OD6 Metals (ASX:OD6) reports ‘highly encouraging’ ore-sorting results showing clear discrimination between ‘high-grade’ fluorspar and lower-grade mixed and waste material at its Quinn Fluorspar Project in Nevada, US.
The company delivered 166kg of metallurgical samples across 11 discrete mining domains to TOMRA‘s test centre in Germany and Core Resources in Brisbane.
Head assays confirmed ‘exceptional’ grades across all four principal mineralised domains, with the Big Jim main vein returning 98.3% calcium fluoride (CaF2), Horseshoe mineralisation achieving 90% CaF2, the Blue Bell main vein recording 86.7% CaF2, and Horseshoe breccia delivering 76.2% CaF2.
The fluorspar content was also corroborated by independent quantitative X-ray diffraction (QXRD) mineralogy, which yielded 98.6% fluorite from Big Jim, 90.4% from Horseshoe, 91.6% from Blue Bell, and 48.5% from Mammoth.
Notably, QXRD identified fluorite as the only fluorine-bearing material, supporting interpretation of the fluorine assays.
TOMRA’s laser and X-ray transmission technologies also demonstrated the ability to separate ore from waste at coarse particle sizes prior to milling and flotation across the Blue Bell, Big Jim, and Horseshoe domains.
OD6 highlights Big Jim as “particularly exceptional”, as results for this main vein sample exceed the typical CaF2 requirement for acidspar. That said, the company says further testing is required to determine whether a directly saleable product can be produced.
More than the grades, Managing Director Brett Hazelden says the results show how different mineralisation styles at Quinn could be mined and processed.
“We deliberately did not just send TOMRA and Core our best-looking fluorspar. We selected discrete samples representing high- and medium-grade mineralisation together with hanging-wall, footwall, and internal waste so that we could understand how mining dilution may behave and, importantly, whether it can be removed before milling,” Hazelden says.
“At Blue Bell, Big Jim, and Horseshoe, TOMRA has demonstrated very clear discrimination between these material types.
“This potentially gives us the ability to reject waste at a coarse crush size, upgrade selected material towards a metspar [metallurgical-grade fluorspar] product, and substantially reduce the tonnes that ultimately need to be ground and floated to produce higher value acidspar.”
According to OD6, early waste rejection offers potential to lower capex and opex by reducing grinding power, water, reagent consumption, and tailings generation — all while increasing calcium fluoride feed grade.
High natural grades also support a direct shipping metspar product option to generate near-term cash flow ahead of a full flotation circuit.
OD6 adds that upgraded feed can also be directed to flotation to produce higher value acidspar.
Following these results, the company intends to progress larger scale ore-sorting trials using 500–1,000kg bulk samples to establish quantitative mass rejection and grade uplift, while continuing metallurgical test work with Core Resources.
Fluorspar is classified as a critical mineral in the US, which currently imports 100% of its supply.
OD6 Metals is a critical minerals explorer and developer with projects spanning fluorspar, rare earth elements, and copper across the US and Australia.
Write to Paula Fabe at Mining.com.au
Images: OD6 Metals
