| A Besides contain demanded mineral component, associated mineral also associated some natural radioactive material which exceeds standard rate. In the processes of exploit, refining, machining and utilized, these natural radioactive materials contained in associated mineral will be migrated, concentrated and diffused, the product and waste which contains natural radioactive nuclide will also lead radioactive pollution to the environment and public in some degree.Xinjiang is rich in mineral resources, there is mainly lignite, long flame coal(anthracite), non stick coal(bituminous coal), coal etc. Recently, according to large investigation and monitoring by Xinjiang radiation environment supervision and monitoring department. It′s said that coal in Xinjiang Ili area associated with higher content of natural radionuclides. In this paper, we were mainly to investigate the associated radioactive substances in coal resources inan mining area. We have investigated radon concentration in the coal mines which has been mined, and the radionuclide content of 238U、226Ra、232Th of mine water samples, γ-radiation dose rate, coals, Ash(residue) samples and gangue samples. We have also investigated radionuclide content of U、Th of drilling core samples in mines which was untapped minefield. Research result shows that:(a) γ-radioactive dose rate at grass are all on the same level as the locality, the dose rate in each mine is also on the same level as the locality except Mr Zazi sun niru township, Yi ore and Gram figure buick township coal mines.(b) The radionuclide content of 232 Th of mine samples in each mine ison the same level as the locality. The radionuclide content of 238 U and 226 Ra in Xinwen No.1 coal mine, Wu kool it, Yi Zhao, Ng Tung, Media Tek, Mr Zazi sun niru township coal mines belong to immunity regulation in DB65/T 3471-2013 "The coal resources exploitation of natural radionuclides Limited". The radionuclide content of 226 Ra in Yi ore coal mine, the maximum radionuclide content of 238 U and 226 Ra in Tara di, Tick A Zek,Gram figure buick township coal mines are more than then the level of locality, and the specific activity is more than 100 Bq/kg, which belong to limited regulation in DB65/T 3471-2013.The grade of natural radioelement U in Ili No.1 shaft area and the eight coal seam of No.2 shaft area approximates to 0.010% and 0.014% respectively.(c) Total α and β concentration activity of mine water influx samples in coal mines which has been mined is lower than the standard in "integrated wastewater discharge standard".(d) The research, which is on the basis of the survey about environment radiation level in the Southern Ili Yining mining area and combined with monitoring survey data,has assessed the emission level of radon and dust in roadway and dump by using theoretical formula.It has also obtained the value of aerosol nuclide.(e) The research has calculated the atmospheric disffusion factor between different distance points by using atmospheric dispersion model.It not only has estimated individual effective dose of the public caused by Rn-222 emissions and dust emissions, but also has concluded the effective dose of public in different places caused by mine radon and radioactive dust in the southern of Yili mining area according to the report NO.19 by IAEA.The highest individual dose in all of mines except of Ili No.2,is less than 0.1m Sv/a outside 400 m away of mining area.The effective dose of public in area 200 m,400m and 800 m away from Ili No.2 is 0.74 m Sv/a、0.22 m Sv/a and 0.15 m Sv/a,all of them is more than 0.1m Sv/a.The main reason is that U grade in the eight coal seam of mining area is higher( reach the level of In-situ leaching uranium mining).(f) The main radiation hazards to staff are inhalation of radon and its daughters and external gamma irradiation of exposed wall in mines. The results show that the public effective dose and staff doses were below the dose constraint value in all mines except Ili No.2 shaft area. |
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