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23 January 2023
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) as in force in the United Kingdom pursuant to the European Union (Withdrawal) Act 2018. Upon the publication of this announcement via Regulatory Information Service (RIS), this inside information is now considered to be in the public domain.
Andrada Mining Limited
("Andrada" or the "Company")
Uis Mine Mineral Resource Expansion
Additional Inferred Mineral Resource Estimate ("MRE") for Tin
Andrada Mining Limited (AIM: ATM), an African technology metals mining company with a portfolio of mining and exploration assets in Namibia, announces an inferred, JORC (2012), MRE for tin over 11 historically mined pegmatite bodies located close to the actively mined V1/V2 pegmatite at the Uis Mine. These 11 pegmatites have been collectively termed the Proximal Pegmatites and are located within a 3 km radius from the existing processing plant.
Highlights:
§ The V1/V2 pegmatite, as well as the Proximal Pegmatites are located within the mining licence ML134 as part of a swarm comprising more than 180 mineralised pegmatites;
§ The maiden MRE announced on 16 September 2019, of 71.54 Mt of ore over the V1/V2 pegmatite, was based on information derived from 141 historical and 26 confirmatory drill holes;
§ An additional inferred MRE for tin over the Proximal Pegmatites, derived from a further 809 historical drill holes, comprises 57.18 Mt of ore with an average grade of 0.131% tin, and containing 74,857 tonnes of tin metal has now been completed;
§ The historical drill hole information further indicates that the Proximal Pegmatites remain open-ended at depth; and
§ Andrada is embarking on a confirmatory drilling programme to improve the tin resource classification and to evaluate lithium and tantalum potential of the Proximal Pegmatites.
Anthony Viljoen (CEO) commented: "The declaration of this inferred resource, using the historical drill data from the Uis Mine, significantly advances the total Andrada mineral inventory towards management's internal mineral resource target of at least 200 Mt of mineralisation. These additional pegmatites, together with the mineral resource at the V1/V2 orebody, provide an entire resource portfolio of approximately 128 Mt of ore with a gross combined content of 170 kt of tin, making Andrada the owner of one of the largest tin assets globally. Furthermore, through our demonstrated ability to rapidly and profitably scale up production at the existing operations at the Uis mine, we believe Andrada has the ability to compound the Company's economies of scale and position the company as one of the lowest cost tech-metal producers in the next five years.
The existing mineral reserve, that is currently being mined, as well as the ongoing infill drilling programme over the entire mining licence have also shown the potential of lithium mineralisation contained within the same pegmatites. Andrada looks forward to completing the work required to bring the lithium into production, as well as expanding the infill drilling programme to explore the huge opportunity that the Lithium presents as a co-product revenue stream with the tin operation in the coming months. Further announcements on this will be made in due course."
Locality
The mining licence ML134 hosts the Uis Mine. The Uis town is located approximately 200 km northeast of the port of Walvis Bay in Namibia (Figure 1).
Figure 1: Andrada's Uis Mine and mineral licence locality map showing the position of ML134.
Background
The mining licence of the Uis Mine (ML134) comprises a swarm of more than 180 pegmatites. The historical Uis Mine focused on 12 of these pegmatites which were mined by open cast methods before operations were halted in 1990. During that time a comprehensive exploration drilling programme was undertaken, resulting in an extensive database with tin analyses. The 12 pegmatites are grouped into three clusters, namely K, P, and V, as illustrated in Figure 2.
Figure 2: Map of the Proximal Pegmatites depicting modelled clusters.
MRE - V1/V2 Pegmatite
On 16 September 2019 the Company announced a maiden MRE comprising 71.54 Mt of ore over one of the 12 pegmatites, namely the combined V1/V2 pegmatite. The MRE was derived from 141 historical drill holes and 26 confirmatory holes drilled by Andrada during 2019.
MRE - Proximal Pegmatites
The balance of the historically mined pegmatites have been incorporated into this report, based on a further 809 historical drill holes. Minxcon (Pty) Ltd ("Minxcon"), a leading exploration consultancy, was appointed to undertake the compilation of the tin block model over the mineralised Proximal Pegmatites.
Mineralised envelopes were modelled using lithological logs sourced from the surface drillholes and surface mapping of geological contacts.
The wireframes were clipped to the drillhole data and extended along interpreted strike and down-dip extensions. The mineralised envelopes were modelled to define moderate (30°) to steeply (70°) dipping pegmatitic zones which occur within the K, P and V clusters. Individual clusters are characterised by one or two dominant pegmatites, with numerous associated splay pegmatites. Strikes vary from east-west to southwest-northeast, with variable dips within the same cluster.
Geological, and geostatistical domains were delineated based on lithological contacts. Each modelled pegmatite was treated as a separate domain. Selected one-metre sample composites from within the modelled mineralised envelopes, defined the final dataset used for the geostatistical analysis and block model estimation. The mineral resource estimates are spatially coincident, with mineralisation confined to the pegmatite contacts. The pit shell definition was based on an average tin price of USD 30,000/t with ore losses and mining dilution set at 2%. The assumed pit slope angles and metallurgical recovery for Sn were 55° and 64% respectively. Mining, treatment, G&A and selling cost parameters were provided by Andrada and approved by Minxcon. The open pit Mineral Resource figures are stated at a cut-off grade of 0.03% Sn.
Table 1: Andrada Mining tin (Sn) Mineral Resource Estimate (JORC 2012) for the Uis Proximal Pegmatites at a cut-off grade of 0.03% Sn.
Classification |
Gross |
Net Attributable (85%*) |
|
||||
Tonnage (Mt) |
Grade (% Sn) |
Contained Metal (t) |
Tonnage (Mt) |
Grade (% Sn) |
Contained Metal (t) |
Operator |
|
Tin (Sn) |
|
|
|
|
|
|
|
Proximal Pegmatites Measured Resource |
- |
- |
- |
- |
- |
- |
|
Proximal Pegmatites Indicated Resource |
- |
- |
- |
- |
- |
- |
|
Proximal Pegmatites Inferred Resource |
57.18 |
0.131 |
74,857 |
48.60 |
0.131 |
63,628 |
Andrada Mining |
Total Proximal Pegmatite Resource |
57.18 |
0.131 |
74,857 |
48.60 |
0.131 |
63,628 |
Andrada Mining |
Source columns 1-4: Minxcon, Source columns 5-8: Andrada Mining
Note: Tabulated data have been rounded off and this may result in minor computational errors.
