Otis Gold Corp.(CVE:OOO)(OTCQX:OGLDF) unveiled Tuesday what it called "positive" additional column leach gold recoveries from coarse-crush bulk samples at its flagship Kilgore gold project in Idaho.
Together with previous column leach testing
conducted by prior operator Echo Bay Mines, as well as by Otis, these
latest results continue to show that the Kilgore Mine Ridge deposit is
"readily amenable" to standard heap-leach process technology, the miner
They also suggest that the gold ore is not particularly
sensitive to crush size as there was not a substantial decrease of gold
recovery in the coarser crush material. This means that the ore may not
require processing by a tertiary crusher, boosting the overall economics
of the deposit.
Otis said that tests further show that the
coarser crush material should be tested to see if part of the deposit
could be processed by run-of-mine material, resulting in even greater
cost savings for the gold miner.
Overall, the tests revealed that
the gold came out quickly in all samples from both size fractions, with
85 to 90 per cent of the recovered gold leaching in just 30 days.
results from column leach testing continue to be impressive, even for
relatively coarsely crushed material," said president and CEO, Craig Lindsay.
Kilgore Mine Ridge deposit continues to have excellent recovery rates
that will positively impact the economics of developing a potential
"In the future, we plan to acquire coarse enough material
for a run-of-mine test to help Otis make decisions as we move this
deposit towards potential commercial production."
cyanide and lime consumption were relatively low and the ore charges
did not require agglomeration pretreatment, Otis said.
column leach tests were done by McClelland Labs of Reno, Nevada on three
samples comprising oxidized and non-oxidized dike - both thought to be
responsible for the mineralizing fluids supplying gold to the host rock -
and oxidized lithic tuff, the dominant host rock at Kilgore.
dike samples and the lithic tuff sample were composited from drilled
PQ-diameter core that was stage crushed to a nominal 80 per cent,
passing a 38 mm (1.5 inch) screen.
Each sample was divided and
one split was further crushed to 80 per cent -12.5 mm (0.5 inch) to
directly compare the difference in gold recovery between the two crush
sizes, the company said.
Otis noted that only the oxidized dike
showed feed size sensitivity in regard to gold recovery in column leach
tests, possibly due to the shorter residence time of 78 days. Still, the
oxidized dike represents only an estimated 14 per cent of the deposit
In an interview with Proactive Investors in late April, CEO Lindsay
said that perhaps one of the greatest strengths of the project is the
metallurgy, something on which investors tend not to focus.
In the mid 1990s, Lindsay
notes that Kilgore was going to be Echo Bay's next production story,
but a drop in gold prices to well below $300 per ounce halted the
process. At the time, Echo Bay completed extensive column leach
metallurgy tests, achieving "very good" recovery rates.
followed up with additional column leach tests using 1/2” crush material
in late 2010, yielding similar results, with the announcement today
providing further positive evidence.
says that the larger the crush size, the less processing and crushing
of rock is required, which helps decrease capital costs, thereby
The entire Kilgore project,
which is 100 percent-owned by Otis with no underlying royalties, has two
to three million ounce gold potential, with the latest NI 43-101
resource delineating 487,000 ounces of indicated and inferred gold. The
company is now working on a new estimate that will incorporate all the
drilling through 2011.
The project is spread across 5,130 acres
in southeastern Idaho, 60 miles north of Idaho Falls, and is accessible
by road around 32 miles northeast of the town of Dubois and 15 miles
east of Interstate Highway 15.
says that an important achievement for the company this year was the
addition of 1,880 acres, boosting its land position at Kilgore by 58
percent and giving the miner flat land that is appropriate for heap
This year, Otis plans on drilling another 7,000
metres on its Mine Ridge deposit, completing the NI 43-101 resource
update and initiating a scoping study. Twelve-month environmental
baseline studies will start this summer, with the company having engaged
a contractor for the task.