Ore sorting was successfully used at Mt Carbine between 1973 and 1986, however there have been major advances in the type and efficiency of ore sorters since they were last used at Mt Carbine. During late 2010, Carbine Tungsten Limited carried out trials using a state-of-the-art transmission X-Ray ore sorter on bulk samples taken from the ~12 million tonne low grade stockpile left untreated by the previous mining operation. The results were highly encouraging, with the sorting achieving a conservative upgrade of more than 8 times the bulk sample grade.
The results are regarded as a “game changer” for the redevelopment of Mt Carbine. Following on from the tailings re-treatment, Carbine Tungsten Limited is now planning to re-treat the low grade stockpile over a period of 4-6 years at a production rate of ~100 tonnes WO3 per month, before it commences hard rock mining.
The dramatic reduction of the amount of rock to be milled for final product results in major reductions in capital expenditure (the mill is much smaller) and operating costs per unit of product. The net result is that the Mt Carbine project now has a long project life and a much reduced project risk.