Results 1 - 10 of 83
Results 1 - 10 of 83. Search took: 0.018 seconds
|Sort by: date | relevance|
[en] Through field research of large uranium mine development in Namibia, the advanced experience of large uranium mine development in foreign country is summarized from the aspect of mine design concept, development and construction mode and production management. By comparative study, some beneficial enlightenments of uranium mine development are put forward for Chinese uranium mine development as references. (authors)
[en] Most non-coal mine roof accident analysis is focused on man-made reasons, but other reasons are ignored. Hazard sources identification in combination of the occurrence mechanism of roof accidents are employed in this paper to identify the source of hazard at the mining area of Zoujiashan stope roof. The results show that ore body thickness, dip angle of ore body, buried depth, roof thickness ,uniaxial compressive strength, fault and big roof time are main factors of Zoujiashan roof accidents. (authors)
[en] 'Evaluation and Enlargement Enlargement Technique Study on Big Uranium Resource Base' is an special CNNC project which is an important part of technological innovation program. This paper introduced the concept of big uranium resource base and the progress and achievement in five base of Yili, Xiangshan, Dongsheng, Erlian and Southern Zhuguang. (authors)
[en] Cyclic loading damage in uranium mining is often accompanied by changes in radon exhalation characteristics. Understanding the relationship between rock damage and radon exhalation of uranium ore is therefore important for predicting rock instability and improving monitoring methods to ensure the safety of uranium mines and other underground projects. In this study, we performed constant amplitude cyclic loading and unloading tests on quasi-uranium ore to measure the degree of damage and used the closed chamber method to measure the accumulated radon concentration. The results show a range of damage values between 0.089 and 0.315. The sample with the highest damage value also showed the highest radon exhalation rate of 0.0411 ± 0.00384 Bq m-2 s-1. We use the dissipated energy as a damage variable and find a positive correlation between damage and radon exhalation rate. The damage value was fitted with radon exhalation rates, yielding correlation coefficients of 0.97, and shows an inverted S-shaped trend. The results provide a basis for monitoring rock stability using radon exhalation in future uranium mining operations. (author)
[en] The shaft and lane engineering has an important role in mine production. Reasonable programs for excavating may make drilled footage per month to be improved by a large margin. At present, there are lots of programs for excavating in every mine. Therefore, how to choose an appropriate scheme is vital. Combining the practical work experience of the mine for several years in this paper, the matching programs for rapid excavating and equipment were discussed and compared. Meanwhile, the application of the reasonable distribution third scheme was put into practice in the engineering at middle of 190 meters, and better effects were got. Therefore, it can also be acted as the reference for similar mine production. (authors)
[en] Water level and wind speed have important influences on radon release in particle-packing emanation media. Based on radon migration theory in porous media under three water level conditions, an experimental setup was designed to measure the surface radon exhalation rate of uranium tailings from heap leaching uranium mine at different water levels and wind speeds. When the water level was at 0.3 m (overlying depth 0.05 m), radon transfer velocities at the gas–liquid interface were also measured at different wind speeds. Results show that when the water level was equal to or lower than the surface of the sample, the radon exhalation rate increased with increasing wind speed and decreased with increasing water level. When the water level was higher than the surface of the sample, radon exhalation rate of the water surface increased with increasing surface wind speed. The wind speed, however, was less influential on the radon exhalation rate as the depth of the overlying water increased, with a dramatic decrease in radon release. That said, at different wind speeds, radon transfer velocities at the gas–liquid interface were consistent with literature. On the other hand, changes in wind speed had significant influences on the radon transfer velocity at the gas–liquid interface, with the effect less pronounced at higher wind speeds.
[en] After the 18th Party Congress, the Central Committee of the Communist Party put forward the concept of 'innovation, coordination, green, open and sharing' the five development ideas. The first mention of the 'implement the most stringent environmental protection system' and the 'beautiful China' was written in the 13th five-year planning, ecological environmental protection is on an unprecedented height. However, as the radioactive uranium mine, some problems existing in the development and construction of the national economic construction and the development of the contradiction between the concepts, have become increasingly prominent, which is need to be solved. Through comparison at home and abroad uranium mining safety and environmental protection status and existing gap, from the establishment of evaluation system of green uranium mining and metallurgy, carrying out the basic theory research and innovation, promotion key technology research and development as well as construction of major demonstration projects, the way to build up the green security uranium mine in China and the safeguard measures are put forward. (authors)
[en] In combination of the state new era of 'innovation, harmony, green, open, sharing' five major development concept, the main problems and the domestic situation of uranium mining enterprises are analyzed. How to construct green uranium mine construction standards, implementation way and safeguard measures are put forward. (authors)
[en] The vibratory ore drawing funnel at one uranium mine was introduced, and problems of unreasonable design, processing, installation as well as lack of standardization operation of the vibratory ore drawing funnel in the production process were analyzed also. All those problems are affected the operations safety and extraction efficiency of the ore at a certain extent. Aimed at the above problems, improvement methods for the vibratory ore drawing funnel structure was put forward and carried out. Through the practical application, the improved vibratory ore drawing funnel has made significant effect in a new stope. Therefore, the safety of operation is greatly increased, and extraction efficiency of the ore is increased about 11%∼27%. (authors)
[en] In order to study the radon release behavior when heap leaching uranium ores with dilute sulfuric acid, unleached uranium ores from a uranium mine in southern China were selected as test samples. Adopting parameters from leaching processes commonly used in uranium mines, a laboratory experiment was carried out for 21 days with a one-dimensional acid heap leaching experimental column. The surface radon exhalation rate of uranium ore column was determined by static accumulation method while spraying with deionized water and dilute sulfuric acid. The uranium leaching rate and ore column height for all 21 days of the experiment were also measured. The results show that (1) when sprayed with a leaching agent, the surface radon exhalation rate of uranium ore column initially increased with time sharply. After a maximum value was reached, the rate gradually decreased and stabilized. When the spraying stopped, the surface radon exhalation rate of uranium ore column initially decreased, before increasing until it tended to stabilize. (2) During the entirety of the 21-day leaching experiment, the cumulative leaching rate of uranium increased gradually with time. On the other hand, the surface radon exhalation rate of uranium ore column fluctuated, but the leaching of uranium from uranium ores had almost no effect on the radon exhalation rate. (3) There was no linear correlation between the surface radon exhalation rate and the residual height of ore column during leaching, but the collapsing event of ore column was the direct inducing factor of the fluctuation of surface radon exhalation rate.