Tailings dam (library) basic knowledge
After the metal or non-metal mining gold out of the ore, the ore beneficiation plants selected to produce valuable sand - kind of "waste", called tailings, our country produces about 300 million tons of tailings per year. These tailings are not only large in quantity, but also contain useful ingredients that cannot be recycled temporarily. If they are discharged arbitrarily, they will cause the loss of resources. What is more serious will be that the farmland will be covered in a large area, the river channel will be blocked, and serious environmental pollution will be caused. Therefore, it must be properly deal with.
The technique of transporting tailings discharged from a concentrator to a designated location for stockpiling or utilization is called tailings treatment. The structure system constructed for the tailings dump is generally referred to as the tailings reservoir, including the reservoir area, the tailings dam, the drainage structure and the observation equipment of the dam, etc., for storing the tailings discharged from the concentrator. China's tailings ponds are mainly concentrated in industries such as nonferrous metals, metallurgy, chemicals, gold, building materials and nuclear industries. According to preliminary statistics, about 1,500 tailings ponds of a certain scale have been formed. More than 100 million m3 storage capacity of 10 seats, the largest number 4 is tailing pond of Dexing Copper Mine, the storage capacity of 830 million m3.
Harmfulness of tailings accident
The tailings pond plays an important role in mine production and is an important facility to maintain mine production. Because the tailings pond is difficult to avoid residential areas and densely populated areas, it is also an important source of danger. When the tailings dam breaks down, the tailings tend to liquefy immediately, expand the dam's gap, and dump downstream along the valley. The damage is much more serious than the dam break.
China did not have a tailings pond before liberation. Since 1953, the Yangjiazhangzi Mining Bureau of Liaoning Province has built China's first tailings pond. So far, thousands of tailings ponds have been built nationwide, which basically meets the needs of the mine. However, due to various reasons, the safety status of the tailings pond is not optimistic. In general, about one-third of the quarantine warehouses have hidden dangers in different degrees, and severe dam failures have occurred. Such as: September 26, 1962 Yunnan Tin companies are fire valley tailings dam, the death of 171 people and injuring nine people; August 25, 1985 Hunan Nonferrous Shizhuyuan mine tailings dam ridge horns, death 49; April 30, 1986 Anhui Huangmei iron ore Jinshan Hill tailings dam burst, the death of 19 people and injuring 95 people; May 24, 1992, Luan River County, Henan terracotta Township molybdenum mine tailings occur Large-scale collapse and death of 12 people; in 1993, a large-scale landslide occurred in the Panluo iron ore reservoir area of ​​Fujian Province, causing 14 deaths and 4 serious injuries; July 13, 1994, Dayeshan Copper, Daye Nonferrous Metals Company, Hubei Province The mine tailings pond collapsed, 28 people died and 3 people were missing.
At 10 o'clock on the morning of October 18, 2000, the tailings reservoir of Hongtu Concentrator, located in Acid Water Bay, Dachang Town, Nandan County, suddenly collapsed, causing the collapse of some houses and some houses in the residential area of ​​Tongkeng Mine in the downstream Huaxi Group. . According to investigations by relevant departments, the accident caused a total of 28 deaths. When the collapse occurred, the loose waste ore rushed down and smashed for hundreds of meters. The sewage and mudslides rushed more than 2 meters high, and hundreds of houses near the sand dam were destroyed in an instant. The three dormitory buildings of Liuzhou Huaxi Group Co., Ltd. were also overwhelmed, and people who could not escape were instantly devastated. The "debris flow" formed after the collapse of the sand dam stretched more than 600 meters. The huge black stream actually ruined the tractors, motorcycles and road pedestrians that were heading for the first time...
Each accident in the tailings pond not only causes casualties, but also causes huge economic losses and has a very bad impact on society.
The destruction accidents of foreign tailings ponds have also been reported. The research of the Pollution Assessment Team of Clark University in the United States shows that the damage of tailings reservoir accidents ranks 18th among the 93 accidents and public hazards in the world. It is second only to nuclear explosions, nerve gas, nuclear radiation and other disasters, and is more serious than other 60 kinds of disasters such as aviation crashes and fires. The tailings reservoir accident that directly caused more than 100 deaths is not new.
In July 1985, the Puripil tailings mine in Italy collapsed and 250 people were killed. In 1965, a copper mine in Chile was destroyed by an earthquake and killed 210 people. A copper mine in Zambia in Africa and a platinum mine in South Africa damped in 1970 and 1974, killing 100 people. The US Buffaloni River tailings dam broke the dam on February 26, 1972, killing 125 people and leaving 4,000 people homeless.
