The Jamieson Project is located on unrestricted crown land within the Mt Useful Slate Belt geological province. The region was founded on gold in the 1850s, with several historic and currently operating gold mines. The project comprises granted exploration licences EL5523 and EL6622, covering Ordovician and Silurian aged sediments and Cambrian age volcanic rocks in the Mt Useful Slate Belt geological province. The focus of Carawine’s work is the “window” of Cambrian volcanic rocks known as the “Jamieson Volcanics”.
Carawine has identified two main prospect areas at the Jamieson Project: Hill 800 and Rhyolite Creek, and is regionally searching for porphyry-related gold-copper mineralisation. The Company is considering its options for advancing the Jamieson project tenements while it focusses on its Western Australian projects, including advancing exploration in its own right, or investigating opportunities to divest the project.
Jamieson Project location plan
The Mt Useful Slate Belt within the Melbourne Zone is located in the Lachlan Fold Belt of southeastern Australia. The Jamieson project covers a window of Cambrian-aged volcanic rocks known as the Jamieson Volcanics, which together with the Stavely Volcanics are the only Cambrian-aged, calc-alkaline volcanic belts in Victoria and therefore share similar settings for their formation and evolution. This link is further supported by tectonic reconstructions of eastern Gondwanaland which join the Mt Stavely Volcanics with the Jamieson Volcanics and the Mt Read Volcanics in Tasmania at the time of their formation/deposition (refer ASX announcement 16 October 2019).
The association of the Jamieson Volcanics with the Mt Stavely Volcanics and the Mt Read Volcanics (a well-established, major metallogenic region of Australia), is considered to significantly add to the prospectivity of Carawine’s Jamieson Project to host significant mineral deposits.
Lachlan Fold Belt, southeastern Australia
Hill 800 was discovered by New Holland Mining NL in 1994, with drilling beneath outcropping gold-rich gossans identifying high-grade gold mineralisation. Carawine’s maiden diamond drilling program was completed in June 2018, with outstanding assay results exceeding the Company’s expectations of both the width and grade of gold mineralisation and confirming Hill 800 as the Company's most advanced prospect within the Jamieson Project.
To date the Company has completed a number of drilling campaigns at Hill 800, returning outstanding widths and grades of gold and copper mineralisation from intensely altered volcanics, including:
Hill 800 long projection in the plane of mineralisation, looking southeast.
Hill 800 cross section A-A'
The main zone of mineralisation has a northeast strike and a dip that rotates from steep in the south to moderate in the north. It is defined in drilling over a 170m strike length, with an estimated true width ranging from 23m to 47m (average 35m), extending from surface to over 300m down-dip and importantly, remains open down dip and to the south.
Mineralisation is associated with intense silica-sericite-pyrite (SSP) altered rhyodacite in a broad, lower-grade zone, and high-grade vein array shoots comprising chalcopyrite-pyrite-quartz veins and chalcopyrite-pyrite veinlets, with narrow sericite vein selvedges in chlorite-altered andesite. Recent drilling has defined one of these vein array shoots extending for at least 150m down-dip and remaining open, containing individual 1m samples ranging from 13.7g/t Au (HEC47) up to 148g/t Au (H8DD022) and 0.4% Cu (H8DD022) up to 2.1% Cu (HED1) - highlighting exceptionally high gold and copper grades and a nuggety nature (refer ASX announcement 14 May 2020).
Petrographic work indicates gold within the SSP alteration of the main zone occurs within fractures and on the boundaries of pyrite grains. In the stringer veins gold occurs as free, coarse grains.
Hill 800 mineralisation styles
Porphyry-Related Mineralisation and Targets
In September 2019 the Company established the potential for gold and copper mineralisation at its Hill 800 prospect to be related to a copper-gold porphyry system, based on an analysis of multi-element geochemical data and the recognition of an alteration pattern typical of porphyry mineral systems (refer ASX announcements 11 September and 16 October 2019). This followed the identification of several new prospects around Hill 800 with strong magmatic / porphyry geochemical signatures, and the recognition of two broad but distinct regional-scale magnetic anomalies at Hill 800 and Rhyolite Creek (refer ASX announcement 15 July 2019). The key outcomes of the study (completed by Dr. Scott Halley) linking the mineralisation at Hill 800 with a porphyry copper-gold source are as follows:
Schematic diagram showing typical porphyry copper-gold mineral system pathfinder geochemical and alteration patterns relative to observations at Hill 800 (refer ASX announcement 11 September 2019).
The geochemical data also defines an alteration pattern at Hill 800 which is typical of porphyry mineral systems. Proximal to and associated with the main mineralised zone at Hill 800, the intense silica-sericite (paragonite)-pyrite alteration has a geochemical signature consistent with phyllic alteration. Associated with lower gold grades and more distal to the main mineralised zone, moderate sericite-chlorite alteration has a geochemical signature consistent with propylitic alteration. For further details of Dr Halley's findings refer to ASX announcement dated 11 September 2019.
The Company's deepest drill hole at Hill 800 H8DD025 returned elevated concentrations of the porphyry pathfinder elements selenium (Se) and tellurium (Te) with a corresponding drop in bismuth (Bi) concentration. This may indicate a transition from the upper parts of the porphyry alteration system to the mid-levels, vectoring towards a potential copper-gold porphyry source at depth.
