NR metallurgical testing study...good results...moving closer
posted on
Mar 28, 2011 01:37PM
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March 23, 2011
Stans Energy Corp (TSX-V: RUU) (‘Stans’ or ‘the Company’) has received its internal, 179-page, lab-scale report on Kutessay II metallurgical testing at the concentrate stage, completed by Information Research Center LLC (IRC), and reviewed by the Leading Russian Research Institute of Chemical Technology (VNIIHT). IRC’s main objectives were to improve upon the historical method of creating rare earth oxide (REO) concentrates from Kutessay II in four categories:
1. Decrease the costs associated with the historical milling process;
2. Recover additional polymetalic byproducts;
3. Increase the Total REO (TREO) content within the concentrate significantly above the historical 6.5% grade, and;
4. Increase the TREO recovery above the historical average of 64%.
Samples
Two representative samples of the Kutessay II resource were taken for testing, labeled TI and TII. TI was sampled from the underground adit No 28, consisting of 10 different areas of the resource in both the north and central zones. TI’s grade was 0.388% TREO. TII was sampled from stockpiled, crushed ore sitting in the bottom of the Kutessay II pit. TII’s grade was 0.565% TREO.
Concentration Model Tested vs. Concentration Model Proposed
Modern magnetic and gravitational milling techniques were analyzed and tested on both samples. Historical testing completed by Soviet Institutes in the 1980s lead IRC to believe that magnetic separation was the best option at the first stage of the milling process after grinding to a grain size of -0.5 mm. Results from magnetic tests on samples TI and TII concluded magnetic concentration on original ore to be inexpedient. Lab scale gravitational separation proved a superior first step, when compared to Magnetic separation, however, to properly test the new proposed gravitational concentration process, a pilot scale Falcon concentrator is needed. Based on these results, IRC, in association with VNIIHT, and under the supervision of Dr. Valery Kosynkin, have come up with a proposed concentration flow sheet to be tested at a pilot scale. An illustration of this process can be viewed on Stans’ webpage, www.stansenergy.com/rare-earth-processing/
The proposed concentration method addresses IRC’s objectives in the following ways:
1. Costs – The proposed process has been estimated to reduce the amount of processed material by up to 60% after the 1st stage, when compared to the historical method. Lab tests indicate this step has the potential to significantly reduce the historical costs of crushing the ore to a powder, floating, and drying.
2. Byproducts – Tests including magnetic separation were able to achieve recoveries in the concentrate of 80.0-80.5% Silver, 77.5-80.0% Lead, and 84-89% Bismuth. Recoveries of Zinc and Molybdenum ranged between 48.0% and 57.0%.
3. TREO Content – Testing of both samples achieved a TREO content in the concentrate ranging from 13.373% to 19.471%, a significant increase from the historical average of 6.5% TREO. To increase the quality of the final concentrate (removal of ore magnetite and technogenic iron appearing from ball grinding in the ball mill), IRC recommended to subject the final concentrate to magnetic separation. If the proposed milling process is implemented, and scaled results are similar or better than to lab tests, far less waste rock would have to be trucked to Stans’ newly purchased RE Processing Complex.
4. TREO Recovery – Achieved throughout recovery, with magnetic separation as step 1 and not accounting for additional recoveries from flotation of stage 2 and 3 gravitational tailings, ranged between 47.65% and 51.68% TREO. Gravitational separation tests without magnetic separation achieved recoveries for the individual REE in the range 0f 50 – 72%. The proposed 3-stage gravitational separation process will test RE tails after stage 2 and stage 3 for additional REO recoveries through control flotation, calcinations, and chemical dissolution in an attempt to increase recovery numbers.
Stans’ pilot scale study in 2011 will determine whether this proposed milling process, or the historical flotation process will be most cost effective.
The scientific and technical information in this document was reviewed, verified and compiled by Stans Energy Corp.’s geological and mining staff under the supervision of the company’s qualified person, Dr. Gennady Savchenko FGS, Managing Director, Stans Energy KG.