VANCOUVER -- Health officials have declared an outbreak of COVID-19 at a gold mine in northwest B.C. after nearly two dozen employees and contractors there tested positive for the disease.

At least 22 cases of the coronavirus are associated with the outbreak at the Pretium Resources Brucejack Mine north of Stewart, B.C., according to a news release from Northern Health.

There are approximately 485 employees working at the mine, and proactive COVID-19 testing is underway, the health authority said.

Fourteen of 17 currently active cases are self-isolating at the main Brucejack Mine camp, and anyone identified as a case or a close contact has been instructed to self-isolate either on-site or in their home community, according to Northern Health.

"Northern Health and Brucejack Mine operator Pretium Resources have been monitoring a cluster of COVID-19 cases since early February, and collaborating to implement enhanced control measures for reducing the risk of transmission of illness among mine site employees," the health authority said in its release.

As more cases have been detected, the company has made the decision to shut down worker travel to the main camp until testing of site staff is complete, Northern Health added.