It said two people who worked for its mining contractor were fatally injured in a "high voltage accident" while performing maintenance on a haul truck.

The company said La Colorada was temporarily suspended following the incident on Friday but had resumed normal operations on Saturday.

Argonaut and its mining contractor were fully cooperating with an investigation led by the labour department, the company said.

"Our prayers and condolences are with the families of the individuals and the employees and contractors at La Colorada," president and CEO Pete Dougherty said.

"The health and safety of our workforce remains our number one priority."

Argonaut had set a new company safety record in 2018, operating the entire year without a lost time injury at La Colorada and reducing the company's accident rate frequency by 34% compared with 2017, with zero major incidents or fatalities.

La Colorada produced 12,196 gold-equivalent ounces in the June quarter, compared with 28,017oz Au-eq from Argonaut's El Castillo complex in Durango state.

Argonaut shares last traded at C$2.12, a midpoint in its 52-week range of $1.18-$2.87, capitalising it at $380.5 million (US$288 million).