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THE TRUNDLE PROJECT
The Trundle project is located in the Junee-Narromine volcanic belt of the Macquarie Arc, and between the Northparkes mine, Australia’s second largest porphyry mine, and the Sunrise Energy Metals’ large, low cost, long life Sunrise development stage, battery materials complex which is in immediate proximity to the Platina scandium project (latter acquired by Rio Tinto in 2023).
In December 2023, Evolution Mining announced a A$720m acquisition for 80% of the Northparkes mine from CMOC. During 1H’2023, two neighbouring explorers undertook drilling at the western and southern extensions of the Trundle project and in 2H’2023 Northparkes undertook drilling at its regional E44 skarn deposit. FMG completed drilling immediately adjacent to the south, testing the potential southern extension and associated magnetic anomalies of the 3.2km mineralised and magnetic corridor Kincora drilled during the period of testing at the Dunn’s-NE Gold Zone-Botfield prospects at Trundle. Rimfire Pacific Mining completed a two rig program on the neighbouring western license, one drilling the Valley target adjacent to the northern section of the Trundle project, the other testing the western undercover extension of Kincora’s Mordialloc target.
Historically small base metal and gold occurrences were mined at the Trundle project with a combination of open cut and underground workings. Numerous groups have carried out mineral exploration over the last 40 years (the last prior to Kincora being Robert Friedland’s High Powered Exploration, a predecessor company to Ivanhoe Electric Inc (NYSE American: IE; TSX: IE), until the last commodity cycle downturn) focusing on porphyry copper-gold mineralisation associated with shoshonitic Ordovician igneous rocks like those at Goonumbla (Northparkes) and Cadia.
A total of 61,146m for 2208 holes of prior explorer drilling, mainly air-core, has taken place with over 90% of holes within 50m from surface. Extensive near surface mineralisation has been defined along a 10km north-south strike length with coincident (and largely untested) magnetic anomalies. Prior to Kincora only 11 holes have previously been drilled to depths greater than 250m.
Kincora has recognized that despite various positive indicators supporting deeper drilling that there had been a lack of drilling to intersect porphyry systems at depths similar to those at Cadia (>90Moz AuEq, host to five main porphyry and two skarn deposits), Northparkes (>24Moz AuEq, host to 22 porphyry discoveries, 9 of which have positive economics) and/or the more recent Boda-Kaiser discoveries (14.8Moz AuEq and growing).
For example, at the Trundle Park prospect, the average depth of previous explorer drilling was only 28 metres and defined a 700m gold-copper mineralised strike.
Kincora’s drilling has confirmed multiple intrusive complexes with hydrothermal systems at and adjacent to the Trundle Park prospect, across a 3.2km mineralised strike (open), from shallow depths, up to 900m wide (open) and vertical depth of greater than 800m.
Kincora’s approach has been to develop a detailed 3D model to advance and refine geological interpretations, to identify mineralised trends, then rank and test targets. A key advancement has been the development of this 3D working model, based upon the observed and updated geological logging, and also incorporating the structural, alteration, geochemical and mineralogical results, coupled with geophysical inversions. This significantly improved geological understanding and has both guided and justified deeper drilling.
This has resulted in three new discoveries to date by Kincora:
- Eastern Zone (Trundle Park) (2020):
- Hole TRDD001 (skarn with causative intrusion) intersecting 51m @ 1.17g/t Au, 0.54% Cu, including 8m @ 3.07g/t Au, 1.95% Cu
- Central Zone (Trundle Park) (2021):
- Hole TRDD022 (intrusion) intersecting 162m @ 0.24g/t Au, 0.04% Cu, including 18m @ 0.75g/t Au, 0.09% Cu
- Southern Extension Zone (SEZ, Trundle Park) (2021/22):
- Hole TRDD032 (skarn) intersecting 34m @ 1.45g/t Au, 0.25% Cu, including 2m @ 19.9g/t Au, 2.43% Cu
The porphyry intrusion and associated skarn system intersected at Trundle is a common geological setting of many large porphyry systems (eg Cadia, Grasberg, Ok Tedi etc). Within the Macquarie Arc, the Big and Little Cadia skarns at Cadia have produced an estimated 140,000t of high-grade copper (5-7%) and greater than 1.5Mt iron ore, and were important to the discovery of multiple adjacent causative intrusions and deposits that make up the largest porphyry system and gold mine in Australia.
