Oaky Creek lies in the central Bowen Basin, next to Rio Tinto’s Kestrel mine. The Bowen Basin contains the largest coal reserve in Australia. This major coalproducing region contains one of the world’s largest deposits of bituminous coal. The Basin contains much of the known Permian coal resources in Queensland including virtually the entire known mineable prime coking coal. The Bowen Basin covers an area of over 60,000 square kilometres in Central Queensland running from Collinsville to Theodore.

The foreland, Early Permian to Middle Triassic Bowen Basin of eastern Queensland occupies about 160,000 km2, the southern half of which is covered by the Surat Basin. It has a maximum sediment thickness of about 10,000 metres concentrated in two N trending depocentres, the Taroom Trough to the east and the Denison Trough to the west. Deposition in the basin commenced during an Early Permian extensional phase, with fluvial and lacustrine sediments and volcanics being deposited in a series of half-graben in the east while in the west a thick succession of coals and nonmarine clastics.

Following rifting there was a thermal subsidence phase extending from the mid Early to Late Permian, during which a basin-wide transgression allowed deposition of deltaic and shallow marine, predominantly clastic sediments as well as extensive coal measures. Foreland loading of the basin spread from east to west during the Late Permian, resulting in accelerated subsidence, which allowed the deposition of a very thick succession of Late Permian marine and fluvial clastics, again with coal and Early to Middle Triassic fluvial and lacustrine clastics.

Sedimentation in the basin was terminated by a Middle to Late Triassic contractional event. Over 100 hydrocarbon accumulations have been discovered in the Bowen Basin, of which about one third are producing fields. Accumulations occur throughout the succession, but the most important reservoirs are in the Early Permian and Middle Triassic. Source rocks have been identified throughout the Permian and in the Middle Triassic and are mostly nonmarine. Proven plays comprise mostly anticlinal closures sometimes enhanced by a stratigraphic component, as well as fault rollovers. The Large volumes of methane gas are held at shallow depths within Permian coals in the north and has potential for coal seam methane developments.

The OCC (Oaky Creek Coal complex) complex mines from two seams the German Creek, which can be up to 4.5 metres thick, averaging 2.6 metres. The Aquila seam is thinner, averaging 1.4 metres, but is of complementary quality to the German Creek seam.

The Oaky Creek Underground Mine develops underground workings followed by longwall extraction methods.

The operation was commenced in October 1995 with a single continuous miner development operation manned 24 hours per day five days per week. A second continuous miner unit was brought on line in January 1997. In December 1997 a third unit was added, to be manned on a part time basis.

The mine is characterised by a number of innovative approaches to underground mine project development, all of which have proved to be overwhelmingly successful and will ensure its place amongst the world's best.

Longwall opeations.
A longwall was installed in January 1999. The faces are 260m centre to centre with the extraction height of the first eight panels over 4.5m. The longwall is the highest capacity commercially available utilising state of the art automation to minimise the need for operators on the face.

The conveyor system to handle the longwall coal includes 1600mm gatebelts rated at 4,500tph continuously, running at 4.4 m/s. These discharge onto a 2000mm trunk belt rated at 6,500 tph continuously, running at 4.1m/s. The first trunk belt is a 2.7km long single flight conveyor servicing the first six panels with the single drivehead located in the fresh air at the highwall portal. The coal is taken by a similar belt up an open cut ramp and discharged onto a 150,OOOt single cone ROM stockpile. The coal is then reclaimed and transported to the Coal Preparation Plant by overland conveyor.

Run of mine coal is transported from the underground mines directly to the surface raw coal stockpiles by high capacity conveyor belt systems. From these stockpiles the coal is fed through rotary coal breakers, which size the coal and make an initial segregation of waste rock material. It is then conveyed to stackers which place the raw coal on a series of stockpiles one for each of the qualities being mined.

Vibrating feeders reclaim coal from these stockpiles. It is then blended to ensure consistency of quality and fed to the preparation plant for washing. The preparation plant consists of four parallel modules. Each module has a heavy medium system for treating coarse coal of 50*1mm, a primary spirals unit treating the 1.0 *0.2mm size fraction and froth flotation for processing fines of less than 0.2mm. A secondary spirals unit processes misplaced material from the primary spirals circuit.

Horizontal belt filters where fitted to replace the original drum filters on the fines circuit. This has improved both the throughput capacity and the recovery of high quality fine coal. Fine reject material from the preparation plant goes to a thickener for concentration and is later transferred to a tailings storage facility. Clarified water from the thickener and tailings storage facility is pumped back to the plant for re use in the washing process.

A radial stacker places the washed product onto separate areas of the product stockpile depending on grade. As it leaves the preparation plant, the product coal is sampled and analysed continuously to ensure that quality meets contract specifications. All operations of the preparation plant are governed from a central control room, and monitored by modern sensing and control equipment.

The OCC complex produces premium quality, medium volatile coking coal. The coals contain moderately low ash, low sulphur and low alkalis and exert negligible pressure on coke oven walls. The Oaky Creek coals exhibit plastic properties such as high fluidity and high dilatation, which are exceptional for this rank of Australian coal.