Mount Hope Mining Reports Over 98% Gold Recovery at Mt Solitary with Positive Phase 1 Metallurgical Test Results

Initial Metallurgical Program Validates Coarse, Free-Milling Gold at Mt Solitary

Mount Hope Mining completed its first Phase 1 metallurgical testwork on a composite sample from the Mt Solitary Gold Prospect, performed by ALS Metallurgy in Burnie, Tasmania. The results confirm the gold is coarse, free-milling, and highly amenable to a conventional processing route combining gravity separation and cyanidation. This finding is crucial for project development, demonstrating technical viability with established, low-complexity methods that reduce operational and technical risks as the company advances toward resource estimation.

The master composite sample, weighing approximately 158 kilograms, was derived from reverse circulation drill samples from holes 25MSRC003 and 25MSRC004 during the Phase 1 drilling program. The sample was crushed and subdivided for head analysis, comminution testing, gravity separation, and gold deportment studies. ALS conducted comminution testing via Bond ball mill work index, gravity separation trials, mineralogical characterization using quantitative X-ray diffraction (QXRD) and TESCAN Integrated Mineral Analyser (TIMA), and diagnostic leach tests to assess processing response.

Gravity-Recoverable Gold Surpasses 70% with Excellent Cyanide Leachability

Testwork results show gravity separation recovered over 70% of the gold, with gravity concentrate upgraded to 9,890 grams per tonne at 94% recovery from the coarse fraction. Approximately 94.6% of the residual gold after gravity separation was cyanide-soluble, demonstrating strong leaching response. This two-stage recovery—gravity concentration followed by cyanidation of gravity tailings—supports the overall combined recovery rate exceeding 98% as announced.

Gold hosted in silicate minerals was minimal at 0.4%, with about 5% associated with sulphides, confirming the free-milling nature of the mineralisation and absence of refractory characteristics that could complicate processing or increase costs. The robust performance of gravity and cyanidation stages endorses a simple, low-complexity processing flowsheet, reducing metallurgical risk and supporting project progression.

Coarse Native Gold up to 600 Micrometres Detected Across Size Fractions

Automated mineralogy via TESCAN Integrated Mineral Analyser identified native gold—a gold-silver alloy with less than 15% silver—as the primary gold-bearing phase. Optical free-gold examination using a Gemini table recovered and imaged coarse native free gold across all three screened size fractions. Visible free gold ranged from roughly 20 micrometres to 600 micrometres in maximum grain size. The presence of coarse, liberated free gold is a key factor driving the strong gravity and leach responses observed.

Specifically, microscopy found one grain about 400 micrometres in the >250 micrometres fraction, five grains between approximately 150 and 600 micrometres in the 75–250 micrometres fraction, and 30 grains from about 20 to 100 micrometres in the <75 micrometres fraction. This distribution supports high gravity recovery and indicates favourable particle liberation suitable for conventional processing.

Quantitative Mineralogy Shows Silica-Rich, Oxidised Quartz-Hosted System

QXRD analysis confirmed a quartz-dominant, oxidised mineral assemblage with 69.3% quartz, 9.1% kaolinite, 8.4% hematite, and 6.6% muscovite. These results align with geological interpretations of a silicified, low-sulphur gold system hosted in sedimentary rocks. Head analysis of the composite indicated a gold grade of 21.4 grams per tonne, with silica comprising 78.2% silicon dioxide and iron 8.2%.

The quartz dominance and low sulphur content (0.14%) reinforce the free-milling nature of the mineralisation. The assemblage reflects supergene oxidation and the absence of complex copper-gold or polymetallic associations requiring specialized processing. This simplicity supports the straightforward gravity and cyanidation flowsheet and underpins confidence in conventional processing feasibility.

Bond Ball Mill Work Index Indicates Standard Comminution Needs

A Bond ball mill work index of 13.1 kWh/t classifies the Mt Solitary ore as medium hardness, implying conventional comminution and low-cost grinding. This metric is critical for project economics since comminution typically represents a major operating cost in gold processing. Medium hardness suggests standard milling equipment and grinding technology will suffice without specialized hard-rock methods.

The combination of medium hardness, free-milling gold, and strong gravity and cyanidation responses points to a simple, low-complexity processing route with moderate capital and operating costs. These characteristics align with multiple operating gold mines in the Cobar Basin, supporting evaluation of alternative development options such as toll treatment or ore purchase agreements that could avoid building a dedicated processing plant.

Metallurgical Findings Support Alternative Development Strategies Including Toll Treatment

The metallurgical outcomes positively influence Mount Hope Mining's development plans. The mineralisation’s compatibility with conventional gravity and cyanidation processing matches technologies used at several existing Cobar Basin gold operations. The company highlights that, pending further technical, commercial, and economic analysis, proximity to these facilities—within approximately 200 kilometres—offers potential for alternative development pathways, such as toll treatment, instead of constructing a standalone processing facility.

Managing Director and CEO Fergus Kiley emphasized that evaluating toll treatment and ore sale options is a key part of future project studies. This strategy could significantly lower capital expenditures and development risks by utilizing existing infrastructure. Such flexibility is integral to the company’s approach as it advances resource definition and progresses Mt Solitary toward its maiden Mineral Resource Estimate, enhancing project value by mitigating technical, financial, and execution risks.

Phase 1 Results Complement May 2026 Cyanide-Solubility Screening for Fresh and Primary Ore

The Phase 1 metallurgical results build on cyanide-solubility testing announced on 6 May 2026, which showed consistently high gold solubility in fresh mineralisation at depth. Together, these programs increase confidence that favourable metallurgical properties extend throughout the mineralised system. Consistency between near-surface oxidised and deeper fresh material suggests processing performance will be maintained with deeper mining.

This combined evidence strengthens the case for a robust, repeatable processing method applicable across different oxidation states and depths. The company plans to continue its phased metallurgical evaluation, likely including further testwork on fresh and primary ore, assessing processing variability, and engineering studies to confirm commercial-scale feasibility of the chosen flowsheet.

Mt Solitary Project Progresses Toward Maiden Mineral Resource Estimate

Mount Hope Mining is advancing the Mt Solitary Gold Prospect toward its first Mineral Resource Estimate, with Phase 1 metallurgical testwork marking a crucial milestone. The testwork confirms favourable metallurgical traits that significantly reduce risk. With gravity-recoverable gold over 70% and cyanide leaching recovering about 95% of remaining gold, the combined recovery surpassing 98% establishes a strong processing foundation.

The company’s phased approach—including drilling, metallurgical evaluation, resource estimation, and engineering studies—is designed to progressively de-risk the project. Confirmation of coarse, free-milling gold suitable for simple processing reduces technical complexity and supports future feasibility studies. Upcoming milestones likely include completing resource definition drilling, preparing the maiden Mineral Resource Estimate, conducting scoping and feasibility studies, and evaluating development pathways such as toll treatment or ore sale agreements with existing Cobar Basin operations.

Strategic Location of Mt Solitary in the Cobar Basin

Mt Solitary is situated within New South Wales’ Cobar Basin, a region known for established gold mining operations and processing infrastructure. The basin hosts several operating gold plants using gravity and cyanidation technologies, offering Mount Hope Mining potential development advantages through access to existing toll-processing facilities, supply chains, regulatory frameworks, and skilled labour.

The project’s proximity to mining services, equipment suppliers, and technical expertise in processing similar ores enhances its commercial appeal. The company’s recognition of toll treatment possibilities within 200 kilometres highlights strategic awareness of regional benefits. These factors collectively improve the economic attractiveness of Mt Solitary compared to developing an isolated operation requiring new processing and support infrastructure.