Update on Metallurgical Test Work Results
The information contained within this announcement is deemed by the Company to constitute inside information as stipulated under the Market Abuse Regulations (EU) No. 596/2014 ("MAR")
Kodal Minerals Plc / Index: AIM / Epic: KOD / Sector: Mining
20 August 2019
Kodal Minerals plc ('Kodal Minerals' or the 'Company')
Positive Metallurgical Test Work Results at Bougouni Lithium Project, Mali
Kodal Minerals, the mineral exploration and development company focused on its Bougouni Lithium Project in southern Mali (the 'Project', 'Bougouni' or the 'Bougouni Project'), is pleased to provide an update on the extensive metallurgical test work programmes carried out on mineralisation at the Bougouni Project. The test work programmes have been undertaken as part of the Company's feasibility assessment and will be used to complete the process flowsheet for the proposed mining operation.
Highlights:
· Metallurgical test work demonstrates initial processing via a Dense Media Separation ('DMS') plant, with a flotation circuit to be added to improve overall recoveries if required.
· DMS test work on the Ngoualana Prospect mineralisation returned primary concentrate grades of 6.0% Li2O at recoveries of up to 70%.
· A master composite comprising 70% Sogola-Baoulé and 30% Ngoualana tested initially with the DMS circuit was followed by downstream flotation test work which improved overall recovery to 75%, producing a 6.0% grade Li2O concentrate.
· Metallurgical test work will continue on the Boumou mineralisation and additional testing on the Sogola-Baoulé mineralisation will define additional coarse grained DMS ore.
Bernard Aylward, CEO of Kodal Minerals, remarked: "The various metallurgical test works carried out over the Project area have highlighted the importance of the coarse grained Ngoualana mineralisation. The identification of this ore type has influenced how we will plan for the development of the Bougouni Lithium Project as now we are aware that we can commence with a low upfront capital cost solution of initial DMS testing, with the deferred addition of a flotation processing circuit to improve recoveries when required.
We are continuing to advance our Bougouni Project with this metallurgical test work programme being undertaken in conjunction with both the engineering studies to optimise the potential open pit mining operations, as well as the planning of the transport and logistical support for the Project. I look forward to updating shareholders with further developments as we continue to make progress towards completing a Feasibility Study at Bougouni."
Further Information
Metallurgical Test Work Programmes
A metallurgical test work programme was established to test both conventional DMS and flotation circuit recoveries at the Bougouni Lithium Project, in support of the Feasibility Study. DMS test work via laboratory scale heavy liquid separation ('HLS') was initially performed on the first pegmatite mineralisation discovery at the Ngoualana deposit, to provide sighter test work results to support the more extensive Feasibility Study programme.
Metallurgical Sighter Test Work
A coarse crush size for the initial DMS sighter test work completed in 2018 of P100 12.5mm was selected to provide guidance for feasibility level follow-up work. The results from this first Ngoualana composite sample HLS test work with head grade of 1.42% showed encouraging results from the very coarse crush size, indicating an overall DMS recovery of 49.8% at a grade of 4.3% Li2O.
Analysis of the sighter test work indicated that a reduction in crush size from P100 12.5mm to nominal crush size of 6.30mm would result in an increased spodumene liberation into the finer size fractions, resulting in higher overall DMS recoveries and concentrate grades. The finer crush size would, however, result in an increase in spodumene reporting to the smaller size fractions, potentially justifying downstream flotation processing to upgrade concentrate grade and recoveries.
Feasibility Study Master Composite DMS Test Work
On the basis of the sighter test work results, Kodal commissioned Independent Metallurgical Operations ('IMO') in Perth, Western Australia, to carry out the Feasibility Study DMS HLS test work programme. Intervals for preparation of a master composite were selected across multiple diamond drill holes to spatially cover both the Sogola-Baoulé and Ngoualana deposits. As well as spatial distribution across both resources, the master composite was selected at a 70:30 ratio respectively, based on replicating the Indicated JORC Resource estimate distributions.
