Slope stability and safety, environmental control and ecological reconstruction of closed pit open pit mine with combined open pit and underground mining

There are generally two situations in which open-pit workers jointly exploit open-pit coal mines: one is the closed-pit stope pit left over from history, which has caused a series of environmental geological disasters and will continue. The combination of open-pit mining and underground mining leads to a series of environmental geological disasters such as surface deformation, underground mining subsidence and slope landslide in and around the mine. It is extremely difficult to control and rebuild the slope stability and closed pit environment. The other is the method of backfilling open pit with internal dumping soil, which is widely used in newly built large open pit coal mines in China. This method not only fundamentally eliminates the occurrence of surface deformation, ground subsidence and slope landslide, but also is beneficial to the governance and reconstruction of ecological environment. Therefore, it should be strongly suggested and raised to the level of legislation and norms, and it is required to realize pit backfilling, land reclamation, environmental control and ecological reconstruction, that is, to realize the integration of open-pit production, environmental control and ecological reconstruction through joint mining of open-pit workers.

8.2.4. 1 Slope stability and environmental improvement of closed pit and reserved pit in open pit.

Take Fushun West Open-pit Mine as an example.

(1) Experiences and lessons of closed pit environmental problems in Fushun West Open-pit Mine under the influence of combined open-pit mining.

The environmental problem of closed pit in Fushun West Open-pit Mine is actually a typical closed pit problem under the influence of combined open-pit mining. The environmental geological disasters caused by it are complex, special, diverse and sensitive, which have great influence and destruction on the urban geological environment and ecological environment. The problems and harms of sedimentation are unprecedented and typical in the old mining cities of China.

1) Historical problems are the main sources of many environmental problems, great harm and difficult control in closed pit open pit mines.

The environmental problems of closed pit under the influence of combined open-pit mining in Fushun West Open-pit Mine are mainly caused by historical problems. It includes two parts: one is before liberation and the other is after liberation.

Predatory mining and disorderly factory construction before liberation have laid an irreversible hidden danger for today's environmental problems.

Fushun coal mine was officially mined in Guangxu 190 1 year, 1903 was taken over by Russia, 1905 was at war with Russia, and was occupied by Japan to 1945,1946 ~/kloc-0.

Predatory and crazy mining before liberation did not consider the future environment, layout and planning. Fushun West Open-pit Mine was built in 19 14, Shengli Mine in 1907, Fushun Power Plant in 1908 and Fushun No.1 Petroleum Plant in 1928. Both projects are built near the open pit mine, with the upper open pit mining and the lower underground mining, and the surface is located in the belt of F 1A fault. The open-pit combined mining mode in mining area "lays the groundwork" for environmental problems.

After liberation, enterprises such as open pit mine, No.1 oil plant and power plant were owned by the state, pursuing output, output value and profit. Great contributions have been made to the country and people, but the lack of awareness of the need to protect and control the mine environment and the lack of scientific long-term planning and strategic vision have made the mine environmental problems worse and worse decades later. Indeed, we have won the victory over nature. In the 50 years since the founding of New China, Fushun Mining Area has produced more than 450 million tons of high-quality coal for the country, with a profit and tax of 4.6 billion yuan. Open-pit mining accounts for about 1/3 (from 1997, 252 million tons of open-pit mining and 47/kloc-0 million tons of oil shale). However, nature began to retaliate against us. Landslides began to occur in open-pit mines, and the slopes of mines were unstable in the 1980s, resulting in frequent disasters. The foundation of Fushun No.1 Petroleum Plant has been deformed. Since 1987, the deformation has increased sharply, which has endangered the safe production of important devices in the plant (such as underground tunnels and Xiqi cracking devices). Fushun power plant is also affected by underground and open-pit coal mining, and the surface movement occurs in the F 1A fault zone, which affects the safety and production of the device. Residents and buildings on the eastern north side of the open pit mine also began to be injured or destroyed. At this time, it has attracted great attention from countries, provinces, cities, factories and mines. In order to "double insurance", we have to spend huge financial, material and human resources on exploration, evaluation and management. With the closure of the open pit mine, the task of managing the mine environment will be more arduous, and it still needs the efforts of several generations.

2) The traditional geology, mining and management disciplines do not organically combine the exploration, evaluation, prediction, management legislation and law enforcement of mine environment with the construction, design and production of open-pit mines, and lack the practice and theory of joint mining safety control, environmental management and ecological reconstruction of open-pit mines.

