Geology
Regionally, the predominant geological feature is the Sydney Basin, formed via igneous rifting and crustal thinning resulting in the deposition of Permian and Triassic aged sedimentary sequences. Within the UWJV Project area Permian sediments form the Wittingham Coal Measures of the Hunter Coalfields. The coal measures generally plunge in a west to south-westerly direction and outcrop to the east of the Project area near the Hunter River.

The Wittingham Coal Measures comprise the economic coal seams interspersed with overburden and interburden consisting of sandstone, siltstone, tuffaceous mudstone and conglomerate. Quaternary alluvial deposits unconformably top the Permian sediments. These deposits consist of silt, sand and gravel in the alluvial floodplain of the Wollombi Brook. To the east of the Wollombi Brook is a sequence of aeolian sands, known as the Warkworth Sands Formation, that form a thin capping on the underlying Permian bedrock Additionally, the Triassic Narrabeen Group also unconformably overlie the Permian sediments. The Narrabeen Group, which formed from uplift during the Triassic, comprises fluviatile deposits that form the ridges and a high plateau within the Wollemi National Park, west of the Project Area. Surficial weathering, typically present as a thin heterogeneous layer of unconsolidated material overlying fresh bedrock occurs across the project area.

Locally, the predominant stratigraphic units that occur with ........

Mining and coal handling at United Wambo involves conventional open-cut mining methods involving truck and excavator/shovel operations.

United Wambo comprises of mining within two open cut pits - a new open cut coal mine at United, known as the United Open Cut, and the existing open cut operations at Wambo, known as the Wambo Open Cut. Operations at United Wambo occurred in three Phases during 2020 as defined by SSD 7142; Phase 1A, Phase 1B and Phase 2. The new combined open-cut mine is forecast to produce 10 million tonnes of thermal and metallurgical coal annually.

Phase 1A
Phase 1A commenced on the 6th January 2020 involving construction works and development of the United Starter Pit. Extraction of material from the United Starter Pit commenced under Phase 1A in May 2020.

Phase 1A, included the following activities:
• Salvage of Aboriginal artefacts;
• Clearing of vegetation to facilitate construction and mining activities;
• Construction and use of the Construction Infrastructure Areas (CIA);
• Upgrades to the Mine Infrastructure Area (MIA) at Wambo including the construction of a new workshop, fuel farm, administration offices, carpark;
• Construction of water management infrastructure including three mine water dams (U1, U2 and U3), the Northern Clean Water Drain and water pipelines;
• Installation of erosion and sediment controls;
• Construction of the realigned 330kV, 66kV and 11kV power lines;< ........

- subscription is required.

United Wambo has a combined total entitlement of up to 370 ML/year assuming full allocation under the Hunter Unregulated and Alluvial WSP (Lower Wollombi Water Source), and up to 1,306 ML/year high security surface water under the Hunter Regulated WSP (Hunter River). In addition, entitlements held by United Wambo for water take from the Permian groundwater system under the North Coast Fractured and Porous Rock WSP, are 1947 ML/year.