Low-temperature geothermal potential of the flooded Gaspé Mines, Québec, Canada

Abstract

The low-temperature geothermal potential of the flooded Gaspé Mines, near Murdochville, Québec, Canada, has been estimated from a long-term pumping test and numerical groundwater flow modelling. A former mining shaft was used to pump water for 3 weeks at a rate averaging 0.062 m 3/s (3720 L/min). A mean recovery temperature equal to 6.7 °C and a maximum drawdown of 3.63 m were observed during this test. The observed drawdown was reproduced with a three-dimensional finite element model that simulates groundwater flow through the mine workings and surrounding rock mass. The model was then used to simulate longer-term pumping performed for heat recovery. Modelling results combined with a simplified energy balance calculation suggest that a sustainable energy extraction rate is attained at a pumping rate of 0.049 m 3/s (2940 L/min), with a corresponding geothermal energy production potential of 765 kW, assuming a return water temperature of 3 °C. This energy could be extracted with heat pumps and used for space heating at the town's industrial park.