The environmental risks and hidden dangers of decommissioned uranium mining and metallurgy facilities were elaborated. Based on analyzing the important connotation and role of long-term monitoring of decommissioned uranium mining and metallurgy facilities in China, the overall plan and implementation approach for long-term monitoring were summarized. In response to the current situation and problems in long-term environmental monitoring of decommissioned uranium mining and metallurgy facilities in China, the solutions and methods have been proposed, and the attention has been given to the technical and management measures for subsequent operational monitoring work.

The static and dynamic adsorption behavior of porous silica gel on uranium in high fluoride solution was studied, the feasibility of the application of silica gel adsorption and uranium removal technology in the treatment of high fluoride radioactive wastewater was explored, and the influence of various adsorption conditions was verified. When ρ(F^-) in the solution reaches 100 g/L, the static adsorption capacity of porous silica gel for uranium is 31~33 mg/g, indicating that the high fluoride environment has a small impact on the adsorption of uranium by porous silica gel and has a high selectivity for {\mathrm{UO}}_2^{2+} and F^-. The static adsorption test shows that the best adsorption effect for uranium is achieved when the radioactive wastewater pH=8~9. The dynamic adsorption test shows that when the pH of radioactive wastewater is 9, the working capacity of the porous silica gel adsorption column is about 20 times the column volume. Most of the uranium in the adsorbed silica gel column can be desorbed by 1 mol/L HNO₃, with a capacity of about 10 times the column volume. The porous silica gel column was desorbed with 1 mol/L HNO₃ eluent and reused 5~6 times, with the basically same penetration curve position for uranium.

The standardization construction of safety production is of great significance for the safety production management of units. In order to explore the influencing factors of safety production standardization construction in a certain geological exploration group, the entropy weight method was used to analyze the safety production standardization evaluation results of its four subordinate units. The results indicate that emergency management, continuous improvement, inspection and maintenance, production site and process, occupational health, and safety warning signs are the key influencing factors that need to be focused on in the construction of safety production standardization in the geological exploration group. Improvement suggestions are proposed to address these influencing factors.

The electromagnetic radiation environment of 750 kV single cycle parallel transmission line was calculated and predicted by adopting the calculation model recommended by Appendix C and D of Technical Guidelines for Environmental Impact Assessment of Electric power Transmission and Distribution (HJ 24—2020). The results show that when the minimum height to ground of the conductor passing through farmland, garden land, pasture land, livestock and poultry breeding land, roads and other places is 15.5 m, the maximum value of the power frequency electric field intensity under the single cycle parallel line is more than 10 kV/m, the minimum height to ground of the conductor needs to be elevated to 16.5 m to satisfy the limit requirement of 4 kV/m. The power frequency magnetic field generated by the 750 kV single cycle parallel transmission line is less than the public exposure control limit(100 μT), which generally will not be an environmental constraint for the construction of the line, however, the power frequency electric field generated by the line is the main factor of the electromagnetic environmental impact, and the control limit of the power frequency electric field strength(4 kV/m) is an environmental constraint for the construction of the line, and it is also a key control factor for the electromagnetic environment of the transmission and transformation power. The field measurement results and the theoretical prediction results are in good conformity, indicating that the prediction model used has good applicability, and the results of the study can provide technical support for the construction and environmental supervision of 750 kV single cycle parallel transmission lines.

Geostress measurement is a necessary prerequisite for determining the attributes of engineering rock body mechanics, analyzing the stability of the surrounding rock, and realizing the scientific excavation design and decision-making of rock engineering. With the depth of mining of Mianhuakeng mine, the impact of complex structural stress on the stability of the lane roads and lying surrounding rocks has become increasingly apparent. In order to master the terrain distribution of the rock body in the deep part of the mine and improve the scientific, safety and economic rationality of the underground engineering design, the hollow inclusion stress relief method is used to carry out the stress measurement of the mine, and analyze its stress status and distribution rules. The results show that the maximum main stress is between 22.5 and 29.8 MPa and the ratio of the maximum main stress to vertical stress is 1.5 ~ 1.7 in the buried depth of 615~715 m. The main stress increases linearly with the depth and the maximum main stress direction of each measurement point level is in the direction of from 91.2 to 110.3° (North West West-South East East), which has a strong consistency.

Deep-hole blasting is used in the mining of hard rock uranium ore in Mianhuakeng mine, the blasting parameters are derived from the experience value of the diameter of the blasting hole, which has the problem of low blasting quality. The optimum depth and radius of 300 g charge are 0.65 m and 0.63 m respectively from the single hole blasting crater test, the optimum distance between holes is 0.9~1.0 m and its ratio to the optimum crater radius is 1.43~1.59 from the multi-hole blasting test with variable hole spacing, the optimum minimum resistance line from the slope step blasting is 0.41 m. Based on the blasting similarity law, the optimum hole spacing of 65 mm deep hole is calculated to be 1.7 m. Considering that the test results of slope step blasting are not ideal, the empirical value of hole bottom density coefficient of fan-shaped hole layout is 1.0~1.3, and the row spacing of deep-hole blasting is recommended to be 1.3 m after calculation.

A lead-zinc mine is exploited by adit+shaft+slope path, and mined by sublevel open stope method and shallow hole retaining method. This method has large exposed area and poor safety, and the goaf formed by stope has buried hidden danger for mine production. With the increase of depth, the stability of surrounding rock becomes worse, the ore body becomes thinner and more dispersed, resulting in the increase of mining dilution rate and the extremely high mining and mineral dressing cost, and the original mining method is no longer applicable. According to the characteristics of ore body and the current production situation of the mine, the mining of the ore body below the middle level of 2 522 m adopts application of mechanized upward horizontal slicing and filling mining method, and uses large trackless equipment to carry out mining operations, which reduces the exposed area of the stope, improves the safety of underground operation, avoids a large number of goaf, solves the hidden danger in production and improves the recovery rate of resources. The production capacity, comprehensive recovery rate, comprehensive dilution rate and other indicators are optimized. The research results can be used as an example for other mines in this area.

An on-line analyzer was developed for the determination of carbonate and hydrogencarbonate concentrations in the tail liquid of a fluorine-leaching agent by titrimetry with the electrode measuring pH as the end point, the chemical principle, hardware composition, determination program and other functions of the instrument were introduced. The alkalinity of 0.01~1.00 mol/L was determined by the instrument. The repeatability error is 1.5%, the accuracy error is 4.8% and the lower detection limit is 0.04 mol/L. The results of field test show that the instrument has good stability and high precision, and the measured data are basically consistent with the on-site titration analysis data, which meets the requirements of on-site analysis. The recovery rate of spiking is between 96.0% and 104.0%.

With the development of uranium mining and milling industry, the number of uranium tailings pond is increasing. It has potential harm to the surrounding environment. Therefore, exploring an environmental and effective way to control the pollution sources is to be imminent. Uranium tailings pond covering technology is an effective method recognized at home and abroad, and is also the main technology used in most practical projects at present. The status of uranium tailings pond covering technology at home and abroad is reviewed, the common materials, technical measure, and the governance effectiveness of decommissioning uranium tailings pond are described, in order to provide reference for the surface covering engineering technology of uranium tailings pond.

As a new type of organic porous material, covalent organic frameworks are widely used in environmental field because of their large specific surface area, ordered pore structure and controllable scaffolds, such as adsorption, separation and photocatalytic degradation of pollutants. The removal of radioactive contamination in the environment by covalent organic framework-based materials is reviewed, and the research progress of removal of uranium, europium, thorium, technetium and iodine by covalent organic framework-based materials is discussed.