TORONTO -- The Canadian Red Cross has been called in to help with contact tracing at an iron ore mine that may have played an early role in spreading the highly transmissible Delta coronavirus variant around the country.

Public Safety Minister Bill Blair tweeted Tuesday that the Red Cross will provide remote contact tracing support related to COVID-19 cases at the fly-in Mary River mine until Sunday.

Operated by the Baffinland Iron Mines Corporation and located on the north end of Baffin Island – remote even for Nunavut – Mary River made headlines earlier this year because of local opposition to plans to expand the mine, including a week-long blockade of its access road and airstrip by Inuit hunters.

A few cases of COVID-19 were detected at the mine sporadically through 2020, but the situation escalated last month when what is now known as the Delta variant began to spread there.

An outbreak at the site was confirmed by territorial health officials on May 2. At the time, there were nine active cases of COVID-19 at Mary River among some 1,000 workers.

Although shift changes and other non-essential travel were halted when the outbreak was declared, the case count continued to climb. By May 4, the nine cases had become 12. Two days after that, the number was 23 and non-essential operations at the site were shut down.

That meant a flurry of activity as most of the mine's active workers returned to their homes across the country. Yet it wasn't until more than three weeks later that health authorities in Ontario, Newfoundland and Labrador, and elsewhere began to publicly warn household members and high-risk contacts of those who worked at the mine and tested positive for the virus.

It is difficult to determine exactly how many cases were the result of exposure at the Mary River mine, because Nunavut does not include them in its overall COVID-19 case count.

Instead, individuals who test positive at the mine are counted as COVID-19 cases in their home communities – where they live during the weeks when they are not at the site.

Provincial health authorities in Ontario reported on May 31 that they were aware of more than 120 positive cases in workers who had returned to the province from Mary River, covering 33 of Ontario's 34 health regions. The timespan of mine workers returning to the province closely aligns with that of the Delta variant becoming a serious concern in Ontario, although no direct connection has been proven.

Dr. Michael Patterson, Nunavut's chief public health officer, told reporters on Monday that the last new diagnosis of COVID-19 at Mary River was made on May 29, and that there have not been any active cases there since June 5.

The mine remains in an outbreak situation, however, and the territory reminded mine employees last week that once they leave the site and return home, they must isolate and notify their local public health authority.