V-Type Firing Pattern in Blasting: Evidence to Substantiate the Improved Fragmentation

Firing sequence of blastholes in blasting is an inherent part of the blast design for various reasons that range from the spatial requirements to the control of throw during blasting in surface mines. Despite several such patterns in vogue, role of firing sequences in defining the size of fragmented block sizes is not properly understood. The V-type firing pattern is believed to improve blast fragmentation because of the collision of moving fragments during the blasting process, thus resulting in further breakage. There are practically negligible studies that substantiate this assertion. The role of V-type firing pattern has been explored in this paper with simple logic and some field data. It is observed that the V-type firing pattern produces better fragmentation and controls the throw during blasting. A comparison with diagonal firing pattern, in controlled experiments, makes it evident that V-type firing pattern can be used to advantage for fragmentation improvement.