REG - Castillo Copper Ltd - Data review boosts exploration potential of Arya
13/04/2021 07:00
For best results when printing this announcement, please click on link below:
http://newsfile.refinitiv.com/getnewsfile/v1/story?guid=urn:newsml:reuters.com:20210413:nRSM2179Va&default-theme=true
RNS Number : 2179V Castillo Copper Limited 13 April 2021
13 April 2021
CASTILLO COPPER LIMITED
("Castillo" or the "Company")
Review of BHP & MIM data boosts exploration potential of Arya Prospect
Castillo Copper Limited (LSE and ASX: CCZ), a base metal explorer primarily
focused on copper across Australia and Zambia, is pleased to announce that a
review of historical reports undertaken by BHP and Mt Isa Mines ("MIM") has
provided compelling insights and further enhanced the exploration potential of
the Arya Prospect ahead of a resumption in the drilling campaign at the Mt
Oxide Project in the Mt Isa copper-belt district of Queensland, Australia.
Highlights
· Castillo's geology team reviewed key historical reports - including
several commissioned by BHP and MIM in the 1990s - that enhance the Arya
Prospect's exploration potential
· In a 1997 annual tenement report, BHP identified 11 GEOTEM anomalies
worthy of attention (now in Castillo's tenure), however ground geophysics and
rock chip sampling was only completed on four (leaving seven viable targets
yet to be investigated):
o At the time, BHP rated EG01 - which is interpreted to be a 130m thick
potential massive sulphide bedrock conductor (1,500m by 450m and circa 430m
deep) - as a priority drill-test target
o Secondary targets, comprising EG02 and EG10, are interpreted to be shallow
(~25m), 25m thick - with respective dimensions 160m by 50m and 280m by 270m -
may contain supergene copper mineralisation
· Using aggregated historical rock-chip assay data - up to 1.84% Cu
(MIM) - Castillo's geology team created a maiden copper heat map which
seamlessly reconciles with geophysical findings to boost confidence in
drill-test targets at the Arya Prospect
· To garner better insights of the upcoming drilling campaign,
comprising 3,625m across 14 drill-holes, Castillo's geology team, utilising 3D
modelling to facilitate generating optimal results, have planned:
o Three deep vertical drill-holes, spaced 210m apart, and ranging from
590-680m to test EG01, while 11 shallower drill-holes will focus on EG02, EG10
and three highly anomalous peaks along the fault
· In a fresh development, another deep bedrock conductor has been
identified at the newly named Sansa Prospect, which is immediately west of the
Arya Prospect:
o Encouragingly, there are elevated surface copper readings at the Sansa
Prospect - above the bedrock conductor - though further interpretation work is
required to formulate dimensions and assess the geological potential
Simon Paull, Managing Director of Castillo Copper, commented: "The Board is
very much looking forward to resuming drilling at the Mt Oxide Project,
especially the Arya Prospect which has increasingly compelling attributes.
While our main goal is to drill-test our primary target, EG01, the overall
exploration potential has been boosted with a further seven targets identified
by BHP and the Sansa Prospect."
COMPELLING CASE FOR ARYA PROSPECT
With the drilling campaign at the Mt Oxide Project set to resume, Castillo's
geology team undertook another detailed review of all key historical reports,
especially those commissioned by BHP and MIM, on the Arya Prospect.
Of significance, in BHP's 1997 Annual Report for EPM11452, which is now part
of Castillo's tenure, the following quotes underscore the Arya Prospect's
exploration potential:
"11 GEOTEM anomalies were identified as worth further attention, four of these
have been followed up with ground TEM work and selective rock chip sampling."
"EG01 is considered a priority target. Drill testing here is recommended.
There are also a number of priority 2 targets which will require further
work."
Subsequently, Castillo's geology team has interpreted EG01 as a 130m thick
potential massive sulphide bedrock conductor that is circa 426m deep with
dimensions 1,500m by 450m. Meanwhile, the secondary targets, EG02 and EG10,
are much shallower (~25m), 25m thick with dimensions 160m by 50m and 280m by
270m respectively. Current interpretations suggest that both these anomalies
may contain supergene copper mineralisation.
Copper heat map
Using aggregated historical surface data, Castillo's geology team have created
'copper heat maps' which show the extent of mineralisation across the Arya and
Sansa Prospects. The effect is quite pronounced when using data for rock chip
assays from various campaigns done by the likes of BHP and MIM which achieved
results up to 7,400ppm Cu and 18,400ppm Cu respectively.
