Otis Reports Favourable Metallurgical Results from Kilgore
15 April 2019 - 10:30PM
Otis Gold Corp. (“
Otis” or the
“
Company”) (
TSX-V:
OOO) (
OTC: OGLDF) is pleased to
announce that metallurgical work conducted at Kilgore on the lower
volcanic stratigraphy, referred to as the “Sill Domain”, has
returned favourable simulated heap leach gold recovery results of
83.5% on 38mm (1.5”) crush material. Additionally, final gold
grades from column leach tests on crushed core show a 59% increase
in gold grade. The results continue to demonstrate very favourable
metallurgy at Kilgore, and the increase in recovered gold grade
confirm that gold grades in the existing resource are potentially
under-reported.
Highlights of the metallurgical testing results
are as follows:
- Bottle roll leach tests on Sill
Domain material achieved gold extractions averaging 86.4% at 10
mesh, and 93.0% at 200 mesh;
- Column leach test results from Sill
Domain material show 74.8% gold recovery from 12.5mm (0.5”) crushed
core, and 83.5% gold recovery from 38mm (1.5”) crushed core. The
38mm crushed core leached slower but has higher overall gold
extraction; and
- Final gold test grades from Sill
Domain material show a 59% increase, with calculated final grades
returning up to 1.42 g/t Au from initial head assay test grades of
0.89 g/t Au.
Metallurgical Testing -
2019Otis submitted approximately 1,400 kg of whole PQ core
from drill hole 17OKC-379 for metallurgical testing; the hole is a
twin of 17OKC-356 that returned 129.6 metres(m) averaging 1.66 g/t
Au from 155.4 to 285.0m, including 24.4m averaging 3.45 g/t Au from
157.0 to 181.4m (true widths are estimated between 80% and 100% of
the drilled interval). These drill results come from a package of
lithologies including Tertiary volcanic and Cretaceous sedimentary
rocks. Further details of the metallurgical test work can be found
on the Otis website under the Kilgore metallurgy tab at
www.otisgold.com.
Results from the metallurgical testing are
summarized as follows:
- Bottle roll leach tests on Sill
Domain material achieved gold extractions averaging 86.4% at 10
mesh, and 93.0% at 200 mesh; silver extraction during bottle roll
leach tests average 57%;
- Column leach test results from Sill
Domain material gave 74.8% gold recovery from 12.5mm (0.5”) crushed
core, and 83.5% recovery from 38mm (1.5”) crushed core;
- Final gold test grades from Sill
Domain material show a 59% increase, with calculated final grades
of up to 1.42 g/t Au returned from initial head assay test grades
of 0.89 g/t Au;
- Optical mineralogy combined with
whole rock and rare earth element analysis confirms that the Sill
Domain material are porphyritic andesite flows; and
- Aspen formation rocks have been
confirmed as quartz-adularia altered, arkosic, turbidite
sediments.
Metallurgical testing at Kilgore is ongoing,
with current work comprising a suite of tests on PQ core from near
surface volcanic rocks. Testing will include the addition of 76mm
(3”) column leach tests to better simulate run-of-mine open pit
heap leaching (ROM-OPHL).
Historic MetallurgyThroughout
the history of the Kilgore project, metallurgical studies have been
ongoing. The following represents a summary of this metallurgical
testing. It is important to note that tests conducted before the
introduction of NI 43-101 do not meet current reporting
requirements and are provided for reference only. For full details
on metallurgical testing, please refer to NI 43-101 Technical
reports dated August 14, 2018 and July 31, 2012; which can be found
on SEDAR or the Otis website.
Echo Bay – 1995/1996 Metallurgical
TestingEcho Bay Mines submitted drill core and reverse
circulation cuttings for metallurgical testing in 1995 and 1996, in
anticipation of starting up a small-scale open pit heap leach
mining operation on the Kilgore deposit. The material submitted was
divided into three classes: oxide, sulfide and mixed material.
Highlights of 1995 and 1996 metallurgical testing were:
- Bottle roll test gold extractions
varied from 82.9% to 94.8% for the three material types;
- Column leach tests on oxide
material of 12.5mm (0.5”) crushed core returned gold extraction up
to 94.3%;
- Column leach tests on mixed
material of 25mm (1”) crushed core returned gold extraction up to
85.5% after 75 days; and
- An independent study in 1996
concluded that there is no sulfide mineralization and that
variation in gold extractions over time is due to porosity,
therefore longer leach times would favor increased gold
extractions.
Further details of the Echo Bay’s metallurgical
test work can be found on the Otis website under the Kilgore
metallurgy tab at www.otisgold.com.
Otis Gold – 2010/2011 Metallurgical
TestingIn 2010, Otis Gold submitted four composite samples
to McClelland Laboratories Inc. of Reno, Nevada. The composites
comprised three principal host rock types identified at that time
from the Kilgore deposit: Aspen sandstone, lithic tuff, and felsic
dike and were derived from four drill holes: 09OKC-195, -197, -205
and -206. The calculated head grades are illustrated in the table
below.
