Subscribe for Updates:

Enter your email below to receive email updates

RSS Feed:

Press Releases

Nov 17, 2008
Extensive Copper Mineralization From Mindoro's American Tunnels Prospect
EDMONTON, Alberta; Nov. 17, 2008 - Mindoro Resources Ltd. (TSXV: MIO; Frankfurt: WKN 906167) is pleased to report results of detailed underground mapping and sampling carried out within artisanal small scale mine workings on the American Tunnels copper-gold prospect, Agata Project, Philippines. Extensive copper mineralization, associated in places with high gold and molybdenum values, was encountered throughout most of the underground workings. The mineralization is at the top of multi-phase intrusives, on the cusp of a strong Induced Polarization (IP) anomaly. Mineralization is interpreted as a high-grade, late-stage, concentration at the upper contact of the intrusive stocks and dykes, and derived from porphyry copper-gold mineralization below. American Tunnels is in the center of a six kilometer long cluster of IP anomalies and at a point where the IP anomaly is shallowest; essentially at surface. Therefore it seems likely the deeper IP anomalies also reflect copper-gold mineralization.

In a news release dated May 12, 2008, Mindoro reported that high-grade copper mineralization was being mined on a small scale by artisanal miners at American Tunnels in shallow workings over an area of about 150 m by 50 m. The copper ore is being mined by manual methods and ore grading 5 percent to 15 percent copper is sold to local buyers to be sent to China for processing. Up to seven underground workings were being mined. With the recent decline in copper prices this has now reduced to three mine workings. The small scale mining does not impact on Mindoro's plans to evaluate and advance the porphyry copper-gold potential of the prospective trend, and the local miners will likely be integrated into the Company's future programs.

Mindoro has carried out detailed underground mapping and sampling of part of the American Tunnels area over the past six months. Samples were taken along the walls of mined out areas. The accompanying map shows results of the sampling and copper values plotted against rock type (35 samples). The copper values are color-coded to illustrate the extensive distribution of copper mineralization. It is open in several directions. The more significant channel and rock chip results are as follows (all results appear on the accompanying map):


Copper %

Gold g/t

Silver g/t

Molybdenum ppm

Sample Type
























Rock chip


















Vertical rock chip






Rock chip






Rock chip






Rock chip

A 20 centimeter sample from a vein grading 3.12 percent copper, 88.64 g/t gold, 29.2 g/t silver and 932 ppm molybdenum may represent epithermal gold-silver mineralization telescoped into the porphyry-related mineralization. Eleven other workings at American Tunnels are being actively mined for epithermal gold (an overprinting event).

Click to Enlarge

Click to Enlarge

Click to Enlarge

Mapping by Mindoro and petrology work by an independent petrologist indicate mineralization is principally within monzonite phases of a syenite, monzonite, monzodiorite and diorite intrusive complex of dykes, sills, and small stocks intruding ultramafic rocks. Mineralization is associated with complex assemblages of chlorite, epidote, actinolite, biotite, sericite, magnetite and albite alteration. Copper minerals are chalcopyrite and bornite. These features, as well as the high molybdenum values, are consistent with a porphyry copper-gold setting.

The American Tunnels prospect, characterized by a strong IP chargeability anomaly extending over 800 meters by 300 meters, is capped by a resistivity anomaly and coincident with a magnetic anomaly. The accompanying cross section shows the location of underground workings near the top of the IP anomaly. Extensive copper, gold and zinc soil anomalies are associated. The IP chargeability anomaly is part of a cluster of strong chargeability anomalies extending over at least six kilometers of strike through the Agata Project, which are associated with intersections of splays of the Philippine Fault and cross-cutting faults (see accompanying plan of part of the Agata Project IP cluster showing the location of the American Tunnels anomaly). In 2005, four drill holes in the north and south parts of the IP trend were lost due to technical problem in bad ground, and did not reach target. In a remarkable geological coincidence, extensive nickel laterite mineralization is juxtaposed in close proximity to the porphyry copper-gold prospects, and is itself the subject of intensive economic evaluation by Mindoro.

The American Tunnels is an as yet untested high-priority drill target for both epithermal gold, and especially, for porphyry copper-gold mineralization. The extent of alteration, abundance and strength of copper-gold showings, and of the associated IP anomalies, indicate a source of considerable potential interest.

Programs are carried out under the supervision of Tony Climie, P.Geol., president of Mindoro, who is a qualified person as defined by National Instrument 43-101. Sample preparation and assaying is performed by McPhar Laboratory of Manila, an ISO 9001/2000 accredited laboratory. Gold assays were by 50 gm fire assay fusion; where gold assays greater than 3 ppm were by gravimetric finish and by AAS where the gold values were less than that threshold. Silver, copper and molybdenum were determined by AAS after an HCl-HNO3-HClO4 digest. Normal Quality Control and Quality Assurance procedures are being carried out, using a system of duplicate samples. MRL has also conducted assays verification by using standard samples and re-assaying of field, coarse and pulp duplicates.


Mindoro is a Tier 1 Issuer trading on the TSX Venture Exchange (MIO) and the Frankfurt Stock Exchange (WKN 906167). Mindoro is focused on building shareholder value through diverse resource exploration in the Philippines and by advancing early stage opportunities to production or joint venture. In keeping with this multi-commodity strategy, Mindoro has announced an initial NI 43-101 compliant nickel-iron-cobalt resource estimate on its Agata North project, where resource expansion drilling has recently been completed. A final resource estimate for Agata will be released in late November. NI 43-101 compliant mineral resource estimates have also been released for the Kay Tanda and SW Breccia gold and silver projects. Mindoro has also identified more than 20 porphyry copper-gold prospects on its Batangas, Pan de Azucar and Surigao projects. Mindoro recently entered into joint venture arrangements with Gold Fields and Avocet Mining PLC on its Batangas Projects.
For further information, contact:


Mindoro Resources Ltd.

Penny Gould, President:
Tel: 780.413.8187
Toll Free: 1.877.413.8187

Renmark Financial Communications Inc.
Barbara Komorowski:
Jason Roy:
Tel: 514.939.3989
Fax: 514.939.3717


Argentuminvest GmbH

Richard H. Mayr:
Tel: +49.9421.568899-0
Fax: +49.9421.568899-4

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: Tue Nov 25, 2008, Valderama Massive Pyritic Sulphide Prospect to be Evaluated as a Stand-Alone Sulphuric Acid Producer

You can view the Previous Press Releases item: Mon Nov 10, 2008, Mindoro's Batangas Joint Ventures On Track For 2009

You can return to the main Press Releases page, or press the Back button on your browser.