Western Exploration Reports Average of 69.3% Gold Extraction from First Round of Metallurgical Test Work at Doby George, Aura Project, NV
- Positive test results from metallurgical heap leach program at Doby George
- Gold extraction of oxide mineralization averaged 69.3%
- Low reagent consumption for commercial heap leaching
- None.

Figure 1. Plan view map showing location of Doby George drill holes for composite bottle roll results listed in Table 1, and highlighting assays reported in Western Exploration's news releases dated, October 26, 2022, December 8, 2022 and January 17, 2023. (Graphic: Business Wire)
Highlights:
- Agitated cyanidation bottle roll test work was completed on 46 composites generated from samples collected during the 2022 PQ drill program completed in 2022 (refer to Table 1 and Figure 2 for detailed test results).
-
The composites ranged in grade from 0.17 g/t Au 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% (see news release of January 17, 2023). -
Average gold extraction of oxide mineralization of
69.3% from the agitated cyanidation bottle roll leach test work. -
The oxide composites generally did not contain detectable sulfur and composites from West Ridge Deep (Mixed) only contained approximately
0.07% to0.2% sulfide sulfur. - Reagent consumption was consistently low and is expected to be low for commercial heap leaching, averaging 0.12 kg/ton for cyanide and 0.9 kg/ton for lime.
Western Exploration CEO, 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 407k Gold ounces in the indicated category (12.9k tonnes at 0.98 g/t) and 119k Gold ozs in the inferred category (4.99k tonnes at 0.73 g/t).
"The metallurgical test results that support heap leach gold recoveries of approximately
Table 1. Summary Results of Bottle Roll Tests at Doby George Variability Composites(1) |
||||||||||
|
|
Number
|
|
|
Average
|
|||||
|
Drill |
Au Recovery % |
Head Grade, gAu/mt |
Consumed,
|
||||||
Description |
Holes |
Average |
Min. |
Max. |
Average |
Min. |
Max. |
NaCN |
Lime |
|
West Ridge Oxide |
DGC789 |
8 |
76.0 |
50.0 |
85.4 |
2.36 |
0.12 |
6.36 |
0.14 |
0.7 |
DGC790 |
7 |
68.1 |
50.4 |
76.1 |
2.48 |
1.25 |
4.05 |
0.12 |
0.6 |
|
DGC791 |
13 |
70.3 |
60.0 |
84.3 |
2.03 |
0.50 |
4.27 |
0.11 |
0.6 |
|
All |
28 |
71.4 |
50.0 |
85.4 |
2.24 |
0.12 |
6.36 |
0.12 |
0.6 |
|
West Ridge Deep Oxide |
DGC796 |
1 |
68.2 |
68.2 |
68.2 |
1.57 |
1.57 |
1.57 |
0.12 |
0.6 |
West Ridge Deep Mixed |
DGC796 |
2 |
16.7 |
1.4 |
31.9 |
2.06 |
1.39 |
2.73 |
0.20 |
0.6 |
Daylight Oxide |
DGC792 |
5 |
69.3 |
35.0 |
85.8 |
2.58 |
0.61 |
5.20 |
0.10 |
1.8 |
DGC793 |
4 |
54.5 |
20.5 |
81.6 |
1.30 |
0.44 |
2.34 |
0.12 |
1.7 |
|
All |
9 |
62.7 |
20.5 |
85.8 |
2.01 |
0.44 |
5.20 |
0.11 |
1.7 |
|
Twilight Oxide Mixed |
DGC794 |
3 |
66.9 |
60.5 |
77.4 |
5.40 |
2.28 |
9.38 |
0.11 |
1.1 |
DGC795 |
3 |
71.8 |
63.8 |
82.1 |
1.47 |
0.56 |
2.29 |
0.10 |
0.9 |
|
All |
6 |
69.3 |
60.5 |
82.1 |
3.43 |
0.56 |
9.38 |
0.11 |
1.0 |
|
All Composites |
All |
46 |
67.0 |
1.4 |
85.8 |
2.33 |
0.12 |
9.38 |
0.12 |
0.9 |
Note: | ||
(1) |
Bottle roll cyanide leach test was conducted on each composite at an |
The Doby George variability composites were amenable to agitated cyanidation treatment at the
Gold recoveries obtained from the West Ridge Oxide samples from drill holes DGC789, 790 and 791 ranged from
Gold recoveries from the Daylight oxide composites averaged
Gold recoveries from the Twilight oxide and mixed composites were similar. Gold recoveries from the Twilight samples ranged from
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
A copy of the Technical Report is available on SEDAR (www.sedar.com) 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, totaling 116,355 meters of drilling. This includes 83 drill holes totaling 23,760 meters 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 favorable 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 seventy percent can be expected via a crush of 1 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 ("NI 43-101")), the Aura Project has well established infrastructure including year-round accessibility by highway and county-maintained road and nearby access to water and electricity (see Figure 4 below). 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 (see Table 2 below).
