The Tarrawonga Coal Mine is located in the Gunnedah Basin, in the Gunnedah Coalfield, which contains sedimentary rocks, including coal measures, of Permian and Triassic age. Regionally, there are two coal-bearing sequences in the Gunnedah Basin, namely:

- Early Permian Bellata Group (comprising the Maules Creek sub-basin and Mullaley subbasin, separated by the Boggabri Ridge);
- Late Permian Black Jack Group.

The Tarrawonga coal resource is located within the Maules Creek sub-basin of the Early Permian Bellata Group. The target coal seams within the Maules Creek sub-basin are contained within the Maules Creek Formation. They subcrop on low hills to the west of theTarrawonga area and dip towards the east.

Target coal seams within the open cut extent are Braymont, Bollol, Creek, Jeralong, Jeralong Lower, Merriown, Merriown Lower, Velyama, Nagero.

Individual coal seams range up to approximately 4.5 m thick, and average 1.5 m. They onlap the Boggabri Ridge to the west of the Tarrawonga area and thicken towards the east.

Sequencing has been developed in order to ensure the efficient mining of coal, minimisation of haul lengths and permit effective overburden emplacement (both out-of- pit and in-pit) to enable the progressive formation of the post mining landform, and reduce the amount of disturbed land at any one time.

The ongoing development of Tarrawonga will involve the sequential clearing of vegetation and removal of soil (land preparation) prior to the removal of overburden and interburden, mining of the identified coal resource and progressive backfilling and rehabilitation of mined-out areas.

During the MOP term, open cut mining will continue eastward within ML 1579, ML 1693, ML1685 and ML1749.

The current truck and shovel mining methods will be utilised for pre-stripping and coal recovery. Excavators will be used to load haul trucks to remove overburden and interburden. Coal will also be loaded into haul trucks with excavators. Additionally, a mobile crusher will operate in a gravel stockpiling area where select overburden will be crushed and screened for subsequent dispatch from site.

Mining operations are permitted to occur 24 hours a day, seven days per week. Coal transport to the Whitehaven CHPP is permitted between 6:00 am and 9:15 pm Monday to Friday, and between 7:00 am and 5:15 pm on Saturdays. No road transport is permitted Sundays or public holidays.

Transport of gravel by truck from Tarrawonga is permitted between 7:00 am and 6:00 pm Monday to Saturday. No road transport is permitted Sundays or public holidays.

ROM coal will be loaded by excavator into haul trucks and transported to the ROM pad and/or temporary in pit ROM coal stockpile areas. At the Whitehaven CHPP, sized ROM coal received from Tarrawonga will be stockpiled in either ROM coal stockpiles for processing in the CHPP or in product stockpiles for bypass loading at the rail loadout facility.

During the MOP term, the majority of ROM coal will be trucked to the ROM pad and ROM stockpiles where it will be transferred to a 40 t hopper and conveyed to the on-site coal crushing and screening facility. ROM coal will then be sized and conveyed to the coal load-out bin for loading in to on-highway haul trucks for transport to the Whitehaven CHPP or Boggabri CHPP for further processing prior to being railed to the Port of Newcastle via the Werris Creek Mungindi Railway for export customers.

Tarrawonga will continue to use an on-site mobile crusher to selectively process domestic specification coal per annum. Sized coal will then be transported via road to domestic customers.

PA 11-0047 permits 3 Mtpa of ROM coal to be transported offsite from Tarrawonga, via approved haulage routes to the Whitehaven CHPP or domestic markets.

Subject to commercial agreement, TCPL and BCPL will handle and process Tarrawonga’s ROM coal at the upgraded Boggabri Infrastructure Facilities and private rail spur. Tarrawonga product coal would also be separately loaded into trains for transport to the Port of Newcastle via the Boggabri private rail spur and Werris Creek - Mungindi Railway.