The Sydney Basin of eastern New South Wales is a structural unit that contains both Permian and Triassic sediments in addition to volcanic and alluvial deposits referrable to the Tertiary. The Permian succession consists of two thick groups of marine strata, each succeeded by coal measure sequcnce.

The Dalwood Group at the base is composed essentially of marine shales and sandstones with basaltic lavas and sporadic conglomerates. The overlying Greta Coal Measures consist of lenticular beds of conglomerate, shale, lithic sandstone, coal, and, in the Upper Hunter Valley, unusual thicknesses of kaolinite claystone.

Siltstones, sandstones, and conglomerates predominate in the Maitland Group, which has a probable maximum thickness of 4,000 feet.

The operation consists of a number of facilities and equipment necessary for the extraction, washing and distribution of coal which includes:

• infrastructure area, which is composed of three coal stockpiles, a c oal handling and preparation plant (CHPP), workshop and nearby office complex;
• rail load out facilities;
• mobile plant and equipment;
• dragline;
• run of mine hopper; and
• the mobile fleet of equipment at Bengalla enables the progressive pre-stripping and r emoval of overburden by loader, excavator and t rucks in advance of the dragline .

The Bengalla mobile equipment fleet consists of well maintained modern mining equipment, which incorporates some of the latest mining technology.

At the end of 2014, Bengalla’s mining fleet consisted of one dragline, one loader and five excavators, 22 haul trucks, and five water carts (including one hired CAT 777 water cart).

Following the removal of overburden and interburden layers,the exposed coal seams are mined and transported to the ROM hopper where it is crushed to less than 250mm. The crushed coal is then transported along the new 300 metre conveyor to the crushing station. Where practical all conveyors are enclosed to reduce both noise and dust emissions. The coal is crushed to a top size of 50mm and can be by passed to product, direct fed into the CHPP or transported and stockpiled on the raw coal stockpile. All stockpiles utilise dust suppression and process strategies to minimise dust emissions.

The CHPP utilises dense medium cyclones (-50mm +1.4mm) and single stage spirals (-1.4mm +0.125mm) to process coal to meet customers’ product specifications. This allows maximum resource recovery of the ROM coal.

Unlike conventional CHPP processing plants, Bengalla has no tailings dam and ultrafine material less than 0.125mm is thickened, dewatered on belt press filters and then combined with other reject streams for final disposal back into the spoil. The handling of reject material is undertaken in accordance with mining operations plan commitments and Coal & Allied’s coarse rejects and tailings disposal procedure. The CHPP processes and facilities were not modified during the reporting period.