Hot Features
Premium
Trade smarter, not harder: Unleash your inner pro with our toolkit and live discussions.
Nevada Sunrise Gold Corporation (TSX-V:NEV) is pleased to announce that Pilot Gold Inc. (TSX:PLG) has reported results from an initial metallurgical program designed to address the amenability of high-grade mineralization from the Secret Canyon host rock to produce a high-grade concentrate at the Kinsley Mountain project.
Kinsley Mountain is a joint venture between Pilot Gold and Nevada Sunrise. Pilot Gold holds a 79.1 per cent interest in Kinsley Mountain, and Nevada Sunrise, through a wholly-owned U.S. subsidiary, holds a 20.9 per cent interest.
Pilot Gold reports that the initial metallurgical test results demonstrate that high-grade sulphide mineralization from the Western Flank zone can produce a high-grade concentrate with excellent gold recoveries, at potentially low capital and operating costs.
At Kinsley Mountain, initial geochemical analyses of mineralized intercepts, including characterization of carbon and sulfur, ICP analysis and determination of the solubility of gold in cyanide demonstrated that the concentration of gold relative to sulfur is high relative to other sediment-hosted, Carlin-style gold deposits. As well, petrographic work showed that pyrite, within which the gold is believed to be resident, is relatively crystalline, dense (non-porous) and that there is a very small quantity of sulfides that are <20 microns. These data and observations demonstrate potential for producing a high-grade flotation concentrate, which could then be evaluated for direct sale to commercial smelters or potentially to any one of several Nevada mine operators who can process refractory concentrates via roasting or autoclaving, for final recovery of the gold.
Four samples representing a range of gold grades from 4.23 to 20.3 g/t gold and a range of cyanide solubility levels were subjected to rougher and scavenger flotation testing over a range of conditions including variations in grind size, followed by cyanidation of the flotation tails. Combined concentrate recoveries ranged from a low of 76% to a high of 89.6%. Combined with cyanidation of the flotation tails, the total recovery increased to 89.0% to 95.0%. The concentrate grades ranged from a low of 98.6 g/t gold to a high of 312 g/t gold, with gold recovery to concentrate highest in the higher-grade and less oxidized samples.
Secret Canyon gold mineralization at Kinsley Mountain, unlike more typical Carlin-style deposits, is unique in several aspects:
1. The sulfides at Secret Canyon are crystalline, dense (not porous) and the lack of sulfides <20 microns make them prime candidates for flotation.
2. The total sulfide sulfur content of Secret Canyon material averages about 1.0%, which is low for a typical Nevada refractory resource, indicating that flotation concentration ratios can be high and consistently produce high grade concentrates.
3. The ratio of gold, in grams/tonne – to sulfide sulfur, in percent (Ratio: Au/S) is very high, ranging from 7.8 to 19.2 for the four Master Composites. Since refractory gold treatment facility capital and operating cost are most affected by sulfide sulfur content, the low sulfide sulfur feed grade and the high ratio of Au/S are very favourable indicators for:
a. Low capital cost facilities for on-site treatment,
b. Low relative operating cost for concentrate treatment whether processed on or off-site by other commercial entities.
4. Concentrate grade ranged from 98.6 to 312 g/t gold. At a US$1,200 gold price, the contained value of these concentrates range from $3,800 – $12,000 per tonne. Therefore, cost for on-site processing or shipping and processing concentrate at a commercial smelter or a local Nevada refractory treatment facility would only represent a small portion of the overall concentrate value.
Concentrates were assayed for deleterious elements and were found to contain arsenic and antimony. Arsenic in the concentrate tested ranged from 0.69% to 1.22% and averaged 1.01% while antimony in the concentrate tested ranged from 0.022% to 1.58% and averaged 0.60%. While arsenic and antimony are elevated, the levels would not preclude direct sale to a smelter, sale to a concentrate blender or to a typical Nevada refractory ore processing facility.
The program was carried out at Hazen Research, Inc. in Golden, Colorado under the direction of consulting metallurgist Gary Simmons. Mr. Simmons has more than 35 years of experience with mining companies in project management, process development, mill operations, design engineering, research and development and corporate due diligence. He played key roles with Fronteer Gold on the Long Canyon and Northumberland projects, and was Senior Technical Director, Metallurgy and Technology for Newmont Mining Corporation.
