Jun 17 2015
Discovery Ventures Inc. is pleased to announce it has received positive results from the current metallurgical test work program, conducted by MetSolve Labs on the intermediate-grade mineral samples from the Willa Mine.
Discovery arranged for MetSolve Labs of Langley, British Columbia, an independent arm's length laboratory, to perform metallurgical testing on intermediate-grade gold and copper mineral samples from the Willa Mine to confirm the accuracy of certain historical metallurgical test work conducted in the 1980s and in 2004 as set out in the NI 43-101 compliant Technical Report on the Willa Deposit, issued November 23, 2012 (Table 13.4, page 50). This historical metallurgical test work was based on high-grade mineralization taken from chip and muck samples from one section of the West Zone and indicated metallurgical recoveries ranging from 78.8 to 83% for gold and 86.6 to 93.9 % for copper. A Qualified Person has not done sufficient work to assess the relevance or reliability of the historic samples, or to verify the historic data or assumptions relating thereto.
For the current metallurgical test program, diamond drill core from the 2004 diamond drilling program was taken from holes drilled over a wider range of the West Zone and was broken into three categories: a) Sub-grade ($value less than $115/tonne), Intermediate-grade ($value $115 to $174/tonne) and High-grade ($175/tonne or greater). The dollar values are in Canadian funds, based on a world gold price of US$1,200/ troy oz., a copper price of US$3.00/lb., and a silver price of US$20.00/ troy oz., and taking into account internal and external mine dilution, milling recoveries of 82% for gold, 82% for silver, and 90% for copper, transport of copper concentrate, plus expected smelting and refining costs and losses, and a $Cdn at US$0.90.
The current phase of metallurgical testing of gold and copper mineral samples was conducted on the Intermediate grade mineralization in order to determine the bias, if any, in the historical test results relating to high-grade mineral samples. Discovery expected that the metallurgical recoveries from the Intermediate grade mineral would be lower than the high-grade mineral samples tested historically since generally, lower grade mineral tends to result in lower metallurgical recoveries.
The results of the most recent test current metallurgical test work on the intermediate-grade gold and copper mineral samples, however, indicated recovery of 84.7% for gold and 95.8% for copper, an increase rather than the expected decrease. Discovery believes that the increase in recoveries is due, in part, to the extraction of a gold-bearing pyrite concentrate. Discovery notes, however, that assuming the copper associated with the pyrite concentrate cannot be recovered, the overall recovery of copper would drop to the range of 90 to 92%.
Recovery of the gold-bearing pyrite concentrate resulted in an extremely low sulfide content in the final tailings, a condition seldom met in other tailings deposits.
The sampling was restricted to the diamond drill core recovered from the 2004 drill program, since core from earlier drilling was not available (as discussed in Section 11.4 of the Ni 43-101 Technical Report). The sampling was restricted to the ten holes drilled on the West Zone. In total, 96 only, 2-metre samples were recovered for the test work, including:
- 28 of Sub-grade averaging 1.98 g Au/t, 0.39% Cu and 6.3 g Ag/t ($Cdn value $85/t),
- 29 of Intermediate grade averaging 3.40 g Au/t, 0.60% Cu, and 8.6 g Ag/t ($Cdn Value $143/t)
- 36 of High grade averaging 9.69 g Au/t, 1.27% Cu, and 27.9 g/t Ag ($Cdn Value $389/t)
The total overall weight to the samples was 295 kg.
The QP personally recovered and logged the samples from the core boxes, bagged and labelled them, and transported them directly to MetSolve, where the samples were categorized and combined into the three grade categories.
To date, the work was restricted to the Intermediate grade category.
The next tests will be conducted on the High grade category of samples, followed by tests on the sub-grade category.
The current test work indicates the tailings discharged to the tailings pond will contain extremely low sulfide content, a condition seldom met by other mining operations.
The tailings effluent toxicity was tested on daphnia magna and surpassed the government regulation requirement of a 50% survival rate.
Akash Patel, Discovery's current President and CEO stated, "We are encouraged by these results. These findings signal a positive outlook for our company's WillaMax project's production potential."
The scientific and technical disclosure in this press release has been reviewed and approved by Wayne Ash, P.Eng., an engineering consultant to Discovery who is a "Qualified Person" as defined by National Instrument 43-101 for this project.