Friday, February 8th, 2008
Global Minerals is pleased to announce that it has received the preliminary Metallurgical Report for its Strieborna silver/copper/antimony project, by Dr. Corby Anderson, Director and Principal Process Engineer of The Center for Advanced Mineral & Metallurgical Processing, Montana Tech, University of Montana. Dr. Anderson was the mineral processing engineer of Sunshine Mining and Refining Co., which carried out extensive metallurgical tests on concentrates from Strieborna in the mid-1990s.
The report outlines the design for a 500 Tonne Per Day Flotation Mill which, based on previous metallurgical tests, and on historical resource estimates, could produce approximately 40-50 tonnes of concentrate per day, grading 25-30 % Cu, 4000-5000 g/T Ag, 5-10 g/T Au 15-20% Sb, 0.75-1.0 % Hg. Based on historic information, the report assumes that ore grading approximately 489.3 g/T Ag, 2.093 % Cu, 1.376 % Sb, and 0.0439 % Hg would be mined at a rate of 500 tonnes per day for a total of 175,000 tonnes per annum, with the – proposed processing plant providing a recovery rate of between 90-95% from Ag and Cu bearing tetrahedrite.
The report further recommends that the flotation concentrate be treated for selective removal of antimony, arsenic and mercury using an alkaline sulphide hydrometallurgical process, which has been in use for over fifty years. Antimony metal or value added antimony products could also be produced, with arsenic being precipitated and stabilized as scorodite or ferrihydrite. Mercury will also be precipitated and stabilized as a polymeric solid.
Any gold in the concentrate could also be recovered utilizing this process, thus avoiding the use of cyanide. Additionally, value added by-products such as sodium sulfate, caustic, sulfuric acid or ammonium sulfate fertilizer may also be produced from this process as desired.
President and CEO George Heard commented, “We are delighted to have confirmed what management has believed all along – that a proven metallurgical process in use for over 50 years can recover the silver, copper and antimony from Strieborna ores – while at the same time stabilizing any potentially harmful substances.”