SANTIAGO (Reuters) -A workers' union at BHP's Escondida mine in Chile, the world's largest copper mine, in a statement on Wednesday said two recent accidents involving autonomous trucks are raising safety concerns.

The union, which has often been critical of BHP and has staged strikes as part of contract negotiations, said that on August 25 an autonomous truck collided with shovel machinery and the week before, another truck overturned.

It did not report any injuries.

BHP did not immediately respond to a request for comment.

The company in July said it had fully implemented autonomous operations for 33 trucks and eight drills at the mine's Escondida Norte unit, completing a five-year rollout.

"Less than a month since the announcement, the reality is revealing a huge risk to the safety of workers," the statement said.

Escondida produced 1.28 million tons of copper last year.