Forte Energy NL (ASX, AIM: FTE) has reported encouraging preliminary results from metallurgical investigations on samples taken from its wholly-owned Firawa uranium project in Guinea, West Africa. Forte said that the initial results, which indicate uranium recovery rates of 67% from 8-hour acid leach testing, confirm the potential for a heap-leach operation at Firawa.
The company plans for further pre-feasibility optimisation testing to be undertaken, aimed at reducing acid consumption and further improving uranium recovery rates. Also, Forte told investors that it is currently planning a drilling program on the remaining 50% undrilled anomaly.
The drilling will commence at the end of Q3, after the wet season, in order to extend the current JORC resource. Back in July 2009, Forte Energy reported an initial JORC-compliant Inferred uranium resource of 17.7Mt grading 296ppm (parts per million) triuranium octoxide for 11.6 million pounds of contained U3O8. The company said there is potential for the resource to be increased as the deposit remains open along strike and down dip.
Forte hired Perth-based Mineral Engineering Technical Services Pty Ltd (METS) to undertake the metallurgical testing to assess the deposit for potential heap leach recovery.
METS initially conducted a Preliminary QEMSCAN (Quantitative Evaluation of Minerals by Scanning Electron Microscope) analysis of composite samples from Firawa to assess the mineralogy. “This analysis showed that 99.99% of the contained uranium is hosted in the mineral crandallite, a calcium aluminium phosphate which made up 27% of the composite samples tested. Goethite (41%) and hematite (15%) were the other major components identified”.
The QEMSCAN analysis also suggested that reducing the iron content with gravity separation before leaching will also be a likely avenue for improving leach recoveries.
Following the encouraging mineralogical analysis and some initial leach testing on raw samples, Forte Energy also forwarded additional Firawa samples to METS, to carry out further leach testing as a precursor to feasibility studies.
According to Forte, this testing is investigating the effects of acid concentration, temperature and grind size and potential for upgrading the ore with gravity separation, to optimise the uranium extraction from the crandallite.
The preliminary test plan examined samples crushed to 1mm then undergoing gravity separation via tabling. Resulting samples were then split and underwent both pug roast leach testing and direct acid leach testing with sulphuric acid.
The company noted that the pug roast leach testing resulted in the recovery of around 55% of the uranium and 49% of the iron content. The maximum uranium extraction, from the direct acid leach tests, was 67.2% after 8 hours of leaching. Forte highlighted that "this represents a considerable improvement from the 35% recovery achieved from the initial leach test on raw samples".
“Further investigation aims to optimise the leaching to improve uranium recovery and reduce acid consumption”, Forte stated.