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Jan 28, 1999
Further Encouraging Exploration Results Tiris Project, Sumatra, Indonesia
Presence of a very large epithermal gold system confirmed, extending over more than 5.8 by 2.5 kilometres, with multiple zones of widely-dispersed, breccia and stockwork gold-silver mineralization which are interpreted to coalesce to bonanza-style vein systems at depth.

Tony Climie, P.Geol., President of Mindoro Resources Ltd. ("Mindoro"), announces further encouraging Phase 2 exploration results for the Tiris Project, where an extensive epithermal gold system has been identified. Preliminary results were announced November 19, 1998.

Phase 2 focussed on detailed follow-up of the Harimau Prospect and consisted of geochemical and geological surveys, prospecting, airborne geophysics, and a structural interpretation using satellite synthetic aperture radar (SAR). All geochemical analytical work was performed utilizing standard procedures by Intertek Testing Services/Bondar Clegg in Jakarta, Indonesia, an internationally-accredited laboratory.

Most Phase 2 results have now been received. These confirm the presence of a very large low-sulphidation epithermal gold system that extends well beyond the present Harimau survey grid of 5.8 by 2.5 kilometres. As previously reported, three large soil gold anomalies, termed the Selatan, Barat and Utara Zones, have been defined in overburden-covered areas between streams containing intensely anomalous gold and silver values in sediments. Follow-up auger sampling, soil sampling, geological mapping and rock sampling were carried out on the Selatan and Barat Zones, and elsewhere on the encompassing Harimau Prospect.

Although primary gold mineralization remains the principal target, initial indications of coarse gold in soils (including panned grains to 0.2 mm) and historical Dutch sluicing suggested potential for a near-surface oxide resource on the Selatan Zone. This oxide potential was tested by 14 shallow auger holes on 400 by 400 metre spacings to a maximum of 2.7 metres depth, with 2 to 4 samples per hole. Results for individual samples ranged from 10 to 1,067 parts per billion (ppb) gold, while the weighted average for all holes was 193 ppb/2.3 metres. Little potential is seen for a shallow economic oxide resource on the Selatan Zone and work will continue to focus on primary mineralization potential.

An additional 350 soil samples were analyzed from the Barat Zone. Values ranged from less than 5 to 1,225 ppb gold and averaged 29 ppb. These results have extended the Barat Zone 300 metres to the southeast where it now merges with the Selatan Zone (see map).

Geology of the Harimau Prospect consists of a pile of variably-welded dacitic airfall tuffs and lake sediments intruded by andesitic porphyries and rhyolite dykes. Pervasive and widespread hydrothermal alteration extends well beyond the present grid. Early propylitic and phyllic assemblages are overprinted by strong quartz-sericite-adularia alteration accompanied by stockworking and hydrothermal brecciation with associated pyrite and gold mineralization. Geological mapping defined numerous sub-parallel, northeast-trending faults, also evident in the SAR and airborne magnetics. At surface, these faults are characterized by broad, continuous zones of quartz flooding accompanied by up to 10% pyrite.

Rock sampling, although restricted to outcrops and boulders in streams due to lack of surface outcrop, indicates widespread gold mineralization. For all programs to date, a total of 181 samples have been collected from the Harimau Prospect. Values range from less than 0.005 to 10.6 grams per tonne (g/t) gold, and average 0.37 g/t. Seventeen samples have values greater than 1 g/t gold (range of 1.04 to 10.6 g/t and average of 3.35 g/t gold) and are well-distributed across the prospect (see map). Twelve samples are from float (average is 3.51 g/t gold) and five from outcrop (average is 3.43 g/t gold). Twenty-seven samples also contain greater than 10 g/t silver (including 6 over 100 g/t with a maximum of 520 g/t).

Eight widely-dispersed rock samples were analyzed also for elements characteristic of high levels of epithermal gold systems. Arsenic values range from 2 to 74 parts per million (ppm), antimony from less than 0.02 to 21.3 ppm and tellurium from 0.1 to 77 ppm. The high ranges are strongly anomalous for all elements.

Gold grades in excess of 1 g/t are widely dispersed across the Harimau Prospect but, due to lack of outcrop, the nature and significance of the mineralization are not yet understood. Geological and geochemical evidence suggests that only the uppermost parts of the gold system are exposed by erosion. The quartz-flooded faults are interpreted to have acted as pathways for mineralizing fluids. Near-surface mineralization became widely dispersed as a multi-kilometre halo of relatively low grade (below 1 g/t gold) within the permeable air fall tuffs. Within this, higher grades (multi-g/t gold) are associated with better developed breccias, stockworks and zones of quartz-flooding. These high-level structures are considered likely to merge and coalesce at relatively shallow depth into larger vein systems with good potential for bonanza-type grades. A second potential mineralization setting is for stratabound or ponded mineralization at boundaries between contrasting permeabilities, such as welded/unwelded tuffs and intrusive contacts.

Given the very large size and intensity of the Harimau epithermal system, and the widespread occurrence of gold mineralization, Mindoro management considers the prospect has significant potential for multiple zones of economic gold-silver mineralization.

Proposed work for the next dry season, commencing about May, includes geophysical surveys, further definition of structural and lithologic targets, and drill-testing of targets as defined. Given the size of the entire Harimau gold system, and magnitude of required exploration, Mindoro is considering acquiring a senior partner for the project. Several unsolicited expressions of interest have already been received and Mindoro is currently initiating discussions with several major companies.

Mindoro is a Canadian mineral exploration company focussing on gold and gold-copper exploration in the Asia Pacific region and operates projects in the Philippines and Indonesia. Copies of the attached map may be obtained from Mindoro's office or viewed in colour at the Company's website.

For more information, contact:
Rodney Orr, P.Geo., Senior V.P. or Penny Gould, V.P. Corp. Development
Phone: (780) 413-8187
Fax: (780) 426-2716

The Alberta Stock Exchange has neither approved nor disapproved the information contained herein.

You can view the Next Press Releases item: Thu May 13, 1999, Update on Mindoro Resources Ltd. Activities

You can view the Previous Press Releases item: Thu Nov 19, 1998, Harimau Prospect - Phase 2 Program Preliminary Results

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