Panther Metals completed all six batches of Vibracore assay results for the Winston Lake Mine tailings storage facility (TSF) in May 2026. The historic Winston Lake Mine processed ~3.3 million tonnes of ore from 1988–1998, and it is believed a significant quantity of gold, silver, zinc, copper, cobalt, and gallium remains in the TSF. The 109-hole Vibracore grid confirmed average tailings depth of 8.7m (max 16.8m). This calculator models potential in-situ and recoverable value ahead of the Mineral Resource Estimate (MRE).
Batch-by-batch assay summary — peak reported grades
| Batch / Date |
Au (g/t) |
Ag (g/t) |
Zn (%) |
Cu (%) |
Co (ppm) |
Ga (ppm) |
| Prelim · Jul 2025 | 0.814 | 21.9 | 2.20 | 0.20 | 496 | 122 |
| Batch 1 · Mar 2026 (avg: 22 samples) | 0.529 | 12.6 | 1.46 | 0.133 | 320 | 93 |
| Batch 2 · Mar 2026 (avg: 32 samples) | 0.532 | 12.1 | 1.36 | 0.122 | 307 | 88 |
| Batch 3 · Apr 2026 (avg: 76 samples) | 0.485 | 11.9 | 1.38 | 0.131 | 296 | 86 |
| Batch 4 · Apr 2026 (avg: 115 samples) | 0.494 | 11.6 | 1.25 | 0.122 | 291 | 87 |
| Batch 5 · May 2026 (avg: 106 samples) | 0.434 | 10.0 | 1.42 | 0.129 | 274 | 84 |
| Batch 6 · May 2026 Final (avg: 127 samples) | 0.483 | 11.6 | 1.29 | 0.131 | 311 | 87 |
| All Batches Combined (478 samples) | 0.481 | 11.4 | 1.34 | 0.128 | 296 | 87 |
Adjust assumptions
Valuation results
⚠ At this grade and price combination, margins are thin. A higher grade or recovery assumption is needed for robust economics.
✕ Recoverable value is below typical reprocessing opex thresholds. Consider increasing grade, recovery, or commodity price inputs.
In-situ gross value
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Before recovery / costs
Recoverable value
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After metallurgical recovery
Value per tonne
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Recovered $/t tailings
Au contribution
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% of recoverable value
Zn contribution
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% of recoverable value
Au oz contained
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In-situ gold ounces
Total recoverable in-situ value
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Metal-by-metal breakdown (recoverable)
Sensitivity — impact per unit change
Per 0.01 g/t Au shift
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recoverable value impact
Per 1m depth shift
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recoverable value impact
Per $100 Au price shift
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recoverable value impact
Context
| Winston Lake Mine operational period | 1988 – 1998 |
| Ore processed (historical) | ~3.3 Mt |
| Vibracore holes drilled | 109 holes |
| Avg confirmed tailings depth | 8.7 m |
| Max confirmed tailings depth | 16.8 m |
| Metals confirmed in TSF | Au, Ag, Zn, Cu, Co, Ga, In |
| Metallurgical testwork contractor | Extrakt Process Solutions |
| Recovery permit pathway | Ontario July 2025 regulation |
| Peak Au grade reported (preliminary) | 0.814 g/t |
| Peak Zn grade reported (preliminary) | 2.20% |
| Site infrastructure | Grid power, water treatment, roads |
| Existing Winston Project MRE (underground) | 2.07 Mt @ 17.9% Zn (Indicated) |
Important disclaimer. This calculator is a sensitivity model for illustrative and discussion purposes only. It is not financial advice, an investment recommendation, or a formal mineral resource estimate. All output values are speculative and depend entirely on assumptions. Grade inputs represent indicative averages derived from Batches 1–6 peak assay data; true average grades across the full TSF will only be established by the MRE. No formal MRE exists for the Winston Lake tailings. Tonnage, grade, recovery rate, and commodity price assumptions are all uncertain. Recoveries are illustrative pending metallurgical testwork by Extrakt Process Solutions. Commodity prices as of May 2026 may not persist. This information should not be used as the sole basis for any investment decision. Always conduct your own research and consult a qualified financial adviser.