Cora Gold Limited /
EPIC: CORA.L / Market: AIM / Sector: Mining
7 October 2024
Cora Gold Limited
('Cora' or 'the
Company')
Multi-element analysis highlights
multiple gold deposit associations at Madina Foulbé in East
Senegal
Cora Gold Limited, the West African focused
gold company, is pleased to announce the results of ICP-MS (4
acids) analysis from its recently completed reconnaissance Reverse
Circulation ('RC') drilling programme at the Tambor gold anomaly
(3km long by 1.6km wide gold soil anomaly @ >20ppb), which is
one of four key target areas within the Company's Madina Foulbé
exploration permit in the Kenieba Project Area ('the Project') of
east Senegal.
Due to the shallow nature of the reconnaissance
drill programme into the underlying bedrock, the ICP-MS data in
conjunction with the corresponding gold assays, which included a
best drill result of 10m @ 4.41 g/t gold ('Au') from 41m depth, has
provided the Company with a larger dataset from which to understand
and interpret the large Tambor gold soil anomaly. These results
together with the Project's proximal location to several Tier 1
gold deposits located within the Kédougou-Kéniéba Inlier ('KKI')
(see figure 1) underpin the importance and possible large scale of
in-situ bed rock gold mineralisation at the Tambor
anomaly.
MULTI-ELEMENT
STUDY HIGHLIGHTS
●
2,018 samples analysed by ALS laboratories
(Johannesburg), using ICP-MS (4 acids) for multi-element data (46
elements per sample)
●
Data was interpreted in IMDEX's ioGAS software by
industry renowned consultant Dr. Nick Oliver (HCOV
Global)
●
Results indicate that gold mineralisation is
associated with an Intrusion Related Gold System ('IRGS'); these
systems can be massive in size, for example Morila (Mali); Donlin
Creek-Fort Knox-Pogo (Yukon / Alaska); and Kidston
(Australia)
●
Each of the 10 drill targets has a distinct
geochemical signature through their multi-element associations,
alteration type and lithologies present, enabling the Company to
rank and prioritise the targets for future exploration
expenditure
●
In identifying the possible deposit models for
gold mineralisation, future exploration can take into the account
their typical deposits properties; IRGS deposits tend to have
subtle magnetic signatures, lower chargeable anomalies and a more
distinct spatial relationship with intrusions
●
With more than 50% of holes drilled ending in
mineralisation (>0.1 g/t Au and <5m from end of hole), using
the trends of the elements associated with gold, and depending on
the host lithologies, results show that mineralisation is likely to
continue past the end of the hole in most instances with deeper
drilling now required to expand these known zones
Bert Monro,
Chief Executive Officer of Cora, commented,
"Given the size and geometry of the Tambor gold
anomaly, coupled with the promising first round drilling results,
this analysis work has further enhanced our understanding of the
significant gold mineralisation spread out over a large area within
the bedrock at Tambor. The results from the ICP-MS analysis have
further strengthened the Company's view that the current
exploration completed to date has literally only just scratched the
surface at Tambor. It's an exciting time for the Company to be
exploring in such a proven gold belt of the KKI and we look forward
to conducting further exploration to unlock the excellent
exploration potential at Tambor and deliver value to our
shareholders."
Figure 1.
Location map of
KKI, Tier 1 deposits and Cora Gold's Madina Foulbé exploration
permit
ICP-MS
PROGRAMME DETAILS
Background
To assist the Company in its understanding of
the Tambor gold anomaly and its future exploration efforts, all
drill samples (2,018) from the recently completed 39 hole
reconnaissance RC drill programme were submitted for ICP-MS (4 acid
digest) analysis at ALS Johannesburg. This data coupled with the
gold analyses has provided the Company with a large scientific
dataset to supplement previous gold only soil sampling
results.
The use of multi-element data is commonplace
within the exploration industry, particularly in weathered and
intrusive terrains such as Tambor. Some elements associated with
and dispersed around gold mineralisation may remain relatively
immobile and provide greater insight into the characteristics of
the mineralisation. ICP-MS (4 acids) is considered to the be
the industry gold standard for multi-element geochemical analysis,
as it provides a full suite of elements necessary to test key
relationships between lithology and mineralisation, alteration
styles and intensities, and the possible deposit type that hosts
the gold mineralisation.
A common exploration assumption is that gold in
soil anomalies generally doesn't accurately reflect gold
distribution in the bedrock; this is due to the oxidation of pyrite
(sulphides), which creates acid, causing the mobile elements such
as gold, silver ('Ag'), copper, lead, and zinc to be transported
during weathering. More insoluble elements in acid environment form
bonds with goethite (FeOH's) and are relatively immobile during
weathering. The immobile and path finder elements for gold in soils
are molybdenum ('Mo'), bismuth, tellurium ('Te'), arsenic, antimony
and tungsten. Multi-element data also provides unbiased results
especially with regards to lithology determination, which assists
greatly in understanding the full suite of lithologies present,
their spatial relationships and possible origins. This in turn
assists in understanding the possible deposit types and how best to
explore for these.
