OzAurum’s Heap Leach Tests Hit 82% Gold Recovery at Mulgabbie North
OzAurum Resources reports strong metallurgical results from heap leach column tests at Mulgabbie North, confirming a low-cost production route with high gold recoveries and advancing plant commissioning despite minor delays.
- Heap leach gold recoveries up to 82%, potential 88% with finer crushing
- Low cyanide consumption suggests cost-efficient processing
- Plant refurbishment and dry commissioning nearing completion
- High-grade intercepts support scalable development along 8km shear zone
- Further drilling planned to extend mineralisation and confirm results
Heap Leach Testwork Validates Low-Cost Production Strategy
OzAurum Resources Ltd (ASX:OZM) has delivered heap leach column test results that bolster its low-capex development plan for the Mulgabbie North Gold Project in Western Australia. The standout recovery came from saprolite and transition ore crushed to -12mm, which achieved 82% gold recovery, with laboratory tests suggesting an increase to 88% if crushed finer to -8mm. This level of recovery is notable given the ore’s modest head grade of 1.35 g/t Au and supports the company’s plan to crush ore to -8mm for heap leach production.
Complementing the high recovery rates, cyanide consumption was impressively low at approximately 0.21 kg/t, less than half the typical 0.5 kg/t consumption seen in similar operations. Such efficiency points to a potentially lean operating cost profile, a critical factor for sustaining margins in gold heap leach projects.
Strong Leach Kinetics and Multiple Ore Types Tested
Column tests also demonstrated rapid leach kinetics, with over 60% of gold recovered within 25 days and more than 75% by 50 days. This rapid recovery supports shorter gold production cycles, enhancing near-term revenue potential. The third column, testing paleochannel ore crushed to -12mm, showed preliminary recoveries exceeding 75% after 39 days, though these results remain subject to further confirmation.
Importantly, heap leach amenability has been confirmed across three distinct ore types, enhancing confidence in processing flexibility. Independent metallurgical testing was conducted by ALS Balcatta under the supervision of Kappes Cassiday & Associates Australia, adding credibility to the findings.
Plant Refurbishment Progress Amid Weather Delays
On the infrastructure front, Polaris Engineering Services has completed dry commissioning of key heap leach plant modules, including the feed bin, feed conveyor, and agglomeration drum. While delays in conveyor deliveries and unseasonal rainfall have pushed back concrete foundation pours by three weeks, these issues appear manageable with foundation work expected imminently. The lime and cement silo system is reported as 95% complete, indicating the project remains on track for near-term production.
Geological Setting Supports Resource Growth Potential
The Mulgabbie North Gold Project lies along an 8km Relief Shear corridor, a major structural feature hosting continuous mineralisation. The project’s geology includes high-grade intersections associated with faults and quartz veining, with mineralisation open at depth and along strike. The presence of sandstone-hosted gold mineralisation with pyrite and arsenopyrite is comparable to nearby large deposits at Carosue Dam, operated by Northern Star Limited. This geological continuity underpins the company’s plans for further drilling aimed at resource expansion.
OzAurum’s Managing Director Andrew Pumphrey highlighted that the heap leach results across all geological domains provide confidence in advancing the project as a long-life, low-cost gold operation. With commissioning of the first four plant modules complete, the company is optimistic about moving toward production.
Bottom Line?
OzAurum’s heap leach test results reinforce a cost-effective production pathway at Mulgabbie North, but confirmation of preliminary data and timely plant commissioning remain key to unlocking value.
Questions in the middle?
- Will further metallurgical testing confirm the preliminary paleochannel recovery rates?
- How will recent weather-related delays impact the production timeline?
- Can ongoing drilling expand the resource beyond the current 260,000 oz estimate?
