Colombian Mines Mercedes Project Returns Highly Favorable Metallurgical Results

Colombian Mines Corporation (TSXV:CMJ)  is pleased to announce highly favorable metallurgical tests which yielded flotation concentrates containing 18.26 grams gold per tonne (g/T Au), 10,025 grams per tonne (g/T Ag) and 262.6 kilograms copper per metric tonne (kg/T Cu) with overall recoveries of 92% of the contained gold, greater than 79% of the silver and 35% of the copper for mineralization from the Company’s Mercedes project.
Test Results
The metallurgical tests were conducted by the highly respected firm of McClelland Laboratories Inc. of Reno, Nevada. The metallurgical sample was composited from the Company’s previous sampling at Mercedes and was designed to represent mid-range mineralization and excluded very high grade samples where grades to 50 g/T Au, 1,120 g/T Ag and 26% copper (Cu) in outcrop have previously been reported by the Company. The head grade of the composited sample was 0.5 g/T Au, 481 g/T Ag, and 2.85% Cu.
Metallurgical testing was conducted on material ground to 80% passing 75 microns (200 mesh), typical for modern flotation concentration plants. Concentrates produced contained just 3.67% by weight of the head feed weight with excellent concentration ratios of 48:1 for gold, 32:1 for silver and 15:1 for copper and overall recoveries of 92.0% of the contained gold, 79.2% of the contained silver and 35.5% of the contained copper.
This early stage testing clearly shows the mineralization at Mercedes is readily amenable to conventional flotation. Additional test work such as refinement of activating, conditioning and collector chemicals will likely increase recoveries of both copper and silver mineralization and may marginally increase gold recoveries from those achieved in this test. Additionally, surface weathering and oxidation are known to adversely affect flotation recovery of sulfides by coating the surface of sulfide grains with coatings of various oxide minerals that do not respond to flotation. Future test work on mineralization less effected by weathering and oxidation from drill holes and/or production are expected to be more amenable to flotation concentration and to yield higher recoveries.
Rational for Early Phase Test Work
Colombian Mines has a policy of conducting metallurgical test work early in the project exploration process to characterize mineralization and permit early identification of metallurgical issues and concerns which could result in adverse future economic impacts.
Conclusions
The results of this preliminary metallurgical test work are highly favorable, confirming the mineralization responds well to conventional froth flotation with excellent concentration ratios at grind sizes readily achievable in modern flotation plants with relatively simple and cost efficient “off the shelf” technology.
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