Corvus Gold Receives Encouraging Gold-Silver Leach Recovery Results from Yellow Jacket High-Grade Zone
Vancouver, B.C……..Corvus Gold Inc. (“Corvus” or the “Company”) – (TSX: KOR, OTCQX: CORVF) announces the results of a series of cyanide bottle roll tests on sample composites from the Yellow Jacket high-grade gold-silver zone, North Bullfrog, Nevada (Table 1). The results from 22 composites throughout the currently defined high-grade area averaged recoveries of 86% for gold and 77% for silver with very low cyanide and lime consumption for material averaging 3.0 g/t gold and 29.0 g/t silver (Table 2). The drill results to date from the Yellow Jacket Zone have yet to be incorporated into the current resource estimate and preliminary economic assessment (NR13-13, June 4, 2013) and include: NB 12-138, 72.4m of 1.74 g/t gold & 98.7 g/t silver, including 4.3m of 20.0 g/t gold & 1,519 g/t silver (see NR12-20). The Company is planning to complete an updated resource estimate and preliminary economic assessment in late 2013 incorporating the results from the current drill program, new metallurgical data and past results from the Yellow Jacket zone.
The bottle roll tests were run for 96 hours and displayed characteristics of continuing metal recovery suggesting that ultimate recoveries had not been reached. Subsequent longer term tests on coarser fractions are in progress. Initial data indicates mineralization starts at 40m depth and extends to at least 130m, which suggests that this high-grade zone might be amenable to standard low cost open pit mining and heap leach gold-silver recovery, and could form the nucleus of a large starter pit phase that has yet to be included in the mining project model.
The silver recoveries from the Yellow Jacket zone are significantly higher than the 8% average recovery found at the other zones of the North Bullfrog project as described in the Company’s latest preliminary economic study (NR13-13, June 4, 2013). The new recovery data is relatively uniform across oxidation, veining and wall rock types, suggesting that the observed hotter system temperatures have eliminated the effect of sulfide on recovery. This is encouraging, as recent exploration work is defining a much hotter system to the north.
The Yellow Jacket Zone is a large emerging high-grade target discovered in 2012 and is the focus of the Company’s 2013 diamond drilling program. Current work has been directed at extending the Yellow Jacket system to the north by approximately 1 kilometre. The currently defined 700 metre long zone at Yellow Jacket is approximately 100 metres wide, has been tested to a depth of 130 metres and remains open in all directions. To date, four step-out holes covering a 100 metre northern extension have been completed, and these have continued to intersect favourable veining and alteration (assays pending). In addition, ongoing reverse circulation drilling half a kilometre north of the currently defined Sierra Blanca deposit is focused on expanding higher grade mineralization discovered in the 2012 scout drilling program.
Table 1: Summary by rock type of new Yellow Jacket Zone bottle roll tests
|Mineralization Type Summary||Avg. Gold Recovery (%)||Avg. Gold Grade (g/mt)||Avg. Silver Recovery (%)||Avg. Silver Grade (g/mt)|
|UNOX Vein Bx||75.1%||4.13||70%||35.05|
|Mixed Vein BX||89.0%||3.46||85%||46.81|
Carl Brechtel, COO of Corvus, stated: “The new Yellow Jacket heap leach results are very encouraging and suggest the potential to add a large high-grade starter pit component to our existing North Bullfrog deposit. The effect of the higher grade, early mining phase could be significant, as it will benefit from the low open pit mining and heap leach production costs. These results continue to enhance the North Bullfrog project and support the significant potential for developing Nevada’s next new gold mine.”
Results for 22 Yellow Jacket Zone cyanide bottle roll tests (96 hour on 80% passing 200 mesh material)
|Mineralization Type||Recovery,||Head Grade||Recovery||Head Grade||kg/mt ore|
|NaCN Cons.||Lime Added|
|UNOX Vein Bx||83.8||6.54||67.8||43||0.09||1.1|
|UNOX Vein Bx||82.4||5.97||65.1||42||0.14||1.2|
|UNOX Vein Bx||73.4||3.23||61.0||44||0.12||1.6|
|UNOX Vein Bx||76.9||3.33||73.0||46||0.21||1.6|
|UNOX Vein Bx||68.7||1.98||69.9||21||0.23||1.1|
|UNOX Vein Bx||73.6||1.97||76.4||20||0.13||1.0|
|UNOX Vein Bx||78.5||5.16||70.7||32||0.20||1.0|
|UNOX Vein Bx||78.7||4.83||72.8||33||0.21||0.9|
|Mixed Vein BX||84.1||8.18||80.1||43||0.11||1.1|
|Mixed Vein BX||87.2||8.11||79.2||43||0.17||1.1|
|Mixed Vein BX||91.8||0.85||88.2||50||0.12||1.1|
|Mixed Vein BX||92.4||0.79||85.7||54||0.13||1.1|
|Mixed Vein BX||94.8||3.63||89.7||40||0.22||1.1|
|Mixed Vein BX||92.8||3.46||89.1||40||0.15||1.1|
|Mixed Vein BX||86.9||1.37||83.6||52||0.26||1.1|
|Mixed Vein BX||82.3||1.30||83.5||53||0.34||1.1|
About the North Bullfrog Project, Nevada
Corvus controls 100% of its North Bullfrog Project, which covers approximately 70 square kilometres in southern Nevada just north of the historic Bullfrog gold mine formerly operated by Barrick Gold Corp. The property package is made up of a number of private mineral leases of patented federal mining claims and 758 federal unpatented mining claims. The project has excellent infrastructure, being adjacent to a major highway and power corridor.
