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 Project areas, including the Permian Shoalhaven Group, Illawarra Coal Measures and the overlying Triassic Narrabeen Group and Hawkesbury Sandstone.

The economic coal seams relevant to the Project areas are hosted within the Illawarra Coal Measures. The general description of the most relevant units is provided below:

* 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 BSO (Bulli Seam Operation (West Cliff and Appin)). 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 and also south west of Appin. Overall, the coal thickness for the Bulli Seam is generally consistent across BSO in the mined out areas and planned areas of longwall mining;

* The Loddon Sandstone is generally between 7 m to 10 m thick;

* Balgownie Coal consists of high ash coal and carbonaceous shale and is generally less than 1 m thick;

* Lawrence Sandstone is 7 m to 11 m thick;

* Cape Horn Coal is a carbonaceous shale to bright coal, typically less than 0.5 m thick;

* Eckersley Formation consists of thin coals, minor carbonaceous shale, laminites and black shales;

* Wongawilli Coal ranges between 7 to 11 m thick and consists of inter-banded tuffs, carbonaceous shales and coal. The basal 4 m contains coal of economic potential and is currently mined at the Dendrobium Mine. The Wongawilli Coal is subdivided into 13 individual plies and 12 partings units and into three working sections as shown in Figure 4-3. The working sections are based on mining experience and are the most relevant division of the seam. The Second Machine Band working section is generally the target of mining at Dendrobium.

* Wongawilli Seam is present within the Appin and West Cliff areas, although a viable working section is not interpreted to occur in the area;

* American Creek Seam is a thin coal inter-bedded with carbonaceous claystone, and,

* Tongarra Coal is a thin coal inter-bedded with carbonaceous siltstone and claystone.

The structure over the Project area is relatively well defined based on the geological data available. Seam dips over the Project area are generally low (1° to 3°). There are localised variations in seam structures. Relatively steeply dipping strata occurring at the Dendrobium Mine between Areas 2 and 3 where dips reach 7° - 8° in an area associated with a small scale fault. The localised steeper dip zones are also often associated with underlying igneous intrusions and domes.

Faulting has been identified across the BSO and Dendrobium Operation. 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, although low angle thrust faults have also been identified (such as Maingate 12 at Dendrobium).

Faulting affects the BSO area more significantly than at the Dendrobium Operation. Fifty-one faults have been interpreted at the BSO 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 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 underground longwall mining operations have transitioned wholly to the Appin areas (Area 9 and Area 7) following completion of longwall mining activities at West Cliff in early 2016. West Cliff/Appin North merged with Appin Mine in February 2016.

The coal seams are extracted via conventional retreat longwall methods with a single longwall currently operating in each mine.

All coal produced at the BSO is processed at the West Cliff Coal Preparation Plant, which incorporates:
* Dense medium drum;
* Primary dense medium cyclone (“DMC”);
* Secondary DMC;
* Froth flotation cells;
* Thickening cyclone; and,
* Horizontal belt filters.

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 directed to the Dendrobium CPP on an ‘as required’ basis to maintain work continuity and maintain reduced stockpile sizes at the Appin Site. ROM coal is transported via Mt Ousley to the Dendrobium CPP (located within the BlueScope Steel complex). 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 for distribution.