Subscribe for Updates:
Enter your email below to receive email updates
Oct 09, 2007
Calo Drilling Encounters Porphyry-Mineralized Clasts / Fragments
EDMONTON, Alberta; October 9, 2007 - Mindoro Resources Ltd. (TSXV: MIO; Frankfurt: WKN 906167) is pleased to advise that it has intersected transported clasts (rock fragments) of porphyry copper mineralization in a lithic tuff in drill hole 7 on the Calo porphyry copper-gold prospect, located within the Batangas projects, Luzon Island, the Philippines. The potassic-altered diorite and chlorite-clay altered volcanic clasts contain up to one percent chalcopyrite and are believed to have been transported a relatively short distance from their source. This new porphyry mineralization occurrence, along with Freeport McMoRan's Tayson porphyry copper-gold prospect eight kilometers to the north, and Mindoro's Pica porphyry copper-gold prospect four kilometers to the south, are confirming the potential of the very large Calo target area for a cluster of porphyry copper-gold deposits.
Drill hole 7 was the final hole of a scout drilling program on the Calo target. Previous results were reported in news releases dated March 28, July 4 and August 25, 2007. Hole 7 was drilled on line 12,000N to test a strong chargeability anomaly of 50 to 100 msecs (see the accompanying map). It is near a major north-south graben fault along Lobo River, which has down-dropped the Talahib Volcanics, the regional host to mineralization. The graben was filled with younger cover volcaniclastics and sediments which range in thickness from zero in the western part of the Calo prospect, to about 580 meters thick near the Lobo River Fault; thus forming a wedge of cover rocks that thickens towards the Lobo River (see the accompanying interpreted cross section).
Drill hole 7 intersected 580 meters of cover volcanics and volcaniclastics and then went into a lithic tuff at the top of the Talahib Volcanics. Clasts of diorite intruding volcanics were found in the tuff (which can be considered a kind of scree deposit or local lahar). Petrology by Mindoro's independent petrology consultant describes strong potassic (secondary biotite to 20%), clay (to 10%) and chlorite (to 10%) alteration and silicification (to 25%), with from trace to 1% chalcopyrite (copper-iron sulphide) and up to 3% hydrothermal magnetite in clasts of the diorite and volcanics.
These clasts are interpreted to be derived from the core of a porphyry copper-gold system, where there is a diatreme about 700 meters to the west. Diatremes are commonly associated with porphyry copper-gold deposits in Southeast Asian island arcs. Anomalous soil values of up to 150 parts per million copper are noted in proximity to the diatreme. Cover thickness near the diatreme is thin. Drill hole 7 passed from the lithic tuff into propylitic-altered andesitic volcanics at 710 meters.
Calo drill hole 6 had previously been completed at a depth of 358 meters, three kilometers south of drill hole 7. Cover volcanics were intersected to 296 meters, and below these, the Talahib Volcanics; generally with weak alteration, but containing structurally-controlled zones of argillic alteration and pyritization (to 5% pyrite). No significant mineralization was encountered in this hole.
With the completion of the current phase of drilling, all results to date will be carefully evaluated to assist in vectoring in to the mineralization center in a second, more focused, round of drilling. Clearly, the diatreme area will be one of the priority areas for that more detailed drilling.
Mindoro's Batangas projects cover about 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.
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 four 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 is typically associated with porphyry copper deposits. The copper has been transported in by ground waters from an unknown source, and quite possibly from the chargeability anomaly below.
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). In addition to advancing the Agata nickel laterite project towards production, Mindoro is carrying out a major resource delineation program on its Kay Tanda gold-silver project. The company has also identified 22 porphyry copper-gold prospects in the Philippines and has an aggressive strategy of drilling multiple targets in 2007/2008.
FOR FURTHER INFORMATION, CONTACT:
Executive Vice President
Ascenta Capital Partners Inc.
Toll Free: 1.866.684.4209 ext. 228
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: Thu Oct 11, 2007, Update on Philippine Projects
You can view the Previous Press Releases item: Mon Oct 1, 2007, Mindoro Raises $4 Million in Final Tranche of Private Placement
You can return to the main Press Releases page, or press the Back button on your browser.