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 normal faults.

Fifty-one faults have been interpreted at the Bulli Seam Operation area to a level of confidence that allows them to be incorporated in the geological model. The throw on the Appin faults average approximately 20 m, although the maximum throw is 90 m; approximately 13 faults have throws of greater than 5 m. As the average thickness of the Bulli Seam is less than 2.7 m, a throw of more than 2 to 3 m can adversely impact the potential for eventual economic extraction. This was demonstrated at West Cliff (now Appin North) where LW 22 to 24 were constrained due to faulting. The Appin mine plan has been laid out to avoid the significant faulting identified by exploration to date.

The Bulli Seam Operation has igneous dykes varying from near vertical and thin (less than 0.3 m), which are boggy and soft and easy to mine, to more significant dykes of 4 to 5 m in width which are very hard (up to UCS of 270 MPa) and more difficult to mine. Through geological studies and operating experience, the igneous dykes are understood and have been observed to have narrow contact margins. Hard and wide dykes are being intercepted in the current mining area.

Appin Mine underground longwall mining operations have transitioned wholly to Appin Areas 7 and 9 following completion of longwall mining activities at Appin North (West Cliff Area 5) in early 2016. Appin North (West Cliff) merged with Appin Mine in February 2016.

Appin Mine extracts coal from the Bulli Seam. Appin Mine underground longwall mining operations are accessed from three surface locations: Appin North, Appin West and Appin East.

Mineral processing facilities include the West Cliff Coal Preparation Plant (CPP), the West Cliff Emplacement Area and the Dendrobium CPP (located at the Port Kembla Steelworks). The majority of ROM coal from Appin Mine is directed to the West Cliff CPP for processing. The Emplacement Area is used to emplace coal wash from the West Cliff CPP and Dendrobium CPP.

ROM Coal is transported to West Cliff CPP by:
• Coal trucks from the Appin East (Central) site, along Appin and Wedderburn Roads.
• Bulk coal winder at Westcliff (Appin North) transported underground from Appin Area 7 and 9.

ROM coal from Appin Mine is also transported to the Dendrobium CPP via Mt Ousley on an ‘as required’ basis to maintain work continuity and maintain reduced stockpile sizes at the Appin sites.

Clean coal from the West Cliff CPP is trucked to BlueScope Steel (Port Kembla Steel Works) coal handling facilities or to the Port Kembla Coal Terminal (PKCT) for distributio ........