A scoping study has confirmed that ASX-listed Sovereign Metals’ Duwi flake graph- ite deposit, in Malawi’s central region, is the world’s sixth-largest deposit of the mineral.
Graphite is used in refractory applications and as a conductor of heat and electricity, as well as in lubrication and increasingly in advanced energy-storage applications.
Sovereign Metals director Matthew Syme says the study revealed that the Duwi Main and Duwi Bend deposits host 77.3-million tons of indicated and inferred resources at 7.2% total graphitic carbon (TGC) for 5.57-million tons of contained graphite at a 5% TGC cutoff.
He explains that, based on the study, Sovereign Metals is considering two production scenarios, namely processing 30-million tons of Duwi Main and Duwi Bend ore at the rate of 1.5-million a year to produce 110 000 t/y of flake graphite concentrate over 20 years, or processing 11-million tons of Duwi Main ore at the rate of 0.55-million tons a year to produce about 40 000 t/y over 20 years.
Syme explains that, should the project go ahead, an openpit will be established at Duwi Main, with a shallow satellite pit at Duwi Bend.
He says contract mining has been selected to mitigate project risk, although operational management will be retained by Sovereign personnel.
Syme reports that Sovereign has undertaken a range of characterisation and mineralogical examinations and testwork programmes on fresh ore and surface saprolite material from the Duwi deposit.
He explains that the key component of the work has been the flotation programmes designed to optimise graphite recovery, while also maximising flake size and integrity.
“Work to date has prioritised the development of an optimal flotation flowsheet, which has been used as the basis for the scoping study. The process flowsheet objective is to maximise recovery of jumbo (+300 µm) flakes and minimise the production of amorphous powder (–75 µm). Further testwork is currently in progress to optimise other areas of the flowsheet, and early results show that concentrate size fractions can be upgraded to greater than 95% TGC,” he says.
Syme states that ore processing will take place in a dedicated, purpose-built processing plant located close to the deposit and that the flake graphite product will be packed and containerised on site before being shipped to end-users.