Bell Copper Reports Big Sandy Metallurgy
July 21, 2022
Bell Copper Corporation
Bell Copper Reports Big Sandy Metallurgy
VANCOUVER, B.C. - Bell Copper Corporation (TSXV:BCU) (OTCQB:BCUFF)(“Bell Copper” or the “Company”) reports that it has 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 percent 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 its content 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.
Highlights of the test work include:
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.
Once the final report is received from SGS, it will be posted on the Company’s website.
Metallurgical Test Work
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 percentage of copper that can be recovered using this common technique, 2) determine the copper grade of 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 rhenium grade 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.
Figure A. Core from BS-3 (1304 m) showing disseminated chalcocite (bright white) in strong quartz-sericite altered porphyry.
Figure B. Core from BS-3 (1364.5 m) showing dark chalcocite-bornite veinlets cutting coarse-grained pyrite veinlet in quartz- sericite altered porphyry.
Tim Marsh, Bell’s President and CEO, and a Qualified Person as defined by NI43-101, said,
“A first look at the metallurgical characteristics of the Big Sandy porphyry suggests that Bell should be considering multiple extraction alternatives as we pursue this exciting, ongoing discovery. This work shows that either conventional froth flotation or leaching is a candidate recovery method for the copper mineralization encountered in BS-3. Opportunities for fine-tuning of processes exist, but the initial effort to make a 25% copper concentrate at 82-84% recovery yielded a product that is attractive to copper smelters. If future engineering studies show that extraction via underground mining is unfavorable, the leaching studies suggest that in-situ extraction might be a feasible alternative. And for the second time in the opening days of this discovery story, elevated rhenium content of molybdenite in the BS-3 metallurgical sample, like the high rhenium content of molybdenite that was age-dated 1200 meters away in drillhole BS-1, suggests that high levels of the strategic metal rhenium is a hallmark of the Big Sandy porphyry system.”
Sampling and Quality Control
A single 100-kilogram composite sample of the BS-3 chalcocite intersection (1302m to 1502m) was produced by combining assay reject material returned from the original assaying campaign at Skyline Laboratories in Tucson, Arizona. Three-eighths splits through a Jones-type splitter of each original assay sample were combined to produce the composite sample. This compositing work was conducted under the direct supervision of the Company’s Qualified Person. Three buckets containing the 100-kilogram sample were shipped to SGS Lakefield Lab in Ontario, where SGS Lakefield staff blended the three buckets into a homogeneous sample before splitting into aliquots for metallurgical test work.
About Bell Copper
Bell Copper is a mineral exploration company focused on the identification, exploration and discovery of large copper deposits located in Arizona. Bell Copper is exploring its 100% owned Big Sandy Porphyry Copper Project and the Perseverance Porphyry Copper Project which is under a Joint Venture - Earn In.
The technical content of this release has been reviewed and approved by Timothy Marsh, PhD, PEng., the Company’s CEO and President. No mineral resource has yet been identified on the Big Sandy Project. There is no certainty that the present exploration effort will result in the identification of a mineral resource or that any mineral resource that might be discovered will prove to be economically recoverable.
On behalf of the Board of Directors of
Bell Copper Corporation
Timothy Marsh, President, CEO & Director
For further information please contact the Company
Tel: 1 800 418 8250
Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.