Several tin deposits on the West Coast of Tasmania are associated with massive sulfides (pyrrhotite and pyrite). Past and present major producers include Mt. Bischoff, and Renison Bell and Cleveland.A detailed study of the deposits at Cleveland Mine reveals the strong influence of structural controls on the sulfide-cassiterite mineralization, even though the deposits have a stratiform nature. The major structure in the mine area is the steeply inclined and overturned southeastern limb of a subhorizontal anticline located to the immediate NW of the mine. The limb structure has been intensely deformed by thrust faulting along the axial plane direction such that the Lode Bed (host rock) occurs as a series of subvertical lenses, en echelon and increasing in depth to the SE. The period of intense deformation is correlated with the Tabberabberan orogeny (upper Devonian). The Cleveland deposit is interpreted as representing a metasomatic replacement of finely layered calcareous shales and shaly limestone (the Lode Bed of Hall's Formation: Cambrian (?) System) by mineralizing solutions associated with a late acid igneous phase of the Tabberabberan orogeny.