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Altus Strategies announce metallurgical testwork results

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Global Mining Review,

Altus Strategies has announced results from metallurgical testwork on oxide and sulfide samples from the company's 100 % owned Diba gold project in western Mali. The work was undertaken to test the amenability of Diba ores to carbon-in-leach (CIL) and heap leach processing.


  • Excellent gold recoveries from oxide and sulfide samples from Diba gold project in Mali:
    • 98.3% recovery at moderate (75 μm) grind size on oxide sample for CIL scenario.
    • 86.8% recovery at moderate (75 μm) grind size of sulfide samples for CIL scenario.
    • 95.8% recovery at coarse (6.3 mm) crush size on oxide sample for heap leach scenario.
  • Expectation for a significant upgrade to existing preliminary economic assessment (PEA).
  • Existing PEA which applied a gold price of US$1500/oz and a 10 % discount rate:
    • Generated a robust US$81 million (post-tax) net present value (NPV).
    • Modelled 80% gold recovery for oxide heap leaching, compared to 95.8% reported.
    • Did not envisage a CIL processing route, thereby excluded all sulfide ounces.
  • Significant resource growth and discovery potential considered to exist at Diba:
    • Current mineral resource estimate (MRE) remains open along strike and down dip.
    • Seven further prospects within 7 km of MRE have yet to be systematically drill tested.
    • A resource expansion and target definition drill programme is now being planned.

Steven Poulton, Chief Executive of Altus, commented: "The results of the metallurgical testwork on both oxide and sulfide material from Diba are simply excellent. Heap leach amenability shows 95.8% gold recovery at a coarse crush size. This recovery is significantly higher than the 80% modelled in the current PEA which we reported on in July. More significantly, the testwork on fresh (sulfide) samples shows that CIL processing will likely be very effective, with 86.8% gold recovery at attractive grind sizes.

"Diba already boasts a robust US$81 million post-tax NPV for the oxide ounces alone. The significantly enhanced recoveries and addition of the sulfide resource should add considerable economic value to the project. We have commissioned an updated independent PEA and look forward to reporting on the results in due course.

"Aside from the existing resource area, Altus has defined seven priority prospects at Diba, none of which have ever been systematically drill tested. These prospects are all located within 7 km of the current mineral resource, which itself is only 13 km from the multi-million ounce Sadiola gold mine. Altus is currently planning a drill programme for Diba and we look forward to providing an update on this in due course."

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