REG - Cobra Resources PLC - Wudinna Project Update
09/01/2023 07:00
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RNS Number : 0157M Cobra Resources PLC 09 January 2023
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9 January 2023
Cobra Resources plc
("Cobra" or the "Company")
Wudinna Project Update
Maiden Rare Earth Resource Estimate - Unique and Unconstrained
Cobra, a gold, rare earth and IOCG exploration company focused on the Wudinna
Project in South Australia, is pleased to announce a maiden Rare Earth
Elements ("REE") JORC Mineral Resource Estimate ("MRE"), enabling a strategic
baseline to advance an economically beneficial combination of gold and rare
earth resources.
Highlights
· Maiden JORC MRE for the Wudinna Project clay-hosted REE of 20.9 Mt at
658 ppm Total Rare Earth Oxides ("TREO")
· The REE Mineral Resource occurs above and proximal to a defined
94,000 Oz gold resource at the Baggy Green prospect and overlies 500m of
intersected gold mineralisation at the Clarke prospect, making this REE
resource and future mining economics unique compared to other clay-hosted REE
projects
· The unique mineral occurrence will enable Cobra to investigate
commercial outcomes for dual commodities
· Defined a sizeable REE Exploration Target at the Thompson prospect
highlights the potential for substantial near-term resource growth
· Initial metallurgical testwork demonstrated magnet rare earth
recoveries of up to 34.7%, whilst follow-up mineralogy and lithological
testwork demonstrates potential for increased recoveries targeting ionic style
mineralisation identified through pH conditions. Mapping and further analysis
work will proof-test this concept, paving the way for resource
re-classification and metallurgical upside
· Upside potential to tonnage and grade owing to downhole composite
lengths of analysed samples across the Baggy Green prospect
· Estimation constrained by extent of current drilling, with extensions
to be tested by planned drilling in coming months
Next Steps
The Company is funded to complete the following work scope to advance the
Wudinna Project towards Feasibility evaluation:
· Metallurgical evaluation of a range of samples selected at varying pH
conditions - an important catalyst for ionic REE adsorption
· Evaluate beneficiation and metallurgical optimisation processes to
enable the development of a commercial flowsheet evaluation
· Further Scanning Electron Microscope ("SEM") analyses to evaluate
quantities of REE mineral phases at various pH conditions
· A drilling programme of 5,000-10,000m scheduled to commence in March
2023, aimed at growing both gold and REE Mineral Resources at Clarke, Barns,
and Thompson prospects
· Update to existing 211,000 Oz gold MRE to incorporate the Clarke
prospect and over 5,000m of additional drilling undertaken across existing
gold Mineral Resource prospects
Rupert Verco, CEO of Cobra, commented:
"Cobra has taken a fundamental step forward in its ambition to develop a
globally unique mineral occurrence by defining a maiden Rare Earth Mineral
Resource Estimate that overlies two growing gold prospects and is
unconstrained.
Not only have we entered the peer group of Australian rare earth resource
holders today, but uniquely we are approaching ours with the economic
advantage of spatial proximity between rare earths and gold. Much of the
spatial occurrence of the rare earth resource overlies gold mineralisation
within the saprolite zone where, should the economics permit open cut mining
methods for gold extraction, we would mine through the defined rare earth
resource, effectively creating value from overburden. The Company considers
the dual mineral occurrences as a globally unique opportunity to devise an
environmentally considerate, low waste ratio, high value resource.
With only limited drilling undertaken to establish this baseline MRE, the
expansion potential given the unconstrained mineralisation is compelling. The
Exploration Target at the Thompson prospect to be drilled in the coming weeks
is of particular interest and could rapidly expand the MRE.
This exceptional result now enables Cobra to advance metallurgical testwork,
grow dual Mineral Resources and commence strategic discussions aimed at
project advancement. Cobra is now poised to expand both gold and rare earth
resources through its 2023 exploration activities to advance the project
towards feasibility studies."
The maiden REE MRE is set out in table 1 below:
Table 1: Wudinna Project maiden JORC Rare Earth Mineral Resource Estimate
Prospect & Category Tonnes TREO MREO LREO HREO Pr(6)O(11) Nd(2)O(3) Dy(2)O(3) Tb(4)O(7)
Mt ppm ppm ppm ppm ppm ppm ppm ppm
Clarke 14.1 685 166 544 141 32.5 116.2 14.7 2.6
Baggy Green 6.8 597 132 453 144 25.7 89.8 14.0 2.3
Total Inferred 20.9 658 155 516 143 30.4 108.0 14.5 2.5
Thompson Exploration Target(1) 81 - 233 640 - 856 168 - 234 550 - 717 97 - 140 32 - 42 124 - 174 10 - 15 2 - 3
Rare Earth Mineral Resources reported at a cut-off grade of 320 ppm TREO-Ce
(1)The conceptual quantity and grade of the Thompson Exploration Target is
conceptual in nature, as there has been insufficient exploration to estimate a
Mineral Resource and it is uncertain if further exploration will result in the
estimation of a Mineral Resource. Consistent with this, all tonnages and
grades are approximations. The Exploration Target is based on wide-spaced
drilling completed to date.