Regionally the targeting of potential porphyry systems has been advanced with the completion of a detailed helicopter-borne magnetic and radiometric (“heli-mag”) geophysical survey over the Jamieson Volcanics (refer ASX announcement 3 December 2019). Typical copper-gold porphyries can display a magnetic “potassic zone” at the core of the system which can result in a magnetic response comprising a magnetic high surrounded by a magnetic low. Where the system is more complex, multiple intrusions and/or structural disruption can result in more complex magnetic responses. Magnetic anomaly complexes therefore provide excellent drill targets for copper-gold porphyry systems.
Detailed heli-mag survey image and contours of RTP magnetics and magnetic anomaly complex targets.
Analysis and 3D modelling of the heli-mag survey data identified fourteen anomalies around Hill 800 and the surrounding area, and two anomalies at Rhyolite Creek. From these, seven anomalies are prioritised for initial drill testing based on their size, depth, and location relative to known mineralisation and surface geochemical anomalism. These are anomalies M2 to M5 and M14 in the Hill 800 area, and M15 & M16 at Rhyolite Creek (refer ASX announcement 29 January 2020).
Drill testing of these anomalies has commenced, with drill hole H8DD023 targeting the M14 and M2 anomalies intersecting altered volcanics with very high magnetic susceptibility readings (from magnetite), boxworks after sulphide, and the presence of quartz, chlorite, epidote, calcite and actinolite with intensities consistent with hydrothermal propylitic alteration. The style of alteration is consistent with the outer alteration zone of a mineralised porphyry system (refer ASX announcement 9 March 2021).
These results are considered encouraging in the context of the Company’s copper-gold porphyry exploration model, returning alteration assemblages and geochemical vectors consistent with the exploration model.
The Rhyolite Creek prospect is about five kilometres south of Hill 800 and comprises three distinct targets which require follow-up drilling: two potential large-tonnage, low-grade gold-copper targets and one seafloor-position VHMS gold and base-metal target. At surface, the prospect is defined by an extensive gold and copper soil anomaly in rhyolitic rocks and as with Hill 800, sits directly above a significant regionally anomalous magnetic high. This suggests, as with Hill 800, a potential magmatic input or control on the shallower, near-surface mineralisation.
Rhyolite Creek prospect area with historic surface gold and copper anomalism, selected drill intervals and magnetic anomaly targets
Historic drilling of the gold and copper soil anomaly is limited but has produced encouraging results including:
The mineralisation in these drill holes is reported as being associated with brecciated rhyolite and fragmented epiclastic rocks, and provides an excellent target for follow-up drilling to understand the style of mineralisation and explore for extensions and/or higher grades.
Stratigraphically below the main anomaly, historic drill hole RCD001 intersected a high grade zinc-gold-silver horizon at the contact between andesite (below) and rhyolite (above), representing a classic seafloor volcanogenic massive sulphide (VMS) mineralised position:
The footwall to this high-grade zone was reported as being strongly altered intermediate volcanics, with significantly elevated zinc values over more than 50m downhole width, containing several individual 1m assay values of 1.1% to 2.5% Zn, e.g. 59m @ 0.5% Zn from 228m (refer ASX announcement 12 December 2017).
Rhyolite Creek cross-section through RCD001 and RCD002
Follow-up drilling by previous explorers intersected the horizon up to 400m to the north of RCD001, intersecting significant zinc anomalism (e.g. 4.2m @ 2.2% Zn, 0.55g/t Au, 9.75g/t Ag in drill hole RCD004) but without repeating the high grades in RCD001 suggesting the potential for a large system.
Drill hole RCDD006 was recently completed by Carawine as an initial test of this horizon approximately 80m to the south of historic drill hole RCD001, and the two magnetic anomalies M15 and M16 as potential porphyry source targets. The drill hole returned 1m @ 1.45 Zn from 255m within the prospective zinc horizon, above a broad zone of anomalous zinc with an interval of 32m @ 0.40% Zn from 309m, in strongly altered andesitic volcaniclastics. Between 270m and 305m downhole a magnetic, porphyritic intermediate intrusion appears to have stoped out the mineralised andesite volcaniclastic unit and much of the prospective horizon, as also occurred in historic drill hole RCD002. There is an additional highly magnetic porphyritic intermediate intrusive further up-hole, and together these are interpreted to be the likely sources of the M15 and M16 magnetic anomalies.
The mineralisation intersected in RCDD006 is associated with white sphalerite and traces of chalcopyrite within sheared silica-sericite-pyrite (“SSP”) altered andesitic volcaniclastics, occurring as stringer veins and disseminated blebs throughout. Several shear zones were recorded throughout the andesitic units, particularly between 300m and 375m depth, with intense SSP alteration associated with the shear foliation. Above the zinc horizon are flow-banded rhyolite lava, volcaniclastic pumice breccia, sandstones and siltstones of rhyolitic composition.
Rhyolite Creek prospect zinc anomaly and drill hole plan.
Despite the low zinc grades in RCDD006, the potential for significant zinc mineralisation at Rhyolite Creek remains strong, with the mineralised horizon intersected in 4 widely spaced drill holes over 400m along strike, dipping approximately 10 degrees to the west, and cropping out 600m further east from RCDD006 where it is associated with a >300ppm zinc soil anomaly. Drilling to date remains very broadly spaced, therefore the mineralised horizon remains largely untested (refer ASX announcement 17 May 2021).
Drill hole RCDD006 is just the first hole drilled by Carawine at the Rhyolite Creek prospect, with further work including drilling required to test the potential of the prospect for zinc, gold and copper mineralisation.
Please note: these pages include information that relates to Exploration Results prepared and first disclosed under the JORC Code (2012). The information was extracted from the Company’s previous ASX Announcements which can be viewed in the Investor Information & News section of this website by clicking here.