SOURCE: International Minerals Corporation

International Minerals Corporation

February 24, 2011 18:00 ET

International Minerals Reports Increased Resource Estimate at Inmaculada Gold-Silver Project

SCOTTSDALE, AZ--(Marketwire - February 24, 2011) - International Minerals Corporation (TSX: IMZ) (SWISS: IMZ) (FRANKFURT: MIW) reports an updated, increased mineral resource estimate for the 40%-owned (Hochschild Mining plc 60%) Inmaculada gold-silver project in Peru.

Below is the updated resource estimate (on a 100% project basis) using a 3.0 grams/tonne ("g/t") gold equivalent cut-off grade as previously defined in IMZ's Preliminary Economic Assessment (see news release dated September 9, 2010 for details).

  • Measured Resource: 155,000 ounces ("ozs") gold and 4.1 million ozs silver (contained within 0.9 million tonnes ("mt") at an average grade of 5.1 g/t gold and 136 g/t silver).

  • Indicated Resource: 640,000 ozs gold and 24.2 million ozs silver (contained within 3.8 mt at an average grade of 5.2 g/t gold and 198 g/t silver).

  • Measured and Indicated Resource: 795,000 ozs gold and 28.3 million ozs silver (contained within 4.7 mt at an average grade of 5.2 g/t gold and 186 g/t silver).

  • Inferred Resource: 521,000 ozs gold and 21.0 million ozs silver (contained within 2.6 mt at an average grade of 6.1 g/t gold and 247 g/t silver).

Compared to the resource estimates announced in IMZ's September 2009 Preliminary Economic Assessment report, this new resource estimate represents a 29% increase in gold equivalent grade and a 60% increase in gold equivalent ounces in the Measured and Indicated categories and a 29% increase in gold equivalent grade and a 22% decrease in gold equivalent ounces in the Inferred category.

Details of the resource estimates at various cut-offs are shown in Table 1 below. 

Table 1: Inmaculada Project, Angela Vein Deposit - Mineral Resource Estimate -- February 24, 2011.

Resource Estimate
(g/t gold Equiv)
  Tonnes   Gold Grade (g/t)   Silver Grade (g/t) 100% Project Contained Ounces
Gold   Silver   Gold Equivalent   Silver Equivalent
Measured 4.2   698,000   6.0   153 135,000   3,420,000         192,000    11,520,000
3.0   941,000   5.1   136 155,000   4,110,000   223,500    13,410,000
1.6   1,094,000   4.7   125 164,000   4,410,000         237,500    14,250,000
Indicated 4.2   2,951,000   6.1   226 578,000   21,450,000         935,500    56,130,000
3.0   3,806,000   5.2   198 640,000   24,210,000   1,043,500    62,610,000
1.6   4,518,000   4.7   177 676,000   25,700,000      1,104,333    66,260,000
Measured and Indicated 4.2   3,649,000   6.1   212  713,000   24,880,000      1,127,667    67,660,000
3.0   4,747,000   5.2   186  795,000   28,320,000   1,267,000    76,020,000
1.6   5,612,000   4.7   167 840,000    30,110,000      1,341,833    80,510,000
Inferred 4.2   1,998,000   7.4   295  473,000   18,950,000         788,833    47,330,000
3.0   2,648,000   6.1   247  521,000   21,030,000   871,500    52,290,000
1.6   3,553,000   5.0   199 568,000    22,770,000         947,500    56,850,000

1. Resources are shown on a 100% project basis. IMZ owns a 40% interest.

2. Metal prices used are US$15/oz for silver and US$900/oz for gold.

3. An overall average bulk density of 2.51 tonnes per cubic metre has been used for the tonnage estimation.

4. Gold equivalent grade is calculated at a silver:gold ratio of 60:1, using metallurgical recoveries of 88% for gold and 83% for silver and metal prices as stated in Note 2.

5. The resources are reported at a 3 g/t gold equivalent cut-off grade. This case is shown in bold text in the Table above.

