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Jul 04, 2007
Calo Drilling Encounters Porphyry Related Alteration
EDMONTON, Alberta; July 4, 2007 - Mindoro Resources Ltd. (TSXV: MIO; Frankfurt: WKN 906167) today reported results of a further three reconnaissance drill holes CL-3 to CL-5 from its Calo porphyry copper-gold prospect, located within Mindoro's Batangas projects, Luzon Island, the Philippines. The three holes were drilled over a distance of one kilometer as a fence along section 9100N. All holes passed through porphyry-related advanced argillic lithocap, argillic alteration, and into inner propylitic alteration below. Structurally-controlled zones of phyllic alteration were encountered in the two easternmost holes (CL-4 and CL-5), with increasing intensity of porphyry-related alteration to the east. Pyrite content ranges from 5 to 15 percent, which probably explains the chargeability anomaly and is interpreted as the pyrite halo of the porphyry system. Anomalous gold, copper, silver, arsenic, zinc and lead were encountered in all holes. Hole CL-6, a further 675 meter step out to grid east has commenced. The map accompanying this release shows the location of all drill holes.

Tony Climie, Mindoro's President commented, "Although we have not yet located the mineralized core of the porphyry copper-gold system within what is a very large target area, we are pleased to note that all holes drilled so far, over a distance of 3.5 kilometers, have intersected porphyry-related alteration. Upon completion of holes six and seven, we will evaluate all results to date to assist us in vectoring in to the mineralization center in a second, more focused round of drilling."

CL-3 (9083N/ 10000E)
CL-3 (3300 azimuth/ 75° inclination) was drilled to test the advanced argillic zone in the western part of the Calo prospect. It is coincident with a moderate chargeability (20-30 msec) anomaly. The hole intersected advanced argillic alteration down to 16 meters and then porphyritic andesite with propylitic alteration down to hole bottom at 226 meters. Minor base metal sulfides consisting of galena, chalcopyrite and sphalerite are present as veinlets and as fracture fills within the propylitized andesite, plus very fine pyrite (to five percent). The advanced argillic alteration encountered in CL-3 is interpreted to be related to a porphyry system.

CL-4 (9000N/ 10450E)
CL-4 (150° azimuth/ 70° inclination) was situated in an argillic altered zone with a coincident moderate chargeability (20-30 msec) anomaly. From collar to 60 meters, the hole intersected argillic to intermediate argillic altered andesitic flows and lapilli tuffs, with gypsum veins and minor pyrite and chalcopyrite disseminations. From 60 meters to hole bottom at 360 meters, it intersected propylitic-altered porphyritic andesite. Weak sericite and epidote alteration occur within the propylitized zone, suggesting progressing intensity of porphyry-related alteration towards grid east. Pyrite content averages 10 percent.

CL-5 (9000N/10975E)
CL-5 (150° azimuth/ 75° inclination) was drilled in argillic-altered porphyritic andesite tuff with a coincident moderate to high chargeability anomaly (30-50 msec). The hole intersected weakly altered andesitic tuff down to 46 meters, then argillic to intermediate argillic-altered intercalated porphyritic andesite, lithic tuff and andesitic lapilli tuff with gypsum and anhydrite veins down to 250 meters depth. A narrow zone of vuggy silica zone was intersected from 61 to 65 meters with low grade gold mineralization (1.18 grams per tonne gold over 1.2 meters). High-temperature propylitic altered porphyritic andesite was then intersected to hole bottom at 456 meters. A narrow zone of structurally controlled phyllic alteration overprints the propylitic alteration.

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 a NI 43-101 compliant resource estimate is in progress, as well as the Calo and El Paso porphyry copper-gold targets. Phelps Dodge's (now Freeport McMoRan) Taysan porphyry copper-gold deposit is approximately nine kilometers north of Calo.

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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 - which 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 two 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 breccia 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 and expansion drilling on the Kay Tanda epithermal gold-silver prospect where a NI 43-101 compliant resource estimate is in progress; reconnaissance drilling on the Calo porphyry copper-gold prospect; and advancing a significant nickel laterite prospect towards early 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: Fri Jul 6, 2007, Final Results from High Grade Hole KTDH-20 at Kay Tanda

You can view the Previous Press Releases item: Tue Jul 3, 2007, Further Positive Drill Results from Agata Nickel Laterite

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