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Indonesia
Deep drilling success at Wonogiri project
RESULTS from drilling at the Randu Kuning
prospect of Augur Resources’ Wonogiri Gold-
Copper project in Central Java have confirmed
the extension of mineralization at depth and to
the north. Two additional drill rigs are now on
site for further drilling targeting extensions for
potential high grade mineralization.
Drilling at Augur Resources’ Wonogiri project in Central Java.
One hole was drilled to test for mineralization
below a previous hole that returned 199
metres @ 0.46 grams/tonne gold and 0.13%
copper. The new hole was drilled to a depth
of 456 metres and intersected a number of
mineralized zones including 95.5 metres from
41 metres @ 0.74 grams/tonne gold and
0.16% copper which included a high-grade
zone of 5 metres from 82 metres @ 5.08
grams/tonne gold and 0.50% copper.
This zone indicates that high-grade zones
may be viable targets within the Randu Kuning
porphyry system. Other intersections in this
hole include 66 metres from 198.5 metres @
0.47 grams/tonne gold and 0.11% copper, including
3 metres from, 215.5 metres @ 2.62
grams/tonne gold, 0.48% copper and 3.5
grams/tonne silver, and a further 7.0 metres
from 269.5 metres @ 0.32 grams/tonne gold
and 0.16% copper.
Another hole was drilled to test for down
dip extension of mineralization identified in a
previous hole that returned 123.5 metres @
1.42 grams/tonne gold and 0.22% copper
and a further 65 metres @ 1.03 grams/tonne
gold and 0.17% copper. The new hole intersected
near-surface mineralization including
96 metres @ 0.54 grams/tonne gold and
0.13% copper in altered dioritic porphyry before
intersecting a post-mineralized banded
quartz and magnetite intrusion.
Other intersections in this hole include 6.0
metres from 166 metres @ 0.57 grams/tonne
gold, 29 metres from 246 metres @ 0.63
grams/tonne gold and 0.10% copper, and a
further 18 metres from 282 metres @ 0.30
grams/tonne gold.
Interpretation of core has concluded that
Randu Kuning consists of multiple porphyry
intrusives indicating a prolonged intrusive history.
Extensive alteration may be indicating a
deeper mineralizing source which has yet to
be drill tested. A drill rig capable of testing targets
to more than 1000 metres has arrived
on site to test for deeper high grade zones
on the flanks of the porphyry intrusions.
Augur has received preliminary flotation
metallurgical results for three sulphide samples
and two oxide samples. Initial first pass
tests were focused on recovery from the sulphide
portion which is expected to be the
bulk of the deposit. The results indicate very
good recoveries with a recovery range of
78.6% to 88.7% with a mean of 82.7% for
the gold and a recovery range of 92.1% to
96.1% with a mean of 94.1% for the copper.
Results for the oxide component range from
58.1% to 69.6% for gold and 16.2% to 26%
for copper. The lower copper recoveries in
the oxide were expected given the tests were
focused on recovery of copper sulphides.
Further testing will be undertaken with a
focus on determining an appropriate
process for recoveries in the oxide zone and
gravitational testing for further improving the
gold recovery.
Full production achieved at Toka Tindung
FULL production has started at Archipelago
Resources’ 95%-owned Toka Tindung gold
mine in North Sulawesi province. The operation
achieved its targeted production rate in
early November and was expected to produce
at least 60,000 ounces of gold by the
end of 2011. Annual output during 2012 and
for the remaining life of the mine is expected
to be 150,000 ounces.
Archipelago is mining from the Toka Tindung
open pit as well as the satellite deposits of Pajajaran
and Araren, and is continuing its exploration
of the area covered by the mining permit.
The company’s chief executive officer Marcus
Engelbrecht says, “Meeting our production
objective is a significant achievement for
Archipelago and our ability to generate positive
cash flow will provide the platform for
meaningful growth.
“Having successfully established our production
base, the company is committed to
pursuing further drilling programs at Toka Tindung.
This will support organic production
growth at Toka through increased reserves,
additional sources of ore and greater production
optionality.”
The 2011 production fell well short of the initial
forecast of 110,000 ounces due to a number
of complications during the mine’s ramp-up.
While such problems are common during mine
start-ups, the company was encouraged that
its annual throughput rate was achieved during
the final quarter and is confident that the 2012
production guidance will be met.
Archipelago is also on track to report an increase
in its reserves and resources following
an increase in exploration and drilling since
completion of the feasibility stage.
Meanwhile, the company has also announced
that it will not proceed with the Pac-
Lang joint venture in Vietnam. The decision
follows a comprehensive review of the work
conducted there to date. The company says
that the exploration results do not justifying
further expenditure.
40 | ASIA Miner | January/February 2012