The project area is located within the Hunter Coalfields of the Sydney Basin and includes coal resources and reserves that occur within the Foybrook Formation. This formation is part of the Vane Subgroup of the Whittingham Coal Measures and is the basal coal bearing sequence of the Singleton Supergroup. The areas to be mined are located on the western and north-eastern limbs of the Camberwell Anticline.

The major coal seams identified in the Project Area are, in descending stratigraphic order, the Lemington, Pikes Gully, Arties, Upper Liddell, Middle Liddell, Upper Lower Liddell, Lower Lower Liddell, Upper Barrett and Lower Barrett seams. These seams occur in the lower 180m of the Foybrook Formation. In the eastern part of the project area, the sequence has been progressively eroded until at the eastern boundary only the bottom 100m or so has been preserved.

The strata within the Foybrook Formation comprises in order of predominance, fine to coarse grained sandstone, siltstone, conglomerate, mudstone, shale and coal. The top of the formation corresponds with the base of the overlying Bulga Formation which in turn is overlain by the Archerfield Sandstone and Jerrys Plains Sub group respectively. The latter includes the Bayswater Seam that has been mined in the adjacent Ravensworth development. Only a remnant portion of the Bayswater seam exists in the far western part the project area. In situ coal attributed to this seam does not form part of this development.

ACOL (Ashton Coal Operations Pty Limited) intends to continue mining operations at Ashton Underground, extracting coal from the Upper Liddell (ULD), Upper Lower Liddell (ULLD) and Lower Barrett (LB) coal seams via a descending longwall arrangement. The mine plan has been designed to minimise surface subsidence effects on overlying natural and built features, as far as practically possible. This includes the diversion of Bowmans Creek and adherence to a 40 m horizontal setback between the high bank of the creek (in its diverted form) and the projected vertical edge of the longwall void.

The ACP ( Ashton Coal Project) underground mine operates seven days a week, 24 hours a day on a rotating shift basis. At present, the ACP’s mining schedule in the underground mining area is subject to subordinate approvals and production rates. At the commencement date of this MOP, extraction of LW 201 (ULLD Seam) has been completed and extraction of LW 202 (ULLD Seam) is underway.

Mine Development and Sequence.
Underground mining during the MOP term intends to recover coal reserves from remaining panels of the ULD Seam and the ULLD Seam. The panels are to be progressively mined using longwall mining methods. The main headings are aligned parallel to the New England Highway with longwall panels aligned parallel to the eastern boundary of ML 1533, extending from the New England Highway in the north to the Hunter River in the south. The western limit of mining is defined by the western limit of ML 1533.

It is planned to continue operations with extraction of the ULD, ULLD and LB Seams.

Mining within the PG Seam, LW 101 – 106A of the ULD Seam and LW 201 of the ULLD Seam was completed prior to the preparation of this MOP. Mining within LW 202 of the ULLD Seam has commenced. During the current MOP period, mining will continue throughout LW 202 – 208 of the ULLD Seam, LW 106B – 107B of the ULD Seam, and may begin in LW 301 of the LB Seam.

Mining Method.
The Underground Mine utilises the longwall method of coal extraction, following continuous miner development of main headings and twin heading gateroads.

Seam thickness varies from about 1.8 m to 2.8 m high. All underground roadways will be driven at approximately 2.6 m mined height. The longwall has been designed to allow extraction of the full seam thickness.

The current mining equipment will continue to be used. In general, changes may occur due to replacement or as technology changes.

Three portals provide access and services to the underground mine, these are positioned in the highwall of the Arties Pit, which is located on the north side of the New England Highway. One portal provides access for men and materials, a second access for the main coal conveyor used to remove raw coal form the underground, and the third is currently used for ventilation.

The main headings are located in the vicinity of the New England Highway and consist of five roadways at 25 m centres, however, this is reduced to four and three headings at LW 7 and 8 respectively.

Gateroads in the upper seams are driven as two headings at 30 m centres, with cut-throughs at 150 m centres and are superimposed on each other. These dimensions may need to be reassessed for the lower seams.

LW panels in the ULD Seam are generally offset 60 m to the west of the overlying PG Seam longwall blocks to mitigate the impacts of surface subsidence. The ULD LW blocks are designed with some variation in the vicinity of Bowmans Creek to mitigate surface subsidence effects on Bowmans Creek, in its diverted form. The ULLD Seam LW blocks are positioned directly below the PG Seam layout and are therefore offset 60 m to the east of the ULD Seam LW blocks.

The Coal Handling and Preparation Plant (CHPP) is located in the north-western corner of the project. It initially comprised a 400 tonnes per hour (tph) dense medium cyclone plant with spirals, together with ROM coal and Product coal stockpiling facilities.

The CHPP operates 24 hours per day, seven days per week. The CHPP produces high quality semi- soft coal for use in the steel manufacturing industry and thermal coal for use in power generation.

Coal is loaded onto trains at a dedicated rail siding and transported to the Port of Newcastle for export on the international market.