TIDMCCZ
RNS Number : 6193C
Castillo Copper Limited
14 June 2023
14 June 2023
CASTILLO COPPER LIMITED
("Castillo", or the "Company")
Preliminary test-work findings; progress with copper assets
Castillo Copper Limited (LSE and ASX: CCZ), a base metal
explorer primarily focused on copper across Australia and Zambia,
is pleased to announce that it has received specialist consultant,
ANSTO's(1) , preliminary report on metallurgical test-work
undertaken on six samples from the Fence Gossan, Reefs, and Tors
Tanks Prospects (BHA Project's East Zone).
HIGHLIGHTS:
-- Specialist consultant, ANSTO(1) , performed metallurgical
test-work on six samples from the Fence Gossan, Reefs, and Tors
Tanks Prospects (BHA Project's East Zone) which produced the
following preliminary findings:
o The Total Rare Earth Element ("REE") plus Yttrium ("TREY")
grades for the six samples ranged from 227 to 1,632 ppm TREY;
o The proportion of high-value Magnetic Rare Earth Oxides (MREO;
Nd+Pr+Dy+Tb) to Total REO ("TREO") across the six samples ranged
from 22% to 27%; and
o The best TREY extraction, using a direct leach process at pH
1, was 30%.
-- The Board is reviewing next steps, including trialing
alternate leach tests proposed by ANSTO(1) to improve extraction
results
-- Entech Mining(2) are finishing the pit optimisation and mine
design study for the Big One Deposit (MRE: 2.1Mt @ 1.1% Cu for
21,886t2 copper metal - inferred)(3)
-- Castillo's geology team are close to completing an update on
the 2017 Mineral Resource Estimate ("MRE") for Cangai Copper
Mine(4) which will factor in results from drilling campaigns post
2017
Ged Hall, Chairman of Castillo Copper, said: "The Board is
pleased the work by ANSTO ratified the earlier assay results and
high MREO to TREO ratio. However, the Board is now reviewing
ANSTO's recommendations on how to improve the metallurgical results
from the BHA Project's East Zone. The Board's focus is now on the
Australian copper assets, with critical reports due on Cangai
Copper Mine and Big One Deposit that could aid materially in
securing development partners."
METALLURGICAL TEST-WORK FINDINGS
The metallurgical test work delivered the following
findings:
-- The TREY grades for the six samples ranged from 227 to 1,632
ppm TREY which is consistent with earlier assay results; and
-- The proportion of high-value MREO (Nd+Pr+Dy+Tb) to TREO
across the six samples ranged from 22% to 27% and aligns with
earlier calculations (Figure 1).
FIGURE 1: RARE EARTH ELEMENT COMPOSITION OF HEAD SAMPLES
(PPM)
Elements TT-002RC TT-005DD FG-003RC FG-004RC RT-001RC RT-001RC A
========== ========= ========= ========= =========
La 199 283 335 215 47 206
========== ========= ========= ========= ========= ===========
Ce 450 423 488 411 90 410
========== ========= ========= ========= ========= ===========
Pr 49 75 62 47 10 47
========== ========= ========= ========= ========= ===========
Nd 203 316 220 174 37 174
========== ========= ========= ========= ========= ===========
Sm 43 67 36 32 7 29
========== ========= ========= ========= ========= ===========
Eu 10 16 6 5 1 2
========== ========= ========= ========= ========= ===========
Gd 44 66 28 21 5 18
========== ========= ========= ========= ========= ===========
Tb 7 10 4 3 1 1
========== ========= ========= ========= ========= ===========
Dy 37 53 20 17 4 3
========== ========= ========= ========= ========= ===========
Ho 7 9 3 3 1 0
========== ========= ========= ========= ========= ===========
Er 18 26 10 8 2 0
========== ========= ========= ========= ========= ===========
Tm 2 3 1 1 0 0
========== ========= ========= ========= ========= ===========
Yb 14 21 8 7 2 0
========== ========= ========= ========= ========= ===========
Lu 2 3 1 1 0 0
========== ========= ========= ========= ========= ===========
Y 169 261 88 71 20 7
========== ========= ========= ========= ========= ===========
LREE 901 1097 1105 847 184 837
========== ========= ========= ========= ========= ===========
HREE 185 274 117 96 23 53
========== ========= ========= ========= ========= ===========
Magnets 296 454 305 241 52 226
========== ========= ========= ========= ========= ===========
TRE+Y 1254 1632 1309 1014 227 897
========== ========= ========= ========= ========= ===========
MREO 347 532 358 282 61 265
========== ========= ========= ========= ========= ===========
TREYO 1509 1958 1570 1218 273 1076
========== ========= ========= ========= ========= ===========
MREO/TREO
(%) 23.0 27.1 22.8 23.2 22.7 24.7
========== ========= ========= ========= ========= ===========
LRE = La, Ce, Pr, Nd; HRE = Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb,
Lu; Magnets = Pr, Nd, Tb, Dy; MREO = magnet oxides (Note, under
ANSTO's definition MREO comprises 4 elements, not six (Gd and
Sm not counted); TREO = Total oxides Source: ANSTO
For the metallurgy, all tests were calculated using the solid
head and the leach liquor analysis. The best TREY extraction, using
a direct leach process at pH 1, was 30% (Figure 2).
To potentially improve on these results, the Board is reviewing
recommendations put forward by ANSTO which includes:
-- Assess a wider variety of samples to validate the leach results across the East Zone; and
-- Consider additional leach tests using hydrochloric acid to
assess whether increased REE dissolution can be achieved using an
alternative lixiviant for an increased leach duration time.
FIGURE 2: SUMMARY OF LEACH EXTRACTIONS (0.5 M (NH4)2SO4
SOLUTION)
Sample ID TT-002RC TT-005DD FG003RC FG-004RC RT-001RC RT-001RC A
Head TREY (ppm) 1254 1632 1309 1014 227 897
============== ============== ============== =============== =============== ===============
Test ID CCZ-1 CCZ-7 CCZ-2 CCZ-8 CCZ-3 CCZ-9 CCZ-4 CCZ-10 CCZ-5 CCZ-11 CCZ-6 CCZ-12
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
pH 4 1 4 1 4 1 4 1 4 1 4 1
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
Duration (h) 0.5 2 0.5 2 0.5 2 0.5 2 0.5 2 0.5 2
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
Extraction (%)
=================================================================================================
La 1 2 1 2 1 3 2 4 11 33 2 3
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
Ce 1 2 1 3 1 3 2 5 11 33 2 4
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
Pr 1 2 1 2 1 3 2 5 12 32 2 3
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
Nd 1 3 1 3 1 3 2 6 11 36 2 4
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
Sm 1 4 1 3 1 4 3 6 10 32 2 5
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
Eu 4 2 3 4 5 5 20 39 12
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
Gd 1 9 1 4 2 7 2 6 9 33 1 5
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
Tb 10 2 5 6 7 35
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
Dy 1 17 2 4 2 12 3 5 6 17 7
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
Ho 20 3 5 13 8
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
Er 1 26 2 5 2 16 3 6 11
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
Tm 29 7 19
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
Yb 2 29 2 7 3 17 4 4
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
Lu 33 7 18
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
Y 2 27 2 5 3 18 2 5 5 11 4 14
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
LRE 1 2 1 3 1 3 2 5 11 34 2 4
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
HRE 1 13 2 4 2 8 3 6 7 24 1 5
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
Magnets 1 5 1 3 1 4 2 6 11 34 2 4
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
TREY 1 7 1 3 1 5 2 5 10 31 2 4
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
TREY-Ce 1 10 1 3 1 6 2 5 9 29 2 4
====== ====== ====== ====== ====== ====== ====== ======= ====== ======= ====== =======
Test methodology
A diagnostic desorption test was completed on each sample under
the following conditions:
-- 0.5 M (NH(4) )2SO(4) as lixiviant;
-- pH 4;
-- 0.5 h;
-- Ambient temperature (22 (O) C); and
-- 4 wt% solids density.
