Panthera Resources PLC Kalaka Metallurgical Test Results

RNS Number : 3301S

Panthera Resources PLC

13 June 2024

 

13 June 2024

Panthera Resources Plc

("Panthera" or "the Company")

 

Kalaka Metallurgical Test Results

 

Panthera Resources Plc (AIM: PAT), the diversified gold exploration and development company with assets in West Africa and India, is pleased to announce the results for bottle roll metallurgical tests on samples of crushed diamond drill core.

 

Highlights

·        These test results showed recoveries between 67% and 88%, a positive result for the coarse size tested (minus 10mm).

·        All samples tested show relatively fast cyanide leaching with most gold extracted within 12 hours of leaching.

·        The initial tests show an ore amenable to simple cyanide leaching and build on previous encouraging Leachwell analysis¹ which also returned positive cyanide extractable gold recovery results.

 

Commenting on the results, Mark Bolton, Managing Director of Panthera said:

 

"The positive results from this metallurgical testing together with the previously reported favourable Leachwell test results further underpin our growing confidence in the potential at Kalaka which is a significant mineralised gold system.  

 

This testing represents another important step in our multi-step approach towards assessing the potential for Kalaka mineralisation to be developed by heap leach processing.  If this and future work confirm this approach to be viable, the body of work will demonstrably lift confidence in the Kalaka mineralisation to be able to be economically developed."

 

Bottle Roll Cyanide Leach Metallurgical Test Work

 

The Company engaged metallurgist Ray Burring of 4 Dragons Gold Pty Ltd to advise on the test design and interpretation of the test results.

 

The objective of this testing was to provide further metallurgical data on the sulphide leach performance of the Kalaka mineralisation, as one of the steps in our overall plan to assess the potential for this mineralisation to be developed by heap leach processing.

 

A cyanide bottle roll test is the industry standard first step in assessing the gold recovery possible by cyanide leaching. During a bottle roll test, prepared ore is gently agitated in a cyanide lixiviant or leaching solution and usually analysed at various leach time intervals.

 

It is cautioned that although these initial tests show an ore amenable to simple cyanide leaching, further bench scale testing will be required of various sizes in columns to simulate leaching in a heap scenario and bench testing using material ground to -75 microns be completed to determine the recovery potential in a carbon in leach (CIL) plant to evaluate the metallurgical properties of the ore.

 

The samples were taken over one metre intervals of available quarter core from two of the historical diamond drill holes at the K1A Prospect. The core samples were submitted to the SGS Laboratory located in Bamako, Mali and crushed to a minus 10mm size, under supervision of Panthera staff.  The metallurgical testing was completed by SGS Ouagadougou in Burkina Faso.

 

The following summarizes key aspects of the process method used:

·        tests were completed on 14 one metre interval quarter core samples where each sample weighed 2kg or less;

·        the samples of drill core were crushed to a nominal 10mm;

·        Each entire sample was treated by bottle rolling in cyanide liquor, wherein aliquots are drawn off after time intervals of 2, 12, 24 and 48 hours, and assayed by AAS for gold contents; and

·        The residue is then Fire Assayed² for gold content after the 48 period, a head grade is calculated from these results and all time-determined recoveries calculated and reported.

 

Results and Observations of Bottle Roll Metallurgical Testing.

 

Presented in Table 1 below is a summary of the SGS Burkina SA analytical report with sample descriptions contained in the Appendix.

 

The tests were carried at 50% solids by weight, as per normal practice, and the head grade calculated from the addition of the assay at the end of the test (48 hours) and the tailings residue.  The results from samples KA-Met-24 numbers 007 to 020 were split into low calculated head grades < 1ppm and calculated head grades >1ppm.

 

TABLE 1.