* Andrada has an attributable ownership of 85% in ML134 with the remaining 15% owned by The Small Miners of Uis (local shareholders)
Figure 3: Plan view of the drillhole collars and drillhole assay data for the Uis Proximal Pegmatites (source: Minxcon).
Table 2: Andrada Mining tin (Sn) Inferred Mineral Resource Estimates (JORC 2012) for the individual Uis Proximal Pegmatites at a cut-off grade of 0.03% Sn.
Pegmatite |
Gross |
Net Attributable (85%*) |
|
||||
Tonnage (Mt) |
Grade (% Sn) |
Contained Metal (t) |
Tonnage (Mt) |
Grade (% Sn) |
Contained Metal (t) |
Operator |
|
K Cluster |
|
|
|
|
|
|
|
K3 |
5.66 |
0.133 |
7,503 |
4.81 |
0.133 |
6,378 |
Andrada Mining |
K3_1 |
1.47 |
0.115 |
1,694 |
1.25 |
0.115 |
140 |
|
K3_2 |
0.24 |
0.113 |
268 |
0.20 |
0.113 |
228 |
|
K3_3 |
0.49 |
0.110 |
535 |
0.42 |
0.110 |
455 |
|
K3_5 |
0.29 |
0.116 |
340 |
0.25 |
0.116 |
289 |
|
K5 |
18.58 |
0.139 |
25,910 |
15.79 |
0.139 |
22,024 |
|
K5_5 |
0.15 |
0.136 |
204 |
0.13 |
0.136 |
173 |
|
K7 |
0.83 |
0.137 |
1,140 |
0.71 |
0.137 |
969 |
|
K10 |
0.23 |
0.116 |
269 |
0.20 |
0.116 |
229 |
|
K10_1 |
0.32 |
0.118 |
382 |
0.27 |
0.118 |
325 |
|
P Cluster |
|
||||||
P4 |
0.14 |
0.110 |
160 |
0.12 |
0.110 |
136 |
Andrada Mining |
P4_2 |
0.32 |
0.129 |
417 |
0.27 |
0.129 |
354 |
|
P5 |
1.83 |
0.127 |
2,319 |
1.56 |
0.127 |
1,971 |
|
P6 |
1.05 |
0.125 |
1,320 |
0.89 |
0.125 |
1,122 |
|
P6_1 |
0.21 |
0.107 |
228 |
0.18 |
0.107 |
194 |
|
V Cluster |
|
||||||
V4 |
0.81 |
0.104 |
845 |
0.69 |
0.104 |
718 |
Andrada Mining |
V4_2 |
0.42 |
0.093 |
385 |
0.36 |
0.093 |
327 |
|
V4_3 |
0.11 |
0.093 |
103 |
0.09 |
0.093 |
88 |
|
V5 |
1.97 |
0.116 |
2,283 |
1.67 |
0.116 |
1,941 |
|
V5_1 |
0.04 |
0.098 |
41 |
0.03 |
0.098 |
35 |
|
V5_2 |
0.00 |
0.089 |
4 |
0 |
0.089 |
3 |
|
V12 |
11.44 |
0.133 |
15,259 |
9.72 |
0.133 |
12,970 |
|
V12_1 |
0.55 |
0.125 |
690 |
0.47 |
0.125 |
587 |
|
V12_2 |
1.41 |
0.098 |
1,386 |
1.20 |
0.098 |
1,178 |
|
V12_3 |
0.21 |
0.126 |
262 |
0.18 |
0.126 |
223 |
|
V12_4 |
0.01 |
0.080 |
9 |
0.01 |
0.080 |
8 |
|
V13 |
3.91 |
0.133 |
5,192 |
3.32 |
0.133 |
4,413 |
|
V13_1 |
0.36 |
0.128 |
457 |
0.31 |
0.128 |
388 |
|
V13_2 |
4.07 |
0.128 |
5,189 |
3.46 |
0.128 |
4,411 |
|
V13_3 |
0.04 |
0.150 |
63 |
0.03 |
0.150 |
54 |
|
Total Proximal Pegmatite Inferred Resource |
57.18 |
0.131% Sn |
74,857 |
48.60 |
0.131% Sn |
63,628 |
Andrada Mining |
Source columns 1-4: Minxcon; Source columns 5-8: Andrada Mining
Note: Tabulated data have been rounded off and this may result in minor computational errors.
* Andrada has an attributable ownership of 85% in ML134 with the remaining 15% owned by The Small Miners of Uis (local shareholders)
Figure 4: Oblique view of the drillhole collars and drillhole assay data for the Uis Proximal Pegmatites (source: Minxcon).
Although the historical data has a lower confidence due to the absence of physical core, it is deemed sufficiently reliable by the Competent Person to allow the declaration of an Inferred Mineral Resource. The historical drillhole database has sufficient data density (with a 25m to 50m grid spacing) to allow for the estimation of a Measured or Indicated Mineral Resource if the requisite QAQC constraints are in place and a confirmatory drilling programme is undertaken. The Company carried out a confirmatory drilling programme in 2018/2019 on the V1/V2 and determined that the historical ISCOR drillhole data correlates well with the recent check sampling. Accordingly, a Measured, Indicated and Inferred Mineral Resource Estimate was declared in 2019 for the V1/V2 pegmatite by CSA Global (see announcement dated 16 September 2019).
[Note: JORC Table 1, Section 1 (Sampling Techniques and Data), Section 2 (Reporting of Exploration Results) and Section 3 (Estimation and Reporting of Mineral Resources), is included in Appendix 1]
Competent Person Statement
The technical data in this announcement has been reviewed by Uwe Engelmann of Minxcon, who provides consulting services to Andrada. Uwe Engelmann has 24 years of industry-related mining and exploration experience and is a Competent Person for the reporting of Mineral Resources. He is a registered Professional Natural Scientist with the South African Council for Natural Scientific Professions (Pr.Sci.Nat. Reg. No. 400058/08) and is a Fellow of the Geological Society of South Africa. He has reviewed the technical disclosures in this release and undertook the Mineral Resource Estimation and classification for tin for the proximal pegmatites. The Competent Person is independent of Andrada Mining Limited and its subsidiaries.
