Con Mine in 1945. Eric Kettlewell/NWT Archives
Con Mine, the first gold mine in the Northwest Territories, operated between 1938 and 2003. As part of its decommissioning, the underground mine was flooded with water, which – due to its depth – is naturally warmed by geothermal energy, or heat from the sub-surface of the Earth.
The NWT Geological Survey and researchers at Institut National de la Reserche Scientifique in Quebec, are now looking into how much heat is produced and whether it could be extracted for use.
“Geothermal is a renewable resource and it can be exploited continuously, so seven days a week, 24 hours a day,” explained Jasmin Raymond, a professor at the institute. “We could replace a heating system that is based on fossil fuels with a geothermal heat pump system and reduce greenhouse emissions.”
Viktor Terlaky, manager of energy sciences for the NWT Geological Survey, said the research project touches on two of the territorial government’s mandates: to diversify the economy and reduce greenhouse gas emissions to 30 percent below 2005 levels by 2030.
“Hopefully it will reduce greenhouse gas emissions and move toward a greening economy,” he said.
This is not the first time researchers have examined Con Mine’s potential as a geothermal heating source. The City of Yellowknife previously commissioned three geothermal energy evaluations of the site with plans to develop a district heating system.
While preliminary studies found geothermal energy from Con Mine could reduce energy costs and greenhouse gas emissions in Yellowknife, each subsequent assessment reduced the amount of heat available. The city ultimately abandoned the plan, saying it was not worth the cost of extracting the heat and developing pipelines to distribute it.
Raymond and Terlaky said the current research uses a different methodology to provide a more accurate resource estimate.
Over the summer, researchers measured water temperatures both in and outside old ventilation shafts at the mine, and examined the thermal and hydraulic properties of rocks. Raymond said that information is being used to develop a digital model simulating the geothermal system.
“The science has come a long way,” Terlaky said, noting that preliminary results suggest higher resource estimates than previous studies.
He added researchers are “not trying to put the cart before the horse,” and instead are focusing on first assessing the geothermal potential before considering any development.
An industrial park has come up as a possibility, Terlaky said, as the mine site is located near Kam Lake, but it’s not the only option. If the final resource assessment is favourable, he said the next step will be to work with the City of Yellowknife and the current owner of the property to start a pilot project to demonstrate the viability of a geothermal heating system.
Geothermal energy has been explored as a renewable energy source elsewhere in the NWT. The Department of Industry, Tourism, and Investment says geothermal potential has been identified in Fort Liard, Fort Providence, Fort Simpson, and Hay River.
A proposed geothermal power plant in Fort Liard fell through in 2013 after Borealis GeoPower, a Calgary-based corporation that was working with the Acho Dene Koe First Nation on the project, failed to reach a power purchasing agreement with the NWT Power Corporation, which was a condition of federal funding.