Rock type |
Gold grade g/t |
Silver Grade g/t |
Lithic tuff_1 |
0.55 |
3.77 |
Lithic tuff_2 |
0.69 |
5.82 |
Felsic Dike |
1.47 |
7.54 |
Aspen Sandstone |
1.44 |
3.77 |
McClelland stated in conclusion that:
- The Kilgore drill core composites
were amenable to simulated heap leach cyanidation treatment, at an
80% passing 12.5mm (0.5”) feed size;
- Gold recovery rates generally were
fairly slow. Column test gold extractions ranged from 70% to 85%,
after 80 to 109 days of leaching; and
- Gold recoveries from bottle roll
tests obtained after 96 hours ranged from 50.0% to 78.9%.
Otis Gold - 2012 Metallurgical
TestingThree drill core composites were submitted to
McClelland Laboratories Inc. for metallurgical testing with the
objective of determining heap leach amenability of the composites
to comparative feed sizes. The three composites came from whole PQ
core from drill holes 11OKC-285 and -287, twin holes of 11OKC-258
and 10OKC-228 respectively. The composites comprised 38m (124.5 ft)
of oxidized lithic tuff with an average grade of 0.46 g/t Au; 38.1
m (125.0 ft) of oxidized felsic dike, and 32.9m (108 ft) of
unoxidized felsic dike with an average grade of 1.15 g/t Au (true
widths are estimated between 80% - 100% of the drilled
interval).
McClelland stated in conclusion that:
- All three core composites were
amenable to simulated heap leach cyanidation treatment at 80%
passing both -38mm (1.5”) and 12.5mm (0.5”) feed sizes;
- 38mm (1.5”) feed size gave gold
extractions from 71% to 85%; 12.5mm (0.5”) feed size gave gold
extractions ranging from 74.5% to 85.5%;
- Oxidized lithic tuff did not show
feed size sensitivity to gold extraction;
- Oxidized felsic dike gold
extraction increased with decreasing feed size; and
- Unoxidized felsic dike required a
longer leach cycle than the other two composites.
Alan Roberts, MSc, CPG, Vice President of
Exploration, serves as the Qualified Person for this news release
and has reviewed and approved the technical content contained
herein.
About the Kilgore ProjectThe
Kilgore project lies on the north-eastern margin of the
Miocene-Pliocene Kilgore Caldera complex in the Eastern Snake River
Plain, Idaho. The Kilgore project includes the Kilgore deposit with
a current NI 43-101 resource comprising: Indicated Resource of
825,000 ounces Au in 44.6 million tonnes at a grade of 0.58 g/t Au
and an Inferred Resource of 136,000 ounces Au in 9.4 million tonnes
at a grade of 0.45 g/t Au (see 2018 Kilgore Project NI 43-101
Technical Report and Mineral Resource Estimate dated August 14,
2018). The Kilgore deposit is a low-sulphidation, gold bearing,
quartz-adularia epithermal system hosted in Tertiary volcanic
rocks, local Tertiary intrusive rocks, and basement Late
Cretaceous, Aspen Formation sedimentary rocks.
About the Company Otis is
a resource company focused on the acquisition, exploration, and
development of precious metal deposits in Idaho, USA. Otis is
currently developing its flagship property, the Kilgore project,
located in Clark County, Idaho and the Oakley project, located in
Cassia County, Idaho.
ON BEHALF OF THE BOARD
“Craig T. Lindsay”
President & CEO
For additional information, please contact:
Mr. Tony Perri – Corporate Development
Tel: (604) 424-8100 Email: tony@otisgold.com
Neither TSX Venture Exchange nor its Regulation
Services Provider (as defined in the policies of the TSX Venture
Exchange) accepts responsibility for the adequacy or accuracy
of this release.
Forward Looking
Statements |
Certain information in this
news release contains forward-looking statements and
forward-looking information within the meaning of applicable
securities laws. All statements, other than statements of
historical fact are forward-looking statements. Forward-looking
statements are based on the beliefs and expectations of Otis as
well as assumptions made by and information currently available to
Otis's management. Such statements reflect the current risks,
uncertainties and assumptions related to certain factors including,
without limitations, drilling results, the Company's expectations
regarding mineral resource calculations, capital and other costs
varying significantly from estimates, production rates varying from
estimates, changes in world metal markets, changes in equity
markets, uncertainties relating to the availability and costs of
financing needed in the future, equipment failure, unexpected
geological conditions, imprecision in resource estimates or metal
recoveries, success of future development initiatives, competition,
operating performance, environmental and safety risks, delays in
obtaining or failure to obtain necessary permits and approvals from
local authorities, community agreements and relations, and other
development and operating risks. Should any one or more of these
risks or uncertainties materialize, or should any underlying
assumptions prove incorrect, actual results may vary materially
from those described herein. Although Otis believes that
assumptions inherent in the forward-looking statements are
reasonable, forward-looking statements are not guarantees of future
performance and accordingly undue reliance should not be put on
such statements due to the inherent uncertainty therein. Except as
may be required by applicable securities laws, Otis disclaims any
intent or obligation to update any forward-looking statement. |
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