The company said the accident involved a civil contractor at a surface cement batching plant.

Ivanhoe said the Kamoa-Kakula project had gone more than 7.5 years without a lost-time injury and this was the first fatality.

"We are all deeply saddened by the tragic loss of life at the Kamoa-Kakula project and our thoughts are with the family, friends and co-workers of the deceased at this time," president Tony Giardini said.

"Safety for everyone at our projects is our highest priority."

Ivanhoe said the senior management team was working with DRC authorities to facilitate their investigation of the accident.

Once it was completed, Kamoa-Kakula would "review and implement any additional safety measures recommended to prevent such an accident from recurring".

Kamoa-Kakula is a joint venture between Ivanhoe Mines (39.6%), Zijin Mining Group (39.6%), Crystal River Global Limited (0.8%) and the DRC government (20%).

The US$1.1 billion Kakula development is the first cab off the rank at the large-scale project and it's slated to start copper concentrate production in the third quarter of 2021.

Ivanhoe reported reaching high-grade ore in the underground development earlier this month.

The stage one, 6 million tonne per annum mine and processing complex is expected to be expanded into staged 18Mtpa operation.

Ivanhoe shares closed down C1c yesterday to $3.62, near the middle of its 52-week range of $2.04-$4.54, capitalising it at $4.3 billion (US$3.2 billion).