INNOVATIVE CAUTIOUS BLASTING TECHNIQUE FOR EXCAVATION CLOSE TO A RUNNING HYDROELECTRIC POWERHOUSE - A CASE-STUDY

The paper reports a case where blasting was conducted to remove 10 000 m(3) of granite very close to a running powerhouse without causing an y visible or invisible damage to the powerhouse complex due to ground vibration or fly rock, A muffle bucket, designed on the basis of dynam ic load concept was used both for the muffling and loading operations, The bucket displacement due to throw of rock fragments and the averag e fragment size were found to be directly dependent on the specific ch arge. Analysing the results of more than 300 blasting events suggests a new approach for very accurate prediction of peak particle velocity.