Pioneer Minerals (ASX:PMM) has identified an increase in tungsten grades by up to 17.6 times from preliminary metallurgical beneficiation testwork conducted at the historical Springfield Tungsten Mine within the North Pine Project in Idaho, US.
Testwork undertaken on composite materials collected from tailings returned grades up to 25,942 parts per million (ppm) of tungsten, equalling around 3.27% tungsten trioxide using gravity separation.
Using a heavy liquid separation process, material from the Springfield Mine returned 9,060ppm of tungsten, equalling 1.14% tungsten trioxide. Pioneer says the heavy liquid separation process confirms the material to occur in “high-density mineral phases amenable to gravity-based separation”.
Size-by-assay analysis peaked at 3,230ppm tungsten, equaling 0.407% tungsten trioxide, indicating tungsten enrichment from coarse to fine fractions.
Metallurgical testwork is ongoing for material sourced from the Springfield Mine. The program is being completed by Mineral Technologies.
The next phase of metallurgical work will focus on detailed mineralogical characterisation, as well as particle size, to uncover mineral associations and liberation characteristics for optimal processing strategies.
Pioneer will focus on clearing and reopening the access road to the mine to enable upcoming exploration and drilling, while also completing an electromagnetic geophysical survey.
CEO Michael Beven says the preliminary metallurgical testwork provides an “encouraging early indication of how tungsten contained within the historic Springfield tailings material responds to conventional beneficiation processes”.
“The size-by-assay results shows that tungsten becomes progressively enriched within the finer particle size fractions, which is consistent with the behaviour expected from fine-grained tungsten mineralisation,” Beven says.
“Importantly, the material being tested represents tailings generated during historical mining activities where processing was focused on recovering coarse tungsten minerals.
“As a result, the remaining tailings provide a useful proxy for understanding how finer fractions of tungsten mineralisation within the Springfield system may behave during processing.
“These insights will assist in guiding metallurgical evaluation of future exploration discoveries across the North Pine Project.”
Pioneer Minerals is a North American critical minerals explorer, advancing a portfolio of tungsten, antimony, uranium, and lithium projects.
Write to Maddison Elliott at Mining.com.au
Images: Pioneer Minerals
