Chile probe blames Lundin Mining for sinkhole

Chilean authorities concluded that Lundin Mining's Ojos del Salado was to blame for a 60m sinkhole that appeared near the company's Alcaparrosa copper mine in Atacama region in late July.

The investigation – carried out by environmental regulator SMA, the general water authority and mining and geological service Sernageomin – found that the miner extracted ore beyond the allowed limits and built infrastructure outside of environmentally approved zones. 

"When the event occurred, large amounts of water began to leak into the mine from places where the company intervened beyond what was considered in the environmental assessment," the head of SMA, Emanuel Ibarra, said in a statement on Thursday.

The infractions are related to changes in the underground drainage system, underground pools and other factors that affected the Copiapó River aquifer, according to SMA documents. The over-extraction at Mina Alcaparrosa also contributed to the sinkhole, the investigation concluded.

The probe also confirmed the use of trucks with a higher tonnage than what is environmentally permitted for the Mina Alcaparrosa operational continuity project, according to the regulator, and modifying the destination of the reception of the ore, which should have been in its entirety at the Candelaria mine site.

Ojos del Salado produces copper concentrates from the Santos and Alcaparrosa underground mines, which are part of the Candelaria mining complex operated and owned (80%) by Lundin, in which Japan's Sumitomo has a 20% stake.

The cylinder-shaped sinkhole appeared after more than 100t earth came loose, about 600m from a populated area called Tierra Amarilla. Local authorities and residents have expressed their concern about mining in the area.

With the formulation of charges, a process is opened that will involve the community and the municipality, and the company will be able to present its defense. After that, a decision will be made and any pertinent sanctions determined, the environmental regulator said.