Stavely Minerals Ltd (ASX: SVY)
Geological Model: Beyond the assay results, which are borderline economic, the combination of mineralisation and alteration observed points to the signature of the outer “ring” of a porphyry intrusion.
Mineralisation is associated with epidote alteration, indicating a possible inner- propylitic position, while quartz veins display ‘pinking’ on the margins, likely a potassic feldspar selvedge to the veins, indicating a more proximal outer- potassic signature (see Sillitoe model, next page). The near-proximal indication of inner propylitic to outer-potassic alteration is considered very encouraging as this zone is typically lower-grade and would indicate that the target higher grade potassic core is likely close by meaning that the overall position of the economic mineralisation is close to surface.
As the Cayley Lode shows strong similarities to the Butte and Magma lode-style porphyry mineral system, Toora West could present similarities with the Anaconda/Pittsmont and Resolution porphyry intrusions.
The 15km distance between the Cayley Lode and the Toora West Prospect appears too large to have a direct metallogenic link between the two zones. But more importantly, the type of alteration observed indicates that the potential porphyry intrusion is close to surface, while the Resolution mineralisation is much deeper, starting at 2km depth.
