REG - Zinnwald Lithium PLC - Further update to Mineral Resource Estimate
06/06/2024 07:00
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RNS Number : 3071R Zinnwald Lithium PLC 06 June 2024
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Zinnwald Lithium plc / EPIC: ZNWD.L / Market: AIM / Sector: Mining
6 June 2024
Zinnwald Lithium plc ("Zinnwald Lithium" or the "Company")
Further update to Mineral Resource Estimate
221% increase in Measured Resources to support materially increased production
Zinnwald Lithium Plc (AIM:ZNWD) is pleased to announce the publication of a
further update to its independent Mineral Resource Estimate ("MRE") for its
100% owned Zinnwald lithium project ("Zinnwald" or the " Project") located in
Saxony, eastern Germany.
A previous update to the Project's MRE, published on 21 February 2024,
indicated that it was the second largest hard-rock resource in the European
Union ("EU"). Following this, a geometallurgical testwork programme was
undertaken to provide a higher level of confidence in the Mineral Resource
within the mineralised albite granite, which surrounds the lenses of higher
grade greisen mineralisation.
June 2024 MRE Highlights:
· Additional 25.0Mt @ 2,090ppm Li (52kt contained lithium metal) in the
Measured category representing an increase of 221% in tonnes and 133% in
contained metal in the Measured category compared with the February 2024 MRE.
· The Project now has sufficient material in Measured category alone to
support over 20 years of production. This is a major milestone as it further
de-risks the resource and adds a higher level of confidence in the detailed
mine plan, which is key to future financing plans.
· The increase in the Measured category is contained exclusively within
the broad mineralised zone, which comprises mineralised internal greisen and
lower grade mineralised albite granite.
· The inclusion of the additional Measured category within the
mineralised zone is as a result of Zinnwald Lithium carrying out metallurgical
testwork on 35 variability drill core samples derived from the 2022 / 2023
drilling campaign. This was a recommendation by Snowden Optiro following the
previous February 2024 MRE.
· The total Measured category is increased to 36.3Mt @ 2,500ppm Li
(91kt contained lithium metal) while the total Indicated category is now
157.2Mt @ 2,150ppm Li (337kt contained lithium metal) as a result of the
increase in the Measured category. The total Measured and Indicated category
remains unchanged at 193.5Mt @ 2,220ppm Li (428kt contained lithium metal).
· The Inferred category remains unchanged at 33.3Mt @ 2,140ppm Li (71kt
contained lithium metal).
Zinnwald Lithium CEO, Anton du Plessis, commented: "We are delighted to
announce substantially improved confidence in the Mineral Resource at the
Zinnwald Project with a 3.2x increase in resource tonnes in the Measured
category. The significant size of the measured resource coupled with the
improved continuity underscores the potential for the Project to support
materially increased production rates using large scale bulk underground
mining techniques compared with what was contemplated in the 2022 Preliminary
Economic Assessment."
DETAILS
The Project's previous update to its MRE, announced on 21 February 2024,
showed it was the second largest hard-rock resource in the EU. The Company
undertook a further geometallurgical testwork programme to provide a higher
level of confidence in the Mineral Resource within the broader mineralisation
zone. This has resulted in an additional 25.0Mt being included in the Measured
category. This represents a 221% increase in tonnage and a 133% increase in
contained lithium within the Measured category compared to the February 2024
MRE. The Project now has sufficient material in Measured category alone to
support over 20 years of production. This is a major milestone as it further
de-risks the resource and adds a higher level of confidence in the detailed
mine plan, which is key to financing plans.
This June 2024 MRE update does not incorporate any new drilling or sampling
data, and as such, the block model estimate is unchanged. The February 2024
MRE incorporated 26,911m of new diamond core drilling across 84 drill holes
completed since the previous MRE released in September 2018. The corresponding
drill hole database now consists of 33,933m of drill core and 19,537 samples
with lithium analyses since the Project started in 2011.
In addition to the high-grade greisen mineralisation, the focus of the recent
2022 / 2023 drilling was the lithium mineralisation hosted by the mineralised
albite granite, as well as the internal lenses of higher grade greisen (termed
the mineralised zone). The inclusion of the mineralised zone allows for a
higher production rate and a potential optimisation of overall project
economics.
The following statement of Mineral Resources has been prepared in accordance
with National Instrument 43-101 Standards of Disclosure for Mineral Projects
of the Canadian Securities Administrators ("NI 43-101") by independent
consulting firm Snowden Optiro Ltd ("Datamine International") of Bristol,
United Kingdom.
