Precious metals miner Hochschild said that 27 workers were killed and 13 injured in a road accident on Friday morning.
A bus operated by a contractor was carrying workers from the Pallancata operation to the city of Arequipa in southern Peru when the accident happened.
"We are all devastated by this news and we have already started a thorough investigation. However, our immediate priorities are to support those involved in the accident and their families and to work together with the relevant authorities,” said CEO Ignacio Bustamante.