The Wudinna Project comprises a number of shallow, camp scale gold
occurrences. The alteration mineralogy and structural genesis associated with
the gold mineralisation event is believed to act as a catalyst for REE
enrichment and mobilisation. The spatial proximity of rare earth
mineralisation has the potential to economically complement the gold
mineralisation. Additional gold mineralisation has been defined outside of the
existing gold MRE, particularly at Clarke where over 500m of mineralised
strike has been defined and remains an exploration priority to increase the
mineral inventory.
Table 2: 2019 Wudinna Project Gold JORC MRE
Prospect Classification Tonnes Gold g/t Gold ounces
Barns Indicated 410,000 1.4 18,000
Barns Inferred 1,710,000 1.5 86,000
White Tank Inferred 280,000 1.4 13,000
Baggy Green Inferred 2,030,000 1.4 94,000
Total 4,430,000 1.5 211,000
Figure 1: Grade tonnage curve for the maiden Baggy Green and Clarke rare earth
MRE demonstrates the relative relationship between grade and tonnage
distribution. The cut-off grade of 320 ppm TREO-Ce reflects the deflection
point between background and grade enrichment.
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 413500
Nick Emerson
Sam Lomanto
Shard Capital Limited (Joint Broker) +44 (0)20 7186 9952
Erik Woolgar
Damon Heath
Vigo Consulting (Financial Public Relations) +44 (0)20 7390 0234
Ben Simons
Charlie Neish
Kendall Hill
The person who arranged for the release of this announcement was Rupert Verco,
Managing Director of the Company.
About Cobra
Cobra is defining a unique multi-mineral resource at the Wudinna Project in
South Australia's Gawler Craton, a tier one mining and exploration
jurisdiction which hosts several world-class mines. Cobra's Wudinna tenements,
totalling 3,261 km(2), contain extensive orogenic gold mineralisation and are
characterised by potentially open-pitable, high-grade gold intersections, with
ready access to infrastructure. Cobra has 22 orogenic gold targets outside of
the current 211,000 Oz gold JORC Mineral Resource Estimate. In 2021, Cobra
discovered rare earth mineralisation proximal to and above the gold
mineralisation which has been demonstrated to be regionally scalable. In 2023,
Cobra published a maiden rare earth JORC Mineral Resource Estimate of 20.9 Mt
at 658 ppm Total Rare Earth Oxides enabling a strategic baseline to advance an
economically beneficial combination of gold and rare earth resources.
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Competent Persons Statement
The information in this announcement that relates to the estimation and
reporting of Mineral Resources has been compiled by Mrs Christine Standing BSc
Hons (Geology), MSc (Min Econs), MAusIMM, MAIG. Mrs Standing is a full-time
employee of Snowden Optiro (Optiro Pty Ltd) and has acted as an independent
consultant on the Mineral Resource Estimates for the Barns, Baggy Green and
White Tank Deposits. Mrs Standing is a Member of the Australian Institute of
Geoscientists and the Australian Institute of Mining and Metallurgy and has
sufficient experience with the style of mineralisation, deposit type under
consideration and to the activities 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 (The JORC Code).
Mrs Standing consents to the inclusion in this announcement of the contained
technical information relating the Mineral Resource estimations 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 ("FAusIMM"). Mr
Verco an employee of Cobra has more than 16 years' industry experience which
is relevant to the style of mineralisation, deposit type and to the 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 (the "JORC" Code). This includes 11 years
of Mining, Resource Estimation and Exploration.
Information in this announcement relates to exploration results that have been
reported in the following announcements:
· "Wudinna Project Update - Initial Gold and Rare Earth Results",
dated 14 December 2021
· "Wudinna Project Update - Northern Drillholes at Clarke Intersect
Additional Gold Mineralisation, Additional Rare Earth Intersections Directly
Above Gold Zones", dated 7 February 2022
· "Wudinna Project Update - Re-Analysis Defines Large Rare Earth
Mineralisation Footprint Above Baggy Green and Clarke Gold Mineralisation",
dated 4 May 2022
· "Wudinna Project Update - Aircore Drilling Yields Exceptional Gold
and Rare Earth Results at Clarke" dated 16 August 2022
· "Wudinna Project Update - Additional High-Grade Rare Earths Defined
Across Regional Targets" dated 12 September 2022
· "Wudinna Project Update - Exceptional Rare Earth Scale Potential at
Thompson Prospect Increases REE Footprint from 4 km(2) to 22.5 km(2)" dated
26 September 2022
Definitions
REE - Rare Earth Elements
REO - Rare Earth Oxides
MREO - Magnet Rare Earth Oxides (dysprosium + terbium + praseodymium,
neodymium)
TREO - Total Rare Earth Oxides plus yttrium
TREO-Ce - Total Rare Earth Oxides plus yttrium and minus cerium
Further Information Regarding the REE MRE
Location and Land Tenure
The Wudinna Project is located on the northern Eyre Peninsula, within South
Australia, a tier 1 mining jurisdiction. The defined REE MRE occurs within
EL6131 (Corrobinnie) and lies within the Pinkawillinie Conservation Park (dual
proclamation land). The tenement is held by Peninsula Resources, a subsidiary
of Andromeda Metals. Cobra has the right to earn up to 75% in the project
through the Wudinna Heads of Agreement. In October 2021, the Company announced
it had achieved its 65% earn-in obligation.
