Investigation of Quartz Dust Sources and Control Mechanisms on Surface Coal Mine Operations. Volume 1. Results, Analysis, and Conclusions

摘要

The basic objective of the study was to evaluate the sources of airborne quartz dust during removal of overburden at surface coal mines to which the highwall driller, drill helper, truck driver, and bulldozer operator are exposed. Testing was conducted at 11 mine locations. Both dry and wet control systems for overburden drills were evaluated at the various mines. The test results showed that both control systems are capable of achieving greater than 95% control under certain conditions. On dry systems, a nearly linear inverse relationship was found between shroud height and control efficiency. Control efficiencies ranged from 41% to 99% over the 0- to 27-in. height range evaluated. Dry systems performed most efficiently when the shroud was positioned as close to the ground as possible. For wet systems, measured control efficiencies ranged from 9% at a water flow rate of 0.2 gal/min to 96% at 1.2 gal/min. Water flow rates greater than 1.0 gal/min were found to cause operational problems. Quartz concentrations of the respirable particulate ranged from below detectable limits to 13.6%.