Name of the Mine
Wilpinjong mine.

Location  
About 40 km north-east of Mudgee, in New South Wales, Australia.

Mine Owner/s  
Peabody Energy.

Brief Description  
The Wilpinjong mine is an existing opencut coal mining operation. The mine currently has eight active opencut pit areas, including a new opencut pit in Slate Gully. Overburden is removed by a combination of cast, doze, and truck/excavator methods.

Brief History  
Development of the mine by Wilpinjong Coal Pty Ltd (then a subsidiary of Excel Coal) started in February 2006. Peabody acquired the mine as part of its acquisition of Excel in 2006. Excel started the development of the mine in the same year and production under Peabody ownership in 2007. A third-party contractor managed mining operations until 2013, when Peabody converted the mine to owner-operated.

Primary Metals/Minerals  
Thermal coal.

Secondary Metals/Minerals  
None stated.

Geology/Mineralisation  
The Wilpinjong mine is located in the Permian Illawarra Coal Measures on the north-west margin of the Sydney basin. This coal measure is about 115 m thick in the area, where the dominant lithologies are mudstone, siltstone, sandstone, coal, carbonaceous mudstone and tuffaceous claystone. The coal seams of interest at the mine include the Moolarben and the Ulan seams.

The surface geology of the mine is dominated by subcrops of the Illawarra Coal Measures. This unit overlies the Shoalhaven Group, which crop out immediately south of Wilpinjong. 

The coal measures are overlain by the Narrabeen Group, which forms the cliff-lines and plateaus to the north and south, the ridges that protrude out from these plateaus and outliers such as those adjacent to the Slate Gully area. In places, the Illawarra Coal Measures are concealed beneath younger alluvial deposits, particularly those that occupy abandoned channel-fill, or palaeochannels. Quaternary alluvial deposits also flank the Wilpinjong and Cumbo creeks.

The Moolarben seam comprises three plies, of which the lower half of the basal estimated 0.5-m-thick ply (M4) is currently being mined. The other plies – M1, M2 and M3 – all exceed 40% in ash and have yields of less than 50% and are not considered mining targets. The Moolarben seam has not been mined in the local area in the past.

The Ulan seam ranges between 11 m and 22.5 m in total thickness; however, the mineable coal plies have a combined thickness of 5.7 m to 9 m. The seam comprises several coal and stone plies that are correlated across the Wilpinjong resource area and into adjacent mines and projects. 

The surrounding ridges of resistant Triassic strata have combined with the thick seam and shallow dips resulting in an extensive area of shallow coal that is amenable to opencut mining. These ridges are generally within the national park and are excluded from mining.

Reserves  
The mine had proven and probable reserves estimated at 57-million tons as at December 31, 2023, grading 24.5% ash and 0.5% sulphur content, with a Kcal/kg of 5 431.

Resources  
Measured and indicated resources as at December 31, 2023, were estimated at 128-million tons grading 23.5% ash and 0.5% sulphur content, with a Kcal/kg of 6 020. Inferred resources were estimated at six-million tons grading 27.3% ash and 0.5% sulphur content, with a Kcal/kg of 5 698.

Type of Mine
Opencut.

Mining Method  
The Wilpinjong mine is currently using selective mining and washing, with some bypass to produce domestic and export thermal coal products.

Major Infrastructure/Equipment  
Most of the on-site infrastructure is centralised near the rail loadout loop. The mine also maintains a series of haul roads, light vehicle access roads, communications towers and equipment, and remote ‘ready-lines’ for mobile equipment (including mobile crib huts and light maintenance facilities), as well as water management infrastructure. Explosives storage facilities are also maintained away from the central infrastructure area.

The key supporting infrastructure for Wilpinjong mine includes road access by public roads, port service at two terminals at the Port of Newcastle, above and below rail services, electrical power from a 66 kV transmission line, and water supply from captured surface runoff and deep wells. The mine’s proximity to other large coal producers in the region provides access to a significant pool of experienced mining personnel.

Mining equipment includes excavators (overburden/coal), haul trucks (overburden/coal), dozers, front-end loaders, graders, water trucks, drill rigs, scrapers and a tyre handler.

Prospects  
No updates available.

Contact Details
Peabody Energy 
Tel +1 314 342 3400
Email info@peabodyenergy.com

Sources
Peabody Energy Corporation, website: www.peabodyenergy.com