Figure 2: Locality plan
Geology and Nature of the REE Mineralisation
The gold and REE deposits at the Wudinna Project are considered to be related
to the structurally controlled basement weathering of epidote-pyrite
alteration related to the 1590 Ma Hiltaba/GRV tectonothermal event of the
Gawler Craton. Gold and REE 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.
The REE mineralisation is regionally extensive in weathered (saprolite and
saprock) zones developed on basement rocks. The nature of controlling
structures that act as conduits for gold mineralisation are also thought to
act as catalysts for the secondary processes that promote weathering and
subsequent mobilisation of REEs to the saprolite and saprock.
The following simplified model is proposed for ionic REEs and the Clarke and
Baggy Green prospects:
· Gold and sulphide mineralisation is directly associated with
Hiltaba Suite volcanics (~1590-1575 Ma)
· WNW redial shears, under north-south compression (craton
emplacement) act as dilatational conduits through Kimbian and Sleaford age
granitoids
· Hiltaba suite mafics are enriched in light REEs
· Gold and sulphide mineralisation forms along sheeted granitoid
"dome" joints, bound within shear zones
· Sericite and epidote alteration halos form peripheral to gold
mineralisation
· Epidote alteration is enriched in REEs providing an enriched
source
· Supergene enrichment of gold occurs at the base of oxidation
where the weathering of primary sulphides generates acidic conditions
· Primary REE phases are weathered to secondary REE phases through
prolonged weathering.
· Acidic conditions generated by the weathering of sulphides
re-mobilises REEs
· Near redox boundaries (pH 6-7) a greater component of REE is
absorbed to clay particles.
· Colloidal phases occur as conditions become alkaline
Figure 3: Proposed geological model for gold and REE mineralisation at the
Clarke and Baggy Green prospects
X-Ray Diffraction analysis performed by the Commonwealth Scientific and
Industrial Research Organisation supports that a component of REE bursary is
adsorbed to the primary clay particles, being kaolin and montmorillonite, in
similar fashion to the highly desirable Ion Adsorbed Clay hosted deposits of
southern China.
SEM analyses performed by the University of South Australia determined that:
· Primary REE mineral phases in basement, hard rock lithologies are
zircon, titanite, apatite, andradite, epidote
· Secondary REE mineral phases within the lower saprock (weakly to
moderately weathered basement) are monazite, basanite, allanite, rutile
Figures 4-6: SEM imagery of samples from 27, 47 and 117m downhole of CBRC0042
· REE enrichment in source rock is associated with Hiltaba
intrusive alteration, the primary gold mineralising event
· Elevated phosphate is identified at the base of saprolite,
however the peak is not associated with elevated REE grades (Figure 7)
Figure 7: REE grades downhole of CBRC0042 intersected 8.2m at 561 ppm TREO
from 38.1m below surface, and 19m at 0.79 g/t gold from 83m, including 5m at
2.62 g/t gold from 95m
· Definitive change in REE bearing mineral phases between basement
and saprolite, demonstrated by the calculated mass abundance of respective REE
mineral phases
· Rare Earth grade peaks in the upper saprolite occur where
secondary REE phases are low, supporting clay adsorption
The identified changes in mineral phase from hard rock to lower saprock and
the occurrence of grade peaks within the weathered saprolite with very low
identifiable rare earth mineral phases is supportive of a component of the REE
bursary being adsorbed to clay particles and is analogous to the ionic rare
earth deposits of Southern China.
Figure 8: CBRC0042 downhole REO grades, sample pH and the SEM calculated
primary and secondary rare earth bearing mineral phases
Drilling Techniques
The Mineral Resource Estimate is based upon the drill results or re-analysis
of 204 drillholes (14,509m) that consist of aircore, rotary hammer, reverse
circulation (RC) and a single diamond drillhole. 36 RC and 34 aircore holes
have been drilled by Cobra since 2019. All rare earth results incorporated
within the Mineral Resource Estimate were announced during 2022.
The drillhole spacing within the Mineral Resource area is generally 200m by
200m, however, areas of tighter drilling and sampling occur proximal to gold
mineralisation where drill density is up to 25m by 100m.
The drilling and subsequent estimation which informs the Thompson Exploration
Target of 81-223 Mt is based on drill traverses of 1 km spacing and drillhole
line spacings of 200m. The potential quantity and grade of the Exploration
Target is conceptual in nature as there has been insufficient exploration to
estimate a Mineral Resource, however, the framework of drilling at Thompson
provides the potential to yield a future resource.
Sampling and Sub-sampling Techniques
Downhole sample composites vary over the Mineral Resource, with historic
drilling and subsequent re-analysis being performed on pulp samples from 1, 2,
4 and 6m down-hole intervals. Samples from Cobra's drilling have produced 1m
composites from RC drilling and 2m from aircore drilling. Owing to the
variable nature of REE mineralisation through the saprolite, greater composite
lengths are expected to understate grade.
