REG - Cobra Resources PLC - ISR Bench Scale Study Delivers Exceptional Results
01/10/2024 07:00
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RNS Number : 3212G Cobra Resources PLC 01 October 2024
THIS ANNOUNCEMENT CONTAINS INSIDE INFORMATION FOR THE PURPOSES OF ARTICLE 7 OF
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1 October 2024
Cobra Resources plc
("Cobra" or the "Company")
ISR Bench Scale Study Delivers Exceptional Results
Supports future operation in the lowest quartile for costs of rare earth
miners globally
Cobra (https://cobraplc.com/) (LSE: COBR)
(https://www.londonstockexchange.com/stock/COBR/cobra-resources-plc/company-page)
, the mineral exploration and development company advancing a potentially
world-class ionic Rare Earth Elements ("REEs") discovery at its Boland Project
in South Australia, is pleased to announce the following results from bench
scale In Situ Recovery ("ISR") trials:
· Bench scale trials have successfully demonstrated the ISR recovery
process - a low-cost mining method with low environmental disturbance
· Strong recoveries - 50% Total Rare Earth Oxides ("TREO") and 48%
valuable Magnet Rare Earth Oxides ("MREO") recovered by lowering the sample pH
from 7.1 to 3.6, a relatively benign adjustment in acidity. This testwork is
ongoing and recoveries are expected to increase
· Further extraction upside - recoveries of up to 84% Neodymium and
Praseodymium ("NdPr") and 88% Dysprosium and Terbium ("DyTb") (some of the key
rare earths underpinning the energy transition) achieved in optimisation tests
with adjustments to lixiviant with minimal impact on impurities and processing
costs
· Low levels of impurities (deleterious elements) and low levels of
acid consumption
Follow this link to watch a short video of CEO Rupert Verco explaining the
results released in this announcement:
https://investors.cobraplc.com/link/oPBwVy
(https://investors.cobraplc.com/link/oPBwVy) . Investors are also invited to
submit any questions from this announcement directly to the management team
via the hub.
Rupert Verco, CEO of Cobra, commented:
"These extremely pleasing results highlight the advantage that the Boland
Project's unique geology presents compared to peers globally. They support a
future operation that could produce critical heavy rare earth metals
sustainably and from a cost base that could be competitive with the lowest
quartile of REE miners globally. As a Company, we do not make that statement
without strong supporting evidence. This year, we aimed to de-risk and
highlight our investment opportunity by:
1. Expanding our already significant land position to over 5,200km(2)
and defining mineralisation over a massive regional footprint
2. Demonstrating mineralisation occurs within permeable geology where
concentrated grades occur up to 0.7% TREO
3. Achieving high recoveries by a low-cost mining and extraction process
that differentiates the Boland Project from others globally
Rare earth projects are complex but the fundamentals that underpin mining
profitability apply: scale, grade, and low capital and operating costs. We are
demonstrating that the Boland Project meets all these fundamentals.
Shareholders can look forward to further news flow as we look to advance the
project towards commercialisation."
Cobra's unique and highly scalable Boland discovery is a strategically
advantageous ionic Rare Earth discovery where high grades of valuable Heavy
Rare Earths ("HREOs") and Magnet Rare Earths ("MREOs") occur concentrated in a
permeable horizon confined by impermeable clays. Bench scale ISR testing has
confirmed that mineralisation is amenable to ISR mining. ISR has been used
successfully for decades within geologically similar systems to recover
uranium within South Australia. Results of this metallurgical test work
support that, with minor optimisation, ISR techniques should enable
non-invasive and low-cost production of critical REEs from Cobra's Boland
discovery.
Cobra engaged the Australian Nuclear Science and Technology Organisation
("ANSTO") to execute a detailed work programme to confirm and optimise the
recovery of REEs through the ISR process. Highlights include:
· Low capital mining process: the permeability of the orebody is used
to percolate lixiviant. A permeation rate of 0.13 pore volumes per day is
being achieved which is comparable to operating ISR uranium mines. This
demonstrates that geological conditions can be used to mitigate the cost of
capital infrastructure for ore handling and processing
· High desorption recoveries to date: rare earths commenced reporting
to solution when the Pregnant Liquor Solution ("PLS") in the column dropped
below pH 5.2 and rapidly continued until the PLS reached its current level of
pH 3.6. Achieved recoveries to date are: 50% TREO, 48% MREO and 43% HREO with
further recoveries expected with increased time
· Further recovery upside: optimisation tests demonstrate that using a
pH 2.0 lixiviant may increase recoveries up to 78% Pr, 86% Nd, 86% Dy and 87%
Tb which have been achieved in diagnostic leaches performed on three composite
samples
· Low acid consumption: total sulphuric acid consumption of 15.0 kg per
tonne of ore treated in column ISR study
· Low impurity levels: low levels of impurities (deleterious elements)
compared to recovered rare earths support a low cost, simple process for
purification
· These extremely pleasing results highlight the advantage that the
Boland Project's unique geology presents compared to peers globally. ISR
removes the need for mine excavation, ore handling, physical processing and
tailings dams whilst reducing environmental disturbance
· Approvals are in place to commence resource drilling as a precursor
to a Scoping Study
Further information relating to metallurgical results are presented in the
appendices.
