6. Underground Ring Blasting

Ring blasting method is practised for the final excavation of rock mass in longhole stoping. The method is advantageous in achieving the faster production pace due to the use of large diameter drilling and blasting. However, this method has many associated operational challenges. These challenges have been overcome using the technological innovations. It has been possible to undertake ring blasting up to the depths of 50 m with the help of multi-deck firing. The advent of electronic delay detonators has given additional ease to the blast designers in planning and implementing of multi-ring blasting. The selection of optimal blast geometry, charging pattern and delay sequence is also important to obtain the desired output from a ring blast. Various empirical, numerical and statistical models have been developed by the researchers for the computation of these parameters. In this chapter, the process of ring blasting and designing of blasting parameters for a ring blasting has been discussed in detail. Some of the experimental data from the case studies at Indian underground mines have also been discussed in this chapter.