In geological survey, geological prospecting units only find out the coal reserves and grade, make a preliminary evaluation of the industrial prospect of the deposit, make no or little evaluation of the environmental impact, and put forward no or little countermeasures for the negative impact; The mining engineering discipline of Mine Production Technology Department only designs and produces from all technical links of coal mining, and only pays attention to mining more minerals, without or with little consideration of the impact on the surrounding environment, and how to restore the geological environment and ecological environment during and after mining, not to mention the environmental geological disasters and prevention measures that may be caused by the decline of the strength, stability and safety of slope rock mass after closed pit mining and gradual water filling, not to mention the environmental impact of joint open-pit mining. The management department pays attention to the immediate economic benefits, fails to foresee the possible harm in a few years, and often ignores the long-term social and environmental benefits, thus ignoring the long-term economic benefits, or lacks scientific and specific operating rules and standards, or fails to abide by the law, lax enforcement, and fails to investigate the law, resulting in a situation that it seems that someone is in charge, everyone is in charge, but no one is in charge.

With the central government and governments at all levels attaching great importance to the work of resources and environment, a series of policies and regulations have been formulated to strengthen the management and governance of mine environment, strengthen the prevention and control of geological disasters, and realize the coordinated development of resource development and environmental protection. We realize that it is necessary to deeply study the relationship between human survival activities such as exploration, mining, management, benefit and law enforcement in the traditional theory and the geological environment, so as to bring order out of chaos in theory.

In terms of discipline and technology, it is necessary to organically combine open-pit coal mining, geological disaster prevention and ecological geological environment restoration, and unify the investment in future governance with the benefits of mining to consider planning, design and production. Use modern technical means to prevent, mitigate and improve the geological environment changes caused by mining, and rectify the harm caused by mining to the environment. We must never exploit coal resources at the expense of irreversible destruction of geological environment and ecological environment. Only in this way can we achieve sustainable economic development, strengthen the country and enrich the people, and secure the world.

3) The environmental problem of closed pit in open pit mines is fundamentally that human mining engineering activities gradually worsen the environment, and various disaster-causing factors have long-term effects and complex superposition, which gradually lead to the occurrence and aggravation of environmental geological disasters. This requires decision-makers, managers and producers to have a strategic vision and mind, attach great importance to forecasting the possible changing trends and disasters in the engineering geological and hydrogeological environment of open-pit mines in the future, especially open-pit joint mining, carry out scientific research in this field, and implement comprehensive prevention and control.

(2) The general idea of pit closure in Fushun West Open-pit Mine under the influence of combined open-pit mining.

After the open pit mine enters the pit closure period, environmental geological disasters (including landslide, surface deformation, collapse, water pollution, spontaneous combustion of oil shale, dust, etc. ) Monitoring, prediction, prevention and utilization are carried out in stages through the mode of gradual transition from dry pit (drained slope) to wet pit (slope that will be filled with water without drainage).

According to engineering geology, deformation dynamics and disaster risk, environmental geological disasters of open pit mine closure will be divided into two areas. Under the long-term monitoring of using the original monitoring line and expanding the environmental monitoring network, the modern technology and the established environmental geological information and early warning system are used to track and predict according to the regional dynamics. In particular, the deformation failure zone, deformation danger zone and general deformation zone of dumping zone, settlement zone and potential settlement sliding zone are predicted; Or the dynamic change trend of the boundary between disaster risk area and prone area during the transition from dry pit to wet pit, and study the corresponding preventive countermeasures and measures. For the change of hydrogeological environment (including water pollution, water quality evaluation and treatment, and water resources utilization) during the pit closure period, the original corresponding drainage system facilities (surface water drainage system, shallow water drainage system above the pit, and drainage system below the pit) have also changed from a single drainage and drainage function to a multi-function integrating water collection, water quality evaluation, water pollution control, lake diversion, landscape construction and water resources utilization. Considering the scheme that part of the stripped rocks enter the dump of the west open pit mine after re-mining in the east open pit mine, the disaster prevention, greening and reclamation design of the north slope of the open pit mine are carried out. For the remaining working area (mainly at the level of E2500-E2800, -90-248 in the southeast; E 1400-E 1500 area of the east building, E2600-E3600 and-150 level of the security coal wall on the southeast side) and the combined section at the end of the open pit mine should be exploited and protected in accordance with the current mine environmental protection regulations such as the Regulations on the Prevention and Control of Geological Disasters, so as to avoid new environmental geological disasters. At the same time, the disaster prediction, evaluation, remediation and reclamation of the three dumping sites were carried out to restore the ecological environment. The western garbage dump immediately started to work, followed by the Wang Liang garbage dump and the eastern garbage dump. In this way, a collection of various cultural landscapes, industrial landscapes, diversified management and sustainable development will be gradually formed to form a green garden in the south of Fushun. And summarize the experience and lessons of mine geological environment management, regulations and governance, and become a demonstration of environmental management, governance and restoration of open-pit mines in China.

