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 within the Project area and nearby surround, include:
1. Quaternary sediments
- Localised presence along North Wambo Creek, 4-7 metres thick comprised of clays, sandy silts, with localised occurrence of medium grained sand.
- Along Wollombi Brook and the Hunter River flood plans – commonly comprises two distinct depositional units, the surficial alluvium and productive basal alluvium. Typically constrained to within 400 metres of the creeks and is between 7 – 19 metres thick.

2. Triassic Narrabeen Group
- Comprises quartz-lithic to quartzose sandstone, conglomerate, mudstone and siltstone with rare coal. Does not occur within the project area but 500 metres west

3. Permian Newcastle Coal Measures
- Formally known as the Wollombi Coal Measures, present in the south-west of the Project area. Generally less than 15 metres thick and deeply weathered comprised of tuffaceous claystone, tuff, siltstone, sandstone, conglomerate, and minor coal. Coal within the Newcastle Coal Measures generally contains stone and is not considered of economic quality within the region

4. Permian Wittingham Coal Measures.
- comprise coal seams interbedded with siltstone, sandstone and shale (known as the interburden) and up to 450m thick at the Project Area.

The Wittingham Coal Measures outcrop approximately 8km to the north and east of the Project area where recharge via rainfall infiltration occurs. The coal seams also subcrop in localised zones along the Hunter River and Wollombi Brook, where they are recharged by the overlying alluvium. Recharge also occurs via leakage from the overlying Triassic Narrabeen Group. The coal measures form unconfined groundwater systems at outcrop, becoming confined as they dip towards the south-west.

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;
• Development of the United open cut starter pit including the blasting of material;
• Construction of mine haul roads and access roads from mine spoil won from the starter pit; and
• Installation of lighting to allow 24/7 operations.

Phase 1B
Mining operations commenced under Phase 1B of SSD 7142 on 20 July 2020. Phase 1B, which included the following activities:
• Continuation of Phase 1A activities; and
• Commencement of mining operations at United, including the emplacement of overburden into the emplacement areas and the stockpiling of ROM coal at the RL106 stockpile.

Phase 2
Phase 2 of SSD 7142 commenced on the 1 December 2020, with activities within both the United Open Cut and the Wambo Open Cut undertaken by the United Wambo Joint Venture, managed by Glencore.

Mining at Wambo Open Cut continued within the Montrose Pit, with development of access to the Montrose Ridge being undertaken late in 2020.

Mining continued within the United Open Cut, with continued development of the United Starter Pit and the main United Open Cut box cut in late 2020. Development of the emplacement areas within the RL106 dump continued. During Phase 2, coal mined from both the United and Wambo pits was transported to the main ROM Stockpile.

United Wambo Joint Venture (UWJV) open-cut mine commenced operation in January 2020. The mine integrates existing open-cut operations at the Wambo coal mine with a new open-cut mine at the adjacent United coal mine.

Operations at United Wambo occurred in three Phases during 2020; Phase 1A, Phase 1B and Phase 2.

During Phase 1A and 1B, no coal produced from the United Open Cut was processed by the Wambo CHPP.

During Phase 2, ROM coal mined in the United and Wambo Open Cuts is hauled to the ROM pad located near the Wambo CHPP. Coal hauled to the ROM pad can be placed directly into the ROM bin or placed onto the main ROM coal stockpile. ROM coal is crushed and washed at the Wambo CHPP and a product coal stockpile is used to stockpile product coal, prior to reclaim and loading to trains for transport off site.

The run-of-the-mine (ROM) coal will be transported to the existing coal handling and preparation plant (CHPP) at the site. The existing co ........