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JURISDICTION.
25 March 2024
Cobra Resources
plc
("Cobra"
or the "Company")
Drilling Results from Boland
Prospect
Assays confirm high grade
concentrations; modelled geology demonstrates massive scale; high
calculated permeability supports in situ recovery
Cobra
(LSE: COBR), an exploration
company focused on the Wudinna Project ("Wudinna") in South
Australia, is pleased to announce that preliminary results from
recent sonic core drilling at the Boland ionic rare earths ("REE")
prospect further demonstrate that the discovery could be a world
class source of magnet and heavy rare earths.
Cobra confirmed ionic REE
metallurgical recoveries at Boland in 2023 and recent sonic core
drilling has provided greater geological detail which confirms the
Company's thesis that grade concentrations are high, mineralisation
is amenable to low-cost extraction via in situ recovery ("ISR"),
and the discovery has exceptional province scale potential. Results
demonstrate:
·
High grade
concentrations across three zones of
mineralisation
·
High grades in
geological formations with high permeabilities amenable to
ISR
·
Modelled
mineralised units support exceptional scale
Rupert Verco, CEO of Cobra,
commented:
"These results are sensational! It is pleasing to see our
value proposition materialise, and these results, coupled with the
excellent metallurgical recoveries achieved last year, demonstrate
Boland is not only unique but world class.
The value of in situ recovery cannot be overestimated. It is
the preferred mining method from scale, cost and environmental
perspectives and we are now positioned to be industry leaders in
applying this form of mining long used for uranium to ionic rare
earth mineralisation.
Whilst the Brazilian ionic rare earth projects have captured
market interest, our results are comparable in grade, scale and
metallurgy and the Boland prospect's advantage is the unique
geology that makes it amenable to ISR. Our forward work programme
is designed to demonstrate the project's commercial advantage as we
continue to define scale, grade upside, and highlight the value of
ISR."
Highlights
·
High grade
concentrations across three zones of mineralisation:
results received from three holes intersect three zones of
mineralisation that yield length-weighted averages of:
o Zone 1:
3.1m at 1,007 ppm Total Rare Earth Oxides
("TREO"), where Nd2O3 +
Pr6O11 totals 212 ppm and
Dy2O3 + Tb2O3 totals
23.5 ppm (Magnet Rare Earth Oxides ("MREO") 23.4%, Heavy Rare Earth
Oxides ("HREO") 17%) from 15.6m
o Zone 2:
1.9m at 1,043 ppm TREO, where
Nd2O3 + Pr6O11 totals
205 ppm and Dy2O3 +
Tb2O3 totals 22 ppm (MREO 22%, HREO 18%) from
~20.5m
o Zone
3: 0.6m at 1,538 ppm TREO
where Nd2O3 +
Pr6O11 totals 305 ppm and
Dy2O3 + Tb2O3 totals 52
ppm (MREO 23%, HREO 28%) from ~26.6m
·
High grades with
high permeabilities: the highest
grade assay of 4,608 ppm TREO, where Nd2O3 +
Pr6O11 totals 934 ppm and Dy2O3
+ Tb2O3 totals 91 ppm (MREO 24%, HREO 27%), comes from
Zone 3, where:
o Particle size distribution analysis supports high calculated
permeabilities with 67.6% of the mineralised interval having a
particle size greater than 0.1mm (fine sand)
o Particle size distribution yields a high calculated
transmissivity of 135-275 m/day1 and is very supportive
of high ISR success
o The
highest ionic recoveries were yielded: 79% Tb, 67% Dy, 60% Nd and
47% Pr using a simple AMSUL wash at pH3
Further sizing analysis is underway
for Zones 1 and 2
·
Modelled
mineralised units support exceptional
scale: mineralised host units have
been modelled across the palaeochannel at Boland, where:
o The
geological formation hosting Zone 1 mineralisation is mapped across
~128,000,000m2
o The
geological formation hosting Zone 2 mineralisation is mapped across
~58,000,000m2
o The
geological formation hosting Zone 3 mineralisation is mapped across
~139,000,000m2
·
Modelling is based on the downhole geophysical
responses attributed to each mineralised zone in alignment with a
REPTEM survey flown in 2008 that defines the base of the Narlaby
Palaeochannel
·
Downhole geophysics from historical uranium
