The Capcoal complex consists of the Capcoal Open Cut and Grasstree, Aquila underground mines, near Middlemount, in Bowen Basin.

The majority of coal of Capcoal (OC) is mined from the German Creek Formation, which contains five coal seam intervals known as the German Creek, Corvus, Tieri, Aquila and Pleiades seams.

The Aquila is planning to extract reserves from the Aquila and Aquila Lower seams, which occur in the upper part of the German Creek formation.

The Grasstree is located on the north-western flank of the Bowen Basin. The Permian coal measures include the Rangal Coal Measures, the Burngrove Formation, the Fort Cooper Coal Measures (also known as the Fairhill Formation), the Macmillan Formation and the German Creek Formation. The coal measures comprise a sedimentary sequence with interbedded coal seams, including the target GC seam. The upper profile of the coal measures has been extensively and deeply weathered. The weathered coal measures outcrop at the surface across the southern portion of the longwall mining area and much of the surrounding area, forming undulating sandy plains. In the northern portion of the longwall mining area, the coal measures sub-crop under the Tertiary sediments and dip to the east. As the coal measures dip to the east, the depth of the GC seam increases from approximately 330 m in the south-western part of the Grasstree longwall mining area to a maximum depth of approximately 540 m at the north-eastern extent of the longwall mining of area.

Capcoal comprises opencast operations at Lake Lindsay and Oak Park, with an underground longwall operation at Grasstree and Aquila.

The Aquila comprises a single longwall underground mine and supporting infrastructure. The operation will target two seams, the Aquila and Aquila Lower coal seams. The depth of the Aquila seams from the surface varies from approximately 70 metres up to 280 metres with a nominal seam height ranging from 1.8 metres to 2.2 metres.

The longwall will be supported by two continuous miner development units with ROM coal transferred from the underground development and longwall mining units via a new underground conveyor belt system to a new surface conveyor and onto an expanded ROM stockpile.

Longwall mining of the Grasstree involves a coal shearer travelling back and forth across the width of the longwall panel, starting from the furthest point progressively removing the coal from the panel back to the main headings The shearer cuts the coal from the coalface on each pass and delivers the coal to a face conveyor that runs along the full width of the longwall. The face conveyor transports the coal from the coalface to another conveyor in an access roadway. Coal is then transported to the surface via a series of connecting underground conveyors.

Longwall mining will be undertaken in the German Creek seam. This is the same seam being currently mined at Grasstree Mine. The longwall panels will be approximately 340 m wide and will range from approximately 2.4 km to 3.3 km long. The extraction height will vary from 2.4 m to 2.6 m. The width of the proposed chain pillars (the coal left between the longwall panels) will be approximately 50 m. The target coal seam in the project longwall mining area is at a depth of between 330 m and 540 m.

Capcoal Operation in Middlemount includes Capcoal Open Cut Mine, Grasstree and Aquila Underground Mines, the Coal Handling and Preparation Plant (CHPP).

Coal from the underground workings the Grasstree Mine is transferred to the surface via the Southern Colliery drift conveyor. The conveyor drift portal is located in the highwall of Pit A. The drift conveyor travels from the portal, up the Pit A ramp, to the Grasstree Run-Of-Mine (ROM) coal stockpile. Coal from the ROM coal stockpile is transferred through a breaker station, where it is sized and coarse rejects are removed. The coal is then loaded onto an overland conveyor for transport to the CHPP. The coarse rejects are trucked from the breaker station and placed in the Pit B open cut void.

ROM coal is washed at the CHPP. Product coal is transported from German Creek mining complex via an onsite rail loop and train loading facility. Product coal is railed to Central Queensland ports, including Dalrymple Bay Coa ........