Glossary of Abbreviations
Sn |
Elemental symbol for tin |
JORC |
The Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves |
Mt |
Million tonnes |
ppm |
Parts per million |
T |
Metric tonnes |
SMU |
Small Miners of Uis |
ATM |
Ticker for Andrada Mining Limited |
Glossary of Technical Terms
Cut-off Grade |
The grade above which Mineral Resources have been reported in order to satisfy the requirements for reasonable prospects of eventual economic extraction |
Geological Model |
The interpretation of mineralisation and geology that controls mineralisation. This is usually generated in a three-dimensional computer environment. |
Geostatistics |
A branch of statistics focussing on spatial datasets and relating to the estimation of elemental grades over a spatially modelled orebody |
Indicated Mineral Resource |
The part of a Mineral Resource for which quantity, grade, quality, etc., can be estimated with a level of confidence sufficient to allow the appropriate application of technical and economic parameters, to support mine planning and evaluation of economic viability |
Inferred Mineral Resource |
The part of a Mineral Resource for which quantity and grade or quality can be estimated on the basis of geological evidence and limited sampling and reasonably assumed, but not verified, geological and grade continuity |
Measured Mineral Resource |
The part of a Mineral Resource for which quantity, grade or quality, etc., are well enough established that they can be estimated with confidence sufficient to allow the appropriate application of technical parameters to support production planning and evaluation of economic viability |
Mineral Resources |
Mineral Resources are sub-divided, in order of increasing geological confidence, into Inferred, Indicated and Measured categories. An Inferred Mineral Resource has a lower level of confidence than that applied to an Indicated Mineral Resource. An Indicated Mineral Resource has a higher level of confidence than an Inferred Mineral Resource but has a lower level of confidence than a Measured Mineral Resource |
Modifying Factors |
Considerations used to convert Mineral Resources to Ore Reserves. These include, but are not restricted to, mining, processing, metallurgical, infrastructure, economic, marketing, legal, environmental, social and governmental factors. |
Pegmatite |
An igneous rock typically of granitic composition, that is distinguished from other igneous rocks by the extremely coarse and systematically variable size of its crystals, or by an abundance of crystals with skeletal, graphic, or other strongly directional growth habits, or by a prominent spatial zonation of mineral assemblages, including monomineralic zones |
For further information please visit the Company's website: www.andradamining.com or contact:
Andrada Mining Limited |
+27 (11) 268 6555 |
Anthony Viljoen, CEO Sakhile Ndlovu, Head of Investor Relations |
|
Nominated Adviser |
+44 (0) 207 220 1666 |
WH Ireland Limited Katy Mitchell |
|
Corporate Advisor and Joint Broker |
|
H&P Advisory Limited Andrew Chubb Jay Ashfield Nilesh Patel |
+44 (0) 20 7907 8500 |
Stifel Nicolaus Europe Limited |
+44 (0) 20 7710 7600 |
Ashton Clanfield Callum Stewart Varun Talwar |
|
Tavistock Financial PR (United Kingdom) |
+44 (0) 207 920 3150 |
Emily Moss Catherine Drummond Adam Baynes |
|
____________________________________________________________________________________________________
Appendix 1 - JORC (2012) Table 1
SECTION 1: SAMPLING TECHNIQUES AND DATA |
||
Criteria |
Explanation |
Detail |
Sampling techniques |
Nature and quality of sampling (e.g., cut channels, random chips, or specific specialised industry standard measurement tools appropriate to the minerals under investigation, such as down hole gamma sondes, or handheld XRF instruments, etc.). These examples should not be taken as limiting the broad meaning of sampling. |
Historical drillhole data (inclusive of diamond and percussion (RC)) exists but limited information is available relating to historical sampling techniques and standards utilised by previous operators on the Project Areas. The historical drillhole data has no accompanying assay QAQC, however this fact is considered in allocation of Mineral Resource classification during modelling. According to historical literature the percussion (RC) samples were taken via a cyclone in 1 m increments.
|
Include reference to measures taken to ensure sample representivity and the appropriate calibration of any measurement tools or systems used.
|
No information pertaining to sampling data information was available for Minxcon to review. |
|
Aspects of the determination of mineralisation that are Material to the Public Report. In cases where 'industry standard' work has been done this would be relatively simple (e.g., 'reverse circulation drilling was used to obtain 1 m samples from which 3 kg was pulverised to produce a 30 g charge for fire assay'). In other cases, more explanation may be required, such as where there is coarse gold that has inherent sampling problems. Unusual commodities or mineralisation types (e.g., submarine nodules) may warrant disclosure of detailed information.
|
No information pertaining to sampling information was available for Minxcon to review. However, according to historical ISCOR documentation the percussion (RC) samples were taken via a cyclone in 1 m increments. Information with respect to possible diamond drilling is not available. |
|
Drilling techniques |
Drill type (e.g., core, reverse circulation, open-hole hammer, rotary air blast, auger, Bangka, sonic, etc.) and details (e.g., core diameter, triple or standard tube, depth of diamond tails, face-sampling bit or other type, whether core is oriented and if so, by what method, etc.). |
Very limited information is available relating to historical drilling utilised by previous operators on the Project Areas. A total of 809 drillholes (percussion (RC) and/or diamond drilling carried out by ISCOR) were found to have sufficient information to qualify them for inclusion in the Mineral Resource Estimation, there are no records of any archived split core or percussion nor their photographs. Limited details are recorded in the database for the diamond drillholes, with unknown core diameter.
|
Drill sample recovery |
Method of recording and assessing core and chip sample recoveries and results assessed. |
Data pertaining to both percussion (RC) drilling and diamond drillhole recoveries are not available; as such, Minxcon cannot comment on the drillhole recoveries. A historical ISCOR document does however mention that a 95% recovery is required and if not achieved the drilling contractor would redrill at their cost.
