ABSTRACT
Explosive is the most commonly used energy to fragment the rock mass in mining and civil engineering projects. Main objective of blasting in mining projects is to obtain the maximum yield with desired fragmentation in a safer manner with minimum side effects like ground vibrations, noise and fly rock, while in civil engineering projects it is to create space. Assessment of each blast is necessary keeping the objective of the blast in view. Blast results can be categorized into two groups of desirable fragmentation and unwanted results like ground vibrations, noise and fly rock. In addition, there are some more minor undesirable results like back break, toe formation etc. A number of factors influence the blast results, which can be grouped into controllable and uncontrollable factors. Parameters like explosive type, burden, spacing, sub drilling, stemming, delay timing, charge weight per delay, initiation system, initiation pattern etc., may be grouped under controllable parameters. Geological parameters like mineralogy, lithology, structural discontinuities and physico-mechanical properties of rock mass come under uncontrollable factors, as they are given by nature. Initiation system is one of the major parameters that influence the blast results considerably. Assessment of blast results in terms of fragmentation forms a major basis while evaluating the influence of various parameters.
