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Press Releases

Mar 28, 2007
Calo Drilling Encounters Porphyry Related Alteration

EDMONTON, Alberta; March 28, 2007 - Mindoro Resources Ltd. (TSXV: MIO; Frankfurt: WKN 906167) today reported results of the first two reconnaissance drill holes from its Calo porphyry copper-gold prospect, located within Mindoro's Batangas projects, Luzon Island, the Philippines. Both holes encountered hydrothermal alteration, consistent with the outer pyritic halo of a porphyry copper-gold system. A third hole, a further two kilometers distant from the first two holes, is commencing and is targeting an area of advanced argillic alteration, with associated copper showings. Due to the very large size of the target, this initial program of 3,500 meters in six drill holes will be widely-spaced; up to two kilometers apart.

Tony Climie, President of Mindoro, commented, "We are pleased with these results, as the first two holes ever drilled into Calo, and two kilometers apart, both encountered porphyry-related alteration. These results support our surface indications of a large porphyry copper-gold system. We will continue our program of wide spaced drilling with the objective of vectoring into the mineralization centers."

Hole Cl-1 was drilled in the southern part of the target and intersected loosely consolidated young cover sediments and pyroclastic materials from collar to 162 m depth. Volcanic breccias, flows and tuffs were then intersected to hole bottom at 502 meters. Zones of opaline silicification, pyritization and clay alteration were encountered, with intensity of hydrothermal alteration increasing with depth. Pyrite content [up to 15 per cent] and fracture frequency both increase towards hole bottom. Anomalous zinc [to 960 parts per million] and copper [to 200 parts per million], gold and arsenic are associated with the pyritic zones. The hole was terminated prematurely due to operational problems.

Hole Cl-2 was drilled two kilometers to the north. It intersected volcanic breccias, flow and tuffs, with zones of opaline and chalcedonic silica alteration, chloritization and barite. Sericite alteration occurs in structural zones. Geochemical results have not yet been received.

click to enlarge

The alteration is strongest in the more permeable volcanics units, indicating lateral flow of hydrothermal fluids. The opaline and chalcedonic silica and barite are interpreted to be associated with epithermal mineralization events, both low and high sulphidation, which frequently overprint porphyry copper-gold systems in the Philippines. The high temperature sericite alteration in Cl-2 is interpreted as porphyry-related. The high pyrite contents are consistent with the outer pyrite halo associated with porphyry copper-gold systems.

Hole Cl-3 is commencing in a further two kilometer step-out and will be drilled in an area of advanced argillic alteration on the western part of Calo. Copper and copper-gold showings are associated with the argillic alteration, and skarn copper mineralization was located nearby in newly acquired ground not yet covered by geophysical [IP] surveys.

Mindoro's Batangas projects cover over 30,000 hectares in a well-mineralized copper-gold belt and include the Kay Tanda epithermal gold-silver prospect, where resource delineation is in progress, and the promising Calo, El Paso and Archangel porphyry copper-gold prospects, each with multiple targets. Phelps Dodge's [now Freeport McMoRan] Taysan porphyry copper-gold deposit is approximately nine kilometers north of Calo.


As described in Mindoro's November 30, 2006, press release, the Company has defined a cluster of unusually large Induced Polarization anomalies at Calo, with extremely high chargeability readings of up to 100 msecs against a background of 6-8 msecs. Much of the anomaly cluster, which is at least three kilometers by six kilometers in extent, is covered by younger rocks; with the source, therefore, being obscured. The anomalies are interpreted as related to porphyry-copper-gold mineralization, possibly with multiple mineralization centers. High-sulphidation epithermal copper-gold showings, along with advanced argillic alteration, are usually indicative of proximity to porphyry mineralization in the Philippines, as well as diatreme breccias and porphyry-type alteration, occur around the margins of the chargeability anomalies, and in erosional windows.

Porphyry copper-gold mineralization has already been drill-intersected by Mindoro on the far-eastern margin of Calo, where Pica drill hole 2 intersected 213 meters of 0.18 percent copper and 0.30 grams per tonne gold below a cap of advanced argillic alteration. In another area, young volcanic conglomerates above the chargeability anomaly contain exotic copper mineralization which has moved in from an unknown source, and quite possibly from the chargeability anomaly below. Two trenches in this showing gave 2.62 percent copper over 30 meters, and 2.17 percent copper over 20 meters.

Programs are carried out under the supervision of Tony Climie, P.Geol., who is a qualified person as defined by National Instrument 43-101.


Mindoro is a Tier 1 Issuer trading on the TSX Venture Exchange (MIO) and the Frankfurt Stock Exchange (WKN 906167). The Company is carrying out three major drill programs: resource delineation drilling on the Kay Tanda epithermal gold-silver prospect, reconnaissance drilling on the Calo porphyry copper-gold prospect, and advancing a significant nickel laterite prospect towards production; in addition to holding another 22 identified porphyry copper-gold prospects in the Philippines.


Penny Gould
Executive Vice President
Phone: 780.413.8187

Trent Dahl
Ascenta Capital Partners Inc.
Phone: 604.628.5800
Toll Free: 1.866.684.4209 ext. 228

Richard Mayr
Argentuminvest GmbH
Phone: +49.9421.785250
Fax: +49.9421.785255

The TSX Venture Exchange has not reviewed and does not accept responsibility for the adequacy or accuracy of this release.

This release may contain forward-looking statements including management's assessments of future plans and operations, and expectations of future production. These statements are based on current expectations that involve a number of risks and uncertainties, which could cause actual results to differ materially from those anticipated. These risks include, but are not limited to, the risks associated with the mining and exploration industry (e.g. operational risks in development, exploration and production; delays or changes in plans with respect to exploration or development projects or capital expenditures; the uncertainty of reserve estimates; the uncertainty of estimates and projections relating to production). The assumptions used in the preparation of such statements, although considered reasonable at the time of preparation, may prove to be imprecise and, as such, undue reliance should not be placed on forward-looking statements.

You can view the Next Press Releases item: Wed Apr 4, 2007, Further Drill Results Reported from Kay Tanda and Geostatistical Resource Estimate Commissioned

You can view the Previous Press Releases item: Wed Mar 21, 2007, Excellent Metallurgical Test Results From Kay Tanda

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