BWA Group Plc - Findings of Testwork at the Nkoteng 1 Heavy Mineral Sands Project
Announcement provided by
BWA Group plc · BWAP19/07/2023 07:00
Findings of Orientation Mineral Separation Testwork at the Nkoteng 1 Heavy Mineral Sands Project,
19 July 2023
BWA Group PLC
(“BWA”, or the “Company”) (AQSE: BWAP)
Findings of Orientation Mineral Separation Testwork at the Nkoteng 1 Heavy Mineral Sands Project,
BWA Group plc [AQSE: BWAP], which has mineral exploration licences in both
Through its subsidiary, BWA Resources Ltd (“BWAR”), BWA currently has five heavy mineral sands (“HMS”) licences across two project areas in
A version of this announcement including maps and photographs can be viewed on the Company’s website, http://www.bwagroupplc.com/bwa-announcements.html
BWA is pleased to announce the findings of the preliminary orientation mineral separation testwork on selected low-grade samples taken from the closed barrel mechanised auger sampling programme on the Nkoteng 1 Project, reported in accordance with JORC (2012). The short shallow auger sampling programme completed in June 2022 drilled 107 holes for 193.30 metres and 171 primary samples (announcement dated 29 June 2022). The programme targeted the central sector of the licence where pitting and hand auger sampling (announcement dated 29 June 2022) identified an area of anomalous Ilmenite, Rutile, Zircon and Kyanite alluvial HMS.
The orientation analytical testwork was completed by Dipl. Ing. Uwe Bruder of Bruder Consulting Germany and comprised processing of 20 low-grade auger drill cores, composited for test work (Table 1) using simple process methods and equipment including gravity, sluice, heavy liquid and magnetic separation. A primary objective of the work to determine suitable process design and procedures for use in
The scope of works entailed:
- Compositing auger samples into 3 similar unit types (clay, sand, weathered clay).
- Orientation mineral separation processing and analytical testwork.
- Approximate recovery of heavy minerals using simple process equipment.
- Proposals for simple methods to determine the preferred analytical method for in-country analysis of heavy minerals from drill cores (equipment and test procedure).
Highlights and Commentary
Although the samples were low-grade and from areas that BWA consider to be of lower prospectivity and priority, the samples have returned positive and anomalous results. The testwork methodology and subsequent analytical flowsheet was the important aspect and deliverable of the testwork which will lead into onsite laboratory design and Standard Operating Procedures.
Test work demonstrated good recovery (>80%) of heavy minerals by simple gravity, DMS and magnetic separation within the sand size samples of the material provided. As expected, the sand composite sample contain the greatest quantity of HMS. However significant heavy minerals do occur within clay size samples, and not unexpectedly these are less easily separated, requiring additional sluice processing.
A breakdown of total heavy mineral (“THM”) content from the composite samples are as follows:
>0.063 mm sample fraction (sand particle size and above):
- Clay composite sample – 0.35% THM
- Sand composite sample – 0.824% THM
- Weathering clay composite sample – 0.639% THM
<0.063 mm sample fraction (clay particle size):
- Clay composite sample – 0.408% THM
- Sand composite sample – 1.350% THM
- Weathering clay composite sample – 0.245% THM
It should be noted, the highly prospective coarse basal gravels primary target unit have not been encountered or tested as part of this study.
Outlook
The Company are processing the orientation testwork results to understand the implications. Furthermore, the results will be combined with the size fractioning studies completed in September 2022 to identify the relationships and add more information to improve the knowledge of the depositional characteristics for Nkoteng and associated licences.
This orientation testwork will lead into onsite laboratory design and Standard Operating Procedures with work in progress to source suppliers and equipment, in preparation for the planned exploration programme.
The THM% content from the samples is encouraging from low-grade areas and is reasonable from within the sand size fractions. Furthermore, recovery appears to be good from observations by Bruder Consulting from the shaking table and sluices, with recoveries indicated around 80%.
James Butterfield, interim Non-executive Chairman of BWA, commented:
“This round of orientation testwork has given BWA a clear process to follow in order to set up an in-country laboratory, as well as working towards a set of Standard Operating Procedures with which to work within, ensuring accurate and reliable analysis. BWA are also pleased with the early indications of recovery using lab-scale methods. More work is required in the future. BWA is excited about the positive outcome and is planning further exploration from the Nkoteng and Dehane sites”.
Summary of Orientation Mineral Separation Testwork
In accordance with JORC (2012) reporting guidelines, a summary of the material information used is set out below. For further details, please refer to the JORC (2012) Table 1, located in the Appendix to this announcement.
The exploration programme from which the 20 primary samples were selected, consisted of 107 holes for 193.30 metres and 171 primary samples, collected within the current and paleo Sanaga river floodplain (Figure 2). The holes were mechanically drilled using a Van Walt windowless percussion sampling system with half core samples split for analysis, with the remaining half core stored in bags for reference and duplicate samples as necessary.
