SANTIAGO, June 25 (Reuters) - Chilean copper miner Antofagasta Plc said on Tuesday it would ask regulators for more time to answer questions about an environmental impact study for its Zaldivar mine, which draws water from Chile's lithium-rich Atacama salt flat.
Chilean regulators last year delayed their review of Zaldivar's environmental study amid rising concerns over dwindling water supplies at Atacama. Regulators recently reopened the process.
Antofagasta said in a statement it planned to seek a further extension to give it time to "receive all the observations submitted by the public ... and allow us to respond to them."
The Atacama salt flat is home to lithium miners SQM and Albemarle Corp, which together produce one-third of the world's supply of the ultralight battery metal. Atacama's aquifers are also a key water supply for BHP's Escondida copper mine, the world's largest.
Antofagasta, which co-owns Zaldivar with Barrick Gold Corp , said the extension would give it time to consider a proposal from neighboring Escondida to share information on the availability of water beneath the flat.
BHP Group Ltd is also seeking environmental approvals to draw water from Atacama.
Antofagasta said in the statement it had chosen to draw less than half the water it was currently authorized in order to "contribute to the sustainability of the watershed."
The company said it held permits to draw 500 liters (132 gallons) per second from aquifers beneath the salt flat but that it had opted to draw no more than its current rate of 212 liters (56 gallons) per second.
Water is a touchy subject at Atacama.
A preliminary study from 2018 on water at Atacama found more water was leaving the system through pumping and evaporation than was coming back via rain and snowfall, sparking concerns among indigenous communities and environmentalists.
A more comprehensive water study is expected by year's end. (Reporting by Dave Sherwood and Fabian Cambero; Editing by Peter Cooney)