A key benefit from utilising the copper heat map is reconciling historical
surface geochemistry assays with geophysical survey results, as this bolsters
the confidence in drill-test targets selected at the Arya Prospect. The
copper heat map can be seen in the PDF version of this announcement on the
Company's website: https://www.castillocopper.com/asx-announcements/
(https://www.castillocopper.com/asx-announcements/)
Castillo's geology team have interpreted EG01 to be a down plunge extension of
brecciated copper mineralisation currently identified at surface. Notably,
high surface rock chips for copper exist in interpreted up dip extensions from
the main sulphide body representing a structurally controlled copper deposit.
Interestingly, EG01 was originally discovered by BHP in 1997, post an airborne
electro-magnetic ("AEM") survey as it gave off a strong response. However, no
follow up work was done at the time, possibly due to the downturn in base
metals in the late 1990s.
In March 2019, Geoscience Australia released the results of an AEM survey
which identified EG01 within Castillo's tenure, precipitating considerable
forensic work to uncover more details. This resulted in a comprehensive review
of legacy reports, highlighted above, coupled with assertions the Arya
Prospect has potential for IOCG mineralisation.
In a fresh development, another deep bedrock conductor was identified at the
Sansa Prospect which is immediately west of the Arya Prospect. However,
further interpretation work is required to determine the dimensions and
ascertain the exploration potential for copper mineralisation.
Drilling campaign in 3D
To provide greater context and better insights to the upcoming drilling
campaign at the Arya Prospect, the geology team initiated utilising 3D
modelling technology to generate optimal results. The program comprises 14
drill-holes for 3,625m.
· Three deep vertical drill-holes, spaced 210m apart and ranging from
590-680m, are set to test EG01
· 11 shallower drill-holes will test EG02, EG10 and three highly
anomalous peaks along the fault that runs through the Arya Prospect
Next steps
Upcoming site visits by Castillo's geology team and geophysical contractors to
respectively work on pre-drilling logistics and IP survey at the Big One
Deposit.
Drilling team schedule to return to site to commence work at the Big One
Deposit then move on to the Arya Prospect.
In addition to this release, a PDF version of this report with supplementary
information can be found on the Company's website:
https://www.castillocopper.com/asx-announcements/
(https://www.castillocopper.com/asx-announcements/)
For further information, please contact:
Castillo Copper Limited +61 8 6558 0886
Simon Paull (Australia), Managing Director
Gerrard Hall (UK), Director
SI Capital Limited (Financial Adviser and Corporate Broker) +44 (0)1483 413500
Nick Emerson
Luther Pendragon (Financial PR) +44 (0)20 7618 9100
Harry Chathli, Alexis Gore, Joe Quinlan
ABOUT CASTILLO COPPER
Castillo Copper Limited is an Australian-based explorer primarily focused on
copper across Australia and Zambia. The Company is embarking on a strategic
transformation to morph into a mid-tier copper group underpinned by its core
projects:
· The Mt Oxide project 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.
· Cangai Copper Mine in northern New South Wales, which is one of
Australia's highest grading historic copper mines.
The Company is listed on the LSE and ASX under the ticker "CCZ."
Competent Person Statement
The information in this report that relates to Exploration Results for "Big
One Deposit" is based on information compiled or reviewed by Mr Mark Biggs.
Mr Biggs is both a shareholder and 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. Mr Biggs also consents to the
inclusion in this report of the matters based on information in the form and
context in which it appears.
APPENDIX: JORC Code, 2012 Edition - Table 1 report template (references below may refer to the PDF version of this report)
Section 1 Sampling Techniques and Data
(Criteria in this section apply to all succeeding sections.)
Sampling techniques · Nature and quality of sampling (eg cut channels, random chips, or · Three (3) entities completed rock chip sampling methods over at
specific specialised industry standard measurement tools appropriate to the least four (4) separate surface sampling campaigns and are described in the
minerals under investigation, such as down hole gamma sondes, or handheld XRF current ASX Release, a generalised description of rock chip sample collection
instruments, etc). These examples should not be taken as limiting the broad is presented here.
meaning of sampling.
· Rock Chip Samples - were collected up to approximately a 5m
· Include reference to measures taken to ensure sample representivity radius around the recorded co-ordinate location. The rock chip fragments that
and the appropriate calibration of any measurement tools or systems used. were collected to make up the sample included a typical fragment size that
approximately ranged from 2-5cm.
· Aspects of the determination of mineralisation that are Material to
the Public Report. · Sub-sampling occurred as described in the section 'Sub-sampling
techniques and sample preparation' in Section 1 of the current Table 1.
· In cases where 'industry standard' work has been done this would be
relatively simple (eg 'reverse circulation drilling was used to obtain 1 m · The surface sample results described in this ASX Release are
samples from which 3 kg was pulverised to produce a 30 g charge for fire suitable for the reporting 'exploration results' for mineral prospectivity,
assay'). In other cases, more explanation may be required, such as where there additional exploration work would have to be completed to geologically model
is coarse gold that has inherent sampling problems. Unusual commodities or and then estimate a mineral resource.
mineralisation types (eg submarine nodules) may warrant disclosure of detailed
information.
