VANCOUVER, Jan. 30, 2014 /PRNewswire/ - Sarama Resources
Ltd. ("Sarama" or the "Company") is pleased to
announce that preliminary metallurgical testing at its flagship
South Houndé Project in south-west Burkina Faso has returned encouraging results,
indicating potential for heap leach processing of oxide
mineralisation. Sarama is conducting the testwork to
establish a range of alternatives for the development of the South
Houndé Project, with the heap leach concept presenting an
attractive low-cost alternative.
Highlights
- Average gold extraction of 90.2% for oxide composite sample in
intermittent bottle roll testwork1
- Variability testwork on high-grade mineralisation samples
returned an average extraction of 93.0%. Variability testwork
on sediment-hosted mineralisation returned an average extraction of
75.4%. Both samples had low to moderate reagent
consumptions1
- Visual observations suggest that oxide material readily forms a
stable feed when agglomerated with cement
- Agglomeration testing indicates moderate cement requirements
with 6-10kg/tonne addition rate yielding acceptable pellet strength
and column slump levels2
- Percolation testing indicates that high solution flow rates
through the agglomerated product can be achieved
- Column leach testing has commenced on composite sample using
agglomeration with cement addition of 10kg/tonne
- Oxide component of the Inferred Mineral Resource at South
Houndé Project contains 298 koz of gold3
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1. |
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Samples control crushed to -25mm and -8mm screen sizes,
prior to leaching by sodium-cyanide solution in intermittent bottle
roll test over a 10 day period |
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<10% column height slump adopted as acceptable limit for
80mm diameter column with ~400mm charge height |
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6.82 Mt @ 1.4 g/t Au for 298 koz reported above 0.4 g/t
Au |
Preliminary Metallurgical Testwork for
Oxide Heap Leaching
A preliminary metallurgical testwork program has
been commenced by ALS Metallurgy Pty Ltd under the supervision of
Kappes, Cassiday & Associates Australia Pty Ltd ("KCAA")
to determine the amenability of oxide mineralisation to processing
by heap leaching. The testwork is regarded as preliminary and
as such, parameters and flowsheets are un-optimised. Notes
outlining the testwork approach and detailed results are presented
in Appendix A.
A composite oxide sample, weighing approximately
240kg, was generated from weathered quartz-feldspar-porphyry hosted
mineralisation in 6 individual diamond drill half-core samples
sourced from within the mineral resource. The constituent
holes were selected so as to provide reasonable representativity
across the MM Prospect which hosts the majority of the mineral
resources at the South Houndé Project.
In addition to this composite sample, two
variability samples were sourced to investigate, at a high level,
the leaching performance of high-grade gold mineralisation and
sediment-hosted gold mineralisation in intermittent bottle roll
("IBR") testing.
Intermittent Bottle Roll Leach
Testing
IBR testing, under which the samples are gently
rolled in a sodium cyanide solution for duration of 1 minute per
hour for a total test time of 10 days, is a first-pass test
designed to provide an insight into the potential leach performance
of a coarse crushed feed. KCAA's experience with other
testwork programs suggests that IBR testing can provide a good
indication of potential leaching performance in traditional heap
leach column tests.
The gold extractions and low reagent
consumptions achieved in the IBR testing indicate that the
mineralisation is potentially amenable to heap leaching (refer
Table 1). The generally high rates of extraction, while
influenced by the friable nature of the samples and the resulting
small particle size, are encouraging, and on this basis, the
Company has commissioned a column leach test on the -25mm composite
sample.
The IBR tests on the variability samples
indicate that high extractions can be achieved for both the
high-grade mineralisation and the mineralisation hosted in
sedimentary lithologies, the latter of which constitute a small
proportion of the South Houndé Project's mineral resource.