Table 2. Updated mineral resource estimates for the Aura Project (October 21, 2021 Technical Report).
MINERAL RESOURCE ESTIMATE(1) |
||||||||||||||
|
Indicated |
Inferred |
||||||||||||
Tonnes |
Au
|
Au
|
Ag
|
Ag
|
AuEq
|
AuEq
|
Tonnes |
Au
|
Au
|
Ag
|
Ag
|
AuEq
|
AuEq
|
|
Doby George(2) |
12,922,000 |
0.98 |
407,000 |
- |
- |
0.98 |
407,000 |
4,999,000 |
0.73 |
118,000 |
- |
- |
0.73 |
118,000 |
Wood Gulch(3) |
- |
- |
- |
- |
- |
- |
- |
4,359,000 |
0.66 |
93,000 |
5.80 |
808,000 |
0.74 |
104,543 |
Gravel Creek(4) |
1,315,000 |
4.73 |
200,000 |
75.0 |
3,169,000 |
5.81 |
245,271 |
2,744,000 |
4.16 |
367,000 |
60.20 |
5,307,000 |
5.02 |
442,814 |
TOTAL |
14,237,000 |
1.33 |
607,000 |
75.0 |
3,169,000 |
1.43 |
652,271 |
12,102,000 |
1.48 |
578,000 |
15.74 |
6,115,000 |
1.71 |
665,357 |
Notes: | ||
(1) |
Au equivalent oz assumes |
|
(2) |
Pit constrained 0.2 g/t AuEq cutoff for oxide, 0.4 g/t Au cutoff for mixed and 1.4 g/t Au cutoff for unoxidized. |
|
(3) |
Pit constrained 0.2 g/t AuEq cutoff. |
|
(4) |
3.0 g/t Au cutoff. |
About Western Exploration
Born from a 25-year history of advancing exploration projects in
Test Procedure, Sample Preparation, and Quality Assurance
All samples were prepared and analyzed by McClelland Laboratories Inc.,
Direct agitated cyanidation bottle roll tests were conducted on each of the 46 variability composites at an
Leaching was conducted by rolling the pulps in bottles on the laboratory rolls for 96 hours. Rolling was suspended briefly after 2, 6, 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 A.A. methods. Pregnant solution volumes were measured and sampled. Free cyanide concentration and pH were determined for each pregnant solution. Make-up 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 (2 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
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.
For additional information on the Aura Project, please see the Technical Report, which has been prepared in accordance with the requirements of NI 43-101, a copy of which is available on SEDAR (www.sedar.com) under Western Exploration's issuer profile and on Western Exploration's corporate website (www.westernexploration.com).
Cautionary Statements Regarding Estimates of Mineral Resources
This news release uses the terms measured, indicated and inferred mineral resources as a relative measure of the level of confidence in the resource estimate. Readers are cautioned that mineral resources are not mineral reserves and that the economic viability of resources that are not mineral reserves has not been demonstrated. The mineral resource estimate disclosed in this news release may be materially affected by geology, environmental, permitting, legal, title, socio-political, marketing or other relevant issues. The mineral resource estimate is classified in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum's "CIM Definition Standards on Mineral Resources and Mineral Reserves" (CIM) incorporated by reference into NI 43-101. Under NI 43-101, estimates of inferred mineral resources may not form the basis of feasibility or pre-feasibility studies or economic studies except for preliminary economic assessments. Readers are cautioned not to assume that further work on the stated resources will lead to mineral reserves that can be mined economically.
Inferred mineral resources have a great amount of uncertainty as to their existence and as to whether they can be mined legally or economically. On October 31, 2018, the SEC adopted new mining disclosure rules ("S-K 1300") that are more closely aligned with current industry and global regulatory practices and standards, including NI 43-101, although there are some differences in the two standards. Accordingly, information concerning mineral deposits contain in this release may not be comparable with information made public by
Cautionary Note Regarding Forward-Looking Information
This news release may contain "forward-looking information" and "forward-looking statements" within the meaning of the applicable Canadian and
For additional information with respect to these and other factors and assumptions underlying the forward‐looking statements and forward-looking information made in this news release concerning Western Exploration, see the management information circular dated November 12, 2021, available electronically under Western Exploration's issuer profile on SEDAR (www.sedar.com). The forward-looking statements set forth herein concerning Western Exploration reflect management's expectations as at the date of this news release and are subject to change after such date. Western Exploration disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, other than as required by law.
Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this news release. No stock exchange, securities commission or other regulatory authority has approved or disapproved the information contained herein.
View source version on businesswire.com: https://www.businesswire.com/news/home/20230710780536/en/
Darcy Marud
Chief Executive Officer
Telephone: (775) 329-8119
Email: dmarud@westernexploration.com
Nichole Cowles
Investor Relations
Telephone: (775) 240-4172
Email: nicholecowles@westernexploration.com
Source: Western Exploration Inc.
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