Illawarra Coal's assets are located in the southern portion of the Sydney Basin within the Southern Coalfield.

The full sequence of Triassic to Permian sedimentary units are present within the Illawarra Coal's areas, including the Permian Shoalhaven Group, Illawarra Coal Measures and the overlying Triassic Narrabeen Group and Hawkesbury Sandstone.

Bulli Coal is the uppermost coal unit in the Illawarra Coal Measures. It is extensively worked in the northern portions of the Southern Coalfield. The Bulli Seam is the main economic coal seam for the Bulli Seam Operation - Appin mine and West Cliff Colliery (now Appin North). It averages approximately 2.6 m thick across Appin, gaining a maximum thickness of approximately 4.1 m. The Bulli Seam thins to approximately 1.4 m in the south eastern part of West Cliff (now Appin North) and also south west of Appin. Overall, the coal thickness for the Bulli Seam is generally consistent across Bulli Seam Operation in the mined out areas and planned areas of longwall mining;

The structure over the Illawarra operation area is relatively well defined based on the geological data available. Seam dips over the area are generally low (1° to 3°).

The faults have been identified by 3D seismic, 2D seismic, underground mapping, underground drilling, de-gassing intra-seam holes and, to a lesser extent, interpreted from floor contours generated from drill-hole data. The faults are predominately extension norm ........

Appin Mine underground longwall mining operations have transitioned wholly to AA7 and AA9 following completion of longwall mining activities at Appin North (West Cliff Area 5) in early 2016. Appin Mine extracts coal from the Bulli Seam within the Southern Coalfield.

Appin Mine underground longwall mining operations are accessed from three surface locations: Appin North, Appin West and Appin East.

Longwall (LW) 708B commenced mining on 24 April 2020 and had retreated 2260 m, to finish on 3 January 2022. LW709 commenced on 22 February 2022 and as of the end of the reporting period had retreated 601 m with an estimated completion in July 2023.

Extraction of LW904 commenced on 20 May 2021 and had retreated approximately 2026 m as of the end of June. LW904 was completed 9 August 2022.

Ore and Product Stockpiles
No coal is stockpiled at Appin West, as ROM coal is transported underground to Appin East or the West Cliff Coal Preparation Plant (WCCPP). The Appin West coal storage bins are currently under care and maintenance.

Appin East has a total raw coal stockpiling capacity of up to 50,000 tonnes. The stockpile is recovered with front-end loaders and transferred directly into the coal haulage trucks for transport by road to either the WCCPP or Dendrobium Coal Preparation Plan (DCPP).

Appin North operates six primary coal stockpiles for both clean coal and raw coal.

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