Washpool Hard Coking Coal Project, Australia
The Washpool Hard Coking coal project is an open pit mine located in Queensland, Australia approximately 260km west of Rockhampton, 60km north-east of Emerald and 24km north-west of Blackwater. Owned by Aquila Resources, the project is currently in the planning stage.
The feasibility study of the project, which was completed in July 2010, confirmed its technical and economic viability. Construction of the $320m project will begin in 2012 and the mine will be developed into a 4mtpa open pit operation with the first coal expected to be mined in 2013.
The deposit consists of six seams that together contain 138mt of indicated and inferred resources. Indicated resources have been estimated at 33.8mt while inferred resources stand at 104.3mt. The coal is primarily hosted in the Scorpio and Centaur seams of the deposit.
The Washpool project lies within the Burngrove formation that conformably underlies the Rangal Coal measures.
Coal is hosted within a 6km-long and 3km-wide perched basin that remains closed from all sides.
The depth limit of the basin is determined by its structure and averages 42m. The maximum depth of cover to the top of the coal is 60m at the middle of the basin. Shallow limits are defined by the base of weathering range between 22m and 35m.
Overburden material includes unconsolidated river alluvials and units of fine sandstone and mudstone.
Along the margins of the basin, the coal extends to sub crop. Average thickness of the coal seams is 6m including six plies, stone bands and 1.5m to 2m of interburden and partings.
Coal seams are banded, contain a high content of raw ash and have good coking coal characteristics. Towards the north, south and west the coal is limited by seam sub-crops while it is defined by seam thinning towards the east.
Mining techniques at the proposed mine will include open cut truck and shovel mining and a set of one or two draglines. Emphasis will be on pit waste dumping. Due to the geometry of the deposit, mining strips of east-west orientation are considered to be suitable along the longer axis of the basin structure.
The initial box cut will be located in the shallowest depth to coal, the north-western end of the basin from where the overburden will be removed out of the pit.
Strip mining will progress east and southward with initial overburden removed from the pit.
Due to thickness of the seam, which is composed of several plies separated by interburdens, a selective mining method or a complete mining method in combination with a waste strategy will be required.
Mining will be carried out at 4mtpa ROM coal that will produce between 1.6mt and 2mt of product with 15% ash. On average, removal of between 30m and 40m bank cubic metres of overburden will be required annually to meet the planned capacity.
A coal handling and preparation plant (CHPP) and facilities for rail load out will be constructed towards the south of the deposit. The CHPP will operate at a capacity of 600tph of feed and processing capacity of 4mtpa. It will operate throughout the week.
The plant infrastructure will include an ROM pad, ROM coal delivery system, coal washery module, delivery system for coal waste and clean coal, product stockpile, fuel farm and workshops.
The project site will be connected to regional systems. Currently the mine site can be accessed via publicly gazetted roads. The mail haul roads within the project area will be constructed along north-south to connect the mining area to the ROM pad and along east-west to connect to the several waste dumps on site. Mined coal will be delivered via the Blackwater railway system to the Gladstone port for shipping.