A new mining approval process that could give greater consideration to environmental concerns and potentially threaten the expansion of a Rio Tinto coal mine could be on its way to New South Wales.

Reuters reported that New South Wales Planning Minister Rob Stokes said in a statement that he wanted to alter the mining approval policy in the country's biggest state to reflect “careful deliberation of environmental, economic and social issues,” shifting away from prioritizing the extraction of resources.

The proposed change could affect Rio Tinto’s planned expansion of its Mount Thorley Warkworth coal mine about 120 miles north of Sydney, which is awaiting final clearance after an approval process that has taken several years.

Rio Tinto Coal Australia managing director Chris Salisbury said the miner had already made extensive changes to its plans to accommodate community concerns.

“Regardless of these (proposed rule) changes, we believe there is a clear and compelling case to allow mining to continue at Mount Thorley Warkworth,” Salisbury said in a statement, adding that the extension would add A$1.5 billion ($1.1 billion) to the state economy via wages, royalties and taxes.

The NSW Minerals Council said in a statement that the government had chosen “what it believes is the easy political option rather than the sound policy option.”

New South Wales is already typically viewed as the toughest state to get mining approvals, as it outsources the process to an independent commission.