- Published: 10 December 2008
- Written by Editor
ECU Silver Significantly Increases NI 43-101 Mineral Resource Estimate
Mineral Resource Estimate Highlights
- Measured & Indicated Resources of 40 million oz silver equivalent.
- Inferred Resources of 391 million oz silver equivalent.
ECU Silver Mining Inc. ("ECU Silver" or the "Company") (TSX:ECU) is pleased to report the results of its fourth National Instrument 43-101 ("NI 43-101") compliant mineral resource estimate (the "Resource Estimate") on its Velardena District Properties in Durango State, Mexico ("Velardena"). The results confirm a silver equivalent increase in Measured & Indicated resources of 6% to 40 million ounces ("oz") and an Inferred resource increase of 118% to 391 million oz of silver equivalent.
NI 43-101 Resource Estimate:
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Silver Equivalent Silver Equivalent
(Gold and Silver) (All Metals)
(ounces) (ounces)
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Measured & Indicated 36,486,000 39,706,000
Inferred 248,109,000 391,024,000
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We plan to complete and file a technical report for the Resource Estimate on SEDAR within 45 days of this press release. The Resource Estimate, which was audited by MICON International Limited ("MICON"), is outlined in more detail in Tables 1, 2 and 3 below.
Michel Roy, the Chairman and CEO of ECU Silver stated, "Our objective in our recent exploration campaign was to convert some of our Mineral Potential into the Inferred category. This was successfully done and we now have an inferred mineral inventory of 391 million oz and measured and indicated of 40 million oz of silver equivalent establishing Velardena among the larger silver and gold projects in Mexico. This increase in our mineral resources is the largest in the history of the Company. After only three and a half years, our exploration team has increased our mineral inventory by over 18 times."
Stephen Altmann, the President of ECU Silver added that, "The growth of our mineral resource has shown remarkable advance. Exploration efforts at Velardena have consistently yielded excellent results with several veins still open laterally and at depth. It is worthwhile to note that about 66% of our mineral inventory is comprised of precious metals. The high content of both gold and silver highlights the significance of this resource as a primary precious metal project."
Many of the veins and vein packages at Velardena have demonstrated reliable evidence of lateral continuity in both directions and at depth. We are able to quantify this additional potential by providing an estimate of mineral potential ("Mineral Potential") which has been reviewed by MICON (refer to Table 4 below for additional details).
- Mineral Potential: 569,524,000 to 930,400,000 ounces of silver equivalent.
This Mineral Potential has been estimated on a silver and gold basis only and does not include any silver equivalent estimates derived from base metal values.
A mineral potential is not a mineral resource, is conceptual in nature and must be stated as a range since it cannot be estimated to the same accuracy as a mineral resource. Disclosure of the Mineral Potential is compliant with NI 43-101 disclosure requirements and reflects the potential lateral and downward extensions of veins identified in the Resource Estimate.
The Mineral Potential differs in two ways from what we last reported. First, it decreased from the last reported results due to our success in converting certain zones of Mineral Potential into the Inferred category. Second, it increased as new veins and areas within Velardena were added to Mineral Potential.
ECU believes that the potential to increase mineral resources at Velardena continues to be substantial. While the Mineral Potential is not included in the Resource Estimate, MICON has reviewed and approved the conceptual nature of the Mineral Potential.
The material increase in the Resource Estimate and the Mineral Potential was based solely on veins included in this resource estimation and does not incorporate other known veins identified through historical data within Velardena, nor does it include the mineralized skarns. Insufficient data has been collected to estimate mineral resources in these other veins.
The Resource Estimate is based on 46 veins and includes the sum of mineral resources from the main Velardena Property, the Chicago Property and 50% of the joint venture San Diego Property. All of these properties are within close proximity to each other. Additional veins at Velardena, which are well known and have been identified through surface sampling and/or underground workings, require further evaluation. Also, a number of veins have not been included because current assays did not meet the cut-off criteria. Furthermore, it is anticipated that more veins exist in the Velardena Properties based on past geological mapping.