Enquiries:
Cobra Resources plc via Vigo Consulting
Rupert Verco (Australia) +44 (0)20 7390 0234
Dan Maling (UK)
SI Capital Limited (Joint Broker) +44 (0)1483 413 500
Nick Emerson
Sam Lomanto
Global Investment Strategy (Joint Broker) +44 (0)20 7048 9437
James Sheehan james.sheehan@gisukltd.com
Vigo Consulting (Financial Public Relations) +44 (0)20 7390 0234
Ben Simons cobra@vigoconsulting.com
Kendall Hill
The person who arranged for the release of this announcement was Rupert Verco,
Managing Director of the Company.
Information in this announcement relates to exploration results that have been
reported in the following announcements:
· Wudinna Project Update: "ISR bench scale update - Exceptionally high
recoveries with low impurities and low acid consumption; on path to disrupt
global supply
of heavy rare earths", dated 28 August 2024
· Wudinna Project Update: "ISR bench scale update -Further
metallurgical success at world leading ISR rare earth project", dated 11 July
2024
· Wudinna Project Update: "ISR bench scale update - Exceptional head
grades revealed", dated 18 June 2024
· Wudinna Project Update: "Re-Assay Results Confirm High Grades Over
Exceptional Scale at Boland", dated 26 April 2024
· Wudinna Project Update: "Drilling results from Boland Prospect",
dated 25 March 2024
· Wudinna Project Update: "Historical Drillhole Re-Assay Results",
dated 27 February 2024
· Wudinna Project Update: "Ionic Rare Earth Mineralisation at Boland
Prospect", dated 11 September 2023
· Wudinna Project Update: "Exceptional REE Results Defined at Boland",
dated 20 June 2023
Competent Persons Statement
The information in this report that relates to metallurgical results is based
on information compiled by Cobra Resources and reviewed by Mr Conrad Wilkins
who is the Group Process Engineering Lead at Wallbridge Gilbert Aztec, a
Fellow of the Australian Institute of Mining and Metallurgy (FAusIMM),
Chartered Professional Engineer and Member of Engineers Australia (CPEng
MIEAust). Mr Wilkins has sufficient experience that is relevant to the
metallurgical testing which was undertaken to qualify as a Competent Person as
defined in the 2012 edition of the "Australasian Code for Reporting of
Exploration Results, Mineral Resources and Ore Reserves". Mr Wilkins consents
to the inclusion in this report of the matters based on this information in
the form and context in which it appears.
Information in this announcement has been assessed by Mr Rupert Verco, a
Fellow of the Australasian Institute of Mining and Metallurgy. Mr Verco is an
employee of Cobra and has more than 16 years' industry experience which is
relevant to the style of mineralisation, deposit type, and activity which he
is undertaking to qualify as a Competent Person as defined in the 2012 Edition
of the Australasian Code for Reporting Exploration Results, Mineral Resources
and Ore Reserves of JORC. This includes 12 years of Mining, Resource
Estimation and Exploration.
About Cobra
In 2023, Cobra discovered a rare earth deposit with the potential to re-define
the cost of rare earth production. The highly scalable Boland ionic rare earth
discovery at Cobra's Wudinna Project in South Australia's Gawler Craton is
Australia's only rare earth project amenable for in situ recovery (ISR) mining
- a low cost, low disturbance method. Cobra is focused on de-risking the
investment value of the discovery by proving ISR as the preferred mining
method which would eliminate challenges associated with processing clays and
provide Cobra with the opportunity to define a low-cost pathway to production.
Cobra's Wudinna tenements also contain extensive orogenic gold mineralisation,
including a 279,000 Oz gold JORC Mineral Resource Estimate, characterised by
low levels of over-burden, amenable to open pit mining.
Regional map showing Cobra's tenements in the heart of the Gawler Craton
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Engage with us by asking questions, watching video summaries and seeing what
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Appendix 1: Background information - the Boland Project and ISR
· The Boland Project was discovered by Cobra in 2023. Mineralisation is
ionically bound to clays and organics within Palaeochannel sands within the
Narlaby Palaeochannel
· Mineralisation occurs within a permeable sand within an aquifer that
is saltier than sea water and is confined by impermeable clays
· ISR is executed through engineered drillhole arrays that allow the
injection of mildly acidic ammonium sulphate lixiviants, using the confining
nature of the geology to direct and lower the acidity of the orebody. This low
cost process enables mines to operate profitably at lower grades and lower
rates of recovery
· Once REEs are mobile in solution in groundwater, it is also possible,
from an engineering standpoint, to recover the solution to surface via
extraction drillholes, without any need for excavation or ground disturbance
· The capital costs of ISR mining are low as they involve no material
movements and do not require traditional infrastructure to process ore - i.e.
metals are recovered in solution
· Ionic mineralisation is highly desirable owing to its high weighting
of valuable HREOs and the cost-effective method in which REEs can be desorbed
· Ionic REE mineralisation in China is mined in an in situ manner that
relies on gravity to permeate mineralisation. The style of ISR process is
unconfined and cannot be controlled, increasing the risk for environmental
degradation. This low-cost process has enabled China to dominate mine supply
of HREOs, supplying over 90% globally
· Confined aquifer ISR is successfully executed globally within the
uranium industry, accounting for more than 60% of the world's uranium
production. This style of ISR has temporary ground disturbance, and the ground
waters are regenerated over time
· Cobra is aiming to demonstrate the economic and environmental
benefits of recovering ionic HREOs through the more environmentally aquifer
controlled ISR - a world first for rare earths
Figure 1: Comparison between the Chinese and the proposed Boland process for
ISR mining of REEs
Appendix 2: ISR study process and results
The bench scale ISR study conducted by ANSTO is based on a process routinely
implemented to demonstrate the amenability of uranium ores to be mined via
ISR. ISR is enabled by orebody permeability. These characteristics enable
multiple steps to be removed from the traditional mining and processing. The
objective of the study was to demonstrate and identify optimal parameters in
which ISR could be utilised to minimise the economics of recovering REEs. The
test parameters are scaled to emulate the actual field process. A photograph
of the test sample is detailed in Figure 2.
