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.

Austar is a deep underground coal mine. The mine is an aggregate of the former Pelton, Ellalong, Cessnock No 1 (Kalingo) Colliery and Bellbird South Collieries.

During the MOP term, mining will be undertaken within the Bellbird South mining area (longwalls LWB5 to LWB7) using conventional longwall mining methods, and within remaining approved Longwall panels in the Stage 3 mining area (Longwalls A7 to A19) using the Longwall Top Coal Caving (LTCC) mining method.

The LTCC mining method is approved for secondary extraction in the Stage 3 mining area. LTCC mining combines a conventional retreat longwall face with a second armoured face conveyor (AFC) towed behind the shield to recover coal that falls into the goaf. The roof supports are of a modified design incorporating a system of hydraulically operated tail canopies at the rear of the support. The tail canopies can be moved up and down to allow the broken coal in the goaf area to spill onto a second AFC. This process continues until the coal is recovered and waste rock appears. Once waste rock appears, the tail canopies are owered and the AFC pulled forward to stop rock from being loaded onto the conveyor.

Secondary extraction of longwall panels is only undertaken after approval of an Extraction Plan. An Extraction Plan for LWB4 to LWB7 was prepared and approved by DP&E on 20 September 2017. The Extraction Plan was modified to reflect the shortening of longwalls and the modification approved by DPE on 18 September 2018. Secondary extraction from within the Stage 3 area will be undertaken in accordance with existing or future approved Extraction Plans for the relevant area.

Underground Mining is undertaken in two distinct areas: Stage 2 and Bellbird South (covered by Development approval 29/95), and Stage 3 mining area, which includes the underground longwall panels and the Surface Infrastructure Site at Kitchener (covered by Project Approval 08_0111). Approved Mining Operations Plans and Extraction Plans are also required over current mining areas prior to the commencement of mining in each area. These plans are linked below.

Stage 2 mining area covers Longwalls A3 to A5a. These longwalls are located beneath privately held small rural residential properties in Quorrobolong. Modification 2 to approval 29/95(Mod 2) was lodged in September 2007 to enable continued use of LWTCC in Longwalls A3, A4 and A5. Further modifications for the Stage 2 area were lodged to:
- increase void widths and chain pillars in LWA4 and A5 in February 2009 (Mod 3), and
- use LWTCC in Longwall panel LWA5a in July 2010(Mod 4), and lengthen LW A5a by around 127 metres (Mod 5).

Mining in Stage 2 commenced in February 2009 and was completed in January 2013.

Bellbird South LWB1-LWB7 mining area comprises seven longwall panels beneath privately held and Austar owned small rural residential properties in Quorrobolong within the Bellbird South and Ellalong Colliery areas. A modification (Mod 6) to extend the Bellbird South consent area to cover three conventional longwall panels (LWB1-B3), and extend the life of the Bellbird South Consent by 5 years to allow time for extraction was approved on 29 January 2016. A further modification (Mod 7) to permit extraction of four additional longwall panels (LWB4-B7) was approved on 25 August 2017. Longwall extraction commenced in LW B2 in July 2016 and was LW B3 was completed in August 2017.Operations are currently in Longwall B4.

Planning approval PA 08_0111 was granted by the NSW Minister for Planning in September 2009 to permit the extension of mining to the Stage 3 area (Longwalls A7 to A19), east of the Bellbird South operations. There have been three modifications to this approved mining area:

- Modification 1 (Mod 1) was an administrative modification that deleted two words from a condition of consent and was approved in May 2010.
- Modification (Mod 2) sought to reorient the longwall panels and was approved in March 2012.
- Modification 3(Mod 3) was approved in December 2013 to extend the length of Longwalls A7 to A10.

Longwall extraction in Stage 3 commenced in June 2013.

During the next reporting period, longwall mining operations will continue in LWB5 before moving into LWB6 with extraction scheduled for approximately October 2019 to February 2020. At the completion of LWB6, Austar plans to re- establish infrastructure prior to the recommencement of mining in the Stage 3 area.

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.