(TheNewswire)
Toronto, ON - TheNewswire - June 1, 2023 - AbraSilver Resource Corp. (TSX.V:ABRA ) ( OTC:ABBRF) (“AbraSilver” or the “Company”) is pleased to report positive preliminarymetallurgical test results for the new JAC zone at its wholly-ownedDiablillos property in Salta Province, Argentina (“Diablillos” orthe “Project”). The program was completed by independentmetallurgical consultants, SGS Canada Inc., at their testingfacilities in Lakefield, Ontario.
Key Highlights Include:
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Overall recoveries at the JAC and Fantasma depositsrange between 86% - 93% forsilver and 82% - 91% for gold.
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A substantial percentage of the silver at JAC can berecovered by gravity separation which increases overallrecoveries.
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Current testwork confirms that the same processflowsheet can be used to process mineralization from the Oculto, JACand Fantasma deposits.
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Milling tests have shown that 150 microns is thetargeted grind size for the leaching of the mineralized material at aretention time of 36 hours.
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Overall silver and gold recoveries could likely beincreased further by grinding finer and with higher cyanideconcentrations. Further metallurgical testwork and trade-off studiesare now underway.
John Miniotis, President and CEO, commented, “We areextremely pleased that the metallurgical testwork results at JACdemonstrate excellent recovery rates for both silver and gold. Theseresults show that mineralization at JAC responds very well toconventional processing and recovery technologies, providing highlypositive implications for the future development potential of theproject. The results will be incorporated into our Mineral Resourceestimate and Pre-Feasibility Study which remain on track to bedelivered later this year.”
Favorable Recovery Rates vs. PriorTestwork
At the JAC and Fantasma deposits the silver minerals (chlorargyrite and iodargyrite) are easier to release by grinding, and are more sensitive to cyanide leaching as they occur inargillic alteration , whereas at Oculto they aremostly held more complexly in vuggy silica host rock.
Table 1 - Summary of MetallurgicalTestwork Results for JAC and Fantasma Deposits
Testwork on JAC and Fantasma samples showed thatgravity separation before cyanide leaching recovers approximately 9%of the silver and 17% of the gold
which, when combined with the subsequent cyanideleaching recoveries, results in total overall recoveries of between86% and 93% for silver and between 82% and 91% for gold.
Table 2 below shows gravity plus cyanide leachrecoveries at the JAC and Fantasma deposits compared with the Ocultodeposit recoveries announced in the PEA announced in January 2022.
Table 2 – Latest Metallurgical Testwork Results vs.Jan. 2022 PEA Study
1 Recoveryrates for Oculto PEA reflect the life of mine average as per thereport published on Jan. 13, 2022 titled “NI 43-101 PreliminaryEconomic Assessment Technical Report – Diablillos Project”
A median of 89.5% recoveries for silver and 86.5% forgold at JAC and Fantasma compare favourably against the 73.5% silverrecoveries and 86.0% gold recoveries used for the Preliminary EconomicAssessment (“PEA”) at Oculto. The mediansilver recovery of 89.5% relative to 73.5% for Oculto is particularlyrelevant because the mineralization at the JAC and Fantasma depositsis predominantly silver.
Figure 1 – Median Recoveries at theJAC & Fantasma Deposits Compared with the Oculto Deposit
JAC drill core samples for metallurgical testing wereselected to be volumetrically representative of the mineralisedsystem, being from the various zones of mineralisation along strikeand at depth, including high, medium and lower grades. Care was takennot to mix alteration zones so that geo-metallurgical domains can bedetermined.
Additional metallurgical testing is being conducted onsamples from different geo-metallurgical domains at Oculto in aneffort to boost overall recoveries, especially from areas with highsilver grades.
Metallurgical Test Program Overview
This campaign was the first metallurgical testworkprogram conducted on the new JAC zone, discovered in August 2022, andon the already known Fantasma deposit. W orkcompleted involved comminution, gravity, leaching and thickeningtestwork of fourteen variability composites with twelve from the JACzone and two from the Fantasma zone. The results will be incorporatedin the upcoming Mineral Resource estimate (“MRE”) update andPre-Feasibility Study (“PFS”) for the overall Diablillosproject.
