Last checked at 6 Feb 2023 07:00
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")
Drilling Delivers a Significant Lithium Resource Upgrade at the Uis Mine
Andrada Mining Limited, formerly Afritin Mining Limited, (AIM: ATM) an African technology metals mining company with a portfolio of mining and exploration assets in Namibia, is pleased to announce an updated lithium, tin, rubidium, and tantalum Mineral Resource Estimate (MRE), at its flagship Uis Mine ("Uis"). This updated MRE, is in accordance with JORC (2012) and is a result of the substantial 7,000 metre drilling programme undertaken in 2022 to expand and increase the main V1/V2 pegmatite deposit currently being mined at Uis.
Highlights:
§ Updated MRE for the V1/V2 deposit with lithium and tantalum upgraded to a Measured and Indicated classification as a result of infill drilling.
§ Lithium average grade has increased to 0.73% Li20 from 0.63% Li2O declared in 2019, total contained Li2O tonnes have increased by 30% to 587 000 tonnes.
§ Updated resource gives a Lithium Carbonate Equivalent of 1.45 million tonnes.
§ The Measured and Indicated lithium resources increased by 47% to 38Mt.
§ Tin average grade has increased to 0.15% Sn from a previous average of 0.134% Sn, resulting in contained tin metal content of 120 000 tonnes.
§ Maiden resource declared for rubidium with a contained total of 109 400 tonnes at an average grade of 0.14% Rb.
§ Total MRE for the V1/V2 deposit inclusive of mining depletion has increased to 81 Mt from 72 Mt.
Anthony Viljoen (CEO) commented:
"I am very pleased to announce a new enlarged lithium resource at our Uis Mine in Namibia following significant drilling programme in 2022. This confirms our belief that Uis is a globally significant lithium and tin resource that remains open at depth and is one of over 180 mineralised pegmatites within 5km of the Uis processing facility. The drilling programme has exceeded our expectations, delivering higher grades, and has increased the overall tonnage by 13% when compared to the previous resource estimate from 2019 and 30% more contained lithium. The updated Mineral Resource Estimate is solely from V1/V2 pegmatite, which clearly highlights the significant untapped potential of the wider Uis pegmatite swarm across our licence area.
"This MRE has been delivered ahead of our lithium pilot plant commissioning which is due to come online in Q2 2023 and is an important step to realise the additional lithium and tantalum revenue streams alongside our tin production. This new resource will increase the economics for Andrada and will form the basis for the next phase of expansion and growth for the Uis mine.
"The next phase of exploration will investigate the other proximal pegmatites at Uis with the end goal of repeating this process and ultimately expand the resource at Uis to achieve the exploration target of 200 Mt."
Overview of results
In January 2022, Andrada Mining initiated an exploration drilling programme aimed at upgrading the resource classification for lithium (hosted in petalite) and tantalum over the V1/V2 deposit to align with the existing classification for tin. The 2022 infill drilling reduced the drill hole spacing of the Andrada holes to a nominal 60 m by 60 m in the well-drilled portions of the V1/V2 deposit and up to 80 m by 200 m over areas of known mineralisation around the deeper portions of the deposit. A combined total of 51 infill drill holes (Fig.1), 22 DD and 29 RC, obtained in 2022, 26 holes from 2018/19 and historical drill information from the company and historical operations exist over the deposit. This information was utilised to generate the updated Mineral Resource estimate.
Figure 1: Image indicating the location and name of the drill holes from the 2022 programme. Note: Assay results for some holes holes (V1V2024,34,35,37,38,40,43,44,48,50,51,52,54,58 and 80) were not available at the time of reporting but geological logging from these holes were used to constrain the geological modelling. Assay results from all other holes have been reported.
The updated MRE for V1/V2 is reported in accordance with the JORC Code (2012) and contains 81 Mt of mineralised pegmatite at an average grade of 0.73 % Li2O and 0.15 % Sn. This includes a total of 21 Mt at 0.72 % Li2O in the Measured category, 17 Mt at 0.73 % Li2O in the Indicated category and 43 Mt at 0.73 % Li2O in the Inferred category. The MRE is reported within a conceptual pit shell to demonstrate reasonable prospects for eventual economic extraction (RPEEE), and is reported on a gross basis in Error! Reference source not found. and an attributed basis in Error! Reference source not found..
