A study of placer tin materials from southern Thailand

This thesis deals with a series of investigations of placer tin samples from a Chinteik\u27s Tin-dredge, Gnaw District, Ranong Province, and the Tin-Pet mine, Phang-gna Province, in southern Thailand. A brief summary of the geography and geology of Thailand as a whole has been given as a general introduction to the source of the materials studied in this thesis. The results of sieve analyses have shown that the sluice boxes do not effectively concentrate the cassiterite grain below 0.147 mm. from the rough concentrate treated in the tin-dressing shed. It has been found that roundness and shape determinations of quartz grains from relatively short transportation placer deposits do not give sufficient data as environmental guides. The quartz grains investigated give good, comparisons with the reworked quartz grains of St. Peter sandstone on one hand and with artificially crushed quartz fragments on the other hand. Mass magnetic susceptibilities of some magnetic minerals from Tin-Pet mine have been established with a Frantz Isodynamic Separator. Tantalite-columbite (mass magnetic susceptibility = 23.48 x 10-6 C. G. S. max.) can be separated from Ilmenite (mass magnetic susceptibility = 52 x 10-6 C. G. S. max.). Magnetic separation and microscopic examination of ilmenite grains from Tin-Pet and Tin-dredge mines confirm the works of other workers, i.e. , that this mineral has altered to many phases due to weathering processes. Advanced alteration of phase two and three were found to occur in a majority of ilmenite grains from Tin-dredge than those from Tin-Pet mine. These highly altered ilmenite grains have lower mass magnetic susceptibility than the less altered ilmenite grains. Major metallic minerals from the two tin placer deposits were described and the properties of each mineral under the reflected light microscope have been given. Percentage and interlocking determinations of each sample have been recorded each on separate tables --Abstract, pages xii-xiii