Sample Analysis Methods
Samples were submitted to Genalysis Intertek Laboratories, Adelaide for
preparation and analysis. Multi element geochemistry were digested by four
acid ICP-MS and analysed for Ag, Ce, Cu, Dy, Er, Eu, Gd, Ho, La, Lu, Na, Nd,
Pr, Sc, Sm, Tb, Th, Tm, U, Y and Yb.
Mineral Resource Estimation and Classification
The Mineral Resource has been estimated by independent consultants to the
Company: Snowden Optiro.
The resource model for the REE mineralisation at Clarke and Baggy Green was
constructed using a parent block size of 25 mE by 40 mN on 1 m benches and the
parent blocks were allowed to sub-cell down to 5 mE by 10 mN by 0.5 mRL to
more accurately represent the geometry and volume of the saprolite and saprock
domains. Categorical indicator kriging (CIK) at the sub-cell resolution was
used to define REE mineralised (>100 ppm CeO(2)) blocks. The REE block
grades were estimated using ordinary kriging. All REE (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) and Y(2)O(3)) were
estimated independently.
The Mineral Resources have been classified as Inferred on the basis of
confidence in geological and grade continuity and taking into account data
quality, data density and confidence in the grade estimation, using the
modelled grade continuity. In places the drillhole density is sufficient to
support a higher Mineral Resource classification and scope exists to review
the current Mineral Resource classification if positive results are obtained
from additional metallurgical studies that support economic viability.
Figure 9: Extent of Mineral Resource Estimate, proximal to gold mineralisation
Figure 10: Cross section 6364870mN demonstrating the REE MRE, overlying
intersected gold mineralisation
Density
Density was measured for 19 saprolite samples from diamond drilling at the
Baggy Green and Barns gold Prospects that exhibit a range of densities between
1.2 t/m(3) and 2.01 t/m(3). The average density of 1.6 t/m(3) was applied for
tonnage estimation.
Cut-off Grade
The Mineral Resource has been reported above a cut-off grade of TREO-Ce of 320
ppm and assumes extraction by open pit mining. The cut-off grade was
selected based on the evaluation of other advanced clay hosted rare earth
Mineral Resources and the consideration that future economic analysis of the
cut-off grade is likely to incorporate parameters that support extraction of
the underlying gold mineralisation.
Metallurgy
· Preliminary metallurgical test work focusing on extraction techniques
adopted to ionic phase mineralisation using H(2)SO(4) as a lixiviant, and
performed by Australia's Nuclear Science and Technology Organisation, yielded
recoveries of up to 34% Total Rare Earth Element ("TREE") from samples across
two holes at Clarke
· Preliminary metallurgical testwork has provided positive indications
that REE bursary is bound to clay particles. The identification of a technique
or techniques to optimally recover rare earth metals from the saprolite
mineralisation is ongoing with further desorption and leach testing underway
· pH testing of drill samples demonstrates variable conditions across
all Prospects, saprolite horizons, and types of clays that are associated with
high REE adsorption capacity
· The nature of the bonds which adsorb the REEs within enclosing clay
appear dependent upon the local chemical environment:
o Where local pH is greater than optimal (moderately alkaline), colloidal
bonding is more abundant and a positive cerium anomaly is generally present
o Where local pH is in an optimal range, ionic bonding appears favoured, the
valuable MREO mineral suite is enhanced (pH 5-6.8), and REE baskets generate
negative cerium anomalies
o Where local pH is lower than optimal (acidic), REEs appear to have
remained mobile and enhanced grades are not retained within the saprolite
zone
Figure 11: pH analysis of 86 downhole composites at Clarke demonstrating grade
peaks at acidity and alkaline conditions that support ionic adsorption of REE
to clay particles
· pH testwork completed to date provides an encouragement that it can
be utilised as a process to identify metallurgical upside
· REE grade is considerably higher at pH conditions 6-7 and 9-10.
Should further metallurgical testing support a higher component of ionic
adsorption, then saprolite acidity will be a key identifier for determining
higher grades and zones amenable to lower processing costs
Figure 12: TREO breakdown of the Clarke dataset evaluating drillhole grades at
a cut-off of 350 ppm TREO compared to a pH range of 6-7
REE Mineral Resource update
Appendix 1: JORC Code, 2012 Edition - Table 1
The table below summaries the assessment and reporting criteria used for the
Clarke and Baggy Green REE Mineral Resource estimate and reflects the
guidelines in Table 1 of The Australasian Code for the Reporting of
Exploration Results, Mineral Resources and Ore Reserves (the JORC Code, 2012).
Section 1 Sampling Techniques and Data
Criteria JORC Code explanation Commentary
Sampling techniques · Nature and quality of sampling (eg cut channels, random chips, or Pre 2021
specific specialised industry standard measurement tools appropriate to the
minerals under investigation, such as down hole gamma sondes, or handheld XRF · Historic RC and RAB drilling methods have been employed at Clarke
instruments, etc). These examples should not be taken as limiting the broad and Baggy Green Prospects since 2000.
meaning of sampling.