|
Measures taken to maximise sample recovery and ensure representative nature of the samples.
|
No information pertaining to sample recovery information was available for Minxcon to review. |
|
Whether a relationship exists between sample recovery and grade and whether sample bias may have occurred due to preferential loss/gain of fine/coarse material.
|
No information pertaining to sample recovery information was available for Minxcon to review and hence this could not be investigated. |
|
Logging |
Whether core and chip samples have been geologically and geotechnically logged to a level of detail to support appropriate Mineral Resource estimation, mining studies and metallurgical studies. |
Limited information regarding the logging was available to Minxcon and it is uncertain if the core was logged geotechnically or what percentage of the core was logged or sampled. according to the simplified historical geological logs provided to Minxcon in excel format, drillhole logging is quantitative in nature and as summaries of geological codes and assay interval, i.e., pegmatite, and various country rock lithologies. No photographs were supplied to Minxcon at the time of reporting.
|
Whether logging is qualitative or quantitative in nature. Core (or costean, channel, etc.) photography.
|
Limited information suggests drillhole logging is quantitative in nature. |
|
The total length and percentage of the relevant intersections logged. |
Limited information of what percentage of the core was logged or sampled but from the drillhole database, which is available, it suggests that the entire drillhole was logged and only the pegmatites were sampled.
|
|
Sub-sampling techniques and sample preparation |
If core, whether cut or sawn and whether quarter, half or all cores taken.
|
No information in this regard was available for Minxcon to review. |
If non-core, whether riffled, tube sampled, rotary split, etc. and whether sampled wet or dry. |
Limited details are recorded in the database that samples were crushed to <1.5 mm and the successively riffled to produce a "cup" sized volume which was then milled to "a very fine powder". No supplementary information is given, as such, Minxcon is unable to comment on the appropriateness or representivity of the sampling.
|
|
For all sample types, the nature, quality and appropriateness of the sample preparation technique.
|
No information pertaining QAQC data information was available for Minxcon to review. |
|
Quality control procedures adopted for all sub-sampling stages to maximise representivity of samples.
|
No information pertaining QAQC data information was available for Minxcon to review. |
|
Measures taken to ensure that the sampling is representative of the in-situ material collected, including for instance results for field duplicate/second-half sampling.
|
The entire drillhole pegmatite intercept was sampled which would result in a representative sample of the pegmatite down the hole. The drilling density, up to a 25 m grid, is also fairly tight which would also give a good spread across the pegmatite. |
|
Whether sample sizes are appropriate to the grain size of the material being sampled. |
The cassiterite grains in the pegmatite are fairly coarse and distributed fairly evenly throughout the pegmatite and with the 1 m sample increments, it is believed to be appropriate.
|
|
Quality of assay data and laboratory tests |
The nature, quality and appropriateness of the assaying and laboratory procedures used and whether the technique is considered partial or total. |
Historic assay work using XRF (Sn only) was performed. No QAQC data is available pertaining to historical QAQC or laboratory testwork was available for historical samples. QAQC procedures pertaining to the extensive ISCOR dataset are not documented. |
For geophysical tools, spectrometers, handheld XRF instruments, etc., the parameters used in determining the analysis including instrument make and model, reading times, calibrations factors applied and their derivation, etc.
|
No information pertaining to the laboratory or tools used was available for Minxcon to review. |
|
Nature of quality control procedures adopted (e.g., standards, blanks, duplicates, external laboratory checks) and whether acceptable levels of accuracy (i.e., lack of bias) and precision have been established. |
No information pertaining to QAQC information was available for Minxcon to review. It is however assumed that ISCOR, being a large reputable mining company, would have used appropriate measures to ensure acceptable levels of accuracy and precision. Since there was historical mining, it is also assumed that there would have been reconciliations to the production and recovery figures as a measure of QAQC.
|
|
Verification of sampling and assaying |
The verification of significant intersections by either independent or alternative company personnel. |
Due to limited data pertaining to the sampling and assaying procedures, Minxcon assumes that sampling and assaying of all relevant intersections collected by ISCOR may have been conducted according to industry best practice and may be used for Mineral Resource estimation. Minxcon did undertake checks for overlaps and duplicates and capped the anomalous assay values.
|
Discuss any adjustment to assay data. |
No adjustments were made to the data besides the capping of anomalous grade values.
|
|
Documentation of primary data, data entry procedures, data verification, data storage (physical and electronic) protocols. |
No information pertaining to specific procedures was available but the fact that this historical data is still available and in fairly good condition, indicates there must have been good systems in place. |
|
The use of twinned holes. |
A twinning or confirmatory drilling programme has been completed at the V1/V2 pegmatites which had good correlations. This, in the CP's opinion, goes a long way in confirming the reliability of the historical database as a whole.
|
|
Location of data points |
Accuracy and quality of surveys used to locate drillholes (collar and down-hole surveys), trenches, mine workings and other locations used in Mineral Resource estimation. |
The coordinate system used throughout is WGS84 UTM 33S to survey and verify numerous historical collars which have been identified in the field by Andrada. These positions are consistent with positions recorded in the ISCOR dataset providing confidence in the historical data. There is also a DTM which was used for the depletions of the historical open pit mining.
|
Specification of the grid system used. |
The coordinate system used throughout is WGS84 UTM 33S. |
|
Quality and adequacy of topographic control.
|
There is a DTM for the project area. |
|
Data spacing and distribution |
Data spacing for reporting of Exploration Results. |
Historically, Mineral Resource delineation has been completed using both diamond and percussion (RC) drilling methods. The limited data is on an irregular grid targeting each pegmatite and the sampling database was composited at 1 m.
It is Minxcon's opinion that data spacing, and distribution is sufficient to establish the degree of geological and grade continuity appropriate for the Mineral Resource estimation and classification.
