Gahcho Kué exploring potential for underground expansion

Owners of the Northwest Territories’ Gahcho Kué diamond mine say they are “actively reviewing” the potential of expanding into underground mining.

Gahcho Kué, which opened in 2016 some 280 km northeast of Yellowknife, is currently an open-pit mine expected to begin shutting down in just under a decade’s time.

But drilling results reported this week suggest a “significant discovery” extending away from an existing open pit, according to a news release from Mountain Province Diamonds, which part-owns the mine alongside De Beers in a joint venture.

“As the extension is only in the exposed lower benches of the open pit and plunges to the northwest, an underground operation to recover this ore is a logical pursuit,” Mountain Province president and chief executive Mark Wall was quoted as saying.

“The Gahcho Kué joint venture is actively reviewing underground options for economic recovery of this material.”

The company says a second phase of drilling is now required “to define the volume and depth extent of the Northwest Extension and its economic viability for extraction by underground mining methods.”

While it’s too soon to suggest that Gahcho Kué is committed to any form of underground expansion, discoveries that significantly extend the life of operating NWT diamond mines may be vital to the territory’s economy in the years ahead.

Gahcho Kué and the territory’s two other active diamond mines, Ekati and Diavik, are all expected to cease production in the next decade. Diavik is set to be the first to close in three years’ time.

Ekati has said it is exploring underwater mining to extend its mine life. Gahcho Kué has already extended its planned life at least once.

No future NWT diamond mines are at any significant stage of development, though several smaller ventures into critical minerals have opened or are likely to open soon.