The company said it was currently managing three cases of COVID-19 among employees, of whom two were asymptomatic.
It said the workplace transmission of the virus occurred in the mill facilities and impacted crews were now self-isolating.
Harte said an incoming crew was set to start its rotation mid-week, with all stockpiled ore to be processed by the end of the month.
"To date, the mining operations have not been impacted by the workplace transmission," the company said.
Strategic review amid forecast cash shortfall
A COVID-19 shutdown in 2020 had stretched the new miner and Harte teed up a US$30 million financing deal to restart Sugar Zone in July last year.
However recent operational monitoring revealed "critical" challenges, with Harte warning in May it did expect to generate sufficient cash from operations to fully fund planned investment activities and debt service obligations, due to the expected lower gold output in 2021.
Harte has reduced guidance by 10,000 ounces to 50,000-55,000oz, which it said would create a revenue shortfall of about C$22 million.
The company initiated a strategic review and said earlier this month it had gained some breathing space by making a short-term amendment to its senior credit facility with BNP Paribas.
Harte shares (TSX: HRT) shares closed at a one-year low of 10c yesterday, valuing it about $105 million (US$85 million).