IMDEX's ioGAS software is an industry leading
software used to compile, display and interpret ICP-MS
multi-element results. Tambor's +2,000 RC drill samples generated
more than 80,000 data points requiring analysis and interpretation.
Interpretation of such large geochemical data sets often requires
expert knowledge. Accordingly, the Company secured the services of
industry renowned ioGAS expert and deposit specialist Dr. Nick
Oliver (HCOV Global). His knowledge and skill set has enabled the
Company to deliver these outcomes from the ICP-MS data.
Having completed the ICP-MS study work using
fresh and in-situ sample data, the results and their interpretation
are going to greatly assist the Company in its future exploration
at Tambor, especially in carrying out a multi-element soil
geochemical sampling programme from which the geochemistry data can
be interpreted more accurately. This will make any future drill
programme more focused at targeting the best in-situ gold
zones.
Study
Outcomes
1. Lithology Determination
Compared to the visual logging identification,
where 6 different lithology types were identified, analysis of
their geochemistry identified 12 different lithology units. Further
analysis showed that the felsic lithologies are highly
peraluminous, that the mafic and felsic rocks have very different
fractionation trends (see figure 2) and were derived from different
magmas, an important aspect in the geological environment at the
time of gold formation.
Figure 2.
Lithology type
graph (left) and magma fractionation profile (top
right). Note: SiO2 was estimated in ioGAS by the
difference from 100% by calculating all other elements as oxides,
and making a small allowance for H2O and other volatiles
lost during analysis. Open symbols on the left diagram are
interpreted as quartz vein-dominant
Confirming the 12 lithology types and plotting
their gold concentrations statistics (see figure 3) identified the
lithologies acting as the primary hosts to gold mineralisation.
This information, when coupled with their spatial location, has
provided the Company with a tool in which to target future
exploration at the higher-grade targets.
Figure 3.
Box and whisker
graph of Tambor's Lithologies and their Au ppm
statistics
2. Metal Associations
The reconnaissance drill programme targeted 10
distinct drill targets under the Tambor gold in soil anomaly. The
ICP-MS study showed that not all targets are the same, each target
has different concentrations and different associations of metals
associated with gold (see figure 4). Understanding the metals,
especially the immobile elements associated with gold, will greatly
assist the Company in understanding the results from future
multi-element soil geochemical sampling programmes at
Tambor.
Figure 4.
ICP-MS
multi-elements by drill target (1-10)
3. Alteration Types
The Tambor gold in soil anomaly is some 3km
long x 1.5km across (@ 20ppb Au). The recent RC drilling was
carried out at 10 targets within or surrounding the anomaly. ICP-MS
data from the 39 shallow RC drill holes drilled into the bedrock
was able to provide insight into the alteration types and their
zonation (see figure 5). Plotting the alteration data in 3-D space
highlighted the possible tops of deeper intrusives and temperature
gradients for use as a vector towards preferred sites for gold
deposition. Understanding possible temperature gradients with the
alteration types in conjunction with future multi-element soil
geochemistry and geophysical data (IP and Magnetics) will assist in
defining deeper high priority drill targets at Tambor.
Figure 5.
Graph of
Tambor's alteration types based on Na/Al versus K/Al
ratios
4. Deposit model
Based on 39 shallow RC drill holes and the
integration of all the available ICP-MS data and its analysis, it
was concluded that the Tambor mineralisation is likely an IRGS (as
denoted by its metal associations and Peraluminous Felsic intrusive
rocks) overprinting an earlier Orogenic gold system.
Key aspects that distinguish IRGS' are a strong
spatial association with (typically reduced) felsic to intermediate
intrusive rocks and a distinct metal association with low total
sulphides, but relatively high Bi-W-Sn +/-As-Sb-Mo. Orogenic gold
deposits can show some of this metal anomalism, but usually with a
more dominant As-Sb-S and a weaker spatial association with felsic
to intermediate intrusions. Due to the limited spatial coverage and
shallow nature of the recent drill programme, further work and
multi-element data is required over the entire Tambor area before
definitive conclusions can be made about the possible origins of
the gold mineralisation and its deposit type. Understanding and
classifying the possible deposit type greatly assists the Company
in understanding the likely deposit characteristics for future
exploration - i.e. IRGS deposits tend to have less sulphides
associated with gold as the gold precipitation mechanism usually
involves pressure and temperature decreases away from causitive
intrusions. Orogenic gold deposits commonly show a substantial
change in magnetic properties of the rocks because magnetite (in
mafic rocks or metasediments) is commonly converted to pyrite
during gold precipitation (by sulphidation), leaving a distinctive
geophysical signal.
