Alamos Gold Inc. - Environmental Compliance Approval (sewage)

This proposal is to amend Environmental Compliance Approval (ECA) - Industrial Sewage Work (ISW) number 5775-CVTHWE issued on September 29, 2023, for the Island Gold Mine (the site), owned and operated by Alamos Gold Inc. (Alamos).

The existing approval covers the sewage works for the collection, treatment and disposal of mill tailings, process water, and mine water from the Lochalsh underground workings from the Island Gold Mine operations and processing facilities to be operated at a production rate not to exceed 461,760 tonnes per year of gold bearing ore, discharging up to approximately 27,214 cubic metres per day to Goudreau Creek discharging to Goudreau Lake. The existing approval also covers existing treatment of sanitary sewage and subsurface disposal of treated effluent, rated at a total maximum daily flow of 34,000 litres per day. The existing works consists of one tailings and primary pond, one secondary pond, and two sewage works comprising of septic tanks, partially raised leaching beds and sand mantles.

Alamos is submitting this application to include the installation of a new sewage system and updated monitoring plan. The sewage system is planned to be located approximately 500 metres southeast of the new Shaft area, with the purpose of treating domestic water from washrooms and shower facilities to be used by workers on that part of the site. The sewage system comprises a septic system with a natural attenuation. The location of the sewage system was identified as shallow bedrock with low risk of impact to current and future use of groundwater as a drinking water source. Alamos is also proposing an updated Monitoring Program to include additional new surface and groundwater monitoring locations at existing site components, as well as the proposed sewage system.