The 20 primary samples were composited into three lithological groups: clay, sand, and weathering clay which were tested separately, as presented in the table below and in Figure 3. The colours denominate the composite, those without colours were excluded and deemed outliers to primary lithology types. The test steps are outlined below and illustrated in Figure 3:
- PSD (particle size distribution) work on 100 grams of sample (Table 2).
- Crushing down to <6.0mm.
- Agitation of each sample in water until the clayey agglomerates had dissolved.
- Gravity sorting by shaking table (> 0.063 mm fractions) and sluice (< 0063 mm) (Figure 4 and 5). Although possible to recover below 0.063 mm, it would likely not be economic on an industrial scale.
- Drying of preconcentrates for dry magnetic separation.
- Magnetic separation for magnetic minerals, i.e., ilmenite and non-magnetic minerals, i.e., rutile and zirconium
- Heavy liquid separation (2.82 g/cm³) of magnetic and non-magnetic separation products.
- Reporting (Figure 6 and 7 and Table 2).
Geology and Geological Interpretation
The prospective Sanaga river is the main river which runs through the BWA Nkoteng 1 and 2 licence area and accommodates approximately 100 km of the river floodplain system and associated tributaries, and an even larger paleo-floodplain area, observed in satellite imagery, although this has yet to be fully ground-truthed through fieldwork.
The geological sequence generally consists of a cover of clays, overlying the target deposit layer consisting of sands and gravels, generally laying directly on the bedrock.
Surficial geology encountered during the auger programme comprised of 0.2 m of surface organic rich soil, alluvial clays and sandy clays ranging from 0 m to 4 m with an average thickness of approximately 1.3 m thick, and basal sand and gravels ranging from 0 m to 3 m thick in places.
The Nkoteng deposit is likely to be a trap placer (native) deposit. The entire stratigraphic column of the Sanaga alluvial deposits is considered potentially mineralised.
Nkoteng is located within the Yaoundé Domain of the Pan African Belt, a large nappe unit that has been thrusted southward onto the Congo Craton and is characterised by low-grade to high-grade garnet bearing metamorphosed schists, gneiss and orthogneisses.
Implications for Future Exploration
The recovery of heavy minerals in the sampled areas has yielded positive results, which is highly encouraging. The mineralisation seems to be continuing positively over a distance of 8 km. BWA is satisfied with the grade and extent of all the target minerals and is planning to conduct follow-up work in the near future across the licence holding.
Competent Person’s Statement
The information in this report which relates to exploration results for the Nkoteng Project is based upon and fairly represents information collected and compiled by Mr Emmanuel Simo, MSc., Senior Geologist and Chief Geologist for BWA, who is a Member of the Australian Institute of Geoscientists.
The results were reviewed by Mr J.N. Hogg, MSc. MAIG, Principal Geologist for Addison Mining Services (AMS) and Non-executive Director of BWAR.
Mr Simo and Mr Hogg have sufficient experience relevant to the style of mineralisation, the type of deposit under consideration and to the activity undertaken to qualify as a Competent Person as defined in the JORC Code 2012 edition of the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves.
Mr Hogg has reviewed and verified the technical information that forms the basis of and has been used in the preparation of this announcement, including all sampling and analytical data, and analytical techniques. Mr Hogg consents to the inclusion in this announcement of the matters based on the information, in the form and context in which it appears.
Forward Looking Statement
This announcement contains forward-looking statements which involve a number of risks and uncertainties. These forward-looking statements are expressed in good faith and believed to have a reasonable basis. These statements reflect current expectations, intentions or strategies regarding the future and assumptions based on currently available information. Should one or more of the risks or uncertainties materialise, or should underlying assumptions prove incorrect, actual results may vary from the expectations, intentions and strategies described in this announcement. No obligation is assumed to update forward looking statements if these beliefs, opinions and estimates should change or to reflect other future developments.
For further information on the Company, please visit http://www.bwagroupplc.com/index.html or contact:
BWA Group PLC James Butterfield Interim Chairman
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+44 (0) 7770 225 253 |
Allenby Capital Limited Corporate Adviser Nick Harriss/Lauren Wright |
+44 (0)20 3328 5656
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Glossary of Technical Terms:
“%” |
percent; |
Al2O3 |
Aluminium Oxide; |
“ALS” |
Australian Laboratory Services; |
“AMS” |
Addison Mining Services; |
"BRGM" |
Bureau de Recherches Géologiques et Minié (French Geological Survey); |
"BWA" |
BWA Group PLC; |
"DTM" |
Digital Terrain Model. Computerised topographic model; |
"DUP" |
Décret d'Utilité Publique (Public Utility Decree); |
"HMS" |
Heavy Mineral Sands; |
“km” |
Kilometre; |
"TiO2" |
Titanium dioxide, also known as titanium (IV) oxide. Generally sourced from ilmenite, rutile, and anatase; |
"Zr" |
Zircon or Zirconium; |
“JORC (2012)” |
the 2012 edition of the JORC code; |
“JORC” |
the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves, as published by the Joint Ore Reserves Committee of The Australasian Institute of Mining and Metallurgy, Australian Institute of Geoscientists and Minerals Council of |
“m” |
metre; |
“ME-XRF11bE” |
Analysis by Fusion/XRF; |
“QA/QC” |
Quality assurance/quality control. |
“µm” |
micrometre or micron, unit of length equalling 1×10−6 metre |
Table 1: Sample details.
