LOCATION: Baffin Island, Nunavut, Canada
The Nanisivik Mine is located at the northern end of Baffin Island in Nunavut, Canada. The mine site operated between 1976 and 2002 in which time it processed over 17 million tonnes of ore to produce over 150,000 and 2,500,000 tonnes of lead and zinc concentrate, respectively. In addition to ore, approximately 10,000,000 m3 of tailings were produced during the milling process.
BGC has been involved in the project since 2000, carrying out functions related to development, regulatory review and implementation of the closure plan. We are currently managing the performance monitoring program.
Some highlights of BGC’s contribution to the project follow:
- The tailings disposal area was reclaimed in 2004 and 2005 by constructing a permafrost aggradation cover over the tailings. The purpose of the cover was to encapsulate the tailings in permafrost to limit the potential negative environmental impacts associated with the tailings. During development of the closure plan, BGC undertook final design of the cover system including geothermal analysis with climate change considerations.
- Another unique aspect of reclaiming the tailings deposit was the freezeback of the unfrozen portions of the tailings deposit. This required a detailed assessment to determine if the freezeback of the tailings could have any negative impacts on the stability of the adjacent dike, the surface reclamation covers or the water quality within the system. BGC completed the geothermal freezeback analysis of the tailings deposit, using information collected during a multiphase geotechnical drilling and instrumentation program.
- BGC was on-site for construction of all reclamation measures undertaken at the tailings disposal area, including the surface reclamation covers and a PMF (Probable Maximum Flood) spillway. The spillway was constructed to transfer water off the surface of the cover. BGC’s functions included implementation of a QA/QC program, monitoring and documentation of daily construction activities on behalf of the owner and reviewing any design modifications required during the construction process.
- BGC also developed and implemented a performance monitoring program for the reclamation measures undertaken at the tailings disposal area. The performance monitoring program is on-going and involves collection and interpretation of geothermal and piezometric monitoring data to assess the effectiveness of the reclamation measures.