·      Type, reference name/number, location and ownership including agreements or material issues with third parties such as joint ventures, partnerships, overriding royalties, native title interests, historical sites, wilderness or national park and environmental settings.

·      The security of the tenure held at the time of reporting along with any known impediments to obtaining a licence to operate in the area.

EL 8434 is located about 28km east of Broken Hill whilst EL 8435 is 16km east of Broken Hill.  Both tenures are approximately 900km northwest of Sydney in far western New South Wales (Figure A1-2-1). 

EL 8434 and EL 8435 were both granted on the 2^{nd of} June 2016 to Squadron Resources for a term of five (5) years for Group One Minerals.  On the 25^{th of} May 2020, Squadron Resources changed its name to Wyloo Metals Pty Ltd (Wyloo).  In December 2020 the tenure was transferred from Wyloo Metals to Broken Hill Alliance Pty Ltd a 100% subsidiary company of Castillo Copper Limited.  Both tenures were renewed on the 12^{th of} August 2021 for a further six (6) years and are due to expire on the 2^{nd of} June 2027.

EL 8434 lies across two (2) 1:100,000 geology map sheets Redan 7233 and Taltingan 7234, and two (2) 1:250,000 geology map sheets, SI54-3 Menindee, and SH54-15 Broken Hill in the county of Yancowinna.  EL 8434 consists of one hundred and eighty-six (186) units) in the Adelaide and Broken Hill 1:1,000,000 Blocks covering an area of approximately 580km².

EL 8435 is located on the 1:100,000 geology map sheet Taltingan 7234, and the 1:250,000 geology map sheet SH/54-15 Broken Hill in the county of Yancowinna.  EL 8435 consists of twenty-two (22) units (Table 1) in the Broken Hill 1:1,000,000 Blocks covering an area of approximately 68km².

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 the 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 C-2).

Figure C-2:  EL 8434 and EL 8435 General Location Map

·      Acknowledgment and appraisal of exploration by other parties.

Explorers who were actively involved over longer historical periods in various parts of EL8434 were: - North Broken Hill Ltd, CRAE 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.  Depth of 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 subcrops 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 dominantly 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 data base.  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.

·      Deposit type, geological setting, and style of mineralisation.

Regional Geology

The Broken Hill polymetallic deposits are located within Curnamona Province (Willyama Super group) (Figure C-3) that hosts several world-class deposits of lead, zinc, silver, and copper.  The Willyama Supergroup consists of highly deformed metasedimentary schists and gneisses with abundant quartz-feldspathic gneisses, lesser basic gneisses, and minor 'lode' rocks which are quartz-albite and calc-silicate rocks (Geoscience Australia, 2019).  Prograde metamorphism ranges from andalusite through sillimanite to granulite grade (Stevens, Barnes, Brown, Stroud, & Willis, 1988).

Regionally, the tenures are situated in Broken Hill spatial domain which extends from far western New South Wales into eastern South Australia.  The Broken Hill Domain hosts several major fault systems and shear zones, which were formed by various deformation events and widespread metamorphism which has affected the Willyama Supergroup (Figure C-4). 

Major faults in the region include the Mundi Mundi Fault to the west of Broken Hill, the Mulculca Fault to the east, and the Redan Fault to the south. Broken Hill is also surrounded by extensive shear zones including the Stephens Creek, Globe-Vauxhall, Rupee, Pine Creek, Albert, and Thackaringa-Pinnacles Shear Zones.

Figure C-3:  Regional Stratigraphy

Modified after: (Stevens, Barnes, Brown, Stroud, & Willis, 1988)

Figure C-4:  Regional Geological Map

Modified after (Peljo, 2003)

Local Geology

There are over twenty (20) rock formations mapped within the project area.  Parts of the project area are covered by Quaternary alluvium, sands, and by Tertiary laterite obscuring the basement geology.  Within the Lower to Middle Proterozoic Willyama Supergroup (previously Complex) there are two (2) groups, the Thackaringa Group, and the younger Broken Hill Group (Colquhoun, et al., 2019).  A summary of the units that host or appear to host the various mineralisation styles within EL 8434 and EL 8435 is given below.

Broken Hill Group

The Hores Gneiss is mostly comprised of quartz-feldspar-biotite-garnet gneiss, interpreted as metadacite with some minor metasediments noted.  An age range from Zircon dating has been reported as 1682-1695Ma (Geoscience Australia, 2019).  The Allendale Metasediments unit contains mostly metasedimentary rocks, dominated by albitic, pelitic to psammitic composite gneiss, including garnet-bearing feldspathic composite gneiss, sporadic basic gneiss, and quartz-gahnite rock.  Calc-silicate bodies can be found at the base of the unit and the formation's average age is 1691 Ma (Geoscience Australia, 2019).

