- Published: 23 March 2009
- Written by Editor
Red Back Mining Inc.: 39% Increase in Tasiast Reserves (119% Since August 2007)
Red Back Mining Inc. (the "Company" or "Red Back") (TSX:RBI) is pleased to announce a significant increase in Proven and Probable Reserves at its 100% owned Tasiast Gold Mine ("Tasiast") in Mauritania and a similar increase in Measured and Indicated Resources.
Tasiast Reserves
The Company's consultants, AMC Consultants, have re-estimated Ore Reserves for the Tasiast mine. The new Ore Reserve estimate, shown in the table below, is reported as at 31 December 2008.
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Tonnes Au In situ Au
Classification (Mt) (g/t) (Moz)
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Total Proven 27.2 1.48 1.30
Total Probable 20.1 1.46 0.94
Total Stockpile 1.7 0.89 0.05
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Total 49.0 1.45 2.28
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- Numbers may not add correctly due to rounding
- The Ore Reserve estimate was made using a gold price of US$700, no change
from previous Ore Reserve estimate
- Cut-off grades: CIL oxide 0.78g/t, CIL fresh 0.86g/t, Dump leach oxide
0.12g/t.
The reserve represents a 39% increase over the previously reported reserve (News Release: April 7, 2008). Red Back has now increased reserves at Tasiast by 119% in the 19 months since it acquired the project in August 2007.
The current Ore Reserves include the CIL and Dump Leach components for Piment and the CIL component for West Branch (refer to attached Map for location of deposits).
To view the attached map, please click on the following link: http://media3.marketwire.com/docs/rbi0323.jpg.
The estimated split of reserves by processing method is set out below:
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Tonnes Au In situ Au
Classification (Mt) (g/t) (Moz)
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CIL Circuit
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Proven 17.8 2.05 1.18
Probable 13.7 1.95 0.86
Stockpile 0.9 1.17 0.03
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Total CIL Circuit 32.4 1.99 2.07
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Dump Leach
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Proven 9.4 0.40 0.12
Probable 6.3 0.38 0.08
Stockpile 0.8 0.61 0.02
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Total Dump Leach 16.5 0.40 0.21
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- Numbers may not add correctly due to rounding
- Piment zone oxide ore between 0.12g/t and 0.90g/t was allocated to the
Dump leach Process.
A Dump Leach operation to process low grade oxide ore from the Piment zone is in its final stages of commissioning, with commercial levels of recoveries expected in the second quarter.
Test work is ongoing to extend the oxide Dump Leach reserves to include material from the West Branch area. In addition, following positive initial results, test work to investigate the potential for heap leaching low grade fresh material is also being accelerated. Upon completion of this test work, low grade oxide and fresh material from West Branch and low grade fresh material from Piment is expected to be converted to Ore Reserves. A new reserve estimate will be released in the third quarter incorporating this material.
Tasiast Resources
Measured and Indicated Resources, using a cut off grade of 1 g/t, have increased by 32% over the previously reported mineral resource estimate (News Release: June 12, 2008). The Company will now report resources on the basis of mining cut-off grades expected to be applied to the various ore types as well as at a 1 g/t cut-off grade for comparison purposes.
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Measured +
Measured Indicated Indicated Inferred
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Cut- Au Au Au Au
Zone Off Mt g/t Moz Mt g/t Moz Mt g/t Moz Mt g/t Moz
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Oxide 0.2 19.0 0.98 0.60 15.9 0.77 0.39 34.9 0.89 0.99 7.0 0.6 0.13
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Transition 0.5 5.0 1.28 0.20 4.3 1.13 0.16 9.2 1.21 0.36 0.9 1.1 0.03
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Fresh 0.5 20.5 1.48 0.98 32.7 1.32 1.39 53.2 1.38 2.37 15.6 1.2 0.62
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Total 44.5 1.24 1.78 52.9 1.14 1.94 97.4 1.19 3.72 23.6 1.0 0.78
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All ore
types 1.0 18.4 2.13 1.26 19.8 1.99 1.27 38.2 2.06 2.53 7.4 2.0 0.47
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- Minerals Resources are reported below the December 31 2008 mined surface.
- Figures may not add correctly due to rounding.
- Oxide is referred to as material amenable to Dump Leaching and comprises
oxide plus upper transition. Transition is lower transition which with
fresh material is potentially amenable to Heap Leaching.
