What precautions will be taken:Making an overburden dump in big opencast mine using draglines

Precautions in making OB dump in a dragline mine:                                                                            Height and slope of dump face should be designed by a research institute based on type of OB,seam dip,nature of floor, drainage,reach and dumping height of dragline production etc.Interface layer I.e.debris or coal dust,fragmented rock soil mixed with water should be cleared as far as possible from the de-coaled floor  before dumping by dragline starts.If it cannot be avoided,the floor should be ripped or blasted to a depth of 1-1.5m before start of dumping by dragline to improve frictional resistance at base of the dump.Top soil should be dumped separately.Under no circumstances should such material be placed at base of the dump.OB excavated from shovel dumper benches should not be dumped on or near the fresly created dragline dump to avoid further loading of partially consolidated dragline dump Ideally,it should be dumped atleast two cuts away.Valleys in dragline dump should be levelled to avoid rain water ponding between heaps of dragline dump.If coal rib is left at floor level the rib should be punctured at every 100-150m to prevent accumulation of water behind it. Annual Production target should be so fixed as to provide adequate dumping space with safe dump height and slopes.Dump height and slope should be monitored regularly by trained personal using sophisticated survey instrument. Trained competent person should be deployed for frequent inspection of the sump.If there are any cracks or other signs of deterioration of stability,he should inform the manager forthwith.Manager should frame and implement dumping rules incorporating all the above points.