TORONTO, July 9, 2019 /CNW/ - Anaconda Mining Inc. ("Anaconda" or the "Company") (TSX: ANX) (OTCQX: ANXGF) is pleased to announce that a metallurgical test program (the "Met Program") that is being conducted as part of the planned feasibility study for the Goldboro Gold Project ("Goldboro", or the "Project") has returned extremely high processing recoveries in a range of 87%-99%. The Met Program was completed at Base Metallurgical Laboratories Ltd. in Kamloops, BC and under supervision of Ausenco Engineering Canada Inc., which is leading the Goldboro mineral processing plant design.
Highlights of the metallurgical testing program include:
"We are excited to see that the metallurgical testing completed to support the Goldboro feasibility Study is confirming even higher recoveries than testing performed in 2017 as part of the previously released positive Preliminary Economic Analysis. This is a very important milestone that paves the road to finalizing the Goldboro plant design and overall project feasibility, which is expected to be completed mid Q4 2019. We look forward to further progress in 2019 with the continuation of permitting, with the aim of obtaining the requisite permits to begin construction in 2020."
~ Kevin Bullock, Chief Executive Officer, Anaconda Mining Inc.
The objective of the Met Program was to determine a flow sheet that optimizes gold recovery while minimizing reagent consumptions via gravity processing followed by leaching, as well as to assess the effect of grind on gold recovery by gravity and leach-CIP processes. The Met Program included comminution testing, grind optimization, gravity concentration, leach testing, cyanide destruction and arsenic precipitation. Cyanide destruction and arsenic precipitation development was also completed to generate samples for environmental and geotechnical characterization studies in support of continued environmental permitting. No deleterious elements were found within the Goldboro samples which contained approximately 3% sulphide minerals.
Anaconda obtained seven samples from the Boston Richardson (Low, Medium and High Grade) and East Goldbrook (EG1, EG2, EG3 and EG4) mineral resource areas and made composites by grade and to spatially represent their respective resource areas. The gold feed grades of the samples, determined by screened metallics protocol, ranged from 0.6 grams per tonne ("g/t") to 12 g/t Au. The purpose of testing a wide range of gold grades was to ascertain plant recoveries over the entire project life as grades will be relatively lower during the open pit mining period as compared to the higher-grade underground mining portion, which represents the majority of the mine life.
Crushing and Grinding Testing:
Detailed comminution testing characterized ore hardness by Bond Low Energy Impact Crushing Work Index (CWI), SMC Test, and Bond Rod Mill Work Index (RWI), Bond Ball Mill Work Index (BWI) and Bond Abrasion Index (AI). The composites tested fell in the range of 36.8 to 79.4 A x b through SMC tests, with a Bond Ball Mill Work Index median of 15.7 kWh/t which spanned the medium to medium hard range of hardness.
Samples from the Boston Richardson zone were tested with the Extended Gravity Recoverable Gold (E-GRG) protocol to determine their amenability to gravity concentration. The results showed very high Gravity Recoverable Gold (GRG) numbers, which ranged from 78 to 98% Au. The GRG value does not directly predict or correlate gold recovery results from a closed-circuit milling operation. It is indicative of gravity gold amenability and in this scenario all three samples would benefit from the inclusion of a gravity circuit.
Leach conditions were evaluated over a range of grind sizes (from 80% passing 250 μm to 80% passing 60 μm) and leach retention times up to 48 hours. Leach tests were preceded by batch gravity concentration to replicate plant conditions. The optimal grind size was found to be 80% passing 100 to 110 μm. Leach recovery was not overly sensitive to fineness of grind. Under optimized conditions (cyanide maintained at 0.5 g/L as NaCN) reagent consumption is low, with sodium cyanide (NaCN) and lime (CaO) averaging 0.14 kg/t and 0.53 kg/t, respectively.
Initial kinetic screening tests include batch gravity recoveries ranging from 8% Au to 97% Au and overall leach recoveries ranging from 86% to 98% for overall recoveries ranging from 87% Au to 99% Au. Leach tests were run over 48 hours.
