Mineral exploration company Mount Burgess Mining MD Nigel Forrester says ongoing metallurgical and mineralogical testwork, conducted at the company’s Kihabe–Nxuu zinc/lead/silver/gallium/germanium/vanadium mine project, in western Ngamiland, Botswana, indicates the feasibility of metals production on site and local beneficiation.
“We’re focusing on the fact that the top portion of the Kihabe deposit, and the whole of the Nxuu deposit, is oxidised. This means that we will be able to produce metals on site with anything that we extract from these oxidised zones.”
This will negate the need to export concentrates to smelters in countries such as China.
Forrester adds that, to fully capitalise on this opportunity for local beneficiation to the benefit of Mount Burgess Mining and Botswana, the company is consulting with various stakeholders on how to implement local beneficiation and use these minerals for end-products.
An important consideration would be on whether vanadium redox flow batteries (VRFBs) can be manufactured locally, he notes.
“What’s being shown from our latest drilling results is that we have a polymetallic deposit. We are dealing with six different metals – zinc, lead, silver, vanadium pentoxide, gallium and germanium.”
Forrester emphasises that vanadium is hosted within a mineral called descloizite, which is an oxide mineral.
“In descloizite, vanadium pentoxide is 1.79 times the volume of vanadium. We also know from the testwork completed to date that we can recover about 81% of our vanadium pentoxide on site.”
He explains that, to recover vanadium pentoxide on site and beneficiate it, Mount Burgess Mining will initially use a gravity separation process.
Thereafter, remaining material would be subject to flotation, using a hydroximate acid reagent for recovery to a concentrate.
Subject to the progression of the project and negotiations with key stakeholders, Forrester notes that a portion of the extracted minerals will be set aside for local consumption in Botswana, while the rest will be exported.
Critical Metals Market
Forrester emphasises the possible importance of vanadium pentoxide, gallium and germanium for the global critical metals market.
“We see vanadium pentoxide as a metal that’s going to be necessary for the future, as it can store huge amounts of power over long periods. It can also withstand variations in storage levels over short periods without deterioration to the battery. This is beneficial – usually, unless you keep the storage level constant, you get high battery deterioration.”
He highlights that vanadium can be used in the manufacturing of VRFBs.
Further, gallium and germanium are emerging as critical metals, owing to their being used in fifth-generation cellular network technologies.
Fifth-generation networks have a high volume of international data transmission, which older silicon data chips are not equipped to deal with, unlike newer chips that use gallium.
Forrester adds that regions such as the US and Canada have also placed gallium at the top of the critical supply list, as these countries have been relying on gallium imports from China. Both countries, but particularly the US, are conducting research to enable them to generate their own supply of critical metals.
Germanium, meanwhile, is used for technologies such as fibre optics, infrared optics and similar technologies.
“The world is changing because of the decarbonisation trend, and that means we’re going to need a lot more of these metals to cope with that necessary change,” Forrester concludes.