 

Samples Crushed to <10mm
Low Grade <1 ppm
	Calc Head Grade	Tails Grade	Au Rec'y at 2 hrs	Au Rec'y at 12 hrs	Au Rec'y at 24 hrs	Au Rec'y at 48 hrs
KA-MET-24-007	0.794	0.16	75.1%	76.2%	76.4%	79.8%
KA-MET-24-011	0.995	0.13	69.0%	76.5%	82.6%	86.9%
KA-MET-24-012	0.445	0.10	74.8%	74.2%	75.3%	77.5%
KA-MET-24-015	0.647	0.14	74.0%	76.5%	77.3%	78.4%
KA-MET-24-018	0.554	0.15	71.3%	70.4%	74.2%	72.9%
KA-MET-24-019	0.554	0.16	66.2%	67.1%	69.7%	71.1%
KA-MET-24-020	0.457	0.07	77.9%	77.5%	84.0%	84.7%
Grade >1 ppm
	Calc Head Grade	Tails Grade	Au Rec'y at 2 hrs	Au Rec'y at 12 hrs	Au Rec'y at 24 hrs	Au Rec'y at 48 hrs
KA-MET-24-008	1.075	0.17	80.5%	82.0%	82.6%	84.2%
KA-MET-24-009	1.379	0.30	75.7%	77.7%	77.7%	78.2%
KA-MET-24-010	1.167	0.23	70.2%	76.4%	79.4%	80.3%
KA-MET-24-013	1.276	0.15	79.0%	83.4%	84.9%	88.2%
KA-MET-24-014	3.750	0.55	70.4%	79.3%	82.9%	85.3%
KA-MET-24-016	1.995	0.65	62.5%	59.6%	66.6%	67.4%
KA-MET-24-017	4.016	0.90	71.9%	71.8%	76.2%	77.6%

 

Discussion

·        Samples were from core crushed to <10mm.

·        The recoveries from the low grade <1ppm samples were all acceptable showing low tailings grades and could be extracted using heap leach techniques.

·        The recoveries from the higher grades >1ppm were all relatively good for coarse material crushed to <10mm. The higher grades showed high tailings grades, as would be expected. To possibly improve on these test results in following steps towards assessing applicability of heap leach processing, such higher grade samples would be crushed and ground to much finer sizes and higher recoveries can be expected.

·        The recoveries ranged from 67% to 88%. These are interpreted as good recoveries for material crushed <10 mm.

·        All samples tested show relatively fast leaching with most of the gold extracted after 12 hours of leaching.

 

Conclusions

·        The samples of low grade from the crushed samples achieved reasonable recoveries with low tailings grades.

·        The samples of the higher grades from the crushed samples gave good recoveries for coarse material.

 

Kalaka Project Background

 

At the Kalaka Project, Panthera has an 85% joint venture interest with the remaining 15% interest held by our local partner, Golden Spear Mali SARL. Panthera is the operator of the project.

 

The project is located in southeast Mali, between Morila and Syama gold mines and is approximately 260 km southeast of Bamako. It lies approximately 80 km south of the Morila gold mine (8m oz) and 85 km northwest of Resolute's Syama gold mine (6m oz) and is situated adjacent and to the east of the regional Banifin Shear Zone.

 

At the K1A target area, the Company's Competent Person Report (prepared by Golder Associates Pty Ltd), which was disclosed in the Company's AIM Admission Document, reported that drilling by past explorers defined a potential endowment of 250,000 to 500,000 ounces. Furthermore, Golder Associates Pty Ltd ("Golder") reported that this represents an exploration target where further infill drilling may lead to the estimation of a Mineral Resource.

 

More recently, follow-up work by Panthera including re-examination of all available drill data at K1A, identified a mineralised envelope that broadly conforms to the potential endowment mentioned by Golder. This work identifies an exploration target of between 0.5 Moz to 1 Moz gold.  Importantly, the Company is yet to drill the northern extension of the mineralisation at K1A together with several similar targets on the project area. Taken together this would potentially expand the exploration target to approximately 3 Moz of gold.

