Fisheries habitat compensation planning for mine drainage impacts at the Island Copper Mine

The Island Copper Mine closed in 1995 after 25 years of productive life. The closure plan for the site was updated in 2004 using a risk-based approach to assess site risks and associated contingency measures. Closure planning studies predicted that ARD would worsen over time, and two small headwater lakes (the Twin Lakes) remained exposed to risks from potential increases in metal loads over the long term. A number of potential mitigation options were examined, and ultimately the Twin Lakes drainage and diversion option was selected because its implementation would ensure that any worsening ARD at the site would not impact the watershed as a whole. The project proceeded after CEAA screening and the approval of provincial and federal agencies. Five compensatory projects were completed to meet an objective of 2:1 fish habitat compensation, prior to the authorized destruction of the Twin Lakes. Compensation costs for ideal and typical compensatory works were $6/m² to $40/m², respectively. The successful completion of the Twin Lakes drainage and diversion project has eliminated the risk of future mine-related ARD impacts to the Stephens Creek watershed, while maintaining fish habitat quality.Non UBCUnreviewedOthe