News Releases
| Thu Apr 12, 2007 Bear Creek Announces Positive Leach Test Results at Santa Ana Project; Phase III Drill Program Will Further Delineate Potential for Large Tonnage, Low Cost Silver Resource | |
| Vancouver, B.C. - Bear Creek Mining (TSX Venture: BCM) ("Bear Creek" or the "Company") is pleased to announce the positive test results performed and confirmed by three separate laboratories on 10 representative samples from the Santa Ana Silver deposit. The samples were selected from five diamond drill holes spaced throughout the area of mineralization at various depths from the deposit representing average grade ranges indicated by the reconnaissance drilling. Andrew Swarthout, President/CEO stated "As we anticipated from the dominance of oxide silver mineralization observed to the depths drilled, the test work confirms that the Santa Ana material responds very well to cyanide leaching. Given the guidance from the preliminary metallurgical work and the size of the under-explored silver anomaly; Santa Ana has excellent potential to be a low-cost, heap leach, pure-silver deposit. Santa Ana is becoming an exciting addition to Bear Creek's discovery stream." Given the positive leach testing results, Phase 3 drilling comprised of 2,500 meters will commence on April 17th. This program is designed to evaluate the bulk-tonnage, low cost heap leaching potential of the Santa Ana silver deposit using lower cut-off grades, as well as expanding the higher-grade intercepts, which remain open along the limits of the anomaly. METALLURGICAL TESTING Preliminary cyanide leach amenability tests were performed at ALS-Chemex, Lima, Peru where the ten samples were agitated for 24 hours. As previously reported, the results indicated that leaching would perform well and that further testing was warranted (see news release 2 March '07). Subsequent testing was performed by Plenge Labs, Lima, Peru and, McClelland Labs, Sparks, Nevada on ground core samples (coarse assay rejects) from the same ten drill hole samples. Cyanide and pH were monitored throughout the test periods in order to maintain the proper test conditions. Plenge Laboratory Test Summary The samples were ground to approximately 50% passing 200 mesh (76µm) and bottle roll tested for 96 hours under supervision of Adam Johnston of Transmin (a consulting metallurgist for the Company). The tests showed silver recoveries ranging from 72% to 96% Ag with an average of 85%. These results are indicative of potential recoveries in a vat leach recovery plant suitable for the treatment of higher-grade material. McClelland Laboratory Test Summary Bottle roll tests were performed on material from the same ten drill hole intervals at McClelland Labs in Sparks, Nevada. The material was crushed to 70% passing 2mm material and was leached for 168 hours. The tests show the average recovery of silver on this coarser material to be 71% and ranges from 54% to 88%. Importantly, recoveries were still increasing when the testing was terminated. These results give guidance on potential leach recoveries at coarser crush size. Phase II Metallurgical Testing The test results indicate excellent potential for a "Pulp Agglomeration" heap leaching technique; a method where higher grade material is milled and vat leached to achieve higher recoveries, then mixed with crushed lower grade material and placed in a heap leach. McLelland Labs has commenced a column leach test program to evaluate expected recoveries in actual heap leach conditions and define optimal crush size as well as the cyanide and lime consumption. The testing involves three- 6 inch by 10' columns utilizing approximately 300 kg of drill core from the same drill hole intervals so that comparisons can be made to bottle roll leach performance. Column leaching is a long-term test intended to predict heap leach performance; results are expected in 2-3 months. The TSX Venture Exchange does not accept responsibility for the adequacy or accuracy of this release. - End - Andrew Swarthout - President and CEO, or Patrick De Witt - Investor Relations Phone: 604-685-6269 Direct: 604-628-1111 E-mail: info@bearcreekmining.com For further information, please visit the Company's website (www.bearcreekmining.com) Regulatory footnotes: All of Bear Creek's exploration programs and pertinent disclosure of a technical or scientific nature are prepared by or prepared under the direct supervision of David Volkert, P.Geo., Bear Creek's Vice President of Exploration or Marc Leduc, P. Engr., Vice President Technical Services, and the President and CEO, Andrew Swarthout, P.Geo., the President and Chief Executive Officer, who serve as the Qualified Persons under the definitions of NI 43-101. All diamond drilling has been performed using HQ diameter core with recoveries averaging greater than 95%. Core is logged and split on site under the supervision of Bear Creek geologists. Sampling is done on two-meter intervals and samples are transported by Company staff to Cusco, Peru for direct shipping to ALS Chemex, Laboratories in Lima, Peru. ALS Chemex is an ISO 9001:2000-registered laboratory and is preparing for ISO 17025 certification. Silver, lead, and zinc assays utilize a multi-acid digestion with atomic absorption ("ore-grade assay method"). The QC/QA program includes the insertion every 20th sample of known standards prepared by SGS Laboratories, Lima. A section in Bear Creek's website is dedicated to sampling, assay and quality control procedures. Certain disclosure in this release, including management's assessment of Bear Creek's plans and projects, constitutes forward-looking statements that are subject to numerous risks, uncertainties and other factors relating to Bear Creek's operation as a mineral exploration company that may cause future results to differ materially from those expressed or implied in such forward-looking statements. *Any reference to the potential quantity & grade of mineralization is conceptual in nature, there has been insufficient exploration to define a mineral resource on the property and it is uncertain if further exploration will result in discovery of a mineral resource on the property. Readers are cautioned not to place undue reliance on forward-looking statements. Bear Creek expressly disclaims any intention or obligation to update or revise any forward-looking statements whether as a result of new information, future events or otherwise. | |