Kimberlite discovery at Gahcho Kué Mine

Mountain Province Diamonds Inc. July 11 announced the discovery of a new kimberlite roughly 200 meters east of the planned open pit mining area for the Tuzo kimberlite on the Gahcho Kué Mine property in Northwest Territories.

Named after Alice Evelyn Wilson (1881-1964), who is officially recognized as Canada's first female geologist, Wilson is the first kimberlite discovered on Mountain Province (49 percent) and De Beers Canada's (51 percent) Gahcho Kué joint venture property in more than 20 years.

"The discovery of Wilson demonstrates the high exploration potential of the Gahcho Kué JV area, and after a 20-year discovery hiatus, it confirms that we are on track for discovering new kimberlites in this region," said Mountain Province Diamonds President and CEO Stuart Brown. "This discovery also heightens our focus on the potential for more discoveries in the corridor between the Gahcho Kué JV and the Kelvin-Faraday kimberlites."

The Wilson kimberlite was discovered during an exploration drilling program that was designed to test geophysical and historical drilling anomalies in the area surrounding the Gahcho Kué kimberlites.

The Wilson discovery hole, MPV-19-496C, tapped kimberlite beneath 18 meters of lake water and bottom sediments.

This hole cut roughly 119 meters of tuffisitic kimberlite, fragmental rocks which dominate the steep sided diatreme zones or conduits of kimberlite pipes, and about 55 meters of hypabyssal kimberlite, which is emplaced at medium to shallow depths, from a depth of 152 meters.

Mountain Province said these divisions are preliminary and detailed logging of the core that is currently underway is expected to identify more complex internal lithologies.

The 18 holes drilled at Wilson so far show no connection to nearby Tuzo. Mountain Province said 3D modeling of the drill results suggest that Wilson is elongated north-south and has roughly vertical contacts with country rock along its length. A greater volume of kimberlite is present to the north, and the kimberlite also remains open in that direction.

After logging of the discovery hole, 115.2 kilograms of kimberlite was sent to a lab for microdiamond analysis. A total of 480 diamonds larger than 0.075 millimeters were recovered. The largest stone being a 0.28 carat colorless octahedral aggregate.

Mountain Province said the drilling and microdiamond data for the Wilson kimberlite are not sufficient to define a mineral resource, and the Wilson kimberlite is considered a target for further exploration. Based on drilling and 3D modeling, however, the company estimates a potential range from 1.5 million to 3 million metric tons of kimberlite is possible for the Wilson.

"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 Kué," said Mountain Province Diamonds Vice President of Exploration Tom McCandless. "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."

Additional sampling of core from Wilson for microdiamond and geological assessment is presently underway. Further drilling to delineate the northern extent of the Wilson kimberlite is also in the planning stage, with the interpretation of all new results expected later in 2019.

Mountain Province also announced the completion of the winter 2019 exploration program at Kennady North, a property it owns immediately adjacent to Gahcho Kué.

The objectives of the winter program were to remove heavy equipment from previous bulk sampling programs, and to drill exploration targets situated 3,000 to 4,000 meters southwest of the Gahcho Kué Mine.

The first objective was successfully completed but the drilling was hindered by flight-restrictive weather for the helicopter-supported drill program. Only five holes totaling 917 meters of the 2,000-meter program were completed and no kimberlite was intersected.

Mountain Province said the untested targets will be reviewed for discovery potential and reprioritized along with other targets in the Kelvin-Faraday Corridor located northeast of Gahcho Kué.

–SHANE LASLEY