International Minerals Corporation
Swiss : IMZ

International Minerals Corporation

September 26, 2005 09:00 ET

International Minerals Announces Initial Inferred Resource Estimate at Pallancata Silver-Gold Property, Peru; Estimated 39 Million Ounces Silver and 147,000 Ounces Gold

SCOTTSDALE, ARIZONA--(CCNMatthews - Sept. 26, 2005) - International Minerals Corporation ("IMC") (TSX:IMZ)(SWX:IMZ)(FWB:MIW) is pleased to announce an initial mineral resource estimate at its 100%-held Pallancata silver-gold property, located approximately 240km southeast of Ayacucho in southern Peru. Based on core drilling to date (56 drill holes totaling 13,923m) IMC has calculated an Inferred Resource estimate for the Pallancata vein-breccia deposit of 2.7 million tonnes at an average grade of 445 g/t silver and 1.7 g/t gold containing approximately 38.6 million ounces of silver and 147,000 ounces of gold at a cut-off grade of 150 g/t silver, using uncut metal values (see Table below). Mineralization within the Pallancata structure remains open along strike and at depth.

Currently IMC has identified four principal areas of epithermal, low-sulfidation, silver-gold mineralization in vein-breccia structures on the Pallancata property, designated by IMC as: Pallancata, Mariana, Soroche and San Javier (see Figure 1). Although the Pallancata vein-breccia structure has been the primary focus of IMC's drill program to date, high-grade silver values are also reported from drilling in the Mariana and San Javier areas. Drill assay results for these areas are shown in Appendix 1, together with results from the previously unreported drill-hole (PAC-56) on the Pallancata structure. At this time, there is insufficient drilling to calculate a resource estimate for the Mariana and San Javier areas (a total of 2,065m in 12 drill-holes). Follow-up drilling is planned in those areas in the next phase of the exploration program, together with initial drilling in the Soroche area.

Pallancata Main Vein Structure - Inferred Mineral Resource Estimate

The complex Pallancata vein-breccia structure is hosted in Tertiary volcanics and the presently known mineralized zone is approximately 2.0 km long, up to 300m in vertical extent and up to 40m wide, including the intensely silicified wall rocks. Individual veins (and splays), however, are more typically 0.5m to 3.0m wide. Much of the high-grade mineralization occurs in the West Breccia Zone (located in the western part of the structure) and comprises an intensely silicified body with a strong stockwork of quartz veins, typically with a northeast-southwest to north-south strike. High-grade zones (often grading several kilos of silver per tonne) are present where these veins intersect the northwest-southeast striking main Pallancata structure.

Table 1 below shows IMC's initial Inferred Resource estimate based on two different silver cut-off grades (see next page for explanation). All assay values are based on uncut metal values and numbers are rounded to reflect the precision of the resource estimate. Further geostatistical analyses, based on additional data, are required to determine the appropriate grades for cutting metal values in a more advanced modeling exercise.

Table 1. Pallancata Main Vein - Inferred Mineral Resource Estimate

Cut-off Grade Silver Gold Silver Gold
(g/t silver) Tonnes (g/t) (g/t) Ounces Ounces
75 4,652,000 309 1.2 46,150,000 179,600
150 2,698,000 445 1.7 38,600,000 146,600
Note: The silver and gold resources are not mineral reserves and
do not have demonstrated economic viability.

Figure 2 (attached) is a longitudinal section through the main Pallancata Vein showing the location of the core drill-holes used in IMC's mineral resource estimate (see the Company's news releases dated September 19, 2003, December 8, 2004 and May 24, 2005 for assay results for these drill-holes).

Due to the limited amount of drill-hole data available at this stage, the Inferred Resource was estimated on a simple polygonal basis on vertical cross-sections spaced 50m apart using length-weighted average grades to generate a silver and gold grade for each polygon. The average drill-hole density is approximately 50m by 150m where there is sufficient drilling, and greater where there are sections without drill-holes. The simplicity of this technique reflects the preliminary level of data available. When the density of in-fill drilling is higher, a more advanced methodology (such as "inverse-distance weighting" or "kriging") will be used to determine an updated resource estimate.

Silver mineralization outlines for the polygons were defined at an initial 75 g/t silver cut-off to assist in outlining the overall shape, continuity and scope of the mineralization at a relatively low cut-off grade. Geological boundaries and vein interpretations were used to guide these outlines. Polygonal outlines were extended to match the geological interpretation using both adjacent sections and surface mapping/sampling results as guides. Where no other information existed, the outlines were extended approximately 50m. Using the 75 g/t outlines as a guide, new polygonal outlines were then drawn and grades interpolated at a more realistic (from an economic aspect) 150 g/t silver cut-off. Good continuity of mineralization was found at both the 75 g/t and 150 g/t silver grade levels.

Silver and gold grades were interpolated into each grade-shell using a length-weighted average of all the intersections within that shell and on that section. Each grade shell was assigned a specific gravity of 2.33 g/cm3 (based on results from 490 drill samples). A thickness of 50m was used (half-way to next section) except when there was no drilling on an intermediate section but there was minimum cut-off grade present on both of the adjacent sections. In this case the adjacent sections were projected into the section without drill coverage.

The Inferred Resource estimate was carried out in accordance with National Instrument ("NI") 43-101 by IMC Qualified Person, Technical Manager Nick Appleyard and reviewed and verified by Independent Qualified Person, Mark Cannuli. A Technical Report, in accordance with NI 43-101, is currently in preparation by the Independent Qualified Person and will be filed by IMC within the next 30 days.

Based on the results to date for the main Pallancata vein-breccia structure, IMC intends to commence a pre-feasibility study as soon as possible, funded by existing IMC financial resources. This study will commence with an initial metallurgical testing program in October 2005, to be followed by an extensive drilling program. In addition, follow-up drilling will also be carried out in the other mineralized areas on the Pallancata property.

Core drilling was carried out by Bradley Brothers of Rouyn, Quebec, Canada using Canadian drillers. Sample preparation and analytical work was undertaken at the ALS Chemex laboratory in Lima, Peru using standard industry practices and conventional atomic absorption and/or fire assay methods for silver and gold. For quality control purposes, analytical standards with known metal values were included with IMC's samples and show acceptable reproducibility. In addition, duplicate analyses on selected drill samples were carried out by a second independent assay laboratory (SGS, Lima) and show excellent reproducibility. The drilling phase of the exploration program was conducted under the supervision of IMC Qualified Person, Consulting Economic Geologist, John Sutcliffe.


Stephen J. Kay, President and CEO

To view Figure 1 please click on the following link:

To view Figure 2 please click on the following link:

To view Appendix 1 please click on the following link:

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