Vista Gold Corp. (Vista) yesterday announced excellent leach test results from the ongoing metallurgical test work at its Mt Todd gold project located in Northern Territory (Australia). These results are the first from a number of metallurgical tests being conducted on material from the Batman deposit. Leach tests on material with an 80% passing (P80) grind size of approximately 50 μ achieved average gold recoveries of 92.7%. Gold recoveries at coarser grind sizes were consistent with previous test results on similarly-sized material. Additional leach test work on samples with a finer design P80 grind size of 40 μ is nearing completion, with final results expected in the coming weeks.
Initial leach test results are from high-grade and deposit-average grade composites from the Batman deposit. Samples BR153 and BR154 had individual head grades of 1.96 and 1.90 grams gold per tonne (g Au/t), respectively, while Samples BR161 and BR162 had individual head grades of 0.72 and 0.73 g Au/t, respectively. Assays were completed in triplicate. The reported gold recovery is based on the average of the three assays.
Frederick H. Earnest, President and CEO, commented, "We are very encouraged by these results, which further support our confidence that finer grind sizes will yield higher gold recoveries. Our design contemplates a P80 particle size of 40 μ. The current testing is being completed on samples with estimated head grades of 0.8 - 1.7 g Au/t at target grind sizes of 45, 38 and 30 μ. We expect to receive the remaining leach test results in batches over the next several weeks and anticipate recoveries to be in the low ninety-percent range, consistent with the results above and our work as previously announced in August 2018. This is a significant improvement from the average gold recoveries of 86.4% reported in the January 2018 prefeasibility study and represents the potential to recover approximately 300 000 more ounces of gold over the life of the project."
The comprehensive results will be incorporated into an updated prefeasibility study currently scheduled for completion in the third quarter of this year.
Read the article online at: https://www.globalminingreview.com/exploration-development/30052019/vista-gold-reports-mt-todd-leach-test-recoveries/