Quadra Mining Ltd.
TSX : QUA

Quadra Mining Ltd.

July 06, 2005 09:00 ET

Quadra Mining Announces Independent Resource Estimate for Sierra Gorda Project in Chile

VANCOUVER, BRITISH COLUMBIA--(CCNMatthews - July 6 2005) - Quadra Mining Ltd. (TSX:QUA) is pleased to announce the completion of an independent NI 43-101 compliant mineral resource estimate for the Sierra Gorda project in Chile. The mineral resource estimate is classified as Indicated and Inferred and consists of oxide, supergene and hypogene copper resources and hypogene molybdenum resources.

The Indicated sulphide mineral resource is estimated at 215 million tonnes of 0.38% copper and 0.066% molybdenum resulting in a 0.71% copper equivalent grade based on a 0.34% copper equivalent cutoff grade ("CuEq"). An additional 182 million tonnes of an Inferred sulphide mineral resource grading 0.34% copper and 0.024% molybdenum, with a copper equivalent grade of 0.46% are also reported at the same cutoff grade.

The Indicated oxide mineral resource is estimated at 181 million tonnes of 0.37% copper based on a 0.20% copper cutoff (molybdenum is not recovered from oxide material and therefore is not included in the oxide and supergene resource tabulation). An additional Inferred oxide resource of 36 million tonnes at a copper grade of 0.29% is also reported using the same cutoff grade. The supergene copper (heap leach recoverable) is reported with the oxide, although it could be processed with the oxide or hypogene sulphide.

Paul Blythe, President comments, "This initial resource estimate for Sierra Gorda confirms the significance of the deposit for Quadra and the results support our plans for the advancement of the project. We find the results for the primary sulphide particularly encouraging with around 100M tonnes grading 1.0% CuEq at a 0.6% CuEq cutoff grade. A 15,000-metre RC drill program is now in progress, designed to build on our knowledge of the property. The primary objective is to expand the oxide resource around defined mineralized zones and to delineate additional economic copper oxide targets in five previously untested areas using the geophysics and structural knowledge that we have gained to date. This drilling is part of a US$3.8 million exploration program budgeted for 2005."

The Sierra Gorda copper and molybdenum resource estimate is given below and a figure of the resource area is attached. To view the map accompanying this press release please click on the following link: http://www2.ccnmatthews.com/database/fax/2000/QUAmap.pdf

While mineral resources do not have demonstrated economic viability, future economic studies will determine what percentage of this material can be placed into the mineable category.



Estimated Sulphide Resource
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Total Total
Con- Con-
Cutoff Grade Grade tained Cu Grade tained Mo
Grade Tonnes CuEq(2) Cu Cu lbs Mo Mo lbs
%CuEq(1) (000's) % % (Tonnes) (000's) % (Tonnes) (000's)
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Indicated Resource - Sulphide Material
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0.34 215,100 0.71 0.38 810,000 1,789,500 0.066 141,000 311,600
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0.40 187,500 0.75 0.39 740,000 1,629,000 0.072 135,000 298,600
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0.50 135,500 0.87 0.42 570,000 1,258,000 0.090 123,000 270,200
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0.60 96,600 1.00 0.44 430,000 943,600 0.112 109,000 239,500
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0.70 72,700 1.13 0.47 340,000 751,100 0.131 95,000 210,200
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Inferred Resource - Sulphide Material
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0.34 182,200 0.50 0.38 700,000 1,534,600 0.024 43,000 95,000
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0.40 142,000 0.54 0.40 570,000 1,263,500 0.027 38,000 83,500
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0.50 67,700 0.64 0.45 300,000 667,800 0.038 26,000 56,200
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0.60 30,900 0.76 0.49 150,000 330,800 0.052 16,000 35,500
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0.70 14,700 0.87 0.52 80,000 168,900 0.069 10,000 22,200
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Estimated Oxide and Supergene Resource
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Cutoff Grade Total Cu
Grade Tonnes Cu Contained Cu lbs
% Cu (000's) % (Tonnes) (000's)
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Indicated Resource - Oxide Material
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0.20 180,770 0.37 660,000 1,464,580
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0.30 92,910 0.48 450,000 991,150
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0.40 47,890 0.62 300,000 652,110
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0.50 28,090 0.74 210,000 459,680
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Inferred Resource - Oxide Material
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0.20 36,470 0.29 104,000 229,660
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0.30 10,203 0.41 42,000 93,040
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0.40 3,669 0.55 20,000 44,280
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0.50 1,829 0.66 12,100 26,570
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(1) The minimum cutoff grades were determined using the operating costs for similar operations in Chile published by Brook Hunt.

