Abstract

"There are two types of deposits: (1) In the vicinity of Rooiberg village, cassiterite ore bodies were formed by replacement within a stratigraphically defined, orthoclase-rich arkosite horizon. Petrofabric analyses helped to establish a system of shear and tension fractures that served as channelways for the oreforming solutions emanating from the granite. Insignificant metal values only have been located in these fractures. The mineral paragenesis of the pockets is dominated by tourmaline, cassiterite, carbonates, and a variety of sulfides (pyrrhotite, pyrite, chalcopyrite, bismuthinite, sphalerite, galena). (2) In the Leeuwpoort area, a number of cassiterite lodes are mined. Detailed analysis of the complex structural pattern revealed the presence of two fracture systems: The A-system is slightly older than the B-system. Their origin is ascribed to two couples approximately perpendicular to each other with the intruding granite as principal force. Fractures of both systems have

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