|January 11, 2017|
Rosita Mining Santa Rita Project - Updated Metallurgical Results
|Rosita Mining Corporation (RST:TSX-V) ("Rosita" or the "Company") is pleased to announce further positive metallurgical tests for the Company's Santa Rita Project presently underway at SGS Lakefield in collaboration with D.E.N.M. Engineering Ltd. |
In previously reported test results announced on September 21st, 2016, it was concluded that recoveries of gold by cyanide leaching from ground material was more than 90% from the stockpiles and 80% from tailings. 75% gold was recovered from coarser material. Copper recovery from cyanide leaching into solution was 35%.
The next stage of testwork reported here, was designed to test the recovery of copper and the recovery of cyanide from these leach solutions via the SART (Sulphidization, Acidification, Recycling, and Thickening) process
This SART testwork, has been very successful and is appropriate metallurgically for the Project :
The high cyanide consumption of 8.82 kg/T and 4.46 kg/T reported in the previous press release was due to the requirement to maximize the copper soluble dissolution and improve the kinetics of the gold leaching. In both cases, 60 % of the cyanide consumption was due to the copper complexing with the cyanide which is expected to be recoverable, along with the copper using SART technology. High recoveries of gold and copper were demonstrated.
Updated Test Work
The SGS testwork protocol described below is standard; it mimics the conceptual flow sheet that was devised from the initial SART testwork done for this project at SGS. (see figures 1 and 2) It involves standard process equipment using the standard gold and copper processing reagents.
The solutions from the leach tests were used for SART testing for recovery of cyanide from the copper complex, precipitation of copper and recycle of solution into ongoing cyanidation leach testing. A series of four (4) SART tests were carried out to test Acid addition pH rates, Sodium hydrosulphide (NaHS) stochiometric addition rates, recycle leaching to feed material, and also subsequent carbon loading rates.
The resultant optimized SART work is as follows (pH 4 and 100 % NaHS stochiometric addition rate) :
In general, the testwork has demonstrated that the SART process is appropriate for this project metallurgically for the Santa Rita material with solutions containing recoverable gold and copper.
Next Phase Testwork
The final ground tailings from the stockpile and tailings stockpiles leached material will be comingled with the screen +1/4-in. feed material to undergo column heap leach simulation. The work will commence shortly with completion in Q1 - 2017. The gold and copper recovery for this process is essentially known.
The test campaign underway at SGS Lakefield will be complete in Q1-2017 and the final SGS report will follow and used as the metallurgical basis for more detailed engineering.
The current testwork and engineering information together with local costs for labour, power, reagents, and rock moving have allowed the work plan for the environmental permit to begin..
This will join baseline work that has been ongoing at site for the past three months.
About Rosita Mining Corporation
Rosita is a junior mining and exploration resource company focused on growing shareholder value through the development of near-term mining projects and advancing accretive exploration opportunities.
Rosita and Calibre hold 65 % and 35 % interest respectively in the Rosita copper-gold-silver supergene/skarn/porphyry project in Nicaragua located 275 kilometres northeast of Managua.
David Salari, P.Eng. and John Cook, MIMMM, Qualified Persons, as defined by NI-43-101, have read and approved the contents of this press release.
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