6. The estimated mineral resources are not mineral reserves and do not have demonstrated economic viability.

7. Numbers have been rounded in all categories to reflect the precision of the estimates.

8. The mineral resources were estimated by Hochschild using the ordinary kriging capability of MineSite software to estimate metal grades for the main vein body and inverse distance to the power of three for the peripheral veins. A block size of 10m by 5m by 10m in size was used and outlier high grades were top-cut to 30 g/t for gold and 860 g/t for silver.

The Inmaculada mineral resource estimate has been estimated by Hochschild and classified in accordance with CIM guidelines and reviewed by IMZ's Qualified Person Nick Appleyard and the estimate has an effective date of February 24, 2011. The mineral resource estimate is based on the results of 240 core drill holes for approximately 71,000 meters ("m") of drilling, which have defined a strike length to the Angela Vein mineralization of approximately 2 Km (which is still open to the northeast) and a vertical extent of over 300m.

On December 28, 2010, IMZ signed a definitive agreement with Hochschild to fast track production at the Inmaculada project, whereby Hochschild have committed to building a mining operation at Inmaculada with a process capacity of 3,000 tonnes per day (unless the parties agree that such capacity is not optimal) by December 2013, subject to any unforeseen delays under defined "force majeure" conditions. Hochschild will provide 100% of the initial $100 million of funding required to complete a feasibility study and the planning, development and construction of a mining operation at Inmaculada. Any subsequent expenditures will be funded 60% by Hochschild and 40% by IMZ.

Resource Estimation Methodology

The resource estimation was constrained using a 1.6 g/t gold equivalent wireframe to outline the mineralized zone. The wireframe was constructed from cross-sectional interpretation of the Angela Vein deposit by Hochschild geologists and included splays (or branches) from the main vein. A search ellipse with a radius of 75m, sub-divided into quadrants, was then used to interpolate grades based on 1m downhole composites, into the 10m by 5m by 10m blocks that were aligned with the strike of the Angela vein, using the ordinary kriging capability of MineSite software. 

Resources were classified in the Measured Category for all blocks that met two criteria: 1) at least one sample within 25m (one third of the variogram range); 2) samples from at least four quadrants. Resources were classified in the Indicated category when at least two samples were within 50m (two thirds of the variogram range). Resources for all other blocks within the range of the variogram were classified in the Inferred category.

About International Minerals

International Minerals is a silver-gold producer, explorer and developer with silver-gold production from its 40%-owned Pallancata Mine in Peru, which is operated by Hochschild and is one of the top-5 primary silver mines in the world. Production at Pallancata in calendar year 2010 was approximately 10.1 million ounces of silver and 36,000 ounces of gold (on a 100% project basis).

In addition to the Pallancata Mine and the 40% interest in the Inmaculada gold-silver project, IMZ also owns a majority or 100% ownership interests in development stage gold projects in Nevada (Goldfield and Converse) and Ecuador (Rio Blanco and Gaby). IMZ also holds a 3% net smelter return ("NSR") royalty from Barrick Gold's Ruby Hill gold mine in Nevada, which produced approximately 80,000 gold ounces in 2010.

IMZ is listed on the Toronto Stock Exchange (since 1994) and the Swiss Stock Exchange (since 2002). The technical information reported in this news release was reviewed by IMZ's Qualified Person, VP Corporate Development, Nick Appleyard.

Hochschild Mining plc does not accept any responsibility for the adequacy or inadequacy of the disclosure made in this news release and any such responsibility is hereby disclaimed in all respects.

Cautionary Statement:

Some of the statements contained in this release are "forward-looking statements" within the meaning of Canadian Securities law requirements. Such forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements to differ materially from the anticipated results, performance or achievements expressed or implied by such forward-looking statements. Forward-looking statements in this release include statements regarding mineral resource estimates. Factors that could cause actual results to differ materially from anticipated results include risks and uncertainties such as: risks of estimating mineral resources and other risks and uncertainties detailed in the Company's Renewal Annual Information Form for the year ended June 30, 2010, which is available at under the Company's name. The Company disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

Contact Information

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