5. Summary
This small data set of ICP-MS results and their
studies have provided valuable insights into the broader
understanding of the potential mineral system and its
characteristics present at Tambor. It is possible that the Tambor
Gold anomaly is related to an IRGS deposit, a common form of gold
deposit occurring around the world, but further work and data is
required before this can be conclusively proved. No possible
deposit analogies are being suggested at this stage for Tambor but
known IRGS systems include Morila (Mali); Donlin Creek-Fort
Knox-Pogo (Yukon / Alaska); and Kidston (Australia), which are all
examples of economic multi-million ounce deposits.
IRGS deposits tend to have subtle surface or
geophysical signatures and may be more difficult to explore as a
result. However, due to the circulation of magmatic fluids
surrounding the intruding intrusives, zonation of metal based on
temperature gradients may act as a vector towards the centre of the
intrusives and / or preferred zones hosting gold
mineralisation.
Due to the 2-D nature of the drilling (as
fences) and irregular locations under the massive Tambor gold in
soil anomaly, it isn't possible at this stage to use the ICP-MS
results as an immediate drill targeting tool. Further surface
multi-element data, IP and magnetic surveys are required to focus
and direct any future drilling programmes.
To achieve in-situ bedrock drill results such
as 10m @ 4.41 g/t Au from 41m in hole MFC0013 at Target 1, 16m @
0.97 g/t Au from 38m in hole MFC0014 at Target 1, 29m @ 0.71 g/t Au
from 1m in hole MFC0021 at Target 9, and 19m @ 0.61 g/t Au from 34m
in hole MFC0049 at Target 8, based on drill targeting from gold in
soil values (likely remobilised) is indicative of the large
underlying mineralised system present at Tambor. The Company
requires more data from geophysical surveys and multi-element soil
data, to build a better spatial and geological model of the likely
gold distribution and controls at depth, in order to generate
greater drilling success in this large gold rich system.
Competent
Person's Statement
The technical information in this release was
reviewed and approved by Mr. Murray Paterson in his capacity as a
Competent Person, in accordance with the guidance note for Mining,
Oil & Gas Companies issued by the London Stock Exchange in
respect of AIM Companies, which outlines standards of disclosure
for mineral projects. Mr. Paterson is Cora's Head of Geology and is
a member of good standing with the Australasian Institute of Mining
and Metallurgy (MAusIMM). Mr. Paterson has sufficient experience
that is relevant to the style of mineralisation and type of deposit
under consideration, and to the activity which he is undertaking,
to qualify as a Competent Person as defined in the 2012 Edition of
the 'Australasian Code for Reporting of Exploration Results,
Mineral Resources and Ore Reserves'. Mr. Paterson consents to the
inclusion in this release of the Exploration Results in the form
and context in which it appears.
Market Abuse
Regulation ('MAR') Disclosure
Certain information contained in this
announcement would have been deemed inside information for the
purposes of Article 7 of the Market Abuse Regulation (EU) No
596/2014 ('MAR'), which is part of UK law by virtue of the European
Union (Withdrawal) Act 2018, until the release of this
announcement.
**ENDS**
For further information, please visit http://www.coragold.com, follow us on
social media (LinkedIn and X: @cora_gold) or contact:
Bert Monro
Craig Banfield
|
Cora Gold Limited
|
info@coragold.com
|
Derrick Lee
Pearl Kellie
|
Cavendish Capital Markets Limited
(Nomad & Broker)
|
+44 (0)20 7220 0500
|
Susie Geliher
Isabelle Morris
Charlotte Page
|
St Brides Partners
(Financial PR)
|
cora@stbridespartners.co.uk
|
Notes
Cora is a West African gold developer with
de-risked project areas within two known gold belts in Mali and
Senegal. Led by a team with a proven track-record in making
multi-million-ounce gold discoveries that have been developed into
operating mines, its primary focus is on developing the Sanankoro
Gold Project in the Yanfolila Gold Belt, south Mali, into an open
pit oxide mine. Based on a gold price of US$1,750/oz and a Maiden
Probable Oxide Reserve of 422koz at 1.3 g/t Au, the Project has
strong economic fundamentals, including 52% IRR, US$234 million
Free Cash Flow over life of mine and all-in sustaining costs of
US$997/oz. Alongside this, the Company continues to seek value
opportunities across its portfolio and has identified large scale
gold mineralisation potential at the Madina Foulbé exploration
permit within the Kenieba Project Area of east Senegal.