The master composite was crushed to P100 12.5mm and subsequently homogenised and split; these sub splits were then crushed to a P100 of 8.00mm and 6.30mm respectively. Both crush sizes were size by size assayed at 7 and 8 screen sizes respectively. The assay produced a head grade of 1.36% Li2O, and low Fe2O3 grade of 0.81%.
Crushed samples were subjected to HLS test work at variable SGs of 2.80, 2.85, 2.90 and 2.96. Laboratory test results for the -6.3mm crushed product are tabulated below which includes the recovery to achieve a 6% Li2O concentrate grade for each size fraction, and overall.
Table 1 -6.30mm Cumulative Stage Master Composite HLS Test Work Summary
|
|
SG Cut |
Total |
-6.30+3.35mm |
-3.35+1.18mm |
-1.18+0.85mm |
-0.85+0.50mm |
-0.50+0.0mm |
|
|
kg/L |
% |
% |
% |
% |
% |
% |
|
Mass Dist' |
|
|
50.69 |
26.43 |
4.46 |
5.09 |
13.33 |
|
Cumulative Li2O Grade |
0 |
1.38 |
1.47 |
1.29 |
1.23 |
1.18 |
0.96 |
|
2.8 |
4.52 |
4.19 |
4.81 |
5.49 |
5.81 |
|
|
|
2.85 |
5.26 |
4.93 |
5.48 |
5.97 |
6.18 |
|
|
|
2.9 |
5.83 |
5.54 |
5.96 |
6.29 |
6.48 |
|
|
|
2.96 |
6.26 |
6.03 |
6.34 |
6.57 |
6.63 |
|
|
|
Cumulative Li2O Recovery |
0 |
90.38 |
100.00 |
100.00 |
100.00 |
100.00 |
9.62 |
|
2.8 |
53.35 |
53.49 |
64.55 |
76.44 |
80.56 |
|
|
|
2.85 |
40.20 |
36.64 |
52.20 |
69.43 |
75.16 |
|
|
|
2.9 |
31.90 |
26.47 |
43.95 |
63.19 |
70.18 |
|
|
|
2.96 |
26.56 |
20.40 |
37.78 |
58.40 |
66.68 |
|
The results presented in Table 1 indicate the following:
· For the master composite sample, a Li2O grade and recovery of 6.26% and 26.6% respectively at a 2.96 SG cut point from the -6.30 +0.50mm size fraction;
· An increase in recovery to approximately 30% lead to a decrease in Li2O grade to 6.0%;
· As the particle size fraction tested decreased, so too did the recovery to a 6.00% Li2O grade concentrate, which indicates that spodumene liberation improved with decreasing particle size; and
· Excellent liberation was demonstrated for particles coarser than 0.5mm with >60% recovery to 6.00% Li2O grade for particles in the 1.18 to 0.5mm fractions.
Feasibility Study Variability Samples DMS Test Work
The original sighter test work showed higher recoveries from HLS test work than was observed from the master composite results tabulated above (Table 1). The original sighter test work was conducted only on Ngoualana material, indicating that the coarser pegmatite grain structure at Ngoualana (as compared with the finer grains observed at Sogola-Baoulé and Boumou), is more amenable to DMS processing.
The master composite test work was followed up with four variability samples for separate HLS testing of Ngoualana and Sogola-Baoulé materials. This work was conducted in an effort to determine whether the unliberated spodumene in the master composite was attributable predominantly to Sogola-Baoulé.
The four variability samples as described below were generated to represent four areas of the two ore bodies and assayed using the same method as per the master composite.
· Variability 1 (V1) represents the deep section of the Sogola-Baoulé prospect -
head grade of 1.91% Li2O, and low Fe2O3 grade of 0.77%;
· Variability 2 (V2) represents the shallow section of the Sogola-Baoulé prospect -
head grade of 1.19% Li2O, and low Fe2O3 grade of 0.57%,
· Variability 3 (V3) represents the low-grade areas of the Ngoualana prospect -
head grade of 1.08% Li2O, and low Fe2O3 grade of 0.75%; and
· Variability 4 (V4) represents high grade material within the Ngoualana prospect -
head grade of 1.96% Li2O, and low Fe2O3 grade of 0.52%.
