Chapter 12 Metallic mineral deposits

Abstract

This account concentrates on the the primary metallic mineral deposits and occurrences in Sumatra, in particular the recent discoveries of gold, tin and base metals. The residual and placer deposits are given less emphasis, as no significant discoveries have been made in recent years.The history of mineral exploration and discovery in Indonesia has been reviewed recently by van Leeuwen (1993, 1994), documenting the change in emphasis of mineral-based activities from western to eastern Indonesia since the World War II. These studies bring up-to-date the classic account by van Bemmelen (1949), written when the mineral deposits in western Indonesia, particularly those in Sumatra, were among the better known and prior to 1942, important contributors to the Indonesian economy.The larger mineral deposits in southern Sumatra have been described briefly by Gafoer & Purbo-Hadiwidjoyo (1986), and are referred to in the regional descriptions of the mineral deposits of SE Asia by Hutchison & Taylor (1978) and Hutchison (1996). In wider-ranging reviews the geological setting of gold and base metal deposits in Indonesia have been discussed by Carlile & Mitchell (1994), while those of tin deposits in SE Asia are catalogued by Schwartz et al. (1995).Sumatra has long been known as a source of gold, the name of the island being derived from the Sanscrit word Svarnadvipa, meaning 'Golden Island', dating from the importance of gold deposits to the rulers of the Hindu kingdoms that flourished in Sumatra from the seventh until the eleventh century. The estimated total production of precious