Mosquito Receives Excellent Preliminary Metallurgy Report on CUMO
VANCOUVER, BRITISH COLUMBIA–(Marketwire – June 17, 2008) – Mosquito Consolidated Gold Mines Limited (Mosquito) (TSX VENTURE:MSQ) is pleased to report that it has received an excellent preliminary metallurgy report on its Idaho-based CUMO molybdenum project from SGS Vancouver Metallurgy (SGS) entitled “The recovery of molybdenum, copper and silver from the CUMO Samples”. The report covers 75% of the metallurgical work to be completed.
In December 2007, 114 drill core samples from CUMO drill holes 27, 28 and 29, totaling 745.5 kilograms and sorted into the three mineralized zones, Cu-Ag, Cu-Mo and Mo, were delivered to SGS for analysis. To date, rougher and cleaner flotation, QEMSCAN mineralogical, and bench scale grinding studies have been completed on the three zones.
Overall, the results of the studies completed show better-than- expected recoveries in all parts of the deposit and confirm that even at the low-grade end the recoveries are excellent. Two different grinds were used, with the finer grind giving better recoveries, especially in the case of copper. The material is straightforward, with relatively low concentrations of problematic minerals such as pyrite, clays and talc, lending itself to effective Cu/Mo separation to create two saleable concentrates. Reagent consumption appears to be slightly below average, due to the lack of problematic minerals, indicating that processing will be low-cost and relatively straightforward.
To date, Mosquito’s own internal economic analyses of the deposit have used the following recovery rates: 90% Mo, 60% Cu, and 50% Ag. The metallurgical study results indicate that much higher recoveries can be achieved for all three metals, even at the lowest grades. For example, in the cleaner flotation study, recoveries for molybdenum were 97.5% in the Cu-Ag zone, 93.7% in the Cu-Mo zone, and 94.9% in the Mo zone. Detailed results of the rougher and cleaner flotation studies are provided below.
Geologically, the excellent recoveries are to be expected. For example, in the cleaner concentrate for the Mo zone, the assay grade for copper is only 0.03% Cu, yet recoveries were 91.1%. This is the result of the copper being contained not in the host rock, but in the quartz vein stockwork, which in itself accounts for only one to ten percent of the overall rock. Metals within the rock are thus confined to the veins and are coarser and higher grade than would be expected when looking at just the average grade.
Average assay grades for the three zones of the samples are show in the table below:
____ ———————————————————— ____ ———————————————————— ____ Zone______ number__ weight____ MoS2______ Mo______Cu______Ag ____ ———————————————————— ____ name____intervals______kgs________%________%______ %____ g/t ____ ———————————————————— ____ ———————————————————— ____ Cu-Ag__________25____166.6____0.031____0.019____0.17____4.15 ____ ———————————————————— ____ Cu-Mo__________41____274.7____0.067____0.040____0.12____2.82 ____ ———————————————————— ____ Mo____________ 49____304.2____0.174____0.104____0.03____1.06 ____ ———————————————————— ____ ————————————————————
Samples were selected in continuous intervals to represent the volume and grade distribution within the overall deposit. It should be noted that SGS maintains an extensive database of mines from around the world for comparison purposes on certain of the tests.
Over the next few weeks the remaining tests will be completed and include the following:
– Lock cycle testing to improve recoveries from the flotation cycle
– 10 kg cleaner flotation testing in bulk form to obtain recoveries by treating the zones as a single sample
– Obtaining the potential recoveries of Tungsten(W) and Gallium(Ga) from the tailings of the flotation process
– Obtaining a complete analysis of the concentrates including Rhenium and Osmium
– Determining the chemical make-up of the final tailings from the circuit
– Outlining a potential mill flow sheet for the deposit.
Once completed, a final report will be submitted and filed on Sedar. This is expected within the next five weeks. The recoveries from the final report will be built into the block model and all drill hole intersections. This will provide an in-ground recoverable metal value that can be used for cutoff grades and assay averages to simplify the process of publishing results.
Detailed Results of the Metallurgical Testing
The Flotation Studies consisted of two levels, rougher and cleaner flotation.
The rougher flotation study results are displayed below:
____ —————————————————- ____ —————————————————- ____ Zone____________Grind________________Recovery ____ —————————————————- ______________ microns__ mesh______ Cu______ Mo______ Ag ____ —————————————————- ____ —————————————————- ____ —————————————————- ____ Cu-Ag__________63____250____72.66%__ 85.77%__ 75.82% ____ —————————————————- ____ Cu-Ag________ 125____120____58.72%__ 81.56%__ 70.30% ____ —————————————————- ____ —————————————————- ____ Cu-Mo__________63____250____89.31%__ 92.92%__ 74.51% ____ —————————————————- ____ Cu-Mo________ 125____120____89.72%__ 92.37%__ 73.99% ____ —————————————————- ____ —————————————————- ____ Mo____________ 63____250____76.96%__ 94.42%__ 64.35% ____ —————————————————- ____ Mo____________125____120____83.12%__ 96.94%__ 71.82% ____ —————————————————- ____ —————————————————-
Note: the finer grind demonstrated better results on the copper, especially in the Cu-Ag zone. Since copper is only a by-product, work will be done later to determine the cost benefit of finer grinding to improve the recoveries.
