Application of the RACAL Airstream Helmet in Four Underground Coal Mines

Abstract

Abstract The Mine Safety and Health Administration (MSHA) conducted field studies on the RACAL Airstream Helmet to determine its suitability as an interim personal protective device in underground coal mines where technology is inadequate to control dust. The studies of the RACAL Airstream Helmet were conducted in four underground longwall mining sections to evaluate user acceptance and the helmet's applicability to the coal mine environment and to determine the life expectancy of its final filter. User acceptance and applicability to the coal mine environment were assessed using responses to a questionnaire by miners participating in the studies who wore the helmet in the mines and by actual use of the helmet by personnel conducting the survey. In general, the miners who participated in the study felt that the helmet afforded them personal protection against dust. However, use of the helmet on a continuing basis did present specific problems that would make its universal acceptance questionable. The life of the final filters was determined by monitoring daily the decrease in air quantity through the helmet. The data obtained showed a correlation to previous work conducted in the laboratory in which there was determined to be a relationship between life of the final filter and total airborne dust exposure. This article summarizes the survey procedure used, outlines specific problems associated with the helmet, and consolidates the results obtained from the four underground evaluations conducted.