Following positive X-ray Transmission (XRT) ore sorting test work on the Pegmont asset, in Queensland, Australia, Vendetta Mining is looking to apply this technology in its next mining study at the lead-zinc project.
The test work, conducted at TOMRA’s testing facility in Sydney, Australia, concluded that the XRT sorters could distinguish between high-density/high-grade feed and lower-density waste material at Pegmont, the company said.
Vendetta said: “At Pegmont, the potential advantages of XRT material sorters is that they could allow plant feed material to be screened prior to grinding and flotation, removing lower density external dilution (waste) and lower-grade internal dilution (material below cutoff).”
Potential capital cost savings occur through the reduced mill throughput while potential operating costs savings occur through reduced water and reagent usage, less pumped tails and lower energy requirements, it said.
The test work envisages that sorted waste product would be ejected and stacked for dry disposal (dry stack tailings).
Vendetta said: “Flotation recovery often improves with increasing head grade. Such a relationship exists in the metallurgical test work performed at Pegmont to date. The higher head grades obtained from the ore sorted product are anticipated to result in enhanced flotation recovery.”
The testing involved material from two drill hole intersections from Zone 5 and one from Zone 2 at Pegmont. The sulphide intersections were selected in order to test different lead to zinc ratios (Zone 5 vs Zone 2) and internal grade distributions, it said. All samples included diluting quartzite material from the hangingwall and footwall.
The conclusions of the XRT ore sorting preliminary test work on the three drill intervals are it can successfully remove the external dilution from the samples; and successfully remove internal diluting material from within the higher-grade intervals.
The total mass tested amounted to 139.2 kg, with the mass pull (weight % of feed recovered) ranging from 44.3% to 70.6% (a weighted average of 62.3%).
The lead grade improved from 18% to 88%, a weighted average of 42%; zinc grade improved from 21% to 72%, a weighted average of 38%; lead recoveries ranged from 83.2% to 90.2%, a weighted average of 88.5%; and zinc recoveries ranged from 76.4% to 92.2%, a weighted average of 85.9%.
Vendetta said that while these results were highly encouraging, they are preliminary. “In order to apply material sorting results in an updated preliminary economic assessment (PEA) study, pilot scale test work is necessary,” the company said.
TOMRA recommends 600 kg of material is required for each ore type at Pegmont. Vendetta plans to pursue this test work and expects these samples will be obtained from the next drilling program. Samples will be obtained from Zone 1 transition, Zone 2-3 sulphide and Zone 5 sulphide.
Michael Williams, President and CEO, said: “At Pegmont, the XRT sorter can clearly differentiate between high density/high grade feed from lower density waste material at Pegmont. We are excited by the prospects of advancing to pilot scale test work and applying this commercially available technology to the next mining study.”
The existing Pegmont PEA contemplated a production rate of 1.1 Mt/y, which corresponds to two TOMRA COM XTR 1200 – generation one ore sorters, Vendetta noted.