Underground Uranium Miners Research Articles

Evaluation of radiation dose associated with underground uranium mining activities in east Singhbhum, Jharkhand, India

This paper presents the effect of ventilation parameters on the 222Rn inhalation dose in an underground uranium mine located in east Singhbhum of Jharkhand, India. This study reveals that the airflow rate variable statistically significantly predicts the 222Rn dose variable in the mine. On the other hand, no significant effect of other ventilation parameters such as barometric pressure, dry-bulb, and wet-bulb temperatures on 222Rn inhalation dose in the stopes was observed due to negligible variations in their values. Therefore, the airflow rate plays a significant role in reducing the effective radiation dose level in mines. In this study, the Equivalent Equilibrium Radon concentration (EER) and total effective radiation dose received by the miners involved in different mining activities in the various locations of the mine were found to be in ranges of 130–420 Bq m−3 and 0–3.17 mSv y−1, respectively. It also reveals that the miners involved in the stope preparation and timbering were exposed to more radiation than other mining activities. Under the existing ventilation conditions, the total effective radiation dose was far below the safe limit of 20 mSv y−1 recommended by the International Commission of Radiological Protection.

Ambient Radiological Condition around an Operating Uranium Mill Tailings Disposal Facility at Turamdih, India

AbstractLarge quantity of the feed forms part of the solid waste (tailings) slurry in the low grade uranium ore processing plant at Turamdih in Singhbhum region of Jharkhand, India. Coarser size fraction of this waste is used for backfilling of the underground uranium mines and fine fraction is discharged into an engineered impoundment system or tailings pond. Since inception of the discharges, field expeditions have been performed as part of the comprehensive radiological monitoring program for the facility. The monitoring program broadly consists of ambient gamma dose rate, atmospheric 222Rn and long lived alpha activity measurement around the facility and the estimation of radionuclide in diverse environmental matrices collected from the adjoining sites. Findings reflect that the radiological conditions are comparable to the pre-existing background level adjoining the tailings pond impoundment. Further, measurements for more than a decade confirm that the atmospheric radon concentration profile just a few meters beyond the embankment is indistinguishable from the background.

Theoretical model for calculating and adjusting radon activity concentration in ventilation networks of uranium mines considering pressure drop effect

The radiation dose of workers in underground uranium mines mainly comes from radon and radon progeny. To ensure a healthy and safe work environment, it is necessary and urgent to optimize the design of ventilation systems. As such, based on the simplified radon diffusion-advection migration model of the rocks, this paper proposes 1) two methods for determining the radon exhalation rate modified by pressure drop, 2) three methods for calculating radon activity concentration of single-branch, and 3) the novel adjustment algorithm and solving procedures for calculating and adjusting the radon activity concentration in ventilation networks by modifying the radon exhalation rate, demonstrated on a specific ventilation network in a simulated underground uranium mine with calculation and analysis via MATLAB. The results show that 1) the radon exhalation rate of different branches can be modified by their pressure drop, and 2) the proposed method can be used to reveal the influences of different ventilation methods and fan pressures on the radon activity concentration in the ventilation network and the radon release rate to the atmosphere.

Contribution of mine water and uranium ore rocks to the 222Rn-induced radiation dose received by the mine workers in a low-ore grade underground uranium mine, India

Contribution of mine water and uranium ore rocks to the 222Rn-induced radiation dose received by the mine workers in a low-ore grade underground uranium mine, India

Assessment of Discharged 222Rn at Surface from Ventilation Shafts of Underground Uranium Mine at Narwapahar in India

Assessment of Discharged 222Rn at Surface from Ventilation Shafts of Underground Uranium Mine at Narwapahar in India

Radiation protection strategies in high-grade underground uranium mines

Radiation protection strategies in high-grade underground uranium mines

An Epidemiological Study of Lung Cancer and Selected Other Cancers among Namibian Uranium Workers.

