Corvus Gold Achieves High Gold Recoveries in Large Diameter Column Tests at North Bullfrog Project, Nevada
VANCOUVER, BRITISH COLUMBIA -- (Marketwire) -- 01/17/12 -- Corvus Gold Inc. (TSX: KOR)(OTCQX: CORVF) ('Corvus' or the 'Company') announces the results of its initial large diameter column leach testing of oxide resource materials from its 100% controlled North Bullfrog Project near Beatty, Nevada. The leach columns, which were testing coarse crush material (2 inch minus) from the Sierra Blanca and Jolly Jane areas (representing over 80% of the existing oxide resource), returned encouraging results. Average gold recovery for large diameter column tests for the Sierra Blanca area was 70% and 64% for the Jolly Jane area, which support an overall Run of Mine recovery plan (Table 1). The Company's concept of using Run of Mine material for heap leaching of gold could significantly lower capital and operating costs at the project. A preliminary economic assessment (PEA) is expected to be completed next month, which outline more specific project economics.
Jeff Pontius, CEO of Corvus, stated: 'These initial large diameter column test results are confirming the potential at North Bullfrog for a low unit cost, heap leach operation. These encouraging recovery results coupled with a highly favourable, low strip, surface mining geometry and nearby infrastructure greatly enhance the project's development potential. Corvus is encouraged by these results and will aggressively advance the North Bullfrog project to assess its potential to transform the Company into a future gold producer.'
Table 1
Initial Column Leach Test Results, North Bullfrog Project
Bulk Samples of Oxide Materials from the Sierra Blanca and Jolly Jane
Resource Areas
Leach Calc. Gold Rec.
/Rinse Gold Gold Tail Head (% Calc.
Test Time Extracted Assay Grade Head
No.(i) Feed Size (days) (g/t) (ii)(g/t) (g/t) Grade)
---------------------------------------------------------------------------
SB P-1 80%-50mm 117 0.204 0.0860 0.290 70.3
SB P-2 80%-50mm 117 0.200 0.0860 0.286 69.9
JJ P-3 80%-50mm 117 0.208 0.120 0.328 63.4
JJ P-4 80%-50mm 117 0.217 0.122 0.339 64.0
(i) SB - Sierra Blanca resource area; JJ - Jolly Jane resource area
(ii) - direct assay of total tail; tail assays by screen size are pending
Oxide Resource Testing
The results reported are from 12 inch diameter column leach tests, with 80% of the particles less than 50mm. The test samples were developed from bulk sampling of outcrops and existing mining excavations in the oxide portions of the Sierra Blanca and Jolly Jane resource areas. Sierra Blanca accounts for 60% of the Indicated and Inferred oxide resource, with Jolly Jane accounting for an additional 24% of the Indicated and Inferred oxide resource, as reported in the Company's NI 43-101 Technical Report dated November 7, 2011. The tests achieved 60-69% gold recovery in the first 90 days of cyanide leaching, and leaching was stopped after 117 days, an active leach time typical in heap leach mining operations. McClelland Laboratories, Inc. of Reno, Nevada, constructed the test columns from bulk samples collected at North Bullfrog by Corvus and conducted the leaching tests, whose results are listed in Table 1.
The column leach testing has focused on two of several targets in the North Bullfrog District, all of which remain open with potential to grow significantly (to view Figure 1 click on: http://media3.marketwire.com/docs/kor.pdf). Earlier cyanide bottle roll testing of oxide material, reported in NR11-20 (October 3, 2011) from the other resource areas (Connection and Mayflower), indicated similar metallurgical recovery. Ongoing metallurgical test work is focusing on confirmation of the Table 1 column leach data (at 80% -50 mm particle size) by conducting column tests on 80% - 12.5 mm material.
In addition to the column leaching tests, further bottle roll testing of North Bullfrog oxide resource materials has been conducted for confirmation of earlier metallurgical testing and to develop the basis to evaluate leach recovery versus particle size. Those cyanide bottle roll tests were performed for particle sizes of -1.7 mm and -0.075 mm, and are listed in Table 2. The tests focus on oxide and mixed oxide/sulphide materials from the Sierra Blanca resource area (Savage Valley area is a subset of Sierra Blanca) and the Jolly Jane resource area. Additional metallurgical testing will be an integral part of the next phase of drilling at North Bullfrog to further confirm and enhance the recovery model.
