1.2.2.1.31 Wilpinjong Coal Mine

Wilpinjong Coal Mine is 40 km north-east of Mudgee in the Western Coalfield. It was bought by Wilpinjong Coal Pty Ltd in 2006, a wholly owned subsidiary of Peabody Energy Australia. The NSW Minister of Planning granted Project Approval 05-0021 under NSW’s Environmental and Assessment Act, 1979 in February 2006. Open-cut mining began in September 2006. Mining is currently undertaken by Wilpinjong Coal Pty Ltd under Mining Lease (ML) 1573 (Peabody Energy, 2014a, p. 1). Operations are planned to continue until 2027 (Peabody Energy, 2014a, p. 2).

The Project Approval for Wilpinjong has undergone six modifications to date. These have included increasing the ROM mining rate from 13 Mt/year to 15 Mt/year in 2010 (MOD3), and then to 16 Mt/year in 2014 (MOD6). Peabody Energy submitted the sixth modification to the Project Approval in 2014 to increase the mining surface area to 800 ha, comprising a 500 ha extension to the existing pit and a new 300 ha pit. The modification also sought approval for a 16 Mt/year mining rate of ROM coal, a 13 Mt/year production rate of thermal coal and the extension of mine life from 21 to 28 years. However, only the increase in the ROM coal mining rate was approved in the 2014 to 2019 Mining Operations Plan (MOP) (Peabody Energy, 2014b, p. 1). The mining operations are undertaken over 1990 ha (including infrastructure) within six open-cut pits using strip mining configuration. Overburden is blasted and pushed to the previous void strip using bulk push dozers. It is then loaded in trucks using hydraulic excavators (Peabody Energy, 2014a, p. 24). The approved rate of waste rock production was increased from 28 million bank cubic metres (Mbcm) to 33.3 Mbcm in February 2014 (MOD5), then up to 34.1 Mbcm in December 2014 (MOD6) (Peabody Energy, 2014a, p. 10). Coal and interburden is sometimes blasted depending on its thickness and hardness, and is then pushed by dozers to the previous strip or hauled in the strip using haul trucks.

Coal is transported by the fleet of trucks on the internal haul roads to the ROM pad. Coal is loaded in the ROM hopper, although some is stored in the stockpile and later dumped in the ROM hopper (Peabody Energy, 2014a, p. 24). Coal is washed in the CHPP with a feed rate of approximately 8.5 Mt/year. The CHPP plant can process 6 Mt/year of saleable thermal coal. With the addition of the 6.5 Mt/year of bypass coal, the approved production rate of saleable coal is up to 12.5 Mt/year since MOD4 approval in 2012. The approved quantity of coal rejects (coarse rejects and tailings) is up to 2.5 Mt/year (Peabody Energy, 2011, p. 5). The coarse rejects are transported with the mining fleet and stored in the waste overburden dumps, while the tailings are transported via pipeline to the open-cut voids (Peabody Energy, 2014a, p. 24).

Coal is loaded at the train loading facility that operates at a rate of 4000 tonnes per hour, then railed east of the mine for the domestic product market or to the Port of Newcastle via the Gulgong–Sandy Hollow Railway. A reverse osmosis plant was installed in 2012 to treat mine water before it is discharged into Wilpinjong Creek (Peabody Energy, 2014a, p. 10). Rehabilitation is ongoing since 2008 in the mine waste rock emplacements and the tailings storage facilities, mainly involving revegetation of disturbed areas. From 2008 to 2013 about 180 ha of land was rehabilitated (Peabody Energy, 2014a, p. 105).