R11-1-470. Sampling for radon daughters

In all underground mines at least one sample shall be taken each year in exhaust mine air by a competent person to determine if concentrations of radon daughters are present. If concentrations of less than 0.1 WL are found: 1. Where uranium is not mined, no further exhaust mine air sampling is required during that year. 2. Where uranium is mined, at least one sample shall be taken in the exhaust air each month. 3. Results of these tests shall be recorded and retained at the operation and be made available for inspection.