All diagnostic leach tests were carried out on pulverised
samples (80 g) at high L/S ratio, where there are no effects of
adsorption and co-precipitation. These tests indicate the maximum
extraction that could be achieved under ideal test conditions (at
more practical lower L/S ratios, extraction could be less). Where
required, 1 M H2SO4 was added to maintain the pH at 4 throughout
the test duration.
At the completion of the test, the slurry was filtered to
separate the leach liquor (PF) and the leached residue. The PF was
analysed by ICP-OES at ANSTO for gangue elements, and at ALS
Brisbane by ICP-MS for the REs and Sc, Th and U. The residue was
washed on the filter with DI water (200 mL), dried and weighed. The
water wash and residues were retained but not analysed.
A diagnostic leach test was conducted on each pulverised sample
under the following acid leach conditions:
-- 0.5 M (NH(4) )2SO(4) as lixiviant;
-- pH 1;
-- 2 h;
-- 50 (O) C; and
-- 4 wt% solids density.
The test procedure was like the foregoing method, throughout the
2h test, the pH was maintained at pH 1 where necessary by addition
of concentrated H2SO4. No intermediate thief samples were
taken.
At the completion of the test, the slurry was filtered to
separate the PF and the leached residue. The PF was analysed by
ICP-OES at ANSTO for gangue elements, and at ALS by ICP-MS for the
REs and Sc, Th and U. The residue was washed on the filter with DI
water (200 mL), dried and weighed. The residues were analysed by
XRF at ANSTO for major gangue elements and by lithium tetraborate
fusion digest/ICPMS at ALS for the REs, Sc, Th and U. The wash was
retained but not analysed.
For further information, please contact:
Castillo Copper Limited +61 8 6558 0886
Dr Dennis Jensen (Australia), Managing Director
Gerrard Hall (UK), Chairman
SI Capital Limited (Financial Adviser and
Corporate Broker) +44 (0)1483 413500
Nick Emerson
Gracechurch Group (Financial PR) +44 (0)20 4582 3500
Harry Chathli, Alexis Gore, Henry Gamble
About Castillo Copper
Castillo Copper Limited is an Australian-based explorer
primarily focused on copper across Australia and Zambia. The group
is embarking on a strategic transformation to morph into a mid-tier
copper group underpinned by its core projects:
-- A large footprint in the Mt Isa copper-belt district,
north-west Queensland, which delivers significant exploration
upside through having several high-grade targets and a sizeable
untested anomaly within its boundaries in a copper-rich region.
-- Four high-quality prospective assets across Zambia's
copper-belt which is the second largest copper producer in
Africa.
-- A large tenure footprint proximal to Broken Hill's
world-class deposit that is prospective for
zinc-silver-lead-copper-gold and platinoids.
-- Cangai Copper Mine in northern New South Wales, which is one
of Australia's highest grading historic copper mines.
The group is listed on the LSE and ASX under the ticker
"CCZ."
Competent Person's Statement
The information in this report that relates to Exploration
Results for "BHA Project, East Zone" is based on information
compiled or reviewed by Mr Mark Biggs. Mr Biggs is a director of
ROM Resources, a company which is a shareholder of Castillo Copper
Limited. ROM Resources provides ad hoc geological consultancy
services to Castillo Copper Limited. Mr Biggs is a member of the
Australian Institute of Mining and Metallurgy (member #107188) and
has sufficient experience of relevance to the styles of
mineralisation and types of deposits under consideration, and to
the activities undertaken, to qualify as a Competent Person as
defined in the 2012 Edition of the Joint Ore Reserves Committee
(JORC) Australasian Code for Reporting of Exploration Results, and
Mineral Resources. Mr Biggs holds an AusIMM Online Course
Certificate in 2012 JORC Code Reporting. Further, Mr Biggs consents
to the inclusion in this report of the matters based on information
in the form and context in which it appears.
References
1) ANSTO. Available at: https://www.ansto.gov.au/services/resources-sector/minerals
2) Entech Mining. Available at: https://entechmining.com.au
3) CCZ ASX Release - 28 February 2022 & 20 February 2023
4) CCZ ASX Release - 28 September 2018 (Annual Report 2018), 3
September 2018, 19 February 2020, 28 April 2020 & 9 March
2023
APPIX A: BHA PROJECT'S EAST ZONE
FIGURE A1: BHA PROJECT's EAST ZONE - REE EXPLORATION
FOOTPRINT
Source: CCZ geology team
FIGURE A2: BHA PROJECT
Source: CCZ geology team
APPIX B: ANSTO METALLURGICAL TESTING
Castillo identified clay-hosted REE mineralisation at its Fence
Gossan, Tors and Reefs Tanks Prospects(1) , which are within the
BHA Project's East Zone, located about 30km from Broken Hill.
Initial flotation tests showed REE minerals can be separated
from the clays by flotation to produce a higher-grade concentrate
(2-3 times REE enrichment). Castillo wants to develop an
understanding of the potential to extract the REEs contained in the
clay zones.
Castillo contacted(2) ANSTO and requested a work program to
characterise the REE/clay mineralisation with respect to RE
leachability for six samples ranging from fresh pegmatite to highly
weathered clay (see Figure B1). The MREO grades of the samples to
be supplied vary from 362 -- 603 ppm.
(1) ASX Announcements 23(rd) November 2022, and 16(th) and
28(th) February 2023.
(2) Phone call from Mark Biggs (ROM Resources, 24(th) February
2023).
FIGURE B1 SAMPLE DESCRIPTIONS
Drillhole Sample Number(s) From To Thick. Comments*
(m) (m) (m)
MREO = 466 ppm; highly
TT_002RC CCZ03888-92 14.00 19.00 5.00 weathered clay
================== ====== ====== ======= ===========================
MREO = 603 ppm; highly
TT_005DD CCZ04936-49 5.00 18.00 13.00 weathered clay
================== ====== ====== ======= ===========================
MREO = 459 ppm; Also,
Preliminary Met ALS Perth
sample; highly weathered
FG_003RC CCZ04513-30 2.00 20.00 18.00 clay
================== ====== ====== ======= ===========================
MREO = 427 ppm; highly
FG_004RC CCZ04686-91 7.00 13.00 6.00 weathered clay
================== ====== ====== ======= ===========================
MREO = 466 ppm; highly
RT_001RC CCZ03819-21 14.00 17.00 3.00 weathered clay
================== ====== ====== ======= ===========================
MREO = 362 ppm; fresh
RT_001RC CCZ04869 64.00 65.00 1.00 pegmatite
================== ====== ====== ======= ===========================
*MREO = Magnetic REEs (ANSTO definition: Pr, Nd, Tb, Dy)
Source: ANSTO
A key early question for Castillo is to establish the proportion
of ionically adsorbed REEs, and the potential for increased
extraction of the REEs by a simple direct acid leaching
approach.