Table 1.1: Mineral Resource Statement for Zinnwald Lithium Project, effective
5 June 2024.
Classification Domain Tonnes Mean grade Contained metal
(Mt)
Li (ppm) Li(2)O (%) Li (kt) LCE (kt)
Measured External Greisen (1) 11.3 3,420 0.736 39 206
Mineralised Zone (2) 25.0 2,090 0.449 52 277
· Internal Greisen 1.5 3,240 0.697 5 27
· Mineralised Granite 23.5 2,020 0.434 47 250
Subtotal (1) and (2) 36.3 2,500 0.538 91 483
Indicated External Greisen (1) 2.1 3,510 0.756 7 40
Mineralised Zone (2) 155.1 2,130 0.459 331 1,762
· Internal Greisen 13.2 3,330 0.717 44 234
· Mineralised Granite 141.9 2,019 0.435 287 1,528
Subtotal (1) and (2) 157.2 2,150 0.463 338 1,802
Measured + Indicated subtotal 193.5 2,220 0.478 429 2,285
Inferred External Greisen (1) 0.8 3,510 0.756 3 15
Mineralised Zone (2) 32.5 2,110 0.454 68 364
· Internal Greisen 0.6 2,880 0.620 2 9
· Mineralised Granite 31.9 2,090 0.450 67 355
Subtotal (1) and (2) 33.3 2,140 0.461 71 379
Inferred subtotal 33.3 2,140 0.461 71 379
Notes
· Mineral Resource statement has an effective date of [5th June
2024].
· A Mineral Resource is reported using a cut-off grade of 1,100 ppm
Li, which was calculated using the following assumptions: lithium hydroxide
monohydrate price USD 23,800 /t, operating costs of USD $ 121.5/ t ROM; Li
recovery of 69%; mining dilution and recovery of 10%.
· The requirement of a reasonable prospect of eventual economic
extraction is met by having a minimum modelling width for mineralized zones, a
cut-off grade based on reasonable inputs and an economic binding volume that
lends itself to a potential scenario of underground extraction for undiluted
in-situ resources.
· The Mineral Resource is reported at a minimum of 20m below
historical underground mine workings (to avoid historic underground workings),
and within Germany only.
· All tonnages reported are dry metric tonnes.
· Minor discrepancies may occur due to rounding and use of
appropriate significant figures.
· LCE (lithium carbonate equivalent) calculation used - 5.323 x Li
metal. LiOH*H2O (lithium hydroxide monohydrate) calculation used - 6.045 x Li
Metal.
· Mineral resources which are not mineral reserves do not have
demonstrated economic viability. An Inferred Mineral Resource has a lower
level of confidence than that applying to an Indicated Mineral Resource and
must not be converted to a Mineral Reserve. It is reasonably expected that the
majority of Inferred Mineral Resources could be upgraded to Indicated Mineral
Resources with continued exploration.
· The results from the stope optimisation are used solely for the
purpose of testing the "reasonable prospects for economic extraction" by
underground methods and do not represent an attempt to estimate mineral
reserves. There are no mineral reserves reported in this NI 43-101 resource
update. The results are used as a guide to assist in the preparation of a
Mineral Resource statement and to select an appropriate resource reporting
cut-off grade. Stope optimisation does not represent an economic study.
· The estimate of Mineral Resources may be materially affected by
environmental, permitting, legal, title, taxation, socio-political, marketing,
or other relevant issues.
· The Author is not aware of any known mining, processing,
metallurgical, environmental, infrastructure, economic, permitting, legal,
title, taxation, socio-political, or marketing issues, or any other relevant
factors, that could materially affect the current Mineral Resource Estimate.
Project Overview
Snowden Optiro was commissioned by Zinnwald Lithium plc to undertake a
re-classification of the MRE of the Zinnwald Lithium deposit following an
update to the MRE in February 2024.
The Zinnwald Lithium project is located in Saxony, Germany, very close to the
German-Czech Republic border (Figure 1.1). The Zinnwald Lithium deposit is a
typical greisen-hosted deposit and is located within the Central European
Variscan (Hercynican) belt. The primary ore mineral for the deposit is the
type locality for the mica mineral known as Zinnwaldite, which can contain up
to 1.9 wt.% lithium.
Figure 1.1: Zinnwald Lithium project location.
Source: Zinnwald Lithium
Mineral Resource Estimate
Zinnwald Lithium announced an updated MRE on 21 February 2024. This followed
Zinnwald Lithium completing an infill drilling campaign in 2022 / 2023. This
June 2024 update to the MRE is a re-classification of the 21 February 2024 MRE
only. No new drilling or sampling data has been incorporated into the block
model and no re-estimation has taken place.
