Un-mined resources of prime coking coal are primarily in the Bulli and Balgownie Coal Seams under the CamdenCampbelltown-Picton region; however, this is a rapidly growing metropolitan area of Sydney, and subject to strategic land release and other Government policies which limit opportunities for coal resource development.

The Bulli Coal Seam is generally considered to contain prime quality coking coal with medium to high ash and low to medium volatiles, with an average raw coal production rate of 76%. The Project would target the Bulli Coal Seam, which reaches depths of up to 800 m in the central north of the Southern Coalfield and exceeds 850 m in the north-west. The Bulli Coal Seam is 5 m at its thickest in the north of the Coalfield, and in other regions varies in thickness between 2 and 3 m.

Coal is extracted at Tahmoor Coking Coal by a longwall shearer and transported to the surface by a series of conveyors. A schematic diagram of longwall mining is typical at Tahmoor Coking Coal.

The area immediately in front of the coal face is supported by a series of hydraulic roof supports, which temporarily hold up the roof strata and provides a working space for the shearing machinery and the face conveyor. After each slice of coal is removed, the hydraulic roof supports, the face conveyor and the shearing machinery is moved forward.

When coal is extracted using this method, the roof immediately above the seam is allowed to collapse into the void that is left as the face retreats. This void is referred to as the goaf. As the roof collapses into the goaf behind the roof supports, the overlaying strata collapses and may result in subsidence of the surface area above.

Coal extraction of up to 4 million tonnes of Run of Mine (ROM) coal per annum is proposed with up to 43 million tonnes of ROM coal proposed over the life of the Project through Longwall mining. This technique for coal extraction has been used by Tahmoor Mine for over 30 years.

Once the coal has been extracted and brought to the surface, it would be processed at Tahmoor Mine’s existing facilities, before being transported primarily on rail to domestic and international customers.