Viking Mines reports assay results confirming TOMRA X-ray ore sorting can upgrade tungsten grades by up to 4.1 times and recoveries nearing 93% at its Nevada Linka Project.
- Ore sorting upgrades tungsten grade up to 4.1x feed
- Tungsten recoveries reach 93% in Conquest Pit sample
- Low-grade waste rejected at ~0.2% WO3
- Potential to upgrade existing surface stockpiles
- Gravity and flotation tests underway for downstream processing
Ore Sorting Demonstrates High-Grade Concentrates
Viking Mines Limited (ASX:VKA) has confirmed that TOMRA’s X-ray Transmission (XRT) ore sorting technology can significantly upgrade tungsten concentrate grades at its Linka Tungsten Project in Nevada. Assay results show high-grade products achieving up to 4.1 times the feed grade, with tungsten recoveries up to 93% in the Conquest Pit sample. The technology also effectively rejects low-grade waste streams grading around 0.2% WO3, promising a cleaner feed for downstream processing.
Grade and Recovery Highlights from Two Samples
Two grab samples from distinct sources; the Conquest Pit and Linka Stockpile; were processed through a three-stage cascade sorting configuration, producing four output streams each. The Conquest Pit high-grade fraction graded 1.91% WO3, roughly three times the calculated feed grade of 0.61% WO3, and contained 27.3% of the tungsten in just 8.8% of the mass. Combining sorted products with unsorted fines produced feed grades from 1.2 to 1.7 times the original, with recoveries between 62% and 93%.
The Linka Stockpile sample yielded a high-grade product at 1.83% WO3, over four times the feed grade of 0.45% WO3. Recovery rates ranged from 40% to 86% depending on product combinations. Notably, the low-grade reject streams in both samples consistently graded around 0.2% WO3, underscoring ore sorting’s ability to screen out waste or low-grade material ahead of milling.
Strategic Implications for Project Development
Managing Director Julian Woodcock emphasised the flexibility ore sorting offers, allowing Viking to prioritise either grade uplift or tungsten recovery in processing. The results support two key value propositions: pre-concentration of run-of-mine feed to improve plant feed grade and the upgrading of existing surface stockpiles to viable plant feed. This aligns with the company’s broader metallurgical program and will feed into the conceptual flowsheet Mineral Technologies is developing for a 300,000 tonne-per-annum processing plant.
Next Steps Focus on Downstream Processing and CAPEX Planning
Viking is advancing gravity and flotation testwork on the ore sorting products at Base Met Labs to evaluate downstream circuit performance. Concurrently, the company is assessing ore sorting’s potential to upgrade surface stockpiles and reviewing the processing flowsheet to incorporate ore sorting. A TOMRA equipment quotation will support the capital expenditure model under development, a critical step for project economics.
While the assay results come from grab samples of loose surface material; which may not fully represent in-situ ore variability; the data provide a promising indication of ore sorting’s role in enhancing the Linka Project’s feed quality and operational efficiency. The integration of these results with ongoing drilling and metallurgical studies will be pivotal for the project’s next phase.
Bottom Line?
Ore sorting at Linka could reshape feed quality and processing economics, but downstream performance and full-scale integration remain to be proven.
Questions in the middle?
- How will gravity and flotation results influence ore sorting’s role in the processing flowsheet?
- Can ore sorting consistently upgrade feed grades across broader ore types and stockpiles?
- What impact will ore sorting integration have on the project’s capital and operating costs?