SANTIAGO – Chile's environmental regulator initiated a sanction process against Antofagasta Minerals' Los Pelambres copper mine for deficiencies associated with tailings management, the agency said in a statement released on Wednesday.

The Environmental Superintendent (SMA) filed one minor and two major charges for improper use and deficiencies in emergency tailings pools, as well as deficiencies in the communication protocol for incidents and contingencies.

In a statement, the SMA said the case began due to citizen complaints and made recommendations for managing particulate matter emitted by miners.

"Although there were no breaches when it comes to measurements and standards associated with air quality, improvements that could be implemented in voluntary agreements between the company and communities were observed," the statement said.

In a statement released after the announcement, Antofagasta said corresponding protocols were activated and water measurements were carried out both by an external laboratory and authorities after runoff from a pool was detected in a local community last November.

"All these measurements ruled out alterations in the water quality in the Camisas estuary," the statement said.

The company said it is reviewing the scope of the sanctioning process to determine its next steps.

Serious infractions could mean a loss of the mine's environmental permit, closure, or a fine. Minor infractions can result in a written warning or a fine. In this case, the maximum fine could reach 7.5-billion Chilean pesos ($9-million).

The firm has 10 business days to submit a Compliance Program detailing how it will improve and 15 business days to formulate its arguments.

This is the third time the mine has faced a sanction process, the first, in 2013, resulted in fines and another in 2016 ended with a compliance program.