Blasted ore from the open-pit is delivered to the in-pit gyratory crushers by a fleet of 350 tonne haul trucks. The crushed ore is first transported to the coarse ore stockpile by conveyor belts, then fed to each of the six parallel milling lines using apron feeders and conveyor belts.
Each of the milling lines consists of a primary autogenous (AG) mill and a secondary ball mill. Following the AG mill, the first stage of magnetite separation produces low grade concentrate and rejects non-magnetic tails at coarse size.
Another two stages of magnetic separation occurs after the ball mill, to produce final high grade concentrate. After thickening the concentrate is pumped in slurry form via the 30km pipeline to the dewatering plant at the port area. The moisture of filtered concentrate cake is around 9%.
Meanwhile tailings are thickened and then pumped to the tailings storage facility (TSF). The extracted water from tailings and concentrate thickeners is pumped back to the concentrator for re-use.
Facts & Figures
- Four in-pit crushers from Germany – the largest installation in Australia, with capacity to crush 4,250 tonnes of ore per hour per unit.
- The conveyor carrying crushed ore from the mine to the concentrator area is 2.4m wide and 1.7km long.
- The largest AG mills in the world, they’re 12.2m in diameter and 11m long with 28MW gearless motors.
- The ball mills, the second stage grinding equipment, are 7.9m in diameter and 13.6m long, each with two 7800 kW motors.
- 52 magnetic separators are used in each of the processing lines.
- Two concentrate thickeners, each 45m in diameter and four tails thickeners each 90m in diameter.
- Four dewatering buildings, each containing seven press filters.
- Each press filter has a design capacity of 154 tonnes of concentrate per hour.