Drilling techniques · Drill type (eg core, reverse circulation, open-hole hammer, · There are no historical drillholes in the Ayra -Sansa prospect
rotary air blast, auger, Bangka, sonic, etc) and details (eg core diameter, area.
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 recovery · Method of recording and assessing core and chip sample recoveries and · No new drillholes samples were taken.
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.
Logging · Whether core and chip samples have been geologically and · No geological logging took place as no new holes were drilled.
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.
Sub-sampling techniques and sample preparation · If core, whether cut or sawn and whether quarter, half or all core · All surface samples were collected dry.
taken.
· BHP Minerals rock chip samples -sample location and assay data
· If non-core, whether riffled, tube sampled, rotary split, etc and were extracted from an Appendix of the QDEX report using Optical Character
whether sampled wet or dry. Recognition, then underwent a correction or data QA/QC process to ensure that
subsequent data extracted was "as reported".
· For all sample types, the nature, quality and appropriateness of the
sample preparation technique. · Mount Isa Mines - the sample location and assay data were
extracted from QDEX report as .csv files.
· Quality control procedures adopted for all sub-sampling stages to
maximise representivity of samples. · Mount Isa Mines - Typically for surface samples there were brief
descriptions of the lithology etc is recorded within sample
· Measures taken to ensure that the sampling is representative of the ledgers/registers.
in situ material collected, including for instance results for field
duplicate/second-half sampling. · Mount Isa Metals - sample location and assay data were extracted
from an Appendix of the QDEX report using Optical Character Recognition, then
· Whether sample sizes are appropriate to the grain size of the underwent a correction or data QA/QC process to ensure that subsequent data
material being sampled. extracted was "as reported".
· The surface sample results described in this ASX Release are
suitable for the reporting 'exploration results' for mineral prospectivity,
additional exploration work would have to be completed to geologically model
and then estimate a mineral resource.
Quality of assay data and laboratory tests · The nature, quality and appropriateness of the assaying and · The rock chip samples were dispatched for Assay to Amdel
laboratory procedures used and whether the technique is considered partial or Analytical Laboratories at Mt Isa.
total.
· The samples were digested by Aqua Regia and elemental analysis
· For geophysical tools, spectrometers, handheld XRF instruments, etc, completed by Direct Optical Emission ICP: under Amdel Analytical Laboratory
the parameters used in determining the analysis including instrument make and test method IC3E.
model, reading times, calibrations factors applied and their derivation, etc.
· Elements analysed by this method IC3E included Cu, Pb, Zn, Ag,
· Nature of quality control procedures adopted (eg standards, blanks, As, Ba, Bi, Cd, Ci, Co, Fe, K, La, Mn, Mo, Na, Ni, Sn, Ta. Tl, and W. Not all
duplicates, external laboratory checks) and whether acceptable levels of batches, however, appear to have been analysed for all elements.
accuracy (ie lack of bias) and precision have been established.
· Mount Isa Mines rock chip samples: o Elements analysed by this
method could include Cu, Pb, Zn, Ag, As, Ba, Bi, Cd, Ci, Co, Fe, K, La, Mn,
Mo, Na, Ni, Sn, Ta. Tl, and W. Not all batches, however, appear to have been
analysed for all elements.
· Gold was assessed by sampling techniques in the field then
assayed by method GI 142 which is a cyanidation technique (BCL or Bulk Cyanide
Leach) bottle roll which had detection limits as low as 0.05 ppb Au.
· Rock chips were collected by taking a series of chips
approximately 2 to 5cm in diameter across approx. a 3m radius of the outcrop
being sampled. The sample was then crushed and analysed for a base metal suite
by method GA 140.
· Rock chips analysed for gold included for some batches suite GG
326 comprising of a 30-gram charged fire assay fusion with carbon rod finish
with detection limits down to 0.001 ppm Au. Some indicator element and whole
rock analysis was undertaken by ICP-MS at Analabs.
· The Analabs analytical methods changed from March 1994, yet the
same collection method appears to be comparable to earlier years:
· Analabs Assay methods employed for rock chip, soil, and stream
sediment additionally included (for some campaigns):
· Method GI 142 (ICP) for elements Cu, Pb, Zn, Fe, Mn, Co, P, &
As.
· Method GX401 (pressed powder XRF trace determination) for Ba; and
Method GG334 (aqua regia with carbon rod finish) for Au.
