To avoid breaking law, De Beers seeks water licence change

De Beers, which owns the Snap Lake diamond mine in N.W.T., says it can't meet a new chloride discharge limit that will come into effect in January.

Company says it can't meet new chloride discharge limit that will come into effect in January

Employees work underground at De Beers Snap Lake diamond mine in N.W.T. (CBC)

De Beers is seeking several changes to its water licence for the Snap Lake diamond mine, with one change aimed at preventing the company from breaking the terms of its licence.

On Jan.1, a new monthly limit for how much chloride can be pumped into Snap Lake will go into effect. That limit, 160 milligrams per litre, is lower than the current limit of 310 milligrams per litre.

The chloride, plus other mineral salts, come from groundwater that is pumped out of the mine and into the lake. 

De Beers says the impending new limit is impossible for the company to achieve — in other words, that the company would likely go over the new limit for chloride some time after Jan. 1.

According to the Northwest Territories government, penalties for breaking the terms of a water licence range from a verbal warning to court proceedings. De Beers has previously said that if it was found to be out of compliance, one of several outcomes could be shutting down the mine. Snap Lake employed approximately 275 northern residents as of 2012.

To avoid that fate, De Beers has asked the Mackenzie Valley Land and Water Board to immediately push back the effective date of the new limit, to June 2020 — ensuring that the current 310-milligram-per-litre limit remains. 

The board is seeking comments until Dec. 4 and is expected to make a decision before Jan. 1.

Additional changes requested

De Beers is also asking for a longer-term change, one that, once put in place, would supersede the temporary measure. 

The company has asked the land and water board to completely remove the limit for chloride in the water it pumps into the lake. Instead, the company wants chloride to be regulated as one of several components of total dissolved solids (TDS) and it wants the limit for TDS to be set at 850 milligrams per litre, from January to December 2015.

By then, a final limit on how much TDS can be dumped into Snap Lake for the remainder of the mine's life will have likely been set by the land and water board, which is also reviewing a separate, earlier water licence amendment application that De Beers filed last December and that underwent an environmental assessment. 

The number of additional water licence changes requested by De Beers in the last month — and their intertwined timelines — is beginning to bewilder at least one N.W.T. aboriginal group that has expressed concerns about mineral salt levels in Snap Lake.

"I'm confused about a lot of things here," wrote Todd Slack with the Yellowknives Dene's land and environment department, in a recent letter to De Beers and the land and water board.

To help flesh out the regulatory process for dealing with all these requested changes, the land and water board has released a timeline.

That timeline does not include a public hearing to discuss pushing back the compliance date for the new monthly limit for chloride.

The Snap Lake Environmental Monitoring Agency has written that such a public review "may be warranted."