Clay rare earth deposits
The so-called REE ionic clay deposits (IAD) are commercially
leached in China and Myanmar as a major source of heavy REE. A
feature of the IADs is the REEs are present as physically adsorbed
ions which can be readily solubilised by displacing the REE ions
with an appropriate cation. Typical desorption conditions are
contact with 0.3-0.5 ammonium sulfate (AS) at pH 4-5 for 30 minutes
at ambient temperature, 20-30 wt% solids. Under these conditions up
to 70% extraction (typically 40-60%) of TRE+Y can be obtained, with
very little dissolution of gangue elements, which makes for simple
downstream processing to produce a mixed REE carbonate.
Over the last few years, there have been numerous reports of
elevated concentrations of REEs associated with clays, but in most
cases the deposits have not proven to be of the classic ionic clay
type, and a lower pH has been found to be necessary to dissolve the
REE's. Under these circumstances, the economics of the process will
depend on RE extraction, acid consumption and the concentrations of
dissolved gangue elements.
An initial indication of potential economic viability can be
obtained by leaching under desorption conditions (pH 4) and a lower
pH to determine REE extraction(3) versus gangue dissolution.
(3) Total REE extraction is not necessarily the best indicator
as the individual REs will likely dissolve to different extents,
and the value of the individual REs varies significantly (the most
valuable are Nd, Pr, Tb, Dy).
Objectives and scope
The main objective of the work program is to assess the
leachability of REEs from clay samples over a range of pHs.
The specific tasks in the scope were:
o Drying of as-received samples and preparation for compositing,
assay and leach tests.
o Head assays on six samples (XRF, fusion digest/MS).
o Carry out a diagnostic leach on the 6 samples using ammonium
sulfate (AS) at pH 4.
o Carry out a diagnostic leach tests on 6 samples using ammonium
sulfate at pH 1 (in sulfuric acid).
o Provision of a data pack, with a summary note and discussion
of the main findings.
Chondrite plot
A method for providing confidence in the accuracy of the
analysis of samples containing REEs is to produce a Chondrite plot.
Normalisation against Chondrite meteorite concentrations removes
the normal 'saw tooth' distribution obtained from the concentration
profile and readily highlights differences in the relative
concentrations of individual REE's in each mineral phase or sample
(and analytical accuracy). The Chondrite plots should produce a
smooth plot across the REE series if the sample being examined has
not experienced preferential removal of elements. The Chondrite
plots for the six Castillo composites are shown in Figure B2.
The plots show a smooth transition in normalised concentration
from element to element which provides confidence in the analytical
accuracy. The Eu anomaly is normal and is indicative of weathering
through the geological history of the deposit (and is seen in
clays, monazite, xenotime, or bastnasite deposits). The slight
variation in Ce is common and may be an indication of dominant Ce
mineralogy in certain samples. The slopes of the plots indicate
that the distributions of REEs are similar in all the composites
except for RT 001RC A (fresh Pegmatite). The slope of RT-001RC A
indicates a significantly lower HRE/LRE ratio than the other five
samples.
FIGURE B2: CHONDRITE PLOT OF HEAD SAMPLES
Source: ANSTO 2023
FIGURE B3: RARE EARTH ELEMENT COMPOSITION OF HEAD SAMPLES
(PPM)
Elements TT-002RC TT-005DD FG-003RC FG-004RC RT-001RC RT-001RC A
La 199 283 335 215 47 206
========= ========= ========= ========= ========= ===========
Ce 450 423 488 411 90 410
========= ========= ========= ========= ========= ===========
Pr 49 75 62 47 10 47
========= ========= ========= ========= ========= ===========
Nd 203 316 220 174 37 174
========= ========= ========= ========= ========= ===========
Sm 43 67 36 32 7 29
========= ========= ========= ========= ========= ===========
Eu 10 16 6 5 1 2
========= ========= ========= ========= ========= ===========
Gd 44 66 28 21 5 18
========= ========= ========= ========= ========= ===========
Tb 7 10 4 3 1 1
========= ========= ========= ========= ========= ===========
Dy 37 53 20 17 4 3
========= ========= ========= ========= ========= ===========
Ho 7 9 3 3 1 0
========= ========= ========= ========= ========= ===========
Er 18 26 10 8 2 0
========= ========= ========= ========= ========= ===========
Tm 2 3 1 1 0 0
========= ========= ========= ========= ========= ===========
Yb 14 21 8 7 2 0
========= ========= ========= ========= ========= ===========
Lu 2 3 1 1 0 0
========= ========= ========= ========= ========= ===========
Y 169 261 88 71 20 7
========= ========= ========= ========= ========= ===========
LREE 901 1097 1105 847 184 837
========= ========= ========= ========= ========= ===========
HREE 185 274 117 96 23 53
========= ========= ========= ========= ========= ===========
Magnets 296 454 305 241 52 226
========= ========= ========= ========= ========= ===========
TRE+Y 1254 1632 1309 1014 227 897
========= ========= ========= ========= ========= ===========
MREO 347 532 358 282 61 265
========= ========= ========= ========= ========= ===========
TREYO 1509 1958 1570 1218 273 1076
========= ========= ========= ========= ========= ===========
MREO/TREO (%) 23.0 27.1 22.8 23.2 22.7 24.7
========= ========= ========= ========= ========= ===========
Notes:
1. LREE = La, Ce, Pr, Nd; HREE = Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu.
2. Magnets = Pr, Nd, Tb, Dy; MREO = magnet oxides.
3. TREO = Total oxides.
Source: ANSTO
FIGURE B4: GANGUE COMPOSITION OF HEAD SAMPLES
Elements Unit TT-002RC TT-005DD FG-003RC FG-004RC RT-001RC RT-001RC A
Al wt% 8.65 8.50 8.68 10.3 9.14 11.1
====== ========= ========= ========= ========= ========= ===========
Ca wt% 0.93 0.29 0.50 0.45 0.66 3.03
====== ========= ========= ========= ========= ========= ===========
Cu wt% 1.15 0.106 0.009 0.002 0.002 0.006
====== ========= ========= ========= ========= ========= ===========
Fe wt% 10.1 13.2 3.44 1.26 2.46 6.87
====== ========= ========= ========= ========= ========= ===========
K wt% 0.70 0.94 1.08 0.90 1.53 3.48
====== ========= ========= ========= ========= ========= ===========
Mg wt% 0.95 1.14 1.13 1.13 0.95 2.39
====== ========= ========= ========= ========= ========= ===========
Mn wt% 0.47 0.25 0.02 0.005 0.009 0.07
====== ========= ========= ========= ========= ========= ===========
Na wt% 1.55 0.85 4.23 6.34 4.18 2.59
====== ========= ========= ========= ========= ========= ===========
P wt% 0.05 0.07 0.04 0.11 0.05 0.05
====== ========= ========= ========= ========= ========= ===========
Sc ppm 57 48 24 29 15 10
====== ========= ========= ========= ========= ========= ===========
Si wt% 25.1 24.2 30.3 29.5 30.6 22.9
====== ========= ========= ========= ========= ========= ===========
Th ppm 2 4 17 21 18 102
====== ========= ========= ========= ========= ========= ===========
U ppm 8 14 19 10 3 8
====== ========= ========= ========= ========= ========= ===========
TREE+Y ppm 1254 1632 1309 1014 227 897
====== ========= ========= ========= ========= ========= ===========
Source: Indratti (2023)
APPIX C: JORC CODE, 2012 EDITION TABLE 1 - ANSTO METALLURGICAL
TESTING
Section 1: Sampling Techniques and Data
Criteria JORC Code explanation Commentary
Sampling Nature and quality of The samples described in Table B1 were derived
techniques sampling (e.g., cut from the EL 8434 October 2022 drilling program,
channels, random as follows:
chips, or specific Diamond Drilling (DDH)
specialised Diamond drilling of HQ diameter (TT_005DD)
industry standard was completed to 137.7m r in the completed
measurement tools program and was located 5m away from a RC hole
appropriate already drilled (TT_ 003RC).