· Detection limits across any year were suitable for detecting
'Trace Elements'. 'Ore grade' testing occurred when either, visible base metal
minerals were present and/or were Cu, Pb, or Zn, exceeded 10,000ppm of the
respective element.
· Mt Isa Metals rock chip samples were processed at a Commercial
Laboratory, information in the QDEX report indicates that this was Analabs
Townsville (which later fell under SGS ownership). Elemental Analysis for the
assay results returned from the commercial laboratory were Cu, Pb, Zn, Ba, Co,
and Au. It is assumed that the analytical testing suite is comparable to those
reported for Mount Isa Mines Analabs suite.
Verification of sampling and assaying · The verification of significant intersections by either independent · Mount Isa Mines rock chip samples:
or alternative company personnel.
o Independent verification of surface samples had been completed for
· The use of twinned holes. selected gold assay values.
· Documentation of primary data, data entry procedures, data o Analabs Townsville Assays checked against ALS Townsville Assays when high
verification, data storage (physical and electronic) protocols. Au values were returned for stream sediment samples. The two sets of assay
results generally showed an acceptable correlation, and this matched
· Discuss any adjustment to assay data. observations historically reported by Mount Isa Mines.
· BHP Minerals and Mount Isa Metals rock chip samples do not appear
to have had any independent laboratory testing of the samples across different
laboratories.
· The surface sample results described in this ASX Release are
suitable for the reporting 'exploration results' for mineral prospectivity,
additional exploration work would have to be completed to geologically model
and then estimate a mineral resource.
Location of data points · Accuracy and quality of surveys used to locate drill holes (collar · For rock chip samples positions were recorded by handheld GPS
and down-hole surveys), trenches, mine workings and other locations used in with areas highlighting anomalies sometimes returned to for additional
Mineral Resource estimation. sampling and locations checked by handheld GPS.
· Specification of the grid system used. · Locational Data for BHP Minerals was in AMG66 and Mount Isa Mines
was recorded in local grid and/or AMG84 zone 54 Easting (mE) and Northing
· Quality and adequacy of topographic control. (mN). There was no topographical control used for some locations.
· Locational Data for Mount Isa Metals was recorded in local grid
and/or MGA94 zone 54 Easting (mE) and Northing (mN).
· The Arya rock chip sample dataset is anticipated on average to
have up to a +/-20m horizontal level of accuracy in sample locations and range
up to a +/-10m of accuracy in sample locations for vertical accuracy.
· Surface sample and assay data had been prepared and compiled into
Manifold GIS System and all data converted to GDA94-Zone 54.
Data spacing and distribution · Data spacing for reporting of Exploration Results. · For the Ayra surface sampling modelling for copper, the average
RMS sample-to-sample spacing was as follows:
· Whether the data spacing and distribution is sufficient to establish
the degree of geological and grade continuity appropriate for the Mineral o Stream sediments 67m
Resource and Ore Reserve estimation procedure(s) and classifications applied.
o Soil 48m
· Whether sample compositing has been applied.
o Rock chip 233m
Orientation of data in relation to geological structure · Whether the orientation of sampling achieves unbiased sampling of · In general, the strike of the Surprise Creek Formation is
possible structures and the extent to which this is known, considering the east-northeast to east, dipping moderately to the north.
deposit type.
· For 'Arya' rock chips there was no fixed orientation as these
· If the relationship between the drilling orientation and the methods were used in the first instance to define distinct areas of
orientation of key mineralised structures is considered to have introduced a anomalisms, based on areas of observed surface mineralisation.
sampling bias, this should be assessed and reported if material.
· For 'Arya' rock chips that produced significant anomalous values
appear to be associated with the mapped fault, fault bounded breccia, and the
Surprise Creek Formation 'PLrd' rock unit ('Prd' historical) that dominates
the 'Arya' prospect to the south of the fault.
Sample security · The measures taken to ensure sample security. · There is no detailed record of sample security methods were
employed in the field or by transport to the laboratory and measures taken in
the laboratory by earlier explorers.
· Given the provenance of the data from historical explorers and
the remoteness of the location, historical sample security is deemed adequate
for the reporting of surface assay grades and trends.
Audits or reviews · The results of any audits or reviews of sampling techniques and data. · No external reviews or audits have been undertaken, except for
the Independent Geologists Report by SRK in 2019 for the LSE Listing (see
reference below*).
*O'Reilly N., and Stock T., 2019, A Competent Persons Report on the Mineral
Assets of Castillo Copper Limited SRK Exploration Services Limited, Prepared
for Castillo Copper Prospectus, Cardiff, 169pp Oct 2019
Section 2 Reporting of Exploration Results
(Criteria listed in the preceding section also apply to this section.)
