BHP has started the process to seek approval for extending the operational life of the Mount Arthur coal mine near Muswellbrook to 2045.
The open-cut mine's existing approval expires on June 30, 2026.
The mine, which employs 2000 people, produces thermal coal for both the domestic and export markets.
BHP announced in August last year that it was assessing options to divest from its thermal coal assets, including Mt Arthur, so it could focus on higher quality metallurgical coals.
The company confirmed this week that Mt Arthur's ownership may change in coming years.
The mining extension proposes to extend the mine further to the west of Muswellbrook but does not require changes to existing approved hours of operation or coal transportation, including rail movements.
It will also involve the progressive rehabilitation of landforms consistent with the geofluvial design.
The project is expected to provide continued employment of up to 2,600 people
Mt Arthur Coal general manager Adam Lancey said the process of securing new approvals could take several years.
"Starting now will enable comprehensive assessment, review and stakeholder engagement to take place and provide clarity for the local people, communities and businesses who live and work with Mt Arthur Coal," he said.
Mr Lancey said Mt Arthur Coal owned land that supported other important local industries.
"For many years the mine has co-existed with dairy and wagyu cattle farms, horse studs, olive farms and vineyards and will continue operating side by side with these industries to support local jobs and the economy," he said.
The approval process will require BHP to secure approvals under the State Significant Development and Commonwealth Environment Protection and Biodiversity Conservation Acts, as well as obtain a new mining lease.
The Newcastle Herald on Thursday reported an Australia Institute analysis that showed proposals for new Upper Hunter coal projects have a combined output of 98 million tonnes a year, the equivalent of 10 new Adani-sized coal mines.
In NSW there are proposals for 23 new mines in addition to extension applications for existing projects. If approved the projects would have a combined annual production of more than 155 million tonnes, or the equivalent of 15 new Adani-sized mines.
