Geologically the Mandalong Area is located in the south-west of the Newcastle Coalfield, a geological subdivision of the north-eastern Sydney Basin. The coal deposits of this area are contained within sedimentary rocks of the Late Permian Age Newcastle Coal Measures, which are characterised by complex patterns of splitting and coalescence of the various coal seams.

The significant coal seams within the Area are the Wallarah, West Wallarah, Great Northern and Fassifern Seams. The term “West Wallarah Coal Seam” was introduced by Centennial Mandalong and has been used at Mandalong Mine to define the coal seam formed by the westerly convergence of the Wallarah and Great Northern Seams.

Other significant units, which lie within the stratigraphic section, are the Awaba Tuff Formation, which lies between the West Wallarah and Fassifern Seams, and the Munmorah Conglomerate, which sits within the Triassic Age Narrabeen Group sediments between 80 m to 110 m above the West Wallarah Seam and Wallarah-Great Northern Seams. This conglomerate beam has a significant impact on the subsidence profile for the Mandalong Mine due to its spanning potential.

Centennial Mandalong has approval to use longwall mining and bord-and-pillar mining methods to extract up to 6.5 Mtpa of ROM coal from the West Wallarah and Wallarah-Great Northern Seams.

The proposed mine plan within the Southern Extension Area encompasses a total of 40 longwall panels ranging in length between approximately 1,000 and 3,500 metres, depending on seam conditions and site constraints, and ranging in width between 160 and 200 metres.

During the MOP (Mine Operations Plan) Term Mandalong will develop and extract Longwall 21 to 24A. Following the completion of mining in ML 1433, secondary extraction will commence in the Southern Extension Area (i.e. within ML 1722 and ML 1744).

All ROM coal from Mandalong Mine is delivered via underground and surface conveyor systems to either the CES or the Delta Entry Site for coal crushing and sizing.

Coal from the underground operation is sized underground by a 4,000 tonnes per hour (tph) sizer and fed to an underground surge bin. Coal from the bin is delivered to either the Cooranbong or Delta coal clearance systems. The Cooranbong clearance system transfers coal underground by 1,200 mm conveyor belts to a 2,000 t capacity ROM bin on the surface. The Coal Handling Plant (CHP) processes up to 700 tph.

Coal from the ROM bin enters the CHP and is then discharged via a syntron feeder onto a conveyor belt where a magnet removes metal prior to being discharged into a rotary breaker at the CHP to reduce the size of coal to less than 200 mm. Large pieces of stone are separated in the breaker and discharged into a separate stone bin with a 50 t capacity. The coal is then conveyed into an intermediate 400 t c ........