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.

Exploration at Oaky Creek began in 1977 and in 1981 MIM acquired a major stake in the operation. In 1983 the mine was officially opened, initially as an open cut dragline operation. But underground operations commenced in 1989 to increase coal production as the open cut mine became deeper and stripping ratios increased. Longwall operations at Oaky No 1 began in 1990 and Oaky North development started in 1995. The Oaky Creek No 1 mine was developed from the highwall of a worked out open cut pit close to the preparation plant. The longwall extracts coal from a series of pre- developed blocks.

Mining operations at Oaky Creek No 1 ceased during 2017.

Oaky Creek North was developed as a major longwall mine and is generally a larger scale operation than the Oaky No 1 mine, thicker seams, wider longwall blocks and bigger more powerful equipment. In both mines continuous miners develop the blocks for longwall extraction, maintaining minimum developed longwall inventories of at least two blocks at all times. The underground mines at the OCC complex have optimum working conditions with a stable roof, floor and coalface and an above average seam thickness.

When production commenced in 1998, coal recovery became less economically profitable and therefore the open cut mine was closed in 1999. Changes in the exchange rates and coal prices saw the open cut operation become economical again, reopening in 2001 with two draglines in the high quality Aquila seam. Finally in December 2006 the open cut operation was closed again.

The OCC complex produces premium quality, medium volatile coking coal.

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 filte ........