Southern and West Africa-focused multicommodities natural resource company Premier African Minerals in June commissioned a follow-up study to review low-capital options and near-term production alternatives for its Zimbabwe-based exploration project RHA tungsten and its Zulu pegmatite project.
This was after the company had announced a substantial increase in the indicated and inferred resource at the RHA tungsten project, in which Premier is the operator and holds a 49% interest.
Premier states that its original mine study, which was completed in February, suggested an initial openpit approach, which would later develop into a decline for future underground mining. The alternative approach, currently under review, contemplates an immediate start to mining operations through the use of the existing underground development and shaft system, and the construction of the tungsten plant at the historic site.
According to Premier, the plant and flow sheet are expected to be similar in design and capacity to the plant and flow sheet contemplated in the initial mine study. The company states that, with the adaptation of the alternative mining approach, production could start in 2015 at a reduced mining rate, with expansion taking place progressively thereafter. The alternatives under review expect that Premier would finance this without the need to raise further equity.
“Initial mineralogical and metallurgical studies on which the RHA mining study update is being based have been completed. The mineralogical study has indicated high-grade concentration and expected recoveries of the order of 88%,” says Premier.
The metallurgical study sample grade was assessed using a composite of all boreholes, including those parts of the orebody that will not be mined. It found that, while the recovery of about 60% is acceptable, the outcome is estimated.
“This is why additional metallurgical testwork is now being undertaken, using new underground material samples, to enable optimisation of the tungsten crushing and milling processes,” says the company.
The new mining study will reassess the project potential in light of additional information that will become available, including updated geological and mineral resources and indicated and inferred categories.
Premier CEO George Roach says the company sees this follow-up study as a necessity that it cannot overlook. “Following completion of our two transactions, the Circum and AgriMinco transactions, Premier now has the funding to contemplate the low-capex, near-term production alternatives for RHA.
“While I am frustrated that the metallurgical studies need to be repeated, a satisfactory result will significantly strengthen our confidence in the project,” says Roach.