Introduction
A lot of work to discover and document Zn-Pb ore deposits has been done for 30 years in Silesia – Cracow region. Among well-recognised only few deposits such as Klucze or Zawiercie ‘I’ have fulfilled some conditions according to quality and resource criteria. Zn-Pb ore resources being exploited at the present (e.g. in Pomorzany mine or Trzebionka mine) have already been depleted in great part and it is predicted that mining activity will have been finished there by the year 2006. However, taking into account the economic aspects e.g. low prizes of metals and high prizes of production, it seems to be unprofitable to invest in building a new mine.
In the late 80’s detailed studies were carried out in the Zawiercie ‘I’ deposit. Collected data from the boreholes (PZ), mineralogical and chemical technology analyses, (Vrabetz, Ślusarek, 1993) as well as laboratory tests determining physical parameters of rocks such as density, porosity, consolidation and absorption capacity let the author determine and compare some physical features of Triassic and Devonian rock mass.