Austar is located in the South Maitland Coalfield of the Maitland Group which forms part of the Newcastle Coalfields. The mid Permian Age Greta Coal Measures outcrop around the Lochinvar Anticline, which is the dominant structural feature in the Cessnock area. Austar Mine Complex is located on the nose of the Anticline. Coal in the Stage 2 Extension Area will be sourced from the Greta Seam at depths of approximately 530 to 560 metres below the surface.

The Greta Seam is overlain by the Branxton Formation, which comprises a series of interbedded sandstone and siltstone layers up to 20 metres thick. The Pelton Seam, which is less than 0.5 metres thick, lies at the top of the Branxton Formation and forms the upper limit of the Greta Coal Measures.

In February 2020, the Austar mine completed mining of the Bellbird South area and with no immediate economically viable mine plan, was placed on care and maintenance by Watagan. The Yancoal Board has approved commencing mine closure activities at Austar with such activities expected to take between five and ten years to complete.

Austar produces a premium coking coal. It is characterized as the highest fluidity and lowest ash coking coal in Australia with low phosphorous and low alkalies. The seam is typically 4.8 – 6.5 metres thick. Up to 3.6 million tonnes per annum of run of mine (ROM) coal is approved to be mined onsite.

Once mined, coal is sent to the Coal Handling and Preparation Plant for crushing and washing to produce a high quality coking coal product for export. Coal is processed using a combination of dense medium cyclones and spiral techniques, with greater than 92% recovery. The wash plant has the capacity to process 750 tonnes per hour with stockpile capacity of 150,000 tonnes of raw coal and 300,000 tonnes of washed coal.

All ROM coal from the underground is transferred by conveyors via the Ellalong Drift to a 2000 tonne bin at Pit Top, where an overland conveyor system with a nominal capacity of 900 tonnes per hour conveyors the coal to the Pelton CHPP raw coal stockpile. The majority of product coal processed at the CHPP is railed to the Port of Newcastle via the Austar Rail Line, the South Maitland Railway and the Main Northern Rail Line.

The CHPP is a heavy medium (HM) plant. There are three circuits that treat different
fractions:
- No.1 HM circuit treats the -12mm x 1mm coal; and
- No.2 HM circuit treats the - 45mm x 12mm coal.
- Fines circuit treats the -1mm fraction (spirals and cyclones) Coal enters the plant and passes over a set of sizing screens. Oversize material (+120mm) is removed from the plant as refuse and the fines (-1mm coal) are treated in the fine coal circuit.