The drillhole density could lend itself to a measured or indicated Mineral Resource if all the QAQC was in place. However, since there is a lack of QAQC only an inferred Mineral Resource has been declared.
|
Whether the data spacing, and distribution is sufficient to establish the degree of geological and grade continuity appropriate for the Mineral Resource and Ore Reserve estimation procedure(s) and classifications applied.
|
The drillhole spacing ranges from about 25 m to 50 m in places and up to 100 m to 200 m elsewhere. This is sufficient to prove geological and grade continuity.
|
|
Whether sample compositing has been applied. |
The samples were collected in 1 m increments and the histograms of the sample width showed that the 1 m samples where the majority and hence the sample data was composited at 1m.
|
|
Orientation of data in relation to geological structure |
Whether the orientation of sampling achieves unbiased sampling of possible structures and the extent to which this is known, considering the deposit type. |
Minxcon is not aware of any core orientation being done on drill cores during the various historic drilling campaigns. However, in most cases drillholes were drilled vertically or at an inclination of about 60 degrees to intersect the shallow to steeply dipping pegmatites as close to right angles as possible.
|
If the relationship between the drilling orientation and the orientation of key mineralised structures is considered to have introduced a sampling bias, this should be assessed and reported if material.
|
The drillholes intersect the pegmatites close to normal and hence no bias is introduced.
|
|
Sample security |
The measures taken to ensure sample security. |
Information on the security of historical samples was not available. |
Audits or reviews |
The results of any audits or reviews of sampling techniques and data. |
Minxcon is not aware of any audits undertaken. |
SECTION 2: REPORTING OF EXPLORATION RESULTS |
||
Criteria |
Explanation |
Detail |
Mineral tenement and land tenure status |
Type, reference name/number, location and ownership including agreements or material issues with third parties such as joint ventures, partnerships, overriding royalties, native title interests, historical sites, wilderness or national park and environmental settings. |
The Project Area is held under valid mining licence ML134 by Uis Tin Mining Company (Pty) Ltd. ML134 is valid for base and rare metals, industrial minerals, semi-precious stones, covers an area of 19,704.02 ha, and expires on 21 August 2028. The V1/V2 pegmatites (not part of this Mineral Resource) are currently being mined. The mining operations are fully licenced, including abstraction of water from boreholes and an Environmental Clearance Certificate. Further exploration activities at the Project are covered by the amended Environmental Clearance Certificate.
|
The security of the tenure held at the time of reporting along with any known impediments to obtaining a licence to operate in the area.
|
The Competent Person is satisfied with the security of tenure. The Competent Person has not identified any threat to the mining lease with continued annual payments and conformance to government notices and directives. |
|
Exploration done by other parties |
Acknowledgment and appraisal of exploration by other parties. |
Acknowledgement is hereby made for the historical exploration conducted between the early 1960s and 1989 by ISCOR. SRK documented the reserve and mine plan report containing the historical estimate of the mineralised tin pegmatites Andrada obtained and digitised a significant portion of the exploration data.
|
Geology |
Deposit type, geological setting and style of mineralisation. |
The tin bearing pegmatites are hosted within the Damara Orogen, a typical pan African-aged (750-440 Ma) orogenic belt. The LCT-type pegmatites forms part of the Uis Pegmatite Swarm, lying to the east and south of the town of Uis and is well-mineralised in comparison to other pegmatites in this swarm. The Uis Pegmatite Swarm has three clusters: Northern, Central and Southern. The pegmatites generally have a northeast to east strike, and dip between 30° and 70° towards the northwest. The southeast dipping host biotite schist and gneiss of the isoclinally folded Amis River Formation (including the Knottenschiefer) of the Damara Supergroup is crosscut by these pegmatites. The mineralisation type is primarily magmatic but may be due to alteration. Primary cassiterite is formed towards the end of a pegmatite's crystallisation history, when enough magmatic differentiation has made tin insoluble.
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Drillhole Information |
A summary of all information material to the understanding of the exploration results including a tabulation of the following information for all Material drillholes: * easting and northing of the drillhole collar * elevation or RL (Reduced Level - elevation above sea level in metres) of the drillhole collar * dip and azimuth of the hole * down hole length and interception depth * hole length.
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It is noted that all the Uis Tin Mine Projects included in the portfolio represent historical database with limited data. Minxcon verified each of the drillhole databases as much as possible during the drillhole desurvey process. A total of 809 drillhole collars are present in the drillhole database were utilised for the Mineral Resource Estimation of which 27 are diamond drillholes and 782 are percussion. Minxcon utilised this information to delineate the mineralisation of the pegmatites and estimation.
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If the exclusion of this information is justified on the basis that the information is not Material and this exclusion does not detract from the understanding of the report, the Competent Person should clearly explain why this is the case.
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A total of 809 drillhole collars are present in the drillhole database applicable to the proximal pegmatites, with additional holes covering V1V2 (not included in this MRE). All the proximal pegmatite drillholes have been used unless there was an absent or null (zero) value. These drillholes were used in the geological modelling but not in the estimation.
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Data aggregation methods |
In reporting Exploration Results, weighting averaging techniques, maximum and/or minimum grade truncations (e.g., cutting of high grades) and cut-off grades are usually Material and should be stated. |
All drillholes were investigated statistically and geostatistically. This analysis resulted in the drillholes being utilised in the Mineral Resource estimation conducted over the Uis Tin Mine. The samples were capped to remove outliers in the database to reduce the bias of very high values. This capping was applied by Minxcon in the Mineral Resource estimation. Minxcon reviewed the database and selected 1 m composite as the optimum sample length to be utilised in the Mineral Resource estimation.
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Where aggregate intercepts incorporate short lengths of high-grade results and longer lengths of low grade results, the procedure used for such aggregation should be stated and some typical examples of such aggregations should be shown in detail.
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The samples were capped to remove outliers in the database to reduce the bias of very high values and composited at 1 m. |
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The assumptions used for any reporting of metal equivalent values should be clearly stated.
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There was no metal equivalent. Only Sn was reported. |
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Relationship between mineralisation widths and intercept lengths |
If the geometry of the mineralisation with respect to the drillhole angle is known, its nature should be reported. If it is not known and only the down hole lengths are reported, there should be a clear statement to this effect (e.g., 'down hole length, true width not known').
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Available information indicates that drilling was conducted to intersect the mineralised pegmatites very close to normal relative to the reef plane. The 3D modelling also takes care of the pegmatite width. |
Diagrams |
Appropriate maps and sections (with scales) and tabulations of intercepts should be included for any significant discovery being reported These should include, but not be limited to a plan view of drillhole collar locations and appropriate sectional views.
