New discovery at Gahcho Ku mine could be good news for N.W.T., company bottom line

The discovery of a new kimberlite pipe at the Gahcho Ku diamond mine could be good news for Mountain Province Diamonds and De Beers Canada, the co-owners of the mine, and for the Northwest Territories.

The diamond bearing, underground rock named the Wilson kimberlite after Alice Evelyn Wilson, Canada's first female geologist is the first kimberlite discovery at Gahcho Ku in 20 years.

It is too soon to say if the new discovery will prove to be economically viable, but Mountain Province CEO Stuart Brown says drill sample results are promising.

"We still haven't yet fully ascertained the full size of the kimberlite," Brown said. "We have to do a lot more work on it, but it gives us a signal that two things that it's a very prospective area, we are discovering more kimberlite at a mine that's quite mature now, and that shows us the mine will have a potentially longer life which means good things for the Northwest Territories."

After emphasizing the preliminary nature of the results, the company states in a press that the Wilson pipe has a "potential range from 1.5 - 3.0 million tonnes" of ore. The grade per tonne at the mine's three other pipes (5034, Hearne, and Tuzo) ranges from 1.22 carats per tonne to 1.99 carats per tonne.

The deposit is approximately 200 metres away from the Tuzo pipe, and so contained within the existing, fully licensed mine plan. Brown doesn't anticipate any new permitting would be required to process the deposit, which sits under approximately 18 metres of water that would be diked and drained before open-pit mining.

More core sampling and assessment is underway, with new results expected later this year.

"Every miner wants to make their mine last longer than initially thought," Brown added. "It's good for economics."

The Gahcho Ku mine is located at Kennady Lake, approximately 280 kilometres northeast of Yellowknife. The $1.1 billion joint venture project went into commercial production in March, 2017, and is expected to remain in production until 2030. Mountain Province has other diamond exploration projects in the region.