Galaxy Resources wholly owns the Mt Cattlin spodumene project, located two kilometres north of the town of Ravensthorpe in Western Australia. In July 2012, Galaxy advised that it would halt its operations at Mt Cattlin to focus on production at the Jiangsu plant. Previously Galaxy was mining pragmatic ore at Mt Cattlin which was processed on site to produce a spodumene concentrate and a tantalum by produce. At full capacity, ore could be processed at a rate of one million tonnes per annum (tpa) with lithium oxide concentrate production of 137,000 tpa and 56,000 pounds (lbs) per annum of contained tantalum (TA2O5).
Galaxy Resources holds a series of tenements surrounding and including the mining lease M74/12, which contains the majority of the spodumene (LiAlSi206) resource identified to date and which hosts the Mt Cattlin mine. In a resource estimate issued in March 2011, Mt Cattlin's total contained lithium oxide (Li2O) resource was 197,000 tonnes, the measured and indicated resource was 13.8 million tonnes and total resource ore tonnes were 18.18 million. The current life potential of the Mt Cattlin mine is 18 years, including inferred resources.
The Mt Cattlin mine operations include open-pit mining of a flat lying pegmatite ore body. The flat lying nature of the ore body allows mining to proceed at a constant strip ratio once the ore is uncovered. Mining is carried out using excavator and truck operations, delivering to a conventional crushing and HMS gravity recovery circuit. Contract mining is used for grade control drilling and earthmoving operations (drilling, blasting, load, haul and ancillary work) for the open-cut mining operation. The pit design encompasses existing measured and indicated resources and has been defined as the Dowling pit.
The processing plant at Mt Cattlin is located to the west of the Dowling pit, approximately 2 kilometres north-west of the Ravensthorpe townsite. The plant consists of a 4-stage crushing circuit producing a -6mm product from ROM ore at a treatment rate of 1 million tonnes per annum. The crushing plant provides feed to a fine ore bin and this fine ore bin feeds the concentrator on a continuous 24 hour per day basis.
The concentrator consists of reflux classifier, dual size steam, two stages of Heavy (or Dense) Media Separation (HMS) cyclones, with mechanical attritioning of the intermediate sink product. The final spodumene concentrate is stacked on a pad adjacent to the plant area, drained and prepared for trucking to port.
Coarse waste HMS plant float material is collected in a surge bin and then trucked to either the waste dump or to mined out areas of the pit(s) as back-fill. There is a possibility that this material could be sold as a by-product. The HMS pre-screen undersize (-0.5mm) is treated by gravity suspension (spiral classifiers) to recover tantalite and residual spodumene). Tantalite circuit tailings and other plant spillage streams are directed to a thickener for process water recovery. Thickener underflow is pumped to a tailings dam approximately 500 metres from the plant.
The key process steps are:
- Open pit mining
- Crushing and screening to -6mm
- Reflux Classifier to remove mica flakes
- Two stage heavy media separation (HMS) in two separate size streams
- Gravity concentration (spirals and wet tables) of tantalite minerals
- Production of 137,000 tonnes of spodumene concentrate
- Shipment of bulk concentrate to Zhangjiangang in China
Power on site at Mt Cattlin is provided by a dedicated diesel generator supported by state-of-the-art solar tracking technology. Galaxy has 14 giant solar trackers and 2 wind turbines in operation at Mt Cattlin, which together generate 226 MWh per year of renewable energy. Mt Cattlin was the first mine site in Australia to have real-time solar tracking panels as part of its power generating requirements. The solar tracking feature means the solar panels are able to follow the sun in all directions to maximise the power generated and provide 15% more power than a single axis system.
The wind and solar hybrid system supplements power from Galaxy's 5MW diesel generator, which accounts for, on average about a sixth of the mine site's daily power. This system also promotes savings in CO2 emissions amounting to 200 tonnes every year.