title: Radon emanation from backfilled mill tailings in underground uranium mine.
abstract: Coarser mill tailings used as backfill to stabilize the stoped out areas in underground uranium mines is a potential source of radon contamination. This paper presents the quantitative assessment of radon emanation from the backfilled tailings in Jaduguda mine, India using a cylindrical accumulator. Some of the important parameters such as (226)Ra activity concentration, bulk density, bulk porosity, moisture content and radon emanation factor of the tailings affecting radon emanation were determined in the laboratory. The study revealed that the radon emanation rate of the tailings varied in the range of 0.12-7.03 Bq m(-2) s(-1) with geometric mean of 1.01 Bq m(-2) s(-1) and geometric standard deviation of 3.39. An increase in radon emanation rate was noticed up to a moisture saturation of 0.09 in the tailings, after which the emanation rate gradually started declining with saturation due to low diffusion coefficient of radon in the saturated tailings. Radon emanation factor of the tailings varied in the range of 0.08-0.23 with the mean value of 0.21. The emanation factor of the tailings with moisture saturation level over 0.09 was found to be about three times higher than that of the absolutely dry tailings. The empirical relationship obtained between (222)Rn emanation rate and (226)Ra activity concentration of the tailings indicated a significant positive linear correlation (r = 0.95, p < 0.001). This relationship may be useful for quick prediction of radon emanation rate from the backfill material of similar nature.
authors.affiliation: Department of Mining Engineering, Indian School of Mines, Dhanbad 826 004, Jharkhand, India.
authors.forename: Patitapaban
authors.initials: P
authors.lastname: Sahu
authors.affiliation: Department of Mining Engineering, Indian School of Mines, Dhanbad 826 004, Jharkhand, India. Electronic address: devi_agl@yahoo.com.
authors.forename: Devi Prasad
authors.initials: DP
authors.lastname: Mishra
authors.affiliation: Department of Mining Engineering, Indian School of Mines, Dhanbad 826 004, Jharkhand, India.
authors.forename: Durga Charan
authors.initials: DC
authors.lastname: Panigrahi
authors.affiliation: Environmental Assessment Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
authors.forename: Vivekananda
authors.initials: V
authors.lastname: Jha
authors.affiliation: Environmental Assessment Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
authors.forename: R Lokeswara
authors.initials: RL
authors.lastname: Patnaik
authors.affiliation: Environmental Assessment Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
authors.forename: Narendra Kumar
authors.initials: NK
authors.lastname: Sethy
mesh_terms: D004058:Diffusion; D007194:India; D008906:Mining; D008962:Models, Theoretical; D011834:Radiation Monitoring; D011886:Radon / Q000032:analysis*; D012990:Soil Pollutants, Radioactive / Q000032:analysis*
chemical_list: D012990:Soil Pollutants, Radioactive; D011886:Radon
keywords: (222)Rn emanation rate; (226)Ra activity concentration; Backfilled mill tailings; Emanation factor; Moisture content; Underground uranium mine