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Operations: Copper-gold-silver-mine in Bolivia, Gold/copper mine/Mill in Spain and its developing copper project in Michigan
Message: Detailed Operational Study/Audited Resource Estimate/Don Mario Upper Zone
| February 9, 2009 | |
| Orvana Announces Progress on a Detailed Operational Study and Updated Audited Resource Estimate for the Don Mario Upper Mineralized Zone | |
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TORONTO, ONTARIO--(Marketwire - Feb. 9, 2009) - Orvana Minerals Corp. (TSX:ORV) is pleased to announce progress of a detailed operational study prepared by Kappes, Cassiday & Associates (KCA) of Reno, Nevada on the Don Mario Upper Mineralized Zone (UMZ) polymetallic deposit located in eastern Bolivia. In addition, AMEC (Peru) S.A. (AMEC) audited a National Instrument (NI) 43-101 - compliant mineral resources estimate completed by Orvana for the UMZ. The mineral resource estimates audited by AMEC are different from those used for the operational study, which demonstrated favourable economics, but with a revised flow sheet. Orvana will expeditiously commission a revised mine plan and economic model based on the revised flow sheet and updated mineral resources. The UMZ copper-gold deposit comprises a small hill devoid of vegetation and overlies the Lower Mineralized Zone (LMZ), a gold-bearing shear zone currently being mined underground by Orvana. The deposit lies in the hanging wall of the LMZ shear zone and is believed to have been discovered and worked by Jesuit settlers in the 18th century. The UMZ has been subject to various sampling and drill campaigns in the past. A calc-silicate rock hosts copper, gold, silver, and zinc in four defined mineralized zones, from surface downward: 1) Porous, 2) Oxide, 3) Transition, and 4) Sulphide. The uppermost Porous Zone is characterized by vuggy cavities that are locally occupied by masses of amorphous zinc carbonate and hydroxides. Below that, in the Oxide Zone, malachite is the principal constituent with lesser amounts of chrysocolla, azurite, native copper, cuprite, and silver sulfosalts. The Transition Zone is characterized by bornite, sphalerite, galena, and pyrite, commonly coated by chalcocite. The lowermost Sulphide Zone is characterized by chalcopyrite and bornite. The tonnes and grade of each zone is tabulated below. A pre-feasibility study and previous estimate of mineral reserves completed in 2006 for the UMZ Project have been superseded by the completion of a diamond drill program whose main purpose was to collect samples for additional metallurgical testing, a detailed operational design study by KCA, and an updated mineral resource estimate audited by AMEC. On the basis of metallurgical test work and more detailed cost estimation and economic analysis, KCA has determined that a simplified process flow sheet that contemplates flotation treatment instead of a combined heap-leach and flotation operation has acceptable economics. The current concept for the UMZ project involves a flotation plant with a mill throughput of 1,875 tonnes per day over a nine-year mine life. During the first five years, Oxide and Porous Zone mineralization would be stockpiled and the Transition Zone and Sulphide Zone ore would be treated to recover copper, gold, and silver. During the remaining years, the stockpiled oxide material would be treated to recover gold and silver. All the material would be mined by open pit. In September 2008, Orvana contracted AMEC to audit the updated mineral resource estimate completed by Orvana that incorporated the 2007 diamond drilling. The results of the audited mineral resource estimates for the UMZ are as follows: Mineral Resource Estimate Effective 19 December 2008
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Zone Classification tonnes Cu Au Ag AuEq,
(kt) (%) (g/t) (g/t) (g/t)
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Porous Indicated 539 1.99 1.39 43.4 7.30
Inferred 45 2.54 1.44 29.3 8.52
Oxide Indicated 1,788 1.74 1.63 50.7 7.03
Inferred 173 1.74 1.43 43.8 6.72
Transition Measured 913 1.32 1.45 51.7 5.78
Indicated 1,041 1.23 1.33 46.6 5.35
Inferred 82 1.08 0.95 45.1 4.56
Sulphide Measured 774 1.19 1.18 32.3 4.82
Indicated 1,148 1.11 1.05 33.5 4.53
Inferred 17 0.78 0.95 18.20 3.29
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TOTAL M & I 6,203 1.43 1.37 44.0 5.85
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Note: Au equivalent is calculated as AuEq. equals Au (g/t)+Ag
(g/t)x(US$11/oz)/(600 US$/oz)+Cu (%)/(100x2204.64 lb/t x US$2.25/lb/(US$
600/oz/31.103 g/oz)). Mineral Resources are contained by a pit shell from
a 2006 study by NCL (Kolin and Bentzen, 2006) and above a cut off of 1 g/t
Au Eq and grades have not been adjusted for metallurgical recovery.
Measured and indicated mineral resources are denoted M&I. Mineral Resources
for the Don Mario UMZ Project have been verified by QP Christopher Wright,
P.Geo.
Carlos Mirabal, President and Chief Executive Officer of Orvana, said: "The UMZ offers a great opportunity to utilize the infrastructure at Don Mario after the expected end of gold production from Las Tojas during the second half of fiscal 2010 (see February 9, 2009 press release). Based on our operating experience in Bolivia and with a very experienced team at the mine site, we believe that we can substantially reduce the preproduction capital costs of over $30M contemplated in the study by Kappes, Cassiday & Associates, thereby increasing an already acceptable IRR. It does not appear that the updated resource estimate will significantly affect the economics of the project as determined by the operational study, but we will quantify that with an updated mine plan and economic model. Orvana is seeking satisfactory financing and, subject to obtaining it, expects to proceed with the project. Once financing is obtained, we believe that production can start within 12 months." The detailed operational study of the UMZ presented herein was completed by or under the supervision of Dan Kappes, an independent Qualified Person for the purposes of the Canadian Securities Administrators' NI 43-101. The KCA report will be available on the Company's website, www.orvana.com, even though the parameters therein will be modified using the updated mineral resource estimate. The current UMZ resource estimates presented herein were reviewed by or under the supervision of AMEC (Peru) S.A. Senior Geologist Christopher Wright, P.Geo. (APGO, 901), an independent Qualified Person for the purposes of NI 43-101. The NI 43-101 compliant Technical Report on the Don Mario Property including the UMZ Mineral Resources will be available within 45 days on the Company's website at www.orvana.com and on SEDAR at www.sedar.com. About Orvana Orvana Minerals Corp. is a Canadian mining and exploration company based in Toronto, Canada, involved in the evaluation, development and mining of precious and base metal deposits in the Americas. The Company owns and operates the Don Mario Mine in eastern Bolivia. Orvana's long-term goal is to become a low cost, long-life, multi-mine gold and base metals producer in the Americas. Orvana's shares have been listed on the Toronto Stock Exchange since 1992 under the trading symbol ORV. Further information on Orvana may be found on the Company's website at www.orvana.com and on SEDAR at www.sedar.com. |
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