Development of site specific blasting index parameters based on single hole blast test cratering

ABSTRACT An experimental method is proposed to assess blasting requirements based on in-situ cratering behavior. The method relies on single hole blast (SHB) tests to derive burden-dependent relationships. A non-linear crater model of the form is calibrated from SHB test results to describe the cratering behavior. Parameters and represent characteristic blastability index parameters that depend on geomechanical and operational conditions. A series of experimental SHB tests were conducted at three hard rock mines. The craters were mapped to capture the breakout profile and calibrate the model. Results showed that coefficient presents an inverse linear correlation with burden , while exponent s is approximately constant for a considerable range of burden values. Experimental results are used to define burden dependent relationship for bench blast designs and blasthole placement in underground development rounds. A complementary analysis addresses the prevalence of multiple cratering mechanisms according to geology and burden dimension.