The results confirm that the Diablillos project willhave a conventional silver/gold processing plantflowsheet incorporating crushing, grinding, gravity concentration andintense cyanidation circuit, cyanide leachingwith oxygen addition, counter current decantation (“CCD”) washingthickeners and Merrill-Crowe precious metal recovery from solutionfollowed by on-site smelting to doré bars.
A summary of the processing flow sheet for theDiablillos project is shown below.
Figure 2 – Simplified Process Flowsheet for theDiablillos Project
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Bulk mineralogical investigation determined thatquartz, alunite, and iron-oxides were the major mineral components ofthe samples, and it is demonstrated that most of the silver willrespond well to direct cyanidation. The JAC composite was used formost of the testing program, with average head grades of 0.11 g/t goldand 148 g/t silver.
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Response to standard gravity separation tests for therecovery of free silver and gold resulted in average recoveries of 9%and 17%, respectively. As a result, the overall gravity pluscyanidation recoveries achieved were 86% to 93% for silver and 82% to 91% forgold
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The following optimum whole ore cyanidation conditionswere established for the JAC composite and applied to the variabilitysamples:
• Grind size P80 of 150 ?m,
• 45% pulp density (w/w),
• pH of 10.5-11.0 (maintained with lime),
• 4 hours of pre-aeration with air sparging,
• air-sparging during leaching,
• Sodium cyanide (NaCN) concentration of 1.5 g/lmaintained for the first 12 hours of leaching and then allowed tonaturally decay for the remaining leach time.
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The testwork showed that silver and gold recoveriescould likely be further increased by grinding finer (P80 of 70 ?mversus 150 ?m) and by increasing cyanide consumption from 1.5 g/l to2.5 g/l. Further metallurgical testwork and trade-off studies will beconducted to confirm the optimum process route.
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Environmental assessment of the leach tailings samplesshowed the potential for acid generation in some samples. On-sitehumid cell testwork is planned and mitigating measures will bedesigned as part of the tailings management strategy.
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Settling/thickening and rheology tests were performedon the JAC composite cyanide leach and cyanide destruction residue,showing a fast-settling rate in response to tested flocculants. Counter Current Decantation (CCD)modelling was performed as well, resulting in a 4 stages CCD circuitproducing a final wash efficiency of 99.8%
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Cyanide leach tests will continue on the samples fromOculto, JAC and Fantasma to optimize recovery and leach time. Driversto improve recoveries will include stronger cyanide solutions, grindsize of the ore, and leaching residence times.
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As gravity separation was successful in concentratinggold and silver at the JAC deposit, it is proposed that additionaltesting of gravity separation in advance of cyanidation be carried outon mineralisation types at Oculto, where there are both gold andsilver dominant geo-metallurgical zones.
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At the Diablillos site, humid cell test work is ongoingto evaluate acid rock drainage generation from the cyanidationtailings under site conditions to support potential mitigatingmeasures in the tailings management strategy.
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Heap leaching test work will be conducted toinvestigate the possibility of recovering lower grade material.
About Diablillos
The 80 km 2 Diablillos property is located in theArgentine Puna region - the southern extension of the Altiplano ofsouthern Peru, Bolivia, and northern Chile - and was acquired from SSRMining Inc. by the Company in 2016. There are several known mineralzones on the Diablillos property, with the Oculto zone being the mostadvanced with over 120,000 metres drilled to date. Oculto is ahigh-sulphidation epithermal silver-gold deposit derived from remnanthot springs activity following Tertiarty-age local magmatic andvolcanic activity. Comparatively nearby examples of high sulphidationepithermal deposits include: Yanacocha (Peru); El Indio (Chile);Lagunas Nortes/Alto Chicama (Peru) Veladero (Argentina); and Filo delSol (Argentina).
The most recent Mineral Resource estimate for theOculto Deposit is shown in Table 3:
Table 3 - Oculto Mineral Resource Estimate – As ofOctober 31, 2022
Notes: Effective October 31, 2022. Mineral Resourcesare not Mineral Reserves and have not demonstrated economic viability.The Mineral Resource estimate is N.I. 43-101 compliant and wasprepared by Luis Rodrigo Peralta, B.Sc., FAusIMM CP(Geo), IndependentConsultant. The mineralization estimated in the Mineral Resource issub-horizontal with sub-vertical feeders and a reasonable prospect foreventual economic extraction by open pit methods. For additionalinformation please see Technical Report on the Diablillos Project,Salta Province, Argentina, dated November 28, 2022, completed byMining Plus, and available on www.SEDAR.com.