The Rössing Uranium Limited (RUL) open-cast uranium mine in Namibia has operated since 1976. Studies of underground uranium miners from Europe and North America have shown increased cancer risks (principally lung cancer). We explored the association between radiation doses and selected cancers in RUL mineworkers. Employees with at least one-year of continuous employment between 1976 and 2010 were included. Incident cancer cases [lung, extra-thoracic airways (ETA), leukemia, brain and kidney] occurring before the end of 2015 were identified from the Namibian and South African National Cancer Registries, and RUL's occupational health provider. Using a case-cohort design, data on exposure and confounding factors were collected for all cancer cases among the study cohort and a stratified random sample (sub-cohort) of the cohort, including cases. Radiation doses were estimated based on annual dose records held by RUL. In total, 76 cancer cases (32 lung, 18 ETA, 8 leukemia, 9 brain, 9 kidney) and a sub-cohort of 1,121 sampled from 7,901 RUL employees were included. A weighted Cox model, adjusted for available known confounders, produced a rate ratio (95% CI) for lung cancer of 1.42 (0.42, 4.77) and 1.22 (0.26, 5.68), respectively, for medium and higher cumulative lung dose categories compared to the lower category, and 1.04 (0.95, 1.13) for a dose increase of 10 mSv. This study faced considerable challenges with respect to case ascertainment, exposure estimates, and ensuring accuracy of key variables. Persuasive consistent evidence for elevated cancer risk was not found for radiation or other exposures studied at the Rössing uranium mine.

Comparative study of radon sources and associated health risk in four underground uranium mines.

This paper presents a comparative study of the quantitative estimation of 222Rn and its health risk from various sources in four underground uranium mines. 222Rn exhalation rates from uranium-bearing rocks and backfill materials were estimated by calculating the 222Rn concentration accumulated in an enclosed chamber into which radon was exhaled. This comparative study indicates a more significant effect of porosity on the exhalation rates. Dissolved 222Rn in mine water was estimated using scintillation cell and bubbler kit. The discrepancy in 222Rn concentration in the mines might be attributed to the variation in geological features, ore grade, and porosity. This study revealed that the maximum radon exposure was produced from the backfill mill tailings, followed by uranium ore and mine water in the mines. The radon dose values in the individual mines remained under the safe dose limit of 20mSvyear-1. The excess lifetime cancer risk (ELCR) and 222Rn-induced lung cancer cases (RnLCC) per million persons per year were also estimated.

Delimiting radiation protection distance of underground uranium mining and metallurgy facilities: A case study in China

Delimiting radiation protection distance of uranium mining and metallurgy facilities is an important radiation protection approach to control the effective public dose caused by radon and radon progeny. Ventilation shafts are the main radon release paths of underground uranium mines. It is of great importance to research the diffusion regularities and influence range of the radon around the ventilation shaft. In this study, long-term and short-term radon accumulation monitoring approaches were adapted for onsite investigation. More than 520 sets of radon concentration were acquired. The survey results effectively revealed the distribution regularities of the radon concentration around the ventilation shaft with time, space, and working conditions. These results provide data for radiation protection in uranium mines. In addition, a radiation protection distance delimiting way was proposed for the investigated facility through effective public dose assessment.

An investigation of 222Rn exhalation rates from backfill mill tailings influenced by the different parameters in underground uranium mines

222Rn surface exhalation and mass exhalation rates measured from the backfill mill tailings using a new method comprising the smart-radon-monitor system and accumulation chamber in underground uranium mines are presented in this paper. The range values of 222Rn surface and mass exhalation rates were 0.6–4 Bq m−2 s−1 and 28–71 Bq kg−1 h−1, respectively. Further, Multivariate regression models involving radium content, porosity, moisture saturation and surface area to fit the 222Rn surface and mass exhalation of the backfill materials were developed in this paper. The curve fitting results showed that multivariate models could explain 86% of the variation of surface exhalation rate and 69% of the variation of mass exhalation rate from the backfill materials. This study also revealed that the 222Rn surface exhalation rate calculated based on the method of concentration gradient of 222Rn in soil, found to be about two times more than that of the measured surface exhalation rate. However, the theoretical 222Rn exhalation rate was prone to various uncertainties including a variation of moisture saturation, the occurrence of adsorption and advection in the backfill mill tailings. Therefore, the values of the 222Rn exhalation rate measured inside underground uranium mines are more realistic.

Nonmalignant respiratory disease mortality in male Colorado Plateau uranium miners, 1960-2016.

To evaluate trends of nonmalignant respiratory disease (NMRD) mortality among US underground uranium miners on the Colorado Plateau, and to estimate the exposure-response association between cumulative radon progeny exposure and NMRD subtype mortality. Standardized mortality ratios (SMRs) and excess relative rates per 100 working level months (excess relative rate[ERR]/100 WLM) were estimated in a cohort of 4021 male underground uranium miners who were followed from 1960 through 2016. We observed elevated SMRs for all NMRD subtypes. Silicosis had the largest SMR (n = 52, SMR = 41.4; 95% confidence interval [CI]: 30.9, 54.3), followed by other pneumoconiosis (n = 49, SMR = 39.6; 95%CI: 29.6, 52.3) and idiopathic pulmonary fibrosis (IPF) (n = 64, SMR = 4.77; 95%CI 3.67, 6.09). SMRs for silicosis increased with duration of employment; SMRs for IPF increased with duration of employment and calendar period. There was a positive association between cumulative radon exposure and silicosis with evidence of modification by smoking (ERR/100 WLM≥10 pack-years = 0.78; 95%CI: 0.05, 24.6 and ERR/100 WLM<10 pack-years = 0.01; 95%CI: -0.03, 0.52), as well as a small positive association between radon and IPF (ERR/100 WLM = 0.06, 95%CI: 0.00, 0.24); these associations were driven by workers with prior employment in hard rock mining. Uranium mining workers had excess NMRD mortality compared with the general population; this excess persisted throughout follow-up. Exposure-response analyses indicated a positive association between radon exposure and IPF and silicosis, but these analyses have limitations due to outcome misclassification and missing information on occupational co-exposures such as silica dust.

