Coal mining in Australia is a major industry that contributes significantly to the economy, particularly in regions like Queensland and New South Wales. The processing of coal involves several stages, from extraction to preparation for export or domestic use. Here’s an overview of the key steps:
1. Coal Extraction
– Open-cut (Surface) Mining: Used when coal seams are close to the surface (e.g., Hunter Valley, Bowen Basin). Large machinery removes overburden (soil and rock) to access coal.
– Underground Mining: Used for deeper coal seams (e.g., Illawarra region). Methods include longwall mining and bord-and-pillar mining.
2. Coal Processing (Beneficiation)
After extraction, raw coal contains impurities (rock, dirt, sulfur, minerals) and must be processed:
– Crushing & Screening: Coal is crushed into smaller pieces and screened to separate by size.
– Washing (Coal Preparation Plants – CPPs): Removes impurities using water and chemicals. Techniques include:
– Dense Medium Separation: Uses a liquid mixture (e.g., magnetite and water) to separate coal from waste.
– Froth Flotation: Fine coal particles are separated using chemicals that make coal hydrophobic.
– Jigging & Spirals: Gravity-based methods to separate coal from heavier rock.
– Dewatering: Removes excess water from washed coal using centrifuges or filters.
3. Quality Control & Sorting
– Coal is tested for moisture, ash content, sulfur levels, and energy value (measured in megajoules per kilogram, MJ/kg).
– Different grades are separated:
– Thermal Coal (for power generation)
– Coking/Coking Coal (for steelmaking)
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4. Transport & Export
– Processed coal is transported via:
– Trains (e.g., to ports like Gladstone, Newcastle)
– Conveyors & Trucks (for shorter distances)
– At ports, coal is stockpiled before being loaded onto ships for export (Australia is the world’s largest exporter of metallurgical coal and a top thermal coal exporter).
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5. Environmental & Safety Considerations
– Water Management: Coal washing uses large amounts of water; treatment is required before discharge.
– Dust & Emissions Control: Spray systems and enclosures reduce dust at mines and ports.
– Rehabilitation: Mining companies must