Mineral tenement and land tenure status · Type, reference name/number, location and ownership including · The following mineral tenures are held 100% by subsidiaries of
agreements or material issues with third parties such as joint ventures, Castillo Copper Limited, totalling an area of approximately 961km(2) in the
partnerships, overriding royalties, native title interests, historical sites, "Mt Oxide North project":
wilderness or national park and environmental settings.
· EPM 26574 (Valparaisa North) - encompasses the Big One historical
· The security of the tenure held at the time of reporting along with mineral resource, Holder Total Minerals Pty Ltd, granted 12-June-2018 for a
any known impediments to obtaining a licence to operate in the area. 5-year period over 100 sub-blocks (323.3Km2), Expires 11-June-2023.
· EPM 26462 (Big Oxide North) - encompasses the 'Boomerang'
historical mine and the 'Big One' historical mine, Holder: QLD Commodities Pty
Ltd, granted: 29-Aug-2017 for a 5-year period over 67 sub-blocks (216.5Km(2)),
Expires: 28-Aug-2022.
· EPM 26525 (Hill of Grace) - encompasses the Arya significant
aeromagnetic anomaly, Holder: Total Minerals Pty Ltd for a 5-year period over
38 sub-blocks (128.8Km2), Granted: 12-June 2018, Expires: 11-June-2023.
· EPM 26513 (Torpedo Creek/Alpha Project) - Granted 13-Aug 2018 for
a 5-year period over 23 sub-blocks (74.2Km2), Expires 12-Aug-2023; and
· EPM 27440 (The Wall) - An application was lodged on the
12-Dec2019 over 70 sub-blocks (~215Km(2)) by Castillo Copper Limited. The
tenure was granted on the 7(th) March 2021.
Exploration done by other parties · Acknowledgment and appraisal of exploration by other parties. · A selection of historical QDEX / mineral exploration reports has
been reviewed for historical tenures that cover or partially cover the Project
Area in this announcement. Federal and State Government reports supplement the
historical mineral exploration reporting (QDEX open file exploration records).
· Most explorers were searching for Cu-Au-U and/or Pb-Zn-Ag, and,
proving satellite deposit style extensions to the several small sub-economic
copper deposits (e.g., Big Oxide and Josephine).
· With the Mt Oxide Project in regional proximity to Mt Isa and
numerous historical and active mines, the Project area has seen the historical
mineral tenures subject to various styles of surface sampling, with selected
locations typically targeted at specific locations within the Mt Oxide Pillar
by shallow drilling (Total hole depth is typically less than 75m).
· The Mt Oxide project tenure package has a significant opportunity
to be reviewed and explored by modern exploration methods in a coherent
package of EPM's, with three of these forming a contiguous tenure package.
· Various Holders and related parties of the 'Big One' historical
mining tenure (ML8451) completed a range of mining activities and exploration
activities on what is now the 'Big One' prospect for EPM 26574. The following
unpublished work is acknowledged in previous ASX reports:
o West Australian Metals NL, 1994. Drill Programme at the "Big One" Copper
Deposit, North Queensland for West Australian Metals NL.
o Wilson, D., 2011. 'Big One' Copper Mine Lease 5481 Memorandum - dated 7
May 2011.
o Wilson, D., 2015. 'Big One' Mining Lease Memorandum - dated
o 25 May 2015: and
o Csar, M, 1996. Big One & Mt Storm Copper Deposits.
o Unpublished Xplore Resources field report Aug 2020.
· Arya prospect - the five (5) historical exploration reports
generated by various explorers that contributed information and data to this
ASX Release are detailed in the References section of the main body.
Geology · Deposit type, geological setting and style of mineralisation. · The Mt Oxide North project is located within the Mt Isa Inlier of
western Queensland, a large, exposed section of Proterozoic (2.5 billion- to
540-million-year-old) crustal rocks. The inlier records a long history of
tectonic evolution, now thought to be like that of the Broken Hill Block in
western New South Wales.
· The Mt Oxide project lies within the Mt Oxide Domain, straddling
the Lawn Hill Platform and Leichhardt River Fault Trough. The geology of the
tenement is principally comprised of rocks of the Surprise Creek and Quilalar
Formations which include feldspathic quartzites, conglomerates, arkosic grits,
shales, siltstones and minor dolomites and limestones.
· The Mt Oxide Pillar project area is cut by a major fault zone,
trending north-northeast to south-southwest across the permits. This fault is
associated with major folding, forming several tight syncline and anticline
structures along its length.
· The desktop studies commissioned by CCZ on the granted mineral
tenures described four main styles of mineralisation account for most mineral
resources within the rocks of the Mt Isa Province (after Withnall &
Cranfield, 2013).