The ISR process occurs in two phases:
1. Preconditioning: The period where injection and extraction occurs to
impregnate the orebody and modify the acidity of the aquifer. It took
approximately 10 pore volumes (~80 days) to lower the pH from 7.1 to 5.7.
Through this period acid consumption occurred due to the presence of minor
acid consuming minerals. When the PLS pH dropped below pH 5.7, REEs began
reporting to the PLS
2. Extraction: When the acidity reaches a point in which the ion
exchange can occur, REE recovery commences. In this circumstance, this
occurred from pH 5.7. REEs reported to the PLS during 5 pore volumes (~34
days)
Figure 2: ANSTO bench scale ISR test
Results of the study demonstrate:
· Orebody characteristics are amenable to ISR mining - a maximum
permeability rate of 0.16 pore volumes per day which is similar to
permeability rates of operating uranium mines
· Robust ionic REE recoveries of 50% TREO, 48% MREO and 43% HREO
achieved before the PLS pH reached pH 3.5
· Low acid consumption of 15.0 kg/t sulphuric acid (H(2)SO(4))
· High purity REE extraction: low impurity levels that support a simple
purification process. This enables further optimisation to increase
recoveries. PLS impurity concentrations shown in the table below
Table 1: Achieved recoveries in PLS (mg/L) of REE and impurities during the
extraction phase of the ISR process
TREY Th U Al Fe Si
528 0.005 0.07 68 76 41
Figure 3: Cumulative recoveries of REE to PLS plotted against PLS acidity
Optimisation Results
Bench scale results contain low levels of impurities including low levels of
uranium and thorium (radionuclides), therefore there is an opportunity to
increase REE recoveries through lixiviant optimisation. In parallel with the
bench scale ISR test, optimisation analyses have been performed to determine
optimal recovery conditions, whilst maintaining low impurity levels.
Samples from a second core hole (CBSC0002) have been subject to diagnostic
leach tests at varying acidities. Results demonstrate:
· Increasing recoveries with minor increases in acidity
· Maximum recoveries achieved at pH 2 being: 84% Nd, 78% Pr, 86% Dy,
87% Tb from high grade samples
· Minor increases in acid consumption at increased acidity
· Increased impurity levels are offset by increased recoveries of REE
Based on the results of diagnostic tests, in situ recoveries can be increased
by lowering the injected lixiviant pH to 2. Further bench scale tests are
being prepared to test the ability to shorten the preconditioning period and
increase recoveries.
Figure 4: Average recoveries achieved from diagnostic leach tests at pH 2, 2.5
& 3
Table 2: Sample head grades and associated diagnostic recoveries
Hole ID Sample ID Sample Head Grade ppm Lixiviant pH Recoveries %
TREO Nd2O3 Pr6O11 Dy2O3 Tb2O3 TREO Nd2O3 Pr6O11 Dy2O3 Tb2O3 TREY:Al
CBSC0002 CS0004 2,921 448 137 59 10 3 37 38 34 40 39 12.2
CBSC0002 CS0004 3,311 520 152 75 13 2.5 56 64 51 70 71 6.7
CBSC0002 CS0004 3,193 512 146 76 13 2 66 76 62 88 88 17.0
CBSC0002 CS0005 2,795 456 121 66 12 3 33 31 32 26 24 20.1
CBSC0002 CS0005 2,306 381 100 62 11 2.5 68 74 67 69 69 9.3
CBSC0002 CS0005 2,431 416 103 65 11 2 78 86 78 86 87 14.8
CBSC0002 CS0006 1,494 203 64 30 5 3 27 30 25 27 26 12.6
CBSC0002 CS0006 1,494 203 64 30 5 2.5 47 60 48 61 61 9.4
CBSC0002 CS0006 1,586 227 67 33 6 2 58 75 60 84 85 11.3
Appendix 3: JORC Code, 2012 Edition - Table 1
Criteria JORC Code explanation Commentary
Sampling techniques · Nature and quality of sampling (eg cut channels, random chips, or 2023
specific specialised industry standard measurement tools appropriate to the
minerals under investigation, such as down hole gamma sondes, or handheld XRF RC
instruments, etc). These examples should not be taken as limiting the broad
meaning of sampling. · Samples were collected via a Metzke cone splitter mounted to the
cyclone. 1m samples were managed through chute and butterfly valve to produce
· Include reference to measures taken to ensure sample representivity a 2-4 kg sample. Samples were taken from the point of collar, but only samples
and the appropriate calibration of any measurement tools or systems used. from the commencement of saprolite were selected for analysis.
· Aspects of the determination of mineralisation that are Material to · Samples submitted to Bureau Veritas Laboratories, Adelaide, and
the Public Report. pulverised to produce the 50 g fire assay charge and 4 acid digest sample.