 

Notes:

1.         The Leachwell analytical technique is formulated for treating large samples, typically plus 2kg weight, by fast cyanide ("CN") leach gold analysis. The technique provides a preliminary indication of the CN leachability of pre-metallurgical sample testing. As Leachwell analysis is carried out on larger samples (typically 2 kg or more in weight it can be considered representative of gold content especially when particle gold may occur. After the CN gold leaching cycle has been completed the CN solution is analysed. The 'tails' after the gold extraction by the CN method are then processed using fire assay technique to identify the residual content of gold in the sample.

2.         Fire assay method has been practiced since ancient times and remains the industry-standard technique for determining gold content in all sample types. This well-understood technique provides accurate results across geological sample types. However, practiced skill is essential to achieving a successful fire assay. A range of fire assay methods are available with 30g or 50g sample aliquots taken after a larger representative sample has been crushed and pulverised for homogenisation. Multiple options for detection ranges to suit the needs of the project.

 

APPENDIX - Sample Description and Analytical Data

 

 

Contacts

 

Panthera Resources PLC Mark Bolton (Managing Director)	[phone] [e-mail]
Allenby Capital Limited (Nominated Adviser & Joint Broker)                                                                                                        John Depasquale / Vivek Bhardwaj (Corporate Finance)       Guy McDougall / Kelly Gardiner (Sales & Corporate Broking	[phone]
Novum Securities Limited (Joint Broker)	[phone]
Colin Rowbury

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Qualified Persons

The technical information contained in this disclosure has been read and approved by Ian S Cooper (BSc, ARSM, FAusIMM, FGS), who is a qualified geologist and acts as the Qualified Person under the AIM Rules - Note for Mining and Oil & Gas Companies.  Mr Cooper is a geological consultant to Panthera Resources PLC.

 

The technical information contained in this disclosure relating to the metallurgical test work has been read and approved by Ray Burring. Ray is the owner and principal engineer of the Consulting Company, 4 Dragons Gold Pty Ltd, that has operated since 1989. Ray has a degree in Mineral Processing from Leeds University and is a Member of the Australian Institute of Mining and Metallurgy, Member of the Institute of Materials, Minerals and Mining and a Chartered Engineer. Ray is a Metallurgist with extensive experience of Gold and Base Metal operations, both operating and design. This work has been carried out in Australia, Vietnam, Laos, New Zealand, France, Iran, Mauritania, Russia and Eritrea. Ray Burring acts as the Qualified Person under the AIM Rules - Note for Mining and Oil & Gas Companies.  Mr Burring is a Metallurgical consultant to Panthera Resources PLC.

 

UK Market Abuse Regulation (UK MAR) Disclosure

The information contained within this announcement is deemed by the Company to constitute inside information for the purposes of Regulation 11 of the Market Abuse (Amendment) (EU Exit) Regulations 2019/310. Upon the publication of this announcement via a Regulatory Information Service ("RIS"), this inside information is now considered to be in the public domain.

 

Forward-looking Statements

This news release contains forward-looking statements that are based on the Company's current expectations and estimates. Forward-looking statements are frequently characterised by words such as "plan", "expect", "project", "intend", "believe", "anticipate", "estimate", "suggest", "indicate" and other similar words or statements that certain events or conditions "may" or "will" occur. Such forward-looking statements involve known and unknown risks, uncertainties and other factors that could cause actual events or results to differ materially from estimated or anticipated events or results implied or expressed in such forward-looking statements. Such factors include, among others: the actual results of current exploration activities; conclusions of economic evaluations; changes in project parameters as plans continue to be refined; possible variations in ore grade or recovery rates; accidents, labour disputes and other risks of the mining industry; delays in obtaining governmental approvals or financing; and fluctuations in metal prices. There may be other factors that cause actions, events or results not to be as anticipated, estimated or intended. Any forward-looking statement speaks only as of the date on which it is made and, except as may be required by applicable securities laws, the Company disclaims any intent or obligation to update any forward-looking statement, whether as a result of new information, future events or results or otherwise. 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.

 

 

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