· Pulp samples from pre-Cobra Resources' drilling were collected
· Include reference to measures taken to ensure sample representivity with intervals of 1-6 m. Samples were riffle split if dry or sub
and the appropriate calibration of any measurement tools or systems used. split using a trowel if wet.
· Aspects of the determination of mineralisation that are Material to · Pulp samples were obtained from Challenger geological services
the Public Report. using a combination of logging and geochemical selection criteria. Samples
pulled from storage were re-pulverised at the laboratory prior to further
· In cases where 'industry standard' work has been done this would be analysis.
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 2021 - onward
assay'). In other cases more explanation may be required, such as where there
is coarse gold that has inherent sampling problems. Unusual commodities or · Sampling during Cobra Resources 2022 aircore ("AC") drilling
mineralisation types (eg submarine nodules) may warrant disclosure of detailed programme at all Prospects were obtained through AC drilling methods.
information.
· 2 m samples were collected in 20l buckets via a rig mounted
cyclone. An aluminum scoop was used to collect a 2-4 kg sub sample from each
bucket. Samples were taken from the point of collar, but only samples from the
commencement of saprolite were selected for analysis.
· Samples submitted to the Genalysis Intertek Laboratories,
Adelaide and pulverised to produce the 25g fire assay charge and 4 acid digest
sample.
· A summary of previous RC drilling at the Wudinna Project is
outlined in the Cobra Resources' RNS number 7923A from 7 February 2022.
Drilling techniques · Drill type (eg core, reverse circulation, open-hole hammer, rotary Pre 2021
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, · Drill methods include AC, RH and RAB in unconsolidated regolith
whether core is oriented and if so, by what method, etc). and aircore hammer in hard rock. Some shallow RC holes have been drilled in
place of AC and RAB, a single diamond drillhole has been incorporated in the
estimate.
2021- onward
· 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.
Drill sample recovery · Method of recording and assessing core and chip sample recoveries and · Sample recovery was generally good with water being intersected
results assessed. in less than 10% of the drilled holes. All samples were recorded for sample
type, quality and contamination potential and entered within a sample log.
· Measures taken to maximise sample recovery and ensure representative
nature of the samples. · In general, sample recoveries were good with 20-25 kg for each 2
m interval being recovered.
· Whether a relationship exists between sample recovery and grade and
whether sample bias may have occurred due to preferential loss/gain of · No relationships between sample recovery and grade have been
fine/coarse material. 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 with water being
intersected in 10% of the drilled holes. 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.
Logging · Whether core and chip samples have been geologically and · All drill samples were logged by an experienced geologist at the
geotechnically logged to a level of detail to support appropriate Mineral time of drilling. Lithology, colour, weathering and moisture were documented.
Resource estimation, mining studies and metallurgical studies.
· Logging is generally qualitative in nature.
· Whether logging is qualitative or quantitative in nature. Core (or
costean, channel, etc) photography. · All drill metres have been geologically logged on sample
intervals (1-2 m).
· The total length and percentage of the relevant intersections logged.
Sub-sampling techniques and sample preparation · If core, whether cut or sawn and whether quarter, half or all core Pre-2021
taken.
· Samples from AC, RAB and "bedrock" RC holes have been collected
· If non-core, whether riffled, tube sampled, rotary split, etc and initially as 6 m composites followed by 1 m re-splits. Many of the 1 m
whether sampled wet or dry. re-splits have been collected by riffle splitting.
· For all sample types, the nature, quality and appropriateness of the · RC samples have been collected by riffle splitting if dry, or by
sample preparation technique. trowel if wet
· Quality control procedures adopted for all sub-sampling stages to · Pulverised samples have been routinely checked for size after
maximise representivity of samples. pulverising
· Measures taken to ensure that the sampling is representative of the · Pulp samples were re- pulverised after storage to re-homogenise
in situ material collected, including for instance results for field samples prior to analysis.
duplicate/second-half sampling.
2021-onward
· Whether sample sizes are appropriate to the grain size of the
material being sampled. · The use of an aluminum scoop to collect the required 2-4 kg of
sub-sample from each 2 m AC sample length controlled the sample volume
submitted to the laboratory.
· Additional sub-sampling was performed through the preparation and
processing of samples according to the Intertek Genalysis internal protocols.
· Duplicate AC samples were collected from the sample buckets using
an aluminium scoop at a 1 in 50 sample frequency.
· Sample sizes were appropriate for the material being sampled.
· Assessment of duplicate results indicated this sub-sample method
provided good repeatability for rare earth elements.
· 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 20
samples. These samples showed good repeatability for REE.
Quality of assay data and laboratory tests · The nature, quality and appropriateness of the assaying and · Samples were submitted to Genalysis Intertek Laboratories,
laboratory procedures used and whether the technique is considered partial or Adelaide for preparation and analysis.
total.
· Multi element geochemistry were digested by four acid ICP-MS and
· For geophysical tools, spectrometers, handheld XRF instruments, etc, analysed for Ag, Ce, Cu, Dy, Er, Eu, Gd, Ho, La, Lu, Na, Nd, Pr, Sc, Sm, Tb,
the parameters used in determining the analysis including instrument make and Th, Tm, U, Y and Yb.
model, reading times, calibrations factors applied and their derivation, etc.