· In cases where 'industry standard' work has been done this would be
relatively simple (eg 'reverse circulation drilling was used to obtain 1 m
samples from which 3 kg was pulverised to produce a 30 g charge for fire AC
assay'). In other cases more explanation may be required, such as where there
is coarse gold that has inherent sampling problems. Unusual commodities or · A combination of 2m and 3 m samples were collected in green bags
mineralisation types (eg submarine nodules) may warrant disclosure of detailed via a rig mounted cyclone. An PVC spear was used to collect a 2-4 kg sub
information. sample from each green bag. Samples were taken from the point of collar.
· Samples submitted to Bureau Veritas Laboratories, Adelaide, and
pulverised to produce the 50 g fire assay charge and 4 acid digest sample.
2024
SONIC
· Core was scanned by a SciAps X555 pXRF to determine sample
intervals. Intervals through mineralized zones were taken at 10cm. Through
waste, sample intervals were lengthened to 50cm. Core was halved by knife
cutting. XRF scan locations were taken on an inner surface of the core to
ensure readings were taken on fresh sample faces.
Full core samples were submitted to Australian Nuclear Science and Technology
Organisation (ANSTO), Sydney for XRF analysis and to ALS Geochemistry
Laboratory (Brisbane) on behalf of ANSTO for lithium tetraborate digest
ICP-MS. The core was split in half along the vertical axis, and one half
further split into 10 even fractions along the length of the half-core.
Additional sub-sampling, homogenisation and drying steps were performed to
generate ~260 g (dry equivalent) samples for head assay according to the
laboratory internal protocols.
Drilling techniques · Drill type (eg core, reverse circulation, open-hole hammer, rotary 2023
air blast, auger, Bangka, sonic, etc) and details (eg core diameter, triple or
standard tube, depth of diamond tails, face-sampling bit or other type, · Drilling completed by Bullion Drilling Pty Ltd using 5 ¾"
whether core is oriented and if so, by what method, etc). reverse circulation drilling techniques from a Schramm T685WS rig with an
auxiliary compressor.
· Drilling completed by McLeod Drilling Pty Ltd using 75.7 mm NQ
air core drilling techniques from an ALMET Aircore rig mounted on a Toyota
Landcruiser 6x6 and a 200psi, 400cfm Sullair compressor.
2024
· Sonic Core drilling completed Star Drilling using 4" core with a
SDR12 drill rig. Holes were reamed to 6" or 8" to enable casing and screens to
be installed
Drill sample recovery · Method of recording and assessing core and chip sample recoveries and Aircore & RC
results assessed.
· Sample recovery was generally good. All samples were recorded for
· Measures taken to maximise sample recovery and ensure representative sample type, quality and contamination potential and entered within a sample
nature of the samples. log.
· Whether a relationship exists between sample recovery and grade and · In general, sample recoveries were good with 10 kg for each 1 m
whether sample bias may have occurred due to preferential loss/gain of interval being recovered from AC drilling.
fine/coarse material.
· No relationships between sample recovery and grade have been
identified.
· RC drilling completed by Bullion Drilling Pty Ltd using 5 ¾"
reverse circulation drilling techniques from a Schramm T685WS rig with an
auxiliary compressor
· Sample recovery for RC was generally good. All samples were
recorded for sample type, quality and contamination potential and entered
within a sample log.
· In general, RC sample recoveries were good with 35-50 kg for each
1 m interval being recovered.
· No relationships between sample recovery and grade have been
identified.
Sonic Core
· Sample recovery is considered excellent.
Logging · Whether core and chip samples have been geologically and Aircore & RC
geotechnically logged to a level of detail to support appropriate Mineral
Resource estimation, mining studies and metallurgical studies.
· Whether logging is qualitative or quantitative in nature. Core (or · All drill samples were logged by an experienced geologist at the
costean, channel, etc) photography. time of drilling. Lithology, colour, weathering and moisture were documented.
· The total length and percentage of the relevant intersections logged. · Logging is generally qualitative in nature.
· All drill metres have been geologically logged on sample
intervals (1-3 m).
Sonic Core
· Logging was carried out in detail, determining lithology and
clay/ sand content. Logging intervals were lithology based with variable
interval lengths.
· All core drilled has been lithologically logged.
Sub-sampling techniques and sample preparation · If core, whether cut or sawn and whether quarter, half or all core 2021-onward
taken.
· The use of an aluminum scoop or PVC spear to collect the required
· If non-core, whether riffled, tube sampled, rotary split, etc and 2-4 kg of sub-sample from each AC sample length controlled the sample volume
whether sampled wet or dry. submitted to the laboratory.
· For all sample types, the nature, quality and appropriateness of the · Additional sub-sampling was performed through the preparation and
sample preparation technique. processing of samples according to the lab internal protocols.
· Quality control procedures adopted for all sub-sampling stages to · Duplicate AC samples were collected from the green bags using an
maximise representivity of samples. aluminium scoop or PVC spear at a 1 in 25 sample frequency.
· Measures taken to ensure that the sampling is representative of the · Sample sizes were appropriate for the material being sampled.
in situ material collected, including for instance results for field
duplicate/second-half sampling. · Assessment of duplicate results indicated this sub-sample method
provided good repeatability for rare earth elements.
· Whether sample sizes are appropriate to the grain size of the
material being sampled. · RC drill samples were sub-sampled using a cyclone rig mounted
splitter with recoveries monitored using a field spring scale.
· Manual re-splitting of RC samples through a riffle splitter was
undertaken where sample sizes exceeded 4 kg.
· RC field duplicate samples were taken nominally every 1 in 25
samples. These samples showed good repeatability for REE.
Sonic Drilling
· Field duplicate samples were taken nominally every 1 in 25
samples where the sampled interval was quartered.
