The mineralogical study of heavy minerals from tin-mines in Kathu valley ,Changwat Phuket

Abstract

Kathu Valley is located in the central part of Phuket Island covering an area of approximately 10 square kilometers. About sixty-five per cent of the total tin-concentrate production of Phuket comes from existing tin-mines in Kathu Valley and neighbouring area. Besides, there are a variety of detrital heavy minerals associated with cassiterite deposit in this area. The purpose of the present investigation is to study the heavy mineral associations of fifteen tin-mines in Kathu Valley and neighbouring area. Particular emphases have been given to the physical properties of each mineral, grain size distribution, degree of abundance, and their interrelationships. In addition, the detailed geological setting of each sampling location has been conducted to facilitate the interpretation of heavy mineral suites particularly regarding to their genesis. The common heavy minerals of eight tin-mines within Kathu Valley are cassiterite with manganese coat, cassiterite interlocking with quartz, garnet, limonite, manganese oxide, monazite, xeno-time, mica, tourmaline and zircon. The most abundant heavy minerals are cassiterite including cassiterite with manganese coat and cassiterite interlocking with quartz. Other accessorial minerals are Feoxide, rutile, spinel, topaz, wolframite, columbite-tantalite, mangan-tantalite, allanite, apatite, leucoxene, limonite, struverite, multiple oxide containing Nb-Ta, and magnetite. The nature and characteristics of heavy mineral assemblages from seven tin-mines outside the Valley are generally fairly similar to those within the Valley. The main differences are some minerals which are found only in some localities outside the Valley, namely, hematite, pyrite, siderite, thorite, fluorite, scheelite, arsenopyrite and altered pyrite. The only variety of cassiterite with manganese coat is present only in Kathu Valley. Additional attempts have been made to determine the relationships between grain size parameters of cassiterite against others heavy minerals in terms of mean, median and sorting. Moreover, the variation of relative degree of abundance of heavy minerals with respect to grain size characteristics has been studied. Special attention has also been paid on the distribution patterns of some economically important heavy minerals: cassiterite, columbite-tantalite, columbium-tantalum (struverite), zircon, monazite, xenotime and ilmenite. Finally, the characteristics of heavy minerals including the interrelationships between their numerous parameters have been explained in the light of their genesis for Kathu Valley and neighbouring area. The findings of the present investigation can be applied to many other important aspects, notably, the determination of potential heavy mineral resource, the design and development of appropriate ore dressing technique, the exploration of heavy minerals, etc.