Generic protocol for loading and firing of explosives (surface mining)

Blasting is a complex activity demanding special skills on the part of the blaster and other crew members. It requires a careful coordination of tasks between the blasting crew and other employees working in the vicinity of the blast site. Before loading explosives in a borehole, the blaster will generally examine the drilling logs to identify potential problem areas such as presence of mud seams, voids, or geological anomalies. This is followed by a visual inspection of the highwall face and bench top. The blaster should look for presence of overhangs, back breaks, softer stratum, and other irregularities. Laser profiling data, if required, is examined at this time. Based on the approved blasting plan and the results of examination, the blaster will calculate the charge weight, geometry, stemming, and other parameters. Safety considerations dictate that employees not associated with loading and blasting operations should leave the blast site. Blast sites should be secured and warning signs posted before loading boreholes. The blasting machine or the firing key should be securely kept by the blaster during the entire process of loading and hook up to prevent any unintentional detonation. The Code of Federal Regulations (CFR), Title 30, Part 56.6306 prohibits driving vehicles and equipment over explosive material or initiating system. The rise of an explosive column in a borehole should be checked during the loading process. The blaster should know and adhere to safe operating procedures. The blaster or a designated employee should connect the individual holes to the firing line. It is a good practice to walk along the firing line to reexamine the connections. If any instrumentation for recording ground vibration and air blast has been deployed, it should be checked and set at this time. Next, the blaster should clear all employees from the blast area, post guards at all entrances to the blast area, and communicate to the mine foreman about the impending blast. The blaster (and helpers, if any) should go outside the blast area or stay inside a blasting shelter. Upon receiving clear and unambiguous feedback from the guards and mine foreman, blast signals are sounded and the shot is fired. Rock blasting releases a tremendous amount of energy in a very short time span. It is imperative to establish an effective protocol to maintain blast area security. Before sounding an all-clear signal, the blaster should conduct a visual inspection of the blast site and check for undetonated explosives, misfires, and other problems. The blasting log should be finalized at this time. Finally, all unused explosives should be returned to the magazine.

by T. S. Bajpayee, T. R. Rehak, G. L. Mowrey, and D. K. Ingram