· Blanks and Standards were submitted every 25 samples
· Half core samples were taken where lab geochemistry sample were
taken.
· In holes where column leach test samples have been submitted,
full core samples have been submitted over the test areas.
Quality of assay data and laboratory tests · The nature, quality and appropriateness of the assaying and Sample Characterisation Test Work performed by the Australian Nuclear Science
laboratory procedures used and whether the technique is considered partial or and Technology Organisation (ANSTO)
total.
· For geophysical tools, spectrometers, handheld XRF instruments, etc,
the parameters used in determining the analysis including instrument make and · Full core samples were submitted to Australian Nuclear Science
model, reading times, calibrations factors applied and their derivation, etc. and Technology Organisation (ANSTO), Sydney for preparation and analysis. The
core was split in half along the vertical axis, and one half further split
· Nature of quality control procedures adopted (eg standards, blanks, into 10 even fractions along the length of the half-core. Additional
duplicates, external laboratory checks) and whether acceptable levels of sub-sampling, homogenisation and drying steps were performed to generate ~260
accuracy (ie lack of bias) and precision have been established. g (dry equivalent) samples for head assay according to the laboratory internal
protocols.
· Multi element geochemistry of solid samples were analysed at
ANSTO (Sydney) by XRF for the major gangue elements Al, Ca, Fe, K, Mg, Mn, Na,
Ni, P, Si, S, and Zn.
· Multi element geochemistry of solid samples were additionally
analysed at ALS Geochemistry Laboratory (Brisbane) on behalf of ANSTO by
lithium tetraborate digest ICP-MS and analysed for Ce, Dy, Er, Eu, Gd, Ho,
La, Lu, Nd, Pr, Sm, Tb, Th, Tm, U, Y and Yb.
· Reported assays are to acceptable levels of accuracy and
precision.
· Internal laboratory blanks, standards and repeats for rare earths
indicated acceptable assay accuracy.
· Samples retained for metallurgical analysis were immediately
vacuum packed, nitrogen purged and refrigerated.
· These samples were refrigerated throughout transport.
Metallurgical Leach Test Work performed by the Australian Nuclear Science and
Technology Organisation (ANSTO)
· ANSTO laboratories prepared ~80g samples for diagnostic leaches, a
443g sample for a slurry leach and a 660g sample for a column leach.
Sub-samples were prepared from full cores according to the laboratory internal
protocols. Diagnostic and slurry leaching were carried out in baffled leach
vessels equipped with an overhead stirrer and applying a 0.5 M (NH4)2SO4
lixiviant solution, adjusted to the select pH using H2SO4.
· 1 M H2SO4 was utilised to maintain the test pH for the duration of
the test, if necessary. The acid addition was measured.
· Thief liquor samples were taken periodically.
· At the completion of each test, the final pH was measured, the slurry
was vacuum filtered to separate the primary filtrate.
· The thief samples and primary filtrate were analysed as follows:
o ICP-MS for Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Mn, Nd, Pb, Pr, Sc, Sm, Tb, Th,
Tm, U, Y, Yb.
o ICP-OES for Al, Ca, Fe, K, Mg, Mn, Na, Si.
· The water wash was stored but not analysed.
· Column leaching was carried out in horizontal leaching column. The
column was pressurised with nitrogen to 6 bar and submerged in a temperature
controlled bath.
· A 0.5 M (NH4)2SO4 lixiviant solution, adjusted to the select pH using
H2SO4 was fed to the column at a controlled flowrate.
· PLS collected from the end of the column was weighed, the SH and pH
measured and the free acid concentration determined by titration. Liquor
samples were taken from the collected PLS and analysed as follows:
o ICP-MS for Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Mn, Nd, Pb, Pr, Sc, Sm, Tb, Th,
Tm, U, Y, Yb.
o ICP-OES for Al, Ca, Fe, K, Mg, Mn, Na, Si.
· The column leach test is still operational.
Verification of sampling and assaying · The verification of significant intersections by either independent · Sampling data was recorded in field books, checked upon
or alternative company personnel. digitising and transferred to database.
· The use of twinned holes. · Geological logging was undertaken digitally via the MX Deposit
logging interface and synchronised to the database at least daily during the
· Documentation of primary data, data entry procedures, data drill programme.
verification, data storage (physical and electronic) protocols.
· Compositing of assays was undertaken and reviewed by Cobra
· Discuss any adjustment to assay data. Resources staff.
· Original copies of laboratory assay data are retained digitally
on the Cobra Resources server for future reference.
· Samples have been spatially verified through the use of Datamine
and Leapfrog geological software for pre 2021 and post 2021 samples and
assays.
· Twinned drillholes from pre 2021 and post 2021 drill programmes
showed acceptable spatial and grade repeatability.
· Physical copies of field sampling books are retained by Cobra
Resources for future reference.
· Elevated pXRF grades were checked and re-tested where anomalous.
pXRF grades are semi quantitative.
Location of data points · Accuracy and quality of surveys used to locate drill holes (collar Pre 2021
and down-hole surveys), trenches, mine workings and other locations used in
Mineral Resource estimation. · Collar locations were pegged using DGPS to an accuracy of +/-0.5
m.
· Specification of the grid system used.
· Downhole surveys have been completed for deeper RC and diamond
· Quality and adequacy of topographic control. drillholes
· Collars have been picked up in a variety of coordinate systems
but have all been converted to MGA 94 Zone 53. Collars have been spatially
verified in the field.
