Abstract
In May, 1991, the U.S. Secretary of Labor directed the Assistant Secretary for Mine Safety and Health to conduct a thorough review of the program to control respirable coal mine dust in the nation's mining operations. In response to that directive, the Assistant Secretary established the Coal Mine Respirable Dust Task Group, whose purpose was to study and recommend improvements to the program to control respirable coal mine dust. The Task Group concluded that new technology for continuous monitoring of the mine environment, and of the parameters used to control dust, offer the potential to improve the Mine Safety and Health Administration's dust enforcement program. The primary long-term recommendation made by the Task Group was that an accelerated research program be initiated to evaluate existing state-of-the-art technologies with the potential to be used in a fixed-site underground coal mine dust monitor. The instrument would provide continuous information to the miner and mine operator on the status of dust resulting from the mining process. To accommodate the recommendation, the Mine Safety and Health Administration and the Bureau of Mines instituted a joint-venture program for the development of such a monitor. In the meantime, the Mine Safety and Health Administration has undertaken a program to assemble and evaluate the application of a fixed-site monitor capable of continuous sampling, using current sampling technology, on a continuous-mining operation. The Mine Safety and Health Administration's program consists of assembling three coal mine personal sampler units into a package and programming them to sample the mine environment sequentially during each working shift (first, second, and third). The sample collected for each respective shift is cumulative for up to 7 days. The samples are analyzed to determine the average multiday respirable dust concentration. The data were analyzed to determine long-term sample variability, as well as intershift variability. This article presents the details of the design of the continuous monitor, its application, and a discussion of the data collected.