ASX-listed West African bauxite player, Lindian Resources has been buoyed by the successful results of screening test work done on high-grade sample ores from the Bouba conglomerate bauxite deposit at its Gaoual bauxite project in Guinea. The company says the simple dry screening process that was put through its paces resulted in a significant reduction in the levels of the silica impurity and an increase in the aluminium oxide grade in high-grade conglomerate ore samples that were tested, with minimal loss of tonnage.
The purpose of the recently completed test work program was to determine the potential for upgrading of the conglomerate bauxite ores comprising high-grade aluminium oxide and a high silica content, to ores consisting of higher-grade aluminium oxide and lower levels of silica through the removal of fine-grained material.
According to Lindian, the screening of the high-grade Bouba conglomerate resource sample ores – sourced from test open pits – culminated in the aluminium oxide grade rising from an average of 53.8 per cent to an impressive 58.4 per cent and the average silica grade reducing by more than 70 per cent, from a high 9.8 per cent to a low 2.8 per cent. The Perth-based company pointed out the test work also demonstrated a consistent upgrade in all high-grade conglomerate ore samples.
Gaoual’s Bouba conglomerate bauxite deposit hosts an indicated open-pittable resource containing a higher-grade portion totalling 83.8 million tonnes of ore grading an average 51.2 per cent aluminium oxide and 11 per cent silica. Lindian believes the simple screening process now has the capacity to significantly upgrade the ore quality.
Typically, the more silica in bauxite ores, the higher the amount of caustic soda required in the refining process and the higher the loss of aluminium oxide content. Lindian’s test work showed the coarse component of the conglomerate bauxite ores formed 87.2 per cent of the mass volume total in the high-grade sample ores tested, with the fines material component making up the balance.
Lindian Resources Chairman, Asimwe Kabunga said: “This is a very exciting discovery for Lindian. discovery for Lindian. The Bouba conglomerate ore when screened is now shown to be the highest quality bauxite in Guinea. It assists our broader vision and ambitions, which is to bring into production our large, multi-generational bauxite assets, but also strengthens Lindian’s ability to attract high calibre development partners.”
Senior Geologist Consulting to Lindian, Mark Gifford said: “The screening test work … has provided conclusive support to the assumption that by removing the fines material from the conglomerate ores the resultant bauxite would dramatically improve in quality.”
Lindian hopes to graduate from explorer to Guinean bauxite producer status in the short term via the low CAPEX development of the smaller Woula project while at the same time looking to advance the much larger Gaoual and Lelouma bauxite projects.
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By Matt Birney
