Project summary

The Grevet mining project received authorization on November 18, 1994 for the underground mining of a zinc and copper deposit at the rate of 2500 tonnes a day (seven days a week) for 10 years. The overburden was assessed at 15,000 cubic meters, and the mine produced about 1 million cubic meters of waste rock, 10,000 cubic meters of which is potentially acid-generating. Waste rock can be used in the construction of various infrastructures and as underground mine backfill, and the pile should contain about 200,000 m³ of non-reactive waste rock. The ore stockpile, which was not supposed to exceed 125,000 tonnes, was constructed on bedrock. The project connected to Lebel-sur-Quevillon via an existing road and the mine’s power was supplied via a 120 kV line to the Lebel substation. There was no worker housing on the site. Production came to a temporary halt on November 2, 2008, to start again in 2012.

This project is currently subject to an application to amend the certificate of authorization to increase the annual volume of effluent and modify the distribution of effluent discharges at different target periods. More specifically, the amendment request has the following objectives:

• Increase in the annual volume of the effluent to 3 900 000 cubic metres
• Re-allocation of final effluent releases at different target periods to better distribute them according to fluctuations in natural water supplies in the tailings pond.

Details on location

The Langlois mining site is located approximately 40 kilometers north of Lebel-sur-Quévillon. The Cree community closest to the mine site is Waswanipi.