222Rn Activity Concentration Measurement and its Radiological Risks in the Environment of Barserin Village, Erbil-Iraq

222Rn Activity Concentration Measurement and its Radiological Risks in the Environment of Barserin Village, Erbil-Iraq

Delimiting Radiation Protection Distance of Underground Uranium Mining and Metallurgy Facilities: a Case Study in China

Delimiting Radiation Protection Distance of Underground Uranium Mining and Metallurgy Facilities: a Case Study in China

Hygienic assessment of personnel working conditions in underground uranium mining

The aim of the study is to assess the main radiation-hazardous factors that determine the effective dose of personnel during underground uranium mining at the Priargunsky Industrial Mining and Chemical Association, and to summarize the data of the radiation control of the enterprise for 2016-2020. The main factors that create personnel dose loads are: the volume activity of short-lived daughter products of radon decay in the air, the dose rate of external gamma radiation, and the volume activity of long-lived alpha-emitting radionuclides of the uranium-radium series in industrial dust. Information on the structure and values of individual effective doses of workers is presented. Recommendations for improving the radiation monitoring system are given.

Quantitative Proteomics Analysis of Differentially Expressed Proteins in Serum of Former Uranium Miners by Isobaric Tags for the Relative and Absolute Quantitation.

The carcinogenicity of radon has been convincingly documented through epidemiological studies of underground miners. However, there is a lack of early warning indicators for radon radiation damage. In this study, mixed serum samples of 3 groups were collected from 27 underground uranium miners and seven aboveground miners according to the radiation exposure dose. The differentially expressed proteins in the serum were identified using the isobaric tags for the relative and absolute quantitation (iTRAQ)-based method. Some differentially expressed proteins were validated by enzyme-linked immunosorbent assay (ELISA) in 84 underground and 32 aboveground miners. A total of 25 co-differentially expressed proteins in 2 underground miner groups were screened, of which 9 were downregulated and 13 were upregulated. Biological process analysis of these proteins using Metascape showed that 5 GO terms were enriched, such as negative regulation of very-low-density lipoprotein particle clearance, endocytosis, and regulated exocytosis. The results of the ELISA for the expression levels of GCN1, CIP2A, and IGHV1-24 in the serum of 116 miners’ serum showed that the levels of GCN1 and CIP2A were consistent with the iTRAQ results. In conclusion, APOC1, APOC2, APOC3, ORM1, ORM2, ANTXR1, GCN1, and CIP2A may be potential early markers of radon radiation damage.

Lung and extrathoracic cancer incidence among underground uranium miners exposed to radon progeny in the Příbram region of the Czech Republic: a case–cohort study

ObjectivesRadon is carcinogenic, but more studies are needed to understand relationships with lung cancer and extrathoracic cancers at low exposures. There are few studies evaluating associations with cancer incidence or...

Sources of Radon and its Measurement Techniques in Underground Uranium Mines – An Overview

Purpose This study aims to identify the potential sources of radon exhalation and its measurement in underground uranium mines to control the radiation levels within safe limits and protect miners from radiation hazards. Methods An extensive literature review on radon exhalation in underground uranium mines from various sources such as uranium ore, backfill tailings and mine water has been carried out. The influence of different important factors, viz. ore grade, porosity, grain size and moisture content on radon exhalation has been discussed in depth. Different methods for the measurement of radon exhalation from various sources in mines have also been presented in this paper. Results The review of literature revealed that the radon exhalation rate in porous uranium bearing rocks is less affected by the ore grade than in non-porous rocks. The exhalation of radon from backfill tailings is quantitatively more significant than from the uranium ore itself due to higher bulk porosity and enhanced surface area. Thus, porosity is the dominant factor that affects the rate of radon exhalation from rock surfaces into mine openings. Practical implications The knowledge of the sources of radon and quantitative estimation of radon from various sources will be very much useful in the planning and designing of ventilation systems in underground uranium mines. The accurate measurement of radon exhalation in underground uranium mines can be made by choosing the optimum size of accumulation chamber and a suitable radon build-up period in the chamber. Originality/value The study portrays the important sources of radon and its measurement techniques in underground uranium mines based on an extensive literature review. The methods of measurement of radon exhalation from the ore body and backfill tailings in underground uranium mines, used by the authors of this paper, comparatively give more accurate results than previously used methods. Furthermore, the methods are more effective in terms of portability, cost and time for measuring the average radon exhalation across a large.