The project currently includes numerous prospective gold targets with four (Mayflower, Sierra Blanca, Jolly Jane and Connection) containing an estimated Oxidized Indicated Resource of 36.7 Mt at an average grade of 0.26 g/t gold for 307,860 ounces of gold and an Oxidized Inferred Resource of 220.7 Mt at 0.18 g/t gold for 1,288,970 ounces of gold (both at a 0.1 g/t gold cutoff), with appreciable silver credits. Unoxidized Inferred mineral resources are 221.6 Mt at 0.19 g/t for 1,361,000 ounces of gold (at a 0.1 g/t gold cutoff).
Mineralization occurs in two primary forms: (1) broad stratabound bulk-tonnage gold zones such as the Sierra Blanca and Jolly Jane systems; and (2) moderately thick zones of high-grade gold and silver mineralization hosted by structural zones with breccias and quartz-sulphide vein stockworks such as the Mayflower and Yellow Jacket targets. The Company is actively pursuing both types of mineralization.
A video of the North Bullfrog project showing location, infrastructure access, and 2010 winter drilling is available on the Company’s website at http://www.corvusgold.com/investors/video/.
Qualified Person and Quality Control/Quality Assurance
Jeffrey A. Pontius (CPG 11044), a qualified person as defined by National Instrument 43-101, has supervised the preparation of the scientific and technical information (other than the resource estimate) that forms the basis for this news release and has approved the disclosure herein. Mr. Pontius is not independent of Corvus, as he is the CEO and holds common shares and incentive stock options.
Carl E. Brechtel, PE, a qualified person as defined by National Instrument 43-101, is responsible for coordination of the testing contractors and integration of the resulting technical data into the engineering studies at North Bullfrog. He has prepared this news release and approves the disclosure herein. He has over 30 years of experience in the mining industry, is a registered professional engineer in the States of Colorado and Nevada, and is a Registered Member of SME. Mr. Brechtel is not independent of Corvus, as he is the COO and holds common shares and incentive stock options.
Mr. William J. Penstrom, Jr., a consulting process engineer and President of Pennstrom Consulting, Inc. has acted at the Qualified Person, as defined by NI 43-101, is responsible for recommending the metallurgical testing program, and for review and interpretation of the metallurgical testing data. He has over 30 years of experience in mineral process design and operation, and has been an independent process and metallurgical consultant for the mining industry for the last 10 years. He is a Registered Member of the Society of Mining, Metallurgy and Exploration (SME Member No. 2503900). Mr. Pennstrom and Pennstrom Consulting Inc. are both independent of the Company under NI 43-101.
The work program at North Bullfrog was designed and supervised by Russell Myers (CPG 11433), President of Corvus, a Qualified Person defined by NI 43-101, and by Mark Reischman, Corvus Nevada Exploration Manager, who are responsible for all aspects of the work, including the quality control/quality assurance program. On-site personnel at the project log and track all samples prior to sealing and shipping. Quality control is monitored by the insertion of blind certified standard reference materials and blanks into each sample shipment. All resource sample shipments are sealed and shipped to ALS Chemex in Reno, Nevada, for preparation and then on to ALS Chemex in Reno, Nevada, or Vancouver, B.C., for assaying. ALS Chemex’s quality system complies with the requirements for the International Standards ISO 9001:2000 and ISO 17025:1999. Analytical accuracy and precision are monitored by the analysis of reagent blanks, reference material and replicate samples. Finally, representative blind duplicate samples are forwarded to ALS Chemex and an ISO compliant third party laboratory for additional quality control. McClelland Laboratories Inc. prepared composites from duplicated RC sample splits collected during drilling. Bulk samples were sealed on site and delivered to McClelland Laboratories Inc. by ALS Chemex or Corvus personnel. All metallurgical testing reported here was conducted or managed by McClelland Laboratories Inc.
About Corvus Gold Inc.
Corvus Gold Inc. is a resource exploration company, focused in Alaska and Nevada, which controls a number of exploration projects representing a spectrum of early-stage to advanced gold projects. Corvus is committed to building shareholder value through new discoveries and leveraging those discoveries via partner funded exploration work into carried and or royalty interests that provide shareholders with exposure to gold production.
On behalf of
Corvus Gold Inc.
(signed) Jeffrey A. Pontius
Jeffrey A. Pontius,
Chief Executive Officer
Contact Information: Ryan Ko
Phone: 1-888-770-7488 (toll free) or (604) 638-3246 / Fax: (604) 408-7499