The Zn-Pb-Ag bodies are too numerous to list their dimensions in detail. As examples:
• 5 Orebody has a strike length of approximately 2000 metres, a width of up to 35m metres, and a vertical extent of approximately 1000 metres;
• 12 orebody has a length of approximately 1500m, a width of approximately 10 metres, and a vertical extent of approximately 1000 metres.
Pb-Zn-Ag orebodies at Mount Isa are broadly stratiform with a 60-65° westerly dip parallel to bedding in the host Urquhart Shale. The main stacked group of orebodies defines and en-echelon group of north-plunging lenses which are bounded to the south by the silica-dolomite alteration zone associated with the copper orebodies and to the north by the NNW-plunging Mount Isa Fold (Davis 2004).
The stratiform zone of Zn-Pb-Ag and pyrite enrichment within the Urquhart Shale is much more laterally extensive than the economically-defined orebodies (Painter, 2003), extending along stratigraphically consistent zones for more than 10km north of the economic limit of mineralisation.
Mount Isa’s stratiform silver-leadzinc sulphide mineralization occurs with pyrite and pyrrhotite in distinct bands dipping to the west, concordant with weakly bedded carbonaceous dolomitic sediments of the Urquhart Shale. The mineralization is intermittent through a stratigraphic interval of over 1 km, but the major orebodies are restricted to the upper 650 m. The orebodies occur in an echelon pattern, int ........
