to conclude Oct. 1. The study was commissioned to answer the question of what to do with the arsenic trioxide stored at the mine. That plan will form part of the Giant clean-up plan.

In its submission to the water board last month, Giant outlined several options the study is investigating. Three deal with arsenic left in the ground, and three with the removal of it from the vaults:

• leave it underground and pump in air to enhance the re-establishment of permafrost to isolate the stored arsenic from the water table

• continue pumping out water to keep the water table depressed

• create 'preferential pathways' to divert groundwater from the storage vaults

• store material in a suitable surface facility

• convert the arsenic trioxide into ferric arsenate

• process it for sale

Arsenic trioxide is a toxic byproduct of the process, called gold roasting, used at Giant to separate gold from ore.

"This stuff is fairly toxic," said Kevin O'Reilly, research director for the Canadian Arctic Research Committee. "A teaspoon of this stuff, if you ingest it directly, will kill you. So there's probably enough there to kill the planet several times over."

High levels of airborne arsenic cause cancer of the lungs and other organs. In drinking water, high levels of arsenic are known to cause skin, bladder, kidney and lung cancer.

At Giant, it is the possibility of arsenic trioxide seeping into groundwater that poses the biggest risk.

"The water level is depressed because they're pumping water out to go down and do the mining," explained O'Reilly.

"Once those pumps are shut off, the water table starts to rise. Arsenic trioxide dissolves in water, so this stuff will get picked up by groundwater and move around into water bodies, like Great Slave Lake."

O'Reilly said he's seen estimates as high as $1 billion for the removal and processing of the arsenic dust at Giant.

Arsenic trioxide aside, Royal Oak estimates the rest of the clean-up will cost $9.2 million, plus another $334,594 in ongoing operating and monitoring costs.