The coal resource at the DCM is located within the Permian aged Gloucester Basin in NSW. The DCM is located in the southern closure of the main synclinal structure of the Gloucester Basin and is associated with the coal bearing strata of the Dewrang Group. The Dewrang Group comprises three main stratigraphic units, namely: Mammy Johnsons Formation; Weismantels Formation; and Duralie Road Formation.

The coal seams mined at the DCM include:
• the Weismantel Seams;
• the Clareval Seams; and
• the Cheerup Seams.

The underlying basement rocks are principally volcanics of Early Permian (i.e. Alum Mountain Volcanics) and Carboniferous age that were folded during formation of the Gloucester Basin. The Early Permian and Carboniferous volcanic rocks are typically erosion resistant and form the more prominent ridges to the east and west of the DCM.

Coal production commenced at the DCM in 2003 with mining of ROM coal using conventional open pit mining methods.

The DCM operations are supported by on-site facilities including a main infrastructure area, water management infrastructure/storages and rail
infrastructure.

ROM coal is loaded by excavator into haul trucks from the open pit and transported to the coal handling area (including a rotary breaker), at the main infrastructure area.

The Duralie mine produces two ROM products which are processed and blended with other ROM coals at the Stratford CHPP.

Stratford CHPP produces a coking coal and a range
of thermal coal products for export.

The coking coal has excellent coking properties with fluidity, rank, swell and dilatation significantly higher than the majority of coking coal products exported through the Port of Newcastle.