focused drilling has been digitised, interpreted and wireframes
developed
·
233 samples from 13 drillholes from south and
north of Boland are at the laboratory. These results will validate
and refine the model with the aim of supporting a near term maiden
mineral resource estimation
Next Steps:
·
Samples are being prepared for mineralogy studies
to understand the adsorption characteristics of REEs
·
Sieve sizes are being assayed to understand
distribution of REEs
·
A total of 233 historic pulp samples from the
greater Boland target area have been submitted for re-analysis to
validate the model of mineralised geological formations
·
A total of five holes were drilled, cased, and
screened with slotted PVC screens. Screens have been set at a depth
to coincide with Zone 3 mineralisation. These wells will enable
hydrology studies and support a future pilot study
·
Hydrology testing has commenced. Water quality and
water yield data will be compiled to define environmental baselines
and evaluate productivity potential
·
Select zones of core have been sent to Australia's
Nuclear Science and Technology Organisation ("ANSTO") to enable
column ISR testing. Results from these tests are anticipated to
support the amenability of mineralisation to be mined through
ISR
·
Pregnant solutions from ANSTO testwork will be
used by Watercycle Technologies to advance a flow sheet through
membrane desorption
·
Hydrology testing has commenced. Water quality and
water yield data will be compiled to define environmental baselines
and evaluate productivity potential
Sonic Drilling - Overview of Boland Strategy
Results are from a five drillhole
programme totalling 145m completed in February 2024. The programme
has successfully provided quality drill core that is enabling Cobra
to advance the ISR potential of the Boland ionic REE discovery.
Drilling was undertaken in a five-hole ISR wellfield configuration
at 25m spacings, where holes were cased and screened to support a
future "push-pull" pilot ISR study.
The wellfield was drilled proximal
to Aircore hole CBAC00163 that yielded the following
intersections:
·
Zone 1: 3m at 559 ppm TREO (24% MREO) from 18m
(playa clay)
·
Zone 2: 3m at 618 ppm TREO (22% MREO) from 21m
(playa clay)
·
Zone 3: 3m at 468 ppm TREO (21% MREO) from 27m
(basal clay)
·
Saprolite: 12m at 1,191 ppm TREO (27% MREO) from
36m
Cobra believed that, owing to the
geological and chemical conditions that promote ionic adsorption,
higher grades would be defined concentrated to lithologies with
high permeability and be amenable to ISR.
Sonic drilling has enabled
representative sampling. Narrow intervals relating to geology from
three holes were sampled and submitted for assay to evaluate
potential grade concentration. Length weighted average composites
from three sonic core holes assayed proximal to CBAC00163 validate
grade concentration, where:
o Zone 1:
3.1m at 1,007 ppm TREO (23.4% MREO) from 15.6m
represents a 180% increase in grade
o Zone 2:
1.9m at 1,043 ppm TREO (22% MREO) from ~20.5m
represents a 169% increase in grade
o Zone
3: 0.6m at 1,538 ppm TREO
(MREO 23%, HREO 28%) from ~26.6m represents a 329%
increase in grade
Increased grades confined to
permeable lithology is important from an ISR standpoint and bodes
well for future extraction success. Mineralised intervals from the
two holes not reported have been sent to ANSTO for bench scale
leach ISR testing. A summary of significant intersections is
tabulated below:
Table 1: Significant
intersections from sonic core holes
|
Mineralisation
zone
|
Hole ID
|
From (m)
|
To (m)
|
Int (m)
|
TREO
|
Pr6O11
|
Nd2O3
|
Tb2O3
|
Dy2O3
|
MREO %
|
HREO%
|
|
Zone
1
|
CBSC0001
|
15.6
|
19.2
|
3.7
|
1,025
|
49
|
172
|
4
|
22
|
24%
|
17%
|
|
Zone
2
|
CBSC0001
|
20.8
|
23.0
|
2.2
|
1,010
|
46
|
156
|
4
|
20
|
22%
|
18%
|
|
Zone
3
|
CBSC0001
|
27.0
|
27.7
|
0.7
|
2,118
|
90
|
321
|
10
|
59
|
23%
|
26%
|
|
Zone
1
|
CBSC0005
|
15.6
|
18.5
|
2.9
|
915
|
44
|
154
|
3
|
18
|
24%
|
16%
|
|
Zone
2
|
CBSC0005
|
19.5
|
21.4
|
1.9
|
1,226
|
56
|
192
|
4
|
19
|
22%
|
15%
|
|
Zone
3
|
CBSC0005
|
26.3
|
27.0
|
0.7
|
1,248
|
56
|
202
|
6
|
35
|
24%
|
27%
|
|
Zone
1
|
CBSC0004
|
15.7
|
18.5
|
2.8
|
1,082
|
48
|
167
|
4
|
20
|
22%
|
15%