· Field gold blanks and rare earth standards were submitted at a
· Nature of quality control procedures adopted (eg standards, blanks, frequency of 1 in 50 samples.
duplicates, external laboratory checks) and whether acceptable levels of
accuracy (ie lack of bias) and precision have been established. · Field duplicate samples were submitted at a frequency of 1 in 50
samples
· Reported assays are to acceptable levels of accuracy and
precision.
· Internal laboratory blanks, standards and repeats for rare earths
indicated acceptable assay accuracy.
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.
· Significant intercepts have been prepared by Mr Rupert Verco and
reviewed by Mr Robert Blythman.
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 Google Pixel 6
mobile phone utilising the Avenza Map app. Collar points recorded with a
horizontal accuracy within 5 m.
· 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.
· All surveys are corrected to MGA 94 Zone 53 within the MX Deposit
database.
· The quality and accuracy of the topographic control is considered
sufficient for the Mineral Resource estimation and classification applied.
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
· Drillhole spacing does not introduce any sample bias.
· The data spacing and distribution is sufficient to establish the
degree of geological and grade continuity appropriate for interpretation of
the REE mineralised horizon and the classification applied.
Orientation of data in relation to geological structure · Whether the orientation of sampling achieves unbiased sampling of · The REE mineralisation is expected to be controlled by vertical
possible structures and the extent to which this is known, considering the weathering profiles.
deposit type.
· Vertical drill holes are expected to be perpendicular to rare earth
· If the relationship between the drilling orientation and the mineralisation.
orientation of key mineralised structures is considered to have introduced a
sampling bias, this should be assessed and reported if material. · It is not expected that the angled RC holes have introduced any
bias to the rare earth mineralisation interpretation.
· Drilling results are presented as true width.
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.
· 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 Laboratories Adelaide are a NATA (National
Association of Testing Authorities) accredited laboratory, recognition of
their analytical competence.
Appendix 2: 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 · This MRE is located within 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.
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 REDOX chemistry may
act as a catalyst for Ionic and Colloidal adsorption.
· REE mineral phase changes with varying saprolite acidity and REE
abundances support that a component of REE bursary is ionically adsorbed to
clays.
Drillhole Information · A summary of all information material to the understanding of the · Exploration results are not being reported as part of the Mineral
exploration results including a tabulation of the following information for Resource area.
all Material drill holes:
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 · Rare earth element analyses were originally reported in elemental
should be shown in detail. form and have been converted to relevant oxide concentrations in line with
industry standards. Conversion factors tabulated below:
· The assumptions used for any reporting of metal equivalent values
Element Oxide Factor
should be clearly stated. 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)
· 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
Relationship between mineralisation widths and intercept lengths · These relationships are particularly important in the reporting of · Preliminary results support unbiased testing of mineralised
Exploration Results. structures.
· If the geometry of the mineralisation with respect to the drill hole · Previous holes have been drilled in several orientations due to the
angle is known, its nature should be reported. unknown nature of mineralisation.
· If it is not known and only the down hole lengths are reported, there · Most intercepts are vertical and reflect true width intercepts.
should be a clear statement to this effect (eg 'down hole length, true width
not known'). · Exploration results are not being reported for the Mineral Resource
area.
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 and detailed gold intersections.
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 · Infill and extensional drilling aimed at growing the Mineral Resource
extensions or depth extensions or large-scale step-out drilling). and converting Inferred Resources to Indicated Resources is planned.
· 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 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)
· 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
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').
· Preliminary results support unbiased testing of mineralised
structures.
· Previous holes have been drilled in several orientations due to the
unknown nature of mineralisation.
· Most intercepts 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 and detailed gold intersections.
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.
· Infill and extensional drilling aimed at growing the Mineral Resource
and converting Inferred Resources to Indicated Resources is planned.
Appendix 3: Section 3 Estimation and Reporting of Mineral Resources
Criteria JORC Code explanation Commentary
Database integrity · Measures taken to ensure that data has not been corrupted by, for example, · The drillhole database is managed in-house by Cobra Resources using
transcription or keying errors, between its initial collection and its use for the Company's Seequent MXDeposit database.
Mineral Resource estimation purposes.
· It has been validated by MXDeposit specialists and Cobra Resources.
· Data validation procedures used.
· Data has been imported from current and historical data files.
· Source data for historical drilling has been verified as being
drilled by Andromeda Metals and imported directly from their Datashed
database.
· Additional data validation, by Snowden Optiro, included checking for
out of range assay data and overlapping or missing intervals.
Site visits · Comment on any site visits undertaken by the Competent Person and the · Mrs C Standing (Snowden Optiro, acting as Competent Person) has not
outcome of those visits. visited the Wudinna Gold Project.
Geological interpretation · Confidence in (or conversely, the uncertainty of) the geological · REE mineralisation at Clarke and Baggy Green is within saprolite and
interpretation of the mineral deposit. saprock horizons. There is reasonable confidence in the geological
interpretation of these horizons within the Mineral Resource area.
· Nature of the data used and of any assumptions made.
