Musselwhite underground gold mine, located in Northwestern Ontario, started commercial production on April 1, 1997. The Musselwhite mine is owned by Goldcorp. By 2001, Placer Dome had produced one million ounces of gold. With current mineral reserves, Musselwhite has an expected mine life through to 2012.
The mine is a fly-in operation with pickup points in Thunder Bay and five other Northern communities. The mine employs 293 full time employees and has 105 contract personnel providing support services.
Five First Nations communities are located within the vicinity of the mine. The Musselwhite Agreement was signed by First Nations, federal and provincial agencies and Placer Dome prior to mine development.
The mine supports an apprenticeship program that focuses on training First Nation employees. The mine is not unionized. The majority of employees work on a two-week rotation fly-in schedule with 12-hour shifts. Flights are from Thunder Bay and nearby communities.
Gold is the only metal mined at Musselwhite. Gold bearing mineralisation is characteristically hosted in folded oxide-silicate facies banded iron formations. The cash cost of mining is $178 per ounce and the total cost (including equipment use and associated environmental work) is $288 per ounce. The mill processes 3500 tonnes per day. Conventional methods of gravity, cyanidation and carbon-in-leach processing are used for recovering gold that is refined into ore on site. A small open pit was operated to supply the initial mill feed and currently mining is underground by open blasthole stopping methods. All waste rock generated on site is being returned underground for use as rock fill.
Since the start of mining operations, the mine has had two separate incidents of non-compliance in 1997 and 1999 when elevated levels of ammonia were discharged to the Paseminon River. Placer Dome states that these incidents did not have a significant impact on the environment, since an Environmental Impact Assessment (EIA) conducted prior to mine startup determined that ammonia levels could be set much higher than regulatory limits. The same EIA resulted in many parameters in discharge being set lower in the Certificate of Approval than the established regulatory limits.
Significant spills that have occurred on site have been due to human error in operating valves at the mine. All spills have been contained excepting a discharge of water from underground when changing water lines, however, discharge quality of water in this instance was good. The mine has provided contingency planning for spills originating from the mill or the tailings line. Impervious collection ponds are installed for spill control and these are designed to accommodate spills as well as precipitation. It is important to provide monitoring of these contingency facilities to ensure that spills are detected in a timely manner.
Freshwater is taken from Opapimiskan Lake for potable use, for underground use and for mixing with reagents in the mill. Annually the mine uses 576,000 cubic meters of freshwater. The mine discharges significant quantities of water from the tailings impoundment through Snoppy Pond including process water as well as water draining into the impoundment from a relatively large catchment area. Recycling of process water at the mine could be improved and this would reduce discharges from the mine. Freshwater is required in the mill mainly due to problematic levels of suspended solids in process water. The mine should further investigate reuse of process water in this instance, providing a means for settling of suspended solids.
On November 12, 2002, Placer Dome was fined $500,000 for violating the Occupational Health and Safety Act when Rock Lamirande was killed 275 metres below the surface.
Placer Dome had also been charged on November 22, 2000, when a wheel assembly struck two workers. One died, and the other suffered facial fractures and a compound fracture to his left arm. Placer Dome was charged $500,000.