Mr. Darcy Marud reports
WESTERN EXPLORATION REPORTS AVERAGE OF 69.3% GOLD EXTRACTION FROM FIRST ROUND OF METALLURGICAL TEST WORK AT DOBY GEORGE, AURA PROJECT, NV
Western Exploration Inc. has released the results from its continuing metallurgical heap leach test program designed to determine the processing characteristics at Doby George. Bottle roll recoveries from the various crush sizes sampled returned positive results that will form the basis for compositing mineralization for additional column leach test work at Doby George.
Agitated cyanidation bottle roll test work was completed on 46 composites generated from samples collected during the 2022 PQ drill program completed in 2022.
The composites ranged in grade from 0.17 gram per tonne gold to 9.38 g/t Au and averaged 2.36 g/t Au and cyanide soluble gold-to-fire assay ratios (CN/FA) were generally above 80 per cent (see news release of Jan. 17, 2023).
Average gold extraction of oxide mineralization of 69.3 per cent from the agitated cyanidation bottle roll leach test work.
The oxide composites generally did not contain detectable sulphur and composites from West Ridge-Deep (mixed) only contained approximately 0.07 per cent to 0.2 per cent sulphide sulphur.
Reagent consumption was consistently low and is expected to be low for commercial heap leaching, averaging 0.12 kilogram/ton for cyanide and 0.9 kg/ton for lime.
Western Exploration chief executive officer Darcy Marud commented: "It's an exciting time for the Doby George deposit following our exploration success in 2022. In 2022, the exploration team drilled nine holes with the goal of further delineating and advancing the existing mineral resource at the Aura project. Doby George hosts 407,000 gold ounces in the indicated category (12,900 tonnes at 0.98 g/t) and 119,000 gold oz in the inferred category (4,990 tonnes at 0.73 g/t).
"The metallurgical test results that support heap leach gold recoveries of approximately 70 per cent are in line with the extensive historical exploration and metallurgical test results generated by previous owners of the deposit, including Atlas Corp., Homestake Mining Company and Independence Mining Company. It is anticipated that the results of the metallurgical heap leach test program will be used to support the preparation of a prefeasibility study on the Doby George deposit in 2024, pursuant to which the company expects to update its existing mineral resource estimate and underline potentially robust project economics supported by surface outcrops and the recent metallurgical test results. Doby George is a very exciting resource for Western Exploration and we still have extensive exploration upside on the property, particularly at Gravel Creek where our 2023 drill program is focused."
The Doby George variability composites were amenable to agitated cyanidation treatment at the 80-per-cent-1.7-millimetre feed size, indicating good potential for heap leach processing. The highest gold recoveries of over 70 per cent were obtained from the West Ridge oxide composites. Gold recoveries from the Twilight oxide and mixed composites were more variable, but on average were similar to those from the West Ridge oxides. Gold recoveries from the Daylight oxide composites generally were lower, at an average of approximately 62.7 per cent in gold recoveries. The two West Ridge-Deep mixed mineralization composites gave low gold recoveries (less than 32 per cent). Organic (non-carbonate) carbon content was low (0.08 per cent average) and was not correlated to gold recovery.
Gold recoveries obtained from the West Ridge oxide samples from drill holes DGC789, 790 and 791 ranged from 50 per cent to 85.4 per cent and averaged 71.4 per cent. Only four of the 28 composites gave gold recoveries below 65 per cent. A single West Ridge-Deep oxide composite (hole DGC796) was tested. Gold recovery from that composite (68.2 per cent) was comparable with the other oxide composites. The two mixed composites from the same drill hole gave low recoveries.
Gold recoveries from the Daylight oxide composites averaged 62.7 per cent. The reasons for the variability in gold recovery for this material are not yet understood. The composites that gave low gold recoveries also had relatively low ratios of cyanide soluble gold-to-fire assay ratios (CN/FA). These data indicate that gold recoveries from the low-recovery Daylight oxide samples may not be substantially improved by grinding before leaching.
Gold recoveries from the Twilight oxide and mixed composites were similar. Gold recoveries from the Twilight samples ranged from 60.5 per cent to 82.1 per cent and averaged 69.3 per cent.
Reagent consumptions were consistently low and are expected to be low for commercial heap leaching. Cyanide and lime consumption for all tests averaged 0.12 kg/mt and 0.9 kg/mt, respectively.
About Doby George
Doby George is one of the highest-grade undeveloped open-pit heap leach resources in Nevada and one of three mineral deposits on Western Exploration's 100-per-cent-owned Aura project. The Aura project is located 32 kilometres north of the Jerritt Canyon mine, which has been in continual operation since 1981. The deposit is an outcropping, high-grade, sediment-hosted mineral deposit, with multiple zones of mineralization identified by drilling in a 1.7 by 0.8 km area. The zone of oxidation extends 150 to 200 metres below surface, while limited deep drilling has encountered unoxidized gold mineralization at depths of over 600 metres below surface. Additional information about the Aura project is included in the technical report titled "2021 Updated Resource Estimates and Technical Report For the Aura Gold-Silver Project, Elko County, Nevada" dated Oct. 20, 2021 (with an effective date of Oct. 14, 2021).
