中国地下煤矿^(222)Rn和^(220)Rn水平的初步调查研究

PRIMARY INVESTIGATION AND STUDY ON ^(222)Rn AND ^(220)Rn LEVELS OF UNDERGROUND COAL MINES IN CHINA

本文介绍在2002年12月至2004年8月期间,用固体径迹探测器对北京史家营矿、房山城关矿、山西古交西曲矿、太原王封矿、湖南衡阳市柏坊矿、衡南县松柏矿、贵州黔西红林矿及浙江安仁锦江矿等5省市的8座煤矿井下氡浓度进行了实际为期1年(分四个阶段)的调查。结果表明,8座煤矿的年平均氡浓度(测点数)分别为550(69)、3 187(28)、45(224)、117(72)、88(79)、79(58)、40(72)、136(116)Bq/m3。井下氡浓度及其变化规律与通风状况、地质结构等因素有很大的关系,通风不好的矿井氡浓度较高,且呈现出夏、秋季高,冬季低的趋势;而通风状况良好的矿井氡浓度较低,且四季变化不明显。结合调查结果揭示了北京地区煤矿氡浓度普遍较高、浙江石煤矿并不太高以及国有煤矿较低等一些特点,对影响煤矿井下氡浓度水平的因素作了简要分析。文中还给出了北京和湖南两地所测煤矿井下220Rn及其子体水平的测量结果,220Rn子体α潜能浓度与氡子体α潜能浓度的比值在0.036~0.42之间。

From Dec. of 2002 to Aug. of 2004, by using Solid State Nuclear Track Detectors （SSNTDs）, the ^222Rn concentrations of 8 underground coal mines, i. e., Beijing Shijiaying, Beijing Fangshanchengguan, Shanxi Gujiaoxiqu, Shanxi Taiyuan Wangfeng, Hunan Baifang, Hunan Songbai, Guizhou Honglin and Zhejiang Anrenjinjiang, respectively, had been measured during a period of 12 months （ once a three-month）. The surveyed data showed that the annual average ^222Rn concentrations （with number of measuring points） are 550（69） ,3187（28）,45（224）,117（72）,88（79）,79（58）,40（72） and 136（116） Bq/m^3, respectively. The ^222Rn concentrations of underground coal mines vary with ventilation condition, geological structure and other factors, and the ^222Rn concentration in the mine with bad ventilation is generally high, and varies with seasons i.e., higher in summer and autumn and lower in winter. The ^222Rn concentration in mines with good ventilation is generally low and no notable variation with the season. There are also some characters of ^222Rn levels in Chinese coal mines, such as the ^222Rn concentrations in state-rim coal mines are general low, but those in Beijing aera are very high, and those in Zhejiang rock coal mines are not so high as expected, etc., the possible reasons have been discussed in the paper.The ^220Rn leveals of 4 coal mines in Beijing and Hunan were also measured, the ratios of alpha potential energy concentration of ^220Rn daughters to that of ^222Rn daughters are between 0.036 and 0.42.