Safety supervision of tailings pond
All countries in the world attach great importance to the safety of tailings ponds. The United States, Canada and other countries have listed the safety of tailings ponds as an important part of the safety inspection of the country's labor departments. In the United States, the Technical Center of the Mine Safety and Health Administration of the Ministry of Labor has developed guidelines for the safety inspection of tailings ponds. The safety inspection headquarters and inspection stations of the six districts under the Mine Safety and Health Administration must inspect the tailings pond twice a year, and timely issue notices of the hidden safety hazards for a limited time. Those who fail to deal with it in time and have no sufficient reason to explain the reasons are subject to severe economic punishment or even prosecution. Countries such as Canada have stipulated that the design and acceptance of tailings ponds must be reviewed by the labor department.
The International Dam Committee established the International Dam Committee Mine and Industrial Tailings Dam Branch in 1984. This branch has been independently established. It has developed a series of safety guidelines for the world's growing tailings ponds and exchanged countries' tailings ponds. The legal data and technical experience of safe work promote the development of safety technology for tailings ponds.
After the founding of New China, under the attention and care of the party and the state, the professional team of tailings pond engineering has grown from scratch, and now has all kinds of talents in tailings engineering research, survey, design, construction and production management, and the professional is complete. High level and excellent quality. Theoretical research on tailings concentration and transport and application of new high-efficiency equipment, theoretical research and production practice of seepage and stability analysis of high stack dams, theory and practice of reducing dam body saturation line to increase dam stability, karst area and seismic area Tailings reservoir construction, tailings water treatment, tailings dam observation system, mid-line method and downstream method dam construction research and practice, fine mud dam theory and practice, comprehensive utilization of drainage system, reclamation and tailings Achieved a very high level.
In order to strengthen the management of tailings ponds, China has placed special emphasis on the safety supervision of tailings facilities in the form of legislation. In the "Mineral Safety Law of the People's Republic of China", it is stipulated that mining enterprises should take preventive measures against the hazards that may occur in the tailings pond. It is also clear that the competent labor administrative department of the State Council implements unified supervision over the national mine safety work. The labor administrative department of the people's government at or above the county level shall exercise unified supervision over the mine safety work within its administrative area.
With the reform of state institutions, the safety production supervision and management departments of the state and local governments are currently exercising their powers of supervision and management of production safety. The safety supervision of the state safety production supervision and administration department for the main body is on behalf of the state supervision. This unified supervision with legal form has the following basic characteristics:
1. Authoritative: Reflecting the will of the state, it is not in the supervision of other kinds and the duties of other departments.
2. Mandatory: Backed by national coercive power.
3. Universal binding: the supervision of the labor department is generally binding on the mining of mineral resources within the jurisdiction of China.
Main regulations of library safety supervision and management
1. Basic regulations
As an important production facility and environmental protection facility of the mine, the tailings pond is also an important source of danger. Its construction and management must comply with:
Mine Safety Law of the People's Republic of China
Implementation Regulations of the Mine Safety Law of the People's Republic of China
2. Main regulations and standards for engineering construction
(1) Design Specification for Tailings Facilities of Mineral Processing Plant (ZBJ1-90)
(2) "Safety Design Regulations for Tailings Reservoir of Uranium Smelting Plant" (EJ794-93)
(3) "Procedures for the Construction and Acceptance of Tailings Facilities" (YS5418-95)
(4) Technical Specifications for Construction of Rolled Earth and Rock Dam (SDJ213-83)
(5) Regulations for Engineering Geological Survey of Upstream Method Tailings Dam (YBT11-86)
(6) "Safety Regulations for Closure of Tailings Reservoir"
3. Main regulations and standards for production management
(1) Regulations for the Management of Metallurgical Mine Tailings Facilities (90) Metallurgical Word No. 185
(2) "Safety Management Regulations for Tailings Reservoir" (Order No. 20 of the State Economic and Trade Commission)
(3) "Regulations on the Qualification Assessment of Special Operational Operations for Mines" (Ministry of Labor, 1996, No. 35)
(4) Interim Measures for the Examination and Management of Qualifications of Tailings Reservoir Safety Technical Service Organizations
4. Main regulations and standards for safety supervision
(1) "Safety Management Regulations for Tailings Reservoir" (Order No. 20 of the State Economic and Trade Commission)
(2) Notice on the Safety Acceptance of Closed Reservoirs of Tailings Reservoir (National Economic and Trade Commission)
(3) Local regulations
I don’t know how to automate
When talking about the Wangershan Mine Reservoir without the approval of the relevant departments, the construction team was working automatically, Professor Tian said seriously that this is absolutely impossible. Article 19 of the Regulations on the Safety Management of Tailings Reservoir stipulates that the re-enablement or conversion of the tailings pond after the closure of the warehouse must be verified by feasibility design and reported to the safety production supervision and management department for examination and approval.