· Sediment hosted silver-lead-zinc - occurs mainly within fine
grained sedimentary rocks of the Isa Super basin within the
· Western Fold Belt. Deposits include Black Star (Mount Isa PbZn),
Century, George Fisher North, George Fisher South (Hilton) and Lady Loretta
deposits.
· Brecciated sediment hosted copper - occurs dominantly within the
Leichhardt, Calvert, and Isa Super basin of the Western Fold Belt, hosted in
brecciated dolomitic, carbonaceous, and pyritic sediments or brecciated rocks
proximal to major fault/shear zones. Includes the Mount Isa copper orebodies
and the Esperanza/Mammoth mineralisation.
· Iron-oxide-copper-gold ("IOCG") - predominantly chalcopyrite,
pyrite magnetite/hematite mineralisation within high grade metamorphic rocks
of the Eastern Fold Belt. Deposits of this style include Ernest Henry,
Osborne, and Selwyn; and
· Broken Hill type silver-lead-zinc - occur within the high-grade
metamorphic rocks of the Eastern Fold Belt. Cannington is the major example,
but several smaller currently sub-economic deposits are known.
· Gold is primarily found associated with copper within the IOCG
deposits of the Eastern Fold Belt. However, a significant exception is noted
at Tick Hill where high grade gold mineralisation was produced, between 1991
and 1995 by Carpentaria Gold Pty Ltd, some 700 000 tonnes of ore was mined at
an average grade of 22.5 g/t Au, producing 15 900 kg Au. The Tick Hill deposit
style is poorly understood (Withnall & Cranfield, 2013).
· ROM Resources had noted in a series of recent reports for CCZ on
the granted tenures, that cover the known mineralisation styles including:
o Stratabound copper mineralisation within ferruginous sandstones and
siltstones of the Surprise Creek Formation.
o Disseminated copper associated with trachyte dykes.
o Copper-rich iron stones (possible IOCG) in E-W fault zones; and
o possible Mississippi Valley Type ("MVT") stockwork sulphide mineralisation
carrying anomalous copper-lead-zinc and silver.
· The Mt Oxide and Mt Gordon occurrences are thought to be breccia
and replacement zones with interconnecting faults. The Mt Gordon/Mammoth
deposit is hosted by brittle quartzites, and Esperanza by carbonaceous shales.
Mineralisation has been related to the Isan Orogeny (1,590 - 1,500 Ma).
· Mineralisation at all deposits is primarily
chalcopyrite-pyrite-chalcocite, typically as massive sulphide within breccias.
· At the Big One prospect, West Australian Metals NL described the
mineralisation as (as sourced from the document "West Australian Metals NL,
1994. Drill Programme at the "Big One" Copper Deposit, North Queensland for
West Australian Metals NL."):
o The targeted lode / mineralised dyke is observable on the surface. The
mineralisation targeted in the 1993 drilling programmed is a supergene copper
mineralisation that includes malachite, azurite, cuprite, and tenorite, all
associated with a NE trending fault (062(o) to 242(o)) that is intruded by a
porphyry dyke.
o The mineralised porphyry dyke is vertical to near vertical (85(o)), with
the 'true width' dimensions reaching up to 7m at surface. o At least 600m in
strike length, with strong Malachite staining observed along the entire strike
length, with historical open pits having targeted approximately 200m of this
strike. Exact depth of mining below the original ground surface is not clear
in the historical documents, given the pits are not battered it is anticipated
that excavations have reached 5m to 10m beneath the original ground surface.
o Associated with the porphyry dyke are zones of fractured and/or sheared
rock, the siltstones are described as brecciated, and sandstones around the
shear as carbonaceous.
o The known mineralisation from the exploration activities to date had
identified shallow supergene mineralisation, with a few drillholes targeting
deeper mineralisation in and around the 200m of strike historical open A
strongly altered hanging wall that contained malachite and cuprite nodules.
Chalcocite mineralization has been identified but it is unclear on the
prevalence of the Chalcocite; and the mineralisation was amenable to high
grade open pit mining methods of the oxide mineralization (as indicated by
numerous historical open pit shallow workings into the shear zone).
· Desktop studies commissioned by CCZ and completed by ROM
Resources and SRK Exploration have determined that the Big One prospect is
prospective for Cuco, and Ag.
· Desktop studies commissioned by CCZ have determined the Boomerang
prospect contains:
· Secondary copper staining over ~800m of strike length.
· Associated with a major east-west trending fault that juxtaposes
the upper Surprise Creek Formation sediments against both the underlying Bigie
Formation and the upper Quilalar Formation units.