In 2021/2022, a new copper-gold zone associated with an extensive skarn altered zone (calc-silicates along with magnetite and sulphides) was discovered and named the Southern Extension Zone (SEZ) at the Trundle Park prospect. The skarn system at the Trundle Park prospect is now currently believed to be one of, if not the, largest mineralised skarn systems in NSW, with the size of the skarn system providing significant encouragement for the likely presence of a causative copper-gold bearing porphyry source.
In 2022, detailed internal and external reviews took place on both the intrusive and skarn systems at Trundle Park. A key finding of the external review was that based on contact relations and textural observations, the skarn mineralisation at the Central and Eastern zones at Trundle Park are related temporally and genetically to a multi-stage intrusive complex of NE-striking, steeply NW-dipping, crowded monzodiorite porphyry dykes. The intrusive complex is hosted by a moderately (~40°) SW-dipping sequence of basaltic andesite to andesite volcanic and volcaniclastic rocks with locally thick, interbedded, calcareous sedimentary rocks and massive limestone.
At least three stages of monzodiorite porphyry intrusion were identified (eg in hole TRDD010), each associated with greater or lesser degrees of porphyry-style veining and associated hydrothermal alteration. Inter-mineral monzonite porphyry dykes are uncommon, but locally host highly anomalous gold mineralisation. Locally, the monzodiorite porphyries are cut by inter-mineral monzonite to syenite porphyries (including aplite dykes and vein dykes) and late-mineral quartz monzonite porphyries.
It was confirmed that proximal, dark brown garnet skarns lie adjacent to some of the intrusive contacts between the monzodiorite porphyry and calcareous wall-rock. Garnet-bearing endoskarn locally occurs within the monzodiorite porphyry which, together with the presence of early biotite and quartz veins in the same dykes, is considered to establish a temporal and genetic link between this proximal skarn and the monzodiorite porphyries. Two examples of previously unidentified causative intrusives were noted (i.e., from holes TRDD001 and TRDD015).
While geochronology is needed to confirm, the porphyry dyke swarm zone at the Central and Eastern zones exhibit many features of a zoned, multiple phase, moderately developed, porphyry intrusive system typical of the Macquarie Arc, but currently without an observed favourable structural environment sufficient to form an economic orebody (in part, adversely impacted by the skarn host).
Such intrusive systems have proven to often occur in clusters across large systems. The exploration approach and methodology applied by Kincora, enhanced by the 2022 review, have sought to be replicated at other prospects across the Trundle project.
Reviews have included existing down hole alteration and geochemical anomalies, but also at earlier stage nearer surface anomalies, seeking to identify (more) favourable lithology, alteration and geochemistry, and then in-turn systematically advance prospects exhibiting more well developed intrusive systems &/or favourable structural settings to greater depths than previous explorer drilling efforts and/or supported by untested geophysical anomalies.
Comparatively, it is noted that on the nearby and eastern portion of the Northparkes Igneous Complex that there have been 22 porphyry system discoveries to date and counting at Northparkes, interpreted to be the equivalent to Kincora’s discovery at the porphyry dyke swarm, “9 of which are currently economic”. It is worth noting “none of the major copper-gold systems (at Northparkes) have lateral geochemical footprints of greater than 500m” (November 2021 CODES Macquarie Arc conference – Jonathan Hoye presentation on Northparkes).
Across a significant fault to the Central and Eastern zones (which were the focus of the aforementioned external review) prograde and retrograde skarn alteration and mineralisation have been returned in all four holes to date within the SEZ (holes TRDD029-32), with no causative porphyry intrusive source yet confirmed. Ore grade gold-copper in skarn has been intersected within the SEZ over a 330m SSE strike and 225m W-E wide system, which is open, with drilling in 2023 extending this system across a major regional fault into the Botfield prospect. The intersected tabular, bedded and mineralised skarn system occurs along multiple horizons (with greater than 120m cumulative skarn widths in three of the four holes in the SEZ) which has assisted to provide various geological vectors for follow up drilling.
Post these reviews and before the most recent phase of drilling, Kincora had completed 34 diamond holes for 23,513m with a focus in the southern portion of the license at the Trundle Park prospect with 25 holes and 16,224m (up to 1,032m depth).
Kincora’s 2023 completed drilling program included 5 diamond holes for 1,972m testing four adjacent mineral systems. All holes have intersected zones of gold-copper mineralisation at shallow depths with broader lower grade intervals and localised higher grades, supporting the concept for a cluster or series of porphyry deposits.
