Statistical interpretation of a frequency-of-monitoring program designed for the protection of underground uranium miners from overexposure to radon daughters

CIM Bulletin, Vol. 73, No. 824, 1980

C.E. MAKEPEACE and H. STOCKER, Atomic Energy Control Board, Ottawa, Canada

This paper presents the statistical analyses of several sets of data acquired in several programs of sampling of radon daughters in uranium mines. The measurements were taken over periods of days or weeks for given locations or location-occupations within these mines. Because the sampling applies to specific intervals of time and specific locations, a method is suggested for the eventual application of a monitoring program which would be suitable on an annual basis for these locations. The present data and analyses thereof are not justifiably applicable to a monitoring regimen on an annual basis, without a number of additional assumptions.The aim of the present analyses of concentration measurements is the determination of the minimum number of measurements required to achieve an annual radon daughter exposure estimate, for individual workers, having an error no greater than 50% at the 95% confidence level. The criterion of accuracy is taken from a statement in the American National Standard, Radiation Protection in Uranium Mines (ANSI Nl3.8-1973), and is currently used, in somewhat modified form, as a guide to uranium mining licensees in Canada. Uncertainties associated with occupancy time are ignored in the present analysis.
Keywords: Mine safety, Monitoring, Underground mining, Uranium mining, Radiation, Radon daughters, Sampling.