Evaluation of Exposure to Radon Progeny During Closure of Inactive Uranium Mines – Colorado

Details

• Personal Author:
  Daniels, Robert D. ; Sylvain, David C.
• Corporate Authors:
  National Institute for Occupational Safety and Health
• Description:
  In June 2011, NIOSH received an HHE request from managers of a federal agency in Colorado. NIOSH was asked to evaluate employees' exposure to ionizing radiation hazards during construction of various types of closures at abandoned uranium mines. The primary health concern at these sites involved inhalation of naturally occurring short-lived radon progeny (i.e., polonium-218, lead-214, bismuth-214, and polonium-214) at mine entrances (adits). Also of concern, but to a lesser extent, was exposure to gamma radiation emitted from mine waste and nearby geological formations. On September 12-15, 2011, we visited several abandoned mines on Wedding Bell Mountain in southwest Colorado and the Vanadium Queen mine in Utah. We observed the construction of a native stone and mortar closure on Wedding Bell Mountain. We also conducted continuous monitoring of radon progeny at several mine openings at Wedding Bell Mountain and at the Vanadium Queen mine. We reviewed the state inactive mine reclamation program's pre-bid radon monitoring protocol. Monitoring results and onsite observations suggest that employee exposures to radon during mine closure activities are generally low. However, radon concentrations at mine openings are greatly affected by changing environmental conditions such as wind velocity, moisture, and barometric pressure. Results of NIOSH exposure monitoring did not exceed the average pre-bid PAEC values obtained during previous monitoring by state inactive mine reclamation program staff. Nevertheless, PAEC results from the CWLMs varied widely over the sampling period because of constant fluctuations in ventilation patterns. Given this variability, it is unlikely that shortterm sampling, as conducted by state inactive mine reclamation program staff, is sufficient to derive long-term average concentrations that form the basis of protective actions. Control measures are needed in some instances to keep exposures as low as reasonably achievable (ALARA). Gamma radiation is likely to be measureable at the surface of waste rock piles near mine adits. Occupancy to these areas should be limited to minimize exposures to radon. The use of simple engineering controls (e.g., barriers, ventilation), along with the use of respiratory protection when needed, are recommended to keep radon exposures ALARA.
• Subjects:
  Mining Occupational Health Radiation Radon Safety Uranium
• Keywords:
  Administration Of Conservation Programs Gamma-radiation Gamma Radiation Inactive Mine Reclamation Ionizing-radiation OSHA Region 8 Radon Radon-daughters Radon Progeny Underground-mining Uranium-mining Uranium Mines

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• Source:
  Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, HETA 2011-0090-3161, 2012 Jul ; :1-35
• Series:
  Health Hazard Evaluation Reports (HHE)
• Subseries:
  Health Evaluation and Technical Assistance (HETA)
• DOI:
  https://doi.org/10.26616/NIOSHHETA201100903161
• Publisher:
  National Institute for Occupational Safety and Health
• Document Type:
  Text
• Genre:
  Field Study
• Place as Subject:
  Colorado ; OSHA Region 8
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  DSHEFS - Division of Surveillance, Hazard Evaluations, and Field Studies
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  44 pdf pages
• Contributor:
  Booher, Donald E. ; Evans, Stefanie M. ; Feldmann, Karl D. ; Galloway, Ellen ; Hartle, Greg ; Winfree, Mary
• NIOSHTIC Number:
  nn:20041128
• NTIS Accession Number:
  PB2012-112932
• Citation:
  NIOSH [2012]. Health hazard evaluation report: evaluation of exposure to radon ; progeny during closure of inactive uranium mines – Colorado. By Daniels R, ; Sylvain D. Cincinnati, OH: U.S. Department of Health and Human Services, ; Centers for Disease Control and Prevention, National Institute for Occupational ; Safety and Health, NIOSH HETA No. 2011-0090-3161,
• CAS Registry Number:
  Uranium (CAS RN 7440-61-1) ; Radon (CAS RN 10043-92-2) ; Polonium (CAS RN 7440-08-6) ; Lead (CAS RN 7439-92-1) ; Bismuth (CAS RN 7440-69-9)
• Federal Fiscal Year:
  2012
• Peer Reviewed:
  False
• NAICS and SIC Codes:
  924120 - Administration of Conservation Programs - (NAICS)
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:6a97b313b89e3712c3be31c5b344f6132e869cd7b39ffa4c75d1d3bb69f5babebcbe0b74e0ea30099e154dbb89b8c13cbcd6556798e1182e2a13ecedfcdedf16
• Download URL:
  https://stacks.cdc.gov/view/cdc/172483/cdc_172483_DS1.pdf
• File Type:
  [PDF - 4.46 MB ]