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Thursday, 8 November 2012
Tasman Metals advances mineral processing at Norra Karr, enabling high recovery-low mass mineral concentrate
Tasman Metals (CVE:TSM) (NYSE-MKT:TAS) says it has advanced mineral processing at its Norra Karr heavy rare earth element (REE)-zirconium project in Sweden, based on recent optimization results from expanded metallurgical testing.
Test work was completed in Germany by ANZAPLAN, a member of the DORFNER group of companies, a big German supplier of industrial minerals.
The company said highlights included high recovery of rare earth elements in a low mass during combined flotation and magnetic separation tests, including 82.5% yttrium oxide (Y2O3) and 76.9% total rare earth oxide (TREO), recovered in only 25.2% of the original mass.
Various scenarios combining flotation and magnetic separation were tested.
It also saw a high recovery of rare earth elements in magnetic separation tests on three major ore types from the project.
Eudialyte was confirmed as the only rare earth element-bearing mineral present in "more than trace abundance" in all ore types.
"While most REE projects display a complex range of REE-bearing minerals, REE's at Norra Karr are virtually entirely hosted by eudialyte, minimizing complexity in the processing flow sheet," said the company in a statement.
In addition, all major ore types were shown to be mineralogically indistinguishable when ground to 500 micron, suggesting geological variation across the ore body is unlikely to affect processing behaviour, Tasman added.
Flotation test work was also "very successful", the company noted, in separating the common iron-bearing aegirine from eudialyte using commerical reagent.
Low-iron nepheline/feldspar fraction was identified as potential by-product, Tasman said.
Tasman is now focused on further improving the eudialyte concentrate quality by multiple stage magnetic separation and re-grinding methods that were successfully tested by the Geological Survey of Finland in earlier bench scale tests.
"The effectiveness of the current optimization tests for combined magnetic and flotation techniques by ANZAPLAN give us confidence that further research will enable a high recovery - low mass mineral concentrate to be produced from Norra Karr ore," said president and CEO, Mark Saxon.
"Our metallurgical research is a continuous process, with facilities in Europe and North America working to further optimize the flow sheet. Data generated by ANZAPLAN will be a key part of our upcoming Pre Feasibility Study and Pilot Plant tests."
For the tests, three bulk samples totaling around 1.2 tonnes were supplied to the company's consultants, representing the two major and one minor ore type that comprise the Norra Karr resource.
Each sample was composited from drill core collected across the deposit. All previous metallurgical testing was performed on blended material combining all ore types.
The company said the relationship between flotation and magnetic separation, and the impact on operating and capital costs is now the subject of ongoing research.
A concentrate sample produced by flotation and magnetic separation has been supplied to a research partner for additional hydrometallurgical leach testing, the miner added.
The project’s preliminary economic report was based on an open pittable recoverable resource of 58.1 million tonnes grading 0.59 per cent total rare earth oxide (TREO) where 50.0 per cent of the TREO is the high value heavy rare earth oxide (HREO) and 1.70 per cent zirconium oxide in the inferred and indicated categories.
The report assumed a mining rate of 1.5 million tonnes per year with average TREO recoveries of 80 per cent and average zirconium recovery of 60 per cent.
Average annual mixed TREO concentrate production was forecast to be 6,800 tonnes including 290 tonnes of dysprosium oxide, 43 tonnes of terbium oxide, 773 tonnes of neodymium oxide and 2,360 tonnes of yttrium oxide.
The project is one of the largest and most economical projects among its peers, due to the high contribution of the high value rare earth elements like dysprosium, yttrium, neodymium, and terbium.
Demand for dysprosium is expected to soar over the next decade from both the traditional automotive and emerging electric car and wind turbine industries. Supply of the metal, which is a key contributor to high temperature magnets, has become tight over the past year, with prices increasing more than 600 per cent since January 2011.
Last month, the company reported that its spring/summer drilling program at its Norra Karr project resulted in “exciting new discoveries”. The junior rare earths explorer said that the program included 70 new holes and two existing holes that were extended, for a total of 12,453 metres of drilling.
With the program resulting in a “substantial increase” of drilling data, the company said its upcoming pre-feasibility study will include an updated NI 43-101 resource calculation.
Tasman Metals also has the Olserum project, which it acquired last October and is located 100 kilometres east of Norra Karr.