Hole ID |
From |
To |
Sample ID |
Lith |
NKA_163 |
0.10 |
1.60 |
26435 |
Plastic Clay |
NKA_078 |
0.00 |
1.90 |
26285 |
Plastic Clay |
NKA_124 |
0.10 |
1.90 |
26367 |
Plastic Clay |
NKA_148 |
0.10 |
2.30 |
26409 |
Plastic Clay |
NKA_119 |
0.65 |
1.35 |
26359 |
Plastic Clay + Saprolite |
NKA_163 |
1.60 |
2.60 |
26436 |
Sand |
NKA_078 |
1.90 |
4.00 |
26286 |
Sand |
NKA_124 |
1.90 |
3.55 |
26368 |
Sand |
NKA_148 |
2.30 |
3.30 |
26410 |
Sand |
NKA_119 |
0.00 |
0.65 |
26358 |
Sand (Secondary alluvial deposits) |
NKA_146 |
0.20 |
1.00 |
26407 |
Sand (Secondary alluvial deposits) |
NKA_166 |
0.00 |
1.20 |
26440 |
Sand (Weathering Sand) |
NKA_140 |
0.05 |
0.90 |
26394 |
Weathering Clay |
NKA_121 |
0.10 |
0.70 |
26362 |
Weathering Clay |
NKA_085 |
0.00 |
0.90 |
26297 |
Weathering Clay |
NKA_159 |
0.10 |
1.80 |
26428 |
Weathering Clay |
NKA_166 |
1.20 |
2.00 |
26442 |
Weathering Clay + Sand + Gravel + Saprolite |
NKA_140 |
0.90 |
1.40 |
26395 |
Weathering Clay + Saprolite |
NKA_121 |
0.70 |
1.20 |
26364 |
Weathering Clay +Ferruginous concretion |
NKA_085 |
0.90 |
1.40 |
26298 |
Weathering Clay +Ferruginous concretion +Saprolite |
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Composite 1 – Plastic clay |
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Composite 2 - Sand |
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Composite 3 – Weathering clay |
The table below presents the results of the testwork. Additional work is required to understand the implications for continuing exploration, as well comparing this mineral separation work to the granulometric work.
Table 2: Results of PSD and analytical results of the THM%.
Composite |
Size Fraction |
PSD (passing %) |
THM% |
dComposite 1 – Plastic clay |
> 0.5 mm |
97.3 |
No heavy minerals |
0.25 – 0.5 mm |
92.8 |
0.04 m% |
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0.063 – 0025 mm |
74.4 |
0.31 m% |
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< 0.063 mm |
49.4 |
0.41 m% |
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Total |
100 |
0.76 m% |
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Composite 2 - Sand |
> 1 mm |
92.4 |
No heavy minerals |
0.5 – 1 mm |
81.4 |
0.08 m% |
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0.25 – 0.5 mm |
68.9 |
0.20 m% |
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0.063 – 0025 mm |
41.4 |
0.54 m% |
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< 0.063 mm |
20.7 |
1.35 m% |
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Total |
100 |
2.17 m% |
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Composite 3 – Weathering clay |
> 1 mm |
88.9 |
No heavy minerals |
0.25 – 1 mm |
68.2 |
0.36 m% |
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0.063 – 0025 mm |
51.5 |
0.28 m% |
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< 0.063 mm |
33.0 |
0.25 m% |
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Total |
100 |
0.89 m% |
APPENDIX: Table 1 (JORC 2012)
Section 1 Sampling Techniques and Data
(Criteria in this section apply to all succeeding sections.)
Criteria |
JORC Code explanation |
AMS Commentary |
Sampling techniques |
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Drilling techniques
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Drill sample recovery
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Logging
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Sub-sampling techniques and sample preparation
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Quality of assay data and laboratory tests
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Verification of sampling and assaying
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Location of data points
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Data spacing and distribution
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Orientation of data in relation to geological structure
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Sample security
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Audits or reviews
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Section 2 Reporting of Exploration Results
(Criteria listed in the preceding section also apply to this section.)
Criteria |
JORC Code explanation |
AMS Comments |
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Mineral tenement and land tenure status
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Exploration done by other parties
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Geology
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Drill hole Information
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Data aggregation methods
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Relationship between mineralisation widths and intercept lengths
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Diagrams
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Balanced reporting
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Other substantive exploration data
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Further work
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[LH1]Emanuel to confirm
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