QA/QC and Core Sampling Protocols
AbraSilver applies industry standard explorationmethodologies and techniques, and all drill core samples are collectedunder the supervision of the Company’s geologists in accordance withindustry practices. Drill core is transported from the drill platformto the logging facility where drill data is compared and verified withthe core in the trays. Thereafter, it is logged, photographed, andsplit by diamond saw prior to being sampled. Samples are then bagged,and quality control materials are inserted at regular intervals; theseinclude blanks and certified reference materials as well as duplicatecore samples which are collected in order to measure samplerepresentivity. Groups of samples are then placed in large bags whichare sealed with numbered tags in order to maintain a chain-of-custody during the transport of thesamples from the project site to the laboratory.
All samples are received by the SGS offices in Saltawho then dispatch the samples to the SGS preparation facility in SanJuan. From there, the prepared samples are sent to the SGS laboratoryin Lima, Peru where they are analyzed. All samples are analyzed usinga multi-element technique consisting of a four-acid digestion followedby ICP/AES detection, and gold is analyzed by 30g Fire Assay with anAAS finish. Silver results greater than 100g/t are reanalyzed usingfour acid digestion with an ore grade AAS finish. Analytical resultsare statistically processed for final acceptance.
Qualified Persons
David O’Connor P.Geo., Chief Geologist forAbraSilver, is the Qualified Person as defined by National Instrument43-101 Standards of Disclosure for Mineral Projects, and he hasreviewed and approved the scientific and technical information in thisnews release.
About AbraSilver
AbraSilver is an advanced-stage exploration companyfocused on rapidly advancing its 100%-owned Diablillos silver-goldproject in the mining-friendly Salta province of Argentina. Thecurrent Measured and Indicated Mineral Resource estimate forDiablillos consists of 51.3 Mt grading 66g/t Ag and 0.79g/t Au,containing approximately 109Moz silver and 1.3Moz gold, withsignificant further upside potential based on recent explorationdrilling. The Company is led by an experienced management team and haslong-term supportive shareholders including Mr. Eric Sprott. Inaddition, AbraSilver owns a portfolio of earlier-stage copper-goldprojects including the La Coipita copper-gold project in the San Juanprovince of Argentina. AbraSilver is listed on the TSX-V under thesymbol “ABRA” and in the U.S. under the symbol “ABBRF”.
For further information please visit the AbraSilverResource website at www.abrasilver.com , ourLinkedIn page at , and follow us on Twitter at
Alternatively please contact:
John Miniotis, President and CEO
Tel: +1 416-306-8334
Cautionary Statements
This news release includes certain"forward-looking statements" under applicable Canadiansecurities legislation. Forward-looking statements are necessarilybased upon a number of estimates and assumptions that, whileconsidered reasonable, are subject to known and unknown risks,uncertainties, and other factors which may cause the actual resultsand future events to differ materially from those expressed or impliedby such forward-looking statements. All statements that address futureplans, activities, events or developments that the Company believes,expects or anticipates will or may occur are forward-lookinginformation. There can be no assurance that such statements will proveto be accurate, as actual results and future events could differmaterially from those anticipated in such statements. Accordingly,readers should not place undue reliance on forward-looking statements.When considering this forward-looking information, readers should keepin mind the risk factors and other cautionary statements in theCompany’s disclosure documents filed with the applicable Canadiansecurities regulatory authorities on SEDAR at www.sedar.com. Therisk factors and other factors noted in the disclosure documents couldcause actual events or results to differ materially from thosedescribed in any forward-looking information. The Company disclaimsany intention or obligation to update or revise any forward-lookingstatements, whether as a result of new information, future events orotherwise, except as required by law.
Neither the TSX Venture Exchange norits Regulation Services Provider (as that term is defined in thepolicies of the TSX Venture Exchange) accepts responsibility for theadequacy or accuracy of this news release
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