In Nanaimo, B.C. — a city built on coal — a long-abandoned mine will soon become the heat source for a new university building.

Salt water from the flooded shafts of the Wakesiah mine, which run 135 to 180 metres beneath the Vancouver Island University campus, will be pumped to the surface to extract warmth in a geo-exchange project that has attracted international interest.

“We’re going to…push it in through a heat exchanger and send it back down into the mine.” Alan Cumbers, associate vice-president of facilities and ancillary services for