De Beers Group said Wednesday it has determined it's not economically viable to extend the life of its Victor diamond mine in northern Ontario and will be shutting down the operation in early 2019.

The company had previously said it would like to extend the mine's life, and was looking to process low-grade stockpiles and possibly develop a nearby deposit called Tango.

Kim Truter, CEO of De Beers Canada, said the company took a hard look at extending the mine's life but the economics simply didn't stack up.

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"As we worked through the details and really had a look at the economics and our ability to squeeze down costs – which would have had an impact anyway in terms of size of workforce and those sorts of things – no matter which way we spun it we couldn't get the economics to work."

The company had also encountered some challenges in securing support from the local First Nations, but Truter said that didn't have an impact on the final decision.

The mine, which sits about 90 kilometres west of Attawapiskat, currently has about 350 De Beers employees plus about 150 contractors.

Truter said the company will slowly start reducing as they approach the mine closure in the first quarter of 2019.

He said De Beers will work hard to ensure an orderly closure and will look to find new opportunities for those working at the mine, including about 70 to 80 jobs in mine demolition and environmental monitoring.

Some employees might also find work at De Beers' Gahcho Kue diamond mine in the Northwest Territories that it opened last year.

De Beers opened the Victor mine in 2008, where it has produced about seven million carats to date.