(3) Several schemes of closed pit utilization in Fushun West Open-pit Mine under the influence of combined open-pit mining.

The utilization of open pit mine after pit closure should be based on the monitoring, prediction and prevention of geological disasters before and after pit closure, and comprehensive research should be carried out to obtain the best environmental, social and economic benefits. In other words, in the process of gradual transition from dry pit to wet pit, the best utilization scheme should be studied.

① Transition from dry pit to wet pit, and finally fill the lake. This scheme should be the most economical scheme on the premise that there are no important industrial facilities and residential buildings around or there will be no threat after filling the lake. The utilization of water resources can be realized by replenishing water to lakes, restoring ecological environment and building landscapes.

(2) Mine backfill or local backfill utilization. Cutting hills and leveling pits (including stripping and backfilling) is the most effective method to prevent environmental geological disasters and close pits for reclamation. However, from the economic point of view, it is difficult to realize the project of filling or partially filling the pit with 654.38+0.7 billion m3 without endangering the ground and buildings, which is not only a huge investment, but also a long time. However, the resumption of mining in the East Open-pit Mine and the discharge of some stripped materials into the mine pit are conducive to reducing surface deformation and disasters.

③ Dry pit utilization scheme. Theoretical excavation value of open pit mine 1 trillion yuan. Whether we can make use of this advantage, combine the long-term planning of the country to build giant buildings, or comprehensively plan and build the most distinctive human landscape in the world from the bottom up is also a learning plan. But if there is no huge capital injection at home and abroad, or strategic demand, I am afraid it is difficult to make a difference.

(4) The lower part is impounded to form a lake, and the upper part is drained for reclamation and greening. This is a compromise scheme that combines the above schemes. Planning and research are carried out from the aspects of water resources utilization, environmental restoration and environmental disaster prevention. But the benefit ratio of input and output should be considered comprehensively.

(4) Countermeasures of environmental geological disasters before and after the closure of Fushun West Open-pit Mine under the influence of open-pit mining.

Through the investigation, comprehensive analysis, catastrophe prediction and evaluation of environmental geological problems before and after the pit closure of Fushun West Open-pit Mine, and the research on the present situation, causes, characteristics, hazards and development trends of various environmental geological disasters induced and accumulated by open-pit mining for more than 80 years, it is clearly shown that the prevention and control of environmental geological disasters in open-pit mines is a comprehensive, complex and huge system engineering. We should use the principles and ideas of environmental geology, systems engineering, engineering economics and other disciplines to study prevention and control strategies. Minimize the impact of environmental disasters caused by the closure of open-pit mines, explore prevention methods suitable for rational development and utilization, and realize sustainable development.

1) Establish the environmental geological monitoring website of open pit combined with open pit mining. The principle of building a station is to make full use of the original urban monitoring website and combine the characteristics of the closed pit system to build a station. The monitoring network consists of three parts. First, on the basis of perfecting the monitoring points of surface deformation and underground displacement left by the original enterprises, including the first oil plant, power plant and open pit mine, a long-term monitoring network of surface deformation and underground displacement in the surrounding environment of open pit mine is established to realize long-term monitoring of surface displacement and underground displacement, and accumulate data and information for deformation characteristics analysis, deformation development trend and catastrophe prediction, and provide prevention basis. Surface deformation monitoring is the main method, and underground displacement is established according to the needs of different regions. The second is hydrogeological environment monitoring. Fully rely on the basic data and monitoring methods of groundwater dynamics, groundwater environment and geological disasters accumulated by provincial and municipal geological environment monitoring stations for a long time, expand monitoring, and incorporate the monitoring of closed pit environment into the business of municipal geological environment monitoring stations. The third is the monitoring of air, water, soil, rocks, waste gangue and environmental pollution. Fully rely on and make use of the data, monitoring means, instruments and equipment of the municipal environmental monitoring station established by the environmental protection department system. Expand the monitoring content and scope, and incorporate the monitoring content related to the closed pit environment into the business of environmental monitoring stations. The monitoring summary of the three parts can realize comprehensive and long-term tracking monitoring of the closed pit environment of open pit mine. The surface deformation monitoring network mainly needs to establish three additional monitoring lines (line D, line E and line F) to the east of E 1500 and nine monitoring points to the south of Qiantai Mountain, so as to realize the monitoring of potential settlement slip zone and deformation monitoring in Qiantai Mountain area. The above three parts of monitoring are connected into a network to form a system, collect data and share information.