Sources of Radon and its Measurement Techniques in Underground Uranium Mines – An Overview

Purpose This study aims to identify the potential sources of radon exhalation and its measurement in underground uranium mines to control the radiation levels within safe limits and protect miners from radiation hazards. Methods An extensive literature review on radon exhalation in underground uranium mines from various sources such as uranium ore, backfill tailings and mine water has been carried out. The influence of different important factors, viz. ore grade, porosity, grain size and moisture content on radon exhalation has been discussed in depth. Different methods for the measurement of radon exhalation from various sources in mines have also been presented in this paper. Results The review of literature revealed that the radon exhalation rate in porous uranium bearing rocks is less affected by the ore grade than in non-porous rocks. The exhalation of radon from backfill tailings is quantitatively more significant than from the uranium ore itself due to higher bulk porosity and enhanced surface area. Thus, porosity is the dominant factor that affects the rate of radon exhalation from rock surfaces into mine openings. Practical implications The knowledge of the sources of radon and quantitative estimation of radon from various sources will be very much useful in the planning and designing of ventilation systems in underground uranium mines. The accurate measurement of radon exhalation in underground uranium mines can be made by choosing the optimum size of accumulation chamber and a suitable radon build-up period in the chamber. Originality/value The study portrays the important sources of radon and its measurement techniques in underground uranium mines based on an extensive literature review. The methods of measurement of radon exhalation from the ore body and backfill tailings in underground uranium mines, used by the authors of this paper, comparatively give more accurate results than previously used methods. Furthermore, the methods are more effective in terms of portability, cost and time for measuring the average radon exhalation across a large.

Multivariate regression analysis to assess the 222Rn exhalation rates from uranium ores and their relative contributions to the 222Rn concentration in the underground uranium mine atmosphere

Multivariate regression models involving radium (226Ra) content and porosity to fit surface and mass radon (222Rn) exhalation rates from uranium ores were established in this paper. This paper also presents the contributions of the orebody and broken ore piles to the 222Rn concentration in an Indian underground uranium mine. Statistical regression models explained 94% of the variation of the radon exhalation rates. Based on a statistical analysis of data, the porosity was considered as one of the significant parameters influencing the 222Rn exhalation rates from uranium ores. This study revealed that the surface 222Rn exhalation varied from 0.0112 to 0.735 Bq/s per m2 with the geometric mean of 0.0884 Bq/s per m2. The mass 222Rn exhalation rate varied from 0.92 to 46.94 Bq/h per kg with the geometric mean of 6.58 Bq/h per kg. The total contributions of the orebody and broken ore piles to 222Rn concentrations were about 6% of the lower workplace reference level stipulated by the regulatory body. It revealed that the orebody and broken ores were not prominent for the radon concentration level under the existing mine ventilation system.

222Rn dose of mine water in different underground uranium mines

This paper describes the method for estimation of the contribution of mine water to 222Rn dose and its health risk using smart radon monitor with bubbler kit in Indian underground uranium mines. A significant positive correlation between 222Rn release rate and the water flow rate was also established in this paper. The geometric means of 222Rn doses in Mine 1 and Mine 3 were found to be 2.3 μSv y−1 and 9.6 μSv y−1, respectively. The arithmetic means of 222Rn doses in Mine 2, Mine 4, and Mine 5 were found to be 4.9 ± 4.0 μSv y−1, 27.1 ± 20.2 μSv y−1 and 13.7 ± 2.6 μSv y−1, respectively. The mean values of 222Rn doses in the above mines were well below the limit value of 100 μSv y−1 reported by the European Council. The average values of excess lifetime cancer risk (ELCR) in the mines varied from (5.9 ± 1.1) × 10−3 to (70.0 ± 53.3) × 10−3. The mean 222Rn-induced lung cancer cases per year per million persons (RnLCC) were found to be far below the limit range of 170–230 × 10−6 recommended by the International Commission on Radiological Protection. Therefore, mine water was found to be less contributor to the 222Rn dose in underground uranium mines.