SANTIAGO (Reuters) - Chilean mining company Antofagasta Minerals (>> Antofagasta plc) has sold its minority stake in a solar park in northern Chile, and will launch a power auction for one of its copper mines, the company said on Tuesday.

The firm said in a statement it had agreed to sell its 40 percent stake in the 69.5-megawatt Javiera solar park in north-central Chile to Atlas Renewable Energy, a Latin America-focused solar platform launched in March by English private equity fund Actis.

Antofagasta participated in the park through EnergiaAndina, a joint venture with Australia's Origin Energy (>> Origin Energy Ltd). Javiera was originally constructed by now-bankrupt SunEdison, and is now 100 percent owned by Atlas (>> Sunedison Inc).

"Atlas is pleased to conclude another important acquisition to grow its footprint in Chile, with long-term contracted projects with high quality offtakers," the company's chief executive, Carlos Barrera, wrote in an email. "We're looking forward to explore further growth opportunities in the region."

Antofagasta did not disclose a price for the sale but said that as part of the transaction, it had renegotiated the prices of the energy produced by the park.

Javiera signed an agreement in 2014 to provide power at a fixed price to Antofagasta's Los Pelambres copper mine. Power prices in the area have since dropped precipitously, meaning the terms of energy contracts inked by large mines in previous years are now largely unfavourable.

"This decision takes place in the context of Antofagasta Minerals reducing costs and focussing on the business that we best know: copper production," Antofagasta CEO Ivan Arriagada said in a statement.

Antofagasta also said it would launch a request for tenders in the coming days to provide energy to its Zaldivar mine in Chile starting in 2020.

The auction is likely to draw interest from an array of domestic and international energy companies that have flooded into the South American nation in recent years.

(Reporting by Gram Slattery; Editing by Peter Cooney)

By Gram Slattery

Stocks treated in this article : Antofagasta plc, Origin Energy Ltd, Sunedison Inc