The closure of the Donoso dump was until "a definitive solution that permits the adequate drainage of acids generated by the project is implemented," the regulator said in a statement.

Los Bronces, perched high in the Andes near Santiago, produced 436,900 tonnes of red metal in 2014, roughly 7 percent of world No.1 copper producer Chile's overall output. Los Bronces is Anglo's flagship mine in Chile.

The Donoso dump is not in use at the mine and the company does not expect the decision to affect copper production or operations, Anglo American said.

The regulator said Los Bronces, which has been hard hit by water scarcity during a drought in Chile, had committed a number of infractions related to issues with the dump, including one that had caused irreparable damage to surrounding land.

"The situation relating to acid drainage has been in place for over nine years without the company having addressed the issue in the indicated way," the regulator said.

There were also infractions related to forest management, it said.

"The company is analyzing the regulator's decision to decide what course of action to take," Anglo said in response. Anglo said that it was committed to complying with local legislation.

As protests increase against resources projects that communities see as polluting, the Chilean regulator has been showing its teeth, issuing a series of fines for environmental infractions to miners in recent months.

(Reporting by Rosalba O'Brien and Anthony Esposito; Editing by Grant McCool)