(2) Copper equivalent calculation is based on long term average copper and molybdenum metal prices to arrive at a ratio of 5 to 1. Copper equivalent calculations reflect gross metal content and have not been adjusted for metallurgical recoveries or relative processing and smelting costs.

The mineral resource estimate is based upon assay results from 47,664 metres of drill core from 129 holes (surface and underground) and 29,015 metres of reverse circulation (RC) drilling in 160 holes. The majority of this drilling was performed by previous operators. Quadra has re-assayed samples to validate historic data, resurveyed drill collars and verified the underlying data of these earlier holes. Those holes that could not be completely verified or for which some doubt still exists, were not used for resource estimation. The resource estimate is reported to a depth of 650 m or elevation 1034 m and the potential for additional primary hypogene mineralization at Sierra Gorda is for the most part untested.

Quadra began its Sierra Gorda development program in April 2004. Since then, the Company has expended approximately $2.6 million on work that has included a 50-hole, 10,712-metre RC drill program, geophysical surveys, detailed mapping and geological modeling.

Exploration to date has determined that copper oxide mineralization continues from near surface to depths ranging from 150 metres to 200 metres below the surface. This would imply that any future operation would consist of an initial copper oxide leach, with conventional sulphide flotation open pit mining operations to commence once the oxide operation had sufficiently exposed the sulphide deposit. Some of the strongest molybdenum mineralization identified to date occurs locally at the oxide - sulphide copper interface. This is economically significant as it would allow for the extraction of high-grade Cu-Mo sulphide mineralization early in a Cu-Mo sulphide mine plan.

The Sierra Gorda project comprises four contiguous properties that cover an area of 19 km 2 and is located in the Atacama Desert in an area of Chile that hosts a number of significant copper mines and resources. The infrastructure is well developed in this region and the project lies two kilometres away from the main highway and rail line connecting Antofagasta and Calama.

The resource estimate and associated work was prepared in compliance with requirements set out in National Instrument 43-101 by Steven Ristorcelli, P.Geo., Mine Development Associates ("MDA") of Reno, Nevada, assisted by Peter Ronning, P.Eng, New Caledonian Geological Consulting (NCG) with the QA/QC work reviewed by Mr. Gary Lustig, P. Geo. The report describing the estimate will be filed as a Technical Report and posted on SEDAR within 30 days.

The Sierra Gorda project exploration work was conducted under the direction of Brian P. Fowler, P.Geo, the Qualified Person for the project and Manager, Exploration for Quadra Mining Ltd. Mr. Fowler has reviewed and approved the content of this press release.

About Quadra Mining Ltd. (TSX:QUA)

Quadra is a British Columbia corporation based in Vancouver and is a mining company whose principal asset is the Robinson Mine in Nevada. The Company has a goal of becoming a mid-tier base metals development and operating company with interests in a number of advanced exploration, development and producing properties.

This press release may contain some forward-looking statements that are subject to risks and uncertainties that may cause actual results to differ from those expressed or implied by such statements. Statements relating to revenues, growth, profits and operating expenses depend on future market conditions and risks, and are considered forward-looking thereby providing no guarantee that they will be realized.

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