Table 1 -
Gold Extraction Results - Intermittent Bottle Roll
Test |
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Sample Description |
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Leach Residue
Particle Size |
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Calculated
Head Grade |
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Gold
Extraction
@ 240 Hours |
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Cyanide
Consumption |
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Lime Addition |
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% Pass 0.5mm |
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g/t Au |
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% |
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kg/tonne |
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kg/tonne |
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Oxide Composite -25mm |
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94% |
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1.94 |
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89.2 |
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0.56 |
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1.00 |
Oxide Composite -8mm |
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94% |
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1.90 |
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91.2 |
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0.51 |
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1.11 |
Average |
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1.92 |
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90.2 |
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0.54 |
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1.05 |
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High Grade Variability Sample -25mm |
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93% |
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7.53 |
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93.5 |
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0.62 |
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0.64 |
High Grade Variability Sample -8mm |
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93% |
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7.79 |
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92.5 |
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0.56 |
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0.77 |
Average |
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7.66 |
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93.0 |
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0.59 |
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0.70 |
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Sediment Variability Sample -25mm |
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60% |
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3.01 |
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77.7 |
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0.46 |
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0.31 |
Sediment Variability Sample -8mm |
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64% |
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2.69 |
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73.1 |
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0.66 |
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0.27 |
Average |
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2.85 |
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75.4 |
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0.56 |
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0.29 |
Agglomeration and Percolation
Testing
As is common with heap leaching of oxide
material, the fine and friable nature of the oxide composite sample
necessitated agglomeration with cement to provide a competent heap
leach feed. A series of tests was conducted on the -25mm
sample at cement dosage rates of 6kg/tonne feed, 12kg/tonne feed
and 18kg/tonne feed to assess ease of agglomeration, particle
stability and percolation characteristics in a column of
approximately 400mm height.
The tests indicated that, at all 3 cement dosage
rates, the composite sample was able to form an agglomerated
product that was visually acceptable. Agglomerate stability
also met minimum performance criteria with all 3 tests having less
than 10% height slump from initial placement after the introduction
of fluids and tapping to induce settlement. This result is
encouraging and indicates that low to moderate cement additions
would be required.
Percolation tests were conducted for each cement
dosage rate by measuring water flow through the column charged with
agglomerated product. The ability of a stacked heap leach
product to maintain stability and allow the leach solution to flow
freely and be well distributed throughout the heap is a key
determinant in the effective extraction of gold. The
composite sample performed very well with high flow rates being
achieved at all 3 cement doses.
Overall, these results are encouraging and
indicate that low to moderate cement additions would be
required. Based on the initial results from the agglomeration
and percolation testing, Sarama has moved to full column (200mm
diameter) leach testing of the -25mm oxide composite sample using
agglomeration with a cement dosage of 10kg/tonne feed.
Metallurgical Testwork Program for Fresh
Mineralisation
Following the completion of the preliminary
metallurgical testwork program on the fresh mineralisation at MM
and MC Prospects (refer news release September 16, 2013), Sarama has commenced a
follow-up testwork program to further investigate the amenability
of the fresh mineralisation to treatment with the BIOX® and Albion
Process™ methods.
The previous testwork demonstrated high gold
leach extractions of 89.9% for the fresh mineralisation when
subjected to flotation and oxidation prior to cyanidation.
The oxidation of the concentrate, achieved by roasting, was the key
determinant in the flowsheet to realize acceptable levels of gold
extraction. Sarama believes similar levels of oxidation could
potentially be achieved using the BIOX® and Albion Process™
methods, whilst potentially realizing cost and environmental
benefits compared to the roasting process.
A 495kg composite sample of fresh
mineralisation, with a head grade of 2.14g/t Au, has been sourced
from the MM, MC and Phantom Prospects within the mineral resource
at the South Houndé Project. The composite sample is
undergoing sulphide flotation to produce a pyrite-dominant
flotation concentrate which will then be subjected to oxidation
testwork at specialized facilities in Johannesburg (for the BIOX® process) and
Brisbane (for the Albion
Process™).
