Handling the blockades while excavating the surge shaft at Tala Hydroelectric Project

Every component in a hydel project is an important element. Delay in any one component will affect the project time and cost equally. Excavation of surge shaft is one such component which happens to be the most critical as it involves multiple stages for its completion. This operation as such is slow, difficult and if it encounters adverse geology the operation puts the entire project on the critical path. This paper discusses in detail the problems encountered during the entire excavation of a surge shaft for a 1020 MW hydel project in Himalayan geology with special reference to the blockades. It deals with the methods adopted to clear the chokes at various stages of excavation and to achieve the accelerated progress by full face blasting.