Monitoring at the Lorraine Mine Site: A Follow-Up on the Remediation Plan

Abstract

The Lorraine mine site, located in the Temiscamingue region, Quebec, Canada, was operated from 1964 to 1968, generating approximately 600,000 tons of tailings disposed in a pond area making 15.5 hectares. These tailings, exposed to atmospheric conditions for 30 years, have oxidized and are generating acid seepage. In 1998, the Quebec Ministry of Natural Resources (MRN), who owns the site, decided to do rehabilitation work to limit the environmental impact from acid mine drainage. A five steps remediation program was commissioned in 1998 and consisted of: 1) remodeling the tailings area, 2) construction of a layered cover with capillary barrier effects (CCBE) over the reactive tailings, 3) construction of limestone drains at the final effluent, 4) soil quality improvement outside tailings area, and 5) implementation of a monitoring program. The purpose of the CCBE, which constitute the main expenditure, is to limit the infiltration of oxygen and water to the reactive mine tailings. After construction of the cover, instruments were installed on site to monitor the CCBE performance and assess the evolution of water quality. The authors present in this paper the results from two years of monitoring at this site.