Water Treatment, Windfall Lake Mine - ASDR Canada

Water Treatment, Windfall Lake Mine

Mandate and Objectives

The Windfall mine, owned by Osisko Mining Corporation, is located in the James Bay (Eeyou Itschee) territory in Quebec. ASDR’s mandate was to meet the requirements of Directive 019 on mining effluents during the dewatering and maintenance of underground galleries. The main contaminants to be treated were heavy metals and total suspended solids (TSS).

Challenges and Issues

  • Supplying a water treatment system for the treatment of suspended solids (SS), heavy metals and pH readjustment (acidification).
  • Storage of process sludge to allow dewatering and excavation.

Solutions and Achievements

ASDR developed a treatment process consisting of a caustic soda dosing unit, a flocculation unit and a sulfuric acid dosage unit. 

ASDR also provided specialized technicians to oversee the commissioning and operation of the plants. Environmental requirements were met at an average operating flow rate of 80 m³/h.


The pumping of the pit was carried out according to the criteria for discharge into the environment. Osisko took advantage of ASDR’s commercial flexibility which enabled them to rent and subsequently purchase the water treatment units.

  • Client Osisko Mining Corporation
  • Services provided Dewatering of a Pit
    and Treatment of Mining Water
  • Place Baie-James (Eeyou Itschee), Quebec

The Project in a Few Figures

m³ treated during the dewatering period

Other projects