to the minerals under Reverse Circulation ('RC') Drilling
investigation, such RC drilling at Fence Gossan with samples submitted
as for analysis using the above-mentioned methodologies
down hole gamma was used to obtain a representative sample
sondes, or handheld by means of riffle splitting.
XRF instruments, Four (4) reverse circulation (RC) holes for
etc.). These examples a total of 516m have been completed at the
should not be taken Fence Gossan Prospect.
as Four (4) RC holes were completed at Reefs Tank
limiting the broad for a total of 564m.
meaning of sampling. At Tors Tank, four (4) RC holes for a total
Include reference to of 625.7m (including the cored hole) were completed.
measures taken to The RC drilling technique was used to obtain
ensure a representative sample by means of a cone
sample representivity or riffle splitter with samples submitted for
and the appropriate assay by mixed acid digestion and analysis
calibration via ICP-MS + ICP-AES with anticipated reporting
of any measurement a suite of 48 elements (sulphur >10% by LECO)
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
(e.g.,
'reverse circulation
drilling was used to
obtain
1 m samples from
which 3 kg was
pulverised
to produce a 30g
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.
================================= =======================================================================================================
Drilling Drill type (e.g., Drilling consisted of reverse circulation,
techniques core, reverse and HQ diamond coring. One cored hole of HQ
circulation, (61mm) diameter was completed at Tors Tank
open-hole hammer, (TT005DD) after all the RC holes had been completed.
rotary air blast, Diamond drilling will be completed with standard
auger, diameter, conventional HQ and NQ with historical
Bangka, sonic, etc.) holes typically utilizing RC and percussion
and details (e.g., pre-collars to an average 30 metres (see Drillhole
core Information for further details).
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.).
================================= =======================================================================================================
Drill sample Method of recording Reverse Circulation ('RC') Drilling - Reverse
recovery and assessing core circulation sample recoveries were visually
and estimated during drilling programs. Where the
chip sample estimated sample recovery was below 100% this
recoveries and was recorded in field logs by means of qualitative
results assessed. observation.
Measures taken to Reverse circulation drilling employed sufficient
maximise sample air (using a compressor and booster) to maximise
recovery sample recovery.
and ensure Historical cored drillholes by North Broken
representative nature Hill, CRA , and Pasminco were well documented
of the samples. and generally have >90% core recovery.
Whether a No relationship between sample recovery and
relationship exists grade has been observed.
between sample
recovery and grade
and whether sample
bias
may have occurred due
to preferential
loss/gain
of fine/coarse
material.
================================= =======================================================================================================
Logging Whether core and chip The drilling that did occur was completed to
samples have been modern-day standards. In this program at all
geologically three areas holes were completed to varying
and geotechnically depths ranging from 100-220m.
logged to a level of No downhole geophysical logging took place;
detail however, measurements of magnetic susceptibility
to support were taken at the same 1m intervals as the
appropriate Mineral PXRF readings were taken.
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.
================================= =======================================================================================================
Sub-sampling If core, whether cut Core samples will be hand-split or sawn with
techniques or sawn and whether re-logging of available historical core indicating
and sample quarter, a 70:30 (retained: assayed) split was typical.
preparation half or all core The variation of sample ratios noted are considered
taken. consistent with the sub-sampling technique
If non-core, whether (hand-splitting).
riffled, tube No second half samples were submitted for analysis,
sampled, but duplicates have been taken at a frequency
rotary split, etc and of 1:20 in samples collected.
whether sampled wet It is considered water planned to be used for
or core cutting is unprocessed and unlikely to
dry. have introduced sample contamination.
For all sample types, Procedures relating to the definition of the
the nature, quality, line of cutting or splitting are not available.
and appropriateness It is expected that 'standard industry practice'
of the sample for the period was applied to maximize sample
preparation representivity.
technique. Quarter core will be submitted to ALS for chemical
Quality control analysis using industry standard sample preparation
procedures adopted and analytical techniques.
for all The sample interval details and grades quoted
sub-sampling stages for cored intervals described in various maps
to maximise in the main section are given in previous ASX
representivity releases (Castillo Copper 2022a, b, c, 2023a).
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.
================================= =======================================================================================================
Quality The nature, quality and The following rare earth elements were analysed
of assay appropriateness of using ME-MS61R Sample Decomposition is by
data and the assaying and laboratory HF-HNO(3) -HClO(4) acid digestion, HCl leach
laboratory procedures used (GEO-4A01). The Analytical Method for Silver
tests and whether the technique is shown below: Element Symbol Units Lower Upper
is considered partial Limit Limit
or total. Silver Ag ppm 0.01 100
For geophysical tools, ======== ======= ======= =======
spectrometers, handheld
XRF instruments, etc, the Inductively Coupled Plasma - Atomic Emission
parameters used in Spectroscopy (ICP - AES) Inductively Coupled
determining the analysis Plasma - Mass Spectrometry (ICP-MS)
including instrument A prepared sample (0.25 g) is digested with
make and model, reading perchloric, nitric, hydrofluoric, and hydrochloric
times, calibrations acids. The residue is topped up with dilute
factors applied and their hydrochloric acid and analysed by inductively
derivation, etc. coupled plasma atomic emission spectrometry.
Nature of quality control Following this analysis, the results are
procedures adopted reviewed for high concentrations of bismuth,
(eg standards, blanks, mercury, molybdenum, silver, and tungsten
duplicates, external and diluted accordingly.
laboratory checks) and Samples meeting this criterion are then analysed
whether acceptable levels by inductively coupled plasma-mass spectrometry.
of accuracy (i.e. lack of Results are corrected for spectral interelement
bias) and precision interferences.
have been established. Four acid digestions can dissolve most minerals:
however, although the term "near total" is
used, depending on the sample matrix, not
all elements are quantitatively extracted.
Results for the additional rare earth elements
will represent the acid leachable portion
of the rare earth elements and as such, cannot
be used, for instance to do a chondrite plot.