Thackaringa Group

The Thorndale Composite Gneiss is distinguished by mostly gneiss, but also migmatite, amphibolite, and minor magnetite.  The age of this unit is >1700Ma (Geoscience Australia, 2019) and is one of the oldest formations in the Group.  The Cues Formation is interpreted as a deformed sill-like granite, including Potosi-type gneiss.  Other rock-types include pelitic paragneiss, containing cordierite.  The average age: ca 1700-1730 Ma. (Stevens, Barnes, Brown, Stroud, & Willis, 1988).  Other rock types include mainly psammo-pelitic to psammitic composite gneisses or metasedimentary rocks, and intercalated bodies of basic gneiss.  This unit is characterised by stratiform horizons of granular garnet-quartz +/-magnetite rocks, quartz-iron oxide/sulphide rocks and quartz-magnetite rocks (Geoscience Australia, 2019).  This is a significant formation as it hosts the Pinnacles Ag-Pb-Zn massive sulphide deposit along with widespread Fe-rich stratiform horizons. 

The protolith was probably sandy marine shelf sedimentary rocks.  An intrusion under shallow cover was syn-depositional.  The contained leuco-gneisses and Potosi-type gneisses are believed to represent a felsic volcanic or volcaniclastic protolith.  Basic gneisses occur in a substantial continuous interval in the middle sections of the Formation, underlain by thinner, less continuous bodies.  They are moderately Fe-rich (abundant orthopyroxene or garnet) and finely layered, in places with pale feldspar-rich layers, and are associated with medium-grained quartz-feldspar-biotite-garnet gneiss or rock which occurs in thin bodies or pods ('Potosi-type' gneiss). 

A distinctive leucocratic quartz-microcline-albite(-garnet) gneiss (interpreted as meta-rhyolite) occurs as thin, continuous, and extensive horizons, in several areas.  The sulphide-bearing rocks may be lateral equivalents of, or associates of Broken Hill type stratiform mineralisation.  Minor layered garnet-epidote-quartz calc-silicate rocks occur locally within the middle to basal section.  The unit is overlain by the Himalaya Formation. 

The Cues Formation is intruded by Alma Granite (Geoscience Australia, 2019).  The Himalaya Formation (Figure C-6) consists of medium-grained saccharoidal leucocratic psammitic and albitic meta-sedimentary rocks (average age 1700Ma).  The unit comprises variably interbedded albite-quartz rich rocks, composite gneiss, basic gneiss, horizons of thinly bedded quartz-magnetite rock.

Pyrite-rich rocks occur at the base of the formation (Geoscience Australia, 2019).  It is overlain by the Allendale Metasediments (Broken Hill Group).  The Himalaya Formation hosts cobalt-rich pyritic horizons at Pyrite Hill and Big Hill.  The protolith is probably sandy marine shelf sedimentary rocks with variable evaporitic or hypersaline component.  Plagioclase-quartz rocks are well-bedded (beds 20 - 30mm thick), with rare scour-and-fill and cross-bedded structures. 

Thin to thick (0.5 - 10m) horizons of thinly bedded quartz-magnetite rock also occur with the plagioclase-quartz rocks.  In some areas the formation consists of thin interbeds of plagioclase-quartz rocks within meta-sedimentary rocks or metasedimentary composite gneiss (Geoscience Australia, 2019).  Lady Brassey Formation which is well-to-poorly-bedded leucocratic sodic plagioclase-quartz rock, as massive units or as thick to thin interbeds within psammitic to pelitic metasedimentary composite gneisses.  A substantial conformable basic gneiss.  It overlies both Mulculca Formation and Thorndale Composite Gneiss.  Part of the formation was formerly referred to as Farmcote Gneiss in the Redan geophysical zone of Broken Hill Domain - a zone in which the stratigraphy has been revised to create the new Rantyga Group (Redan and Ednas Gneisses, Mulculca Formation, and the now formalised Farmcote Gneiss).

Lady Louise Suite

This unit is approximately 1.69Ma in age comprising amphibolite, quartz-bearing, locally differentiated to hornblende granite, intrusive sills, and dykes, metamorphosed, and deformed; metabasalt with pillows (Geoscience Australia, 2019).  Annadale Metadolerite is basic gneisses, which includes intervening metasedimentary rocks possibly dolerite (Geoscience Australia, 2021).

Rantya Group

Farmcote Gneiss contains metasedimentary rocks and gneiss and is a new unit at the top of Rantyga Group.  It is overlain by the Cues Formation and Thackaringa Group, and it overlies the Mulculca Formation.  The age of the unit is between 1602 to 1710Ma.  Mulculca Formation is abundant metasedimentary composite gneiss, variable sodic plagioclase-quartz-magnetite rock, quartz-albite-magnetite gneiss, minor quartz-magnetite rock common, minor basic gneiss, albite-hornblende-quartz rock (Geoscience Australia, 2019).  Ednas Gneiss contains quartz-albite-magnetite gneiss, sodic plagioclase-quartz-magnetite rock, minor albite-hornblende-quartz rock, minor quartzo-feldspathic composite gneiss.  It is overlain by Mulculca Formation.

