2.4.2.1 State of Production

Because the uranium industry plays a unique role in China's economy, all the enterprises engaged in uranium production are solely owned and managed by the State.

When entering the 1980s, China's uranium industry started a new historical stage. A number of adjustment and reform measures have been taken to cater to the demand of national economy, which has resulted in changes and advances in this sector.

In the past 20 years, uranium production has been oriented to the demand of nuclear power generation in China, following the guideline that "native uranium shall be produced domestically". At the initial stage of nuclear power development, the demand for uranium was small, so that from 1985 to 1994, some low-efficient mines and hydrometallurgical plants were successively shut up, and the annual production quota was reduced. Beginning from 1980, China started to export uranium products. To meet the demand for its use as a nuclear fuel, the quality of the products has reached the standard of "nuclear power pure".

All the uranium plants and mines are striving to be competitive in the world market by improving technology and management and using new scientific achievements and equipment.

To cater to the increased demand for uranium by the end of the century, three mining-milling complex enterprises, Yining of Xinjiang, Lantian of Shaanxi and Benxi of Liaoning, went into operation one after another in the early 1990s. They have managed to raise the economic benefit remarkably by using new technology and improving management.

While making adjustment of uranium production and increasing the efficiency, the working staff in the plants and mines have been reduced, and development of non-uranium products and industries was made by using the laid-off workers and spare facilities. In 1984 there were 45,000 people engaged in uranium production, which reduced to 8,500 in 1998. The present average productivity has increased by four times as compared with the early 1980s.

Openpit and underground mining methods are generally used in uranium mining in China. The annual production of openpit ore once made up 30% of the total production. Underground mining consists of mainly horizontal cut-and-fill stoping, making up 60% of the total underground production; secondly the sublevel caving, shrinkage stoping, open stoping and advancing methods. For coal-type uranium mines, the inclined layered filling method is used.

In the past 20 years China has paid special attention to the in-situ leaching technique for uranium mining. The Yining Uranium Mine, which went into operation in the mid-1990s, has a capacity of producing 150 tons of uranium a year, which is expected to reach 400~500 tons in the near future.

The ores in the Lantian Uranium Mine of Shaanxi have good leaching properties of uranium. Using the experience of the Chongyi Mine of Jiangxi as reference, it was built into a mine fully engaged in heap leaching production in the early 1990s. Later on, it succeeded in experimental researches of in-place leaching following blasting, which was used for production.

The Benxi Uranium Mine (Liaoning) built in 1996 used full-hydraulic rock drilling and trackless haulage equipment, and later developed mine trucks and service vehicles to go with the excavation, loading and hauling equipment of small mines. New technologies such as concentrated acids£¬ferric-sulfate infiltration heap leaching were used.

The successful applications of different heap leaching techniques to various mines have resulted in reduction of production cost, and meanwhile development of leaching technology adaptable to China's uranium mines. At present, the uranium products produced by heap leaching account for about 50% of the annual production.

The mining and milling of uranium must meet the requirements of the national standards for radiation and environmental protection. Therefore, differing with the ventilation in other mines, that for the uranium mines should aim at minimizing the retention of radon and radon daughters. The limit for radon concentration is 20 mJ/a. Meanwhile, measures should be taken to keep from the impacts of dust and radioactive airborne particles. To protect the workers of the mines, the work places are required to have radiation surveillance. The workers work 36 hours a week, and are asked to take a bath after work until they meet the personal dosage limit.

For the environmental protection in the uranium mines and mills, the most important thing is to solve the problem of radiation pollution and improve the management of retired mines and mills.

The air ventilated from the mines contains uranium dust, radon, radon daughters, airborne particles and other gaseous pollutants. The ventilation wells or other radiation sources should be kept at certain distances from the production facilities and dwelling districts at according to the Regulations for Radiation Protection in Uranium Mines and Mills.

The potential impacts caused by the effluents produced in the milling plants are much greater than those discharged from the mines. For a uranium complex, the effluents from the mine can be processed in the milling plant, whereas for a mine engaged in mining only, a processing facility is required to build up. The effluents produced in the milling plant are partly recycled, and the remaining is pumped to a tailing pond after being neutralized with lime. The tailing water is discharged after radium is removed with pyrolusite and barite.

The tailing slurry from the mills is neutralized with lime first, and then pumped into a tailing pond for permanent storage. The waste rocks and tailings should be backfilled into the underground or openpit mines as far as possible. Residents living close to a tailing pond should be moved out.

An assessment of China's radiation environment quality for the past 30 years indicates that the effective dose equivalent affecting the critical group of residents is below 5 mSv/a, the national standard set in the Radiation Protection Regulations (GB8703~88).

The aim of the management of uranium geological and mining facilities is to provide reliable protection for ecological environment and public health through appropriate disposal of the polluted facilities as well as the waste rocks and tailings. In the past ten-odd years,several tens of mines and mills have retired and started to work on the environmental control. Among them, five have completed the work, while most of the others are making preparations for the management. Meanwhile, a lot of experimental studies are made and standards and regulations being formulated, which greatly promoted the work.

2.4.2.2 Distribution of Production

There are obvious changes in the distribution of uranium production after the adjustments were made. A large number of mines and plants have been shut up. Consequently the enterprises are relatively concentrated in Jiangxi, Guangdong and Zhejiang provinces, which used to scatter in over 10 provinces (regions). In recent years three new enterprises have been built in Xinjiang, Shaanxi and Liaoning. The total production by processing plants spread out in many provinces obviously surpassed the mining capacity. Now that some plants such as Hengyang and Xifeng have shut up their production lines, and Renhua Uranium Plant also reduced its production, mining and milling have come to a balanced state. The major enterprises of China are shown in Fig. 2.4.2.

To meet the demand of nuclear power generation, the technology and standards for uranium production have been adjusted. Plants scattered all over China are arranged to produce low-U and inpure diuranates, which are purified into pure uranium dioxides by the Hengyang Uranium Plant alone, thereby improving the production efficiency and economic benefits. To meet the requirements of the world market in morphology and quality standards of uranium products so as to export uranium products, national standards for two products, "uranium ore concentrates" and "uranyl ammonium tricarbonate", were released in 1998.

The Hengyang Uranium Plant is a regional plant engaged in uranium ore processing and purification. As most of the nearby mines are shut up because of depletion of resources, only a production line for purification is retained, which has been updated to meet the demand of nuclear power generation. The Fuzhou Uranium Mine in Jiangxi is an enterprise based on the Xiangshan ore field, capable of processing 200£¬000 tons of ore and producing 300 tons of uranium per year. The Chongyi, Lantian and Benxi mines have an annual production capacity of 100 tons of uranium each. Production of the Yining Uranium Mine has been increasing in recent years, and a new project for an annual production of 100 tons is being constructed on the present basis of 100~150 tons of uranium per year.