PERTH (miningweekly.com) - ASX-listed PanAust on Friday reported that the plant scale test work at its Phu Kham increased recovery project, in Laos, had proved positive.
The four plant-scale tests on a variety of ore blends have returned an increase in copper recovery from 7.5%, with a range from 5% to 11%. For gold, the average recovery increase was more pronounced at 15.8%, with a range from 11% to 20%.
The increased-recovery project was designed to increase both the copper and gold recovery rates at the Phu Kham operation, on an average of six percentage points. This would lift the current estimated mine life copper recovery rates from 77% to at least 83% and the gold recovery rates from 47% to at least 53%.
The increased recovery rates would also be higher for the more complex transitional ores than for the primary ores, which inherently run higher average recovery rates.
PanAust noted that where mill throughput rates exceeded the post upgraded nameplate of 16-million tons a year, it was likely that some metallurgical recovery potential might have to be sacrificed in favour of increased concentrate output, and therefore, metal production.
The increased recovery project stemmed from a two-year evaluation of various technologies that could potentially improve the metallurgical recoveries at Phu Kham.
The plant-scale test work confirmed that by incorporating a strategy of less selective flotation, in combination with additional regrind and cleaner capacity, recovery rates for both copper and gold could be materially increased, the miner said.
The estimated capital cost for the project has been set at $20-million, compared with an initial $45-million estimate.
PanAust has predicted that copper production at Phu Kham would increase over the next three years, while current 2012 production guidance remained at between 63 000 t and 65 000 t of copper and between 50 000 oz and 55 000 oz of gold.
Copper production would increase by between 65 000 t and 70 000 t in 2013, and to between 70 000 t and 75 000 t in 2014.
Meanwhile, in parallel with the implementation of the capital projects, PanAust would also complete its first mineral resource estimate for the adjacent Nam San copper/gold deposit, which could provide a future source of feed for the Phu Kham processing plant.
Studies and development work to access the Nam San deposit would be completed over the next three years.