Using a 2 kg sample and only three cleaning stages, results for the cleaner flotation study are displayed below:
________- Cu-Ag zone produced a Cu concentrate assaying: ____________ 15.3% Cu, 2.3% Mo and 462 gms Ag/T at ____________ 64% Cu, 97.5% Mo and 64.9% Ag recoveries ________- Cu-Mo zone produced a Cu-Mo Concentrate assaying: ____________ 18.0% Cu, 6.3% Mo and 344 gms Ag/T at ____________ 85.5% Cu, 93.7% Mo and 76.8% Ag recoveries ________- Mo zone produced a Mo concentrate assaying: ____________ 5.94% Cu, 24.4% Mo and 151 gms Ag/T at ____________ 91.1% Cu, 94.9% Mo and 93.9% Ag recoveries.
Although preliminary in nature, the flotation studies indicate that the material has good cleaning characteristics and that further cleaning and separation will yield saleable Cu (greater than 20% Cu) and Mo (greater than 50% Mo) concentrates. It should be noted that Mosquito is planning to have its own molybdenum roaster for its CUMO project, allowing it to produce saleable technical molybdenum oxide from the Mo concentrate while recovering valuable rhenium, osmium and sulphuric acid for additional revenues. The copper concentrate will be sold to smelters.
The QEMSCAN Mineralogical Study was performed to determine what minerals are present and the presence of any potential problematic minerals in the processing circuit. The results from all three CUMO zones were excellent, showing no problematic minerals and that the recovery process should be relatively straightforward with no need for expensive reagents in the mill circuit. Results are summarized as follows:
– All three CUMO zones were found to be largely free of any of fine grained clays or talc, indicating that no processing problems should be expected. The presence of clay minerals and talc can cause problems with recoveries and also poor water quality in the tailings. They often lead to expensive reagents having to be added to the mill process.
– Copper mineralization is chalcopyrite with very little oxide and is finer grained than the molybdenum. Optimum grind size for the molybdenum is 70 to 80 microns while for the copper it is 65 microns.
– Pyrite content of the CUMO zones is very low compared to other deposits of this type, resulting in significant costs savings as the amount of reagents required to handle the pyrite is reduced. For example, the Thompson Creek molybdenum mine located only 100 kms from CUMO, has specific circuits added to the mill site to handle the pyrite, adding to the cost to produce product.
A Grindability Study was conducted to give an indication as to how easy it is to crush the rock. The higher the numbers, the more it costs in terms of power and time to produce the grind required to recover the final products. In the case of CUMO, the results for all three samples were found to be well within the average of existing large scale open pit mines. It should also be noted that the molybdenum zone is softer and consumes 20% less power than the other two zones. The Bond Ball Mill Work Index Values, which is a measure of “grindability” in terms of kilowatt hours per ton (power consumption), were as follows:
____________________ —————————– ____________________ —————————– ____________________ Zone______ Metric____Imperial ____________________ —————————– ____________________ name____kWh/tonne____ KWh/ton ____________________ —————————– ____________________ —————————– ____________________ Cu-Ag________15.8________14.3 ____________________ —————————– ____________________ Cu-Mo________15.7________14.3 ____________________ —————————– ____________________ Mo__________ 12.6________11.4 ____________________ —————————– ____________________ —————————–
Mr. Shaun M. Dykes, M.Sc. (Eng), P.Geo., Exploration Manager and Director of Mosquito is the designated qualified person for the CUMO Project, and prepared the technical information contained in this news release.
On Behalf of the Board
MOSQUITO CONSOLIDATED GOLD MINES LTD.
Brian McClay, President
About Mosquito Consolidated Gold Mines
Mosquito Consolidated Gold Mines Limited is a mining exploration and development company with a diverse portfolio of high potential precious and base metals projects, located in low political risk environments in North America and Australia. The Company’s primary focus is developing its Idaho-based CUMO project, one of the world’s largest molybdenum deposits, and its Nevada-based Pine Tree copper- molybdenum-silver project. For more information, please visit www.mosquitogold.com.
THIS NEWS RELEASE WAS PREPARED BY MANAGEMENT WHO TAKES FULL RESPONSIBILITY FOR ITS CONTENTS.
This news release includes certain statements that express management’s expectation or estimates of future performance and may be deemed “forward-looking statements”. These forward-looking statements include plans, estimates, forecasts and statements as to management’s expectations regarding the CUMO Project. These forward- looking statements involve assumptions, risks and uncertainties and actual results may vary materially. For these reasons shareholders should not place undue reliance on such forward-looking information.
United States residents are cautioned that some of the information that may be published by Mosquito may not be consistent with United States Securities and Exchange Commission disclosure rules and may be materially different from what the Company is permitted to disclose in the United States and therefore United States residents should not rely on such information.
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