Australia Opals

Figure 1 shows the typical cross-section of rock types hosting-opal mineralisation. To the right can be seen the line of the hollow, falling tectonic dislocation controlling the richest inclusions and lenses with opal mineralisation. On the radarogram (Figure 2) taken along the upper crest of the pit, the following can be clearly seen: a) lithologically heterogenous layers shown by notional colouring; b) tectonic disturbances in the form of slopping lines; c) entrance points of horizontal mine workings.