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 surface geology of the Ashton coal leases is dominated by outcrops of the Jerry’s Plains and Vane Subgroups which form the Whittingham Coal Measures. The main rock types of this subgroup include sandstone, siltstone and conglomerate, which occur with subordinate coal and tuffaceous claystone.

The Ashton area is located on the Camberwell Anticline which has a north north-west to north-west orientation and plunges to the north-west. The Camberwell Anticline is asymmetric with a moderately dipping (9° to 18° degrees) eastern limb which is situated in ML1529 and a gently dipping (6° to 9°) western limb which is situated in the remainder of the area. The western limb at Ashton contains the seams that are equivalent to those in the Auckland area at HVO. The Ashton area contains all coal seams from the Bayswater Seam to the Hebden seam which in stratigraphic descending order are:
- Bayswater;
- Lemington;
- Pikes Gully;
- Arties;
- Liddell;
- Barrett; and,
- Hebden.

The coal seams at Ashton exhibit the same degree of seam splitting, seam thickness. The Barrett Seam outcrops on the Camberwell Anticline. The stratigraphically higher coal seams above the Barrett Seam crop out sequentially from east to west throughout the Ashton area.

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.

During 2021 reporting period coal was mined from Longwall (LW) 204 and LW205 within the ULLD seam with road development principally between Panels LW206 and LW207.

The CHPP was commissioned in April 2004 and expanded during 2006/2007, increasing its capacity from 400t/hr to 1 000t/hr. The CHPP continues to process coal from the Ashton underground operations for export through the Port of Newcastle, NSW. The Ashton CHPP consists of two modules. Module 1 was constructed in 2004 however is currently being dismantled. The mine plan is based on using the operating Module 2 which has a throughput capacity of 600 to 800 tpa subject to the nature of the ROM feed. The CHPP includes Dense Media Cyclones, spirals and flotation process which are all industry standard. The plant is currently operating on a 5 day roster, which at the achieved throughput rates provides for sufficient operating time to wash the ROM coal from the underground project which has a peak rate of 3.4Mtpa. To achieve the LOM plan peak production rate of 6Mtpa which includes coal from both the underground and the South East Open Cut, Yancoal propose to operate the plant on a 24/7 ros ........