Coal is conveyed from the seam via 350 metres of stone driveage to the top of the 2000 tonne capacity surge bin some 35m above.

The coal is then metered via a conical hopper system into 2x2000t/hour vibro feeders that control the coal flow to external power stations.

The Eraring power station utilises the old Cooranbong workings to deliver the coal into the screening plant on the Cooranbong surface some 12km away, before being sent to the power station via the overland conveyors.

Coal for the Delta power station goes via the 4.5km underground conveyor system to be screened and delivered onto the overland conveyor system at the train unloader station on Rutleys Road.

The project was divided into several major mining contracts. Surge bin access roads, surge bin shaft construction, manufacture and installation of the surge bin metering hoppers and feeders and the extension of the Delta production unit workings to intercept the surface drift.

CMS Underground Construction was involved with all the contracts excluding the surface drift.

The surge bin access roadway was driven in stone at a gradient of 1 in 6.

The company’s Mitsui S200 handled the mining work in the single entry driveage to the top of the surge bin and then constructed the shaft top chamber.

In addition to this preliminary driveage, CMS also constructed the first overcasts for the No 1 longwall return and the main gate belt drive.

The underground access roads to the Mandalong surface drift along with 260m of the 1 in 8 drift, to assist in the timing of the project and finally 1000m of brushing to allow the longwall supports to be transported to the face line.

Surge bin shaft construction

An initial surge bin 2.7m shaft was raised through the bunker section from the surface and the shaft widened by drill and blast.

A 1m diameter raise bore was lined through to the surface to allow the top of the surge bin to be ventilated. Service pipes were installed and compressed air and shotcrete were supplied direct from the surface.

A purpose designed winding system was utilised for the construction allowing man and material access for the drilling, blasting, support and shotcreting to be carried out in safety.