Argentex Announces Positive Metallurgical Results at Pinguino Silver-Gold Project
VANCOUVER, BRITISH COLUMBIA -- (Marketwire) -- 02/21/13 -- Argentex Mining Corporation (TSX VENTURE: ATX)(OTCQB: AGXMF) ("Argentex" or the "Company") is pleased to announce the results of preliminary metallurgical testing at the Company's 100%-owned Pinguino Silver-Gold Project, located in Santa Cruz province, Argentina.
Highlights include:
-- Preliminary heap leach column test work on the oxide samples indicated
silver recoveries up to 81% and gold recoveries up to 69% with leaching
times of up to 45 days. Silver and gold were still leaching when the
tests were terminated, suggesting the potential for recoveries to
increase with longer leaching periods.
-- Bottle roll test work on oxide samples indicated recoveries up to 95%
for silver and up to 94% for gold.
-- Flotation of Marta Este and Marta Centro sulphide vein materials
resulted in good deportment of the lead and zinc to the respective
concentrates at potentially saleable grades.
"The results of our first round of metallurgical testing at Pinguino are promising. We anticipate that future process optimization studies will improve recovery efficiencies and cost reduction benefits," commented Mike Brown, President and CEO of Argentex. "We view these results as another milestone toward the continued advancement of the Pinguino project."
Pinguino Metallurgical Summary
Metallurgical test work was undertaken on five veins of oxide mineralization and two veins of sulphide mineralization. Samples were selected based on assay and other information. Flotation and cyanidation testing was completed by ALS-G&T at Kamloops, British Columbia, Canada on drill hole samples, with the heap leach column testing completed by ALS-AMMTEC in Australia on oxide samples from surface trenches.
Preliminary Flotation and Cyanidation Testing
The flotation test results showed non-optimized silver, lead and zinc metal recoveries from Marta Este and Centro sulphides as shown in the table below. Based on the preliminary nature of the test work there appears to be scope for further optimization.
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Grade Recovery
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Pb Zn Au Ag Pb Zn Au Ag
Vein/Material Stream % % g/t g/t % % % %
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Feed 2.54% 2.06% 0.45 203 100.0% 100.0% 100.0% 100.0%
Marta Este Pb Conc 67.1% 7.9% 0.19 3,010 90.5% 7.9% 19.4% 50.8%
Zn Conc 1.7% 53.5% 0.24 693 2.0% 78.1% 1.6% 10.3%
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Feed 1.73% 5.65% 0.38 53 100.0% 100.0% 100.0% 100.0%
Marta Centro Pb Conc 61.20% 5.18% 1.27 1090 86.8% 2.2% 8.2% 50.2%
Zn Conc 0.57% 55.80% 0.06 124 2.7% 79.7% 1.2% 18.8%
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These results were achieved at primary grinds of 80% passing 70 to 75 microns and Pb and Zn regrinds of 10 and 15 microns, respectively. It is expected that with further work these variables could be optimized to provide both improved recoveries and lower grinding requirements. In addition, closing the circuit in a locked cycle test generally improves overall recovery. Cyanidation test work completed on finely ground zinc rougher flotation tails showed that silver recovery from Marta Este and Marta Centro was 52% and 49%, respectively. Tailings cyanidation gold recovery was low at 26% and 11%, respectively.
Preliminary Leach Testing
Preliminary heap leach column test work on the oxide samples was encouraging. Marta Norte and Tranquilo samples were crushed to minus half inch and leached in seven-inch columns. Silver recoveries for the two veins were 70% after 30 days and 81% after 45 days, respectively. Gold recoveries returned were 63% and 69%, respectively. Both silver and gold were still leaching when the tests were terminated, suggesting the recoveries may increase with longer leaching periods.
Bottle roll test work by ALS on oxide samples ground to minus 75 micron indicated 48-hour recoveries ranging from 34% to 95% for silver and 76% to 94% for gold. G&T completed bottle roll testing on drill core oxide composites from five of the veins. These indicated good recoveries from 4 of the veins for both precious metals.
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Au Ag NaCN CaO
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Feed Res. 48 Hr Feed Res. 48 Hr
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g/t g/t Ext. g/t g/t Ext. kg/t kg/t
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Vein/Material % %
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Marta Este - Oxide(i) 4.24 0.51 87.98% 1,588 1,110 30% 1.92 0.88
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Marta Centro - Oxide 2.90 0.19 93.44% 140 26 81.59% 0.92 1.10
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Marta Norte - Oxide 0.27 0.02 92.58% 624 17 97.21% 1.64 1.06
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IVN e IVO - Oxide 2.60 0.48 81.57% 23 10 55.30% 0.96 1.70
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Tranquilo - Oxide 0.09 0.02 78.39% 64 10 85.11% 0.96 1.70
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(i) As a result of the low silver recovery from the high-grade Marta Este
Oxide composite, it was later retested under more aggressive leach
conditions and this resulted in gold and silver recoveries of 96% and
98%, respectively. Mineralogical work is currently underway to identify
the high grade silver mineral in this material and future testing will
involve optimization of recoveries and reagent requirements related to
its presence.
