Mining royalty company Altus Strategies has announced “excellent” results from metallurgical testwork on oxide and sulphide samples from it 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.
The results show 98.3% recovery at moderate (75 μm) grind size on an oxide sample for a CIL scenario; 86.8% recovery at moderate (75 μm) grind size on sulphide samples for a CIL scenario; and 95.8% recovery at coarse (6.3 mm) crush size on an oxide sample for a heap leach scenario.
There is an expectation for a significant upgrade to the existing preliminary economic assessment (PEA).
Significant resource growth and discovery potential is considered to exist at Diba, says Altus.
"The results of the metallurgical testwork on both oxide and sulphide 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 (sulphide) samples shows that CIL processing will likely be very effective, with 86.8% gold recovery at attractive grind sizes,” comments Altus CE Steven Poulton.
"Diba already boasts a robust $81-million post-tax net present value for the oxide ounces alone. The significantly enhanced recoveries and addition of the sulphide 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,” he adds.
The company has engaged Mining Plus UK to update the existing Diba PEA to incorporate the higher oxide recoveries reported.
"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 multimillion-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,” Poulton notes.
Grinding Solutions of Truro has been commissioned by the company to investigate the heap leach and CIL amenability for the oxide and sulphide domains of the Diba gold deposit.