Preliminary results from Tiris project
Mindoro Resources Ltd MIO
Shares issued 16,305,539 Nov 18 close $0.18
Thu 19 Nov 98 News Release
Mr. Tony Climie reports
PHASE 2 PROGRAM
The company has received preliminary results from the phase 2 exploration
program on the Tiris project. Work has focused on detailed follow-up of the
Harimau prospect, a gold target identified by previously-announced strong
and extensive stream sediment gold and silver anomalies (news releases in
Stockwatch March 3, May 7, and July 28, 1998).
The accompanying figure shows the location of the Harimau prospect (West
block, Tiris CoW).
Eighty-seven kilometres of grid lines were cut over the Harimau prospect
and soil samples collected every 25 metres on 200 metre-spaced lines. Every
second sample (50m apart) was analyzed. Soils were sampled from
approximately 50 centimetre-deep holes (B-horizon) and shipped to Intertek
Testing Services/Bondar Clegg in Jakarta, Indonesia, for analysis of gold,
silver, copper, and zinc. Gold analyses were performed on the fine fraction
(-80 mesh) by standard fire assay using a 50 gram charge, with a lower
detection limit of 5 parts per billion. The laboratory, as part of its
normal quality-assurance procedures, routinely assays a total of five
standard, repeat and blank samples per 45 samples analyzed. These assay
results varied within normal limits.
Other work included an airborne magnetometer survey (1,160 line km) on 200
metre-spaced lines over the entire Tiris CoW, plus detailed 100m infill
lines over the Harimau prospect. The contractor was Jakarta-based PT World
Geoscience Indonesia. Only preliminary data from the 200 metre-spaced lines
have been received to date. A structural interpretation using satellite
synthetic aperture radar has been completed by Earth Resource Surveys
(Vancouver), and ground mapping and prospecting are still under way on the
project, as are detailed infill investigations.
PHASE 2 PROGRAM PRELIMINARY RESULTS
Phase 2 exploration has identified three broad gold soil anomalies within
the Harimau prospect: Harimau Selatan, Harimau Barat and Harimau Utara, as
well as several others not yet ground-checked.
Soil geochemistry results are based on 1,371 samples that have been
analyzed to date. The gold values ranged from less than 5 to 862 ppb and
averaged 37 ppb. Duplicate samples were collected at every 20th site and
submitted to ITS under different sample numbers. Results for the 113
duplicates showed considerable variability because of the presence of
coarse gold. As described below the amount of gold in the soil samples has
apparently been underestimated in the fine-fraction analyses.
HARIMAU SELATAN ANOMALY
The Harimau Selatan anomaly is on the southern edge of the 1,000 ppb gold
stream sediment anomaly. This gold soil anomaly likely represents a
different source from the main stream sediment response (greater than 4,000
ppb), which is 1.5km further north and in several different drainage
systems. As defined by the 50 ppb gold contour, the soil anomaly is 1.7km
by 1km, from which 146 samples range from 5 to 779 ppb gold (average 145
ppb). The greater than 100 ppb area (91 samples) is only slightly smaller,
covering 1.5km by 0.85km. Geological information, limited to stream beds,
indicates the area consists of strongly altered dacitic pyroclastic
volcanics. Preliminary interpretations from the SAR and airborne magnetic
surveys indicate the anomaly lies on the southern flank of intermediate
intrusive rocks.
The overall anomaly shows a close correlation with topographically high
ground on a moderately dissected plateau. At least four areas of localized
surface mining from the Dutch colonial era, dating from around 1910, were
noted in the area. Mining consisted of hydraulic sluicing of near-surface
oxide material, and was limited to areas around stream channels
representing 3 per cent to 5 per cent of the Harimau Selatan soil anomaly
area. The strongest soil anomalies at Harimau Selatan occur several hundred
metres from the Dutch mining sites. There is little to no contamination
related to these old mining operations that may have affected the soil
survey results.
Both the historical Dutch sluicing operations and variability of the
fine-fraction soil data indicated the presence of coarse gold within the
oxide zone. This was tested by panning the soil from a test site, and by
analyzing a line of unsieved soil samples and comparing results with sieved
(fine-fraction) samples. A total of 12 grains of visible gold (up to
approximately 0.2 mm diameter) was panned from a 1 kilogram soil sample.
The high clay content resulting from the intense hydrothermal alteration
and weathering likely reduces the amount of gold recoverable by simple
panning. Sixty-four soil samples from the test soil line contained from
less than 5 to 1,963 ppb gold (1.96 grams per tonne) and averaged 127 ppb
for the entire test. For comparison, the fine-fraction (-80 mesh) ranged
from 7 to 335 ppb, and averaged 73 ppb gold.
The presence of coarse gold within the oxide zone has therefore been
confirmed. Stream bank and old sluicing exposures indicate the oxide zone
is at least 30 m thick. If the fine-fraction soil anomaly is indicative of
an oxide gold resource, it covers a potentially large area (1.7km by 1km)
which would probably be amenable to shallow, bulk mining methods. Follow-up
to investigate this shallow oxide resource potential is in progress. This
includes shallow (1 to 3m, initially) hand auger drill holes on a
wide-spaced grid (400m by 400m), infill gridding, soil sampling, and
sampling of Dutch workings. Primary mineralization potential at depth will
be evaluated at a later date via ground geophysics, leading to drilling if
justified.
HARIMAU BARAT ANOMALY
Located 400m northwest of Harimau Selatan, this soil anomaly is in the
interpreted source area of the strongest stream sediment anomalies (up to
18,450 ppb gold and 17 parts per million silver). From the initial 50 by
200 metre-spaced fine-fraction soil samples, the gold anomaly is currently
defined by 15 samples, ranging from 2 to 862 ppb (average 171 ppb), with
four samples greater than 200 ppb. The anomaly is currently 500m long, with
samples having greater than 50 ppb gold occurring across 400m (3 adjacent
lines). Limited panning (one site) recovered visible gold from the soil.
There are no old mining sites in the anomaly area.
Geological information is limited to stream beds where intensely altered
(silica-adularia-clay) dacitic pyroclastics are intermittently exposed.
Abundant intermediate intrusive float boulders occur in several streams.
Airborne magnetics suggests the presence of extensive intermediate dykes
and stocks intruding the pyroclastics.
The Harimau Barat prospect is considered high-priority due to the strong
stream sediment anomalies draining from the area and the extent and
intensity of alteration. It is believed that mineralization is related to
the intrusive contact with the pyroclastics. Detailed infill gridding, soil
geochemical sampling, and geological surveys are in progress.
HARIMAU UTARA ANOMALY
Located 250m northeast of the Harimau Selatan anomaly, the Harimau Utara
soil anomaly extends approximately 1.2km by 0.75km. Defined by the greater
than 50 ppb gold contour, it comprises 65 samples, ranging from 10 to 296
ppb (average 104 ppb, with 31 samples greater than 100 ppb). Harimau Utara
also flanks the interpreted intrusive bodies. Strong and extensive
alteration exists in both pyroclastic outcrop and float. There are no old
surface workings in the area of this anomaly. Only limited follow-up has
been undertaken to date.
PLANNED WORK
Continuing phase 2 work will focus on an initial follow-up of the Harimau
Selatan and Harimau Barat soil anomalies. This will consist of detailed
infill soil sampling, shallow hand-auger soil sampling, and rock sampling.
The phase 2 program will be completed by the end of November, with final
results available in December.
(c) Copyright 1998 Canjex Publishing Ltd. canada-stockwatch.com |
