Gold mining at the site took place over a period of about 35 years from about 1867 to 1902. Mine shafts were scattered throughout the site. The deepest mine shaft was the Gatling shaft at a depth of approximately152 metres. The ministry located and sealed all major mine shafts, and remediated all other mine features from 1993-1995. The draft proposed cleanup strategy for the mine area deals with remaining waste rock and contaminated soils.
Area: The Main Mine Area - 3 ha Remote Mine Area - 114 ha
Contaminants of Concern: Arsenic, low-level radioactive material
Volume of Wastes: Approximately 32,500 m3
Relocation/consolidation of highly contaminated wastes to the Industrial Area, placement of a soil cover in the remaining areas and treatment of groundwater from the Tuttle Shaft.
Consolidation of wastes
Highly contaminated materials (including radioactive slag) will be excavated and relocated to the Industrial Area, where they will be consolidated under an engineered cover that is 1.5 metres thick. “Clean” fill will replace the waste materials and the area will be vegetated.
Waste rock will be covered with a geofabric filter, clay, topsoil, (minimum total thickness 0.65 metres) and then vegetated.
Less contaminated areas will be covered with an engineered clay cap 1.5 metres thick.
Groundwater will continue to be pumped from the Main Mine Area, and treated at the Arsenic Treatment Plant.