Dunn’s North – hole TRDD035:
- 5m @ 2.77g/t gold from 77.5m, including 2m @ 14.2g/t gold
- First Kincora hole at the Dunn’s North prospect
- Multiple phase intrusive complex with porphyritic quartz-sulfide veins occurring in both near surface intrusive bodies and volcanic sandstone wall-rock
- Geophysical profile and target explained with original geological target failed to be tested and open
Dunn’s South – hole TRDD036:
- 4m @ 0.36g/t gold, 0.19% copper an 41ppm molybdenum from 52.5m, including:
- 6m @ 1.21g/t gold, 0.26% copper and 90ppm molybdenum from 65.9m
- 5m @ 0.50g/t gold, 0.79% copper and 180ppm molybdenum from 92.4m
- First Kincora hole at the Dunn’s South prospect
- Multiple phase intrusive complex with zones of higher gold-copper and molybdenum grades suggesting a proximal setting
- Geophysical profile and target explained with original geological target failed to be tested and open
North-East Gold Zone – TRDD038:
- 5m @ 0.23g/t gold, 0.02%, 10ppm molybdenum from 220.5m
- Step out hole returned the strongest and longest interval of potassic alteration with sulphides at the Trundle project
- Associated with both multiple phase intrusions and adjacent wall-rocks, molybdenum zone near end of hole
Botfield – hole TRDD037:
- First Kincora hole at the Botfield prospect and testing a regionally significant magnetic anomaly
- High grade veins and mineralised skarn from 112m and 330m vertical respectively:
- 9m @ 0.95% Cu, 0.62g/t Au (from 129-132m), including 0.9m @ 2.24% Cu, 1.75g/t Au
- 31m of magnetite skarn hosted anomalous gold and copper (from 393-424m)
- Working interpretation is the western portion of Botfield is an uplifted block (~500m) in comparison to the similar and adjacent magnetite skarn intervals at the SEZ discovery
Botfield – hole TRDD039:
- Follow up to TRDD037 stepping out 260m to the east.
- High grade veins and mineralised skarn from 80m and 240m vertical respectively:
- Strong hydrothermal hematite-silica alteration overprinting feldspar altered volcaniclastic conglomerate and coarse banded chalcopyrite-pyrite vein (from 92-94m) with 4m @ 0.17 g/t Au, 0.28% Cu
- ~40m of retrograde magnetite (massive) skarn with 25m @ 0.10g/t Au, 0.07% Cu (from 270m vertical depth), cut by carbonate-chalcopyrite veining at 288.6m downhole.
- Working interpretation is that the skarn system at Botfield continues towards and to surface to the east and is associated with historical informal workings on its most eastern limit
The causative porphyry source and fluid pathway is yet to be confirmed for the >900m NW-SE trending mineralised magnetic skarn intersected by Kincora drilling in the SEZ and Botfield prospects. Alteration and garnet zone zonation, coupled with metal tenure and the interpretation of regional structures supports an untested 750m N-S by 200m E-W corridor (named “The Gap”), and open further to the south, that remains prospective for causative porphyry intrusions and the source of the mineralisation in the skarns.
Assay results returned, and detailed geological logging of all holes from the 2023 program are suggestive of an interpreted proximal setting to the targeted porphyry intrusions. The observed alteration and mineralisation at each prospect drilled during this program are interpreted to be analogous to a proximal setting in comparison to the deposits at Northparkes and Cadia mines. This setting, coupled with the coincident magnetic response, across a long strike, and open both to the north and south, supports the Company’s concept that the southern portion of the Trundle project has the potential for a series or cluster of high-grade and gold endowed porphyry copper and skarn deposits.
Follow up air-core and diamond drill hole programs have been designed test open porphyry type mineralization at up to seven prospects, in the north to the south of the license:
- Existing prospect anomalous surface and down-hole gold-copper results occur with favorable geophysical features and lithology at Mordialloc NE, Mordialloc, Mordialloc South, Dunn’s North-Waynes, Dunn’s Central, Dunn’s South and The Gap (between Botfield and the SEZ) warranting diamond drill testing below target areas.
- To expand the geochemical foot print for copper-gold with favorable geophysical features and the search for intrusions through bedrock mapping by way of shallow (to basement) air core drilling at the Mordialloc South and Dunns North-Waynes’s target areas, in turn helping to focus deeper level drilling under anomalous areas.
Discussions with potential asset level partners are advancing as administration relating to the transfer of 100% ownership of the project to Kincora has just concluded (December 2023).