A cut-off value of US$45 per tonne (166 grams per tonne) was used for the narrow veins and was based on information derived from previous mining activities on the main Velardena Property. A cut-off value of US$25 per tonne (92 grams per tonne) was used for the bulk tonnage vein packages and was based on previous bulk mining tests completed by ECU Silver. In determining the silver equivalent value, the Net Smelter Return ("NSR") value was calculated for each commodity based on metallurgical recoveries from the most recent tests and contracts for mineral concentrates produced from the mining activities on the Velardena Property.
Past resource estimates in respect of the Velardena Properties have been set out in previous N.I. 43-101 technical reports as summarized in Table 5 below.
The qualified persons within the meaning of NI 43-101 responsible for the evaluation of the Resource Estimate are William J. Lewis, B.Sc., P. Geo., a senior geologist with MICON based in Toronto, Canada, and Michel Roy, P. Geo., the Chairman and CEO of ECU Silver.
The Company would like to thank MICON for their efforts and guidance in preparing the Resource Estimate.
Cautionary Statements:
Readers are cautioned that there are no assurances that all or any part of the Resource Estimate or that all or any part of the Mineral Potential will be economically viable and although the information in this press release is based on the best available data the Company has collected to date, a material difference between the actual results and the Company's expectations may arise once further exploration is completed.
Until a prefeasibility study is completed, there are no assurances the release of an updated mineral resource will be economically viable.
The mineral potential of the Velardena District property is conceptual in nature and there has been insufficient exploration conducted within the mineral potential evaluation to define a mineral resource. It is also uncertain if further exploration will result in the targets being delineated as mineral resources.
About ECU Silver
ECU Silver Mining Inc. is focused on the exploration, development and mining of precious and base metals at its Velardena District Properties in Durango, Mexico. The area is comprised of three properties, the Main Velardena Property, the Chicago Property and the San Diego Joint Venture Property. The properties contain a measured and indicated mineral resource of 40 million silver equivalent ounces and an inferred mineral resource of 391 million silver equivalent ounces. ECU's mission is to become a pre-eminent silver and gold producer through the development of existing and additional potential resources in the Velardena district. ECU Silver is listed on the Toronto Stock exchange under the symbol ECU.
Statements in the release that are "forward-looking statements" are based on current expectations and assumptions that are subject to risks and uncertainties. Actual results could differ materially. We undertake no duty to update any forward-looking statement to conform the statements to actual results or changes in our expectations.
PRESS RELEASE TABLES
Table 1:
Mineral Resource Summary(1)
Velardena District Properties
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Silver Silver
Gold Silver Equivalent(2) Lead Zinc Equivalent(2)
(Au) (Ag) (Au+Ag) (Pb) (Zn) (All metals)
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000 oz 000 oz 000 oz 000 lb 000 lb 000 oz
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Measured 203 9,463 23,606 12,780 22,023 25,249
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Indicated 90 6,665 12,880 13,444 14,707 14,456
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Measured
& Indicated 293 16,128 36,486 26,224 36,730 39,705
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Inferred 1,759 135,400 248,109 1,002,389 1,214,142 391,024
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(1) Resource estimates are based on a NSR value cut-off of US$45 per tonne
and US$25 for vein packages.
(2) Silver equivalents incorporate the following assumptions:
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Price(1) Oxide Sulphide Recovery Zones
US$/oz Recovery High Low Bulk Chicago San
Pb/Zn Pb/Zn Diego
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Gold 775/oz 78% 72% 69% 65% 69% 44%
Silver 14.00/oz 58% 60% 59% 57% 65% 65%
Lead 0.90/lb n/a 67% 55% 55% 54% 73%
Zinc 1.28/lb n/a 44% 46% 46% 36% 48%
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(1) Commodity price assumptions are based on three year trailing averages
plus 6% for gold and 3% for silver.
