De Beers applies to expand Gahcho Kué, extend mine life

Last modified: March 18, 2020 at 12:46am

De Beers Canada is applying to expand the predicted size of the NWT’s Gahcho Kué diamond mine after discovering “additional economically viable ore.”

Documents filed with regulators suggest De Beers believes Gahcho Kué’s mine life could be extended by two years, to a total of more than 13 operational years, if the work goes ahead.

How the company’s appetite for the work may be affected by the economic consequences of the growing coronavirus pandemic is unclear.


The paperwork was filed in the first week of March, before many of the current restrictions had been triggered and their global financial impact felt. However, mines usually operate to much longer-term economic schedules.

“In 2019, additional economically viable ore was defined at the north side of 5034 pit,” reads the company’s application to the Mackenzie Valley Land and Water Board, identifying one of three open pits in Gahcho Kué’s current mine plan.

“Incorporation of this ore into the mine plan will require removal of additional mine rock and the deposit of additional processed kimberlite,” the application continues. Kimberlite is a type of rock that contains diamonds.

Getting to the extra diamonds will mean expanding dykes, deepening two open pits, increasing the capacity of a kimberlite containment facility, and finding a home for the extra rock that gets mined.

Gahcho Kué is estimated to remain operational until the second quarter of 2030 under the proposal, with one to two years of “active closure” keeping many employed after that.


Expansion would add two years to the much longer process of trying to return the mine site to some form of natural state. If the expansion happens and the pits are duly enlarged, De Beers expects refilling Kennady Lake – much of which has been dewatered to reach the kimberlite – to take 21 years or more.

The mine is situated 280 km northeast of Yellowknife. It is the newest of the territory’s three working diamond mines, having entered operation in late 2016.

With coronavirus threatening economic oblivion across much of the globe, and the NWT’s economy already stagnant at best, even a hint of improved prospects at Gahcho Kué is likely to be welcomed inside the territorial government.

Documentation filed with the regulator suggests there may, in future, be the chance of further expanding the mine’s pits to reach yet more kimberlite and continue prolonging its life. The mine life could also shrink if De Beers ends up taking less time than planned to extract the necessary rock.


Meanwhile, the company is planning to install a six-megawatt solar farm “with a footprint of about 16 hectares” at the mine.

The expansion requires amendments to De Beers’ land use permit and water licence for the Gahcho Kué site.

On Monday, the Mackenzie Valley Land and Water Board asked for a range of additional information to be submitted within 90 days.

De Beers says the proposed changes will enable the company “to continue our economical and social contributions for the optimum benefit of the local communities and residents. The company claims the expansion “will not cause adverse effects to the biophysical or socio-economic environments.”

The mine is a joint venture between De Beers, which owns 51 percent, and Mountain Province Diamonds.