Press release: Promising test concentration of the Fäbodtjärn quartz vein at LTU

Botnia Exploration’s board of directors decided in spring to investigate the characteristics of the Fäbodtjärn gold mineralisation with only gravimetric concentration and without any chemical additives. Due to the proven high gold contents of Fäbodtjärn, it is probable that concentration will be possible to perform with only gravimetric methods. Such a process would considerably reduce the cost per tonne, but also future investments in a concentration plant.

Botnia Exploration therefore gave MiMeR, the Division of minerals and metallurgical engineering at LTU, the assignment to conduct exploratory tests in order to process the gold mineralisation in a quartz boulder by wet gravity separation. Tests have been conducted with separation in a so called Knelson separator to establish possible yields and with shaking table to investigate what contents are possible to reach. Both methods are “gravimetric” and use the characteristics of the gold, with its density that is so much higher than the surrounding rock.
A test sample of approx. 53 kg has been concentrated at MiMeR. It was first crushed extra fine, to less than 1 mm. The result shows that by only extreme fine crushing in combination with simple wet gravity concentration, it is possible to reach 60% yield of gold in a concentrate with more than 100 g/tonne Au.
The tests confirm that the gold content in the quartz boulder in average is approx. 14 g/tonne. The waste content in the conducted tests was 6.2 g/ton Au. This is high and continued tests with grinding of the material followed by new concentration will increase the yield.
A Knelson separator is a batch-operating bowl centrifuge, which is used to capture small amounts of heavy and fine material, for example gold. Usually the concentrate is processed on a shaking table to increase the content. The shaking table is a reciprocating table, which by a water film separates heavy and light minerals.
“The results are very gratifying and can directly be compared to the results reported in GeoVista’s report and press release on June 18. The test mining of Fäbodtjärn is planned to be performed by a basic pipe trench and a tonnage of approx. 8000 tonnes. We have calculated with a gold content of 5 g/t or a production of approx. 40 kg gold. With the results shown at LTU, we can look forward to an interesting test mining, hopefully in summer 2015 provided all permits are approved by the County Administrative Board and other stakeholders”, says Bengt Ljung, CEO for Botnia Exploration.
“I think that the relatively high waste justifies further investigations, where the ore is first coarsely grinded and then processed in a Knelson separator and shaking table again. Still no chemicals will be needed in the concentration”, says Docent Bertil Pålsson at MiMeR.
For further information, please contact:
Bengt Ljung, CEO – Botnia Exploration
Phone: +46 705 431605
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