2) Based on the open-pit mine geological environment information system and the open-pit mine environmental geological monitoring network, the open-pit mine geological environment disaster early warning system is established. This early warning system basically includes five aspects: investigation and evaluation of environmental geological information change trend, long-term and continuous monitoring network, tracking monitoring data, disaster development trend analysis, disaster early warning information dissemination, consultation and prevention countermeasures and suggestions. We can rely on and make full use of the geological environment and geological disaster monitoring system established by regional (such as city) geological environment monitoring stations and the early warning system established by the early warning and forecasting monitoring network, which are interdependent and can also be managed as a subsystem of the municipal geological disaster early warning system. The main purpose of the system is to track and predict the trend of environmental changes and disasters with the gradual closure of open pit mines, and to serve the management, monitoring and disaster prevention of mine closure. Emphasize spatial early warning, that is, work based on main control factors (such as stratum lithology, geological structure, closed pit landform, stratum mutation, groundwater, etc.). ) and induced factors (such as rainfall, ablation, man-made engineering activities, mine earthquakes, etc. ) closed pit environmental geological disasters. According to the long-term monitoring and analysis, the areas or places where environmental geological disasters will occur in a certain period of time, the dynamic change trend of the boundaries of dumping slip zone, settlement slip zone and deformation zone in engineering geology and deformation zoning, the development trend of potential areas, the early warning and forecasting model of environmental geological disasters, and the corresponding prevention and control countermeasures and suggestions are defined.

The environmental monitoring network system and early warning system of open pit mine closure should be built and put into operation in the early stage of open pit mine closure, that is, in recent years. First, realize real-time monitoring, prediction and management of geological environment in the early stage of pit closure; The other is to accumulate experience and information from engineering technology, policies and regulations, standard formulation, management and law enforcement through the whole process of pit closure; The third is to provide a basis for closing the pit (the mining process before the final mining), preventing and restoring the geological ecological environment, reducing the environmental geological disasters after the pit is closed, reducing its harm and control difficulty, and economically reducing investment.

3) Countermeasures for prevention and control of environmental geological disasters and surface deformation in the same side area before and after pit closure of open pit mine. The environmental geological disasters in the surrounding areas before and after the open pit mine is closed are mainly ground deformation, subsidence, ground collapse and landslide. The focus is on the North Gang, and the disasters caused by it have a great impact on the First Oil Plant, power plant and residential buildings, and the damage is also very serious. Prevention and control is also mainly aimed at this area. The above-mentioned monitoring network and early warning system are also mainly arranged in the north, providing basic information for formulating prevention and control countermeasures. Prevention and control measures are based on two points: first, the principle of avoidance. Do not arrange or arrange engineering construction and residential buildings in the dumping area, the dumping landslide area, the dangerous area of the collapsed landslide area or even the deformation area, and do not engage in new double insurance. In other words, the area south of the F 1A fault in these two areas should be avoided. The second is the principle of target governance. The existing important industrial settings and buildings located in the deformation zone that are not suitable for relocation should be dealt with in a targeted manner.

4) Countermeasures for prevention and control of hydrogeological environmental disasters before and after pit closure. Hydrogeology and environmental disasters are mainly in two aspects: first, during the transition from dry pit to wet pit, the strength of rock mass is reduced due to flooding, and landslides and collapses may occur; Second, under the condition of runoff, most of the industrial and domestic sewage from power plants, oil plants, cement plants and other enterprises on the ground and the surrounding residents are discharged into the alluvium, which will become the source of water recharge other than rainfall and river recharge, and the water quality will be seriously polluted. Harmful elements in the rock mass may also pollute the water body, which will become one of the biggest problems after the open pit mine is closed, and will affect the long-term ecological environment and the utilization and development of water resources.

