De Beers Canada is taking the Mackenzie Valley Environmental Impact Review Board to court over its handling of the Gahcho Kue diamond project near Lutsel K'e, N.W.T.

De Beers alleges the board, which has thejobof determiningif the project is environmentally safe, was not thorough in its initial environmental assessment.

The diamond giant is calling on the courts to quash a board orderin June that requiresit to conduct a public environmental review.

De Beers says that instead of looking at the cumulative environmental effects of the project during that earlier assessment phase, the board referred the project to an environmental impact review, a long and costly process.

"The review board was required … to consider the impact of the development on the environment, including any cumulative impact that is likely to result, the significance of any such impact, and whether mitigative or remedial measures are necessary," the company's legal application states.

"The review board failed to consider these matters and instead deferred their consideration to the environmental impact review."

As a result, De Beers says the board erred in law and exceeded its jurisdiction.

De Beers is also wondering why the Gahcho Kue mine has to go through the more rigorous review than their Snap Lake project.

An open pit

Martin Haefele, who speaks for the Mackenzie Valley review board, says the difference is Snap Lake is an underground mine, while the Gahcho Kue project will be an open-pit mine near the treeline.

Haefele says it requires the draining of a lake and therefore poses a greater threat to fish and wildlife.

"As we all know, caribou numbers have declined in recent years and there is a very big concern the diamond mines may have something to do with it, and this one is proposed on a known migration route," he said.

The board wants theenvironmentaleffects of the mine to be discussed at public hearings in Lutsel K'e, Fort Resolution, Behchoko and Detah, the communities nearest the project, located about 300 kilometres northeast of Yellowknife.

Whether those hearings take place depends on the judgment of the territory's Supreme Court.

The application will go before a judge on Aug. 25.