All four variability samples were subjected to a similar testing regime as the master composite in order to maintain comparability. The results for the Ngoualana variability testing are highlighted below.
Table 2 -6.30 mm Cumulative Stage V4 Ngoualana HLS Test Work Summary
|
|
SG Cut |
Total |
-6.30+3.35 |
-3.35+1.18 |
-1.18+0.85 |
-0.85+0.50 |
-0.50 mm |
|
|
kg/L |
% |
% |
% |
% |
% |
% |
|
Mass Dist' |
|
|
29.69 |
33.69 |
7.19 |
8.18 |
21.25 |
|
Cumulative Li2O Grade |
0 |
0.41 |
0.67 |
0.34 |
0.16 |
0.14 |
1.19 |
|
2.8 |
3.32 |
3.40 |
3.33 |
2.50 |
2.50 |
|
|
|
2.85 |
4.10 |
4.11 |
4.09 |
4.18 |
4.18 |
|
|
|
2.90 |
4.67 |
4.68 |
4.61 |
4.95 |
4.95 |
|
|
|
2.96 |
6.62 |
6.27 |
6.63 |
7.30 |
7.30 |
|
|
|
Cumulative Li2O Recovery |
0 |
11.11 |
16.22 |
11.27 |
6.83 |
7.04 |
13.09 |
|
2.8 |
6.69 |
11.76 |
5.35 |
2.59 |
2.17 |
|
|
|
2.85 |
5.28 |
8.16 |
5.19 |
2.57 |
2.32 |
|
|
|
2.90 |
8.81 |
13.99 |
8.12 |
4.78 |
4.14 |
|
|
|
2.96 |
55.02 |
49.86 |
70.07 |
83.24 |
84.33 |
|
The results of the variability test work indicate:
· HLS recoveries are higher for Ngoualana samples when compared to Sogola-Baoulé, supporting the premise that the former is more amenable to DMS processing;
· Ngoualana V4 (Table 2) provided best results with Li2O grade and recovery of 6.62% and 55.0% respectively at a 2.96 SG cut point for -6.30 +0.50mm size fractions;
· The trend of significant improvements in liberation as the particle size decreases from -6.30mm to -3.35mm is consistent across all samples tested, although Ngoualana material is demonstrably coarser grained compared to Sogola-Baoulé; and
· The Ngoualana material is amenable to up front DMS processing, with the addition of downstream flotation processing likely to improve overall recoveries from all deposits, justifying the decision to progress a flotation test work programme as outlined below.
Feasibility Study Flotation Test Work Programme
On the basis of the HLS test work results above, Kodal commissioned Nagrom the Mineral Processor ('Nagrom') in Perth, Western Australia, to carry out the Feasibility Study flotation test work programme. The programme was supervised by the Feasibility Study plant engineering consultant, DRA Global (formerly Minnovo Pty Ltd) in Perth.
The master composite created for the DMS work was also used for the flotation development programme. Therefore, it also represented a 70:30, Sogola-Baoulé : Ngoualana, ratio. The assay produced a head grade of 1.27% Li2O, and low Fe2O3 grade of 0.57%.
The master composite was stage crushed to P100 3.35mm, from which samples were blended and split for up-front head grade analysis, grind establishment, moisture determination, cyclone setup and cut-point establishment, followed by multi-stage flotation test work. It is noted that this test work was not conducted on spent HLS samples, but with fresh samples unaffected by upstream test work.
A conservative grind size P80 106 microns was selected as feed to the flotation circuit. The flotation test work included three stages of feed preparation (desliming, magnetic separation and mica pre-float) to simulate lithium processing plant conditions. DRA Global has recent experience at similar DMS and flotation processing facilities in Western Australia, which demonstrate that opportunity exists to coarsen the grind size.
