Phase 1 work completed on Tiris project
Mindoro Resources Ltd MIO
Shares issued 13,515,000 Jul 23 close $0.32
Mon 27 Jul 98 News Release
Mr. Tony Climie reports
The phase 1 program on the Tiris project, consisting of stream sediment
geochemistry, reconnaissance geological mapping and prospecting has been
completed. New results have extended and defined the previously reported
Harimau prospect in the west part of the project. Three new gold anomalies
were also located in the east part of the project: Kelawar, Tiku Hilir and
Semambu.
The work was supervised by A. Buskas and performed by exploration crews of
PT Handal Srirajasa of Jakarta, Indonesia, Mindoro's local geological
consultant. A total of 1,648 stream sediment samples have been collected,
for a sample density of 16.5 samples per square kilometre. Initially
weighing approximately 500 grams each, samples were sieved on site and the
fine (-80 mesh) fractions shipped to Intertek Testing Services in Jakarta,
Indonesia, for analysis of gold, silver, copper, lead and zinc. The gold
analyses were performed by standard fire assay using a 50 gram charge, with
a lower detection limit of 2 parts per billion. A total of 53 standard
samples were inserted into the analytical batches. Gold analyses varied
within normal limits for these standards. Duplicate samples were collected
at every twentieth site and submitted to Intertek under different sample
numbers. Results for the 80 duplicates also varied within normal limits.
The gold values for the entire data set of 1,648 samples ranged from 0.5 to
18,450 ppb and averaged 226 ppb.
A total of 501 rock samples were collected from throughout the project and
analyzed by Intertek using the standard fire assay technique on 50 gram
charges, with atomic absorption finish. Lower detection limit is 0.005
parts per million or grams per tonne. The rocks were collected to establish
gold background and grades within various alteration and lithologic types.
Because of an absence of outcrop between streams due to hydrothermal
alteration and tropical weathering, the rock samples cannot be considered
as representative of the area as a whole. Rock values ranged from less than
0.005 to 11.7 ppm (11.7 g/t) and averaged 0.14 ppm gold.
The Harimau prospect was the subject of March 3 and May 7, 1998 news
releases in Stockwatch. The prospect is now defined by a total of 249
stream sediments greater than 100 ppb gold, ranging from 102 to 18,450 ppb
(18.4 g/t), and averaging 1,338 ppb. The greater than 100 ppb gold contour
defines an area of about 6.5 by 6km, covering 10 major unrelated drainages.
The greater than 1,000 ppb (1 g/t) gold contour defines an area of about
4.5 by 3.5km, and covers five unrelated drainage systems. The 1,000 ppb
contour has also been closed off by the additional sampling and appears to
fall entirely within the Tiris CoW.
There is a strong correlating silver anomaly and supporting copper, lead,
and zinc anomalies. The March 3 release describes extensive (multi-km
scale) strong to intense hydrothermal alteration identified as a low
sulphidation (quartz adularia) system affecting a sequence of dacitic
pyroclastics, epiclastics (reworked pyroclastics) and hydrothermal breccias
intruded by basaltic andesite stocks or dykes.
A total of 216 rock samples have been assayed from the Harimau prospect.
Results range from less than 0.005 ppm to 9.02 ppm (g/t) gold (average
0.214 ppm). The maximum gold sample also contains 520 ppm silver. Thirteen
of these rock samples, from six unrelated drainages, returned values in
excess of 1 ppm (g/t) gold (average 2.4 ppm). This is from an area of about
2.5 by 2.5km that is also coincident with the 1,000 ppb stream sediment
area. These also include mineralization located in outcrops 1.3km apart,
with two samples (a grab and a composite grab) assaying 1.78 and 1.73 g/t
gold respectively.
These rock results are considered particularly encouraging as they suggest
that the areally extensive stream sediment anomaly, which is associated
with equally extensive hydrothermal alteration, reflects mineralization in
bedrock. Grades which are considered to be of economic interest have been
obtained from float in unrelated drainage systems over an extensive area.
However, it is emphasised that due to absence of outcrop, there is still no
information from the great majority of the prospect, i.e., the large areas
(interfluves) between the stream channels which are up to 1km apart. It is
considered that soil geochemistry will be an effective method of locating
blind mineralization within these interfluves. A great deal of systematic
work will be required to locate, define and evaluate the sources of
mineralized rocks, and other potential areas of mineralization within the
large target area.
The greater than 100 ppb gold stream sediment contour defines an area of
about 1.3 by 0.5km covering three separate drainages. Values range from 158
to 5,360 ppb gold (12 samples) and average 1,340 ppb. Geology consists of
dacitic pyroclastics, epiclastics and andesitic intrusions. Hydrothermal
alteration is strong and consists of chloritization, pyritization,
silicification, adularization and argillization. Seven rock samples
collected during prospecting in the region ranged from less than 2 ppb to
0.179 ppm gold (average 0.039 ppm ). However, exposure is poor in this area
and it is likely that the source of the anomaly remains unsampled.
The greater than 25 ppb gold stream sediment contour defines an area of
about 2.4 by 0.8km covering 13 tributaries of the Tiku River. Values range
from 26 to 2,940 ppb gold and average 490 ppb. Geology consists of dacitic
pyroclastics, epiclastics and andesite. Hydrothermal alteration noted
includes chloritization, silicification, pyritization and argillization.
Rock sampling was not possible due to high wet season water levels. The
anomaly falls on a northwesterly trend along which also occurs the Rawas
gold mine of Barisan Tropical Mining, 4km to the south-east, Mindoro's
Kelawar anomaly, 1.5km to the north-west, and BTM's Telun Merangin
prospect, 4km to the north-west.
The Semambu prospect is reflected by two subtle stream sediment anomalies
of greater than 10 ppb gold. The northernmost anomaly covers an area of
about 1.3 by 0.9km in four drainage systems with 22 samples ranging from 10
to 69 ppb gold (average 10 ppb). The second anomaly is immediately to the
south and is 1.6 by 0.8km in size. Eight sediment samples ranged from 11 to
461 ppb gold (average 145 ppb). Moderately strong copper and zinc anomalies
extend from Semambu to the southeast corner of the project. Geology at
Semambu consists of dacitic pyroclastics and epiclastics intruded by
andesitic stocks. Strong hydrothermal alteration occurs over an area at
least 0.9 by 0.5km, and consists of chloritization, pyritization,
silicification and argillization. Abundant quartz float occurs in streams,
with 56 rock samples collected from the area ranging from below detection
limit to 1.94 ppm (g/t) gold and averaging 0.106 ppm.
The significance of these three new targets will only be established with
additional work, but these initial results indicate that follow-up is
warranted.
A phase 2, detailed exploration program will commence by the end of July.
This will consist of an airborne magnetic survey, detailed soil
geochemistry and geological surveys, prospecting, trenching and systematic
rock sampling. Initial work will focus on the high priority Harimau
prospect. Objective is to define drill targets by year end. Mindoro's
management is extremely encouraged by the results to date and the potential
it sees at Tiris.
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