Identifying phlogopite mica mineralization in the area around Rathnapura and suggesting suitable mining methods for sustainable exploitation

Abstract

Investigation carried out in the area around Rathnapura shows occurrence of economically valuable phlogopite mica mineralization in the area. Such deposits are concentrated in Hindurangala, Palkumbura, Pathagammana, Yakodiyadeniya, Thambandeniya and Kosgala. Although historical data show systematic underground mining has been carried out in some places, present mining activities are restricted to very small scale pits dug haphazardly. Vein thickness of the phlogopite mica varies from 2 cm - 1 m and extends in N 35°- 50° W direction. They generally follow the foliation pattern of the metamorphic country rocks and three major mineralization zones extending over 10 km have been found in the area. In some locations veins follow joint directions of the area. Variation in physical properties such as colour, expansion and permanent colour changes due to heat are found in the same mineralized zone in different locations.