· At the 'Flapjack' prospect there is the potential for:
o Skarn mineralisation for Cu-Au and/or Zn-Pb-Cu
from replacement carbonate mineralisation, particularly the Quilalar
Formation.
o Thermal Gold Auroele mineralisation is a potential model due to the high
silica alteration in thermal aureole with contact of A-Type Weberra Granite -
related to the Au mineralisation; and/or
o IOCG mineralisation related to chloride-rich fluids.
· At the 'Crescent' prospect there is the potential for:
o Skarn mineralisation for Cu-Au and/or Zn-Pb-Cu from replacement
carbonate mineralisation, particularly the Quilalar Formation; and/or
o Thermal Gold Auroele mineralisation is a potential model due to the high
silica alteration in thermal aureole with contact of A-Type Weberra Granite -
related to the Au mineralisation; and
o IOCG mineralisation related to potassic rich fluids.
· At the 'Arya' prospect there is the potential for:
o Supergene mineralisation forming at the surface along the fault, fault
breccia, and the Surprise Creek Formation 'PLrd' rock unit
o ('Prd' historical).
o Epigenetic replacement mineralisation for Cu (with minor components of
other base metals and gold) from replacement carbonate mineralisation,
particularly the Surprise Creek Formation.
o Skarn mineralisation for Cu-Au and/or Zn-Pb-Cu from replacement carbonate
mineralisation, particularly the Surprised Creek Formation; and/or
o IOCG mineralisation related to chloride-rich fluids.
· A selection of publicly available QDEX documents / historical
exploration reports have been reviewed, refer to sub-section "Further Work"
for both actions in progress and proposed future actions.
Drill hole Information · A summary of all information material to the understanding of the · There are no new drillholes completed, although fourteen (14) are
exploration results including a tabulation of the following information for planned for completion during Q2 2021. There is no historical drilling at Ayra
all Material drill holes: nor Sansa.
o easting and northing of the drill hole collar
o elevation or RL (Reduced Level - elevation above sea level in metres) of the
drill hole collar
o dip and azimuth of the hole
o down hole length and interception depth
o hole length.
· If the exclusion of this information is justified on the basis that
the information is not Material and this exclusion does not detract from the
understanding of the report, the Competent Person should clearly explain why
this is the case.
Data aggregation methods · In reporting Exploration Results, weighting averaging techniques, · No data aggregation methods are utilised in the current ASX
maximum and/or minimum grade truncations (eg cutting of high grades) and Release, since the sampling types are surface samples (for example: rock chip
cut-off grades are usually Material and should be stated. samples).
· 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 between mineralisation widths and intercept lengths · These relationships are particularly important in the reporting of · The strike of the country rock is northeast to east, with the
Exploration Results. deep Ayra conductor is orientated east - west. The smaller, shallower
conductors strike north-northeast to northeast (See Figure B1-1). The main
· If the geometry of the mineralisation with respect to the drill hole faulting trends is northeast.
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').
Diagrams · Appropriate maps and sections (with scales) and tabulations of · Appropriate diagrams are presented in the body and the Appendices
intercepts should be included for any significant discovery being reported of the current ASX Release. Where scales are absent from the diagram, grids
These should include, but not be limited to a plan view of drill hole collar have been included and clearly labelled to act as a scale for distance.
locations and appropriate sectional views.
· Maps and Plans presented in the current ASX Release are in MGA94
Zone 54, Eastings (mE), and Northing (mN), unless clearly labelled otherwise.
Balanced reporting · Where comprehensive reporting of all Exploration Results is not · All surface sampling and ground and airborne geophysical data has
practicable, representative reporting of both low and high grades and/or been reported, there have been no results withheld.
widths should be practiced to avoid misleading reporting of Exploration
Results.
Other substantive exploration data · Other exploration data, if meaningful and material, should be GEOTEM & PROTEM:
reported including (but not limited to): geological observations; geophysical
survey results; geochemical survey results; bulk samples - size and method of · The airborne electromagnetic GEOTEM geophysical survey undertaken
treatment; metallurgical test results; bulk density, groundwater, geotechnical by BHP Minerals in 1997 on historical tenure EPM11383 & EPM1152. A total
and rock characteristics; potential deleterious or contaminating substances. of 726-line kilometres were flown on a SE-NW, flown by 'Geoterrex-Dighem Pty
Limited' at a mean height of approximately 105m above the ground surface (line
spacing 500m apart). Previous interpretations the penetration of the GEOTEM
method to have an estimated range of between 200-300m below the ground
surface, this is dependent on conductivity contrasts, size, and attitude of
the subsurface targets. Eleven (11) anomalies were identified, with four (4)
recommended for follow up, with three (3) of the four (4) anomalies followed
up by ground geophysical at what CCZ calls the 'Arya' prospect. The BHP
Minerals 1997 GEOTEM survey information was extracted from QDEX Data to
accompany the QDEX report information.