Results from similar bottle roll tests on sulphide zone samples were generally poor. Further work on representative composites from sulphide veins is recommended to fully evaluate the potential for leaching sulphide material. The Company intends to conduct ongoing metallurgical test work in order to evaluate recoveries and costs of various process alternatives.
The Company continues to review the metallurgical results to date in an effort to determine next steps for future studies intended to advance the Pinguino asset. Please visit the Company's website at www.argentexmining.com for full disclosure on the metallurgical studies.
About Pinguino
Argentex's 10,000-hectare advanced silver and gold exploration Pinguino project is located in Argentina's Patagonia region, within the Deseado Massif of Santa Cruz province. The Deseado Massif is an active region of mining with four precious metal mines currently in production, and includes multiple active advanced and early stage exploration projects.
The Pinguino system has grown to 70+ individual veins, with a combined strike length approaching approx. 113 line-kilometers. The Pinguino project is unique within the Deseado Massif region of Santa Cruz province in that it contains two different and spatially distinct types of mineralization, one precious metal and the other sulphide-rich polymetallic. The Company continues to evaluate the geological model of sulphide-enriched potentially mineralized intrusives at depth, forming the probable source for the polymetallic veins exposed on surface.
Pinguino is easily accessible, situated approximately 400 meters above sea level in low-relief topography. An existing system of all-weather roads provides year-round access to the property.
Technical discussions related to the metallurgical studies has been reviewed and approved by Mr. Robert Tucker, P.Eng. Mr. Tucker supervised and interpreted results of the metallurgical test work and is a "Qualified Person" as defined under the terms of National Instrument 43-101. Metallurgical testing was carried out by ALS-G&T Metallurgical Labs in Kamloops, BC and ALS-Ammtec Metallurgy in Perth Australia.
All other technical content of this press release has been reviewed and approved by Mr. J. David Williams, P.Eng., an independent "Qualified Person" as defined by NI 43-101.
About Argentex
Argentex Mining Corporation is an exploration company focused on advancing its Pinguino silver-gold project in Santa Cruz, Argentina. In total, Argentex owns 100% of the mineral rights to more than 35 properties located within approximately 307,981 acres (124,636 hectares) of highly prospective land located in the Santa Cruz and Rio Negro provinces.
Shares of Argentex common stock trade under the symbol ATX on the TSX Venture Exchange and under the symbol AGXMF on the OTCQB. Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.
On behalf of Argentex Mining Corporation:
Michael Brown, President and CEO
Statements in this news release that are not historical facts are forward-looking statements that are subject to risks and uncertainties. Words such as "expects", "intends", "plans", "may", "could", "should", "anticipates", "likely", "believes" and words of similar import also identify forward-looking statements. Forward-looking statements in this news release include the Company's belief, based on the fact that silver and gold were still leaching when the tests were terminated, that recoveries may increase with longer leaching period, its anticipation that future process optimization studies will improve recovery efficiencies and cost reduction benefits; Its expectation that with further work, the variables in the flotation testing could be optimized with respect to both improved recoveries and lower grinding requirements ;its understanding that, because both silver and gold were still leaching when the tests were terminated, recoveries may increase with longer leaching periods; its anticipation that mineralogical work currently underway to identify the high grade silver mineral in this material and future testing will involve optimization of recoveries and reagent requirements related to its presence; that future work will use the new resource estimate to determine representative samples and that this will allow metallurgical test work to be done in a manner that allows various process options to be evaluated in terms of recoveries and costs. Actual results may differ materially from those currently anticipated due to a number of factors beyond the Company's control. These risks and uncertainties include, among other things, the availability of the Company's consultants and risks that are inherent in Argentex's operations including the risks that the Company may not find any minerals in commercially feasible quantity or raise enough money to fund its exploration plans. These and other risks are described in the Company's Annual Information Form and other public disclosure documents filed on the SEDAR website maintained by the Canadian Securities Administrators and the EDGAR website maintained by the Securities and Exchange Commission.
Contacts:
Argentex Mining Corporation
Peter A. Ball
EVP Corporate Development
604-568-2496 (ext. 103) or 1-888-227-5285 (ext. 103)
604-568-1540 (FAX)
peter@argentexmining.com
www.argentexmining.com