Optimization Testing and Detailed Results:
Optimization tests were run at the optimal grind and at reduced cyanide concentrations of 0.5 g/L NaCN at 50% solids for 24 to 36 hours. The results show in the table below combined gravity/leach gold extractions of 94% Au to 99% Au with a final residue values of 0.07 g/t Au to 0.46 g/t Au for the Boston Richardson Ore types and 87 to >99% with final residues 0.04 g/t Au to 0.20 g/t Au for East Goldbrook samples. Calculated head grades ranged from 5.0 g/t Au to 17.1 g/t Au for the Boston Richardson samples and from 0.90 g/t Au to 21 g/t Au for the East Goldbrook samples. The metallurgical testing shows an increase of 44 % in the calculated head grade versus samples Screen Metallics.
Screen Metallics Head Grade
Calc. Head Grade
Leach Kinetics (hours)
The Bulk Composite was assembled from the Boston Richardson samples and three of the East Goldbrook samples (EG1, EG2 and EG3) to provide a large sample for continuous cyanide destruction tests.
Plant recoveries for the Feasibility Study will be estimated using grades from the Mine Plan along with typical plant losses.
Cyanide destruction using the SO2/air method testing with batch and continuous testing demonstrated that a weak acid dissociable cyanide (CNWAD) below 3 mg/L could be achieved with 45 minutes of retention time using a conventional ratio of 5g SO2/g CNWAD.
Arsenic precipitation of the Cyanide Destruction product with ferric sulphate reduced arsenic in solution to below 0.5 mg/L and less than 0.1 mg/L can be attained. Addition rates of ferric sulphate were in line with industrial practice at 10:1 iron to arsenic. This testing confirms that cyanide destructions and arsenic removal systems would achieve water quality that meets the Federal Environmental Code of Practice for Metal Mines and the Metal Mining Effluent Regulations (MMER) discharge criteria.
This news release has been reviewed and approved by Robert Raponi, P. Eng. of Ausenco Engineering Canada Inc., a "Qualified Person", under National Instrument 43-101 Standard for Disclosure for Mineral Projects.
Anaconda is a TSX and OTCQX-listed gold mining, development, and exploration company, focused in Atlantic Canada. The company operates mining and milling operations in the prolific Baie Verte Mining District of Newfoundland which includes the fully-permitted Pine Cove Mill, tailings facility and deep-water port, as well as ~11,000 hectares of highly prospective mineral lands including those adjacent to the past producing, high-grade Nugget Pond Mine. Anaconda is also developing the Goldboro Gold Project in Nova Scotia, a high-grade resource and the subject of an on-going feasibility study.
This news release contains "forward-looking information" within the meaning of applicable Canadian and United States securities legislation. Forward-looking information includes, bit is not limited to, information with respect to the Offering, the use of proceeds and the TSX acceptance of the Offering. Generally, forward-looking information can be identified by the use of forward-looking terminology such as "plans", "expects", or "does not expect", "is expected", "budget", "scheduled", "estimates", "forecasts", "intends", "anticipates", or "does not anticipate", or "believes" or variations of such words and phrases or state that certain actions, events or results "may", "could", "would", "might", or "will be taken", "occur", or "be achieved". Forward-looking information is based on the opinions and estimates of management at the date the information is made, and is based on a number of assumptions and is subject to known and unknown risks, uncertainties and other factors that may cause the actual results, level of activity, performance or achievements of Anaconda to be materially different from those expressed or implied by such forward-looking information, including risks associated with the exploration, development and mining such as economic factors as they effect exploration, future commodity prices, changes in foreign exchange and interest rates, actual results of current production, development and exploration activities, government regulation, political or economic developments, environmental risks, permitting timelines, capital expenditures, operating or technical difficulties in connection with development activities, employee relations, the speculative nature of gold exploration and development, including the risks of diminishing quantities of grades of resources, contests over title to properties, and changes in project parameters as plans continue to be refined as well as those risk factors discussed in Anaconda's annual information form for the year ended December 31, 2018, available on www.sedar.com. Although Anaconda has attempted to identify important factors that could cause actual results to differ materially from those contained in forward-looking information, there may be other factors that cause results not to be as anticipated, estimated or intended. There can be no assurance that such information will prove to be accurate, as actual results and future events could differ materially from those anticipated in such information. Accordingly, readers should not place undue reliance on forward-looking information. Anaconda does not undertake to update any forward-looking information, except in accordance with applicable securities laws.
SOURCE Anaconda Mining Inc.