· The saprolite and saprock horizons were interpreted from geological
· The effect, if any, of alternative interpretations on Mineral Resource logging data using Leapfrog Geo software.
estimation.
· The use of geology in guiding and controlling Mineral Resource estimation.
· The factors affecting continuity both of grade and geology.
Dimensions · The extent and variability of the Mineral Resource expressed as length · The area used to constrain the Mineral Resource (that is within 50 m
(along strike or otherwise), plan width, and depth below surface to the upper of the drilling) extends for 1.5 km east-west by 3 km north-south. The
and lower limits of the Mineral Resource. mineralisation is contained within a horizon of weathered saprolite and
saprock that has a thickness ranging from 1 to 69 m and an average thickness
of 36 m. The top of this horizon extends from surface to 24 m.
Estimation and modelling techniques · The nature and appropriateness of the estimation technique(s) applied and · Data analysis and estimation was undertaken using Snowden Supervisor
key assumptions, including treatment of extreme grade values, domaining, and Datamine software.
interpolation parameters and maximum distance of extrapolation from data
points. If a computer assisted estimation method was chosen include a · REE block grades were estimated using ordinary kriging (OK). Snowden
description of computer software and parameters used. Optiro considers OK to be an appropriate estimation technique for this type of
mineralisation.
· The drillhole spacing within the Mineral Resource area is generally
200 m by 200 m, however, areas of tighter drilling and sampling occur proximal
to gold mineralisation where drill density is up to 25 m by 100 m.
· A maximum extrapolation distance of 50 m was applied around the
drilled area.
· Almost 61% of the La and Ce assay data within domains is from samples
of ≤1 m intervals, 24% is from intervals of >1 m to 2 m and 15% is from
intervals of >2 to 6 m. The data was composited to 1 m intervals for
statistical analysis and grade estimation.
· Statistical analysis indicated that outlier grades are not present
and top-cutting (grade-capping) was not applied.
· Variogram analysis was undertaken to determine the kriging estimation
parameters used for OK estimation of each REE.
· Variogram analysis was undertaken for each REE within the saprolite
and saprock. Within the mineralised area of the saprolite maximum continuity
ranges are 95 to 420 m E-W and 54 m to 166 m N-S. Within the saprock maximum
continuity ranges are 100 to 280 m NE-SW and 295 m to 450 m NW-SE.
· Kriging neighbourhood analysis was performed to determine the block
size, sample numbers and discretisation levels.
· Three estimation passes were used in block grade estimation; the
first search was based upon the La(2)O(3) variogram ranges; the second search
was two times the initial search and the third search was up to five times the
initial search. The second and third searches had reduced sample numbers
required for estimation. Almost 55% of the total block grades were estimated
in the first search pass, 34% within the second search pass and the remaining
11% estimated in the third search pass.
· Description of how the geological interpretation was used to control the · Geological interpretations of the top of basement, saprock and
resource estimates. saprolite horizons and the transported cover sediments were completed using
Leapfrog Geo software. 3D interpretations of the saprock and saprolite were
used to constrain the Mineral Resource estimate.
· Categorical indicator kriging (CIK) at the sub-cell resolution was
used to define REE mineralised (>100 ppm CeO(2)) blocks within the
saprolite horizon.
· The mineralised domains are considered geologically robust in the
context of the resource classification applied to the estimate.
· The availability of check estimates, previous estimates and/or mine · Mineral Resources have not previously been reported for this deposit
production records and whether the Mineral Resource estimate takes appropriate area and no production has occurred.
account of such data.
· The assumptions made regarding recovery of by-products. · No assumptions have been applied for the recovery of by-products.
· Estimation of deleterious elements or other non-grade variables of economic · Deleterious elements were not considered for the Mineral Resource
significance (e.g. sulphur for acid mine drainage characterisation). estimate.
· In the case of block model interpolation, the block size in relation to the · Grade estimation was into parent blocks of 25 mE by 40 mN by 1mRL.
average sample spacing and the search employed.
· Block dimensions were selected from kriging neighbourhood analysis
and reflect the variability of the deposit as defined by the current drill
spacing.
· Sub-cells to a minimum dimension of 5 mE by 10 mN by 0.5 mRL were
used to represent volume.
· The drillhole spacing within the Mineral Resource area is generally
200 m by 200 m, however, areas of tighter drilling and sampling occur proximal
to gold mineralisation where drill density is up to 25 m by 100 m.
· Search ellipse dimensions were selected from variogram analysis of
L(2)O(3).
· Any assumptions behind modelling of selective mining units. · Selective mining units were not modelled.
· Any assumptions about correlation between variables. · The REEs have moderate to high correlation coefficients (0.68 to
0.99).
· All REEs (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) and Y(2)O(3)) were estimated independently.
· The process of validation, the checking process used, the comparison of · The estimated block model grades were:
model data to drillhole data, and use of reconciliation data if available.
o visually validated against the input drillhole data
o comparisons were carried out against the declustered drillhole data and by
northing, easting and elevation slices.
o global statistical comparisons were carried out between the mean input
sample grade with the estimated block grade for each domain (saprock and the
mineralised and low grade REE domains in the saprolite).
