Mount Hope Hits 98% Gold Recovery With Simple Processing Route at Mt Solitary
Mount Hope hits +98% gold recovery in maiden Mt Solitary metallurgy
Mount Hope Mining has reported an indicative combined gold recovery of +98% via a conventional gravity and cyanidation (CIL) flowsheet at its 100%-owned Mt Solitary Gold Prospect in the Cobar Basin, NSW. The result comes from Phase 1 metallurgical testwork completed by independent laboratory ALS Metallurgy (Burnie, Tasmania) on a composite sample grading 21.4 g/t Au.
The testwork confirms that gold at Mt Solitary is coarse, free-milling and highly amenable to a simple, conventional processing route. These results materially de-risk the processing pathway as the company advances toward a maiden Mineral Resource Estimate. Approximately 70.4% of contained gold is recoverable through gravity concentration alone, while 94.6% of the remaining gold in gravity tailings is readily cyanide-soluble.
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The results that de-risk the processing story
The Phase 1 programme returned a suite of metallurgical characteristics that support a low-complexity, conventional processing flowsheet:
| Metric | Result | Why it matters |
|---|---|---|
| Combined gold recovery | +98% (98.4%) | Conventional low-cost flowsheet |
| Gravity-recoverable gold (GRG) | 70.4% | ~Three-quarters recoverable by gravity alone |
| Cyanide solubility of gravity tails | 94.6% | Remainder readily leachable |
| Gravity concentrate grade | 9,890 g/t Au at 94% recovery (coarse fraction) | Saleable-grade product |
| Bond ball mill work index | 13.1 kWh/t (medium/low hardness) | Conventional, low-cost comminution |
| Refractory gold | Negligible (~5% sulphide, 0.4% silicate) | No significant refractory behaviour |
Visual confirmation of free gold was obtained across all size fractions:
- Coarse, visible free gold detected across all size fractions (~20–600 µm)
- Native gold (Au–Ag alloy) confirmed as the dominant gold-bearing phase
- Composite head grade of 21.4 g/t Au
Fergus Kiley, Managing Director & CEO
“These are outstanding Phase 1 metallurgical results for Mt Solitary. They confirm what the visible gold observed in our drill chips and our earlier cyanide-solubility testwork indicated, that Mt Solitary hosts a clean, coarse-grained, free-milling gold system that responds exceptionally well to conventional gravity and cyanidation processing.”
What “free-milling” gold means for investors
Free-milling gold refers to gold that can be extracted using conventional gravity and cyanidation methods without requiring complex pre-treatment. This contrasts with refractory ores, where gold is locked within sulphide minerals or silicate matrices and requires additional processing steps such as roasting or pressure oxidation before cyanidation. Gravity recovery physically separates dense gold particles from lighter waste rock using centrifugal force, whilst cyanidation dissolves the remaining gold into solution for recovery.
For Mt Solitary, the free-milling nature of the ore — combined with coarse, liberated gold particles — translates directly into a simpler flowsheet, lower capital requirements, and reduced processing risk. This materially strengthens the pathway to economic development.
Two decades apart, two labs reach the same conclusion
Independent historical testwork by Metcon Laboratories (1999, Report 99669) closely corroborates the 2026 results, strengthening confidence in the metallurgical characteristics of Mt Solitary mineralisation. The historical work, completed for previous tenement holders on separate RC drill composites, returned cyanide gold recoveries and gravity responses remarkably consistent with ALS Metallurgy’s 2026 findings.
| Parameter | Metcon 1999 | ALS 2026 |
|---|---|---|
| Cyanide gold recovery | 93.9% / 94.1% (whole-ore leach) | 94.6% (gravity tailings) |
| Gold to gravity | 32–40% (single-pass Knelson) | 70.4% (3-stage GRG) |
| Coarse gold observed | Flakes 1–2 mm plus abundant fine gold | Free gold to ~600 µm, all fractions |
The Metcon data is historical, has not been independently verified by Mount Hope Mining, and is provided for comparative purposes only — it should be considered indicative and not relied upon as metallurgical recovery factors.
A low-capital development path through the Cobar Basin
The demonstrated amenability of Mt Solitary mineralisation to conventional gravity and CIL processing strengthens the case for a potential low-capital development pathway. Subject to further technical, commercial and economic evaluation, the proximity of existing CIL facilities within ~200 km may provide opportunities for toll treatment or ore sale arrangements as alternatives to constructing a standalone processing facility. Three CIL-capable plants operate in the region:
- Wonawinta (Manuka Resources) — dedicated CIL facility, ~107 km north
- Peak (Aurelia Metals) — flotation plus CIL facility, ~154 km north
- Mineral Hill (Kingston Resources) — flotation plus CIL facility, ~195 km northeast
The company considers the evaluation of these options to be an important component of future project studies as it progresses resource definition and advances Mt Solitary towards a maiden Mineral Resource Estimate. The proximity of multiple operating CIL plants makes Mt Solitary potentially strategic within this regional infrastructure context and supports an expedited, lower-capital route to production.
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Next steps toward a maiden Resource
Building on these results, the company intends to progress the following work programme:
- Variability and composite metallurgical testwork across the range of mineralisation styles, oxidation states and grades at Mt Solitary to confirm the consistency of gravity recovery, cyanide leach performance and overall metallurgical response
- Collection of additional drill core to undertake further comminution characterisation, including abrasion, crushing and grinding testwork, to support process plant design and engineering studies
- Scoping-level process flowsheet development, building on the conventional gravity and CIL processing route indicated by the current metallurgical testwork
- Assessment of potential development pathways, including evaluation of regional processing infrastructure and, where appropriate, potential toll-treatment and ore sale opportunities with existing operators
- Completion of a targeted Phase 3 drilling programme to support geological interpretation and provide sufficient data for the preparation of a maiden JORC-compliant Mineral Resource Estimate for the Mt Solitary Prospect
The company has previously defined a JORC (2012) Exploration Target at Mt Solitary of 1.32–1.87 Mt at 1.0–1.35 g/t Au for 42.5–81.4 koz Au. The potential quantity and grade of the Exploration Target are conceptual in nature, and there has been insufficient exploration to estimate a Mineral Resource. It is uncertain whether further exploration will result in a Mineral Resource. Mt Solitary sits within Mount Hope Mining’s expanded MS2 Gold Corridor, a district-scale ~7.5 km mineralised trend with multiple targets and strong upside for repeat gold discoveries along strike and at depth.
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