|
|
Zone
2
|
CBSC0004
|
21.4
|
23.0
|
1.6
|
870
|
36
|
126
|
3
|
17
|
21%
|
17%
|
|
Zone
3
|
CBSC0004
|
26.3
|
26.8
|
0.5
|
1,130
|
45
|
179
|
7
|
38
|
24%
|
31%
|
Figure 1:
Aerial photograph of the Boland wellfield with
significant intersections
Table 2: Length weighted
averages of significant intersections
|
Mineralisation
zone
|
Int (m)
|
TREO
|
Pr6O11
|
Nd2O3
|
Tb2O3
|
Dy2O3
|
MREO %
|
HREO%
|
|
Zone
1
|
3.1
|
1,008
|
47
|
165
|
4
|
20
|
23%
|
16%
|
|
Zone
2
|
1.9
|
1,042
|
46
|
159
|
3.4
|
19
|
22%
|
17%
|
|
Zone
3
|
0.6
|
1,538
|
66
|
240
|
8
|
45
|
23%
|
28%
|
Association of Metallurgy to Mineralised
Lithology
Sonic core drilling has enabled the
Company to evaluate the nature of mineralisation and its potential
to be mined via ISR. Whilst sizing results, further assays, and
bench scale ISR column leach tests are outstanding, preliminary
observations are very positive and correlate well to diagnostic
metallurgical tests performed by ANSTO. Observations and average
recoveries by zone are summarised in table 3:
Table 3: 2023 averaged
metallurgical recoveries of magnet rare earths achieved in ANSTO
sighter testwork according to mineralised palaeochannel horizon and
the ranked ISR recovery potential
|
Min Zone
|
Lith
Summary
|
Acidity
(pH)
|
Pr
|
Nd
|
Tb
|
Dy
|
Acid consumption
(kg/t)
|
|
Zone
1
|
Upper
playa clay
|
4
|
16%
|
20%
|
31%
|
33%
|
15.9
|
|
3
|
22%
|
26%
|
31%
|
40%
|
22.3
|
|
Zone
2
|
Middle
playa clay and sand interbeds
|
4
|
22%
|
25%
|
37%
|
41%
|
17.3
|
|
3
|
36%
|
40%
|
52%
|
54%
|
28.8
|
|
Zone
3
|
Organic
rich - clayey sand
|
4
|
35%
|
45%
|
44%
|
49%
|
9.4
|
|
3
|
47%
|
60%
|
79%
|
67%
|
17.6
|
|
Upper
Saprolite
|
Weathered
granite
|
4
|
8%
|
11%
|
21%
|
16%
|
10.9
|
|
3
|
9%
|
13%
|
27%
|
25%
|
29.2
|
Downhole Geophysics and Implications for
Scalability
All sonic core holes were logged for
lithology and compared against downhole geophysical measurements.
Downhole geophysical responses can de directly attributed to the
geological formations that host mineralisation. In
particular:
·
Zone
1: mineralisation is confined
between two distinct gamma peaks at the margins of the mineralised
unit, where the lower peak relates to a narrow, coarse reduced sand
unit
·
Zone
2: mineralisation has an overall low
gamma response where small spikes associate with elevated REE
grades
·
Zone
3: mineralisation is associated with
a high geophysical response that is interpreted to be a product of
the high quantity of organics contained within the mineralised
sandy clay
Figure 2-4: Grade distribution
of rare earths down-hole and their association to palaeochannel
geology and associated downhole geophysics
|
Drillhole: CBSC0001
|
Drillhole: CBSC0004
|
|
|
|
|
Drillhole: CBSC0005
|
|
|
|
|
·
Downhole geophysics across all five sonic core
holes exhibit responses that can be attributed to mineralised
lithologies
·
The Boland prospect is located on EL5953 "Minipa"
where uranium explorers have previously undertaken exploration and
carried out downhole geophysics on numerous holes across the
tenement
·
Downhole geophysical data and historical logs have
been digitised and interpreted, enabling Cobra's technical team to
assess the extent of the mineralised zones across the tenement
area
·
Mineralised zones are most prominent on the
margins of the palaeosystem, which is interpreted to be a result of
their marine transgressional deposition and not the fluvial
depositional environment that is constrained in the central
portions of the palaeochannel
·
This supports significant scale potential as
sediments from marine transgression are interpreted to be more
extensive across the palaeosystem
·
The scale of the geological formations that host
mineralisation are mapped across ~155km2 on EL5953
alone. Recent reanalysis results demonstrate that these formations
host mineralisation across the Company's greater tenement holdings
which cover an additional 1,850km2 of
palaeosystems
·
Re-analysis of samples from drillholes highlighted
in Figure 5 are aimed to validate the modelled zones and confirm
estimated volumes
·
Collation and digitisation of downhole geophysical
data across Cobra's greater land tenure is ongoing and will inform