· Collar elevations were historically projected to a geophysical
survey DTM. This survey has been adjusted to AHD using a Leica CS20 GNSS base
and rover survey with a 0.05 cm accuracy. Collar points have been re-projected
to the AHD adjusted topographical surface.
2021-onward
· Collar locations were initially surveyed using a mobile phone
utilising the Avenza Map app. Collar points recorded with a GPS horizontal
accuracy within 5 m.
· RC Collar locations were picked up using a Leica CS20 base and
Rover with an instrument precision of 0.05 cm accuracy.
· Locations are recorded in geodetic datum GDA 94 zone 53.
· No downhole surveying was undertaken on AC holes. All holes were
set up vertically and are assumed vertical.
· RC holes have been down hole surveyed using a Reflex TN-14 true
north seeking downhole survey tool or Reflex multishot
· Downhole surveys were assessed for quality prior to export of
data. Poor quality surveys were downgraded in the database to be excluded from
export.
· All surveys are corrected to MGA 94 Zone 53 within the MX Deposit
database.
· Cased collars of sonic drilling shall be surveyed before a
mineral resource estimate
Data spacing and distribution · Data spacing for reporting of Exploration Results. · Drillhole spacing was designed on transects 50-80 m apart.
Drillholes generally 50-60 m apart on these transects but up to 70 m apart.
· Whether the data spacing and distribution is sufficient to establish
the degree of geological and grade continuity appropriate for the Mineral · Additional scouting holes were drilled opportunistically on
Resource and Ore Reserve estimation procedure(s) and classifications applied. existing tracks at spacings 25-150 m from previous drillholes.
· Whether sample compositing has been applied. · Regional scouting holes are drilled at variable spacings designed
to test structural concepts
· Data spacing is considered adequate for a saprolite hosted rare
earth Mineral Resource estimation.
· No sample compositing has been applied
· Sonic core holes were drilled at ~20m spacings in a wellfield
configuration based on assumed permeability potential of the intersected
geology.
Orientation of data in relation to geological structure · Whether the orientation of sampling achieves unbiased sampling of · RC drillholes have been drilled between -60 and -75 degrees at
possible structures and the extent to which this is known, considering the orientations interpreted to appropriately intersect gold mineralisation
deposit type.
· Aircore and Sonic drill holes are vertical.
· 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.
Sample security · The measures taken to ensure sample security. Pre 2021
· Company staff collected or supervised the collection of all
laboratory samples. Samples were transported by a local freight contractor
· No suspicion of historic samples being tampered with at any stage.
· Pulp samples were collected from Challenger Geological Services and
submitted to Intertek Genalysis by Cobra Resources' employees.
2021-onward
· Transport of samples to Adelaide was undertaken by a competent
independent contractor. Samples were packaged in zip tied polyweave bags in
bundles of 5 samples at the drill rig and transported in larger bulka bags by
batch while being transported.
· Refrigerated transport of samples to Sydney was undertaken by a
competent independent contractor. Samples were double bagged, vacuum sealed,
nitrogen purged and placed within PVC piping.
· There is no suspicion of tampering of samples.
Audits or reviews · The results of any audits or reviews of sampling techniques and data. · No laboratory audit or review has been undertaken.
· Genalysis Intertek and BV Laboratories Adelaide are NATA (National
Association of Testing Authorities) accredited laboratory, recognition of
their analytical competence.
Appendix 4: Section 2 reporting of exploration results
Criteria JORC Code explanation Commentary
Mineral tenement and land tenure status · Type, reference name/number, location and ownership including · RC drilling occurred on EL 6131, currently owned 100% by Peninsula
agreements or material issues with third parties such as joint ventures, Resources limited, a wholly owned subsidiary of Andromeda Metals Limited.
partnerships, overriding royalties, native title interests, historical sites,
wilderness or national park and environmental settings. · Alcrest Royalties Australia Pty Ltd retains a 1.5% NSR royalty over
future mineral production from licenses EL6001, EL5953, EL6131, EL6317 and
· The security of the tenure held at the time of reporting along with EL6489.
any known impediments to obtaining a licence to operate in the area.
· Baggy Green, Clarke, Laker and the IOCG targets are located within
Pinkawillinnie Conservation Park. Native Title Agreement has been negotiated
with the NT Claimant and has been registered with the SA Government.
· Aboriginal heritage surveys have been completed over the Baggy Green
Prospect area, with no sites located in the immediate vicinity.
· A Native Title Agreement is in place with the relevant Native Title
party.
Exploration done by other parties · Acknowledgment and appraisal of exploration by other parties. · On-ground exploration completed prior to Andromeda Metals' work was
limited to 400 m spaced soil geochemistry completed by Newcrest Mining Limited
over the Barns prospect.
· Other than the flying of regional airborne geophysics and coarse
spaced ground gravity, there has been no recorded exploration in the vicinity
of the Baggy Green deposit prior to Andromeda Metals' work.
· Paleochannel uranium exploration was undertaken by various parties in
the 1980s and the 2010s around the Boland Prospect. Drilling was primarily
rotary mud with downhole geophysical logging the primary interpretation
method.
Geology · Deposit type, geological setting and style of mineralisation. · The gold and REE deposits are considered to be related to the
structurally controlled basement weathering of epidote- pyrite alteration
related to the 1590 Ma Hiltaba/GRV tectonothermal event.
· Mineralisation has a spatial association with mafic
intrusions/granodiorite alteration and is associated with metasomatic
alteration of host rocks. Epidote alteration associated with gold
mineralisation is REE enriched and believed to be the primary source.
