Rare Earth Metallurgy Update – Head Prospect

Pre 2023

·      Historic Rotary Mud drilling targeting paleochannel hosted uranium was completed. Some residue samples were retained in the Tonsley Core Library, downhole geophysical logging was the primary data collected for these holes.

·      Select historic sample residues over Boland, Head, Stokes and Gillespie were analysed as reported in RNS 1834M (26 April 2024) and August 2025.

2023

 Aircore

·      A combination of 2m and 3m samples were collected in green bags via a rig mounted cyclone. A PVC spear was used to collect a 2-4kg sub sample from each green bag. Sampling commenced from the collar point with samples submitted for analysis from the top of saprolite.

·      Samples were submitted to Bureau Veritas Laboratories, Adelaide and pulverized to produce a 4-acid digest sample.

2024-2025

SONIC

·      Drill results are outlined in RNS 0297I (25 March 2024)

·      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 were submitted to Bureau Veritas Laboratories, Adelaide and pulverized to produce a 4 acid digest sample.

Aircore

·      1m sample intervals of 2-4 kg were taken via PVC spear from green bags at the rig. Select samples were submitted to the lab for analysis. From 0-6 m in each hole samples were composited to 3m.

·      Samples were submitted to Bureau Veritas Laboratories, Adelaide and pulverized to produce a 4 acid digest sample.

Pre 2023

·      Drill methods include Rotary Mud and AC

2023

·      Drilling completed by McLeod Drilling Pty Ltd using 75.7mm NQ air core drilling techniques from an ALMET aircore rig mounted on a Toyota Landcruiser 6x6 and a 200psi, 400cfm Sullair compressor.

2024-2025

·      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

·      Aircore Drilling completed by McLeod Drilling Pty Ltd using 75.7mm NQ air core drilling techniques from an ALMET aircore rig mounted on a Toyota Landcruiser 6x6 and a 200psi, 400cfm Sullair compressor.

·      Aircore Sample recovery is good for the style of drilling. All samples were recorded for sample type, quality and contamination potential and entered within a sample log.

·      In general, sample recoveries range between 5-10kg for each 1 m interval being recovered from AC drilling.

·      Mineralisation occurs within a confined aquifer where ground water does influence sample recovery

·      Mineralisation within the targeted Pidinga Formation is bound to fine, organic rich material, the potential loss of mineralized material from coarser host sands is possible

·      Any grade bias is expected to be grade loss

·      The potential loss of fine material is being evaluated by sizing fraction analysis and follow-up sonic core drilling where aircore holes will be twinned.

Sonic Core

·      Sample recovery is considered excellent.

·      All drill samples were logged by a qualified geologist at the time of drilling. Lithology, colour, weathering and moisture were documented. All core drilled has been lithologically logged.

·      All Aircore drill metres have been geologically logged on sample intervals (1-3 m).

·      All Sonic Core drill metres have been logged to lithological boundaries.

Pre 2023

·      Historic Residue samples were generally 2m composites and were stored at the South Australian Drill Core Reference Library at Tonsley, a subsample of approximately 20g was removed for lab submission.

·      Select samples of geological interest were selected for lab submission

·      No QAQC samples were included in the submission of these samples. Sample results were intended to indicate mineralisation potential but would not be suitable for resource estimation

Post 2023

·      A PVC spear was used to collect 2-4kg of sub-sample from each AC sample length controlled the sample volume submitted to the lab.

·      Additional sub-sampling was performed through the preparation and processing of samples according to the Bureau Veritas internal protocols.

·      Field duplicate AC samples were collected from the green bags using a PVC spear scoop at a 1 in 25 sample frequency.

·      Sample sizes are considered appropriate for the material being sampled.

·      Assessment of duplicate results indicated this sub - sample method provided appropriate repeatability for rare earths.

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 2024.

·      For 2025 drilling, quarter core was submitted to the lab for geochemical testing.

·      In holes where only column leach test samples have been submitted, full core samples have been submitted. In holes where geochemical samples were submitted three quarter core sanmples were submitted for column leach testing..

·      Samples were submitted to Bureau Veritas, Adelaide for preparation and analysis. Multi-element geochemistry were digested by four acid ICP-MS/ ICP-OES 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.  

·      Field 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 pass the companies implemented QAQC database reports

·      Internal lab blanks, standards and repeats for rare earths indicated acceptable assay accuracy.

Sample Characterisation Test Work performed by the Australian Nuclear Science and Technology Organisation (ANSTO)

·      Full core samples were submitted to Australian Nuclear Science and Technology Organisation (ANSTO), Sydney for preparation and analysis. The core was split in half along the vertical axis, and one half further split into 10 even fractions along the length of the half-core. Additional sub-sampling, homogenisation and drying steps were performed to generate ~260 g (dry equivalent) samples for head assay according to the laboratory internal protocols.