further re-analysis and future drilling
·
Follow-up Aircore drilling will be designed to
infill shortfalls in geological data, supporting a maiden mineral
resource estimate
Figure 5: 3D section
highlighting the modelled geological units that host REE
mineralisation (zones 1-3)
Figure
6: Plan view - highlighting the
regional scale of the mapped geological units that host Boland
ionic REE mineralisation and the holes that form stage 2 of the
Company's re-assay strategy
Particle Size Distribution
Samples from each mineralised zone
were taken and screened to evaluate:
·
The particle distribution of mineralised
lithologies
·
The distribution of grade to particle
size
·
The permeability of material and its amenability
to ISR
Samples were wet screened, and only the results
on a zone 3 sample are reported. Results are highly favourable for
ISR and indicate:
·
Zone 3 mineralisation has a high quantity of sand
with 67% of the sample mass screening above 0.1mm
·
Particle size distribution parameters have been
used to calculate the potential permeability using the
Kozeny-Carman equation1, where:
o Using the median particle size distribution yields a very high
permeability of 275 m/day
o Using the lower quartile of the particle distribution analysis
provides a moderate -high permeability of 135 m/day
Figure 7: Particle size
distribution of zone 3 (27-27.5m) from drillhole
CBSC0001
Figure 8: Cumulative
distribution of particle sizes by screen passing
Enquiries:
|
Cobra Resources plc
Rupert Verco (Australia)
Dan Maling (UK)
|
via Vigo
Consulting
+44 (0)20
7390 0234
|
|
SI
Capital Limited (Joint Broker)
Nick Emerson
Sam Lomanto
|
+44
(0)1483 413 500
|
|
Global Investment Strategy (Joint Broker)
James Sheehan
|
+44 (0)20
7048 9437
james.sheehan@gisukltd.com
|
|
Vigo
Consulting (Financial Public Relations)
Ben Simons
Kendall Hill
|
+44 (0)20
7390 0234
cobra@vigoconsulting.com
|
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 Gold and Rare Earth 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 1,832 km2, and other
nearby tenement rights totalling 2,941 km2,
contain highly desirable and ionic rare
earth mineralisation, amenable to low-cost, low impact in situ
recovery mining, and critical to global decarbonisation.
Additionally, Cobra holds a 213 km2 exploration tenement
in northern Tasmania which is also considered highly prospective
for ionic rare earth mineralisation.
Cobra's Wudinna tenements also
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 279,000 Oz gold JORC
Mineral Resource Estimate, and several iron oxide copper gold
(IOCG) targets.
Follow us on social media:
LinkedIn: https://www.linkedin.com/company/cobraresourcesplc
Twitter: https://twitter.com/Cobra_Resources
Subscribe to our news alert service:
https://cobraplc.com/news/
Appendix 1: JORC Code, 2012 Edition
- Table 1
Section 1 Sampling Techniques and Data
|
Criteria
|
JORC Code explanation
|
Commentary
|
|
Sampling
techniques
|
·
Nature and
quality of sampling (eg cut channels, random chips, or specific
specialised industry standard measurement tools appropriate to the
minerals under investigation, such as down hole gamma sondes, or
handheld XRF instruments, etc). These examples should not be taken
as limiting the broad meaning of sampling.
·
Include
reference to measures taken to ensure sample representivity and the
appropriate calibration of any measurement tools or systems
used.
·
Aspects of the
determination of mineralisation that are Material to the Public
Report.
·
In cases where
'industry standard' work has been done this would be relatively
simple (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 assay'). In other cases more explanation may be required, such
as where there is coarse gold that has inherent sampling problems.
Unusual commodities or mineralisation types (eg submarine nodules)
may warrant disclosure of detailed information.
|
2023
RC
· Samples were collected via a Metzke cone splitter mounted to
the cyclone. 1m samples were managed through chute and butterfly
valve to produce a 2-4 kg sample. Samples were taken from the point
of collar, but only samples from the commencement of saprolite were
selected for analysis.