Table 2
Mineral Grade Summary - Oxides
Velardena District Properties
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Gold Silver Lead Zinc Silver
Tonnes (Au) (Ag) (Pb) (Zn) Equivalent
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000 t g/t g/t % % g/t
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Measured 668 3.36 156 n/a n/a 420
Indicated 407 2.27 172 n/a n/a 351
Measured
& Indicated 1,075 2.95 162 n/a n/a 394
Inferred 379 1.68 186 n/a n/a 318
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Table 3
Mineral Grade Summary - Sulphides
Velardena District Properties
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Gold Silver Lead Zinc Silver
Tonnes (Au) (Ag) (Pb) (Zn) Equivalent
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000 t g/t g/t % % g/t
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Measured 2,205 1.84 86 0.26 0.45 229
Indicated 669 2.80 205 0.91 1.00 459
Measured
& Indicated 2,874 2.06 114 0.41 0.58 282
Inferred 26,141 2.07 158 1.74 2.11 461
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Table 4
Mineral Potential Summary
Velardena District Properties
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Mineral Mineral Avg. Avg. Potential
Potential Potential Gold Silver Contained
Range Grade Grade Silver Eq.
(Au + Ag)
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000 t g/t g/t 000 oz
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Minimum 41,692 2.83 207 569,524
Maximum 87,186 2.06 167 930,400
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Table 5
Previous Resource Estimates
Velardena District Properties
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Release July June January November
Date 2005 2006 2008 2008
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Report July October March Est: January
Date 2005 2006 2008 2009
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MICON MICON
Auditor Roscoe, Postle Broad Oak and International International
and Associates Associates Limited Limited
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Mineral Resources -Silver Equivalent Ounces (millions)
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Meas. &
Ind. 12.2 17.4 37.7 39.7
Increase n/a 42% 117% 6%
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Inferred 11.4 81.0 179.0 391.0
Increase n/a 608% 121% 118%
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Mineral Potential -Silver Equivalent Ounces (millions)
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Minimum 4.5 33.0 464.7 569.5
Increase n/a 633% 1308% 23%
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Maximum 10.0 55.0 806.5 930.4
Increase n/a 450% 1366% 15%
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ADDITIONAL INFORMATION
Resource Methodology
1. Measured, Indicated and Inferred resource tonnages were estimated using longitudinal sections for each of the veins and/or vein packages combined with the width and density information for each cross-section for the measured and indicated resources and on the average widths and densities of all intercepts for the inferred.
2. The geological continuity of each zone was determined on 20 metre cross sections based on stratigraphy, mineralization and structure using underground development and sampling plus diamond drill holes and surface information when applicable.
3. The area of these blocks was measured on long sections (oriented vertically but parallel to strike of the vein) using MineSight
4. For new areas added to the database since the last NI 43-101 report as well as all of the San Diego project information, the areas were divided in polygons, using the ProMine software, centered on each data point and limited by the general area determined by the above mentioned parameters. The results from each data point were then applied to the corresponding polygon and tonnes and grades estimated for each.
5. All intercepts were evaluated at a 1 metre minimum horizontal width for narrow veins and at a 2.70 metre minimum horizontal width for the bulk mining areas with representative local background values for internal dilution in both cases.
6. The undiluted resource was estimated using an NSR value cut-off factor of US$45 per tonne for the narrow, high grade veins, whereas a cut-off factor of US$25 per tonne was applied to the bulk tonnage vein packages. Blocks that did not meet these criteria were removed from the Resource Estimate. However, in parts of the measured and indicated resources, there remained internal blocks that did not meet the above criteria but would naturally be part of the mining sequence. These blocks were included in the resource estimate provided the overall grade of the mining level was above the NSR value cut-off factor.
7. Capping of high values was set at the 95th percentile of all assay results calculated for each element in each vein for the measured and indicated resources.
8. Measured Resources were defined as that portion of mineralization between mine levels, 10 metres on each side of the drifts and 25 to 50 metres below the lowest drifts depending on proven vertical continuity.
