Subscribe for Updates:

Enter your email below to receive email updates

RSS Feed:

Press Releases

Jun 02, 2009
Mindoro Reports 1.94 Grams per Tonne Gold Over an Aggregate 26 Meters From Underground Sampling at Extension of American Tunnels
EDMONTON, Alberta; June 2, 2009, Mindoro Resources Ltd. (TSXV: MIO; Frankfurt: WKN 906167), has reported results from underground sampling of active small-scale artisanal gold workings, known as Roque Mine, in the north part of the American Tunnels prospect, Agata Project. The Roque Mine consists of a shaft extending to a depth of 16 meters, with drifts and stopes extending outward in several directions.

Continuous rock chip samples were taken from all accessible drifts and stopes. These assayed 1.94 grams per tonne (g/t) gold over an aggregate length of 26 meters, including 2.41 g/t over two meters, 3.15 g/t over two meters, and 3.11 g/t over 1.5 meters; full results are reported in the table below. Mineralization is open in all directions. The Roque Mine is 215 meters north of the American Tunnels copper-gold area. The results are a further indication of the widespread gold mineralization within the American Tunnels trend and its likely extension under surrounding ultra-mafic cover rocks.

An initial test of 6 to 8 drill holes totaling 1,200 to 1,500 meters, planned to commence in late June, is designed to test both gold mineralization and a porphyry copper-gold target to shallow depths. Work at American Tunnels is continuing to evaluate and prioritize additional drill targets. While drilling will initially focus on American Tunnels, the prospect is just part of the highly prospective six kilometre mineralization trend at Agata.


Sample Number

Length of Sample (m)

Au g/t

 Rock Chip Sample Location

SU 07401



East wall of  N-S stope

SU 07402



North wall of E-W stope

SU 07403



North wall NW decline.

SU 07404



Roof of NW decline.

SU 07405



Floor NW stope.

SU 07406



North wall of winze W stope.

SU 07407



East wall of N-S drift.

SU 07408



East wall of  N-S drift (continuation of SU 07407).

SU 07409



Roofing of  NW drift.

SU 07410



NW decline (continuation of SU 07409).

SU 07411



West wall of NE stope.

SU 07412



East wall of NE stope.


American Tunnels is a small erosional window through ultra-mafic cap rocks within a six kilometre trend of strong IP chargeability anomalies associated with extensive alteration, geochemical anomalies, and abundant gold and copper-gold showings. There are over 100 shallow artisanal mines and workings within the trend, but mineralization is mostly obscured by ultra-mafic cap rock of variable thickness.


Both gold and porphyry copper-gold mineralization targets are recognized at American Tunnels:

Gold Mineralization

The American Tunnels area has a long and continuing history of small-scale, artisanal gold mining. Gold is mined from a honeycombing of shallow (5 to 20 meters deep) underground workings within an area of about 200 meters by 225 meters. Free gold is also present in streams draining ultramafic cap rocks up to 1,200 meters north of American Tunnels; possibly reflecting an extension of the gold mineralization trend. There are also dozens of artisanal gold workings within several other localized erosional windows south of American Tunnels. The miners follow narrow high-grade veins, vein stock-works, shear zones and fracture-filled zones near the top of an intrusive complex.

Bonanza gold zones were not unusual during the high-grading in the 1980's and 1990's, and are still encountered. Artisanal miners provided some grade information, of varying degrees of reliability, from the more recent workings. Unfortunately, most information has been lost for ever. In general, recovered gold grades are reportedly in a wide range from 2 g/t gold to as high as plus 1,000 g/t gold.

In oxidized, near-surface material, the gold is supergene-enriched and higher grade than in un-oxidized material below. The gold is almost always associated with sulphide-bearing diorite and monzonite intrusives. The sulphide is mostly pyrite, in places with associated bornite and chalcopyrite.

Porphyry Copper-Gold Related

During 2007 and most of 2008, artisanal miners were also actively mining high-grade copper from shallow workings over an area of about 50 meters by 50 meters. The copper ore was mined by manual methods and ore grading 5 percent to 15 percent copper sold to local buyers to be sent to China for processing. Eight underground workings were being mined for copper and about 22 for gold. Recently, lower copper prices have terminated the copper mining. Artisanal gold mining activity has accelerated.

American Tunnels is characterized by an IP chargeability anomaly extending over 800 meters by 300 meters, with associated resistivity and magnetic anomalies. The chargeability anomaly here is relatively shallow-sourced compared to the remainder of the six kilometer anomaly trend at Agata. Underground sampling of the copper workings gave high copper values, associated in places with high gold and molybdenum values (see news release dated Nov.17, 2008). Mineralization is at the top of multi-phase intrusives, on the cusp of a shallow IP chargeability anomaly that "daylights". The copper 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. A cross section showing the location of underground workings relative to the IP chargeability anomaly, together with a map showing the Agata IP chargeability anomalies in plan view, appeared in a news release November 17, 2008.

Mineralization is principally within late, fractionated 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 alteration assemblages of chlorite, epidote, actinolite, biotite, sericite, magnetite and albite. Copper minerals are chalcopyrite and bornite. These features, as well as the high molybdenum values, are consistent with a porphyry copper-gold setting.

Tony Climie, P.Geol, is the Qualified Person responsible for monitoring the supervision and quality control of Mindoro's programs and who has reviewed and verified the technical information contained in this news release. Since there is visible gold, screen fire assaying was performed on all samples by McPhar Laboratories. The samples were crushed and then reduced to 1 kilogram prior to fine pulverizing. After fine pulverizing, the samples were screened to 200 mesh, resulting in +200 mesh and -200 mesh fractions; the -200 mesh fraction was further split. 50-gram fire assays with AAS finish were carried out over the +200 mesh and the two -200 mesh fractions; the average assay for the two -200 mesh splits was taken. The gold values for the +200 mesh and -200 mesh fractions were then computed using standard calculations. Check assays were carried out by Intertek Labs, with samples showing a close correlation.


Mindoro is a Tier 1 Issuer trading on the TSX Venture Exchange (MIO) and the Frankfurt Stock Exchange (WKN 906167). Mindoro is focused on gold, copper-gold and nickel exploration in the Philippines with a strategy of advancing early stage opportunities to production or joint venture. Mindoro has NI 43-101 resource estimates on its Agata North nickel-cobalt project and on both its Lobo (SWB) and Archangel (Kay Tanda) gold-silver projects. Mindoro has also identified 22 porphyry copper-gold prospects and has a joint venture agreement with Gold Fields covering three of its Batangas projects. Avocet Mining PLC is carrying out due diligence drilling on the Kay Tanda gold-silver resource also in Batangas.

Mindoro is well positioned to capitalize on the rising global demand for precious and base metals in 2009 with drilling planned on gold and copper-gold projects funded by Avocet and Gold Fields, and drilling on the American Tunnels gold/copper-gold project. Additional 2009 objectives include finalizing one to two additional joint venture arrangements on Mindoro's porphyry copper-gold prospects at Pan de Azucar and Surigao and identifying a suitable partner to fund development of the significant Agata North nickel-cobalt resource.

For further information, contact:


Mindoro Resources Ltd.

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

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

Robert Sarcher:
Tel. 49 821 6089051

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 and the uncertainty of the availability of capital). 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 Jul 8, 2009, Gold Fields Provides Update on Progress on the Batangas Joint Ventures

You can view the Previous Press Releases item: Tue May 26, 2009, Mindoro 2008 Annual Report Available

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