Blasthole jet drilling parameters evaluation by test rig

Abstract

The jet drilling method has significant advantages over mechanical ones. The article presents the results of the theoretical and experimental jet drilling apparatus for drilling blast holes in hard rocks granite and gneiss studies using the developed test rig. The main difference between the studied device and traditional thermal spallation drills is the low temperature of the working fluid. The specific energy consumption method was proposed to evaluate parameters of the jet drilling apparatus for various rocks types. It has been shown that minimal specific energy consumption for hard rocks is obtained with minimal chamber pressure sufficient for reaching certain Mach number at the nozzle exit. The developed test rig has experimentally shown a stable drilling process and, at the same time, a long durability of the apparatus.