About 80 percent of the world's tin deposits occur
not as primary lodes, but as unconsolidated
secondary or placer deposits in river beds and
valleys or on the sea floor. The largest concentration
of both onshore and offshore placers is in the
extensive tin belt of South-East Asia, which
Major tin deposits are confined to a comparatively small number
of areas. More than half of the world's tin ore is mined in the
great Far Eastern tin field. There are also significant deposits in
South America.