Table 1: V1 and V2 deposit MRE in accordance with JORC (2012) on a gross basis
Resource | Gross Basis (100% of V1/V2 deposit) | |||||||||
Classification | Tonnes (Mt) | Sn % | Contained Sn metal (t) | Li2O % | Contained Li2O (t) | LCE* (t) | Ta ppm | Contained Ta metal (t) | Rb % | Contained Rb metal (t) |
Measured | 21 | 0.14 | 29 000 | 0.72 | 147 000 | 363 531 | 99 | 2 040 | 0.15 | 31 500 |
Indicated | 17 | 0.15 | 25 000 | 0.73 | 125 000 | 309 125 | 88 | 1 520 | 0.14 | 23 800 |
Inferred | 43 | 0.15 | 66 000 | 0.73 | 315 000 | 778 995 | 78 | 3 400 | 0.13 | 55 900 |
Total | 81 | 0.15 | 120 000 | 0.73 | 587 000 | 1 451 651 | 86 | 6 960 | 0.14 | 111 200 |
Source: CSA Global
Note: The constraining pit shell is based on a tin price of US$25,500/t and a price of US$1,500/t for a 4 % Li2O petalite concentrate. Losses and mining dilution were set at 5%. Pit slope angles were assumed to be 55° with an assumed metallurgical recovery of Sn of 80% producing a concentrate of 60 % Sn, and Li2O (as petalite) recovery of 45 %. Mining, Treatment, G&A and Selling Costs have been supplied by Andrada and reviewed for reasonableness by CSA Global. Tabulated data have been rounded off and this may result in minor computational errors. Contained metal for lithium refers to lithium oxide (Li2O). *- LCE - Lithium carbonate equivalent
Table 2: V1 and V2 deposit MRE reported on an Attributable Basis in accordance with JORC (2012)
Resource | Attributed basis (85%) | |||||||||
Classification | Tonnes (Mt) | Sn % | Contained Sn metal (t) | Li2O % | Contained Li2O metal (t) | LCE* (t) | Ta ppm | Contained Ta metal (t) | Rb % | Contained Rb metal (t) |
Measured | 18 | 0.14 | 24 650 | 0.72 | 124 950 | 309 001 | 99 | 1 734 | 0.15 | 26 775 |
Indicated | 14 | 0.15 | 21 250 | 0.73 | 106 250 | 262 756 | 88 | 1 292 | 0.14 | 20 230 |
Inferred | 73 | 0.15 | 56 100 | 0.73 | 267 750 | 662 146 | 78 | 2 890 | 0.13 | 47 515 |
Total | 69 | 0.15 | 102 000 | 0.73 | 498 950 | 1 233 903 | 86 | 5 916 | 0.14 | 94 520 |
Source: CSA Global
Note: Tabulated data have been rounded off and this may result in minor computational errors. Contained metal for lithium refers to lithium oxide (Li2O)
* Andrada has an attributable ownership of 85% in Uis with the remaining 15% owned by The Small Miners of Uis (SMU)
Table 3: Percentage change of tonnes contained, grades and deposit size.
MRE Year | Tonnes (Mt) | Sn % | Contained Sn metal (t) | Li2O % | Contained Li2O (t) | Ta ppm | Contained Ta metal (t) |
2019 | 72 | 0.134 | 95 539 | 0.63 | 450 265 | 85 | 6 091 |
2023 | 81 | 0.15 | 120 000 | 0.73 | 587 000 | 86 | 6 960 |
% Change | 13% | 12% | 26% | 16% | 30% | 1% | 14% |
The infill drilling programme undertaken in 2022 has resulted in an increased mineral resource classification for lithium and tantalum and an increase of the overall tonnage when compared to the maiden MRE published in 2019. In addition, an estimate has been provided on rubidium for the first time, highlighting the polymetallic nature of the deposit. Rubidium is found within mica which is currently being concentrated as a potential by-product.
Geology and geological interpretation
The V1/V2 deposit is hosted within the Damara Orogen, a typical pan African-aged (750-440 Ma) orogenic belt which formed during the assembly of Gondwana. The orogenesis produced voluminous quantities of granitic magmatism during the syn-tectonic phases of collision. This was followed by a pegmatitic phase of magmatism in the post-tectonic environment, populating the Damara Orogen with numerous pegmatitic intrusions.
The V1/V2 pegmatite has a sigmoidal shape in plan and is hosted in biotite schists and the distinctive cordierite (and biotite and quartz replacements of cordierite)-bearing knotted schist (the so-called "knottenschiefer"). The pegmatite strikes to the northeast and dips to the northwest at between 30° and 50°. The tin and lithium mineralisation style is primarily magmatic although some of the tin mineralisation may be associated with a late stage mica rich greisen phase. The primary lithium mineral is petalite.
Modelling and estimation
An in-situ MRE was undertaken for the pegmatite bodies, the data was loaded and utilized to construct a geological model followed by geostatistical analyses.
An estimation was carried out for Sn, Li, Nb, Rb and Ta by ordinary kriging into a block model of 20 m x 20 m x 10 m (X x Y x Z), the block size being selected after a sensitivity analysis was undertaken on a range of block sizes with an emphasis on the grade/tonnage sensitivity around the expected cut-off grade, top cutting was applied to Sn (1.0% Sn) within both the V1 and V2 pegmatite wireframes with the result making minimal difference to the average-declustered grade.
A five individual element estimation was undertaken in three passes, with each subsequent pass extending the search ellipse and decreasing the minimum number of samples to be used for estimation. The first pass search ellipse had the same dimensions as the variogram ranges. Subsequent estimation passes were extended, and the minimum number of samples used was reduced until in the third pass minimum was set to 4 samples.
