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April 1, 2008
AURIZON PROVIDES MINERAL RESERVES AND RESOURCES UPDATE
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Aurizon Mines Ltd. (TSX: ARZ; AMEX: AZK) reports mineral reserves and resources estimates as at December 31, 2007 for its Casa Berardi and Joanna projects, both located in north western Quebec, Canada.
- Upon achieving commercial production at Casa Berardi, Aurizon initiated the process of converting mineral resources to mineral reserves. The gain in mineral reserves from resource conversion has been offset by 2007 mine production, a reduction in projected mining recoveries and an increase in cut-off grade. Mineral reserves, using the three year trailing average gold price of US$581 per ounce, are estimated at 3.1 million tonnes averaging 9.3 grams of gold per tonne for 918,000 ounces, resulting in a gain of 21% in grade and a depletion of 251,000 ounces.
- As a result of the current gold prices being significantly higher than US$581 per ounce used to establish reserves, the 2008 mining plan includes the production of 77,000 tonnes averaging 4.3 grams of gold per tonne or 11,000 ounces, currently classified as mineral resources. These resources are located within Zones 113 and North West, close to existing development and underground infrastructure. As previously reported, the 2008 mining plan estimates gold production of 160,000 ounces of gold at an average grade of 8.6 grams of gold per tonne.
- Total measured and indicated mineral resource estimates result in a gain of 456,000 ounces in comparison with 2006, including increases of 136,000 ounces at Casa Berardi and 320,000 ounces at Joanna.
- Total inferred mineral resource estimates result in a gain of 465,000 ounces in comparison with 2006, including increases of 154,000 ounces at Casa Berardi and 311,000 ounces at Joanna.
- A new inferred mineral resource estimate for the newly discovered Zone 123-S, located one kilometre east of the West Mine area at Casa Berardi, resulted in inferred mineral resources of 714,000 tonnes averaging
9.4 grams of gold per tonne for 216,000 ounces.
"Aurizon's focus at Casa Berardi during 2007 was to achieve commercial production and gradually ramp up mine output", said David Hall, President and CEO. "Our significant operating cash flow will enable us to develop improved underground drilling access and undertake major drill programs to transfer mineral resources to mineral reserves. The increase in resources at our two projects bodes well for Aurizon's future growth." he added.
Mineral reserve and resource estimates have been completed in accordance with the Standards of Disclosure for Mineral Projects as defined by National Instrument 43-101.
Casa Berardi mine
The Casa Berardi mine is a vein type deposit located close to the contact between a sedimentary basin sequence and the volcanic basement. The deposit extends for a 5 kilometre strike length along the Casa Berardi Fault system. The mine produced 159,500 recovered ounces of gold in 2007, reaching the commercial production stage on May 1, 2007.
Scott Wilson Roscoe Postle ("Scott Wilson RPA") and Breton Banville and Associates ("BBA") were commissioned by Aurizon to update the mineral reserve estimates for the different zones of the property. Scott Wilson RPA reviewed the mineral reserve estimate on Zones 109 and 115, and updated the mineral resources of existing West Mine zones. BBA prepared a mineral reserve estimate on the East Mine crown pillar. Golder Associates Ltd. prepared an updated mining plan for the Lower Inter zone, based upon an updated mineral resource estimate prepared by Scott Wilson RPA.
The following assumptions were used in the estimates of mineral reserves:
- For the underground operation, the selected mining method is sequential transversal long hole when the vein is larger than 10 metres and sequential transversal or longitudinal long hole retreat when the vein is less than 10 metres. The stoping sequence includes cemented rockfill of the primary stoping sequence, cemented and unconsolidated rockfill for the longitudinal retreat and unconsolidated rockfill for secondary stoping sequence.
- Stope dilution has been calculated from numerical modeling on the basis of the stability of the stope openings, ore deposit geometry and mining method. The amount of dilution was reduced for stopes of smaller dimensions on the fringes of the zone, and increased for stopes with unfavourable geometry. In addition, each stope was assigned a backfill dilution percentage based on number of walls of fill and type of mucking floor. As a result, dilution averages 18-20%
- Minimum underground mining widths of two to three metres were used.
- The East mine crown pillar open pit is designed to a depth of 80 meters with an overall pit slope of 35 degrees.
Reconciliation of Casa Berardi mineral reserves
The following table outlines the primary factors impacting mineral reserves during 2007 following the actual experience gained during the first year of production at Casa Berardi.