Geochemical Procedure
Element geochemical procedure reporting units
and limits are listed below: Element Symbol Units Lower Upper
Limit Limit
Aluminum Al % 0.01 50
======== ======== ======== ========
Arsenic As ppm 0.2 10 000
======== ======== ======== ========
Barium Ba ppm 10 10 000
======== ======== ======== ========
Beryllium Be ppm 0.05 1 000
======== ======== ======== ========
Bismuth Bi ppm 0.01 10 000
======== ======== ======== ========
Calcium Ca % 0.01 50
======== ======== ======== ========
Cadmium Cd ppm 0.02 1 000
======== ======== ======== ========
Cerium Ce ppm 0.01 500
======== ======== ======== ========
Cobalt Co ppm 0.1 10 000
======== ======== ======== ========
Chromium Cr ppm 1 10 000
======== ======== ======== ========
Cesium Cs ppm 0.05 500
======== ======== ======== ========
Copper Cu ppm 0.2 10 000
======== ======== ======== ========
Iron Fe % 0.01 50
======== ======== ======== ========
Gallium Ga ppm 0.05 10 000
======== ======== ======== ========
Germanium Ge ppm 0.05 500
======== ======== ======== ========
Hafnium Hf ppm 0.1 500
======== ======== ======== ========
Indium In ppm 0.005 500
======== ======== ======== ========
Potassium K % 0.01 10
======== ======== ======== ========
Lanthanum La ppm 0.5 10 000
======== ======== ======== ========
Lithium Li ppm 0.2 10 000
======== ======== ======== ========
Magnesium Mg % 0.01 50
======== ======== ======== ========
Molybdenum Mo ppm 0.05 10 000
========= ======= ======== ==========
Sodium Na % 0.01 10
========= ======= ======== ==========
Niobium Nb ppm 0.1 500
========= ======= ======== ==========
Nickel Ni ppm 0.2 10 000
========= ======= ======== ==========
Phosphorous P ppm 10 10 000
========= ======= ======== ==========
Lead Pb ppm 0.5 10 000
========= ======= ======== ==========
Rubidium Rb ppm 0.1 10 000
========= ======= ======== ==========
Rhenium Re ppm 0.002 50
========= ======= ======== ==========
Sulphur S % 0.01 10
========= ======= ======== ==========
Antimony Sb ppm 0.05 10 000
========= ======= ======== ==========
Scandium Sc ppm 0.1 10 000
========= ======= ======== ==========
Selenium Se ppm 1 1 000
========= ======= ======== ==========
Tin Sn ppm 0.2 500
========= ======= ======== ==========
Strontium Sr ppm 0.2 10 000
========= ======= ======== ==========
Tantalum Ta ppm 0.05 100
========= ======= ======== ==========
Tellurium Te ppm 0.05 500
========= ======= ======== ==========
Thorium Th ppm 0.2 10 000
========= ======= ======== ==========
Titanium Ti % 0.005 10
========= ======= ======== ==========
Thallium Tl ppm 0.02 10 000
========= ======= ======== ==========
Uranium U ppm 0.1 10 000
========= ======= ======== ==========
Vanadium V ppm 1 10 000
========= ======= ======== ==========
Tungsten W ppm 0.1 10 000
========= ======= ======== ==========
Method ME-MS81
This method involves a lithium borate fusion
prior to acid dissolution and ICP- MS analysis
provides the most quantitative analytical
approach for a broad suite of trace elements.
Options for adding the whole rock elements
from an |CP - AES analysis on the same fusion,
or base metals from a separate four acid
digestion, are available.
Lower and upper detection limits are given
below: Element Symbol Units Lower Upper
Limit Limit
Yttrium Y ppm 0.1 500
======== ======= ======= =======
Zinc Zn ppm 2 10 000
======== ======= ======= =======
Zirconium Zr ppm 0.5 500
======== ======= ======= =======
Dysprosium Dy ppm 0.05 1 000
======== ======= ======= =======
Erbium Er ppm 0.03 1 000
======== ======= ======= =======
Europium Eu ppm 0.03 1 000
======== ======= ======= =======
Gadolinium Gd ppm 0.05 1 000
======== ======= ======= =======
Holmium Ho ppm 0.01 1 000
======== ======= ======= =======
Lutetium Lu ppm 0.01 1 000
======== ======= ======= =======
Neodymium Nd ppm 0.1 1 000
======== ======= ======= =======
Praseodymium Pr ppm 0.03 1 000
======== ======= ======= =======
Samarium Sm ppm 0.03 1 000
======== ======= ======= =======
Terbium Tb ppm 0.01 1 000
======== ======= ======= =======
Thulium Tm ppm 0.01 1 000
======== ======= ======= =======
Ytterbium Yb ppm 0.03 1 000
======== ======= ======= =======
* Laboratory inserted standards, blanks and duplicates
were analysed per industry standard practice. There
was no evidence of bias from these results.
================================= =======================================================================================================
Verification The verification of
of sampling significant * Two of the drillholes have been twinned, at Tors Tank
and assaying intersections where TT_005DD was drilled next to TT_003RC.
by either independent
or alternative
company * Conversion of elemental analysis (REE parts per
personnel. million) to stoichiometric oxide (REO parts per
The use of twinned million) was undertaken by ROM geological staff using
holes. the below element to stoichiometric oxide conversion
Documentation of factors
primary data, data (https://www.jcu.edu.au/news/releases/2020/march/rare-earth-metals-an-untapped-resource)
entry
procedures, data
verification, data
storage
(physical and Table C1-1: Element -Conversion Factor -Oxide
electronic) Form
protocols. Ce 1.2284 CeO(2)
Discuss any ============== ===================
adjustment to assay Dy 1.1477 Dy(2) O(3)
data. ============== ===================
Er 1.1435 Er(2) O(3)
============== ===================
Eu 1.1579 Eu(2) O(3)
============== ===================
Gd 1.1526 Gd(2) O(3)
============== ===================
Ho 1.1455 Ho(2) O(3)
============== ===================
La 1.1728 La(2) O(3)
============== ===================
Lu 1.1371 Lu(2) O(3)
============== ===================
Nd 1.1664 Nd(2) O(3)
============== ===================
Pr 1.2083 Pr(6) O(11)
============== ===================
Sm 1.1596 Sm(2) O(3)
============== ===================
Tb 1.1762 Tb(4) O(7)
============== ===================
Tm 1.1421 Tm(2) O(3)
============== ===================
Y 1.2699 Y(2) O(3)
============== ===================
Yb 1.1387 Yb(2) O(3)
============== ===================
Rare earth oxide is the industry accepted form
for reporting rare earths. The following calculations
are used for compiling REO into their reporting
and evaluation groups:
TREO (Total Rare Earth Oxide) = 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) + Y(2) O(3) + Lu(2) O(3)
.
TREO-Ce = TREO - CeO(2)
LREO (Light Rare Earth Oxide) = La(2) O(3)
+ CeO(2) + Pr(6) O(11) + Nd(2) O(3) + Sm(2)
O(3)
HREO (Heavy Rare Earth Oxide) = Eu(2) O(3)
+ Gd(2) O(3) + Tb(4) O(7) + Dy(2) O(3) + Ho(2)
O(3) + Er(2) O(3) + Tm2O3 + Yb2O3 + Y2O3 +
Lu2O3
CREO (Critical Rare Earth Oxide) = Nd(2) O(3)
+ Eu(2) O(3) + Tb(4) O(7) + Dy(2) O(3) + Y(2)
O(3)
MREO (Magnetic Rare Earth Oxide) = Pr(6) O(11)
+ Nd(2) O(3) + Tb(4) O(7) + Dy(2) O(3) . (as
advised by ANSTO)
Previously, Castillo Copper had reported MREO
(Magnetic Rare Earth Oxide) as = Pr(6) O(11)
+ Nd(2) O(3) + Sm(2) O(3) + Gd(2) O(3) + Tb(4)
O(7) + Dy(2) O(3) .
