Evolution Mining operates the wholly owned Mungari mine in Western Australia and holds a 51% interest in the East Kundana Joint Venture (EKJV), which includes the East Kundana deposits.
- subscription is required.
Summary:
The Mungari Operation lies within the Kalgoorlie Terrane of the Wiluna-Norseman Greenstone Belt, part of the greater Archaean Yilgarn Craton of Western Australia.
The geology is varied over the greater Mungari Operations project area and can be broken up into three broad geological camps being the:
• Kundana Gold Camp;
• Carbine Gold Camp; and
• Kunanalling Gold Camp.
The White Foil, Cutters Ridge and Frog’s Leg deposits are situated within the Norseman-Wiluna Greenstone Belt of the Yilgarn Craton, Western Australia. White Foil lies three kilometres to the west of the Zuleika Shear, a regional scale shear zone, and is hosted within a quartz rich gabbro unit which is part of the Powder Sill intrusive complex. The mineralised zone is 70m wide, 400m long and dips to the WSW and WNS at between 50° to 60° and is open at depth.
The Kundana deposits are hosted by a structurally prepared sequence of sediments, volcaniclastics, mafic and ultramafic volcanic and intrusive rocks typical of the greenstone sequences in the Archaean Yilgarn Block. The deposits are spatially associated with the craton-scale Zuleika Shear Zone. The Zuleika Shear Zone represents the boundary between the Coolgardie domain to the west and the Ora Banda domain to the east.
Lithologies at the Carbine-Zuleika Project consist of a series of feldspathic to quartzo-feldspathic tuffs intercalated with shales, siltstones, and sandstones. The Zuleika Shear Zone is the major structural element of the area. The two major mineralised planes in the Carbine area, the Carbine thrust and Lincancabur shear, host brecciated and laminated veins respectively, with high-grade gold mineralisation.
The Kunanalling project area covers the Kunanalling Shear Zone (KSZ) which is a trans-crustal feature separating the Coolgardie domain from the Ora Banda domain to the east. The Coolgardie domain comprises a folded sequence of metamorphosed tholeiitic, high magnesian, and komatiitic basalts with minor intercalated felsic to intermediate volcanic sediments. Gold mineralisation within the Kunanalling area is hosted by the Coolgardie Domain and is preferentially located in areas of high strain associated with the Zuleika and Kunanalling Shears.
The Zuleika Shear Zone, Kunnanalling Shear Zone and Carbine Thrust Zone are the dominant corridors of mineralisation at Mungari.
The Zuleika Shear Zone is the major structural element of the area and hosts two major mineralised shears (Strzelecki and K2 shears) with high-grade gold mineralisation hosted in laminated quartz veins.
The Carbine Thrust corridor intersects the Zuleika Shear in the north of the tenement package and hosts the Carbine thrust and Lincancabur Fault, defined by brecciated and laminated veins respectively, with high-grade gold mineralisation. The Carbine and Phantom deposits are associated with the Carbine Thrust, while the Paradigm deposit is hosted by the Lincancabur Fault. The Anthill deposit lies to the east of Paradigm on the Zuleika Shear and mineralisation is defined as stockwork veining in an altered pillow basalt.
The Kunanalling Shear Zone also hosts significant gold mineralisation with Cutters Ridge and Rayjax being mined recently and advanced projects including Castle Hill and Kintore.
Mineralisation and alteration models were constructed based on geological logging of drill holes and geological mapping. Mineralisation is characterised as orogenic, narrow vein gold deposits and, mineralised alteration envelopes, stockworks and mineralised intrusives and supergene enrichment horizons.
Orogenic, narrow vein gold mineralisation is typically hosted within brittle (extension vein arrays and breccias), brittle-ductile (laminated veins) and ductile (shear zones) structural zones and typically exhibit a sodic and potassic alteration assemblage, proximal to the structure. Alteration minerals include; sericite epidote, chlorite and albite, muscovite and biotite. Gold mineralisation is often observed in conjunction with sulphide crystals such as pyrite, pyrrhotite, arsenopyrite, galena and sphalerite. Visible gold has been observed in drill core and rock exposures.
The White Foil gold deposit is a quartz stockwork hosted in a gabbro. The gabbro is differentiated broadly into a quartz-rich phase in the west. This quartz gabbro unit is the most hydrothermally altered unit and contains the bulk of the gold mineralisation. The White Foil deposit is bounded to the west by hangingwall volcaniclastic rocks. To the east mineralisation becomes irregular and uneconomic in the more melanocratic phase of gabbro. Mineralisation is controlled by sheeted systems of stockwork veining, which has imparted strong alteration and sulphidation to the quartz gabbro.
The Frog’s Leg deposit is located in the southern portion of the Kundana mining area, within the Achaean Norseman-Wiluna greenstone belt of the Eastern Goldfields Province. The Kundana gold deposits are structurally related to the Zuleika Shear Zone, a regional NNW-trending shear zone that juxtaposes the Ora Banda domain to the east and the Coolgardie domain to the west. The Frog’s Leg deposit is located on the sheared contact between the porphyritic “cat rock” (regionally known as the Victorious Basalt) and volcaniclastic rocks of Black Flag Beds.
Mineralisation at Frog’s Leg is hosted within a number of steeply dipping NNW-SSE structures that are vertical or dipping steeply (~80 degrees) to the west. Surface and underground drilling intersect the mineralisation at an angle to minimise bias.