· No production has taken place and thus no reconciliation data is
available.
Cut-off parameters · The basis of the adopted cut-off grade(s) or quality parameters applied. · The Mineral Resource has been reported above a cut-off grade of
TREO-Ce of 320 ppm and assumes extraction by open pit mining.
· This cut-off grade was selected based on the evaluation of other
advanced clay hosted rare earth Mineral Resources and the consideration that
future economic analysis of the cut-off grade is likely to incorporate
parameters that support extraction of the underlying gold mineralisation.
Mining factors or assumptions · Assumptions made regarding possible mining methods, minimum mining · Planned extraction is by open pit mining.
dimensions and internal (or, if applicable, external) mining dilution. It is
always necessary as part of the process of determining reasonable prospects · Mining factors such as dilution and ore loss have not been applied.
for eventual economic extraction to consider potential mining methods, but the
assumptions made regarding mining methods and parameters when estimating
Mineral Resources may not always be rigorous.
Metallurgical factors or assumptions · The basis for assumptions or predictions regarding metallurgical · Preliminary work performed by Metallurgical Test Work performed by
amenability. It is always necessary as part of the process of determining the Australian Nuclear Science and Technology Organisation (ANSTO)
reasonable prospects for eventual economic extraction to consider potential demonstrated recovery potential via desorption/leaching conditions where:
metallurgical methods, but the assumptions regarding metallurgical treatment
processes and parameters made when reporting Mineral Resources may not always · At pH4, 0.5M (NH4)2SO4 as lixiviant REE recoveries were generally
be rigorous. below 10%
· At pH1, (NH4)2SO4 as lixiviant recoveries increased with leach
period. At 6 hours recoveries up to 34.7% were achieved.
· Subsequent mineralogy and acidity testing has identified zones that
are likely to have a higher component of ionic adsorption and are therefore
likely to lead to higher recoveries.
· The samples submitted were from gold bearing holes, the pH conditions
do not fit the criteria for REDOX controlled ion adsorption.
· Further metallurgy testing is underway to validate these findings.
· Metallurgy optimisation tests are being carried out on bulk samples
by the University of South Australia.
Environmental factors or assumptions · Assumptions made regarding possible waste and process residue disposal · No assumptions have been made regarding waste and process residue.
options. It is always necessary as part of the process of determining
reasonable prospects for eventual economic extraction to consider the
potential environmental impacts of the mining and processing operation.
Bulk density · Whether assumed or determined. If assumed, the basis for the assumptions. · Average values have been calculated from the dataset.
If determined, the method used, whether wet or dry, the frequency of the
measurements, the nature, size and representativeness of the samples. · Bulk density measurements were calculated by water displacement
method. Samples from the saprolite zone were wrapped in cling film before
· The bulk density for bulk material must have been measured by methods that testing.
adequately account for void spaces (vugs, porosity, etc), moisture and
differences between rock and alteration zones within the deposit. · Density was measured for 19 samples from the saprolite zone. Values
range from 1.26 t/m(3) to 2.1 t/m(3), with an average 1.6 t/m(3). The average
· Discuss assumptions for bulk density estimates used in the evaluation of 1.6 t/m(3) was used for tonnage estimation.
process of the different materials.
Classification · The basis for the classification of the Mineral Resources into varying · The Mineral Resources have been classified as Inferred on the basis
confidence categories. of confidence in geological and grade continuity and taking into account data
quality, data density and confidence in the grade estimation, using the
· Whether appropriate account has been taken of all relevant factors (i.e. modelled grade continuity.
relative confidence in tonnage/grade estimations, reliability of input data,
confidence in continuity of geology and metal values, quality, quantity and · The assigned classification of Inferred reflects the Competent
distribution of the data). Person's assessment of the accuracy and confidence levels in the Mineral
Resource estimate.
· Whether the result appropriately reflects the Competent Person's view of
the deposit.
Audits or reviews · The results of any audits or reviews of Mineral Resource estimates. · The Mineral Resource has been reviewed internally as part of normal
validation processes by Snowden Optiro.
· No external audit or review of the current Mineral Resource has been
conducted.
Discussion of relative accuracy/ confidence · Where appropriate a statement of the relative accuracy and confidence level · The assigned classification of Inferred reflects the Competent
in the Mineral Resource estimate using an approach or procedure deemed Person's assessment of the accuracy and confidence levels in the Mineral
appropriate by the Competent Person. Resource estimate.
· The statement should specify whether it relates to global or local · The statement relates to global estimates of tonnes and grade.
estimates, and, if local, state the relevant tonnages, which should be
relevant to technical and economic evaluation. · No production data exists for the Wudinna Project gold or REE
deposits.
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. END UPDUWVRRORUARURRecent news on Cobra Resources
See all newsREG - Cobra Resources PLC - Final Results for the Year Ended 31 December 2024
AnnouncementREG - Cobra Resources PLC - Sonic Drilling Commences at Boland
AnnouncementREG - Cobra Resources PLC - Updates re Rare Earth & Gold Projects
AnnouncementRCS - Cobra Resources PLC - Response to China’s Rare Earths Export Controls
AnnouncementREG - Official List - Official List Notice
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