The Jamieson project, located 20km east of the Jamieson township in northeast Victoria, is the most-advanced of the Company’s project portfolio. The Jamieson 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. The project comprises granted exploration licence EL5523, covering an area of 34 km2 which is dominated by Cambrian-aged volcanic rocks considered similar in age, depositional style and setting to the Mt Read Volcanic belt in western Tasmania – host to a number of world-class gold and base metal deposits.
Two main prospects have been identified at the Jamieson project to date, these are Hill 800 and Rhyolite Creek.
Hill 800 was discovered by New Holland Mining NL in 1994, with drilling beneath outcropping gold-rich gossans identifying high-grade gold mineralisation. The prospect is a volcanic-hosted massive sulphide (VHMS) gold-copper (Au-Cu) system with similar host rock, age and mineralisation style to the 1.5Moz Henty gold deposit, and Hellyer lead-zinc-silver-gold deposits in Western Tasmania. Carawine's maiden drilling program - the first drilling program in almost a decade at Hill 800 - was completed during May and June, 2018.
The program comprised 14 diamond core holes drilled for a total of 2,376m and successfully defined the style and orientation of gold mineralisation whilst also exploring the system’s strike and depth extents. Assay results from the program exceeded the Company’s expectations, including the following outstanding assay intervals:
Footwall Stringer Zone
(downhole widths may not represent true width, see ASX announcements dated 7 June, 25 June, 6 August and 20 August 2018 for details)
Results from the drilling program also enabled development of a significant new interpretation of the geometry and orientation of the mineralised system at Hill 800, with three distinctly mineralised zones identified as the “800,” “740” and “Footwall Stringer” Zones.
Hill 800 3-D Interpretation (long projection looking towards the west)
800 and 740 Zones
The 800 and 740 Zones are outcropping, coherent bodies of gold mineralisation characterised by intense silica-sericite-pyrite alteration. These zones are elongate along a north-northeast strike with a low dip to the south-southwest and are stacked against the steep, northeast trending Prelude Fault. The low-angle southwest dipping NSX Fault separates the two zones. Preliminary interpretation suggests there has been preferential mineralisation of the more permeable volcaniclastic units in zones 800 and 740, which are interlayered with less-permeable andesitic lavas, resulting in the mineralisation geometries observed.
Approximate dimensions of the 800 Zone from drilling to date are 240m long x 80m wide x 50m high, with mineralisation closed by drilling and outcrop. Approximate dimensions of the 740 Zone are 270m long x 75m wide x 50m high, with mineralisation remaining open along strike to the northeast.
Further repetitions of the 800 and 740 Zones are possible, either as stacked lenses or as faulted offsets by additional structures similar to the NSX Fault, stepping downwards to the north. Future drilling will target these while also exploring the open extents of the mineralised zones identified to date.
The Footwall Stringer Zone sits below and to the west of the 800 and 740 Zones, on the opposite side of the Prelude Fault to the 740 and 800 Zones. This zone is characterised by gold and copper mineralisation hosted by a network of centimetre-scale pyrite and chalcopyrite “stringer” veins within chlorite-altered, brecciated andesite and basalt lavas. Overall the zone strikes north to northeast, with a moderate dip to the east into the Prelude Fault. Coarse gold is observed within quartz-chlorite-chalcopyrite-pyrite veins and stringers and within the selvedges to these veins. This zone is defined to date by three drill holes, having been intersected over about 150m along strike, about 80m down dip, with a true width of about 25m. It remains open in all directions with potential for significant strike and depth extensions and these will be targeted in the next phase of drilling.
Gold at Hill 800 is associated with intense silica-sericite-pyrite alteration in the 800 and 740 zones. In the Footwall stringer zone, gold and copper mineralisation is associated with chalcopyrite and pyrite, and as coarse gold grains.
Hill 800 mineralisation: Visible gold in the Footwall Stringer zone (H8DD002, 203.9m down-hole) (above), and silica-sericite-pyrite alteration within the 92.7m @ 3.22g/t Au interval in H8DD006 (below)
Further details of Hill 800 are available in Carawine's ASX announcement dated 20 August 2018.
There are several other prospects within the Jamieson project, the most advanced of which is Rhyolite Creek. The prospect is about 5km south of Hill 800 with work by previous explorers identifying three targets for follow-up exploration: two potential large tonnage, low grade gold targets and one potential seafloor-position VHMS gold and base metal target.
The VHMS target at Rhyolite Creek is a zinc-gold-silver horizon at the contact of felsic (above) and intermediate volcanics (below), intersected in diamond hole RCD001 drilled by previous explorers in 2008. RCD001 targeted a linear magnetic anomaly in an area of gold-silver-base metal anomalism in surface geochemical samples, intersecting variably altered volcaniclastic sediment, rhyolite and andesite, including a zone of strong alteration and massive sulphide mineralisation which returned an interval of:
(see the Company’s IPO Prospectus released on 12 December 2017 for details)
Re-sampling of core within this interval, from 223.5 to 224.5m returned assay values of 20.3% Zn, 1.5% Pb, 0.7% Cu, 178g/t Ag and 10.3g/t Au.
Rhyolite Creek cross-section through RCD001 and RCD002
The zinc mineralisation was identified as being related to low-iron sphalerite and the footwall to this high-grade zone was reported as being strongly altered intermediate volcanics, with significantly elevated zinc values over 52m downhole. Carawine believes the high-grade zinc-gold-silver horizon intersected in RCD001 is potentially associated with a VHMS seafloor or sub-seafloor deposit, occurring at the contact of intermediate and felsic volcanic sequences, with wide zones of footwall alteration and anomalism. Additional holes drilled by previous explorers have intersected this position over a strike length of about 400m, remaining open along strike. Further details can be found in the Company’s IPO Prospectus released on 12 December 2017.
Rhyolite Creek prospect area with historic surface gold and copper anomalism and selected drill intervals
The second target style at Rhyolite Creek is gold mineralisation in the felsic volcanic sequence (rhyolite lavas and volcaniclastic sediments) and was the focus of previous explorers up until the mid-2000s. Two areas have been identified as requiring follow-work: the Zig Zag Track, 500m southwest of RCD001, and; the Jamieson River South area about 1km southeast of RCD001.
At the Zig Zag Track area, brecciated rhyolite and fragmented epiclastic units with massive sulphides adjacent to a “silica knob” outcrop in two holes yielded the following results (re-calculated from historic data):
At the Jamieson River South area Hole RCK002 intersected near surface gold mineralisation:
(downhole widths may not represent true width, for details refer to the Company’s IPO Prospectus released on 12 December 2017)
Both areas have had only limited follow-up drilling and as such are targets for future drilling.
The discovery to date of two VHMS-style systems on the tenement confirms the outstanding potential of the Jamieson Project. Typically, deposits of this style occur in clusters often defining significant mining camps. Gold-rich VHMS deposits are particularly attractive given their high-grade and polymetallic nature. The Jamieson Project area is considered to be under-explored, with limited systematic exploration for VHMS deposits completed to date, representing an excellent opportunity for Carawine to realise the potential of the area with future work.