A copy of the technical report is available on SEDAR under Western Exploration's issuer profile.
Homestake Mining Company initially discovered the deposit in the mid-1980s. Since that time, 836 drill holes have been completed, totalling 116,355 metres of drilling. This includes 83 drill holes totalling 23,760 metres that were drilled by Western Exploration LLC between 1998 and 2022. Metallurgical test work completed on oxidized material by Homestake Mining Company, Independence Mining Company and Atlas Precious Metals Inc. has indicated favourable metallurgy for standard cyanide heap leach processing. Results from the previous metallurgical testing completed on 52 bottle rolls and 23 column leach samples indicate that heap leach gold recoveries approaching 70 per cent can be expected through a crush of one to 1.5 inches.
In addition to an established mineral resource estimate (as determined in accordance with National Instrument 43-101 -- Standards of Disclosure for Mineral Projects), the Aura project has well-established infrastructure, including year-round accessibility by highway and county-maintained road and nearby access to water and electricity. Western Exploration has exploration, development and mining rights on 930 hectares of privately owned fee lands through a mineral lease agreement with a local landowner and may purchase those fee lands at any time for the development of Doby George.
The 6,000-hectare Aura project has identified mineral resources in three different deposits (Doby George, Gravel Creek and Wood Gulch), as supported by the technical report.
About Western Exploration
Born from a 25-year history of advancing exploration projects in Nevada as a private company, today Western Exploration is composed of an experienced team of precious metals experts that aims to lead Western Exploration to becoming a premiere gold and silver development company in North America. The company's principal asset is the 100-per-cent-owned Aura gold-silver project, located approximately 120 kilometres/75 miles north of the city of Elko, Nev., and includes three unique gold and silver deposits: Doby George, Gravel Creek and Wood Gulch.
Test procedure, sample preparation and quality assurance
All samples were prepared and analyzed by McClelland Laboratories Inc., Reno, Nev. Agitated cyanidation bottle roll tests were conducted on a total of 46 drill core composites from the Doby George deposit to obtain preliminary information regarding heap leach amenability and ore variability. The composites were prepared from eight PQ drill core holes (DGC-789 through DGC-796). Composites were selected based on drill hole location and depth, sample oxidation, lithology, grade, and CN/FA ratio, and each comprised 2.4 to 6.6 metres of continuous drill core. Most (42 of 46) of the composites represented oxide mineralization. Four composites (two each from West Ridge-Deep and Twilight) represented mixed mineralization.
Direct agitated cyanidation bottle roll tests were conducted on each of the 46 variability composites at an 80-per-cent-1.7-millimetre feed size. Bottle roll test ore charges were mixed with water to achieve 40-per-cent solids (wt/wt). Natural pulp pHs were measured. Hydrated lime was added to adjust the pH of the pulps to 11 before adding the cyanide. Sodium cyanide, equivalent to one gram NaCN/litre solution, was added to the alkaline pulps.
Leaching was conducted by rolling the pulps in bottles on the laboratory rolls for 96 hours. Rolling was suspended briefly after two, six, 24, 48 and 72 hours to allow the pulps to settle so samples of pregnant solution could be taken for gold and silver analysis by atomic absorption methods. Pregnant solution volumes were measured and sampled. Free cyanide concentration and pH were determined for each pregnant solution. Makeup water, equivalent to that withdrawn, was added to the pulps. Cyanide concentrations were restored to initial levels. Lime was added, when necessary, to maintain the leaching pH at between 10.8 and 11.2. Rolling was then resumed.
After 96 hours, the pulps were filtered to separate liquids and solids. Final pregnant solution volumes were measured and sampled for gold and silver analysis. Final pH and cyanide concentrations were determined. Leached residues were washed, dried, weighed and assayed in triplicate to determine residual gold content.
Crushed (two mm) drill interval samples generated during interval preparation procedures were used for preparation of the variability composites. Select interval samples were combined in entirety or were each blended and split as required to obtain the necessary weight for preparation of footage-weighted composites. Each composite was stage crushed to 80 per cent-1.7 mm (100 per cent-6.3 mm) in size. Each crushed composite was blended and split using a rotary splitter to obtain one kg for a bottle roll test and triplicate 0.5 kg samples for preparation of head assay pulp samples. The 0.5 kg splits were each pulverized to greater than 95 per cent-106 microms and used for generation of head assay pulps. Each composite was assayed in triplicate using conventional fire assay fusion procedures to determine gold and silver content. Each composite was also subjected to a cyanide shake analysis, carbon and sulphur speciation analyses. and a multielement inductively coupled plasma scan.
Qualified person approval
The scientific and technical content in this news release has been reviewed and approved by Mark Hawksworth, general manager of the Aura project and a qualified person within the meaning of NI 43-101.
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