· The 'Arya' prospect anomalies are EG01, EG02, EG10, with the
geophysical observations of the body and Appendices of the current ASX
Release, including the PROTEM observations. The PROTEM observations are
anticipated to have a deeper penetration than the GEOTEM observations, based
on the PROTEM loop, survey traverse, and/or depth sounding method applied.
Anomaly EG01 is also clearly evident on the AusAEM profile (Geoscience
Australia; Figure B2-2).
· QUESTEM & GENIE-EM: The airborne electromagnetic GEOTEM
geophysical survey undertaken by Mount Isa Mines in 1991 on historical tenure
EPM7448, EPM7338, and EPM7863 (see Figure B2-1). A total of approximately
600km-line kilometres (exact line length would need to be extracted from
digitised images) would were flown on a SE-NW, flown by 'Aerodata Holdings
Limited' at a mean height of approximately 120m above the ground surface (line
spacing 400m apart). In a previous ASX release (July 2020) Xplore Resources
Pty Ltd interprets the penetration of the QUESTEM method to have an estimated
range of between 200-300m below the ground surface, this is dependent on
conductivity contrasts, size, and attitude of the subsurface targets.
Twentynine (29) anomalies were identified across the three (3) historical
tenure, with six (6) recommended for follow up ground geophysical survey for
historical tenure EPM7448, and one of these L4 near the Arya prospect.
· Arya prospect anomaly L4 followed up by a ground electromagnetic
traverse by Mount Isa Mines GENIE-EM is to the west of the EG02 BHP minerals
anomaly.
· Queensland Government Data: 'PLrd' rock unit lower boundary from
the Surprise Creek Formation sourced from QSpatial and aligns with GeoResGlobe
- this is equivalent to the historical tenure reports 'Prd' rock unit lower
boundary from the Surprise Creek Formation.
Further work · The nature and scale of planned further work (eg tests for lateral · Further work will consist of a combination of:
extensions or depth extensions or large-scale step-out drilling).
o Fourteen (14) hole RC drilling Program (Table B2-1 and Figure B2-3,
· Diagrams clearly highlighting the areas of possible extensions, below).
including the main geological interpretations and future drilling areas,
provided this information is not commercially sensitive. o Soil and or Rock chip sampling
o Ground IP or EM Survey
TABLE B2-1: AYRA PROPOSED DRILLING DETAILS
BOREID X Y Z Total Azimuth Dip (Deg) TYPE
DEPTH (m) (Deg.)
AR01 353239.8 7865274.0 191.7 160 165 -60 RC
AR02 353258.1 7865418.7 189.0 160 135 -60 RC
AR03 352751.1 7865541.5 193.8 160 325 -60 RC
AR04 352774.6 7865583.3 191.5 160 120 -60 RC
AR05 352356.5 7865640.8 203.5 160 0 -90 RC
AR06 353574.3 7864723.5 195.8 160 0 -90 RC
AR07 353164.0 7865912.6 193.9 625 0 -90 RC
AR08 353109.1 7865721.9 187.5 625 0 -90 RC
AR09 353373.1 7865860.4 193.0 625 0 -90 RC
AR10 351930.5 7865891.7 243.1 160 270 -60 RC
AR11 352275.5 7865779.3 232.5 160 125 -60 RC
AR12 352103.0 7865742.8 238.8 160 125 -60 RC
AR13 352607.4 7865836.8 217.3 160 120 -60 RC
AR14 351776.3 7865653.9 206.0 160 290 -60 RC
This information is provided by RNS, the news service of the London Stock Exchange. RNS is approved by the Financial Conduct Authority to act as a Primary Information Provider in the United Kingdom. Terms and conditions relating to the use and distribution of this information may apply. For further information, please contact
rns@lseg.com (mailto:rns@lseg.com)
or visit
www.rns.com (http://www.rns.com/)
.
RNS may use your IP address to confirm compliance with the terms and conditions, to analyse how you engage with the information contained in this communication, and to share such analysis on an anonymised basis with others as part of our commercial services. For further information about how RNS and the London Stock Exchange use the personal data you provide us, please see our
Privacy Policy (https://www.lseg.com/privacy-and-cookie-policy)
. END UPDGZGMDMZDGMZZRecent news on Castillo Copper
See all newsREG - Castillo Copper Ltd - March 2024 Quarterly Activities Report
AnnouncementREG - Castillo Copper Ltd - Completion of Sale of Broken Hill Licenses
AnnouncementREG - Castillo Copper Ltd - Initial and Final Director’s Interest Notice
AnnouncementREG - Castillo Copper Ltd - Half-year Financial Report
AnnouncementREG - Castillo Copper Ltd - Board Changes
Announcement