ABSTRACT
Highwall mining is seen as a promising method in India to extend the life of open pit coal mines by extracting locked-up coal from multiple seams exposed at the batters and final highwall slope. In this chapter detailed design methodology adopted for all the initial highwall mining projects viz. (i) Ramagundam Opencast Project-II and (ii) Medapalli Opencast Project of M/s Singareni Collieries Company Ltd. (SCCL), (iii) Quarry SEB and Quarry AB, West Bokaro of M/s Tata Steel Ltd. (TSL) and (iv) Sharda Highwall Mining Project of M/s South-Eastern Coalfields Ltd. (SECL) is elucidated. The design techniques involved coupled empirical and numerical modelling techniques for multiple seam web pillar design so as to maximize the recovery without affecting the surface features in long and short-term. Also narrated is the field experience from these sites including the machine performance analysis for SCCL sites. A trench design methodology developed for multiple seam trench highwall mining and its successful application at Sharda Highwall Mining Project is also explained. All the precautionary measures recommended and implemented at these sites, including the safe blasting techniques in the surroundings, slope stability evaluation, ground monitoring techniques, pre-split blasting techniques for trench excavation, etc. are described.
