Abstract The Collie Basin is a fault-bounded, post-depositional pull-apart structure containing approximately 1200 m of generally southwesterly dipping Permian siliciclastics preserved as a consequence of right-lateral shear in a transtensional setting. Gravity and drilling data indicate the basin is 226 km' in area and that it comprises two weakly folded grabens striking northwest. The coal-bearing section reaches a maximum thickness of 900 m, of which up to 74 m consist of coal in 60 principal seams between 0.5 and l 3 m thick. Permian stratigraphy is revised: Collie Coal Measures and Stockton Formations are raised to group status; Cardiff, Collieburn and Chicken Creek Members are discarded; new formations include Muja Coal Measures, Allanson Sandstone, Westralia Sandstone, Moorhead and Shotts Formations; the Premier and Ewington Members are raised to the rank of coal measures. Lithostratigraphy is integrated with biostratigraphic palynomorph zones and includes deposits from Permo-Carboniferous to Early Kazanian in the Late Permian. Significant tectonics in the Permian of Western Australia are inferred from vitrinite reflectance determinations, which indicate that maximum coal-burial depth approached 8 km. A suspected lacuna exists between the Muja Coal Measures and the underlying Premier Coal Measures, coincident with the appearance of Didecitriletes ericianus and a jump in vitrinite reflectance from 0.4 to 0.6%. The Permian strata are unconformably overlain by a veneer of Cretaceous (Neocomian) deposits. The Ewington Coal Measures and underlying sediments constitute a broadly upwardcoarsening glaciofluvial and glaciolacustrine deltaic succession that formed in response to climatic amelioration and glacial retreat of the Gondwana ice sheet; this constitutes Permian genetic Sequence I (Pl). Fluvial to upper delta-plain alluvial coal deposition constitutes the balance of the succession. Collie coal resources, determined in accordance with the Australian code f(1r reporting identified coal resources and reserves, total 2400 Mt. Approximately 37% of the coal lies in the current opencut mining window. Maximum vitrinite reflectance averages 0.43 in the Muja Coal Measures and 0.60 in the deeper Premier and Ewington Coal Measures. On a modified Coded Commercial Classification System the coal type is humic with a range between code 2 (vitric) and code 7 (inertic) and reactives constituting up to 80%. The coal rank is (meta) subbituminous in the Muja Coal Measures and crosses the vitrinite reflectance boundary (0.5%) to (hypo) bituminous in the Ewington and Premier Coal Measures. Tabulated qualities of Collie coal include proximate and specific energy, sulfur, ash fusion temperature, abrasiveness, Hardgrove grindability, ultimate, ash, trace element, petrographic and maceral analyses. Specific energy is l 8.0-22.0 MJ/kg (as received) and 29.0 to 31.9 MJ/ kg (dry ash free), moisture content is approximately 25% (ar), ash content is 3-10% (ar), volatile matter is 22-37 % (ar). fixed carbon is 37-50 % (ar) and 54-6 l % (daO. and sulfur is 0.29-0.49%.

Premier Coal runs a modern open cut mine employing large electric & hydraulic shovels and 240- tonne haul trucks.

Geology of the Premier Basin is considerably different allowing the use of larger mining equipment such as electric shovels, a first for the basin, and 240-tonne capacity trucks. Pits 3 and 1D exploit the Premier seams and Pit 5 exploits the Ewington seams. The Premier seams are relatively flat allowing the use of the electric shovels, while the Ewington seams are steeply dipping, requiring a benched approach using hydraulic excavators.

The Mine is supported by sophisticated geological models and mine planning systems that combine to produce detailed, optimised schedules to ensure customer expectations of quality and quantity are consistently met in a timely manner.

Coal is mined using large excavators and 240-tonne trucks. On delivery to the coal plant, the coal is passed through a simple crushing and screening plant prior to stockpiling using a stacker/reclaimer system. Coal is delivered to local power station customers by conveyor and to other customers by rail or truck.

Key to the operations is a modern maintenance workshop and a mobile maintenance function for in- pit shovel and breakdown maintenance.

The whole operation is state-of-the-art with many functions, from fleet dispatch to dozer grade control, reliant upon extensive computer systems.

The high quality of Premier coal allows for a simple preparation process of crushing and screening. The system has a capacity of 1,200 tonnes per hour. Coal is typically crushed to a nominal top size of 50mm and screened “nut” products can be produced to suit customer needs. Premier’s modern stacker-reclaimer system produces a highly uniform quality. Online analysis, supported by automatic sampling and laboratory analysis, ensures stock piles are built accurately to customer specification.

Coal is supplied to Synergy's generating plant by conveyor. The Company has good rail and road access to other customers in Western Australia.

Premier Mine produces a clean coal with low ash and sulphur content such that it does not need to be washed and requires only crushing, sizing and blending prior to use.

The coal handling equipment installed at the Premier Mine is very effective. The system has been designed to supply coal in a very consistent way so that the ........