Total Rare Earth Oxides (TREO) Example Calculation:
To calculate TREO an oxide conversion "factor"
is applied to each rare-earth element assay.
The "factor" equates an elemental assay to
an oxide concentration for each element. Below
is an example of the factor calculation for
Lanthanum (La):
o Relative Atomic Mass (La) = 138.9055
o Relative Atomic Mass (O) = 15.9994
o Oxide Formula = La(2) O(3)
o Oxide Conversion Factor = 1/ ((2x 138.9055)/(2x
138.9055 + 3x 15.9994)) Oxide Conversion Factor
= 1.173 (3dp)
None of the historical data has been adjusted.
================================= =======================================================================================================
Location Accuracy and quality All drillholes and samples have been converted
of data of surveys used to to MGA94 (Zone 54). The holes were originally
points locate surveyed with handheld GPS, and were subsequently
drill holes (collar resurveyed by a more accurate DGPS survey from
and down-hole GMC Surveying. It is thus estimated that locational
surveys), accuracy therefore varies between 0.1-0.2m
trenches, mine The quality of topographic control (a combination
workings and other of drone survey over the Fence Gossan area
locations and GSNSW 1 sec DEM for the remainder) is deemed
used in Mineral adequate for the purposes of the exploration
Resource estimation. drilling program.
Specification of the
grid system used.
Quality and adequacy
of topographic
control.
================================= =======================================================================================================
Data spacing Data spacing for The average sample spacing from the current
and reporting of drilling program across the tenure varies per
distribution Exploration prospect, and sample type, as listed in Table
Results. C1-2, below:
Whether the data
spacing, and
distribution Table C1-2: EL 8434 Drillhole Spacing Prospect Drillholes RMS Drillhole
is sufficient to Completed Spacing
establish the degree (m)
of geological The Sisters Not yet
and grade continuity =========== ==============
appropriate for the Iron Blow Not Yet
Mineral =========== ==============
Resource and Ore Tors Tank 4 127
Reserve estimation =========== ==============
procedure(s) Fence Gossan 4 208
and classifications =========== ==============
applied. Ziggy's n/a n/a
Whether sample Hill
compositing has been =========== ==============
applied. Reefs Tank 1 n/a
=========== ==============
The Datamine software allows creation of fixed
length samples from the original database given
a set of stringent rules.
Sample locations were previously shown by plans
in Castillo Copper (2023a).
================================= =======================================================================================================
Orientation Whether the Historical drill holes at the BHAE are typically
of data orientation of drilled vertically for auger and RAB types
in relation sampling achieves (drilled along section lines) and angled at
to unbiased sampling of -55˚ or -60˚ to the horizontal and
geological possible structures drilled perpendicular to the mineralised trend
structure and for RC and DDH.
the extent to which Drilling orientations are adjusted along strike
this is known, to accommodate folded geological sequences.
considering All Fence Gossan holes were designed to drill
the deposit type. toward grid south at an inclination of 60 degrees
If the relationship from horizontal.
between the drilling The drilling orientation is not considered
orientation to have introduced a sampling bias on assessment
and the orientation of the current geological interpretation.
of key mineralised Geological mapping by various companies has
structures reinforced that the strata dips variously between
is considered to have 5 and 65 degrees.
introduced a sampling
bias, this should be
assessed and reported
if material.
================================= =======================================================================================================
Sample The measures taken to Sample security procedures are considered 'industry
security ensure sample standard' for the current period.
security. Samples obtained during drilling completed
between 4/10/22 to the 10/10/22 were transported
by exploration employees or an independent
courier directly from Broken Hill to ALS Laboratory,
Adelaide. Samples selected for metallurgical
testing were then shipped to ANSTO in Sydney
NSW.
The Company considers that risks associated
with sample security are limited given the
nature of the targeted mineralisation.
================================= =======================================================================================================
Audits The results of any No external audits or reviews have yet been
or reviews audits or reviews of undertaken. The reporting of head grades by
sampling ANSTO internal laboratory work matches that
techniques and data. previously reported by ALS work conducted on
behalf of Castillo Copper (Biggs 2023; Castillo
Copper 2023a).
================================= =======================================================================================================
SECTION 2: REPORTING OF EXPLORATION RESULTS
Criteria JORC Code explanation Commentary
Mineral Type, reference EL 8434 is located about 28km east of Broken
tenement name/number, Hill whilst EL 8435 is 16km east of Broken
and land location and Hill. Both tenures are approximately 900km
tenure status ownership northwest of Sydney in far western New South
including Wales (Figures C2-1 and C2-2 in Appendix A,
agreements or above).
material EL 8434 and EL 8435 were both granted on the
issues with 2(nd of) June 2016 to Squadron Resources for
third parties a term of five (5) years for Group One Minerals.
such as joint On the 25(th of) May 2020, Squadron Resources
ventures, changed its name to Wyloo Metals Pty Ltd (Wyloo).
partnerships, In December 2020 the tenure was transferred
overriding from Wyloo Metals to Broken Hill Alliance Pty
royalties, Ltd a 100% subsidiary company of Castillo Copper
native Limited. Both tenures were renewed on the 12(th
title interests, of) August 2021 for a further six (6) years
historical and are due to expire on the 2(nd of) June
sites, 2027.
wilderness EL 8434 lies across two (2) 1:100,000 geology
or national park map sheets Redan 7233 and Taltingan 7234, and
and two (2) 1:250,000 geology map sheets, SI54-3
environmental Menindee, and SH54-15 Broken Hill in the county
settings. of Yancowinna. EL 8434 consists of one hundred
The security of and eighty-six (186) units) in the Adelaide
the tenure held and Broken Hill 1:1,000,000 Blocks covering
at the time an area of approximately 580km(2) .
of reporting EL 8435 is located on the 1:100,000 geology
along with any map sheet Taltingan 7234, and the 1:250,000
known geology map sheet SH/54-15 Broken Hill in the
impediments county of Yancowinna. EL 8435 consists of twenty-two
to obtaining a (22) units (Table 1) in the Broken Hill 1:1,000,000
licence to Blocks covering an area of approximately 68km(2)
operate in the .
area. Access to the tenures from Broken Hill is via
the sealed Barrier Highway. This road runs
north-east to south-west through the northern
portion of EL 8434, passes the southern tip
of EL 8435 eastern section and through the
middle of the western section of EL 8435. Access
is also available via the Menindee Road which
runs north-west to south-east through the southern
section of the EL 8434. The Orange to Broken
Hill Rail line also dissects EL 8435 western
section the middle and then travels north-west
to south-east slicing through the eastern arm
of EL 8434 (Figure C2-1).
Figure C2-1: EL 8434 and EL 8435 General Location
Map
============================ =================================================================
Exploration Acknowledgment Explorers who were actively involved over
done by other and appraisal of longer
parties exploration historical periods in various parts of EL8434
by other were: - North Broken Hill Ltd, CRAE
parties. Exploration,
Major Mining Ltd and Broken Hill Metals NL,
Pasminco Exploration Ltd, Normandy Exploration
Ltd, PlatSearch NL/Inco Ltd/ EGC Pty Ltd JV
and the Western Plains Gold Ltd/PlatSearch/EGC
Pty Ltd JV.
