Otis Gold Corp.: Kilgore Project Achieves >92% Gold Recoveries
08.01.2020 | GlobeNewswire
VANCOUVER, Jan. 08, 2020 - Otis Gold Corp. (“Otis” or the “Company”) (TSX-V: OOO) (OTC: OGLDF) is pleased to announce up to 92.6% gold recovery from column leach metallurgical testing of near-surface mineralized volcanic rock at its Kilgore Project. The test samples came from drill hole 17OKC-379, a larger diameter PQ drill hole that contained a true width interval of 120 feet (35.6 metres) with a calculated head grade of 1.49 g/t Au; the PQ core hole was a twin of 17OKC-356.Highlights:
- Gold extraction of 92.6% on half-inch (0.5”) crush columns over 200 days (see Figure 1).
- Gold extraction of 85.9% on one and a half-inch (1.5”) crush columns over 200 days.
- Gold extraction of 56.1% on three-inch (3.0”) crush columns. The three-inch column was terminated after 120 days once no further gold extraction was recorded.
- Finer crush sizes improved the gold extraction rate, reaching 60% gold extraction in approximately 24 days (0.5”) versus 56 days at the next coarser crush size (1.5”).
- Notable was that at 0.5” and 1.5” crush sizes gold recoveries had not plateaued after 200 days.
- Gold recoveries for 0.5” crush and simulated 3.0” Run-of-Mine (ROM) mineralized material processing are significantly higher than the respective 82% and 50% recoveries used in the Kilgore Preliminary Economic Assessment (see Otis News Release dated August 27, 2019).
- Silver was also recovered during all phases of testing. Column leach extractions were 41.9%, 37.2% and 17.4% respectively (see Table 1), indicating that additional work is required to assess silver’s potential impact on Kilgore’s economics.
| Table 1: Summary of Column Leach Results | ||||||||
| Crush Size | Extraction % | Residue Assay | Calc. Head | NaCN Consumption (kg/t) | Lime Consumption (kg/t) | |||
| Au | Ag | Au (g/t) | Ag (g/t) | Au (g/t) | Ag (g/t) | |||
| 0.5" | 92.6 | 41.9 | 0.111 | 1.3 | 1.493 | 2.2 | 4.664 | 4.561 |
| 1.5" | 85.9 | 37.2 | 0.143 | 1.8 | 1.012 | 1.8 | 3.260 | 1.276 |
| 3.0" | 56.1 | 17.4 | 0.313 | 2.1 | 0.713 | 2.5 | 2.362 | 1.121 |
Otis submitted approximately 450kg of PQ core from drill hole 17OKC-379 to Resource Development Inc. of Denver, CO for metallurgical testing. The drill samples to be tested came from the interval: 13ft (4.0m) to 133ft (40.5m), an interval of 120ft (35.6m), and returned head assays of 1.49 g/t Au and 2.2 g/t Ag, including 5ft (1.52m) from 119ft to 124ft (36.3-37.8m) of 42.68 g/t Au and 15 g/t Ag. These assays are significantly higher than those from the original, smaller diameter, HQ core hole 17OKC-356 which returned a mineralized interval of 124ft (37.8m) averaging 0.31 g/t Au; the difference in returned gold values highlighting the variable nature of gold mineralization at Kilgore. The samples, as analyzed in both holes, came from near surface, hydrothermally altered and oxidized rhyolite-composition lithic tuffs.
Metallurgical testing of the samples consisted of:
- Initial head grade assay of each of the drill intervals submitted
- Bench-top bottle roll leach tests
- Column leach tests at 0.5-inch, 1.5-inch and 3.0-inch crush sizes
The test work was conducted to confirm the suitability of this material to treatment by cyanide heap leaching and to validate the crush size required for efficient gold extraction. Each of the tests was conducted in a typical heap leach configuration. Mineralogical examination of the higher-grade gold occurrences within the samples submitted revealed gold grains associated with Jarosite, a mineral product of oxidation of iron sulfides, varying in size from <2 microns to 70 microns (Figure 2).
Alan Roberts, Vice President of Explorations, stated: “The improvement in recovery revealed by this round of metallurgical testing shows the amenability of the Kilgore Deposit to heap leach gold and silver recovery; both the gold recoveries for 0.5” crush and simulated 3.0” Run-of-Mine mineralized material processing are significantly higher than the respective 82% and 50% recoveries used in our recently-released Preliminary Economic Assessment. Furthermore, the identification of the direct association between Gold and jarosite is an important step in understanding the nature and character of mineralization at Kilgore.”
Alan Roberts, MSc, CPG (AIPG: CPG#11260), Vice President of Exploration, is the Qualified Person for this news release and has reviewed and approved the technical content contained herein.
About the Kilgore Project
The Kilgore Project has a current NI 43-101 Indicated Resource of 825,000 ounces Au in 44.6 million tonnes at a grade of 0.58 g/t Au and an Inferred Resource of 136,000 ounces Au in 9.4 million tonnes at a grade of 0.45 g/t Au. The maiden Preliminary Economic Assessment (or “PEA”) showed an after-tax NPV (5% discount rate) of US$110.4 million and IRR of 34.0%, with a 3-year payback period and LOM net cash flow of US$151.8 million at a $1,300 gold price. Please note the PEA is preliminary in nature and includes Inferred resources that are too speculative geologically to have the economic considerations applied to them. There is no certainty that the PEA will be realized. Mineral resources that are not mineral reserves do not have demonstrated economic viability.
About the Company
Otis is a resource company focused on the acquisition, exploration, and development of precious metal deposits in Idaho, USA. Otis is currently developing its flagship property, the Kilgore Project, located in Clark County, Idaho and the Oakley Project, located in Cassia County, Idaho.
ON BEHALF OF THE BOARD
“Craig T. Lindsay”
President & CEO
For additional information, please contact:
Otis Gold Corp.
Mr. Tony Perri – Corporate Development
Tel: (604) 424-8100
Email: tony@otisgold.com
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