Estimates were validated by comparing graphical sections showing block grades (Fig.2, Fig.3 and Fig.4) vs composite grades, domain averages with de-clustered means and by trend (swath) plots.
The previous MRE was carried out by CSA Global in September 2019 when only Sn was classified as Measured, Indicated, and Inferred, and all Ta and Li2O Mineral Resources were classified as Inferred. Estimated grades for Sn, Ta and Li2O are similar between the two models, but tonnages have increased due to infill and extensional drilling.
Figure 2: Typical cross section of the Block model and Input Composite data coloured by Sn Grade, looking northeast.
Figure 3: Typical cross section of the Block model and Input Composite data coloured by Li Grade
Figure 4: Typical cross section of the Block model and Input Composite data coloured by Ta Grade
Mineral resource classification criteria
The Mineral Resource has been classified as Measured, Indicated and Inferred Mineral Resource (Figure 5) based on data quality, sample spacing, geological interpretation and from ordinary Kriging (OK), specifically, the slope of regression (SoR) and the kriging efficiency (KE) metrics. For Measured Mineral Resources an average SoR > 0.7 was required, Indicated Mineral Resources an average SoR > 0.5 was required and all other Mineral Resources not already classified and constrained to blocks not more than 50 m from the nearest sample and with at least 4 samples within the search neighbourhood, were classified as Inferred Mineral Resources. The 50 m constraint ensures that extrapolation is limited to 50 m.
The preliminary classification groupings were reviewed in 3D and plan view, identifying coherent zones of each class. Subsequent polygons were defined for Measured, Indicated and Inferred Mineral Resources within which the final classification categories were assigned. All blocks estimated and classified as contained within the RPEEE pit shell.
Figure 5. Plan View of the MRE Block Model, Coloured by CLASS (Red = Measured, Green = Indicated, Blue = Inferred), with drillhole collars displayed coloured by drill phase. Triangle collar points highlight only Geology logging was available.
Competent Person statement
The technical data relating to the Mineral Resources in this announcement has been reviewed by Anthony Wesson of CSA Global, who provides geostatistical consulting services to Andrada. Anthony Wesson has 45 years of industry related mineral project development experience and is a Competent Person for the reporting of Mineral Resources. He has been a Fellow of the AusIMM for more than 25 years. He has reviewed the technical disclosures in this release and has undertaken the Mineral Resource Estimation and classification for tin, lithium, tantalum, and rubidium. Mr Wesson consents to the inclusion of the information in the form and context in which it appears.
The technical data relating to the exploration results in this announcement has been reviewed by Michael Cronwright (M.Sc., FGSSA, Pr. Sci Nat. (Geological Sciences)) of CSA Global, who provides geological consulting services to Andrada. Mr Cronwright is the Principal Consultant - Battery Metals for CSA Global and has 23 years' experience in mineral exploration and is a Qualified Person under the AIM and ASX Rules. Mr Cronwright consents to the inclusion of the information in the form and context in which it appears.
Glossary of abbreviations
DD | Diamond core drilling |
LCE | Lithium Carbonate Equivalent |
Li | Symbol for Lithium |
Li → Li2O | Metal to metal-oxide conversion factor of 2.153 |
Li → LCE | Metal to lithium carbonate conversion factor of 5.323 |
Li2O | Lithium oxide |
JORC | The Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves |
KE | Kriging Efficiency |
MRE | Mineral Resource Estimate |
PPM | Parts Per Million |
QA/QC | Quality Assurance / Quality Control |
Rb | Symbol for Rubidium |
RC | Reverse Circulation drilling |
RPEEE | Reasonable Prospects for Eventual Economic Extraction |
Sn | Symbol for Tin |
SoR | Slope of Regression |
Ta | Symbol for Tantalum |
V1/V2 | Name of the targeted pegmatite unit, V1/V2 denotes where the V1 and V2 pegmatites have merged at depth. |
Glossary of technical terminology
Apparent thickness | The relationship between apparent width and true thickness is based on the formula by Addie (1968 Economic Geology, vol 63, pp 188-189). |
Dip angle | The angle of inclination measured downward from horizontal. |
Geological model | The interpretation of mineralisation and geology that controls mineralisation. This is usually generated in a three-dimensional computer environment. |
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 |
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 |
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 Classification | Mineral Resources are sub-divided, in order of increasing confidence in geological evidence and sampling (grade) knowledge, into Inferred, Indicated and Measured classes. 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. |
Pegmatite | An igneous rock typically of granitic composition, which 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. |
Petalite | Lithium bearing aluminosilicate (LiAlSi4O10) with a maximum theoretical Li content of 4.5%. Current applications largely in the glass and ceramic industry but can potentially be used in the battery chemical market using similar processes and technologies used to process spodumene. |
Xenolith | A foreign rock fragment (e.g., schist) within an intrusive body (e.g., pegmatite) that is unrelated to the igneous body. |
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
| +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 |
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About Andrada Mining Limited
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 a 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.
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