The oxidation testwork is designed as an
'orientation' or 'batch' scale and will test approximately 7-10kg
of concentrate for each method. Key metrics obtained by the
testwork programs will include degree of sulphide oxidation,
reagent consumptions, energy requirements and gold extraction.
BIOX® and the Albion Process™ are both
commercially viable treatment methods for sulphide-hosted gold
mineralisation, with the BIOX® method being used to produce
approximately 1.5Moz Au per annum in 11 operations worldwide.
Contingent upon successful test results, Sarama believes these
processes could be applied to an industrial gold processing
operation at the South Houndé Project.
As part of this program, flotation optimisation
testwork was conducted to investigate the potential to improve the
mass pull and/or gold recovery to concentrate characteristics
observed in the original 2013 testwork program (bulk flotation test
yielded 6.1% mass pull and 93.8% gold recovery to concentrate -
refer news release September 16,
2013). A series of scout flotation demonstrate that
the mineralisation floats very easily, achieving a +85% gold
recovery to concentrate in the first rougher flotation cell,
subject to the specific flowsheet used. The testwork also
shows that the concentrate is amenable to cleaning, reducing the
mass pull to final concentrate to 4.2% with a corresponding gold
recovery to concentrate of 88.9% at a sulphur content of
26.3%. Testwork details are listed in Appendix B.
Whilst the South Houndé Project is at a
preliminary stage, this optimisation work further demonstrates that
the mineralisation responds well to flotation and that the
concentrate as a feedstock for downstream oxidative processing can
be tailored to suit a range of specifications and/or operating
constraints.
Sarama's President and CEO, Andrew
Dinning commented:
"We see these early heap leach test results
as encouraging and look forward to the completion of the column
testing. Initial indications are that cement consumption will
be moderate and a stable agglomerated product will be readily
achieved, boding well for a simple and cost effective heap leach
alternative to treat oxide mineralisation at the South Houndé
Project.
Our testwork on the fresh mineralisation is
ongoing and we are confident that the BIOX® and the Albion Process™
methods will offer additional viable alternatives for the treatment
of this type of mineralisation.
Sarama's exploration efforts at the South
Houndé Project are continuing with a bias towards grade and
free-milling material and we are particularly keen to add to the
298koz1 of oxide material in the inferred mineral
resource."
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1. |
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6.82 Mt @ 1.4 g/t Au for 298koz Au (at a 0.4 g/t Au
cut-off)
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For further information on the Company's
activities, please contact:
Andrew Dinning or Paul Schmiede
e: info@saramaresources.com
t: +61 (0) 8 9363 7600
Neither TSX Venture Exchange nor its Regulation
Services Provider (as that term is defined in policies of the TSX
Venture Exchange) accepts responsibility for the adequacy or
accuracy of this release.
About Sarama Resources Ltd
Sarama Resources Ltd (TSX-V: SWA) is a West
African focused gold explorer with substantial landholdings in
Burkina Faso, Liberia and Mali.
Sarama's flagship properties are situated within
the Company's South Houndé Project area in south-west Burkina Faso. Located within the prolific
Houndé greenstone belt, Sarama's exploration programs have built on
significant early success to deliver a maiden Inferred Mineral
Resource estimate of 1.5 Moz gold2. Outside of
Burkina Faso, Sarama is focused on
consolidating a number of under-explored landholdings in other
emerging and established mining jurisdictions.
Incorporated in 2010, the Company's Board and
management team have a proven track record in Africa and a strong history in the discovery
and development of large-scale gold deposits. Sarama is well
positioned to build on its current success with a strong financial
position and a sound exploration strategy across its property
portfolio.