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All relevant diagrams pertaining to sampling type and its distribution, as well as geological and block models are presented in their respective sections and have been generated in accordance with the guidelines described in the JORC Code. |
Balanced reporting |
Where comprehensive reporting of all Exploration Results is not practicable, representative reporting of both low and high grades and/or widths should be practiced to avoid misleading reporting of Exploration Results.
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The Mineral Resource estimate considered the total dataset, for the generation of the geological model and estimated block model. CAE (Datamine) Studio RM™ software was used to conduct statistical and geostatistical analyses, conduct spatial continuity analysis and generate the estimated block models.
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Other substantive exploration data |
Other exploration data, if meaningful and material, should be reported including (but not limited to): geological observations; geophysical survey results; geochemical survey results; bulk samples - size and method of treatment; metallurgical test results; bulk density, groundwater, geotechnical and rock characteristics; potential deleterious or contaminating substances.
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Various exploration campaigns have been conducted at the Project sites over the years, but this information is not available or relevant to the current Mineral Resource update. No other exploration data other than that presented for the purposes of the Mineral Resource estimation is therefore included in this Report.
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Further work |
The nature and scale of planned further work (e.g., tests for lateral extensions or depth extensions or large-scale step-out drilling). |
The drillhole database integrity has resulted in the Mineral Resource estimation being classified only as Inferred Mineral Resource. Minxcon recommends that a programme of confirmatory drilling be undertaken to collect sufficient data to complete an in-depth investigation into the reliability of the historical sampling, to assist in Mineral Resource classification upgrade. Minxcon recommends that further drilling be aimed at confirming the lateral extent and mineralisation of the W Cluster Pegmatites.
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Diagrams clearly highlighting the areas of possible extensions, including the main geological interpretations and future drilling areas, provided this information is not commercially sensitive.
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The proximal pegmatites have been mapped on surface (figure in report) and the lateral and depth extensions of these can be investigated with further drilling. |
SECTION 3: ESTIMATION AND REPORTING OF MINERAL RESOURCES |
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Criteria |
Explanation |
Detail |
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Database integrity |
Measures taken to ensure that data has not been corrupted by, for example, transcription or keying errors, between its initial collection and its use for Mineral Resource estimation purposes. |
Minxcon verified the drillhole database during the drillhole desurvey process as far as possible. The Uis Proximal Pegmatites drillhole database was checked for duplicates, overlapping and missing intervals, whilst all fields were checked for spurious or out of range values. The overlaps and duplicates were removed to create a final database file consisted of drillhole data. Minxcon was not involved in the initial data capture process. |
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Data validation procedures used. |
The data that could be validated by Minxcon was the surface outcrop mapping and historical collar positions in the field. The CP does however place huge importance on the fact that the V1/V2 pegmatite data (geological and grade) was confirmed by a confirmatory drilling programme. This goes a long way in validating the reliability of the historical drillhole database. |
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Site visits |
Comment on any site visits undertaken by the Competent Person and the outcome of those visits. |
A site visit was undertaken on 17 November 2022 to verify the pegmatite surface outcrop and historical drillhole collars. This was achieved and the surface outcrop and historical collars were confirmed. The historical drillhole diameter was noted to be variable in size and hence an indication that both RC and diamond drillholes were drilled. |
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If no site visits have been undertaken indicate why this is the case.
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Not applicable - see above. |
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Geological interpretation |
Confidence in (or conversely, the uncertainty of) the geological interpretation of the mineral deposit. |
Geological modelling comprises two elements namely modelled mineralised envelopes and a DTM of the topography, which includes the depletions from historic open pit mining. Mineralised envelopes were modelled using the lithological logs sourced from the surface drillholes and surface exposure / mapping. The wireframes are clipped to the drillhole data and have been extended along strike and down-dip by reasonable interpretation.
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Nature of the data used and of any assumptions made. |
The geological modelling was completed using Leapfrog software. A total of 32 mineralised pegmatite envelopes have been modelled from the 809 drillholes. The pegmatites are very distinct from the surrounding schist.
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The effect, if any, of alternative interpretations on Mineral Resource estimation.
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There has been no alternative geological model. The pegmatite geology is very distinctive. |
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The use of geology in guiding and controlling Mineral Resource estimation. |
In general, the mineralised envelopes have been modelled to define elongated generally moderately (30°) to steeply (70°) dipping pegmatitic zones which occur within distinct clusters (K, P and V). Individual clusters are characterised by one or two dominant pegmatites, with numerous associated splay pegmatites. Strikes vary from east-west to southwest-northeast, with varying strikes and dips occurring within the same cluster. |
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The factors affecting continuity both of grade and geology. |
Several xenoliths (country or waste rock contained within the mineralised pegmatites) have been modelled within the larger pegmatites. The estimation is limited to the distinctive pegmatite wireframes based on the 809 drillholes. |
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Dimensions |
The extent and variability of the Mineral Resource expressed as length (along strike or otherwise), plan width, and depth below surface to the upper and lower limits of the Mineral Resource. |
Orebody widths, strike and depth extents are highly variable and are based on the interpretation of the drillhole and surface exposure data. Mineralised intercepts do not represent actual orebody widths due to the varying inclination of intercepts relative to the mineralised zones. The modelled mineralised widths are generally less than 30 m. The K cluster of mineralisation extends along strike for approximately 1,740 m and 240 m down the dip slope. The P cluster has a strike extent of approximately 860 m and a maximum downdip depth of 185 m. The V cluster has a strike length of approximately 1,900 m and maximum downslope extent of 240 m. No geological structures such as dykes or faults have been modelled. No additional geological losses have been applied to the Mineral Resource estimates. |
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Estimation and modelling techniques |
The nature and appropriateness of the estimation technique(s) applied and key assumptions, including treatment of extreme grade values, domaining, interpolation parameters and maximum distance of extrapolation from data points. If a computer assisted estimation method was chosen include a description of computer software and parameters used. |
The only variable analysed and available for estimation is tin (Sn %). No assumptions with respect to the correlation of Sn % with any other variable have been made. The geological, and geostatistical domains were delineated on the basis of geological structure. For all mineralised envelopes, the mean length of the sample populations was close to 1 m, and given the data, a 1 m compositing interval was selected and applied to the desurveyed drillholes. The raw drillhole analytical data for Sn % indicates very low variance and coefficient of variation, therefore longer composite lengths would not be required. Each modelled pegmatite was treated as a separate domain. Mineralised zones, generally within relative proximity, with similar structural orientations (strike and dip) were also grouped zones. The K pegmatite swarm comprised 10 separate domains, the P swarm comprised 6 domains and the V group comprised 15 individual domains. CAE (Datamine) Studio RM™ was used to conduct statistical and geostatistical analyses, conduct spatial continuity analysis and generate the Ordinary Kriged estimated block models. |
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The availability of check estimates, previous estimates and/or mine production records and whether the Mineral Resource estimate takes appropriate account of such data. |
In 1989 SRK compiled a LoM plan (excluding V1/V2) for ISCOR with proven and probable reserves of 70.32 Mt @ a Sn grade of 0.136 % Sn. This was probably not compliant in today's terms but correlates closely to this CPR's Inferred Mineral Resource. |
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The assumptions made regarding recovery of by-products. |
V1/V2 pegmatites have Li and Ta grade information with the more recent drilling campaigns but the historical proximal pegmatites do not have any data relating to these by-products. This needs to be investigated further with the future drilling.
