Jerdacuttup is located approximately 9km to the south of Kundip, comprising the 5.6Mt Trilogy polymettalic deposit. The tenure covers 400km² overlaying the Mt Barren sediments and Hatfield formation which are prospective for base and precious metals. Trilogy is hosted in Proterozoic rocks which overlay the Archean geology immediately south of Kundip.
• Located 25km SE of Ravensthorpe
• 19 strategically held tenements totalling 400km² over the Mt Barren Group & Hadfield formation prospective for SEDEX/VHMS deposits
• Trilogy polymettalic deposit (JORC) 2012: Au 162koz, Ag 9.7Moz, Cu 66kt, Pb 133kt, Zn 77kt
• Queen Sheba deposit (JORC 2004: Au 49koz)
• Bandalup Pools VHMS prospect with significant intercepts including:
∼ 36.3m @ 1.09% Zn, 1.07% Pb (inc. 5.4m @ 2.62% Zn, 2.31% Pb)
∼ 11.00m @ 0.93% Zn, 1.11% Pb (inc. 2.0m @ 2.46% Zn, 5.17% Pb)
∼ 28.0m @ 0.91% Zn, 0.47% Pb
ACH is currently undertaking Albion Process ™ bench scale testwork to optimise the recovery and payability of the A$2B in ground value contained within the polymettalic Trilogy ores (basis 2011 DFS at current metal and FX levels). Additionally, a regional exploration programme is underway to lever the substantial geochemical and geophysical databases into new discoveries.
The Company believes Jerdacuttup is prospective for multiple SEDEX/VHMS discoveries. Given the compelling nature of the opportunity, ACH is considering introducing a partner with the requisite technical and financial capability to realise the full potential of the Project.
Significant historical testwork and studies comprehensively demonstrate the technical merits of what is predominantly a base metal project (Cu/Zn/Pb) with significant precious metal credits. ACH has updated the historic resource estimate to be in accordance with JORC 2012 guidelines and is also progressing geophysical surveys along the Whoogarup Fault, a major region structure thought to be prospective for repetitions of Trilogy style mineralisation.
Trilogy has been interpreted as a sedimentary exhalative (SEDEX) style Au-Cu-Ag-Pb-Zn deposit hosted in Proterozoic aged graphitic siltstones. There are three parallel mineralised zones dipping broadly 40˚ to the SE, each typically 10m – 30m thick and separated by 5m – 30m of waste rock. Strike extent is over 320m, and down dip extent is over 300m.
Mineralisation is hosted in two main units:
~ Breccia of banded sulphide matrix and lithic fragments
~ Highly siliceous sedimentary breccia in the footwall of the mineralised zones
Two styles of economic mineralisation are evident:
~ Copper-gold only mineralisation, hosted mostly in late stage pyrite-chalcopyrite veining
~ Polymetallic (Au-Cu-Ag-Pb-Zn) mineralisation, which is also mineralised with the later stage Cu-Au veining
Near surface oxide mineralogy consists of covellite and lesser chalcocite replacing chalcopyrite, and anglesite replacing galena. Sulphide zone mineralogy consists of chalcopyrite, galena and lesser anglesite, and sphalerite. Oxidation is evident to about 40m below surface with some oxidation of chalcopyrite extending below the top of fresh rock.Queen Sheba Prospect which is located 2km southeast of Trilogy. The mineralisation is similar to Trilogy, but pyrite rather than base metal sulphide dominated.
The Mineral Resource for the Queen Sheba deposit was last reported by Tectonic geologists in September 2011. Data from both diamond and RC drillholes has been used in the resource calculation, with all RAB holes disregarded. The resource estimation was constrained by a lower cut-off grade of 1.0g/t Au, although some sub-grade intersections were included within the ore outline where determined appropriate.
Four geological domains were defined which primarily relate to the mineralised structures. A total resource (inferred) of 0.8 Mt @ 1.9 g/t, 3.98 g/t Ag was reported yielding approximately 50koz of gold. The structures defined remain open along strike and depth.