In-depth survey report: control technology comparative evaluation of rock-drilling rigs at Trumont Quarry, Hopkinton, Massachusetts, report no. ECTB-210-11a.
A field study was conducted to comparatively evaluate the dust control technologies on three, track-mounted, rock-drilling rigs, This equipment is used in a wide variety of industrial applications including mining, transportation, and construction activities. These rigs operate on the principle of percussion drilling, using either compressed air or fluid to power the rig. Uncontrolled rock drilling is notorious for generating high concentrations of respirable dusts, including crystalline silica. Silicosis, a progressive, disabling, and sometimes fatal lung disease, has been recognized in the rock-drilling workforce (NIOSH Alert, DHHS Publication No. 92-107). The respirable dusts are generated because compressed air is used to flush the rock cuttings up from the drill hole. Three rigs were evaluated. The first rig used water to suppress dust emissions. The second rig used water and a dust collection system to suppress emissions. The third rig was equipped with the preceding controls and an enclosed, ventilated operator cab. Video-exposure monitoring, using handheld aerosol monitors, was the primary technique used to identify and evaluate exposure variations from rig to rig. The monitoring results demonstrated that as the level of engineering control increased, the exposures decreased. The exposure reduction of the second rig was 61 to 70 percent when compared to the first rig, and the exposure reduction of the third rig was 61 to 87 percent when compared to the first rig. Several work activities notably increased exposures such as "collaring the hole" at the beginning of the operation and "blowing out the hole" at the end of the operation. The driller reduced his exposures by staying upwind of the dust plume when not making adjustments at the drill controls.
Region-1; Control-technology; Control-equipment; Control-methods; Engineering-controls; Dust-control; Dust-control-equipment; Dust-exposure; Dust-particles; Dust-suppression; Dusts; Silica-dusts; Quartz-dust; Quarry-workers; Quarries; Surface-mining; Road-construction; Construction-industry; Construction-equipment; Pneumatic-tools; Pneumatic-equipment