お知らせ • Jul 22
Bell Copper Corporation Receives Preliminary Report of Metallurgical Testing At Big Sandy Project in Arizona
Bell Copper Corporation received a preliminary report of metallurgical testing of the most copper- rich interval of drillhole BS-3 at its Big Sandy project in Arizona. Big Sandy is a large, truncated porphyry copper-molybdenum target located in northwestern Arizona, approximately 30 kilometers south of the Company's analogous Perseverance Project. Drillhole BS-3 cut 200 meters from 1302 meters to 1502 meters grading 0.42% copper (8.4 lbsCu/st)and 2.4 grams of silver per tonne as supergene chalcocite hosted in strongly pyritic, sericitized porphyry. The hole was terminated in strongly pyritic, sericitized porphyry at an inclined depth of 2026.33 meters when the mechanical limits of the drill were reached. A composite sample of coarse assay rejects from the chalcocite-bearing (copper-bearing) interval 1302- 1502 meters was shipped to SGS Canada Inc. (Lakefield site located in Ontario) [SGS] for a bank of scoping metallurgical studies. The chalcocite was tested for its amenability to recovery by both froth flotation and acid leaching. Molybdenite was tested for its amenability to concentration by froth flotation and for itscontent of the strategic element rhenium. The grade of the composite sample as received by SGS was 0.41% Cu, 0.005% Mo, 2.3 g/t Ag, and 4% S. The concentrations of deleterious elements As, Pb, Sb, and Zn were all less than 50 parts per million. Mineralogically, 75% of the copper in the sample was chalcocite, while another 15% was bornite, and the remainder was comprised of other sulfide copper minerals. Oxide copper minerals were negligible. Pyrite accounted for approximately 8% of the sample. Quartz at 52% and muscovite at 34% were the dominant non-sulphide species. Carbonate minerals constituted 0.1% of the sample. A conventional froth flotation approach was found to be successful at recovering and concentrating the value minerals. Batch test copper recovery of 82-84% into a concentrate grade of 25% Cu was achieved. At a bulk cleaner concentrate grade of 25% Cu, silver grade was approximately 130 g/t while recovery was approximately 68%. Silver appeared to track with copper. Low molybdenum feed grade made it difficult to produce a Mo concentrate, but in a best test, a Mo cleaner concentrate graded 20.7% Mo. Further testwork on larger amounts of sample is required to improve upon Mo results. The rhenium grade was assayed in a lower grade Mo concentrate and providing it tracks with molybdenum, rhenium is estimated to concentrate to approximately 1,700 g/t Re in a Mo concentrate grading 50% Mo. Ferric leaching in 30 g/L sulphuric acid was evaluated on whole ore ground to a P80 of 120 µm. The ore was amenable to leaching with copper extraction in the range of 96%. The pyrite intrinsic to the sample contributed additional free acid over the course of the leaching experiments. In one phase of the testing, chalcocite (copper sulfide) was recovered via froth flotation employing standard reagents used in operating copper mills. The purpose of this testing was to 1) determine the % age of copper that can be recovered using this common technique, 2) determine the copper gradeof the resulting concentrate, and 3) assess the concentration of byproduct metals and deleterious elements in the concentrate. Batch test copper recovery of 82-84% into a concentrate grade of 25% Cu was achieved. Opportunities exist to increase the concentrate grade by depressing clean pyrite. At a bulk cleaner concentrate grade of 25% Cu, silver grade was approximately 130 g/t Ag while recovery was approximately 68%. Silver appeared to track with copper. Final multi-element analysis of the concentrate is pending. The resulting copper concentrate from the test work are now available for discussions with copper smelting companies. The BS-3 chalcocite sample was also subjected to acid leach testing in order to determine if the Big Sandy chalcocite might be amenable to solution mining extraction. This testing is not meant to evaluate whether copper recovery via in-situ mining is feasible, but rather to determine at this early stage of evaluation if any mineralogical factors would prohibit it. This test work showed that copper extraction in the range of 96% from whole ore ground to a P80 of 120 µm is possible. The tests also showed the positive effect that, rather than consuming expensive acid, the test leaching process generated free acid over the course of the leaching experiments due to the oxidation of pyrite intrinsic to the sample. At a molybdenite grade of 0.005% Mo, the sample interval did not contain abundant molybdenite, though it was desired to test its amenability to froth flotation and separability from the copper concentrate. The low abundance of molybdenite made the test work difficult, but in a best test, a Mo cleaner concentrate was produced that graded 20.7% Mo. Further testwork is required to improve upon Mo results. Additionally, the rhenium content of the best molybdenite concentrate from the testing was determined to assess the potential for a credit at Big Sandy from this strategic metal. Molybdenite from drillhole BS- 1, located 1.2 kilometers east of BS-3, was geochronologically dated at the Colorado State University Airie Laboratory using the rhenium-osmium dating technique. That dating exercise revealed an unusually high content of rhenium in the Big Sandy BS-1 molybdenite of 8713 ± 17 ppm to 9319 ± 25 ppm. The rheniumgrade was assayed in a lower grade Mo concentrate from BS-3 and, providing it tracks with molybdenum, rhenium is estimated to concentrate to approximately 1,700 g/t Re in a Mo concentrate grading 50% Mo. High rhenium grades in both the BS-1 molybdenite and the BS-3 molybdenite, with 1.2 kilometers separating these two drill intersections, suggest that elevated rhenium is an intrinsic feature of the Big Sandy porphyry system. In the final report, high definition TIMA-X technology will be used to image the BS-3 material and determine the identity, size, and microscopic texture of the minerals hosting the target metals. This imagery will assist in optimizing grind size, reagent selection, upgrading of concentrate, and the deportment of any potential byproduct or deleterious elements.
