In the stage of in-situ leaching uranium test, production and groundwater remediation, due to the selected indicators are not appropriate, the wrong judgments on the original state of groundwater, metal leaching conditions, redox environment, solution leakage, leaching range control etc. are often caused, which lead to ineffective control measures or worsening of existing problems. Based on the environmental characteristics of acid leaching, CO₂+O₂ leaching and groundwater remediation, the indicators such as U, electrical conductivity, TDS, pH, Eh, , in the leaching solution are analyzed, and the indicators that should be selected in different leaching environments, or in the groundwater remediation and stabilization periods of decommissioned mines are proposed in combination with examples. The practice has proved that the recommended indicators can truly reflect the leaching environment and groundwater remediation effect, and can provide a strong evidence for the government to formulate groundwater remediation indicators.

The high-level underground research laboratory (URL) is not only a test facility used to understand the deep geological environment and crustal stress, obtain deep rock and water samples, and verify the long-term performance of engineering barriers in the real deep geological environment, but also an important means to develop and verify the construction, backfilling and sealing technologies of the repository. It is an essential platform for the research and development of high-level radioactive waste disposal technology. In order to reduce safety risks in the operation of URL, by analyzing factors such as the engineering characteristics, spatial structure, and personnel distribution of URL, and in response to potential safety risks in URL, a study was conducted on the design of emergency evacuation facilities for URL. Through research, rescue chambers were identified the location of the mobile rescue capsule and the disaster avoidance route of the URL have been developed, and emergency plans have been developed for the safe operation of the URL under disaster conditions.

According to the water quality characteristics of fluorine-containing mine water in a uranium mine, the size of structures and key equipment, hydraulic conditions and other parameters were designed and calculated to achieve the purpose of strictly controlling the dosing amount, the flow rate of mixing facilities and the total head loss, the velocity gradient of flocculation tank, the Reynolds Number of sedimentation tank and other process parameters, so as to maximize the flocculation and sedimentation effect. Based on the operation cost and water quality monitoring data of the project in the first year, the existing problems and presented improvement measures were summarized.

Regular scientific testing and evaluation of the quality and safety of uranium decommissioning and treatment engineering facilities is an important activity to make up for engineering defects and continuously improve treatment measures, which will ensure the long-term effective isolation of uranium mine radioactive waste residue from the ecological environment. The study used on-site observation, in-situ strength detection, concealed engineering detection and other methods to complete the inspection of the structure of the decommissioning and treatment engineering facilities of some uranium mines in China that had been completed for 20~30 years, and established the quality assessment method of decommissioning treatment facilities through the investigation and analysis of the causes of damage. The results of structural inspection and evaluation show that the quality of decommissioning treatment facilities is good, the resistance to the influence of natural stress is guaranteed, and it is necessary to carry out continuous and active monitoring work. It also puts forward suggestions for future decommissioning design, construction and management.

The research area is in the slope zone of the east Ruhuhu Basin. The sand body of Ruhuhu Basin is very thick and well developed, and possess the space condition of forming the inter layer oxidation zone. There exists the dual structure in Ruhuhu Basin. The geology survey shows the characteristics of stratum, lithology and structure, and γ gross survey targets some anomalies. By the gamma spectrometry survey and surface engineering, the W-1, W-2, W-3 and W-4 are determined as the favorable areas. The Ruhuhu Basin has a huge potentiality of formed medium and large scale sand-type uranium deposits.

Uranium (U) can be readily adsorbed and retained in plant roots. A high concentration of U causes phytotoxicity. Plants have evolved a number of defence strategies operate separately or cooperate with each other to alleviate U-induced phytotoxicity. The defense mechanisms of plants in response to uranium stress were summarized, including compartmentalization, chelation of plants, antioxidant system, chemical form conversion of uranium. The related research direction was also prospected. The results are helpful to clarify the molecular genetic basis of plant tolerance to uranium and provide reference for plant response to uranium stress.

In order to improve the cutting efficiency of deep and tight ore beds, the conventional cutting technology and screw motor composite cutting technology were studied by using the ISL wells in Bayinqinggeli deposit in the northern Ordos Basin, and the application parameters of screw motor composite cutting technology were obtained. The results show that the cutting speed of screw motor composite cutting technology is 102.8% higher than that of conventional cutting technology, and the cutting quality can meet the requirements of the ISL. The screw motor composite cutting technology has wide application prospect. According to the cutting effect in research area, it is suggested to introduce screw motor with centralizer, design a new cutting tool, and establish the corresponding casing cutting procedures to further improve the cutting quality.

Aiming at the problems of poor roadway stability and difficulty in forming in the conventional mining process of soft sandstone-type uranium deposit, the similar simulation test were carried out. The fine sand, the barite powder, the swelling soil and the 425 normal portland cement were selected as the raw materials. The similar material tests with different material ratios were carried out by the orthogonal experiment. Finally, the similar materials close to the physical and mechanical parameters of the ore rock were obtained. The similar material ratio is as follows: the mass ratio of lime to sand is 1∶8, the m(barite powder)∶m(sand) is 20%, the m(bentonite)∶m(sand) is 8%, and the particle size of fine sand is less than 2.00 mm. The key factors of similar materials such as the density, the compressive strength and the tensile strength are close to the ore rock. The error rates are controlled within 7%. The results of the similar material ratio can meet the requirements of the similar simulation test. The soft sandstone similar material obtained in this test can provide basic material for similar simulation test of the roadway excavation and support.

The cycle Ⅶ of a deposit is suitable for low sulfuric acid concentration leaching. The rapid acid consumption obtained from the ore agitation leaching test is characterized by step with the increase of acid concentration of leaching agent. The change of uranium leaching rate and mineral dissolution corresponds to acid consumption step characteristics. High acid consumption step can cause CaSO₄ precipitate. The corresponding acid concentration of each acid consumption step respectively guides the selection of acid concentration of leaching agent for acidification stage, formal leaching stage, and prevent the lower permeability of ore bed. The method of definition the acid concentration range of the liquid injection was further verified by field test.

In order to recover uranium from uranium-beryllium flotation tailings and reduce the content of beryllium in uranium products, the occurrence state of uranium and beryllium in uranium-beryllium flotation tailings was analyzed by process mineralogy, and uranium was leached by sulfuric acid leaching process. The effects of acid concentration, leaching time, leaching temperature and liquid-solid ratio on the leaching rate of uranium and beryllium were investigated, and the feasibility of recovering uranium from leaching solution was studied by anion exchange resin. The results show that the uranium in the uranium-beryllium flotation tailings is more easily leached by sulfuric acid, but the beryllium is not easily leached, the uranium can be recovered and the uranium-beryllium can be separated by ion exchange method.