For example, he said that on May 7, 1994, the tailings reservoir of the Yongfu tin mine in Yunnan was dug under the tailings dam due to violation of safety regulations, causing a large area of ​​collapse and 13 people died.
Then he rolled a piece of paper on the table, a schematic diagram of tailings with lead-stroke out. (slightly)
1. Initial dam; 2. Stacked dam; 3. Drainage pipe; 4. First drainage well; 5. Subsequent drainage well; 6. Tailing deposit
Just as a reservoir is used to store water, a tailings pond is used to store tailings. However, unlike dams, tailings dams usually have good water permeability to remove water from the reservoir. The tailings dam consists of an initial dam and a stacking dam. The initial dam is generally piled up by masonry, and the accumulation dam is deposited with deposited coarse tailings as the tailings increase. The structure of the dam body contains a large area of ​​thick layer of fine mud sandwich, which makes the dam body unstable. In the event of a flood disaster or man-made damage, a circular arc-shaped sliding surface will cause a dam break (shown below). (slightly)
The tailings pond of the gold mine has its own particularity. First, the choice of the tailings pond dam site often tends to occupy less farmland. Most of the terrain conditions are poor. The valley is narrow, the slope is steep, the reservoir capacity is small, and the catchment area is large. Hongkurong is small, resulting in a relatively high dam. In the arid areas, such as the concentrating plant has the requirement of returning water, the water level in the dam is high for a long time, forming a high-energy “debris flow†artificially built. Second, due to the characteristics of the beneficiation process, gold mines use gold flotation, cyanidation or flotation and cyanidation to extract gold. In recent years, in order to improve the recovery rate of gold, the grinding fineness has been increased, -200 mesh. The tailings have a particle size of 70% to 95%, which brings certain difficulties to the tailings dam construction. It is usually easy to cause the immersion line of the dam body to be high, and the seepage of the dam slope, the piping and the swamp of the dam foot, and the dam body is stable. Sexuality brings disadvantages.
In order to prevent serious damage caused by the over-excavation of tailings ponds, Article 14 of the Regulations on the Safety Management of Tailings Reservoirs promulgated in Order No. 20 of the State Economic and Trade Commission stipulates that no unit or individual may be in the library without technical argumentation and approval. The area is engaged in mining operations. It is strictly forbidden to blast the reservoir area, over-excavate tailings and fish frying and other activities that endanger the safety of the tailings pond.
At present, the development and utilization of the tailings pond that has been closed must be approved by the environmental protection departments at the local and municipal levels and the safety production supervision departments at the local, municipal and provincial levels.
Development and utilization of tailings pond
In our vast territory, there are a large number of abandoned tailings ponds, dumping sites, exposed pits and barren hills damaged by mining. It is estimated that there are about 60 million mu of abandoned land in various types of industrial and mining in China. This is a large land and a large resource! How can these resources be used effectively?
This is a worldwide problem. The use of tailings ponds involves many disciplines such as geology and resources, mining engineering, environmental protection, landscape aesthetics, biological ecology, and metal toxicity toxicology. Since the average particle size of the tailings is only 0.07 mm, the mechanical index is very poor and it is difficult to use it on earthworks for a large scale. In some places in the country, bricks are made of tailings, but only a small amount is used. At present, the main focus is on land reclamation, and there are already good examples in China.
In the five-kilometer tailings reservoir owned by Anhui Tongling Nonferrous Metals Co., Ltd., a demonstration site for landless reclamation has been completed. The tail sand beach, which was once dusty and flying, has been covered by green grass today, and green trees have become a scene along the Yangtze River green belt.
In the pilot project of the reclamation of the tailings pond of Gushan Mining and Concentrator of Yunnan Tin Industry Group Co., Ltd., 225 mu of bamboo forest has been built. In the next three years, Yunxi will rehabilitate 9375 acres of land. At present, about 1,590 mu of land use has been completed. After 3 years, the company will increase the net cultivated land by 6,900 mu and the forest land by 1515 mu, and develop 4,845 mu of sweet bamboo shoots and flowers, economic fruit forests and high ecological economic parks.
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