Table 2
Summary of Phase II - 72 Hour Cyanide Bottle Roll Recovery Tests for North
Bullfrog Project
Calc Head
Grade Au Total Au
Test ID Target Area (g/t) Oxidation Feed Size Recovery
---------------------------------------------------------------------------
SB Bulk 1a Sierra Blanca 0.27 Oxide 80%-1.7mm 88.20%
SB Bulk 1b Sierra Blanca 0.27 Oxide 80%-1.7mm 82.10%
SB Bulk 1c Sierra Blanca 0.27 Oxide 80%-0.075mm 85.90%
NBMC-4 Sierra Blanca 0.46 Oxide 80%-1.7mm 88.10%
NBMC-4 Sierra Blanca 0.46 Oxide 80%-0.075mm 88.20%
NBMC-5 Sierra Blanca 0.36 Oxide 70%-1.7mm 83.80%
NBMC-5 Sierra Blanca 0.36 Oxide 80%-0.075mm 92.10%
NBMC-6 Sierra Blanca 0.19 Oxide 79%-1.7mm 52.60%
NBMC-6 Sierra Blanca 0.19 Oxide 80%-0.075mm 86.70%
NBMC-7 Sierra Blanca 0.33 Mixed Ox/Sulf 20%-1.7mm 68.00%
NBMC-7 Sierra Blanca 0.33 Mixed Ox/Sulf 80%-0.075mm 71.00%
NBMC-8 Sierra Blanca 0.37 Mixed Ox/Sulf 85%-1.7mm 71.10%
NBMC-8 Sierra Blanca 0.37 Mixed Ox/Sulf 80%-0.075mm 75.10%
NBMC-9 Savage Valley 0.56 Oxide 49%-1.7mm 63.80%
NBMC-9 Savage Valley 0.56 Oxide 80%-0.075mm 91.00%
NBMC-10 Savage Valley 0.39 Oxide 70%-1.7mm 87.10%
NBMC-10 Savage Valley 0.39 Oxide 80%-0.075mm 85.50%
NBMC-11 Savage Valley 0.17 Oxide 64%-1.7mm 76.50%
NBMC-11 Savage Valley 0.17 Oxide 80%-0.075mm 89.80%
NBMC-12 Savage Valley 0.40 Mixed Ox/Sulf 74%-1.7mm 73.50%
NBMC-12 Savage Valley 0.40 Mixed Ox/Sulf 80%-0.075mm 72.30%
NBMC-13 Savage Valley 0.20 Mixed Ox/Sulf 46%-1.7mm 66.70%
NBMC-13 Savage Valley 0.20 Mixed Ox/Sulf 80%-0.075mm 81.90%
JJ Bulk 1a Jolly Jane 0.33 Oxide 80%-1.7mm 72.70%
JJ Bulk 1b Jolly Jane 0.33 Oxide 80%-1.7mm 76.60%
JJ Bulk 1c Jolly Jane 0.33 Oxide 80%-0.075mm 80.00%
NBMC-1 Jolly Jane 0.35 Oxide 79%-1.7mm 64.30%
NBMC-1 Jolly Jane 0.35 Oxide 80%-0.075mm 80.00%
NBMC-2 Jolly Jane 0.18 Oxide 65%-1.7mm 66.70%
NBMC-2 Jolly Jane 0.18 Oxide 80%-0.075mm 76.80%
NBMC-3 Jolly Jane 0.38 Oxide 65%-1.7mm 67.50%
NBMC-3 Jolly Jane 0.38 Oxide 80%-0.075mm 79.50%
The total recovery indicates the total amount of gold that was dissolved in
72 hours.
About the North Bullfrog Project, Nevada
Corvus controls 100% of its North Bullfrog Project, which covers approximately 24 square kilometres in southern Nevada just north of the historic Bullfrog gold mine formerly operated by Barrick. The property package is made up of a number of private mineral leases of patented federal mining claims and 161 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 NI 43-101 compliant estimated Indicated Resource of 15 Mt at an average grade of 0.37 g/t gold for 182,000 ounces of gold and an Inferred Resource of 156 Mt at 0.28 g/t gold for 1,410,000 ounces of gold (both at a 0.2 g/t cutoff), with appreciable silver credits. 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 Yellowjacket 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 form 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.
Mr. Gary Giroux, M.Sc., P. Eng (B.C.), a consulting geological engineer employed by Giroux Consultants Ltd., has acted as the Qualified Person, as defined in NI 43-101, for the Giroux Consultants Ltd. mineral resource estimate. He has over 30 years of experience in all stages of mineral exploration, development and production. Mr. Giroux specializes in computer applications in ore reserve estimation, and has consulted both nationally and internationally in this field. He has authored many papers on geostatistics and ore reserve estimation and has practiced as a Geological Engineer since 1970 and provided geostatistical services to the industry since 1976. Both Mr. Giroux and Giroux Consultants Ltd. are independent of the Company under NI 43-101.
Mr. William J. Pennstrom, Jr., a consulting process engineer and President of Pennstrom Consulting Inc. has acted as the Qualified Person, as defined by NI 43-101, for evaluation 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 ten (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, and 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.
Jeffrey A. Pontius, Chairman and Chief Executive Officer
Cautionary Note Regarding Forward-Looking Statements
This press release contains forward-looking statements and forward-looking information (collectively, 'forward-looking statements') within the meaning of applicable Canadian and US securities legislation. All statements, other than statements of historical fact, included herein including, without limitation, statements regarding the anticipated content, commencement and cost of exploration programs, anticipated exploration and metallurgical test program results, the discovery and delineation of mineral deposits/resources/reserves, the potential for any mining or production at North Bullfrog, the potential for the identification of multiple deposits at North Bullfrog, the potential for a low-cost run-of-mine heap leach operation at North Bullfrog, the potential for there to be a low strip ratio in connection with any mine at North Bullfrog, the potential for the existence or location of additional high-grade veins, the potential to use Run of Mine material for heap leaching of gold, the potential for the use of Run of Mine material to significantly lower capital and operating costs at the project; the proposed completion of a PEA for the North Bullfrog project, the potential for additional resources to be located between certain of the existing deposits, the potential for the Company to secure or receive any royalties in the future, business and financing plans and business trends, are forward-looking statements.