May 2024 Geometallurgical Testwork
The February 2024 MRE reviewed all historic testwork completed on the Zinnwald
deposit, which included bench scale and pilot scale testwork. Whilst the
Qualified Person was satisfied that sufficient bulk metallurgical testing,
including a pilot plant test, has been performed on both the greisen and
mineralised granite domain, sufficient work had not been carried out to test
for geological / mineralogical variation and how these variabilities affect
metallurgical performance. The mineralised albite granite is mineralogically
and geologically more heterogeneous compared with the greisens and it was
determined that insufficient variability testing had been performed to date.
Following this review, Snowden Optiro recommended that Zinnwald Lithium
conduct a geo-metallurgical testwork programme, comprising processing testwork
and an accompanying qualitative and quantitative mineralogical study.
Understanding variability in alteration of the host rock and zinnwaldite and
its potential effect on processing performance was the direct objective of the
testwork programme. The proposed Zinnwald flowsheet is basic and the primary
and only recovery process is magnetic separation, which relies on the magnetic
susceptibility of the ore mineral (zinnwaldite), and by extension the iron
content of the ore mineral. Any variations in iron content may affect magnetic
susceptibility and recoveries / grade of the concentrate.
The Qualified Person selected a total of 35 drill core samples for the
purposes of the geometallurgical testwork programme. The testwork programme
was designed at bench scale and incorporated the concentrator portion of the
overall Zinnwald flowsheet. It was deemed that the concentrator flowsheet and
concentrate recoveries were more susceptible to variations in feed than the
pyro / hydro-metallurgical flow sheet.
The objective of the study was to test geological variability, primarily
within the mineralised albite granite, but also within the internal and
external greisens.
The laboratory scale testwork was conducted by Metso at the Research Centre in
Pori, Finland. This facility has also been used by Metso for other Zinnwald
Lithium testwork campaigns. The flowsheet was designed to replicate the
proposed full-scale process, as close as reasonably possible. The sample
preparation and the use of a SLon magnet mirrored the 2023 / 2024 pilot scale
testwork campaign conducted by Metso.
The main findings from the geometallurgical testwork were:
· Variability in lithium recoveries exists in the mineralised albite
granite samples (45.8% - 81.1%), with a mean of 64.5%.
· Lower variability in lithium recoveries exist in the greisen samples.
No differentiation in recoveries can be determined between the internal
(within the mineralised zone) and external greisens.
· Variation in recoveries appears to be associated with chlorite /
sericite alteration (and to a lesser extent kaolinisation) of the albite
granite, with the former potentially associated with zinnwaldite alteration.
Conversely unaltered and haematised albite granite exhibits lower variability
in recoveries.
Subsequent modelling of the alteration zones within the deposit demonstrate
that alteration is not common and that it is often constrained to narrow
joints and fault structures. Distribution is often disparate but occasionally
forms broad zones that centre around major faults and continuous greisens /
joints. Interrogation of the models confirms that approximately 20% of the
mineralised albite granite domain is altered, inferring that approximately 20%
of the mineralised albite granite will exhibit variable processing
performance, due to host rock kaolinisation and host mineral alteration.
February 2024 Mineral Resource estimate
This Mineral Resource estimate required a reinterpretation and an updated
geological model in order to represent the geological and mineralogical
domains that have been defined by the most recent drilling campaign undertaken
by Zinnwald Lithium during 2022 and 2023. The geological model includes
mineralisation domains that are represented by the higher grade greisens
"external", as well as a broader zone of lithium mineralisation contained
within a mineralised albite lithium mica granite and "internal" higher grade
greisens. The higher-grade external greisens are narrow in places but can
reach up to 40m in true thickness and outcrop above the mineralised zone of
granite and internal greisens with a typical separation but variable distance
of approximately 10m. The broader mineralised zone has an average true
thickness of approximately 80m and contains lenses of greisen that locally
exhibit higher grades of lithium mineralisation. Both the mineralisation zone
and the greisens mirror the strike and dip of the host rock intrusion- the
albite granite, as is typical of many greisen related roof zone deposits.
Lithium mineralisation within all geological domains is hosted exclusively by
polylithionite micas, or better known as "zinnwaldite" type micas.
Lithium has been estimated using ordinary kriging methods, and density using
simple kriging methods. Estimation has honoured the hard boundaries of the
external greisens, internal greisens and mineralised granite domains, as well
as using a dynamic anisotropic search method to honour the varying dip and dip
directions of all estimation domains (Figure 1.2, Figure 1.3 and Figure 1.4).
Figure 1.2: 3D view looking north west. Mineral Resource block model showing
distribution of lithium metal (Li_ppm) grades.