In the open pit production, a complete drainage system has been established. The basic pattern is that the surface water is not into the pit, the upper part of the pit is shallowly drained, the lower part is stored in the open air, and Shengli Mine is discharged.

There are two intercepting ditches on the south ground: the north drainage ditch flows into Daguan culvert from Donggang to the west, and the south drainage ditch flows into Guchengzi River from sand injection well to the west. There are 50 kilometers long permanent and temporary ditches at all levels in the pit, which flow to the pumping station respectively.

Combined with this specific situation, the best and most economical prevention and control countermeasures are to make full use of the drainage system before the pit is closed, gradually transform it with the transition from dry pit to wet pit, and improve the system and setting of water quality evaluation, water pollution prevention and water resources utilization after the pit is closed. After surface water is collected by ditches, it is allowed to flow into the pit after water quality analysis and water pollution prevention. According to the needs of prevention and utilization, the bottom-up pumping station in the pit is transformed into corresponding devices. As the water fills the lake and the lake rises, it is gradually abolished or retained. The project mainly focuses on the utilization of water resources.

5) Prevention measures for landslide, collapse and other disasters in the pit after the pit is closed. In the later stage of open-pit mining, internal drainage was added, and the west dump was closed in 2000, and the number of internal drainage lines was increased from 4 to 16. The maximum capacity of internal discharge will reach 8.4 million m3 per year. This is very beneficial to stabilize the slope and reduce the ground deformation. Because of the west side of W200, the slope protection is realized on the north side of the west side. Local internal drainage below 14 section obviously reduces ground deformation, which is only 10% ~ 50% of the same period last year (line A and line C). However, with the open-pit mining and stripping project concentrated in the range of Ewo ~ E 1200 in the central region, the ground deformation in the east (line B) is still increasing. With the arrival of the end of the open pit mine, railway transportation will be changed to automobile transportation, and the rich and poor oil shale mines will be combined by automobiles, and the slope will gradually become steeper. Moreover, after the pit is closed, the dry pit transitions to the wet pit, and the strength of rock mass decreases. Therefore, in some sensitive sections, such as those where landslides often occur, landslides and other disasters may occur, which will affect slope remediation and reclamation. In order to prevent this kind of disaster after the pit is closed, the best preventive measure should be to fully consider the stability and safety of the steep water slope after the pit is closed before the pit is closed, that is, in the later stage of mining, so as to avoid this kind of disaster after the pit is closed. The East Open-pit Mine has been approved for mining, and some waste rocks (lean ore and green shale) are planned to be discharged into the inner dump west of pit E 1400 in the West Open-pit Mine, which will help to slow down the deformation of the north slope and the ground and reduce the occurrence of landslide geological disasters. However, it is necessary to coordinate and plan as a whole, and comprehensively consider abandoned production and mine disaster prevention and utilization to achieve the best results.

6) It is an important countermeasure to improve and strengthen mine environmental management and governance before and after pit closure. It is very necessary and effective to formulate a set of complete standards and norms for the investigation, evaluation, production period and acceptance method of geological environment in open pit mines, especially the joint mining of open pit miners, in order to improve the level of geological environment management, law enforcement and prevention of geological disasters in closed pit environment. In addition, it is necessary to supplement and revise the provisions and contents of practical measures related to closed pit mining, environmental restoration, governance and reclamation, such as Code for Design and Construction of Open Pit Engineering and Theory of Subject Textbooks.

7) Establish and improve the mine environment management system and system based on modern technology (including the closed pit environment of open-pit combined mining), strengthen the state's supervision and management means of mine environment, and use various means and measures such as law, administration, economy, science and technology, publicity and education to systematically plan, adjust, monitor and govern all kinds of mining activities from the whole process of exploration, design, construction, mining and final mining. So as to effectively prevent mine environmental damage and disasters, including open pit mine pit closure, realize a virtuous circle of mine geological environment change-damage-recovery, and promote sustainable development.