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Estimation of deleterious elements or other non-grade variables of economic significance (e.g., sulphur for acid mine drainage characterisation). |
No estimation pertaining to deleterious elements or other non-grade variables of economic significance (e.g., sulphur for acid mine drainage characterisation) have been conducted. |
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In the case of block model interpolation, the block size in relation to the average sample spacing and the search employed. |
Block model estimates or grade interpolation for each Uis Proximal Pegmatite mineralised envelope, were completed using parent cell estimates in orthogonal (unrotated) block models The block model parameters are presented in Tables in the report. Estimates were performed individually for each modelled mineralised envelope, using only the composite data extracted from that respective envelope. Additional block model splits were used, to assist with filling the modelled mineralised envelopes to ensure the volume of the mineralised shells was honoured as far as possible. The Mineral Resource estimate was constrained by the modelled mineralised envelopes. Three estimates were performed using three search volumes as per the search parameters described previously. The resultant block models were combined with one another, giving preference to the lowest (smallest) search volume. Multiple estimation techniques were employed in the interpolation to allow for cross-validation of methods and testing for conditional bias. Ordinary kriging (OK) was utilised for Mineral Resource estimation purposes. Secondary estimates were completed using inverse distance to the power 2 (ID2SNC) and 0 (produces an arithmetic mean within the respective search - AVGSNC) and a nearest neighbour (NNSNC) method.
The Block model parameters for the mineralised areas in the Uis Proximal Pegmatite areas and block size are shown in the table.
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Any assumptions behind modelling of selective mining units. |
No assumptions were made in terms of selective mining units with respect to the cell size selected.
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Estimation and modelling techniques (continued) |
Any assumptions about correlation between variables. |
The only variable analysed and available for estimation is tin (Sn %). No assumptions with respect to the correlation of Sn % with any other variable have been made.
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Description of how the geological interpretation was used to control the resource estimates.
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The Mineral Resource estimation has been restricted to the hard boundaries encompassed by the geological wireframes. |
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Discussion of basis for using or not using grade cutting or capping. |
An extreme value or outlier analysis was completed on the composite data selected from sub-clusters of the modelled mineralised envelopes. Composite tin grades greater than the selected capping grade were set to the selected grade to reduce the potential impact extreme values may have on the block model estimation. The analysis comprised examination of cumulative coefficient of variation plot, cumulative log probability plots and quantile analyses to determine the presence of extreme value outliers. Capping values were determined for each of the geological or geostatistical domains. In general, the capping values were within the 99th percentile of the respective distributions.
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The process of validation, the checking process used, the comparison of model data to drillhole data, and use of reconciliation data if available. |
Several data-model reconciliations were performed. Firstly, a visual inspection of drillhole composite values with respect to the estimated block model was completed. Visually there is a reasonable correlation between the estimated ordinary krige tin values and the composite tin values.
Basic statistics have been compiled comparing the model estimates and composites. Regressions between various interpolants and the respective kriged value were tested for the total estimated block model (irrespective of final Mineral Resource categorisation). Correlation coefficients ("R") of greater than 0.90 were achieved, indicating a reliable estimate for the Ordinary kriging relative to the other methods tested. Scatter plots of the various interpolants with respect to one another were also inspected for possible indications of bias in the OK estimate. SWATH plots were also conducted on the estimation.
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Moisture |
Whether the tonnages are estimated on a dry basis or with natural moisture, and the method of determination of the moisture content.
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There was no data available for the moisture content, so the tonnage is assumed to be dry at this stage. |
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Cut-off parameters |
The basis of the adopted cut-off grade(s) or quality parameters applied. |
The cut-off parameters used for the cut-off grade and RPEEE pits are detailed below. The resource has been declared at a cut-off grade of 0.03 % Sn and within the optimised pit.
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Mining factors or assumptions |
Assumptions made regarding possible mining methods, minimum mining dimensions and internal (or, if applicable, external) mining dilution. It is always necessary as part of the process of determining reasonable prospects for eventual economic extraction to consider potential mining methods, but the assumptions made regarding mining methods and parameters when estimating Mineral Resources may not always be rigorous. Where this is the case, this should be reported with an explanation of the basis of the mining assumptions made.
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The mining method assumed is open pit mining as per the historical operations and current operations at the V1/V2 pegmatites. See RPEEE parameters above. |
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Metallurgical factors or assumptions |
The basis for assumptions or predictions regarding metallurgical amenability. It is always necessary as part of the process of determining reasonable prospects for eventual economic extraction to consider potential metallurgical methods, but the assumptions regarding metallurgical treatment processes and parameters made when reporting Mineral Resources may not always be rigorous. Where this is the case, this should be reported with an explanation of the basis of the metallurgical assumptions made.