·      Multi element geochemistry of solid samples were analysed at ANSTO (Sydney) by XRF for the major gangue elements Al, Ca, Fe, K, Mg, Mn, Na, Ni, P, Si, S, and Zn.

·      Multi element geochemistry of solid samples were additionally analysed at ALS Geochemistry Laboratory (Brisbane) on behalf of ANSTO by lithium tetraborate digest ICP-MS and analysed for Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Pr, Sm, Tb, Th, Tm, U, Y and Yb.

·      Reported assays are to acceptable levels of accuracy and precision.

·      Internal laboratory blanks, standards and repeats for rare earths indicated acceptable assay accuracy.

·      Samples retained for metallurgical analysis were immediately vacuum packed, nitrogen purged and refrigerated.

·      These samples were refrigerated throughout transport.

Metallurgical Leach Test Work performed by the Australian Nuclear Science and Technology Organisation (ANSTO)

·    ANSTO laboratories prepared ~80g samples for diagnostic leaches, a 443g sample for a slurry leach and a 660g sample for a column leach. Sub-samples were prepared from full cores according to the laboratory internal protocols. Diagnostic and slurry leaching were carried out in baffled leach vessels equipped with an overhead stirrer and applying a 0.5 M (NH4)2SO4 lixiviant solution, adjusted to the select pH using H2SO4.

·    To ensure sufficient sample could be tested, down hole and near hole samples were composited 0.5 M H2SO4 was utilised to maintain the test pH for the duration of the test, if necessary. The acid addition was measured.

·    Thief liquor samples were taken periodically.

·    At the completion of each test, the final pH was measured, the slurry was vacuum filtered to separate the primary filtrate.

·    The thief samples and primary filtrate were analysed as follows:

o  ICP-MS for Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Mn, Nd, Pb, Pr, Sc, Sm, Tb, Th, Tm, U, Y, Yb.

o  ICP-OES for Al, Ca, Fe, K, Mg, Mn, Na, Si.

·    The water wash was stored but not analysed.

·    Column leaching was carried out in horizontal leaching column. The column was pressurised with nitrogen to 6 bar and submerged in a temperature controlled bath.

·    A 0.5 M (NH4)2SO4 lixiviant solution, adjusted to the select pH using H2SO4 was fed to the column at a controlled flowrate.

·    PLS collected from the end of the column was weighed, the SH and pH measured and the free acid concentration determined by titration. Liquor samples were taken from the collected PLS and analysed as follows:

o  ICP-MS for Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Mn, Nd, Pb, Pr, Sc, Sm, Tb, Th, Tm, U, Y, Yb.

o  ICP-OES for Al, Ca, Fe, K, Mg, Mn, Na, Si.

·    The column leach test has been completed. Assays of the column have adjusted head grades of the initial bench scale study. Recoveries have been adjusted accordingly.

·      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 programs showed acceptable spatial and grade repeatability.

·      Physical copies of field sampling books are retained by Cobra Resources for future reference.

·      Significant intersections have been prepared by Mr Robert Blythman and reviewed by Mr Rupert Verco

2021-2023

·      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

2024 Aircore

·      Collar locations were initially surveyed using A mobile phone GPS utilising the Avenza Map app. Collar points recorded with a horizontal accuracy within 5m.

·      Locations are recorded in geodetic datum GDA 94 zone 53.

·      No downhole surveying was undertaken on AC or Sonic holes. All holes were set up vertically and are assumed vertical.

·      Higher accuracy GPS will be undertaken on sonic core drilling to support future resource estimates

·     Drillhole spacing was designed on transects 200 to 500m apart.

·     Additional scouting holes were drilled opportunistically on existing tracks at spacings 25-150 m from previous drillholes.

·     Sonic core holes were drilled at ~20m spacings in a wellfield configuration based on assumed permeability potential of the intersected geology

·     Drillhole spacing is not expected to introduce any sample bias.

·     Assessment of the drillhole spacing for resource estimation will be made once a sufficient data set can provide statistical analysis

·     .

·     Aircore and Sonic drill holes are vertical.

·    Transport of samples to Adelaide was undertaken by a competent independent contractor. Samples were packaged in zip tied polyweave bags in bundles of 5 samples at the drill rig and transported in larger bulka bags by batch while being transported.

·    Refrigerated transport of samples to Sydney was undertaken by a competent independent contractor. Samples were double bagged, vacuum sealed, nitrogen purged and placed within PVC piping.

·    There is no suspicion of tampering of samples.

·    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.