Thorium as a guide to potentially tin-bearing placer deposits

Considerable difficulty is experienced in prospecting for tin placer deposits and several ideas have been put forward in the past to help the prospector in his task. During the present study, a 'typical' mineral suite associated with cassiterite has been compiled from the literature. It can clearly be seen that the thorium-rich minerals zircon, monazite and xenotime are commonly associated with cassiterite-bearing placer deposits. A pilot study in the Thabazimbi area showed a distinct positive relation between tin and thorium. Further work elsewhere in the Waterberg Group, however, has shown no relation, since no significant quantities of tin are present. It is nervertheless suggested that thorium anomalies may be used as a guide to finding cassiterite-bearing placer deposits