Investigation, Remediation and Cost Allocation of Contaminants from the Britannia Mine in British Columbia: A Case Study

摘要

Federal and provincial regulations exercise an important role in the remediation of the former Britannia mine site. Although the Fisheries Act remains one of the most important pieces of Canadian environmental legislation and is applicable to this site, the Remediation Orders have been issued under provincial legislation, the Waste Management Act. Both levels of government are committed to the complete remediation and cost allocation to clean up the site. To this effect, the BCMWLAP recently issued three requests for proposals, one for contaminated sites, another for a feasibility study of a wastewater treatment plant, and the third, characterization of the site hydrogeology. The forensic evidence suggests that the main source of contamination at Britannia mine is acid mine drainage from copper leaching originated during the operating life of the mine. Some acid mine drainage may have occurred naturally prior to the development of the mine due to the geological formation of the mountains where the mine was located. The sources of acid mine drainage appear to be located in the open basins and tunnels, which originally were open pits that became basins as mining of the mountain progressed. Mining took place on and within ore bodies located between Furry Creek and Britannia Creek. Relatively little impact would have been noticeable from the ore body prior to mining to Britannia Creek, Furry Creek and Howe Sound. Investigation into the sediments of Howe Sound may show the relative increase in copper contamination with the onsite mining one hundred years ago. The timing and release of acid mine drainage commenced shortly after the mine opened and began extracting ore from the site. Dissolved metals released into Howe Sound represent a long-term environmental problem if left unmitigated, rather than the metal content of the submerged tailings. A water treatment plant is proposed to address the effluent flow, consider the mine hydrology, diversion assessments and internal mine workings to minimize the acid mine drainage from entering into the various surface water bodies surrounding the former copper mine. Measures to cover exposed sulphide mineralization to reduce contact with water and air. Measures to include the diversion of uncontaminated water away from the sulphide mineralization including open pits and underground mine workings.