PanTerra Gold (ASX: PGI) has clarified the various process parameters utilised to measure performance of the Albion/carbon-in-leach process plant treating high grade refractory tailings at its Las Lagunas project in the Dominican Republic.
The process plant aims to maximise both gold recovery and sulphide sulphur content in the slurry concentrate produced by the flotation circuit.
Following this, it then minimises sulphur content during the chemical reaction in the oxidation tanks, and prior to entry of the oxidised slurry to the standard CIL extraction process.
The tuning of the plant, which is currently in progress, is focused on the flotation circuit where performance is being affected periodically.
Performance is being affected by variability in density and particle size of the dredged feed to the plant, as well as by residual chemicals in the tailings from the previous operation of the Pueblo Viejo mine.
A new thickener is being installed to receive feed prior to its entry to the plant, which will allow blending from two points of delivery, and better control of density.
PanTerra's consultants are confident targeted sulphur levels and flotation gold recoveries will be delivered within the next one to two months.
Current flotation performance is:
Gold Recovery - Target: 83% Actual: 77.8%
Silver Recovery - Target 80% Actual: 72.8%
Sulphide Sulphur Level - Target: 16.9% Actual: 13.6%
Once the sulphur levels are increased in the flotation circuit to around 17%, the efficiency of the reaction in the Albion oxidation tanks will improve.
CIL recoveries will also improve as a consequence of lower refractory sulphides in the oxidised feed to the CIL tanks.
Brian Johnson, chairman and chief executive officer of PanTerra Gold, has recently returned from the Dominican Republic.
Johnson held positive discussions with Government authorities on the process plant remaining in place to treat refractory ore from the region when the tailings project is finished in December 2018.
The company has identified two potential feed sources that could significantly extend the life of the Las Lagunas Project.
Metallurgical testwork will begin in the near term on the suitability of the existing plant to treat the ores in question.
PanTerra had over $7.5 million in cash at the end of December 2012.
Proactive Investors Australia is the market leader in producing news, articles and research reports on ASX "Small and Mid-cap" stocks with distribution in Australia, UK, North America and Hong Kong / China.