The Project is located in the Hunter Coalfield in the northern part of the Permo-Triassic Sydney Basin, which forms the southern portion of the Sydney-Gunnedah-Bowen Basin (DMR, 1988).

The Wittingham Coal Measures occur widely within the Hunter Coalfield and contain many recoverable seams. The Project targets mining of the Whynot, Woodlands Hill, Arrowfield and Bowfield Seams.

The target seams are within the Jerrys Plains Subgroup, forming part of the upper and middle units of the Wittingham Coal Measures.

Above the target seams, the stratigraphy of the area consists of a sequence of sandstone, siltstone and laminate units within the Wittingham Coal Measures.

Geological Features
The target underground mining area sits on the western side of the Muswellbrook Anticline, which is a prominent regional geological feature. The strata in the area (including the coal seams) dip gently, with gradients varying between 3% and 5%.

Geological features identified in the target underground mining area and surrounds include:
• a north-northwest-orientated regional graben structure to the west of the Maxwell Underground;
• a north-east-trending fault located to the south-east of the Maxwell Underground with a throw of approximately 10 m;
• smaller faults within the mining area with throws of between approximately 2 m to 6 m;
• igneous dykes;
• dolerite sills intruded into the Whynot, Arrowfield and B ........

The Maxwell UG Project is an underground mining operation that will produce high-quality coals over a period of approximately 26 years. It involves the extraction of up to 8 million tonnes per annum of ROM coal from four seams within the Wittingham Coal Measures, using the following underground mining methods:
• Underground bord and pillar mining with partial pillar extraction in the Whynot Seam; and
• Underground longwall extraction in the Woodlands Hill Seam, Arrowfield Seam and Bowfield Seam.

Substantial existing infrastructure at the Maxwell Infrastructure site will be utilised for the handling, processing and transportation of coal. This includes the existing CHPP, train loadout facilities and other infrastructure and services including water management infrastructure, administration buildings and workshops.

The underground mining operations for the Project would extract approximately 148 Mt of ROM coal.

The Maxwell Mine will be developed in stages:
Stage 1
- Sales 3.0 to 3.6Mtpa;
- Bord & Pillar production commences in Q1/CY2023. Bord and Pillar mining of the Whynot seam;
- Q1/CY2025 145m longwall commences. Longwall operating in the Woodlands Hill seam.

Stage 2
- Sales 5.5 to 6.5Mtpa;
- Q2/CY2025 300m longwall commences. Longwall operating in the Woodlands Hill seam.

Bord and Pillar Mining Operations
Bord and pillar mining methods (with partial pillar extraction) a ........

- subscription is required.

Underground and surface operations would use a combination of potable and recycled water. Potable water to the Maxwell Infrastructure would continue to be supplied by pipeline from Muswellbrook.

Water used in underground mining operations would be treated water.

Water used in the CHPP would be recycled from the CHPP rejects with any necessary make-up water obtained from mine water storages.

The CHPP make-up water demand is related directly to the rate of ROM coal feed to the CHPP, the amount of coal bypassed around the coal processing plant, and the rate of production and moisture content of CHPP rejects. The estimated make-up demand varies between less than 1 ML/day up to approximately 3.5 ML/day over the life of the Project.