A new deposit of kimberlite — a rock sometimes containing diamonds — has been discovered at Gahcho Kue diamond mine, marking its first major discovery at the site in two decades, a June 11 news release announced.
An exploratory drilling program at the mine discovered the rock, intersecting with the kimberlite below 18 meters of lake water and sediment. The “Wilson” kimberlite find is named after Canada’s first female geologist Alice Evelyn Wilson.
The pipe runs north-south and could be substantial enough to extend the life of the mine. Further drilling is slated to determine the northern extent of the pipe.
Stuart Brown, president and CEO of Mountain Province, said the finding could lead to future discoveries in the area. Mountain Province Diamonds co-owns the mine with De Beers Canada.
“The discovery of Wilson demonstrates the high exploration potential of the Gahcho Kue JV area, and after a 20-year discovery hiatus, it confirms that we are on track for discovering new kimberlites in this region,” Brown stated.
“This discovery also heightens our focus on the potential for more discoveries in the corridor between the Gahcho Kue JV and the Kelvin-Faraday kimberlites.”
The company treated 115.2 kilograms of kimberlite, recovering 480 diamonds sized at .075mm and up, and five .85mm-sized diamonds that weighed .32 carats. According to the news release, the largest rock was a .28 carat. These microdiamonds are too small to be cut, but can provide valuable clues in the exploration for new deposits.
Currently, there are three active pipes at Gahcho Kue: 5034, Hearne and Tuzo.
Located about 200-km from the Tuzo pipe and within the current mine plan, the pipe’s diamond ore could run from 1.5 to 3.0 million tonnes, according to Mountain Province. It also appears to be a distinct pipe, as opposed to a previous kimberlite discovery last year that is connected to Tuzo.
Dr. Tom McCandless, the company’s vice president of exploration, said the the rock was largely dismissed before the new discovery.
“While the results are preliminary, both the microdiamond and 3D modeling data suggest that the Wilson kimberlite will add positively to the mine at Gahcho Kue,” he said. “With this important discovery, what would have formerly been discarded as waste rock has, through methodical exploration, now been converted to rock of value as we move forward with development of the Tuzo open pit.”