Abandoned Mines Site Characterizations and Clean-up Criteria - Case Studies
Mr Steve Reitzel, Ms Ljiljana Josic, Mr Henri Sangam
A lack of mine reclamation policy and regulations prior 1970s resulted in uncontrolled mining activities that historically affected its surrounding environment. The tailings were usually discharged directly to the environment without any containment. The tailings from gold production usually have potential to generate highly acidic drainage that is elevated in aluminum, arsenic, cobalt, copper, iron, manganese, and nickel and sulphate salinity. Over the years the tailings would migrated into surrounding environment creating large areas of contaminated soils and sediment. Transport of contaminants of concern associated with the tailings is via a combination of particulate transport of un-oxidised tailings and mobile loadings of acidity, metals and sulphate salinity. These transport processes are most prominent during higher surface water flow that comes with spring freshet / summer rainfall and if water levels drop in the lake and perched groundwater table. Canada has an estimated 10,000 abandoned mines. SNC-Lavalin has completed abandoned mine site characterisation studies to delineate contaminant extent across the sites. Following completion of site characterization, different remedial options were evaluated and a cleanup criterion was established for the site. This paper will discuss Case Studies for site characterization including historic overview of contaminant migration and proposed cleanup for the sites.