What Comes Out Of The Mine And Where Does It Go?
The Metropolitan Colliery, Helensburgh’s underground mine, produces coking coal for both domestic and export markets with Peabody Energy. The company owns eleven mining operations in Queensland and New South Wales, and has active coal trading throughout all of Australia’s major coal regions through Peabody COALTRADE.
Some of Peabody’s major export customers include electricity generators throughout Asia, as well as steel producers in Japan, Europe, Taiwan, India and South America. Peabody Energy also owns multiple mining operations in the United States, China, Mongolia and Indonesia. The Metropolitan Colliery, which exports coal from coal carrying ships docked and stocked at Port Kembla, sold two million tonnes of hard coking coal in 2016.
Although Peabody deals in a range of different products such hard and semi-hard coking coal, thermal coal, and PCI (pulverised coal injection) coal, the mine at Helensburgh is primarily used to produce coking coal.
‘Coking’ coal refers to a relatively soft, low-ash, low-sulphur bituminous (or ‘black’) coal. This type of coal is used to make ‘coke’ (not to be confused with the soft drink!), a substance used in the manufacture of iron and steel. Coke is a dry, solid residue derived when coking coal is baked to 1,0000C in an oven without oxygen. This results in the volatile constituents being driven off, and the fixed carbon and residual ash fused together as coke.
Metallurgical coke is used in the smelting of iron ore in blast furnaces. The resulting ‘pig iron’, which is very brittle, must be further treated to make steel. The strength of the steel relies on the coke being low-volatile, so the blast-furnace smelting process is not tainted by sulphur and phosphorus.
The bituminous coal found in the Helensburgh mine is an organic sedimentary rock. It is formed by a diagenetic (chemical and physical change in deposited sediment) and sub-metamorphic compression of peat bog material. This coking coal is extracted via longwall mining techniques and transferred to the surface facilities area by conveyor. The majority of the coal is transported by train to the Port Kembla coal terminal for domestic and international shipping. A small amount is also transported by truck to the nearby Coalcliff and Corrimal coke works.
The extraction of this coal can have negative environmental effects, which has environmentalists concerned. These effects include:
- Contamination of land and waterways
- Interference with groundwater and water tables
- Release of carbon dioxide, a greenhouse gas which contributes to climate change
Peabody Energy has sought to address these concerns over recent years, by rolling out award-winning environmental initiatives for their operations. Their stated mission is striving to leave the land in the same (or even better) condition than they found it.
The Metropolitan Colliery at Helensburgh actually pioneered the use of polyurethane resin injections to fill localised shallow surface cracking. This process restores surface flows in the Sydney Drinking Water Catchment. Work continues with scientific and environmental experts to develop this technology. Helensburgh mine is also trialling the innovative underground emplacement of reject material via established mine backfill technology – essentially putting back what they don’t need. These trials will eventually lead to the elimination of trucking waste offsite, which will also eliminate the environmental hazards of excess waste.
Images/Photos, and Article © Ian Piggott 2017 – all rights reserved,
