Study On Outdoor Radon Level In Chejiang Copper Mine

An aerial of the Hengyang 272 tailings ponds and its surrounding areas were carried out by—Ministry of Environment Protection in 2014 and it showed that there was an abnormal radiation level in a region to the western of the tailings pond and near the upper reaches of Xiangjiang river,before the area is identified as Chejiang copper mine.Due to the lack of attention paid to the radiation level of non-uranium mines?NORM?in the past,Li Yue from the university of south China conducted a preliminary survey on the radiation sources in the area only two years ago and found that the outdoor radon concentration(41±8.0Bq·m^-3)in the area was 2-3 times higher than the national average(14.0Bq·m^-3).In order to further investigate the level of outdoor radon concentration in this region and find out the source of local outdoor radon,the outdoor radon concentration and soil radon exhalation rate were investigated,and the diurnal variation rules of radon concentration and radon exhalation rate were measured to determine the correlation between them.In order to fully investigate the radon concentration level in this region,it is preferred to measure the average radon concentration in four regions of this region?residential area,tailing area,farmland covered area and original mining area?by solid nuclear track accumulation method in spring and summer?April to June?and autumn and winter?September to November?.And Hengyang nuclear industry 272 factory at close range and Chejiang copper mine,the radon concentration tailings backfilling materials landfill of uranium and lead to abnormal,affected by the monsoon,the region of radon migrated to Chejiang copper mine area,so using solid state nuclear track cumulative measurement method for the nuclear industry 272 factory?September to November?winter outdoor radon level investigation,all the samples are in accordance with the standards of environment radon measurement?GB14582-1993?.In addition,in order to investigate the regional scope of abnormal concentration of radon,radon-7 radon meter was used to conduct radon level survey in a radius of 1Km along the south,west and north directions with the Chejiang copper mine as the center at every 100m interval.Xiao Gaoping reference at the same time,south China university of uranium tailings radon years to release a quantity to reliable estimation method,active carbon in the spring,summer,autumn and winter season-gamma spectroscopy and continuous measurement of radon exhalation rate Chejiang copper mine?tail mine area,farmland covered area,the original mining area?soil radon exhalation rate were investigated,and choose the instrument for measuring radon concentration to the region to study the change rule.The results showed that:?1?The average annual concentration of radon in the whole region was?27.2±5.8?Bq·m-3,which was 1.94 times,1.53 times and 1.32 times of the national average concentration of radon?14.0Bq·m-3?,the Hunan average concentration of radon?18.0Bq·m-3?and the Hengyang average concentration of radon?21.0Bq·m-3?;?2?The outdoor radon concentration within 1km of the mining area is negatively correlated with the distance to the center of the mining area;?3?By measuring the relative distribution and continuous change of the radon exhalation rate in the region of Chejiang copper mine,the revised regional radon exhalation rate can be obtained.According to the results,the annual radon exhalation amount in the tailings area,farmland covered area and the original mining area is respectively8.51×10¹⁰Bq,1.96×10¹⁰Bq and 3.90×10¹⁰Bq;?4?According to the continuous measurement results of soil radon exhalation rate and outdoor radon concentration in the Chejiang copper mine,the change rules are relatively consistent,and the correlation test coefficient between outdoor radon concentration and soil radon exhalation rate reaches 0.97,indicating a good positive correlation between them.The results show that the high radon concentration in the Chejiang copper mine is caused by radon exhalation from the local soil.