Norwest Minerals reports strong metallurgical results from Bulgera, with gold recoveries up to 92% on coarse crushed samples, supporting a low-cost heap leach development pathway.
- High gold recoveries of 86%–92% from coarse crushed oxide and transition samples
- Rapid leach kinetics achieved within 72 hours with low reagent consumption
- Column leach testwork underway to refine heap leach design and costs
- 2026 Mineral Resource Estimate increases to 23.8Mt at 0.65 g/t for 501,000 ounces
- Orelogy Mining Consultants appointed to lead Bulgera Heap Leach Scoping Study
Strong Metallurgical Results Bolster Low-Cost Heap Leach Potential
Norwest Minerals Limited (ASX:NWM) has delivered a critical boost to its Bulgera Gold Project with metallurgical testwork revealing gold recoveries between 86% and 92% from coarse crushed oxide and transition samples. The bottle roll tests, conducted by ALS Laboratories, demonstrated not only high recoveries but also rapid leach kinetics, achieving 75% to 80% of gold recovery within the first 72 hours, and impressively low reagent consumption averaging just 0.38 kg/t cyanide and 1.3 kg/t lime. This combination is precisely what developers seek for a commercially viable heap leach operation.
The significance of these findings lies in their validation of Bulgera’s suitability for a low-cost heap leach process, which is generally favoured for near-surface oxide deposits due to lower capital and operating costs compared to conventional milling. Norwest CEO Charles Schaus emphasised the importance of these results, noting that the data strongly reinforce the project’s development potential. With column leach testing now underway to simulate real heap conditions, the company is advancing the technical groundwork to support pad design, operating cost estimates, and metallurgical modelling.
Resource Upgrade Expands Heap Leachable Inventory
The metallurgical progress dovetails with a substantial update to Bulgera’s Mineral Resource Estimate (MRE) announced earlier this year, which now stands at 23.8 million tonnes grading 0.65 g/t gold for a total of 501,000 ounces. This represents a marked increase in tonnage compared to the previous 8.4 million tonnes at 1.07 g/t, reflecting a strategic lowering of the cut-off grade from 0.6 g/t to 0.24 g/t to align with heap leach economics. Notably, 71% of the near-surface oxide and transition material, key feedstock for heap leaching, is classified in the higher confidence Indicated category, amounting to 6.06 million tonnes at 0.62 g/t for 121,000 ounces.
This resource expansion follows a series of drilling campaigns extending mineralisation continuity and depth, including the 2025 Phase 1 and 2 RC programs. The updated MRE and metallurgical testwork collectively underpin the project's dual focus on near-term cashflow through heap leach development and longer-term resource growth at depth. The recent drilling results and resource upgrade build on the momentum seen in Norwest’s earlier announcements, including the 74% surge in Bulgera gold resource and strong drilling results confirming mineralisation continuity.
Scoping Study and Environmental Strategy in Motion
To capitalise on these technical advances, Norwest has appointed Orelogy Mining Consultants to lead the Bulgera Heap Leach Scoping Study. Orelogy has previously provided conceptual heap leach layouts that confirmed all operations could be housed within the historic Bulgera mining centre, an area already heavily disturbed by past mining, thus mitigating potential environmental hurdles. The scoping study will integrate the updated 2026 resource model, metallurgical data, and cost estimates to provide a comprehensive assessment of project viability. Norwest intends to release the study results once compliance with ASX Listing Rules on production targets and financial forecasts is met.
Complementing this, MBS Environmental Consultants have completed an Environmental Approvals Strategy highlighting that the proposed heap leach facility and associated infrastructure are situated within previously disturbed land, thereby reducing environmental impact. While historical mining approvals identified no major environmental issues, updates will be required to meet current regulatory standards.
Next Steps in Metallurgical Validation and Resource Development
Column leach testing, which simulates full-scale heap leach conditions by stacking crushed ore in vertical columns and irrigating with leach solution over months, is underway at ALS Laboratories. These tests are critical to confirm that the high recoveries observed in bottle roll tests can be replicated at commercial scale, while providing data on leach kinetics, solution flow, and reagent consumption to refine heap pad design and operating costs.
Meanwhile, Norwest plans to extend metallurgical studies to fresh rock material once more of it is upgraded from inferred to indicated categories through ongoing infill drilling. This step is essential to assess the broader resource’s amenability to heap leaching and to support future development decisions.
Bottom Line?
Norwest’s robust metallurgical results and resource expansion set the stage for a pivotal scoping study, but confirmation from ongoing column leach tests will be crucial before production targets can be credibly defined.
Questions in the middle?
- Will column leach testing confirm the high recoveries seen in bottle roll tests at commercial scale?
- How will the scoping study balance near-term heap leach development with longer-term resource growth?
- What environmental challenges might emerge when updating historical approvals to current standards?