Metallurgical Update
Feb 02, 2010 09:01 ET
Astral Announces Encouraging Metallurgical Testwork on Drill Samples From Jumping Josephine
VANCOUVER, BRITISH COLUMBIA--(Marketwire - Feb. 2, 2010) -Astral Mining Corporation (TSX VENTURE:AA)(TSX VENTURE:AA.WT)(PINK SHEETS:AAMJF)("Astral" or "the Company") is pleased to report results of preliminarymetallurgical testwork on three composite samples from the JumpingJosephine Gold Property, Southern British Columbia. First-passflotation, gravity concentration and cyanide leach methods were allsuccessful at recovering gold. Flotation tests averaged 98% goldrecovery, combined gravity and leach tests averaged 94% gold recoveryand whole ore leach tests averaged 86% gold recovery with the mediumand high grade whole ore leach composites averaging 97% gold recovery.Significant additional testing is recommended to evaluate metallurgicalbehaviour at different grind sizes and test variability from within themineralized zone. Astral is very encouraged by the gold recoveriesachieved from the preliminary testwork.
Testwork wasconducted by G&T Metallurgical Services Ltd. of Kamloops, BritishColumbia and was designed to provide a preliminary indication ofJumping Josephine's amenability to standard modern gold extractionmethods. This work represents a small scale, early stage study on threesamples totalling 100 kilograms(kg) of mineralized material from the JJMain stockwork zone. Results from the study will help to aid inselection of a suitable flowsheet for treating mineralized materialduring bulk sample processing and will form a basis for furthermetallurgical testwork. The completion of a 10,000 tonnes(t) bulksample permit application at Jumping Josephine is underway.
Discussion of Testwork
Low,medium and high grade composites were sourced from coarse rejectmaterial stored at Astral's Castlegar facility, having been returnedfrom earlier analyses on halved HQ-sized drill core. Samples wereselected from specific drill intervals to best reflect three levels ofmineralization observed in the JJ Main stockwork zone. The low-gradecomposite (0.6 grams per tonne (g/t) gold) was composed of weaklyquartz veined intervals with generally <1% sulphide mineralization,medium (3.3 g/t gold) and high-grade (12.0 g/t gold) composites weredrawn from strongly quartz veined stockwork intervals with up to 5%sulphides including arsenopyrite and sphalerite. Visible gold flakeshave been observed in intervals similar to the ones sampled to make thehigh-grade composite.
Characterization of Samples
Testworkwas completed on three samples, low (0.6 g/t gold), medium (3.3 g/tgold) and high-grade (12.0 g/t gold). Head grade assay work wascompleted on duplicate samples from each of the three composites byscreened metallic analysis using a 150 micron screen. Medium andhigh-grade samples returned a high level of screen oversize goldindicating the presence of coarse gold. Additional assays wereconducted on four size fractions from each composite. Sizing work fromthe medium and high-grade samples showed elevated gold in the 0.42-0.82millimeter size fraction whereas the low-grade sample showed a moreuniform distribution.
A Bulk Mineral Analysis (BMA) wasconducted using QEMSCAN technology on a single sample from the mediumgrade composite indicating approximately 2% sulphide minerals (1.14%arsenopyrite, 0.69% pyrite and 0.1% sphalerite). The host rock wascomposed primarily of quartz (57.0%), muscovite (22.2%) and feldspars(15.1%).
Bond Ball Mill Work Index Test was conducted on the Medium Grade sample and returned a Work Index of 17.2 kw-hr/tonne.
Metallurgical Testwork
Asingle rougher flotation test was completed at the bench scale using2kg charges from each of the three composites. Gold recoveries ofbetween 97.6% and 98.7% in rougher concentrates containing 7-8% of thefeed mass were recorded from the three samples at a primary grind sizeof 150 microns. Concentrates from the low and medium grade compositesassayed 11.6g/t and 28.4g/t gold respectively and would probablyrequire upgrading before sale. In addition, silver and arsenic bothreported to the rougher concentrates. The levels of arsenic may affectconcentrate quality and further testwork is required to determine ifflotation would be a suitable method for processing the JJ Main ore.
Gravityconcentration and cyanidation tests were conducted on 4kg samples fromeach of the three composites. A Knelson concentrate was produced andupgraded by panning. Knelson and pan tails were then combined andleached with cyanide. Gravity recoveries of 74% and 74.4% were returnedfrom the medium and high grade samples with the low grade compositereturning 39.5%. Total gold recoveries from gravity and leached tailswere 85.1% from low grade, 97.7% from medium grade and 99% from the high grade composite.
Bottleroll tests returned 63.4%, 96.0% and 98.6% recoveries over 48 hoursfrom the low, medium and high-grade composites, respectively.
Compositesamples used in this study were derived from coarse reject materialreturned from previously analysed HQ diamond core intervals. Samplescomprising the three composites were labeled and bagged under thesupervision of Astral's Project Geologist Dale Brittliffe, P.Geo., aQualified Person as defined in National Instrument 43-101. Samples weresubmitted to G & T Metallurgical Services Ltd at 2957 Bowers Place,Kamloops, B.C., Canada. Testwork was conducted and reviewed by G &T's professionally accredited metallurgical engineers andgeoscientists. The resulting report entitled "Metallurgical Assessment of the Jumping Josephine Deposit, Astral Mining Corporation KM2397" is posted on Astral's website at this link.
Astralhas earned a 60% interest in the JJ Project from Kootenay Gold Inc. andhas an option to earn the remaining 40% (see December 16th 2009 newsrelease).
Astral Mining Corporation is a Canadiancompany engaged in the exploration and development of precious metalproperties in North America. By focusing on exploration inmining-friendly districts, the Company minimizes the political andsocial risks encountered in many other parts of the world. With a newgold discovery at the Company's Jumping Josephine Gold Project inSouthern British Columbia and an experienced technical team andseasoned management, Astral is poised to leverage this expertise intoearly exploration success. Further details on Astral Mining Corporationand its high-quality portfolio of exploration projects can be found at www.astralmining.com.
ON BEHALF OF THE BOARD
Mr. Manfred Kurschner, President & CEO
Astral Mining Corporation