Radioactive geological environment investigation and evaluation of a coal field on southwest edge of Ordos Basin

Radioactive elements exhibit both chemical toxicity and radioactivity. During the development and utilization of coal resources, radioactive elements that may exist in coal seams can cause radiation pollution to the geological environment of the mining area and its surroundings through processes such as migration, decay, and diffusion, thereby impacting human health. Therefore, it is necessary to conduct investigations and evaluations of the radioactive geological environment in certain coal fields that may be subject to radiation pollution, based on actual research findings. During the project implementation, radioactive anomalies were discovered in multiple exploration boreholes within a coal-bearing rock series located on the southwestern edge of the Ordos Basin. This suggests that there may have been radioactive radiation pollution during the mining process in this coal field. To further clarify the impact of radionuclides on the geological environment during coal mining, techniques such as measurements of environmental terrestrial gamma radiation dose rates, radon concentration assessments, and sample testing were employed to conduct an investigation and evaluation of the radioactive geological environment in the study area. The analysis of gamma radiation dose rates and radon concentrations indicates that coal mining in the study area has minimal overall impact on the radioactive geological environment of the mining area and its surroundings, falling within the category of exemption from supervision. Additionally, based on the results of sample testing, a radioactive evaluation of the main environmental impact factors in the study area was conducted. The evaluation results reveal that waste generated from coal development and utilization, such as coal ash and slag, poses potential radioactive pollution and cannot be used as primary building materials or as Class A and B decorative materials. It can only be used as Class C decorative materials for building exteriors and other outdoor applications. The levels of radioactive pollution in the coalfield and surrounding soil are considered acceptable. Coal mining has little impact on the radioactive environment of the surrounding soil and sediment, and the radioactive hazard to residents is within a safe range. Furthermore, the wastewater discharged during coal field development shows no radioactive pollution to regional surface water and groundwater; however, this water should not be directly used as a drinking water source.