On March 22, a 42-year-old lead man with six years of mining experience was fatally injured at a Martin Marietta Materials plant when he was struck by fly rock from blasting operations. The lead man was parked in his pickup truck at a location to prevent others from accessing the blasting site. He was approximately 1,200 ft. from the blast area.
This is the third fatality reported in calendar year 2016 in metal/nonmetal mining. As of this date in 2015, there were six fatalities reported in metal/nonmetal mining. This is the first Blasting and Breaking Agents fatality in 2016. There were no Blasting and Breaking Agents fatalities in the same period in 2015.
MSHA suggest the following best practices to avoid this type of fatality.
- Review and follow site specific blast plan prior to loading any explosives.
- Utilize technology, such as face profilers and borehole probes, to obtain specific geometric details of the material to be blasted.
- Adjust stemming depth and/or decking to maintain adequate burden on all sections of the blast hole.
- Develop a drill pattern by considering geology, face geometry, and surface topography.
- Clear and remove all persons from the blast area unless suitable blasting shelters are provided to protect persons from flyrock. Allow at least 15 seconds after a blast for any flyrock to drop.
- Examine blast site geology, communicate with the driller and review the drill log for angles, voids, competency of rock, loss of air, etc., prior to the loading any explosives. Make appropriate adjustments to ensure that the holes are not overloaded.
- Ensure blasting and fly rock areas are properly calculated to ensure the blast site is clear of all persons.
- Determine the actual burden for all face holes along their length and adjust the explosive power factor along the borehole accordingly.