Summary:
The Rebecca-Roe Gold Project comprises two distinct deposits: the Rebecca deposit and the Roe deposit, both project areas lie within the Shire of Kalgoorlie-Boulder and predominantly on the Yindi Pastoral Lease (Cowarna Downs Station).
Rebecca
Gold mineralisation along the Rebecca structural corridor extends over at least 1.8km strike and encompasses three major sub-parallel, moderate west dipping and north-south trending structures (Jennifer, Laura and Maddy). The lodes consist of disseminated sulphide/gold mineralisation within strongly foliated and locally silica altered and sheared gneiss up to 30m wide (true width), as well as multiple adjoining narrower stacked lodes of lower-grade mineralisation.
The geology at Rebecca features a folded sequence of gneiss, amphibolite and diorite. A 10m wide sub-vertical, NE-SW striking ultramafic dyke unit occurs in the northern half of Rebecca, cutting across the mineralisation.
The Duchess deposit occupies a broad area approximately 1.2km long and up to 900m wide, located approximately 4.5km south-west of Rebecca. The area is characterised by widespread sub-horizontal layers of mineralised material in the lower oxide profile, and multiple north trending and moderate west-dipping disseminated sulphide structures in underlying fresh granodiorite and micro-diorite gneiss.
The Duke deposit lies 1km to the south of Duchess in a north-west striking zone along the western limb of a project-wide fold. Mineralisation is steeply dipping and hosted in a single lode zone (10-25m wide), associated with moderate disseminated sulphides in weakly silicified felsic gneiss.
The Cleo deposit is located approximately 1.5km to the west of Rebecca. The local geology consists of a strongly folded sequence of diorites, amphibolites and metasediments that are cross-cut by steeply dipping (60-70°), narrow barren pegmatite veins. The main zone of mineralisation occurs as a broad (up to 30m wide), north trending, steeply west dipping (50-70°) lode within the diorite. There are a series of thinner (2-5m wide) north trending hanging wall and footwall lodes with westerly dips ranging from shallow to steep (25-65°).
The Duchess and Duke mineralised areas have local sub-cropping oxidised bedrock overlain by sandy and calcareous soils, while the 1.7km Rebecca mineralised corridor lies in an area of transported cover that is part of a local NE trending palaeo-drainage that trends diagonally from Duchess and into Lake Rebecca. Rebecca has up to 30m of transported cover on oxidised leached bedrock (saprolite), for a total 35-50m of unmineralised and/or depleted overlying material. The transported and oxide profile is generally unlithified below local hardpan caprock.
The Rebecca Project drill hole database is comprised of a combination of historic holes drilled by previous owners and recent RC and diamond drilling conducted by Ramelius. Drillholes at Rebecca are orientated orthogonal to the geological and mineralised trend. Intercept angles are often near perpendicular. Typically, as -60° east dipping holes drilling 40-50° west dipping lodes.
Roe
The greenstone geology of the Roe project area can be divided into the Yindi (Western) domain and the Edjudina (Eastern) domain. The Yindi Domain is centred around the ~60-70° Edipping Roe Shear Zone corridor. Lithology is dominated by mafic amphibolite, fine-to coarsegrained felsic-intermediate schists and turbiditic siltstone-shale.
The Edjudina domain is distinguished from the Yindi domain by major lithological, metamorphic and structural changes that occur across the interpreted western branch of the Claypan Shear Zone. A major lithological distinction is the presence of large volumes of high-Fe tholeiitic mafic rocks, mostly in the form of fractionated dolerite sills. The Bombora Sill is the largest of these bodies and hosts most of the gold mineralisation at Bombora. The main body of the Bombora Sill is 150-300m in true thickness at the centre of the project area, but magmatic and/or structural duplication creates a sill complex up to ~500m true thickness towards the southern end of the Resource area.
The Kopai-Crescent deposit is located approximately 2km to the north of Bombora on the northern extension of the eastern branch of the Claypan Shear Zone. The host rocks consist of an east-dipping package of mafic to intermediate volcanics, local metasediments and black shales, intruded by numerous, small bodies of dolerite (both fractionated and massive) and localised lamprophyres. The area is overlain by transported lake sediments which are typically 5 -10m thick. The weathering profile is generally shallow, with a stripped upper saprolite and a top of fresh rock surface located at ~35m depth.
Gold mineralisation at Bombora is largely stratabound, occurring preferentially in the ~150m thick, iron-rich granophyric quartz dolerite zone of the Bombora Sill over a 3km strike length. Mineralisation is hosted in three main lode orientations: (1) north-northwest-striking, sub-vertical steep lodes; (2) gently north- to northeast-dipping flat lodes and (3) moderately west-dipping west lodes.
The mineralisation in controlled in two ways:
• Lithological control: where structures intersect the competent, magnetite-rich quartz dolerite. Mineralisation occurs via the sulphidation process, with the dominant alteration assemblage identified as silica-albite-pyrrhotite. These shoots have a southern shoot plunge.
• Structural control: at the intersection of multiple structures. When the intersection involves a west-dipping structure the primary alteration assemblage of silica-albite-pyrrhotite is overprinted by carbonate-biotite-pyrite. This control gives a gentle north plunging orientation to the shoots, equivalent to the orientation of sigma two in the stress ellipsoid. This control is mainly observed in the quartz dolerite, where the structures are better developed, but is also observed outside of the quartz dolerite.
The Bombora deposit is totally concealed under a thin (5 to 15m) layer of transported cover developed within and peripheral to the Lake Roe Salt Lake system. The transported cover is dominated by lacustrine clays, overlain by aeolian sands and transported ferricrete adjacent to the lake footprint. The in-situ regolith profile is strongly stripped, with the upper saprolite rarely preserved in the deposit area.
The Roe database is comprised of a combination of historic RC and diamond drilling combined with recent drilling conducted by Ramelius. At Bombora, drill holes are on a nominal spacing of 40m x 20m with areas at a 20m x 20m spacing completed every 200 metres along strike in the shallow part of the Bombora resource to ~200-250 meters below surface). At Claypan, the drill spacing is on a nominal 200m x 80m reconnaissance pattern. At Kopai-Crescent, the drill spacing is on a nominal 100m x 40m with local infill to 40m x 20m in the southern (Crescent) area and within the Indicated Resource areas.