9. Indicated Resources were defined to a vertical depth of 25 metres below Measured Resources and 10 metres laterally adjacent to Measured Resources.
10. Inferred Resources were defined as that portion of mineralization defined by surface sampling and/or drill-hole samples. The extent of the mineralization was defined by geology or in most cases where the extent of the mineralized zone is unknown, the extent of the Inferred Resources has been estimated at a maximum of 100 metres with the following exceptions: 50 metres was used for the lateral extension for the veins on the San Diego property and for Santa Juana the depth of Inferred Resources for those zones which have been explored by drill holes has been set at 50 metres below the lowest mineralized drill intersection for the whole package of veins.
11. Mineral Resources that are not mineral reserves do not have demonstrated economic viability.
Estimate of Mineral Potential
The mineral potential of a property cannot be estimated to the same accuracy as a mineral resource and must be stated as a range. To estimate a range for the grades, a factor of minus 10 % was applied for the downside and plus 10 % for the upside potential. In the potential for the extensions of the veins belonging to the Santa Juana vein system where grades were used from drill holes only, the upside was set at plus 50%.
The upside potential factor is larger than the downside potential factor because of the possibility that the mineralized zones will be similar in nature to, and as extensive as, the main veins on the Velardena Properties. Consequently a significant difference between the grades from drilling and the higher grades from stoping is expected.
Furthermore, an additional 75,693,747 ounces silver-equivalent was added to both the minimum and maximum to reflect the fact that gold and silver grades from actual stopes were significantly higher than grades from drill holes that defined those blocks prior to mining them. The increase was material in all cases and averaged approximately 300% using four well documented cases. Using the three smallest increases for gold and silver, the average increase obtained was 93% for gold and 134% for silver. This difference was applied to the 6,207,471 tonnes grading 3.05 g/t gold and 146 g/t silver representing the inferred resources at Santa Juana which were based uniquely on drill-hole information, yielding the potential increase mentioned above.
MICON also indicated that contributing to the upside potential is the possibility that additional veins on the Velardena Properties may be discovered.
The mineral potential of the Velardena District property is conceptual in nature and there has been insufficient exploration conducted within the mineral potential evaluation to define a mineral resource. It is also uncertain if further exploration will result in the targets being delineated as mineral resources.
However, a multi-phase exploration program is being proposed to test the areas concerned, as was done in 2006 and 2007 which resulted in the conversion of most of the then mentioned Potential for the target areas into Inferred Resources.
Methodology to Estimate Tonnages in Potential
1. The maximum lateral extent of the Mineral Potential was estimated using the known lateral extent, from geological mapping, of the veins which exhibited surface expressions and carrying the Mineral Potential to the limits of the surface expressions.
2. The lateral extent of the Mineral Potential on veins not having any surface expression was set at a maximum of 400 metres, unless the property boundary or a fault was encountered whereupon the lateral extent was cut to that distance.
3. The maximum dip extension of the Mineral Potential was set at 600 metres, 400 metres for San Diego, based on the known mined height of the major veins systems, unless the property boundary or a fault was encountered whereupon the dip extent was cut to that distance.
4. The minimum lateral extent of the Mineral Potential was estimated by extending laterally for 200 metres plus half the remaining maximum lateral extent, unless the property boundary or a fault was encountered whereupon the lateral extent was cut to that distance.
5. The minimum dip extension of the Mineral Potential was estimated by extending vertically at depth for 300 metres, 200 metres for San Diego, unless the property boundary or a fault was encountered whereupon the dip extent was cut to that distance.
6. Once a surface area was obtained from the above criteria, vein width, density and grades from the nearest resource blocks were applied to estimate the tonnages and the base case for the grades, the range for the grades then being used according to the criteria explained above.
SOURCE: ECU Silver Mining Inc.
ECU Silver Mining Inc. Michel Roy Chairman and CEO 011 52 871 747 5750 ECU Silver Mining Inc. Stephen Altmann President (416) 366-2428 (416) 366-8131 (FAX) Website: www.ecu.ca
