Stope Stability in Underground Manganese Mine - A Case Study of Munsar Mine of MOIL Limited

摘要

MOIL Limited is operating 7 underground and 3 opencast mines in central India and producing annually more than 1.2 million tonnes of various grades of manganese ore. The Munsar mine is being worked since 1903. The opencast mining is presently stopped. The ore body below the opencast quarry is geological continuity of the area excavated in past by underground mining through the adit in three levels i.e. 270'L, 220'L, 170'L and by incline in western part of the property at 70'L. The horizontal drift development has been developed in the manganese ore body with sill drive 5 m above the sill pillar in lower level at 70'L and barrier pillar of 5 m thickness is left for protection of upper level at 170'L. Valuable mineral has been locked in sill pillar and therefore stope stability design, investigations and analysis have been carried out for excavation of manganese ore. On the basis of study now the drift development has been carried out in footwall rock at 70'L, (-) 30'L and below levels and it has improved the mineable manganese ore by about 20%. The paper presents stope stability design, modeling and changes in stoping method for better safety and productivity at Munsar Mine