Block model showing lithium (Li_ppm) grade distribution.
Figure 1.3: N-S long section through the resource block model.
Block model showing lithium (Li_ppm) grade distribution, red line denotes
reportable limit as defined by a 20m safety pillar below historical mine
workings, black line denotes topography.
Figure 1.4: W-E cross section through the resource block model.
Block model showing lithium (Li_ppm) grade distribution, red line denotes
reportable limit as defined by a 20m safety pillar below historical mine
workings, black line denotes topography.
Classification
Snowden Optiro has taken multiple factors into account when considering
classification:
· Drillhole spacing
· Geological model confidence
· Mineralisation continuity
· Metallurgical confidence
· Estimation pass
· Mineralisation thickness
The classification criteria for the resource are as follows:
Measured:
· External greisen units, below the 20m safety buffer, showing
consistently mineralised zones supported by several drilling intersections at
a spacing of approximately 80m. This corresponds to parts of the model where
the geo-metallurgical behaviour is well understood, and the mineralisation
shows suitable continuity. The classification does not include any
extrapolated material beyond appropriately spaced drillholes and must be
estimated in the first search pass.
· Mineralised zone, below the 20m safety buffer, showing consistently
mineralised zones supported by several drilling intersections at a spacing of
approximately 80m. This corresponds to parts of the model where the
geo-metallurgical behaviour is well understood, and the mineralisation shows
suitable continuity. Only zones of modelled unaltered granite have been
included in the Measured category. The classification does not include any
extrapolated material beyond appropriately spaced drillholes and must be
estimated in the first search pass.
Indicated:
· External greisen units, below the 20m safety buffer, supported by
drilling intersections on a spacing of 80-120m. The classification does not
include any extrapolated material beyond appropriately spaced drillholes and
must be estimated in the first search pass.
· Mineralised zone, below the 20m safety buffer, supported by drilling
intersections on a spacing of 80-120m or at approximately 80m in zones of the
domain that have been modelled as exhibiting alteration (kaolinisation /
zinnwaldite alteration). The classification does not include any extrapolated
material beyond appropriately spaced drillholes and must be estimated in the
first search pass.
Inferred:
· External greisen units and the mineralisation zone, below the 20m
safety buffer, supported by wider-spaced drilling. This corresponds to less
certainty in geological / mineralisation continuity and consists of material
estimated in the first and second pass and extrapolated beyond drillholes at
the periphery of the model up to half drillhole spacing.
Snowden Optiro has recommended to Zinnwald Lithium that a further
geometallurgical testwork programme be undertaken within the modelled
alteration zones of the mineralised granite in order to provide a higher level
of confidence in the Mineral Resource within the broader mineralisation zone.
This is as a result of the 2024 geometallurgical testwork demonstrating a high
variability in processing performance within the altered zones of the
mineralised granite.
Reasonable Prospects for Eventual Economic Extraction
NI 43-101 defines a mineral resource as that portion of the mineral inventory
that has reasonable prospects for economic extraction (RPEEE). CIM Best
Practice Guidelines for estimating mineral resources require the factors
significant to project economics be current, reasonably developed and based on
generally accepted industry practice and experience. In establishing the
cut-off grade, it must realistically reflect the location, deposit scale,
continuity, assumed mining method, metallurgical processes, costs and
reasonable long-term metal prices appropriate for the deposit.
Key assumptions have been provided to Snowden Optiro by Zinnwald Lithium for
this MRE; these have been adjusted in accordance with the Company's
understanding of costs associated with a higher production rate expected when
mining a greater volume of material at a lower grade. This includes
metallurgical recoveries and mineral processing costs based on the results of
ongoing metallurgical testwork.
The grade-tonnage curve in Figure 1.5 demonstrates the robustness of the
estimation to changes in cut-off grade around the 1,100 ppm Li grade.
Figure 1.5: Grade-tonnage curve for the Zinnwald Lithium deposit, Measured and Indicated only.
Comparison with Previous Estimates
The most recent MRE for the deposit was completed on the 20 February 2024 by
Snowden Optiro and was prepared and reported in accordance with National
Instrument 43-101 - Standards of Disclosure for Mineral Projects ("NI
43-101"). The June 2024 MRE is an update to the February 2024 MRE and does not
include a re-estimate, with the only material difference being a
re-classification. A direct comparison is provided in Table 1.3.