· Rare earth minerals occur within the saprolite horizon. XRD analysis
by the CSIRO identifies kaolin and montmorillonite as the primary clay phases.
· SEM analysis identified REE bearing mineral phases in hard rock:
· Zircon, titanite, apatite, andradite and epidote.
· SEM analyses identifies the following secondary mineral phases in
saprock:
· Monazite, bastanite, allanite and rutile.
· Elevated phosphates at the base of saprock do not correlate to rare
earth grade peaks.
· Upper saprolite zones do not contain identifiable REE mineral phases,
supporting that the REEs are adsorbed to clay particles.
· Acidity testing by Cobra Resources supports that pH chemistry may act
as a catalyst for Ionic and Colloidal adsorption.
· REE mineral phase change with varying saprolite acidity and REE
abundances support that a component of REE bursary is adsorbed to clays.
· Palaeo drainage has been interpreted from historic drilling and
re-interpretation of EM data that has generated a top of basement model.
· Ionic REE mineralisation is confirmed through metallurgical
desorption testing where high recoveries are achieved at benign acidities
(pH4-3) at ambient temperature.
· Ionic REE mineralisation occurs in reduced clay intervals that
contact both saprolite and permeable sand units. Mineralisation contains
variable sand quantities that is expected
Drillhole Information · A summary of all information material to the understanding of the · Exploration results being reported represent a small portion of the
exploration results including a tabulation of the following information for Boland target area. Coordinates for Wellfield drill holes are presented in
all Material drill holes: Table 3.
o easting and northing of the drill hole collar
o elevation or RL (Reduced Level - elevation above sea level in metres) of
the drill hole collar
o dip and azimuth of the hole
o down hole length and interception depth
o hole length.
· 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.
Data aggregation methods · In reporting Exploration Results, weighting averaging techniques, · Reported summary intercepts are weighted averages based on length.
maximum and/or minimum grade truncations (eg cutting of high grades) and
cut-off grades are usually Material and should be stated. · No maximum/ minimum grade cuts have been applied.
· Where aggregate intercepts incorporate short lengths of high grade · No metal equivalent values have been calculated.
results and longer lengths of low grade results, the procedure used for such
aggregation should be stated and some typical examples of such aggregations · Gold results are reported to a 0.3 g/t cut-off with a maximum of 2m
should be shown in detail. internal dilution with a minimum grade of 0.1 g/t Au.
· The assumptions used for any reporting of metal equivalent values · Rare earth element analyses were originally reported in elemental
should be clearly stated. form and have been converted to relevant oxide concentrations in line with
industry standards. Conversion factors tabulated below:
·
Element Oxide Factor
Cerium CeO(2) 1.2284
Dysprosium Dy(2)O(3) 1.1477
Erbium Er(2)O(3) 1.1435
Europium Eu(2)O(3) 1.1579
Gadolinium Gd(2)O(3) 1.1526
Holmium Ho(2)O(3) 1.1455
Lanthanum La(2)O(3) 1.1728
Lutetium Lu(2)O(3) 1.1371
Neodymium Nd(2)O(3) 1.1664
Praseodymium Pr(6)O(11) 1.2082
Scandium Sc(2)O(3) 1.5338
Samarium Sm(2)O(3) 1.1596
Terbium Tb(4)O(7) 1.1762
Thulium Tm(2)O(3) 1.1421
Yttrium Y(2)O(3) 1.2699
Ytterbium Yb(2)O(3) 1.1387
· The reporting of REE oxides is done so in accordance with industry
standards with the following calculations applied:
· TREO = La(2)O(3) + CeO(2) + Pr(6)O(11) + Nd(2)O(3) + Sm(2)O(3) +
Eu(2)O(3) + Gd(2)O(3) + Tb(4)O(7) + Dy(2)O(3) + Ho(2)O(3) + Er(2)O(3) +
Tm(2)O(3) + Yb(2)O(3) + Lu(2)O(3) + Y(2)O(3)
· CREO = Nd(2)O(3) + Eu(2)O(3) + Tb(4)O(7) + Dy(2)O(3) + Y(2)O(3)
· LREO = La(2)O(3) + CeO(2) + Pr(6)O(11) + Nd(2)O(3)
· HREO = Sm(2)O(3) + Eu(2)O(3) + Gd(2)O(3) + Tb(4)O(7) + Dy(2)O(3)
+ Ho(2)O(3) + Er(2)O(3) + Tm(2)O(3) + Yb(2)O(3) + Lu(2)O(3) + Y(2)O(3)
· MREO = Nd(2)O(3) + Pr(6)O(11) + Tb(4)O(7) + Dy(2)O(3)
· NdPr = Nd(2)O(3) + Pr(6)O(11)
· TREO-Ce = TREO - CeO(2)
· % Nd = Nd(2)O(3)/ TREO
· % Pr = Pr(6)O(11)/TREO
· % Dy = Dy(2)O(3)/TREO
· % HREO = HREO/TREO
· % LREO = LREO/TREO
· XRF results are used as an indication of potential grade only.
Due to detection limits only a combined content of Ce, La, Nd, Pr & Y has
been used. XRF grades have not been converted to oxide.
Relationship between mineralisation widths and intercept lengths · These relationships are particularly important in the reporting of · All reported intercepts at Boland are vertical and reflect true width
Exploration Results. intercepts.
· If the geometry of the mineralisation with respect to the drill hole · Exploration results are not being reported for the Mineral Resource
angle is known, its nature should be reported. area.
