Suphat Vongvisessomjai


Phuket is a well-known island resort on the west coast of the peninsula of Thailand and it is rich in tin deposits. Tourist and tin mining are conflicting especially in Bang Tao Bay. Before offshore tin mining in the bay, the bathymetry is quite simple/natural and the bay is almost in equilibrium with offshore sand movement by storm waves and onshore sand movement by swell. After tin mining in 1987, people in Villages 4 and 5 sent a petition to district and city officers from May to June 1988 to the effect that offshore tin mining in the bay had caused beach erosion and road damage, and that the dredger owner should be responsible for the cost of repairs. The sounding map makes in this study reveals that deep holes are created by dredgers, those nearshore are found to interrupt the cyclic changes and sand movement on the beach that results in a permanent loss of sand into the dredged holes and causes shoreline erosion; the maximum erosion in the middle of the bay is 40 meters in the 3 years from 1987 to 1990. A field test during May to June 1991 confirms that the high rate of shoreline erosion is consistent with that found in large wave tank experiments. Offshore tin or sand mining should not be made in shallow water where sand is mobile. If offshore mining were allowed nearshore, conditions should be imposed so that the bathymetry in the vicinity of the offshore mining should not change significantly.


mining; tin minig; offshore mining; erosion; shoreling erosion

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