A comprehensive summary of work by previous
explorers was presented in Leyh (2009).
However,
more recently, follow-up field reconnaissance
of areas of geological interest, including
most of the prospective zones, was carried
out by EGC Pty Ltd over the various licenses.
This work, in conjunction with a detailed
interpretation
of aeromagnetic, gravity plus RAB / RC drill
hole logging originally led to the
identification
of at least sixteen higher priority prospect
areas. All these prospects were summarized
in considerable detail in Leyh (2008). Future
work programs were then also proposed for each
area. Since then, further compilation work
plus detailed geological reconnaissance mapping
and sampling of gossans and lode rocks has
been carried out.
A total of 22 prospects were then recognised
on the exploration licence with at least 12
occurring in and around the tenure.
With less than 45% outcropping Proterozoic
terrain within the licence, this makes it very
difficult to explore and is in the main very
effectively screened from the easy application
of more conventional exploration methodologies
due to a predominance of extensive Cainozoic
cover sequences. These include recent to young
Quaternary soils, sands, clays and older more
resistant, only partially dissected, Tertiary
duricrust regolith covered areas. The depth
of the cover ranges from a few metres in the
north to over 60 metres in some areas on the
southern and central license.
Exploration by EGC Pty Ltd carried out in the
field in the first instance has therefore been
heavily reliant upon time consuming systematic
geological reconnaissance mapping and relatable
geochemical sampling. These involve a slow
systematic search over low outcropping areas,
poorly exposed subcrop and float areas as well
as the progressive development of effective
regolith mapping and sampling tools. This work
has been combined with a vast amount of
intermittently
acquired past exploration data. The recent
data compilation includes an insufficiently
detailed NSWGS regional mapping scale given
the problems involved, plus some regionally
extensive, highly variable, low-level stream
and soil BLEG geochemical data sets over much
of the area.
There are also a few useful local detailed
mapping grids at the higher priority prospects,
and many more numerous widespread regional
augers, RAB, and percussion grid drilling data
sets. Geophysical data sets including ground
magnetics, IP and EM over some prospect areas
have also been integrated into the exploration
models. These are located mainly in former
areas of moderate interest and most of the
electrical survey methods to date in this type
of terrain continue to be of limited
application
due to the high degree of weathering and the
often prevailing and complex regolith cover
constraints.
Between 2007 and 2014 Eaglehawk Geological
Consulting has carried out detailed research,
plus compilation and interpretation of a very
large volume of historic exploration data
sourced
from numerous previous explorers and dating
back to the early 1970's. Most of this data
is in non-digital scanned form. Many hard copy
exploration reports (see references) plus
several
hundred plans have been acquired from various
sources, hard copy printed as well as
downloaded
as scans from the Geological Survey of NSW
DIGS system. They also conducted field mapping,
costean mapping and sampling, and rock chip
sampling and analysis.
Work Carried out by Squadron Resources and
Whyloo Metals 2016-2020
Research during Year 1 by Squadron Resources
revealed that the PGE-rich, sulphide-bearing
ultramafic rocks in the Broken Hill region
have a demonstrably alkaline affinity. This
indicates a poor prospectivity for economic
accumulations of sulphide on an empirical basis
(e.g., in comparison to all known economic
magmatic nickel sulphide deposits, which have
a dominant tholeiitic affinity). Squadron
instead
directed efforts toward detecting new Broken
Hill-Type (BHT) deposits that are synchronous
with basin formation. Supporting this modified
exploration rationale are the EL's
stratigraphic
position, proximity to the Broken Hill line
of lode, abundant mapped alteration (e.g.,
gahnite and/or garnet bearing exhalative units)
and known occurrences such as the "Sisters"
and "Iron Blow" prospects.
The area overlies a potential magmatic
Ni-Cu-PGE
source region of metasomatised sub-continental
lithospheric mantle (SCLM) identified from
a regional targeting geophysical database.
The exploration model at the time proposed
involved remobilization of Ni-Cu-PGE in SCLM
and incorporation into low degree
mafic-ultramafic
partial melts during a post-Paleoproterozoic
plume event and emplacement higher in the crust
as chonoliths/small intrusives - Voisey's Bay
type model. Programs were devised to use
geophysics
and geological mapping to locate secondary
structures likely to control and localise
emplacement
of Ni-Cu-PGE bearing chonoliths. Since EL8434
was granted, the following has been completed:
* Airborne EM survey.
* Soil and chip sampling.
* Data compilation.
* Geological and logistical reconnaissance.
* Community consultations; and
* Execution of land access agreements
.
Airborne EM Survey
Geotech Airborne Limited was engaged to conduct
an airborne EM survey using their proprietary
VTEM system in 2017. A total of 648.92-line
kilometres were flown on a nominal 200m line
spacing over a portion of the project area.
Several areas were infilled to 100m line
spacing.
The VTEM data was interpreted by Southern
Geoscience
Consultants Pty Ltd, who identified a series
of anomalies, which were classified as high
or low priority based on anomaly strength
(i.e.,
does the anomaly persist into the latest
channels).
Additionally, a cluster of VTEM anomalies at
the "Sisters" prospect have been classified
separate due to strong IP effects observed
in the data. Geotech Airborne have provided
an IP corrected data and interpretation of
the data has since been undertaken.
Soil and Chip sampling
The VTEM anomalies were followed up by a
reconnaissance
soil sampling programme. Spatially clustered
VTEM anomalies were grouped, and follow-up
soil lines were designed. Two (2) VTEM
anomalies
were found to be related to culture and
consequently
no soils were collected. Two (2) other
anomalies
were sampled which were located above thick
alluvium of Stephens Creek and were therefore
not sampled. A line of soil samples was
collected
over a relatively undisturbed section at Iron
Blow workings and the Sisters Prospect.
One hundred and sixty-six (166) soil samples
were collected at a nominal 20cm depth using
a 2mm aluminum sieve. Two (2) rock chips were
also collected during this program. The samples
were collected at either 20m or 40m spacing
over selected VTEM anomalies. The samples were
pulverised and analysed by portal XRF at ALS
laboratories in Perth.
Each site was annotated with a "Regolith
Regime"
such that samples from a depositional
environment
could be distinguished from those on exposed
Proterozoic bedrock, which were classified
as an erosional environment. The Regolith
Regime
groups were used for statistical analysis and
levelling of the results. The levelled data
reveals strong relative anomalies in zinc at
VTEM anomaly clusters 10, 12 and 14 plus strong
anomalous copper at VTEM 17.
============================ =================================================================
Geology Deposit type, As the strata is tightly folded, the intersected
geological cobalt-rich layers are overstated in terms
setting, and of apparent thickness, however the modelling
style software calculates a true, vertical thickness.
of Cobalt mineralisation is commonly associated
mineralisation. with shears, faults, amphibolites, and a
quartz-magnetite
rock within the shears, or on or adjacent to
the boundaries of the Himalaya Formation. In
general, most of the cobalt and rare earth
element - rich layers have a north-northwest
to north strike.