Silver City Suite

Formerly mapped in the Thackaringa Group this new grouping accommodates the metamorphosed and deformed granites.  A metagranite containing quartz-feldspar-biotite gneiss with variable garnet, sillimanite, and muscovite, even-grained to megacrystic, elongate parallel to enclosing stratigraphy. It occurs as sills and intrudes both the Thackeringa Group and the Broken Hill Group.  This unit is aged between 1680 to 1707Ma.

Torrowangee Group

Mulcatcha Formation comprises flaggy, quartzose sandstone with lenticular boulder and arkosic sandstone beds.  Yangalla Formation contains boulder beds, lenticular interbedded siltstone, and sandstone.  It overlies the Mulcatcha Formation (Geoscience Australia, 2020).

Sundown Group

The Sundown Group contains Interbedded pelite, psammopelitic and psammitic metasedimentary rocks and it overlies the Broken Hill Group.  The unit age is from 1665 to 1692Ma (Figure C-5).

There is also an unnamed amphibolite in Willyama Supergroup, which present typically medium grained plagioclase and amphibole or pyroxene rich stratiform or discordant dykes.

Figure C-5:  EL 8434 and EL 8435 Solid Geology

·      A summary of all information material to the understanding of the exploration results including a tabulation of the following information for all Material drill holes:

o  easting and northing of the drill hole collar

o  elevation or RL (Reduced Level - elevation above sea level in metres) of the drill hole collar

o  dip and azimuth of the hole

o  down hole length and interception depth

o  hole length.

·      If the exclusion of this information is justified on the basis that the information is not Material and this exclusion does not detract from the understanding of the report, the Competent Person should clearly explain why this is the case.

Proposed new drilling has not started yet.

·      In reporting Exploration Results, weighting averaging techniques, maximum and/or minimum grade truncations (e.g., cutting of high grades) and cut-off grades are usually Material and should be stated.

·      Where aggregate intercepts incorporate short lengths of high-grade results and longer lengths of low-grade results, the procedure used for such aggregation should be stated and some typical examples of such aggregations should be shown in detail.

·      The assumptions used for any reporting of metal equivalent values should be clearly stated.

·      No metal equivalents have been reported. Rare earth element results have been converted to rare earth oxides as per standard industry practice (Castillo Copper 2022f).

·      No compositing of assay results has taken place, but rather menu options within the Datamine GDB module have been used to create fixed length 1m assay intervals from the original sampling lengths.

·      The rules follow very similarly to those used by the Leapfrog software in creating fixed length samples.

·      These relationships are particularly important in the reporting of Exploration Results.

·      If the geometry of the mineralisation with respect to the drill hole angle is known, its nature should be reported.

·      If it is not known and only the down hole lengths are reported, there should be a clear statement to this effect (e.g. 'down hole length, true width not known').

·      A database of all the historical borehole sampling has been compiled and validated. It is uncertain if there is a strong relationship between the surface sample anomalies to any subsurface anomalous intersections due to the possible masking by variable Quaternary and Tertiary overburden that varies in depth from 0-40m.

·      As the strata is tightly folded, the intersected cobalt-rich layers are overstated in terms of apparent thickness, however the software calculates a true, vertical thickness.

·      Mineralisation is commonly associated 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-rich layers have a north-northwest to north strike.

·      Appropriate maps and sections (with scales) and tabulations of intercepts should be included for any significant discovery being reported These should include, but not be limited to a plan view of drill hole collar locations and appropriate sectional views.

·      Current surface anomalies are shown on maps released on the ASX (Castillo Copper 2022a and 2022b).  All historical surface sampling has had their coordinates converted to MGA94, Zone 54.

·      Where comprehensive reporting of all Exploration Results is not practicable, representative reporting of both low and high grades and/or widths should be practiced to avoid misleading reporting of Exploration Results.

·      All recent laboratory analytical results have been recently reported (see Castillo Copper 2022a, b, c, d, e, and f) for assay results.

·      Regarding the surface and sampling, no results other than duplicates, blanks or reference standard assays have been omitted.

·      Other exploration data, if meaningful and material, should be reported including (but not limited to): geological observations; geophysical survey results; geochemical survey results; bulk samples - size and method of treatment; metallurgical test results; bulk density, groundwater, geotechnical and rock characteristics; potential deleterious or contaminating substances.

·      Historical explorers have also conducted airborne and ground gravity, magnetic, EM, and IP resistivity surveys over parts of the tenure area but this is yet to be fully georeferenced (especially the ground IP surveys). Squadron Resources conducted an airborne EM survey in 2017 that covers Iron Blow and The Sisters, but not the southern prospects.