Table 1.3: Comparison of the Snowden Optiro Feb 2024 MRE with the updated
Snowden Optiro June 2024 MRE
Model Classification Type Tonnes Mean Grade Contained Metal
(Mt) Li (ppm) Li (kt)
Snowden Optiro (Feb 2024) Measured External Greisen (1) 11.3 3,420 39
Mineralised Zone (2) - - -
Indicated External Greisen (1) 2.1 3,510 7
Mineralised Zone (2) 180.0 2,120 383
Measured + Indicated 193.5 2,220 429
Inferred External Greisen (1) 0.8 3,510 3
Mineralised Zone (2) 32.5 2,110 68
Snowden Optiro (June 2024) Measured External Greisen (1) 11.3 3,420 39
Mineralised Zone (2) 25.0 2,090 52
Indicated External Greisen (1) 2.1 3,510 7
Mineralised Zone (2) 155.1 2,130 331
Measured + Indicated 193.5 2,220 429
Inferred External Greisen (1) 0.8 3,510 3
Mineralised Zone (2) 32.5 2,110 68
Cut-off grade used for the Feb and June 2024 MRE was 1,100ppm.
The June 2024 MRE shows a 25Mt increase in the Measured category compared with
the February 2024 MRE. This is as a result of better understanding processing
performance variability and the relationship with variability of the deposit.
Resultant alteration modelling within the mineralised granite has helped guide
classification of Measured in regions of unaltered mineralised albite granite
only. A drop in the Indicated category is as a result of the increase in the
Measured category. No changes were made to the Inferred category.
Snowden Optiro has recommended to Zinnwald Lithium that further
geometallurgical testing of alteration zones of the mineralised albite granite
be undertaken in order to convert parts of the Resource currently defined as
Indicated.
Qualified Persons
Laurie Hassall, Senior Consultant, MSci FIMMM '689775' FGS '1044219', of
Snowden Optiro is the main author of the Technical Report, is responsible for
the technical part of this announcement and is a Qualified Person under the
terms of NI 43-101.
The technical disclosure in this announcement has been approved by Qualified
Person EurGeol (#641) Christian Masurenko of Zinnwald Lithium, Dipl. Geo.,
Member EFG, Fellow SEG
*ENDS*
For further information visit www.zinnwaldlithium.com or contact:
Anton du Plessis Zinnwald Lithium plc info@zinnwaldlithium.com (mailto:info@zinnwaldlithium.com)
Cherif Rifaat
David Hart Allenby Capital +44 (0) 20 3328 5656
Dan Dearden-Williams (Nominated Adviser)
Michael Seabrook Oberon Capital Ltd +44 (0) 20 3179 5300
Adam Pollock (Joint Broker)
Richard Greenfield Tamesis Partner LLP +44 (0) 20 3882 2868
Charles Bendon (Joint Broker)
Isabel de Salis St Brides Partners zinnwald@stbridespartners.co.uk (mailto:zinnwald@stbridespartners.co.uk)
Paul Dulieu (Financial PR)
Notes
AIM quoted Zinnwald Lithium plc (EPIC: ZNWD.L) is focused on becoming an
important supplier of lithium hydroxide to Europe's fast-growing battery
sector. The Company owns 100% of the Zinnwald Lithium Project in Germany,
which has an approved mining licence, is located in the heart of Europe's
chemical and automotive industries and has the potential to be one of Europe's
more advanced battery grade lithium projects.
Glossary and definition of terms
Title Explanation
Cut-off grade The lowest grade or quality of mineralized material that qualifies as
economically mineable and available in a given deposit. May be defined on the
basis of economic evaluation or on physical or chemical attributes that define
an acceptable product specification.
Indicated Mineral Resource That part of a Mineral Resource for which tonnage, densities, shape, physical
characteristics, grade and mineral content can be estimated with a reasonable
level of confidence. It is based sampling and testing information gathered
through appropriate techniques from locations such as outcrops, trenches,
pits, workings and drill holes. The locations are too widely or
inappropriately spaced to confirm geological and/or grade continuity but are
spaced closely enough for continuity to be assumed.
Inferred Mineral Resource That part of a Mineral Resource for which tonnage, densities, shape, physical
characteristics, grade and mineral content can be estimated with a low level
of confidence. It is inferred from geological evidence and assumed but not
verified geological and/or grade continuity. It is based on information
gathered through appropriate techniques from locations such as outcrops,
trenches, pits, workings and drill holes that may be limited or of uncertain
quality and reliability.
Measured Mineral Resource That part of a Mineral Resource for which tonnage, densities, shape, physical
characteristics, grade and mineral content can be estimated with a high level
of confidence. It is based on detailed and reliable exploration, sampling
and testing information gathered through appropriate techniques from locations
such as outcrops, trenches, pits, workings and drill holes. The locations
are spaced closely enough to confirm geological and grade continuity.
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