The programme demonstrated that the target final concentrate quality of 6% Li2O can be achieved using three stages of flotation (roughing and two stages of cleaning), once the ore has been effectively prepared by: rejection of slime particles (-20 micron), magnetic particles removal (via magnetic separation) and mica removal.
The results of the laboratory test work demonstrated that the Bougouni Lithium Project can achieve a 6% Li2O concentrate grade at 75% Li2O recovery with respect to feed.
Summary of the Metallurgical Test Work Programme
Overall, the results of the metallurgical test work programme were very encouraging, confirming Ngoualana ores are amenable to simple, convention DMS processing, with further upgrade in recoveries possible using downstream flotation processing for all materials, to produce a saleable Li2O grade with recoveries in the order of 75%.
Forward Work Plan
DRA Global will utilise the results of the test work programme to finalise the Feasibility Study process flowsheet for upfront DMS processing of Ngoualana ores, followed by downstream flotation processing. The design concept for the Bougouni Lithium Project will be to defer installation of the flotation circuit to reduce upfront capital costs, given Ngoualana material is amenable to DMS only processing.
**ENDS**
For further information, please visit www.kodalminerals.com or contact the following:
|
Kodal Minerals plc Bernard Aylward, CEO |
Tel: +61 418 943 345
|
|
Allenby Capital Limited, Nominated Adviser Jeremy Porter/Nick Harriss
|
Tel: 020 3328 5656 |
|
SP Angel Corporate Finance LLP, Financial Adviser & Broker John Mackay
|
Tel: 020 3470 0470 |
|
St Brides Partners Ltd, Financial PR Catherine Leftley/Cosima Akerman
|
Tel: 020 7236 1177 |
About Kodal Minerals
Kodal Minerals' primary focus is on the rapid advancement towards production of its flagship Bougouni Lithium Project in Southern Mali. The JORC Resource Estimate places the Bougouni Project in the top 15 hard rock lithium projects globally and was calculated using only three of the eight currently recognised prospects demonstrating the significant exploration upside potential remaining across the 450km2 project area. The Mineral Resource estimate for the Ngoualana, Sogola-Baoule and Boumou prospects are tabulated below. These mineral resources are reported in accordance with the JORC Code:
|
Prospect |
Indicated |
Inferred |
Total |
||||||
|
Tonnes (Mt) |
Li2O% Grade |
Contained Li2O (kt) |
Tonnes (Mt) |
Li2O% Grade |
Contained Li2O (kt) |
Tonnes (Mt) |
Li2O% Grade |
Contained Li2O (kt) |
|
|
Sogola_ Baoulé |
8.4 |
1.09 |
91.9 |
3.8 |
1.13 |
42.8 |
12.2 |
1.10 |
134.8 |
|
Ngoualana |
3.1 |
1.25 |
39.2 |
2.0 |
1.12 |
22.1 |
5.1 |
1.20 |
61.3 |
|
Boumou |
|
|
|
4.0 |
1.02 |
40.4 |
4.0 |
1.02 |
40.4 |
|
TOTAL |
11.6 |
1.13 |
131.2 |
9.7 |
1.08 |
105.3 |
21.3 |
1.11 |
236.5 |
Note: Mineral resources are reported using a 0.5% Li2O cut-off. Figures may not sum due to rounding. The contained metal is determined by the estimated tonnage and grade.
The Bougouni Project and recently acquired 200km2 Bougouni West project are located in an emerging lithium province that is already attracting the attention of investors and off-take partners interested in securing a long-term supply of lithium. With the support of its strategic investor and off-take partner Suay Chin International Pte, a Singapore-based lithium and chemical trader, Kodal Minerals is well placed to continue its ambitious development programme at Bougouni.
Further to this, Kodal Minerals is the manager of additional lithium and gold projects that are undergoing low cost exploration programmes in addition to JV funded gold properties in Côte d'Ivoire that offer potentially significant long-term value.
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