Information concerning mineral resource estimates and the preliminary economic analysis thereof also may be deemed to be forward-looking statements in that it reflects a prediction of the mineralization that would be encountered, and the results of mining it, if a mineral deposit were developed and mined. Although the Company believes that such statements are reasonable, it can give no assurance that such expectations will prove to be correct. Forward-looking statements are typically identified by words such as: believe, expect, anticipate, intend, estimate, postulate and similar expressions, or are those, which, by their nature, refer to future events. The Company cautions investors that any forward-looking statements by the Company are not guarantees of future results or performance, and that actual results may differ materially from those in forward looking statements as a result of various factors, including, but not limited to, variations in the nature, quality and quantity of any mineral deposits that may be located, variations in the market price of any mineral products the Company may produce or plan to produce, the Company's inability to obtain any necessary permits, consents or authorizations required for its activities, the Company's inability to produce minerals from its properties successfully or profitably, to continue its projected growth, to raise the necessary capital or to be fully able to implement its business strategies, and other risks and uncertainties disclosed in the Company's latest interim Management Discussion and Analysis and filed with certain securities commissions in Canada. All of the Company's Canadian public disclosure filings may be accessed via www.sedar.com and readers are urged to review these materials, including the technical reports filed with respect to the Company's mineral properties.
Cautionary Note Regarding References to Resources and Reserves
National Instrument 43 101 - Standards of Disclosure for Mineral Projects ('NI 43-101') is a rule developed by the Canadian Securities Administrators which establishes standards for all public disclosure an issuer makes of scientific and technical information concerning mineral projects. Unless otherwise indicated, all resource estimates contained in or incorporated by reference in this press release have been prepared in accordance with NI 43-101 and the guidelines set out in the Canadian Institute of Mining, Metallurgy and Petroleum (the 'CIM') Standards on Mineral Resource and Mineral Reserves, adopted by the CIM Council on November 14, 2004 (the 'CIM Standards') as they may be amended from time to time by the CIM.
United States shareholders are cautioned that the requirements and terminology of NI 43-101 and the CIM Standards differ significantly from the requirements and terminology of the SEC set forth in the SEC's Industry Guide 7 ('SEC Industry Guide 7'). Accordingly, the Company's disclosures regarding mineralization may not be comparable to similar information disclosed by companies subject to SEC Industry Guide 7. Without limiting the foregoing, while the terms 'mineral resources', 'inferred mineral resources', 'indicated mineral resources' and 'measured mineral resources' are recognized and required by NI 43-101 and the CIM Standards, they are not recognized by the SEC and are not permitted to be used in documents filed with the SEC by companies subject to SEC Industry Guide 7. Mineral resources which are not mineral reserves do not have demonstrated economic viability, and US investors are cautioned not to assume that all or any part of a mineral resource will ever be converted into reserves. Further, inferred resources have a great amount of uncertainty as to their existence and as to whether they can be mined legally or economically. It cannot be assumed that all or any part of the inferred resources will ever be upgraded to a higher resource category. Under Canadian rules, estimates of inferred mineral resources may not form the basis of a feasibility study or prefeasibility study, except in rare cases. The SEC normally only permits issuers to report mineralization that does not constitute SEC Industry Guide 7 compliant 'reserves' as in-place tonnage and grade without reference to unit amounts. The term 'contained ounces' is not permitted under the rules of SEC Industry Guide 7. In addition, the NI 43-101 and CIM Standards definition of a 'reserve' differs from the definition in SEC Industry Guide 7. In SEC Industry Guide 7, a mineral reserve is defined as a part of a mineral deposit which could be economically and legally extracted or produced at the time the mineral reserve determination is made, and a 'final' or 'bankable' feasibility study is required to report reserves, the three-year historical price is used in any reserve or cash flow analysis of designated reserves and the primary environmental analysis or report must be filed with the appropriate governmental authority.
Caution Regarding Adjacent or Similar Mineral Properties
This news release contains information with respect to adjacent or similar mineral properties in respect of which the Company has no interest or rights to explore or mine. The Company advises US investors that the mining guidelines of the US Securities and Exchange Commission (the 'SEC') set forth in the SEC's Industry Guide 7 ('SEC Industry Guide 7') strictly prohibit information of this type in documents filed with the SEC. Readers are cautioned that the Company has no interest in or right to acquire any interest in any such properties, and that mineral deposits on adjacent or similar properties are not indicative of mineral deposits on the Company's properties.
This press release is not, and is not to be construed in any way as, an offer to buy or sell securities in the United States.
Contacts:
Corvus Gold Inc.
Ryan Ko
Investor Relations
604-638-3246 or Toll Free: 1-888-770-7488
604-408-7499 (FAX)
info@corvusgold.com
www.corvusgold.com
