The previous studies of Mengqiguer uranium deposit centred on the directing exploration work and summary of metallogenic regularity. There are few studies on groundwater hydrodynamic field in upstream and downstream of the mining area affected by in-situ leaching. It is found that the linkage between groundwater level and seasonal variation is not obvious in the process of uranium exploration outside the mining area. These changes are quite different from the understanding of the natural flow field of groundwater in the previous exploration process. Previous studies have shown that the groundwater level throughout the deposit varies seasonally. In view of this, this paper analyzes the influence of in-situ leaching mining on the groundwater system of Mengqiguer deposit by collecting the hydrogeological data in the exploration stage and the actual measurement. Through the analysis, it is concluded that the upstream of the in-situ leaching mining area is not affected, the underground water level in the mining area is slowly declining, and the underground water level in the downstream of the mining area continues to decline. This study can provide a new idea for the understanding of groundwater hydrodynamic field in the process of uranium exploration outside the mining area, and also provide data reference for in-situ leaching of uranium.

Taking the stope of a uranium mine as the research object, based on the characteristics of the ore body and existing engineering experience, the upward horizontal slicing mining method is selected. The mining scheme model with different stope structural parameters is established by using the numerical method of FLAC3D. Through the numerical simulation of the stope mining and backfilling process, the temporal and spatial evolution characteristics of the stope stress field, displacement field and plastic zone are analyzed. The stability of stope is studied. The results show that the horizontal stratified height of 2 m is safer and more stable than 4 m, especially in the early mining period. With the development of mining operations, the stress concentration area of the stope gradually expands, and there are obvious stress areas through the top and bottom of the mining area. With the progress of backfill, the distribution of compressive stress inside the backfill body is more uniform, showing a small compressive stress, and the stress change amplitude is not large in the later period. The displacement at the intersection of roadway and stope is the largest, and in the early stage of mining backfill operation, the growth rate is fast and the near-vertical jump growth occurs. The displacement changes at the middle part of roadway and the top plate in the middle part of stope show phased changes, and the overall displacement is small.

Based on the efficiency of uranium extraction drilling, a new type of cut-window drilling was developed. The advantages and disadvantages of two different drilling structures were analyzed by comparing the site construction and leaching effect of gravel filling drilling and cut-window drilling. The results show that the construction quality of cut-window drilling is controllable, the drilling operation stability is long, the leaching effect is good, the uranium concentration in the leachate rises quickly, and the recovery rate is high. The comparative use of the two structures provides important theoretical basis and practical application experience for the mining of uranium mine, and the cut-window drilling is helpful to improve the exploitation and utilization of uranium resources.

Acid concentration and uranium concentration in raffinate phase generally need to be measured separately, which is cumbersome and requires a large amount of work. A new method for continuous measurement of acid concentration and uranium concentration in raffinate phase was developed. A strong base was used as titration agent, the color change of the indicator was selected to indicate the titration endpoint. After completing the acid concentration detection, the sulfuric acid and arsenazo III solutions with a certain amount and concentration were added to the above solution to make the solution color, and the absorbance of the color solution was measured at 650 nm. The results show that the precision of measuring acid concentration and uranium concentration is 1.53% and 1.13% respectively, the indication error for measuring acid concentration and uranium concentration is 1.69% and 1.52% respectively. For the measurement of actual water samples, the measurement data of this method is basically consistent with that of the laboratory current methods, the recovery rate of acid concentration measurement is between 97.0% and 102.5%, and the recovery rate of uranium concentration measurement is between 97.0% and 102.0%. The method is suitable for continuous monitoring of acid concentration and uranium concentration in raffinate phase and has accurate and fast characteristics.

Investigation on release characteristics of radon concentration, radon release amount, migration and diffusion trend of radon of an acid in-situ leaching uranium mine was carried out on the basis of data collection and field investigation. This study monitored radon concentration of source items and surrounding environment on uranium milling plant vents, leaching tanks, evaporation ponds and recovery wells with adoption of E-Perm electret detector, solid track detector and RAD7 radon detector. The results show radon concentration level is highest at top opening of leaching tanks, nevertheless affected area is no more than 500 m. Lowest radon concentration appeare at point of recovery wells. The annual total radon release of the acid in-situ leaching uranium mine is about 1.75 TBq/a, milling plant and leaching tanks are important radon release source items, which accounte for 58% and 39% of the total radon release respectively, additionally radon release of recovery wells and evaporation ponds account for 3% of the total radon release. In summary, the normalized annual radon release amount of the acid leaching uranium mine is much smaller than that of underground mine exhaust shaft.

