Gravity is the enemy

Pumping at Giant to continue for decades

Richard Gleeson
Northern News Services

Yellowknife (Mar 23/01) - The battle against gravity in the dank passages beneath Giant mine is nowhere close to being over.

For decades pumps have been pulling water from beneath the mine to the surface, artificially lowering the water table, keeping it from coming into contact with the 265,000 tons of arsenic trioxide dust stored underground.

Dave Nutter

"The pumping is going to go on for decades to come," said Dave Nutter, who is heading up the federal clean-up of the mine.

A pre-feasibility study of the costs, advantages and disadvantages of six different approaches to dealing with the poisonous and water soluble dust is due in a month.

The study will pare back the number of approaches to dealing with the arsenic problem to two or three. It will form the basis of an arsenic trioxide management plan the Department of Indian Affairs and Northern Development must submit to the Mackenzie Valley Land and Water Board by Oct. 1.

Nutter cautioned actually beginning the work of dealing with the problem is still far off.

"We're looking at four to five years before we start implementing what we feel is the best solution," he said.

The arsenic trioxide dust -- enough to fill the Precambrian Building seven times -- is stored in 15 chambers between 80 and 250 feet below the surface.

The battle against gravity is also being fought against water seeping down from the surface.

Meltwater has sifted through the fissures and cracks in the rock above, penetrated the vaults, dissolved some of the arsenic then flowed out of the chamber.

"The water we're standing in contains high levels of arsenic trioxide," noted Nutter during a tour of the mine Thursday.

Five centimetre arsenic trioxide icicles hang from the rough stone ceiling near one of the six-metre thick bulkheads plugging one of the vaults.

The arsenic-laced water that flows out of the mine mixes with the rest of the 1,362 litres per minute that flows through the mine.

The water is caught in a sump and pumped to the tailings pond to await treatment.

Federal officials are offering a public briefing on progress in the clean up of Giant mine.

An open house will be held Monday and Tuesday from noon to 5:30 p.m. at Storefront in the Centre Square Mall.

An evening presentation will be given Tuesday from 7:30 p.m. to 9 p.m.

Also, look in next Friday's Yellowknifer for a special report on Giant mine's arsenic situation.