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A process recovery of 64% has been used for the RPEEE which is based on the DFS work. |
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Environmental factors or assumptions |
Assumptions made regarding possible waste and process residue disposal options. It is always necessary as part of the process of determining reasonable prospects for eventual economic extraction to consider the potential environmental impacts of the mining and processing operation. While at this stage the determination of potential environmental impacts, particularly for a greenfields project, may not always be well advanced, the status of early consideration of these potential environmental impacts should be reported. Where these aspects have not been considered this should be reported with an explanation of the environmental assumptions made.
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Based on the V1/V2 operations no environmental factors or assumptions were deemed material, and thus none were considered. |
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Bulk density |
Whether assumed or determined. If assumed, the basis for the assumptions. If determined, the method used, whether wet or dry, the frequency of the measurements, the nature, size and representativeness of the samples.
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No primary density data or database was available for the proximal pegmatites. Pegmatite material has an assigned density of 2.65 t/m3, whilst the host biotite schist and gneiss has been assigned a density of 2.76 t/m3. This is based on the V1/V2 pegmatite work. |
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The bulk density for bulk material must have been measured by methods that adequately account for void spaces (vugs, porosity, etc.), moisture and differences between rock and alteration zones within the deposit.
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No information relating to a bulk sample was available. There is very little if any weathering on surface, so the density of the pegmatite is the same throughout. |
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Discuss assumptions for bulk density estimates used in the evaluation process of the different materials.
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See above. |
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Classification |
The basis for the classification of the Mineral Resources into varying confidence categories. |
The Mineral Resource estimates were categorised on the basis matrix of criterion dependant on the data type and quantity, quality and standards, quality assurance and quality control protocols, range of the respective modelled spatial continuity, number of composites, minimum and maximum number of samples and the performance (quality) of the kriging estimate. The total estimated block model within the modelled mineralised envelopes for all areas were classified as Inferred Resources, primarily due to uncertainty associated with the source data. For the Uis Proximal Pegmatite Mineral Resource estimate, a portion of the estimated Inferred Mineral Resource includes material that may be regarded as extrapolated beyond the limits of available sampling / analytical data. The Mineral Resource estimate has been completed using 3 search volumes. The 3rd search volume estimate can be considered "extrapolated", as it is estimated using composite data present within two times the modelled search volume for a particular modelled envelope. Extrapolated inferred Mineral Resource is approximately 7.6%.
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Whether appropriate account has been taken of all relevant factors (i.e., relative confidence in tonnage/grade estimations, reliability of input data, confidence in continuity of geology and metal values, quality, quantity and distribution of the data).
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Mineral Resource was classified as Inferred Mineral Resource due to the database confidence level discussed in database integrity section of this report. If QAQC was available, the resource could have been classified as a measured or indicated Mineral Resource based on the data density, but the resource was downgraded. |
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Whether the result appropriately reflects the Competent Person's view of the deposit. |
It is the Competent Person's opinion the Mineral Resource estimation conducted by Minxcon is appropriate and presents a reasonable result in line with accepted industrial practices.
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Audits or reviews |
The results of any audits or reviews of Mineral Resource estimates. |
Internal audits and peer review were completed by Minxcon which verified and considered the technical inputs, methodology, parameters and results of the estimate. No independent review has been completed for the Mineral Resource estimate presented in this Report.
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Discussion of relative accuracy/ confidence |
Where appropriate a statement of the relative accuracy and confidence level in the Mineral Resource estimate using an approach or procedure deemed appropriate by the Competent Person. For example, the application of statistical or geostatistical procedures to quantify the relative accuracy of the resource within stated confidence limits, or, if such an approach is not deemed appropriate, a qualitative discussion of the factors that could affect the relative accuracy and confidence of the estimate. |
The Mineral Resource estimate for the Uis Proximal Pegmatites was completed using geostatistical methods to produce local estimates which provide a measure of the relative accuracy and confidence and quality of the estimate. The estimate has been compared with the composites used to estimate the block model and a high degree of correlation has been established through various reconciliation methods.
The quality of the estimate has been measured using various estimation parameters. Although the Mineral Resource estimate has been classified as Inferred, the estimation contains measures of estimation quality such that the estimate can be subdivided into various levels of quality. The table below depicts the various estimation quality and confidence parameters for the Uis Mineral Resource estimate.
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The statement should specify whether it relates to global or local estimates, and, if local, state the relevant tonnages, which should be relevant to technical and economic evaluation. Documentation should include assumptions made and the procedures used.
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Regional accuracy is considered acceptable as evidenced by the swath plots, and direct sample point versus block model checks have ensured acceptable local accuracy with regards the estimated Projects.
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These statements of relative accuracy and confidence of the estimate should be compared with production data, where available. |
Accuracy of the estimate relative to production data cannot be ascertained at this point as the production figures are not readily available. However, the new resource correlates well with the historical 1989 SRK reserve. |
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About Andrada Mining Limited
Notes to Editors
Andrada Mining Limited, formerly Afritin Mining Limited, is a London-listed technology metals mining company with a vision to create a portfolio of globally significant, conflict-free, production and exploration assets. The Company's flagship asset is the Uis Mine in Namibia, formerly the world's largest hard-rock open cast tin mine.
Lithium laboratory test work completed during the 2022 calendar year indicated a high-grade, ultra-low iron lithium petalite concentrate. The test work to convert lithium petalite concentrate to battery-grade lithium hydroxide was initiated with Nagrom, a leading Australian processing company, and commercial engagements with lithium petalite concentrate off - takers are on-going.
An exploration drilling programme is currently underway with the aim of expanding the tin resource over the fourteen additional, historically mined pegmatites, all of which occur within a 5 km radius of the current processing plant. The Company has set a mineral resource target of 200 Mt to be delineated within the next 5 years. The substantial mineral resource potential allows the Company to consider economies of scale.
Andrada is managed by a board of directors with extensive industry knowledge and management team with deep commercial and technical skills. Furthermore, the Company is committed to the sustainable development of its operations and the growth of its business. This is demonstrated by how the leadership team places significant emphasis on creating value for the wider community, investors, and other key stakeholders. Andrada has established an environmental, social and governance system which has been implemented at all levels of the Company and aligns with international standards.
-END-
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