Cora Gold Limited Multi-element analysis at Madina Foulbé

RNS Number : 0578H

Cora Gold Limited

07 October 2024

 

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	[e-mail]
Derrick Lee Pearl Kellie	Cavendish Capital Markets Limited (Nomad & Broker)	[phone]
Susie Geliher Isabelle Morris Charlotte Page	St Brides Partners (Financial PR)	[e-mail]

 

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.

This information is provided by RNS, the news service of the London Stock Exchange. RNS is approved by the Financial Conduct Authority to act as a Primary Information Provider in the United Kingdom. Terms and conditions relating to the use and distribution of this information may apply. For further information, please contact [e-mail] or visit www.rns.com.

RNS may use your IP address to confirm compliance with the terms and conditions, to analyse how you engage with the information contained in this communication, and to share such analysis on an anonymised basis with others as part of our commercial services. For further information about how RNS and the London Stock Exchange use the personal data you provide us, please see our Privacy Policy.

 

END

 

 

MSCBUBDGLDGDGSS