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NNSL Photo/graphic

Diavik Diamond mine at Lac de Gras must conduct stringent water monitoring tests in order to renew its water licence. - photo courtesy of Diavik Diamond Mines

Mine ordered to improve water monitoring

Jason Unrau
Northern News Services

Yellowknife (Dec 08/06) - Diavik Diamond Mines Inc. has been ordered to improve its aquatic monitoring program in order to renew its water licence.

The Wek'eezhii Land and Water Board's ruling reads in part, "Diavik must complete work on the Aquatic Effects Monitoring Program and Ammonia Management Plan in a manner satisfactory to the board, to ensure that Lac de Gras is protected during the continuation of the DDMI mining operation."

The board is hiring two expert panels to do a peer review of both the mine and intervenors' submissions to the board on the issues of aquatic effects monitoring and ammonia discharged from explosives used at the mine site.

Diavik mine's current water licence allows for a maximum 20 milligrams/litre of ammonia effluent.

According to Diavik, its current discharge levels are about 6 milligrams/litre.

"We try and keep water away from blast rock so it doesn't wash the ammonia residue from rock," said Diavik spokesperson Tom Hoefer.

"But when you're underground we know we're going to have a lot of water issues and virtually all that ammonia is going to be washed away and we're expecting (the current level) is going to go up."

Diavik's site at Lac de Gras currently consists of one open pit mine, formed by damming a portion of the lake, and more recent underground operations. Diavik estimates that by 2008, mining efforts would be concentrated solely on its underground interests at the site, expected to be in production until 2022.

Wek'eezhii Land and Water Board Executive Director Zabey Nevitt told Yellowknifer the level of allowable ammonia discharge remains to be seen.

"More work needs to be done to get to that figure," he said.

"What that figure should be to achieve the purposes of the record of agreement is either the original level or the lowest achievable practical limit."

While Canadian water quality guidelines list 20 milligrams/litre as an allowable limit, intervenors argued that in order to protect the pristine environment of Lac de Gras, lower discharge levels should be a condition of Diavik's water licence renewal.

With the mine's current licence set to expire on Aug. 31, 2007, both the mine and water board are confident adjustments can be made to the Aquatic Effects Monitoring Program and Ammonia Management Plan in time to ensure seamless mine operations.