Reuse of closed pit open pit mine jointly mined by open pit workers in 8.2.4.2

(1) Study on Joint Mining of Open-pit Miners and Workers Technical Route of Reuse of Closed-pit Open-pit Mines

Every year, many new coal mines are put into production in China, and a large number of coal mines are finally mined and abandoned. Among them, many old mining areas left over from history, such as Fushun and Fuxin, were jointly mined by open pit workers. Coal mining will inevitably affect and destroy the eco-geological environment, including land subsidence, ground fissures, collapses, landslides, aquifer destruction, landscape destruction and so on. At the same time, coal mining produces a large amount of waste water and waste residue, forming a large number of waste hills and dump sites; The residual coal or coal gangue in abandoned coal mines, gangue hills and dump sites may spontaneously ignite, which will have a great impact and damage on the environment and cause damage to the atmosphere, ecology and land environment of human settlements. All these will seriously affect the sustainable development of economy and society in areas where coal mines are located (such as coal cities) and the stability and harmony of human settlements. Therefore, the research on the reuse of abandoned coal mines and the re-exploitation of surplus resources is an important part of the research on coal mine safety and green mining technology and strategy, and an important part of establishing the economic and social evaluation system of coal safety, high efficiency and green mining. At the same time, it is also a great contribution to the construction, development and upgrading of environmental protection, ecological reconstruction and urban beautification in coal mining areas.

The research on the reuse of closed open-pit coal mines by joint mining of open-pit coal mines should be carried out in stages:

Step 1: Know the situation. It is to investigate, inspect and find out the basic situation (including residual coal resources) of the closed pit coal mine, including ecological geological environment damage, coal mining subsidence, surface deformation, landslide, aquifer damage, spontaneous combustion and other disasters caused by the coal mine before and after the closed pit;

The second step: targeted governance. Targeted control of environmental damage and various environmental disasters caused by closed pit coal mines. Including environmental and disaster area division, evaluation, monitoring and early warning, targeted treatment (such as mining subsidence, landslide, spontaneous combustion, etc.). ) scheme design and implementation, and put forward the feasibility study of reuse.

Step 3: Plan and design the reuse scheme of closed pit coal mine. That is, on the basis of finding out the situation and targeted management, the reuse plan of closed pit coal mine is planned as a whole. This kind of planning is often based on the sustainable development and environmental protection planning of the whole mining area to formulate the utilization planning of each specific closed pit coal mine.

Step 4: Implement and maintain the reuse plan of the closed pit coal mine. The implementation of the reuse plan should also be carried out step by step, and at the same time, the remaining coal resources should be exploited as much as possible. On the one hand, it is beneficial to the utilization of residual coal, a non-renewable resource; On the other hand, after the residual coal is exhausted, new hidden dangers are eliminated for the utilization and environment of the closed pit coal mine. After the implementation of the utilization plan, we should strengthen maintenance and monitoring, optimize the ecological environment, give full play to the expected environmental, social and economic benefits, and realize the green effect of coal mining from beginning to end.

(2) Reuse the closed pit open pit coal mine in Fuxin mining area through joint mining of open pit workers and underground workers.

Fuxin is called baili coal sea. Fuxin coalfield is 130km long and 8 ~ 20 km wide, with a total area of 2000km2 and recoverable area of 18 1km2. The four mining areas are 44.5km long and 3 ~ 8 km wide, with a total area of 168.4km2 and a mining history of nearly one hundred years. There are nearly 240 large, medium and small waste hills formed by coal mining, covering an area of 2885hm2, with a total accumulation of12.1×108m3. Fuxin mining area has 20 relatively independent subsidence basins, 2 large open-pit coal mines and 4 small open-pit coal mines. Coal mining subsidence area 13, total subsidence area 10 138hm2, and total goaf area of 7369hm2. There are hundreds of spontaneous combustion points of residual coal in Xinqiu open-pit coal mine, which have been closed for a long time, making the waste pit a smoking fire pit all day long.

Coal mining also causes environmental disasters such as groundwater pollution, slope landslide and collapse. However, Fuxin's coal resources have been exhausted, making Fuxin the earliest city in China where coal resources have been exhausted. How to control the destroyed eco-geological environment? How to use abandoned mines and open pits? How to transform resource-exhausted briquette mining areas and coal cities? These have become the most typical problems in China, which are rare in the world. From 38+0 to 65438+February, 2006, Fuxin was listed as the first batch of pilot cities for economic transformation of resource-exhausted cities by the state. The research on eco-environmental management and utilization and economic transformation in coal mining areas of resource-exhausted cities began.