· Samples submitted to Bureau Veritas Laboratories, Adelaide,
and pulverised to produce the 50 g fire assay charge and 4 acid
digest sample.
AC
· A
combination of 2m and 3 m samples were collected in green bags via
a rig mounted cyclone. An PVC spear was used to collect a 2-4 kg
sub 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.
· Samples have been submitted to Bureau Veritas for 4 acid
digest ICP analysis.
|
|
Drilling
techniques
|
·
Drill type (eg
core, reverse circulation, open-hole hammer, rotary 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, whether core is oriented and if so, by what method,
etc).
|
2023
· Drilling completed by Bullion Drilling Pty Ltd using 5 ¾"
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 results
assessed.
·
Measures taken
to maximise sample recovery and ensure representative nature of the
samples.
·
Whether a
relationship exists between sample recovery and grade and whether
sample bias may have occurred due to preferential loss/gain of
fine/coarse material.
|
Aircore & RC
· Sample
recovery was generally good. All samples were recorded for sample
type, quality and contamination potential and entered within a
sample log.
· In
general, sample recoveries were good with 10 kg for each 1 m
interval being recovered from AC drilling.
· 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 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 costean,
channel, etc) photography.
·
The total length
and percentage of the relevant intersections
logged.
|
Aircore & RC
· All
drill samples were logged by an experienced geologist at the time
of drilling. Lithology, colour, weathering and moisture were
documented.
· 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
taken.
·
If non-core,
whether riffled, tube sampled, rotary split, etc and whether
sampled wet or dry.
·
For all sample
types, the nature, quality and appropriateness of the sample
preparation technique.
·
Quality control
procedures adopted for all sub-sampling stages to maximise
representivity of samples.
·
Measures taken
to ensure that the sampling is representative of the in situ
material collected, including for instance results for field
duplicate/second-half sampling.
·
Whether sample
sizes are appropriate to the grain size of the material being
sampled.
|
2021-onward
· The
use of an aluminum scoop or PVC spear to collect the required 2-4
kg of sub-sample from each 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 lab internal
protocols.
· Duplicate AC samples were collected from the green bags using
an aluminium scoop or PVC spear at a 1 in 25 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 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 laboratory
procedures used and whether the technique is considered partial or
total.
·
For geophysical
tools, spectrometers, handheld XRF instruments, etc, the parameters
used in determining the analysis including instrument make and
model, reading times, calibrations factors applied and their
derivation, etc.
·
Nature of
quality control procedures adopted (eg standards, blanks,
duplicates, external laboratory checks) and whether acceptable
levels of accuracy (ie lack of bias) and precision have been
established.
|
· Samples were submitted to Bureau Veritas 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, Mg, Na, Nd, P, Pr, Sc,
Sm, Tb, Th, Tm, U, Y and Yb.
· For
the sonic samples Ag was removed from the analytical suite and V
was included
· Field
gold blanks and rare earth standards were submitted at a frequency
of 1 in 25 samples.
· Field
duplicate samples were submitted at a frequency of 1 in 25
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 or alternative
company personnel.
·
The use of
twinned holes.
·
Documentation of
primary data, data entry procedures, data verification, data
storage (physical and electronic) protocols.
·
Discuss any
adjustment to assay data.
|
· Sampling data was recorded in field books, checked upon
digitising and transferred to database.
· Geological logging was undertaken digitally via the MX Deposit
logging interface and synchronised to the database at least daily
during the drill programme.
· Compositing of assays was undertaken and reviewed by Cobra
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 and down-hole
surveys), trenches, mine workings and other locations used in
Mineral Resource estimation.
·
Specification of
the grid system used.
·
Quality and
adequacy of topographic control.
|
Pre 2021
· Collar
locations were pegged using DGPS to an accuracy of +/-0.5
m.
· Downhole surveys have been completed for deeper RC and diamond
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.
·
Whether the data
spacing and distribution is sufficient to establish the degree of
geological and grade continuity appropriate for the Mineral
Resource and Ore Reserve estimation procedure(s) and
classifications applied.
·
Whether sample
compositing has been applied.
|
·
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.
·
Additional scouting holes were drilled
opportunistically on existing tracks at spacings 25-150 m from
previous drillholes.
·
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 possible
structures and the extent to which this is known, considering the
deposit type.
