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.

Mandalong Mine is a modern underground longwall operation located on the western side of Lake Macquarie near Morisset and west of the M1 Motorway. The Mine is situated approximately 130 km north of Sydney and 50 km from the Port of Newcastle, supplying up to 6.5 million tonnes of coal to the domestic power and export markets.

Mandalong Mine comprises the underground workings and surface infrastructure of:
• The Mandalong Mine underground workings including longwall panels, development units and surface infrastructure located near Morisset;
• The Cooranbong Entry Site, consisting of the Cooranbong Colliery underground workings and surface infrastructure located near Dora Creek;
• The Mandalong South Surface Site located off Mandalong Road; and
• The Delta Entry Site, which encompasses an entry and coal delivery system, located near Wyee at the Vales Point Rail Unloader Facility.

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.

The primary components of the Project are:

• Continue the currently approved operations at the Mandalong Mine, with the exception of the surface infrastructure and operations at the Cooranbong Entry Site (i.e. the continued use of the coal delivery system, the ventilation shaft and the extent of workings at Cooranbong Entry Site for water management).

• Extend the Mandalong Mine’s underground mining operations into the Southern Extension Area using a combination of continuous miner and longwall mining methods;

• Extract up to 6.5 Mtpa of ROM coal from the West Wallarah and Wallarah-Great Northern Seams within the current mining lease areas;

• Deliver ROM coal from the underground workings to the Cooranbong Entry Site at a rate of up to 6 Mtpa and to the Delta Entry Site at a rate of up to 6 Mtpa;

• Continue to utilise, and upgrade where required, the existing surface infrastructure of the Mandalong Mine Access Site and Delta Entry Site;

• Install and operate surface infrastructure at the proposed Mandalong South Surface Site to service the extended underground mining operation;

• Increase manning to 420 full-time employees and up to 50 contractors during longwall relocations;

• Undertake on-going exploration drilling activities within the bounds of Centennial Mandalong’s mining leases and exploration licences;

• Increase the life of mine to 25 years from the granting of a mining lease(s); and

• Continue to operate 24 hours per day, seven days per week.

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 ........