West Desert Zn-Cu Deposit
The property is underlain by a sequence of Paleozoic dolostones with lesser, generally thin-bedded limestones and minor interbedded quartzites and shales. These have been offset by the Juab fault, a west-northwesterly trending, northerly dipping normal fault that trends through the middle of the property. A late Eocene quartz monzonite intrusive complex underlies a large part of the property at depth but is not exposed at surface. In the vicinity of the WD deposit, it rises to the bedrock surface in a cupola which subcrops below shallow Pleistocene gravels.
The WD deposit consists of sphalerite with lesser chalcopyrite occurring in skarn developed in thin-bedded, shale rich carbonate rocks proximal to the intrusive complex. Magnetite is very abundant and often massive. Carbonate rocks peripheral to the skarn and intrusive complex have been converted to marble.
The WD deposit occurs in two principal zones separated by the Juab fault, the shallower Main zone being situated in Ordovician carbonate rocks north of the fault and the CRD (Deep) zone in similar rocks of Cambrian age to the south. Sphalerite, the zinc bearing mineral in both zones, is generally medium to coarse-grained. Chalcopyrite, the copper bearing mineral, occurs in both zones and also in areas where it is the dominant mineral. The overall abundance of pyrite and other iron sulphides such as pyrrhotite in the West Desert system is very low. The Main zone has been oxidized to an average depth of about 250 metres.
Indium is present in significant quantities in the WD deposit. Initial petrography and energy dispersive X-ray (EDX) analysis has shown that it is present essentially only in sphalerite as a lattice substitution in amounts as high as an exceptional 8% by weight.
Mineralization in the Main zone has been traced with drilling over a length of about 525 metres, a width of about 150 metres and to a depth of 575 metres and remains open to the west and to depth. A number of separate mineralized horizons comprising the CRD (Deep) zone have been traced with drilling over an area of about 330 metres by 225 metres at depths of between about 450 to 750 metres. They remain open to the west, south, and east.