Pit Dewatering and Modular Water Treatment, Fenelon Gold Mine

Mandate and Goals

The Fenelon Gold Mine is Wallbridge Mining’s flagship project, located approximately 75 km from Matagami. ASDR was mandated by Wallbridge to dewater the pit and maintain the water level at set targets to ensure safe access to the underground operations. The project was designed to meet the requirements of the Mining Industry Directive 019 for environmental compliance. ASDR treated suspended solids and provided pH control, while managing heavy metals (As, Cu, Fe, Ni, Pb, Zn).

Challenges and Issues

• Supplying a modular water treatment system capable of managing flow rates between 50 m³/h and 250 m³/h
• Installing and starting-up dewatering systems during very difficult winter conditions
• Installing a floating barge using a helicopter to accelerate the dewatering process
• Installing geosynthetic bags in winter for sludge dewatering

Solutions and Achievements

For this project, ASDR implemented a water treatment process composed of five 20-foot containerized modules. More specifically, sodium hydroxide, coagulant and flocculant dosing units, a sodium hydroxide storage unit and an electrical room. More than 325,000 m3 were dewatered at an average flow rate of about 150 m3/h. The treatment plant maintained the underground facilities dry at site. 

ASDR also provided a floating barge with a 100 HP submersible pump for dewatering and water level maintenance. The sludge produced by the water treatment process was contained and dewatered with geosynthetic bags. ASDR pumped the water out of the pit in 45 days during harsh winter conditions to comply with environmental discharge criteria.