HVO open cut coal mine is jointly operated by Yancoal and Glencore and according to the report the operators are seeking to extend the life of the mine until 2050 and extract an additional 400 million tonnes of coal.

The report prepared by EMM described Hunter Valley Operations (HVO) as a multi-pit open cut mining complex, comprising two mine sites separated by the Hunter River; HVO North and HVO South.

HVO is approximately 24 kilometres north-west of Singleton. While the two mine sites are approved under separate development consents, they are operated as one complex with fully integrated environmental management systems.

The HVO Continuation Project (the Project) comprises the continuation of the life of HVO North and HVO South, from the current approved mining completion dates of 2025 and 2030 respectively, to approximately 2050 at HVO North and 2045 at HVO South.

The continuation of mining across the HVO Complex will optimise resource recovery from the existing operation, predominantly by mining through previously mined areas and to the extent of existing mining tenements, and extracting coal from deeper seams.

The Project will enable the efficient use of existing infrastructure to economically recover an additional 400 Mt of run of mine coal reserves within existing mining tenements and predominately existing approved disturbance footprints across the HVO Complex.

A spokesperson for the HVO said they were proceeding with planning for a proposal that would enable the mining complex to continue to support a workforce of around 1500 and nearly 400 suppliers beyond current approvals.

"The proposal would see mining continue at HVO North and HVO South operations within the existing mining complex," they said.

"As part of this planning process, HVO has submitted referrals to the Federal Government to determine which elements of the project would require determination under the Environment Protection and Biodiversity Conservation Act (1999).

"HVO, a Joint Venture between Yancoal and Glencore, plans to mine existing reserves with no significant increase in the scale or intensity of mining.

"A HVO spokesperson said detailed studies on environmental, social and economic impacts were being prepared as part of the project's Environmental Impact Statement."

The HVO project joins other extension plans for mines in the Upper Hunter with MACH Energy's Mt Pleasant mine near Muswellbrook seeking to nearly double its annual production to 21mt.

This would make it the biggest coal mine in NSW if the project gains approval.

In contrast to these expansion plans BHP announced last week that it would be closing its Mt Arthur open cut mine near Muswellbrook in 2030. The mine was producing 17mta however despite years trying to find a buyer for the site the company made a decision to seek a four year life extension before closure.