· If it is not known and only the down hole lengths are reported, there
should be a clear statement to this effect (eg 'down hole length, true width
not known').
Diagrams · Appropriate maps and sections (with scales) and tabulations of · Relevant diagrams have been included in the announcement.
intercepts should be included for any significant discovery being reported
These should include, but not be limited to a plan view of drill hole collar · Exploration results are not being reported for the Mineral Resources
locations and appropriate sectional views. area.
Balanced reporting · Where comprehensive reporting of all Exploration Results is not · Not applicable - Mineral Resource and Exploration Target are defined.
practicable, representative reporting of both low and high grades and/or
widths should be practiced to avoid misleading reporting of Exploration · Exploration results are not being reported for the Mineral Resource
Results. area.
Other substantive exploration data · Other exploration data, if meaningful and material, should be · Refer to previous announcements listed in RNS for reporting of REE
reported including (but not limited to): geological observations; geophysical results and metallurgical testing
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.
Further work · The nature and scale of planned further work (eg tests for lateral · The metallurgical testing reported in this announcement represents
extensions or depth extensions or large-scale step-out drilling). the first phase of bench scale studies to test the extraction of ionic REEs
via ISR processes.
· Diagrams clearly highlighting the areas of possible extensions,
including the main geological interpretations and future drilling areas, · Future metallurgical testing will focus on producing PLS under leach
provided this information is not commercially sensitive. conditions to conduct downstream bench-scale studies for impurity removal and
product precipitation.
· Hydrology, permeability and mineralogy studies are being performed on
core samples.
· Installed wells are being used to capture hydrology base line data to
support a future infield pilot study.
· Trace line tests shall be performed to emulate bench scale pore
volumes.
· The reporting of REE oxides is done so in accordance with industry
standards with the following calculations applied:
· TREO = La(2)O(3) + CeO(2) + Pr(6)O(11) + Nd(2)O(3) + Sm(2)O(3) +
Eu(2)O(3) + Gd(2)O(3) + Tb(4)O(7) + Dy(2)O(3) + Ho(2)O(3) + Er(2)O(3) +
Tm(2)O(3) + Yb(2)O(3) + Lu(2)O(3) + Y(2)O(3)
· CREO = Nd(2)O(3) + Eu(2)O(3) + Tb(4)O(7) + Dy(2)O(3) + Y(2)O(3)
· LREO = La(2)O(3) + CeO(2) + Pr(6)O(11) + Nd(2)O(3)
· HREO = Sm(2)O(3) + Eu(2)O(3) + Gd(2)O(3) + Tb(4)O(7) + Dy(2)O(3)
+ Ho(2)O(3) + Er(2)O(3) + Tm(2)O(3) + Yb(2)O(3) + Lu(2)O(3) + Y(2)O(3)
· MREO = Nd(2)O(3) + Pr(6)O(11) + Tb(4)O(7) + Dy(2)O(3)
· NdPr = Nd(2)O(3) + Pr(6)O(11)
· TREO-Ce = TREO - CeO(2)
· % Nd = Nd(2)O(3)/ TREO
· % Pr = Pr(6)O(11)/TREO
· % Dy = Dy(2)O(3)/TREO
· % HREO = HREO/TREO
· % LREO = LREO/TREO
· XRF results are used as an indication of potential grade only.
Due to detection limits only a combined content of Ce, La, Nd, Pr & Y has
been used. XRF grades have not been converted to oxide.
Relationship between mineralisation widths and intercept lengths
· These relationships are particularly important in the reporting of
Exploration Results.
· If the geometry of the mineralisation with respect to the drill hole
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 (eg 'down hole length, true width
not known').
· All reported intercepts at Boland are vertical and reflect true width
intercepts.
· Exploration results are not being reported for the Mineral Resource
area.
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 drill hole collar
locations and appropriate sectional views.
· Relevant diagrams have been included in the announcement.
· Exploration results are not being reported for the Mineral Resources
area.
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.
· Not applicable - Mineral Resource and Exploration Target are defined.
· Exploration results are not being reported for the Mineral Resource
area.
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.
· Refer to previous announcements listed in RNS for reporting of REE
results and metallurgical testing
Further work
· The nature and scale of planned further work (eg tests for lateral
extensions or depth extensions or large-scale step-out drilling).
· Diagrams clearly highlighting the areas of possible extensions,
including the main geological interpretations and future drilling areas,
provided this information is not commercially sensitive.
· The metallurgical testing reported in this announcement represents
the first phase of bench scale studies to test the extraction of ionic REEs
via ISR processes.
· Future metallurgical testing will focus on producing PLS under leach
conditions to conduct downstream bench-scale studies for impurity removal and
product precipitation.
· Hydrology, permeability and mineralogy studies are being performed on
core samples.
· Installed wells are being used to capture hydrology base line data to
support a future infield pilot study.
· Trace line tests shall be performed to emulate bench scale pore
volumes.
Table 3: Drillhole coordinates
Prospect Hole number Grid Northing Easting Elevation
Boland CBSC0001 GDA94 / MGA zone 53 6365543 534567 102.9
Boland CBSC0002 GDA94 / MGA zone 53 6365510 534580 104.1
Boland CBSC0003 GDA94 / MGA zone 53 6365521 534554 102.7
Boland CBSC0004 GDA94 / MGA zone 53 6365537 534590 105
Boland CBSC0005 GDA94 / MGA zone 53 6365528 534573 103.2
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