Joanna
The property is located along the Cadillac Break, 20 km East of Rouyn-Noranda just off highway 117. The property was mined previously from underground to a maximum depth of 200m (46,000 tonnes at 6.6 grams of gold per tonne).
At Joanna, previous surface and underground exploration focused mainly on a poorly developed stacking of high grade veins within sediments. The veins were included within a 15 to 60 metres wide lower grade halo of 0.8 to 2.0 gram of gold per tonne. Compilation of existing data indicates that the corridor could be extended along a 1,800 metre trend and can currently be followed down to a depth of 400 metres. Mineralization follows multiple distinct zones, along a dip of 50º to the north with a western plunge.
Geostat Systems International Inc. ("Geostat") was commissioned by Aurizon to prepare a mineral resources estimate as at September, 2007, in accordance with the Standards of Disclosure for Mineral Projects as defined by N1 43-101. Details are contained in a technical report prepared by Geostat entitled "Resource Modeling Estimation Update -- Joanna Gold Deposit" dated October 26, 2007, a copy of which has been filed under the Company's profile at www.sedar.com. No updated resource estimate was prepared as of December 31, 2007.
For the East block, a minimum cut-off grade of 0.5 grams of gold per tonne was used. For the West block, a minimum cut-off grade of 0.5 grams of gold per tonne was used for intercepts between the surface and a depth of 150 metres, and a minimum cut-off grade of 1.5 grams of gold per tonne was used for intercepts between a depth of 150 metres and 300 metres.
Outlook
At Casa Berardi, the three year program initiated last year to transfer the existing mineral resources to mineral reserves will intensify.
- A re-assessment of the Principal Zones, located one kilometre east of the West Mine is in progress, evaluating the potential for underground and open pit mining. As the 280 metre level is rehabilitated, drilling will be initiated early in the second quarter, starting along the Principal Zones, to be followed by drilling to test the area between Principal Zones and the East Mine.
- As the re-assessment of the East Mine below the 100 metre level is complete, drilling and an economic study will be initiated with the objective of transferring the existing mineral resources to mineral reserves.
- An exploration drift will be developed at the 810 metres level, east of Zone 113 and to the south of the Casa Berardi fault, to provide drill access to test the depth extension of Zone 113 and to test the continuity and extension of Zones 122 and 123-South
At Joanna, four rigs are currently active along the lateral and dip extension of the mineral resources contour with the objective of increasing the existing mineral resources. An updated technical report on Joanna is in progress with emphasis on the upper part of the East block of mineral resources, above the 200 metre level.
Quality control
Mineral resource estimates, implementation and the quality control program are supervised by Jeannot Boutin P.Eng., Superintendent, Mine Geology for Casa Berardi and Ghislain Fournier P.Eng, Manager, Corporate Development for Joanna, both "qualified persons" as defined by the National Instrument 43-101.
Information of a technical and scientific nature in this press release has been prepared under the supervision of
Michel Gilbert, P.Eng., Vice President, a "qualified person" under National Instrument 43-101
Additional information
A sketch is attached showing the mineral reserve and/or resource outlines at the Casa Berardi Gold Mine and Joanna Gold Project. All other information previously released on Casa Berardi and Joanna is also available on the Aurizon website at http://www.aurizon.com.
Aurizon is a gold producer with a growth strategy focused on developing its existing projects in the Abitibi region of north-western Quebec, one of the world's most prolific gold and base metal regions, and by increasing its asset base through accretive transactions. Aurizon shares trade on the Toronto Stock Exchange under the symbol "ARZ" and on the American Stock Exchange under the symbol "AZK". Additional information on Aurizon and its properties is available on Aurizon's website at http://www.aurizon.com.
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AURIZON MINES LTD. |
David P. Hall, President and C.E.O. |
Ian S. Walton, Executive Vice President & C.F.O. |
Telephone: 604-687-6600
Toll Free: 1-888-411-GOLD
Fax: 604-687-3932 |
Web Site: www.aurizon.com; Email: info@aurizon.com |
or |
Renmark Financial Communications Inc.
2080 Rene-Levesque Blvd. West
Montreal, QC
H3H 1R6
Barry Mire: bmire@renmarkfinancial.com
Jen Power: jpower@renmarkfinancial.com
Media - Vanessa Napoli: vnapoli@renmarkfinancial.com
Tel: (514) 939-3989 Fax: (514) 939-3717 |
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