During the year, Triton received metallurgical test work results that have confirmed that the Nicanda Hill graphite ore, through standard flotation methods, is readily able to produce graphite concentrates which assay from 95.8%TGC to 97.3%TGC.
Triton has also begun a metallurgical program, being undertaken by Mintek (Johannesburg), which will be incorporated into the forthcoming feasibility program. This new program will include variability metallurgical testing to identify and confirm larger areas of near-surface large flake graphite material and to verify the methodology for the optimisation in the recovery of the various graphite flake sizes.
The metallurgical results received during the year confirmed that the graphitic concentrate produced through the standard flotation methods contain low levels of impurities, which confirms that the graphite is liberating cleanly from the graphitic ore.
The tests verified low levels of volatiles and impurities. These flotation tests produced graphite concentrates with a weighted average purity of 97.1%TGC, 2.7% Ash and 0.2% Volatiles, without the need for chemical treatment.
Metallurgical tests have further confirmed that Triton is able to upgrade the Nicanda Hill graphite concentrate up to 99.9%C using simple chemical wash.
To upgrade graphite flotation concentrate, samples were digested in 20% solution of hydrochloric acid (HCl) at 20% solids (w/w) for 4 hours at 80ºC in a water bath to remove carbonate and iron oxides.
The residue was then thoroughly washed to remove all acid and leached in 8% solution of hydrofluoric acid (HF) at 20% solids (w/w) for 4 hours at 90ºC to remove silicates. The final residue was thoroughly washed, dried and assayed for graphitic carbon.
Leaching is a very effective method to remove gangue minerals from graphite concentrate without flake size reduction. The amount of consumables required for the purification process is very low due to the very high grade of the graphite concentrate and the low levels of the impurities which can be readily removed.
In addition to the above, the metallurgical test work undertaken to date shows that both vanadium and zinc are present in the process tailings after the flotation and separation of the graphite concentrate from the ore. Also of note is the presence of other base metals, including titanium, in the tailings.
In the initial testing, vanadium was readily upgraded through a standard flotation of graphite tailings to produce vanadium concentrate with grades up to 0.74% V2O5.
A zinc concentrate assaying 7% was also produced from the graphite tail through simple flotation process.
Further metallurgical investigations are required in order to optimise flotation conditions and improve both vanadium and zinc recoveries so that they may be further upgraded. Accordingly, the vanadium and zinc potential of the Nicanda Hill resource is still to be fully understood.
Should the vanadium and zinc be found to be upgradable from the tailings as a saleable concentrate, this would have a major positive impact on the overall economics and profitability of a potential mine at Nicanda Hill.