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29.13 Mt @ 1.6 g/t Au (at a 0.8 g/t Au cut-off)
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Caution Regarding Forward Looking
Statements
Information in this news release that is not
a statement of historical fact constitutes forward-looking
information. Such forward-looking information includes
statements regarding the Company's future exploration program and
the Mineral Resource estimate. Actual results, performance or
achievements of the Company may vary from the results suggested by
such forward-looking statements due to known and unknown risks,
uncertainties and other factors. Such factors include, among
others, that the business of exploration for gold and other
precious minerals involves a high degree of risk and is highly
speculative in nature; Mineral Resources are not Mineral Reserves,
they do not have demonstrated economic viability, and there is no
certainty that they can be upgraded to Mineral Reserves through
continued exploration; few properties that are explored are
ultimately developed into producing mines; geological factors; the
actual results of current and future exploration; changes in
project parameters as plans continue to be evaluated, as well as
those factors disclosed in the Company's publicly filed
documents.
There can be no assurance that any
mineralisation that is discovered will be proven to be economic, or
that future required regulatory licensing or approvals will be
obtained. However, the Company believes that the assumptions and
expectations reflected in the forward-looking information are
reasonable. Assumptions have been made regarding, among other
things, the Company's ability to carry on its exploration
activities, the sufficiency of funding, the timely receipt of
required approvals, the price of gold and other precious metals,
that the Company will not be affected by adverse political events,
the ability of the Company to operate in a safe, efficient and
effective manner and the ability of the Company to obtain further
financing as and when required and on reasonable terms. Readers
should not place undue reliance on forward-looking
information.
Sarama does not undertake to update any
forward-looking information, except as required by applicable
laws.
Qualified Person's Statement
Scientific or technical information in this
news release that relates to metallurgical testwork and mineral
processing for oxide mineralisation is based on information
compiled or approved by Randall
Pyper. Randall Pyper is
an employee of Kappes, Cassiday & Associates Australia Pty Ltd
and is considered to be independent of Sarama Resources Ltd.
Randall Pyper has verified the data
underlying the information in this news release pertaining to the
metallurgical testwork completed on the Company's behalf. The
verification was conducted by Randall
Pyper through a review of relevant lab results provided
directly by the engaged laboratory. Randall
Pyper is a Fellow in good standing of the Australasian
Institute of Mining and Metallurgy and has sufficient experience
which is relevant to the commodity, style of mineralisation under
consideration and activity which he is undertaking to qualify as a
Qualified Person under National Instrument 43-101.
Randall Pyper consents to the
inclusion in this report of the information, in the form and
context in which it appears.
Scientific or technical information in this
news release that relates to metallurgical testwork and mineral
processing for fresh mineralisation is based on information
compiled or approved by John
Fodor. John Fodor is an
employee of Orway Mineral Consultants Pty Ltd and is considered to
be independent of Sarama Resources Ltd. John Fodor has verified the data underlying the
information in this news release pertaining to the metallurgical
testwork completed on the Company's behalf. The verification
was conducted by John Fodor through
a review of relevant lab results provided directly by the engaged
laboratory. John Fodor is a Fellow
in good standing of the Australasian Institute of Mining and
Metallurgy and has sufficient experience which is relevant to the
commodity, style of mineralisation under consideration and activity
which he is undertaking to qualify as a Qualified Person under
National Instrument 43-101. John
Fodor consents to the inclusion in this report of the
information, in the form and context in which it appears.
Scientific or technical information in this
news release that relates to the preparation of the Company's
mineral resource estimate is based on information compiled or
approved by Adrian Shepherd.
Adrian Shepherd is an employee of
Cube Consulting Pty Ltd and is considered to be independent of
Sarama Resources Ltd. Adrian
Shepherd is a chartered professional member in good standing
of the Australasian Institute of Mining and Metallurgy and has
sufficient experience which is relevant to the commodity, style of
mineralisation under consideration and activity which he is
undertaking to qualify as a Qualified Person under National
Instrument 43-101. Adrian
Shepherd consents to the inclusion in this report of the
information, in the form and context in which it appears.
Appendix A - Preliminary Heap Leach Metallurgical Testwork
Appendix B - Fresh Mineralisation Scout Flotation Testwork
SOURCE Sarama Resources Limited