The “geotechnical failure” — or a landslide — occurred on the north wall of the KOV open pit mine, Glencore-owned Katanga said in a statement. It added that all relevant authorities had been informed and that all activity on site had also been suspended.
“We understand that seven persons, who were believed to have been working on the ongoing de-watering of the pit in the vicinity of the failure, are currently unaccounted for,” Glencore said in a separate statement, adding that rescue efforts were ongoing.
The missing workers are believed to have been undertaking maintenance work when the accident happened.
An “unknown amount of damage” to the dewatering infrastructure in the pit also occurred, the company added.
Katanga Mining (TSX:KAT) is 75% owned by Glencore, which suspended all operations in Septemberfor 18 months to invest in new processing facilities and potentially provide a boost to copper prices by reducing a global glut.
At the time, Glencore also said it would continue with the planned investment of $880 million into on-going processing plant upgrades and the waste stripping of the KOV and Mashamba open pits.
These upgrades include the commissioning of the new leach plant, which will replace the existing oxide concentration process.
The efforts are expected to significantly improve both copper recoveries and operating unit costs when processing resumes, Glencore said.