1.2.2.1.9 Bengalla Coal Mine

Bengalla Coal Mine is owned by Coal and Allied Industries Ltd (Coal and Allied), in turn 80% owned by the Rio Tinto Group (Rio Tinto, 2015a). Bengalla is 4 km south-west of Muswellbrook in the Upper Hunter Valley, and supplies international markets with approximately 7 Mt/year of thermal coal. Development consent was granted by NSW Government for Bengalla in 1996 and the site commenced production in 1999, initially for up to 21 years. On 3 March 2015, consent was granted for the Bengalla Continuation Project, allowing up to 15 Mt/year ROM coal to be extracted at the site until 28 February 2039 (NSW Department of Planning and Environment, 2015b, p. 5).

Bengalla is an open-cut mine, using dragline, truck and shovel methods for extracting coal from around 270 m depth (Hansen Bailey, 2013, p. 68). On-site infrastructure includes a CHPP and associated facilities, administration and bathhouse, rail loop and loading facilities (Hansen Bailey, 2013, p. 1). In November 2010, Coal and Allied, in consultation with their joint venture partners, reached agreement on a A$141 million expansion of Bengalla. Under the development consent of the Bengalla Continuation Project a new ROM hopper and associated product coal stockpile will be built, and modifications will be made to the CHPP to facilitate two-stage washing (NSW Department of Planning and Environment, 2015b). The addition of two permanent tailings drying areas and a laydown area with associated facilities, along with the purchase of additional mining equipment, was also included in the upgrade. Current resources and reserves for Bengalla of 417 Mt and 171 Mt, respectively, are reported in the OZMIN database.

Licences related to Bengalla operations include (Hansen Bailey, 2013, p. 25):

Excess water accumulated on site is discharged into the Hunter River in accordance with the Hunter River Salinity Trading Scheme. Under pre-mining conditions groundwater flowed from the Permian rock units to the overlying alluvium. The extension of Bengalla’s operations is estimated to result in a maximum flow reduction to the alluvium of approximately 0.63 ML/day at the beginning of the extension operations. Groundwater modelling shows that as mining moves away from the alluvium, the reduction in flow decreases to approximately 0.25 ML/day in later years (Hansen Bailey, 2013, p. 182).

The aim of Bengalla’s rehabilitation plan is to re-establish agricultural land with at least 10% open woodland corridors across all disturbed areas, with the exception of the eastern face of the overburden emplacement area. The eastern face of the overburden emplacement area will be rehabilitated to contain a higher density woodland community to assist with further mitigating adverse visual impacts (Hansen Bailey, 2013, p. XV).

An ecological impact assessment was undertaken by Cumberland Ecology to determine the impacts of Bengalla’s extension on biodiversity values, including threatened species, populations and ecological communities. The mine disturbance area is projected to affect approximately 881 ha of native vegetation, including forest and woodland communities. An additional 69 ha of non-native vegetation will be removed, including tree and shrub plantations. The project will remove approximately 554 ha of threatened ecological communities including 535 ha of critically endangered Box Gum Woodland. This area to be impacted represents 9% of the species community in the Hunter Valley, and 0.2% of this community in NSW (Hansen Bailey, 2013, p. XIV–XV).