NORTH AMERICAN LEADER IN PGM AND LITHIUM EXPLORATION
River Valley PGM Project with 2.9Moz Palladium Equivalent (Measured & Indicated) Advancing to Pre-Feasibility Study
Message: PFN News!
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Pacific North West Capital Reports Positive Platinum Metal Concentration Results for River Valley PGM Project near Sudbury, Ontario |
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VANCOUVER, April 10, 2013 - Pacific North West Capital Corp. (TSX: PFN; OTCQX: PAWEF; Frankfurt: P7J) is pleased to report positive metallurgical testwork results for drill core composites from its 100% owned River Valley PGM deposit, near Sudbury in Ontario. The testwork completed by SGS Canada Inc. (SGS) of Lakefield, Ontario, involved Bond grindability and abrasion studies, sample compositing, physical and chemical analyses, and bench scale flotation tests to make high-grade sulphide concentrate. Results show that the platinum group metals (PGM) float with copper-nickel sulphides, and therefore demonstrate potential for a sulphide concentrator to effectively process River Valley deposit material. SGS recommend additional testwork to determine the optimal grind size for PGM separation and further improve concentrate grade and metal recovery. A copy of the SGS report is available for viewing on the Company's website. "PFN is very encouraged by these initial metallurgical results, which demonstrate good metal recoveries from the River Valley PGM deposit", said Dr. William Stone, President & COO. "The results are close to North American Palladium's Lac des Iles Mine results during operation of their big open pit mine. However, more extensive testwork on River Valley is required to improve metal recoveries. The PGM mineralization extends for 10 km along strike and shows high-grade pods, patches and domains which extend from surface to the depth of drilling, generally less than 250 metres deep. In evaluating the metallurgical results, the Company plans to follow-up with expanded testwork and larger sampling programs to further advance River Valley towards a Preliminary Economic Assessment study". TESTWORK RESULTS Metallurgical testwork was carried out on an Overall Composite sample prepared from half-core intervals from the Dana North Zone (DNZ) and the Dana South Zone (DSZ) of the River Valley PGM deposit (Figure 1). Testwork involved mineralogical and chemical analysis, Bond Rod and Ball mill grindability, and Bond abrasion testing on each of the Dana North and Dana South Zone composites. Mineralogical analysis determined that the main minerals are amphibole/pyroxene and plagioclase, consistent with gabbro-norite intrusive host rock type. Chalcopyrite is the sole copper mineral phase and pentlandite the primary nickel sulphide phase. However, sulphides hold only 35% to 45% of the total nickel; the remaining percentage is held in silicates and therefore unrecoverable. The Bond rod mill grindability tests at 14 mesh of grind (1180 micrometres) identified each of the two composites as very hard, with Rod Mill Work Index at ~20.0 kWh/t. A Bond ball mill grindability test at 150 mesh (106 micrometres) identified each of the two composites as hard to very hard, with a Ball Mill Work Index of 18.8 kWh/t for DNZ and 19.5 kWh/t for DSZ. The Bond Abrasion tests determined each composite to be in the moderate to hard abrasive range. Flotation testwork was completed on the Overall composite in order to: 1) develop a viable flowsheet; 2) evaluate parameters such as primary grind and regrind fineness, reagents and dosages; and 3) generate a concentrate that targeted a grade of ~200 g/t PGM. Eleven rougher kinetics tests were performed to evaluate effective reagents, dosages, flotation time and primary grind fineness. Cleaner tests were undertaken to investigate cleaner circuit configuration, depressants and regrind fineness. The best test produced a concentrate grading 8.94% copper, 1.22% nickel and 109 g/t PGM at recoveries of 86.8% for copper, 26.7% for nickel and 73.1% for PGM. A single locked cycle test (LCT) was completed applying the flowsheet and conditions of the final cleaner test (Figure 2). The primary grind was at P80 = 71 µm and the regrind at P80 = 19 um. The LCT produced a concentrate grading 15.5% copper, 1.67% nickel and 189 g/t PGM at recoveries of 84.4% copper, 22.2% nickel and 68.7% PGM (Table 1). The 3rd cleaner concentrate from the LCT was submitted for multi-element analysis. In addition to platinum, palladium, gold, copper and nickel, which would all be payable, rhodium, cobalt and silver are present a levels which are likely also be payable. Conversely, contents of magnesium, arsenic, antimony, bismuth, and selenium are all below the problematic limits for marketability. RECOMMENDATIONS SGS make the following recommendations for further testwork on River Valley: 1. Further investigate the effect of primary grind size on flotation recovery; 2. Flotation optimization testing in order to achieve further improvement of concentrate grade and metal recovery; and 3. Flotation and grindability variability testing on the composite samples in order to identify the variability of flotation performance. Subsequently, variability testing should be extended to investigate a broader range of samples from each of the mineralized zones at River Valley, to investigate the effect of feed grade and rock type on metallurgy. |
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