PACE Theme 2 (drilling partnerships with PIRSA and industry): Year 4 partnership DPY4-09, Dominion JV area magmatic nickel-copper-PGE mineral prospects. Project final report.
Created: 29 Oct 2024 Revised: 07 Dec 2024

The Dominion-Mithril joint venture project area comprises five Exploration Licences presently held 100% by Dominion Mining. Mithril's share of exploration performed to date has focussed on ELs 3270 and 3044, which are considered by the company to...

The Dominion-Mithril joint venture project area comprises five Exploration Licences presently held 100% by Dominion Mining. Mithril's share of exploration performed to date has focussed on ELs 3270 and 3044, which are considered by the company to be prospective for nickel-copper sulphide mineralisation. The area of interest within the Dominion Mining tenements covers approximately 1600 square km, and is interpreted by Mithril to be the northern extension of the Fowler Domain. The targeted mineralisation styles are those of the Thompson Nickel Belt massive sulphide deposits, which are associated with deformed ultramafic pods, with the mineralisation later remobilised into structural traps, and/or massive sulphide deposits of the Voisey's Bay type, which occur in feeder pipes which existed between magma chambers and the former land surface. Outcropping mafic and ultramafic basement rocks are known to occur throughout the JV area as mafic dykes and lamprophyres, which are possibly co-genetic and may be related to the Neoproterozoic Gairdner Dyke Swarm intrusive event. In addition, numerous mafic and ultramafic buried basement lithology intercepts have been recorded on previous drillhole stratigraphic logs, including gabbro, peridotite, lherzolite, norite, and pyroxenite. The most significant of these is the Aristarchus ultramafic intrusion which was drilled by PIRSA, because it contains minor nickel-copper sulphides. The age and emplacement relationships between these mafic and ultramafic rocks are unknown, although the results of costeaning, mapping and drilling undertaken by previous company explorers and PIRSA over the Aristarchus and Blackfellow Hill bodies do suggest that these rocks were intruded as dykes, probably in a period long after the cessation of upper amphibolite-granulite facies metamorphism that affected their host rocks. The PIRSA Aristarchus 1 ultramafic drill core displays intrusive contacts with the host gneiss/foliated granite, and the undeformed nature of this ultramafic rock suggests it intruded post-metamorphism. Furthermore, a trench excavated in the Aristarchus prospect area by Pacific Exploration Consultants in the early 1980s showed that a west-dipping ultramafic dyke at least 50 m thick was intruded into felsic schist. The Fowler Domain is a broad curvilinear belt of anastomosing shear zones which may have facilitated the intrusion and extrusion of mafic-ultramafic rocks. The correlation between the Fowler Domain and Canada's Thompson Nickel Belt has been well documented by PIRSA. Although basement exposure in the Fowler Domain is poor, evidence suggests that both areas have experienced similar geological histories and importantly, both contain mafic and ultramafic bodies although, in the Thompson Nickel Belt, these are deformed. The potential for discovering Voisey's Bay type massive sulphide deposits in the Fowler Domain has been less well canvassed, however, the apparently undeformed nature of the Aristarchus ultramafic intrusion is more characteristic of a Voisey's Bay type deposit than of a Thompson Nickel Belt type deposit. In follow-up to a number of regolith nickel and copper geochemical anomalies revealed by historic surface sampling and shallow drilling, Mithril drilled and assayed 62 new aircore holes and also re-sampled former Dominion Mining calcrete sampling holes to establish robust anomalies that could be further refined by ground EM surveying. This geophysical work, carried out in October 2006 and March 2007, profiled 22 lines totalling 30.2 line km and identified six locations showing varying quality shallow basement EM responses, three of which gave a good correlation with aeromagnetic anomalies. The buried conductive bodies with the perceived highest exploration priority (Area 1 - Aristarchus prospect) were drill tested during May-July 2007 as one of PIRSA's PACE Initiative Year 4 approved drilling subsidy projects. Three inclined NQ diamond core holes were completed for a total penetration of 873 m (including 287 m of percussion precollars). The drilling rates were slowed by badly broken ground, but all of the holes achieved their programmed depths. Although two of the holes do not appear to have encountered their targeted conductors, it is considered likely that drillhole DMDD-002 did. This interpretation should be confirmed shortly by the conduct of a downhole EM survey. Significant magmatic sulphides (including pentlandite) were intersected in hole DMDD-002 over a narrow depth interval, to give an assay result of 0.45 m @ 0.16% Ni and 230 ppb Pt+Pd. These sulphides are hosted by a meta-peridotite. The presence of magmatic sulphides and an apparent absence to date downhole of any other conductive rock types (such as graphitic gneiss) has given Mithril confidence to continue exploration on this prospect, starting with the acquisition of downhole EM data from each of the three PACE drillholes. It is hoped that a significant off-hole conductive target can be generated by doing this work. There are a number of other regional ground EM and geochemical anomalies, associated with second and third-order magnetic anomalies interpreted to be sourced by buried mafic / ultramafic intrusive bodies, that as yet remain untested within the JV area. Given the positive results seen so far, it is anticipated that further work will soon be conducted on these areas.

More +

About this record

Record No mesac21800
Topic Geoscientific Information
Type of Resource Document
Category Type
Document Type Mineral Company Report - Mineral Exploration
Contributor Pontifex and Associates Pty Ltd
Sponsor
Tenement
Tenement Holder Dominion Gold Operations Pty Ltd;Mithril Resources Ltd
Operator Mithril Resources Ltd
Geological Province Gawler Craton
Mine Name Aristarchus prospect
Stratigraphy
Commodity
Notes
Notes: PACE project code DPY4-09 : company final submission includes exploration drilling actual total cost ($236,374.00 excluding Goods and Services Tax), out of which PACE Initiative funds have paid $50,000.00 (excl. GST).
Geographic Locality:...

Notes: PACE project code DPY4-09 : company final submission includes exploration drilling actual total cost ($236,374.00 excluding Goods and Services Tax), out of which PACE Initiative funds have paid $50,000.00 (excl. GST). Geographic Locality: Mulgathing Antiform;Aristarchus Rise;Blackfellow Hill;Mount Christie;Woomera Prohibited Area Doc No: Env 11447 Drillhole: DMDD001;(234167);DMDD002;(234168);DMDD003;(234169);DMAC001 - DMAC062;(352474 - 352535) Drillhole Unit No: 5637 01650;5637 01651;5637 01652

More +

Language English
Metadata Standard ISO 19115-3

Citations

Use constraints License
License Creative Commons Attribution 4.0
Persistent identifier https://pid.sarig.sa.gov.au/document/mesac21800
Citation McKinnon-Matthews, J.;Purvis, A.C.;Pontifex, I.R. PACE Theme 2 (drilling partnerships with PIRSA and industry): Year 4 partnership DPY4-09, Dominion JV area magmatic nickel-copper-PGE mineral prospects. Project final report. Mineral Company Report - Mineral Exploration
https://pid.sarig.sa.gov.au/document/mesac21800

Technical information

Status
Maintenance and Update Frequency
Geographic Reference GDA2020 (EPSG:7844)
Geo bounding box {"type":"Polygon","coordinates":[[[133.251362,-30.581792],[133.901351,-30.581792],[133.901351,-29.74855],[133.251362,-29.74855],[133.251362,-30.581792]]]}
Purpose

                    
                    

                    
                  
Lineage