Control of Workplace Environment During Rock Excavation Near Super Sensitive Structures

Extensive rock excavations by conventional commercial explosives have been the basic need during Stage-Il (4x500 MW) commissioning work at Kaniha Thermal Power-plant of the National Thermal Power Corporation Ltd. (NTPC) in Orissa. There are very sensitive structures and installations like various water feeding pipelines either buried or exposed, CWC pump-house, control panel, high tension cables, water purification plant, water reservoir, underground concrete casing, chimney and centralised plant installations; which are all within 2 to 30 m distances from different excavation sites. Workplace environment which includes noise, air-overpressure, vibration and fly-rock are required to be strictly controlled through safe blast designs during various stages of rock excavation. CMRI adopted such design patterns and conducted more than 250 blasts using such patterns in order to implement them for faster progress of the work. This paper focuses some of the salient features on design aspects and a few interesting results obtained thus far.