The Jamieson project is located on unrestricted crown land within the Mt Useful Slate Belt geological province. The region was founded on gold mining in the 1850s and a number of gold mines have operated or are currently in production in the region. Carawine is advancing two main prospect areas at the Jamieson Project: Hill 800 and Rhyolite Creek.
Hill 800 is the most advanced prospect, with drilling to date returning outstanding widths and grades of gold and copper mineralisation, e.g. 93m @ 3.22g/t Au from 2m, including 31m @ 6.64g/t Au from 58m (H8DD006) (refer ASX announcement 27 May 2019). Around Hill 800 five near-surface gold targets have been generated, each with characteristics similar to the mineralisation at Hill 800.
The Rhyolite Creek prospect is about five kilometres south of Hill 800 and comprises two potential large-tonnage, low-grade gold-copper targets and one high grade seafloor-position VHMS gold and base-metal target.
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 over 19 diamond drill holes 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 Plan View
The main zone of mineralisation has a northeast strike and a dip that rotates from steep in the south to moderate in the north and is increasing in strike, width and grade with depth where it remains open. Drilling to date has intersected mineralisation over more than 170m in strike length, with an estimated true width ranging from 23m to 47m (average 35m), extending from surface to over 175m down-dip.
Mineralisation is associated with intense silica-sericite-pyrite-gold (SSP) alteration from surface, surrounding a stockwork of coarse gold and chalcopyrite stringer veins developed from around 100m below surface. 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
Future drilling will target the down-dip extensions of mineralisation below the current limit of drilling, before targeting nearby magnetic anomalies for potential porphyry systems beneath and adjacent to the deposit.
Hill 800 Porphyry Copper-Gold Relationship
After identifying five new prospects in the vicinity of Hill 800, each with elements suggesting an association with magmatic mineral systems, an analysis of multi-element lithogeochemical data collected from Carawine's diamond drill holes at Hill 800 by Dr Scott Halley from Mineral Mapping Pty Ltd was completed. Dr Halley's study provided a number of key outcomes lining the mineralisation at Hill 800 with a porphyry copper-gold source, as follows:
Schematic diagram showing the pathfinder geochemical and alteration patterns of a typical porphyry copper-gold mineral system and the relative location of Hill 800 (modified from Halley et.al, 2015).
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.
Hill 800 cross-Section showing alteration zones and pathfinder elements
The geochemical evidence strongly supports the interpretation of the mineralisation at Hill 800 being sourced from, and related to, a fertile copper-gold porphyry intrusion at some distance from the deposit (refer ASX announcement 11 September 2019).
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 and selected drill intervals
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. The target VMS horizon remains open to the south, with potential for the mineralised horizon to thicken either there, or within the current drill pattern to the north.
Both areas have had only limited follow-up drilling and as such are targets for drill testing.
In addition to Hill 800 and Rhyolite Creek several prospects have been identified from one, or a combination, of surface mapping, rock chip sampling, soil geochemistry and detailed geophysical surveys. Most are associated with distinct magnetic high anomalies, representing targets for potential porphyry copper-gold mineral systems.
Detailed heli-mag survey image and contours of RTP magnetics, note magnetic high anomalies
Five targets are within 1km of Hill 800 and have elements identical to those associated with outcropping mineralisation at Hill 800, as well as sitting above a magnetic high complex:
Significantly, the new prospects are all above a large regionally distinct magnetic high and zoned geochemical anomalies, indicating these prospects and the Hill 800 deposit have the potential to be part of a larger scale, sub-volcanic intrusive driven mineral system. A similar association of near-surface mineralisation and geochemical anomalism above a magnetic high is seen at Rhyolite Creek, 5km south of Hill 800 (refer ASX announcements 15 July & 3 December 2019).
Hill 800 prospect area magnetic anomaly complex, note several discrete magnetic high anomalies
These regional targets will be advanced with 3-dimensional modelling of those targets associated with magnetic highs to determine an accurate location, size and depth of the source of each magnetic anomaly, in addition to surface mapping and geochemical sampling. This information will be used to prioritise each target for drill testing.
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.