Patents
The invention provides a method for solid blasting in underground coal mines using spacer-aided-initiation technique relates to solid blasting in development faces of underground coal mines for improving pull, blast economics, fragmentation and reducing ground vibration, noise and generation of fines or boulders. In contrast to the existing method of solid blasting wherein continuous column of P5 type of explosive cartridges are loaded to the bottom of the hole, in the present invention Spacer-Aided-Initiation (SAI) technique is used for providing air decking between the explosive cartridges with the help of spacers in solid blasting in underground coal mines. Length of spacers (i.e. air decking length) are decided based on the results of laboratory and field studies for air gap sensitivity of different P5 permitted explosives so that air decked cartridges get initiated by sympathetic detonation using single detonator in a hole. Trial blasts in different SCCL underground coalmines have shown promising results with increase in pull, yield and fragmentation and reduction in socket formation, ground vibration and noise.