Bayinqinggeli uranium deposit in the northern of the Ordos Basin is hosted in the lower sub-member，lower member of Zhiluo Formation，with an average uranium grade of 0.057 1% and an average uranium mass per square meter of 6.69 kg/m²，but its permeability coefficient is only 0.065 m/d，which is a typical low-permeable sandstone uranium deposit. For this deposit，the well Z5，which has poor injection capacity，is selected to carry out the high energy gas fracturing experiments. The uranium deposit aquifer of the well is located at 619~639 m，and the depth of the propellant is placed at 632.5~637.4 m，626.6~631.6 m，620.6~625.6 m. The amount of the propellant is 40 kg for each time. At the same time of fracturing，microseismic monitoring is carried out around well Z5. There are 59，61 and 49 events generated by the fracturing of three times，and the event profiles show that the fractures formed in the reservoir are trending at 46.8°NW，31.0°NW and 72.3°N，respectively. After fracturing，the injection volume of well Z5 is significantly improved，with an increasement of 126.34%. The high energy gas fracturing can improve the permeability of the near-well area. It is easy to implement and the cost is low.

In response to the problems of high cost and low reuse rate of wired networks, small coverage range and high interference of wireless networks, the in-depth research was conducted on the existing network system in uranium mines, and demand analysis was carried out based on the actual needs. With the goal of full coverage of wireless local area networks for signal wireless transmission, positioning, and remote monitoring of underground personnel and equipment, and on the basis of unified network transmission protocol, the applicability of wireless network transmission technologies such as 5G and Wi-Fi was analyzed. Suitable equipment and working frequency bands were selected, and a network testing platform was built for wireless signal transmission rate and delay experiments to verify the applicability of underground wireless technology applications. The result can guide the construction of underground networks in uranium mines and provide reliable network support for underground production equipment monitoring, environmental monitoring, positioning, communication and important data transmission.

A method for simultaneous determination of As and Hg in uranium ore by hydride generation atomic fluorescence spectrometer was established, and the effects of digestion temperature, digestion time, medium system, KBH₄ concentration, and uranium content on the detection results were investigated. The results show that the optimal conditions for this method are to dissolve uranium ore with (1+1) aqua regia for 60 minutes at 125 ℃, (5+95)HCl as the medium and 2.0% KBH₄ solution as the reducing agent. The detection limits of this method are 0.006 μg/g (for As) and 0.001 μg/g (for Hg), with relative standard deviations of 2.46% (for As) and 4.22% (for Hg), and recovery rates of 98%~103%(for As) and 97%~106% (for Hg). This method has high accuracy and precision, and can meet the requirements for the determination of As and Hg in uranium ore.

Blockage of ore bearing layers is the most common technical problem in in-situ leaching of uranium. A certain experimental mining area has been operating for about 200 days, and the injection pressure of the injection well has increased to 1.65 MPa, and the average injection flow rate has decreased by 51.87%, and serious blockage has occurred in the surrounding ore-bearing layers. The calculation shows that when the natural flow field conditions are transformed into the leaching flow field conditions, the groundwater flow velocity can be rapidly increased by tens to hundreds of times. Hydraulic erosion is the dynamic condition for the migration and precipitation of debris in the ore-bearing layers around the pumping well. The mineral debris and chemical precipitation carried in the leaching solution, which are retained in the tail liquid after surface filtration and resin bed adsorption, are re-deposited and accumulated in the ore bearing layer around the injection well, which is the direct cause of its blockage. During the research period, mechanical blockage was the main factor, accompanied by chemical precipitation blockage. Based on the research results of the maximum pore throat diameter of previous ore bearing layers, combined with underground television observation, the particle size of the leaching solution, well washing water, and the chemical composition analysis of the settling dry residue of the well washing water, it is determined that the mineral debris is mainly clay powder sand particle level debris, and the chemical precipitation is mainly CaCO₃, MgCO₃, Fe(OH)₃, with a small amount of FeCO₃. For this reason, with the goal of “preventing blocking”, a hydrocyclone separator has been added. The surface solid-liquid separation system coupled with “natural sedimentation-hydrocyclone separation-mechanical screening” has achieved obvious results, which is expected to be popularized and applied after further research.

For the salicylic acid chelating resin, the specific surface area and pore size were determined using low temperature nitrogen adsorption-desorption method; and its thermodynamic stability was examined. The effects of solution pH and ρ(Cl^-) on its uranium adsorption performance were studied, and its adsorption isotherms, adsorption kinetics, and desorption performance were also investigated. The results show that the specific surface area of salicylic acid chelating resin is 32.34 m²/g, and the pore size is 32.08 nm, The salicylic acid chelated resin has good thermal stability when the temperature is below 180 ℃. When the pH is in the range of 7~9, the resin has good adsorption performance, and the uranium adsorption capacity can reach 14.1 mg/g dry resin. The presence of Cl^- can reduce the adsorption capacity for uranium. When the ρ(Cl^-) is 3.0 g/L, the uranium adsorption capacity decrease by about 9.2%. When the equilibrium ρ(U) in solution is 400 mg/L, the uranium adsorption capacity of the resin reach its maximum, at 153 mg/g dry resin. After 20 h adsorption, the adsorption process reach equilibrium. Both acidic and alkaline desorption agents show good desorption performance for resins, with desorption rates both above 94%. For the real uranium leaching solution with ρ(U) of 21.2 mg/L and ρ(Cl^-) of 3.36 g/L, the uranium adsorption capacity of the salicylic acid chelating resin can reach 14.7 mg/g dry resin after 24 h adsorption, indicating good uranium adsorption performance.