REE enrichment generally occurs as a 5 to
10-metre-thick
zone between the completely weathered layer
and strongly weathered layer and it is targeted
for commercial mining (Figure D2-2). Compared
to other REE deposits, regolith-hosted rare
earth element deposits are substantially low-moderate
grade (containing 0.05-0.3 wt.% extractable
REEs). Nevertheless, due to its easy extraction
method, low processing costs and large abundance,
the orebodies are generally economic to be
extracted ( Duuring, (2020); Kanazawa and Kamitani
(2006); and Murakami, H.; Ishihara (2008) ).
Figure C2-2: Weathering Profile over REE -
Rich Granite
https://en.wikipedia.org/wiki/Regolith-hosted_rare_ea
rth_element_deposits
Weathering profile of regolith hosted REE deposits
shown above, the legend is: (A) Humic layer.
(B) Completely weathered layer. (C) Strongly
weathered layer. (D) Weathering front. (E)
Unweathered rock.
Most of the REE found in cerium monazite (Ce
(PO(4) )) which always contains major to minor
amounts of other REE (Nd, La, Pr, Sm etc) replacing
Ce. Also, the mineral often contains trace
amounts of U and Th (coupled with Ca). This
will be collaborated with XRD and/or SEM analysis.
============================ =================================================================
Drill hole A summary of all Header information about all drillholes and
Information information surface samples completed at Reefs Tank, Tors
material to Tank and Fence Gossan have been tabulated in
the this release in Appendix B.
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.
============================ =================================================================
Data aggregation In reporting No metal equivalents have been reported. Rare
methods Exploration earth element results have been converted to
Results, rare earth oxides as per standard industry
weighting practice (Castillo Copper 2022c, 2023a).
averaging No compositing of assay results has taken place,
techniques, but rather menu options within the Datamine
maximum and/or GDB module have been used to create fixed length
minimum 1m assay intervals from the original sampling
grade lengths.
truncations The rules follow very similarly to those used
(e.g., cutting by the Leapfrog Geo software in creating fixed
of high length samples.
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.
============================ =================================================================
Relationship These A database of all the historical borehole sampling
between relationships has been compiled and validated. It is uncertain
mineralisation are particularly if there is a strong relationship between the
widths and important surface sample anomalies to any subsurface
intercept in the reporting anomalous intersections due to the possible
lengths of Exploration masking by variable Quaternary and Tertiary
Results. overburden that varies in depth from 0-15m.
If the geometry The mineralisation appears to be secondary
of the enrichment in the regolith clays and extremely
mineralisation weathered material derived from quartzo-feldspathic
with pegmatites.
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
(e.g., 'down
hole
length, true
width not
known').
============================ =================================================================
Diagrams Appropriate maps Current surface anomalies are shown on maps
and sections released on the ASX (Castillo Copper 2022a,
(with scales) 2022b, 2022c and 2023a). All historical surface
and tabulations sampling has had their coordinates converted
of intercepts to MGA94, Zone 54.
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.
============================ =================================================================
Balanced Where All recent laboratory analytical results have
reporting comprehensive been recently reported (see Castillo Copper
reporting of all 2022a, b, c, 2023a) for assay results.
Exploration Regarding the surface and sampling, no results
Results is not other than duplicates, blanks or reference
practicable, standard assays have been omitted.
representative
reporting of
both low and
high grades
and/or
widths should be
practiced to
avoid misleading
reporting of
Exploration
Results.
============================ =================================================================
Other substantive Other Historical explorers have also conducted airborne
exploration exploration and ground gravity, magnetic, EM, and IP resistivity
data data, if surveys over parts of the tenure area but this
meaningful and is yet to be fully georeferenced (especially
material, should the ground IP surveys). Squadron Resources
be reported conducted an airborne EM survey in 2017 that
including (but covers Iron Blow and The Sisters, but not the
not limited to): southern cobalt and REE prospect areas.
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.
============================ =================================================================
Further The nature and It is recommended that:
work scale of planned * Assess a wider variety of samples to validate the
further leach results across the deposit.
work (e.g.,
tests for
lateral * Consider QEMSCAN mineralogy to identify possible REE
extensions phases. This would confirm the reason for low
or depth extractions and inform the likelihood of increased
extensions or dissolution under more aggressive acid leach
large-scale conditions. It would also inform the possibility of
step-out upgrading the REE content by beneficiation (e.g.,
drilling). screening); and
Diagrams clearly
highlighting the
areas * Consider additional leach tests using hydrochloric
of possible acid to assess whether increased REE dissolution can
extensions, be achieved using an alternative lixiviant for an
including the increased leach duration time but noting that a
main moderate acidity is still likely to be required,
geological which would likely prove to be uneconomic.
interpretations
and future
drilling
areas, provided
this information
is not
commercially
sensitive.
============================ =================================================================
TABLE 1 REFERENCES
Biggs, M.S., 2023, Metallurgy Testing at ANSTO Started,
unpublished memo for Castillo Copper Limited, ROM Resources, Mar
2023,3pp.
Castillo Copper Limited, 2022a ASX Release, Drilling hits
targeted cobalt zones & wide pegmatite intercepts at Broken
Hill 12 October 2022
Castillo Copper Limited, 2022b ASX Release, Drilling hits more
wide pegmatite intercepts at Broken Hill, 24 October 2022
Castillo Copper Limited, 2022c ASX Release, Completed auger
sampling campaign targets 6.5km2 REE mineralisation zone, 23
December 2022
Castillo Copper Limited, 2023a ASX Release, MREO focused
metallurgical test-work underway by ANSTO, 13 April 2023.
Datta, I., 2023, Technical memo, Scoping Tests for rare earth
recovery, prepared for Castillo Copper Limited, Jun23, 14pp.
Duuring, P 2020, Rare-element pegmatites: a mineral systems
analysis: Geological Survey of Western Australia, Record 2020/7,
6p.
Evenson, N. M., Hamilton, P. J. and O'Nions, R. K. (1978) "Rare
Earth Abundances in Chondrite Meteorites" Geochimica et
Cosmochimica Acta 42, 1199-1212.
Kanazawa, Y.; Kamitani, M., 2006, "Rare earth minerals and
resources in the world". Journal of Alloys and Compounds. 408:
1339-1343. doi:10.1016/j.jallcom.2005.04.033
Mohoney, M., 2018, BHA Broken Hill Project Position Paper,
Squadron Resources Pty Ltd., Unpublished report, Mar2018, 8pp.
Mortimer R., 2017, Re-interpretation of VTEM Profiles Broken
Hill Area, unpublished report by Southern Geoscience Consultants
for Squadron Resources Pty Ltd, Oct 17.
https://en.wikipedia.org/wiki/Regolith-hosted_rare_earth_element_deposits
Murakami, H.; Ishihara, S., 2008, REE mineralization of
weathered crust and clay sediment on granitic rocks in the Sanyo
Belt, SW Japan and the Southern Jiangxi Province, China". Resource
Geology. 58 (4): 373-401. doi:10.1111/j.1751-3928.2008.00071.x.
Willis, I.L., Brown, R.E., Stroud, W.J., Stevens, B.P.J., 1983,
The Early Proterozoic Willyama Supergroup: stratigraphic
subdivision and interpretation of high to low-grade metamorphic
rocks in the Broken Hill Block, New South Wales., Geological
Society of Australia Journal, 30(2), p195-2
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