·
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.
|
·
RC drillholes have been drilled between -60 and
-75 degrees at orientations interpreted to appropriately intersect
gold mineralisation
·
Aircore and Sonic drill holes are
vertical.
|
|
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 and BV Laboratories Adelaide
are 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 agreements or
material issues with third parties such as joint ventures,
partnerships, overriding royalties, native title interests,
historical sites, wilderness or national park and environmental
settings.
·
The security of
the tenure held at the time of reporting along with any known
impediments to obtaining a licence to operate in the
area.
|
·
RC drilling occurred on EL 6131, currently owned
100% by Peninsula Resources limited, a wholly owned subsidiary of
Andromeda Metals Limited.
·
Alcrest Royalties Australia Pty Ltd retains a 1.5%
NSR royalty over future mineral production from licenses EL6001,
EL5953, EL6131, EL6317 and EL6489.
·
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
REDOX 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 (pH3)
·
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 including a tabulation of the following information for 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.
|
·
Exploration results are not being reported as part
of the Mineral Resource area.
|
|
Data aggregation
methods
|
·
In reporting
Exploration Results, weighting averaging techniques, maximum and/or
minimum grade truncations (eg cutting of high grades) and cut-off
grades are usually Material and should be stated.
·
Where aggregate
intercepts incorporate short lengths of high grade results and
longer lengths of low grade results, the procedure used for such
aggregation should be stated and some typical examples of such
aggregations should be shown in detail.
·
The assumptions
used for any reporting of metal equivalent values should be clearly
stated.
|
·
Reported summary intercepts are weighted averages
based on length.
·
No maximum/ minimum grade cuts have been
applied.
·
No metal equivalent values have been
calculated.
·
Gold results are reported to a 0.3 g/t cut-off
with a maximum of 2m internal dilution with a minimum grade of 0.1
g/t Au.
·
Rare earth element analyses were originally
reported in elemental form and have been converted to relevant
oxide concentrations in line with industry standards. Conversion
factors tabulated below:
|
Element
|
Oxide
|
Factor
|
|
Cerium
|
CeO2
|
1.2284
|
|
Dysprosium
|
Dy2O3
|
1.1477
|
|
Erbium
|
Er2O3
|
1.1435
|
|
Europium
|
Eu2O3
|
1.1579
|
|
Gadolinium
|
Gd2O3
|
1.1526
|
|
Holmium
|
Ho2O3
|
1.1455
|
|
Lanthanum
|
La2O3
|
1.1728
|
|
Lutetium
|
Lu2O3
|
1.1371
|
|
Neodymium
|
Nd2O3
|
1.1664
|
|
Praseodymium
|
Pr6O11
|
1.2082
|
|
Scandium
|
Sc2O3
|
1.5338
|
|
Samarium
|
Sm2O3
|
1.1596
|
|
Terbium
|
Tb4O7
|
1.1762
|
|
Thulium
|
Tm2O3
|
1.1421
|
|
Yttrium
|
Y2O3
|
1.2699
|
|
Ytterbium
|
Yb2O3
|
1.1387
|
·
The reporting of REE oxides is done so in
accordance with industry standards with the following calculations
applied:
· TREO =
La2O3 + CeO2 +
Pr6O11 + Nd2O3 +
Sm2O3 + Eu2O3 +
Gd2O3 + Tb4O7 +
Dy2O3 + Ho2O3 +
Er2O3 + Tm2O3 +
Yb2O3 + Lu2O3 +
Y2O3
· CREO =
Nd2O3 + Eu2O3 +
Tb4O7 + Dy2O3 +
Y2O3
· LREO =
La2O3 + CeO2 +
Pr6O11 +
Nd2O3
· HREO =
Sm2O3 + Eu2O3 +
Gd2O3 + Tb4O7 +
Dy2O3 + Ho2O3 +
Er2O3 + Tm2O3 +
Yb2O3 + Lu2O3 +
Y2O3
· NdPr =
Nd2O3 +
Pr6O11
· TREO-Ce = TREO - CeO2
· % Nd =
Nd2O3/ TREO
· %Pr =
Pr6O11/TREO
· %Dy =
Dy2O3/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').
|
·
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
|
|
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.
|
·
Samples have been submitted for pressurized column
leach testing to confirm the ISR potential.
·
Hydrology, permeability and mineralogy studies
will be performed on core samples.
·
Installed wells will be used to capture baseline
hydrology data and shall be utilized for a future pilot
study.
|
Appendix 1: 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
|