LONDON – Dominion Diamond CEO Patrick Evans has left the company, marking at least the third high-profile departure in less than a year at the Canadian miner, which is owned by billionaire Dennis Washington.

Evans confirmed that he departed on December 5. Shane Durgin, who was COO, took over as CEO effective December 7, Evans said in a telephone interview Sunday. Evans said he plans to stay on as an adviser until the end of 2019. He declined to comment further.

Evans was appointed CEO of Dominion in November 2017 after the company was bought by Washington for $1.2-billion. CFO Matthew Quinlan left the miner a month later and Dominion confirmed in September that its former COO, Chantal Lavoie, had resigned. Other senior personnel including Cara Allaway and Elliot Holland have also left this year, according to their LinkedIn profiles.

Evans’ departure was confirmed in an internal memo to staff signed by Larry Simkins, president of Missoula, Montana-based Washington Cos, a copy of which was seen by Bloomberg. Evans joined the company last year “to oversee and ensure a smooth transition following the acquisition of Dominion Diamond Mines by Washington,” the memo said.

A spokesperson for Washington Cos wasn’t immediately available for comment before the start of regular business hours.

Dominion has stakes in two diamond mines, both in Canada’s Northwest Territories. It holds a controlling interest in Ekati, the country’s first diamond mine, and a 40% stake in the nearby Diavik mine, which is operated by joint venture partner Rio Tinto Group.

The area is home to some of the richest but most remote deposits in the world. Ekati has been producing for almost two decades and is nearing its end of life. Studies are under way for two potential expansions that could extend production, but the industry is under pressure from weak prices, especially for smaller and lower quality stones.

There are currently only three operating diamond mines in the region, the third being Gahcho Kue, a joint venture with De Beers Canada and Mountain Province Diamonds. Evans left Mountain Province, where he was CEO for more than a decade, in June 2017 in what the company said was a “mutual decision".