Windfall Mine Project

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Information on the projet


Minière Osisko inc.

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Project summary

The proponent, Minière Osisko inc., intends to develop an underground gold mine 115 km east of Lebel-sur-Quévillon, in the Nord-du-Québec region of Eeyou Istchee James Bay. In addition to the underground mine, the mining complex will include an ore processing plant, a backfill plant, a tailings storage facility, a waste rock stockpile, an industrial water treatment plant, and a mine effluent, as well as a workers’ camp (300 individuals).

The underground mine will be accessible by ramp and operated by drifts with conventional methods of drilling, blasting, loading, and hauling of ore. The processing plant will be located at the Windfall site will have a nominal processing capacity of 3,400 tpd. According to the proponents’ mining plan, approximately 12.2 Mt of ore and 8.5 Mt of waste rock is expected to be mined over a 10-year timeframe.

A 69 kV power line from Waswanipi to the Windfall project site will be constructed to supply the mine with electricity and will be managed by an entity independent of Minière Osisko.

The new facilities will be grouped together to ensure optimal development, minimizing encroachment on the natural environment, facilitating circulation between facilities, ensuring better management of activities, and improving employee safety.

The construction phase of the project is expected to last approximately 18 months. The closure phase, decommissioning and reclamation activities, are expected to last approximately two years. It should be noted that environmental monitoring will continue following the closure of the project, notably for the monitoring of the final mine effluent and groundwater quality. A post-restoration monitoring program adapted to the sites to be restored, the restoration techniques in place and the contaminants present will also be conducted.


Preliminary information

Environmental and social impact assessment

Project Summary

Documents produced by COMEX

Documents produced by MELCCFP

Table provided by MELCCFP


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