Temporary increase in York River flow due to dewatering at Mines Gaspé

Description: The relaunch of Mines Gaspé in Murdochville will involve discharging mining effluent into Porphyre Creek, 3 km upstream of the York River. Studies have shown the presence of salmon in this creek. The project, including the dewatering of the mine, must respect the salmon populations of the York River. The two main issues are the effect of the increased flow on the watercourse and the increased load of certain contaminants, notably copper, in the water. The aim of the project is to acquire knowledge of the environment as early as the summer of 2024, in order to plan the work to be carried out in 2025 and subsequent years.

In the summer of 2024, information will be collected on flows, substrate type, juvenile salmon health, prevalence of saproligniasis infections, metal concentrations in water, salmon, brook trout if present and algal biofilms, and any relevant information that will provide a baseline to guide future work. Sampling will be carried out in Porphyre and Miller creeks and in the York River, both upstream and downstream of the confluence with Porphyre Creek. Field work and laboratory analyses at INRS are planned. CASF funding will cover the cost of metal analysis of fish and biofilm samples at INRS laboratories. Project objectives and performance measures are therefore limited to these analyses.The proposed project goes beyond the requirements that are expected as part of the government permit application for dewatering. The project will provide a better understanding of the distribution of contaminants in the fish food web in the York River and some of its tributaries. The results could provide indicators to explain the increased occurrence of saprolégniose in adult fish.