- The resources are estimates of recoverable tonnes and grades using
Multiple Indicator Kriging with block support correction into 15 metres
(East) by 25 metre (North) by 5 metre (Elevation) model blocks and
assuming smallest mining unit for ore selection in mine grade control of
3 metres (East) by 5 metres (North) by 2.5 metres (Elevation).
- Measured resources lie in areas where drilling is available at a nominal
25 x 25 metre spacing, Indicated resources occur in areas drilled at
approximately 25 x 50 metre spacing and Inferred resources exist in areas
of broader spaced drilling.
- Gold estimation and model blocks were constrained within geologically
derived wireframes.
- Resources are inclusive of reserves.
Future Reserve/Resource growth
The current Measured and Indicated Resources are contained in a six kilometer length of strike of the sub-parallel Piment and West Branch structures. These structures have been traced by the Company over 20 km on surface and well over 70km via aerial geophysics. Only widely spaced step out drilling has been completed outside the current resource area. Current exploration programs are focused on the area 2km immediately to the South of the current resource area. The Tasiast structures remain highly prospective and Red Back intends to continue to provide resource and reserve updates on a regular basis.
Chirano
A resource/reserve update for the Company's Chirano Gold Mine in Ghana is expected before the end of the first quarter.
About Red Back
Red Back is an unhedged African focused gold producer. It owns and operates the Chirano Gold Mine in Ghana (90% interest) and the Tasiast Gold Mine in Mauritania (100% owned). Major plant expansions at both Chirano and Tasiast are advanced. Aggressive exploration programs aimed at increasing the Company's resource and reserve base at both Chirano and Tasiast are continuing.
The independent Resource estimate reported herein was undertaken by Nic Johnson (Member of the Australian Institute of Geoscientists) of Hellman and Schofield Pty. Ltd with more than five years experience in the use of geostatistics for estimation of recoverable resources in gold deposits. For the purpose of reporting under National Instrument 43-101 Mr. Johnson is regarded as a Qualified Person.
The independent Ore Reserve estimate reported herein was undertaken under the supervision of Patrick Smith (Member of the Australasian Institute of Mining and Metallurgy), Principal Mining Engineer of AMC Consultants Pty Ltd with more than five years experience in Ore Reserve estimation. For the purpose of reporting under National Instrument 43-101 Patrick Smith is regarded as a Qualified Person.
The technical contents of this release have been reviewed by Hugh Stuart, BSc., MSc, a Qualified Person pursuant to NI-43101. Mr. Stuart is the VP - Exploration of the Company and a Member of the Australasian Institute of Mining and Metallurgy. Samples are prepared and analyzed by fire assay using a 50 gram charge at the SGS facility at the Tasiast mine site in compliance with industry standards. Field duplicate samples are taken and blanks and standards are added to every batch submitted. Selected samples from this lab are check assayed each month at other SGS laboratories worldwide. This News Release contains forward looking statements which are subject to a variety of risks and uncertainties which could cause actual events or results to differ materially from those reflected in the forward looking statements. The Company does not intend to update this information and disclaims any legal liability to the contrary.
FORWARD-LOOKING INFORMATION
This press release contains "forward-looking information" that is based on Red Back's current expectations, estimates, forecasts and projections. This forward-looking information includes, among other things, statements with respect to Red Back's plans, outlook and business strategy. The words "may", "would", "could", "should", "will", "likely", "expect", "anticipate", "intend", "estimate", "plan", "forecast", "project", and "believe" or other similar words and phrases are intended to identify forward-looking information.
Forward-looking information is subject to known and unknown risks, uncertainties and other factors that may cause Red Back's actual results, level of activity, performance or achievements to be materially different from those expressed or implied by such forward-looking information. Such factors include, but are not limited to: uncertainties related to drilling results; the ability to raise sufficient capital to fund exploration; changes in economic conditions or financial markets; changes in prices for Red Back's mineral products or increases in input costs; litigation, legislative, environmental and other judicial, regulatory, political and competitive developments; technological or operational difficulties or inability to obtain permits encountered in connection with exploration activities; and labour relations matters.
This list is not exhaustive of the factors that may affect our forward-looking information. These and other factors should be considered carefully and readers should not place undue reliance on such forward-looking information. Red Back disclaims any intention or obligation to update or revise forward-looking information, whether as a result of new information, future events or otherwise.
On behalf of the Board of Directors,
Richard P. Clark, President
Red Back Mining Inc. Simon Jackson Vice President, Corporate Development (604) 689-7842 Red Back Mining Inc. Sophia Shane Investor Relations (604) 689-7842 (604) 689-5452 (FAX) Website: www.redbackmining.com