In recent ten years, through the treatment of urban environment, mining area environment and abandoned coal mines, the reclamation of waste hills has obviously improved the urban ecological environment, 50 thousand mu of mining area has been afforested, and artificial waste hills have become artificial oases; The polluted surface water system (river) and groundwater have been treated, and the water environment has been greatly improved. It was rated as "excellent city for water environment management". Haizhou open-pit coal mine, which was closed in 2005, was identified by the state as the first batch of national mine parks in China. Construction started in September 2006, and now it has officially opened.

Haizhou Open-pit Mine National Mine Park is positioned as a world industrial heritage tourism project. The mine park is divided into four parts. A mine park built by a huge mine with a length of 4km, a width of 2km and a depth of 350m can produce great visual shock and spiritual shock. Ecological restoration demonstration area, large-scale mining equipment exhibition area, mine park museum, geological relics, open-pit mining simulation field and other coal mining and geological landscapes. It has become an encyclopedia showing the history of modern industrial development in China, and a holiday paradise for tourists to deeply experience industrial production.

Figure 8-25 shows the present situation of Haizhou Open-pit National Mine Park.

Figure 8-25 Haizhou Open-air National Mine Park

Haizhou Open-pit Coal Mine National Park is a new industry composed of abandoned closed-pit open-pit coal mine resources, which is a theoretical innovation and a breakthrough in fact, and is the most typical representative of the reuse of abandoned open-pit coal mines in China.

(3) Research on the reuse of abandoned closed pit open pit coal mines.

Small and medium-sized open-pit coal mines account for the vast majority in China, but the future open-pit coal base construction plan will mainly develop large-scale open-pit coal mines, so the reuse of closed pits and dump sites in large and medium-sized open-pit coal mines is the focus of green mining technology research. At present, the closed open-pit coal mines are mainly large and medium-sized open-pit coal mines left over from history, which have great influence, great difficulty in governance and great utilization value. For example, Haizhou open-pit coal mine is the world-famous and most influential open-pit coal mine recently closed. In addition, Fushun West Open-pit Coal Mine has also entered the early stage of pit closure, and its governance and utilization have been highly valued by the state and the international community.

Judging from the utilization of closed pits in open-pit coal mines, including open-pit coal mines and combined well mining, there are mainly four ways:

1) mine park construction

It mainly shows the landscape of open-pit coal mining relics, reflects the historical connotation of mining development, has research value and educational function, and can be used for people to visit, appreciate and make scientific investigations. Mining, geological landscape, natural landscape and human landscape should be integrated in the construction, and environmental renewal, ecological restoration and mining culture reappearance should be adopted to realize the organic unity of ecological benefits, economic benefits and social benefits.

This method is suitable for large and medium-sized open-pit coal mines with a long mining history and rich mining, geological relics, natural landscape, mining culture and mining development. The typical representative is Haizhou Open-pit Mine National Mine Park.

2) As a dump near an open-pit coal mine.

There are many open-pit coal mines in a coalfield. Taking the pits of open-pit coal mines that are closed or entered the pit-closing period at the initial stage of mining as the dump near the production of stripping materials in open-pit coal mines can not only save the land occupied by the dump, but also backfill the waste pits with stripping materials, and help to control and slow down the slope landslide and surface deformation of the waste pits. At the same time, the backfill mining area and other areas will be treated, the ecological environment will be rebuilt, and vegetation will be planted, and the mine forest park with green mountains and green waters will be planned and built.

The typical representative is Fushun West Open-pit Mine, which has entered the pit closure period. As a stripped dump of the restored East Open-pit Mine, the western inner dump does not occupy land, which is beneficial to the stability of the north slope of the West Open-pit Mine and to reduce the influence of surface deformation on the ground buildings. At the same time, the ecological environment of the north slope will be treated and rebuilt. After the pit is closed, it is planned to build a scenic forest park with green mountains and green waters that integrates ecology, culture and industrial landscape.

3) mining-internal drainage reclamation integration

In the production of open-pit coal mines, mining projects are actively used to implement internal dumping, so as to backfill while mining. When the pit is closed after final mining, huge pits are basically not formed, and most pits are backfilled and reclaimed. This is the best form of green mining in open-pit coal mines, especially in open-pit combined mining.

4) Reclamation and ecological reconstruction of abandoned open pit mines and internal dumping sites.

For the dump formed by open-pit coal mining and the pits of small and medium-sized open-pit coal mines that are not backfilled, the abandoned pits and dump are used for greening, vegetation greening and ecological reconstruction by covering the soil, and are treated at the same time of production. This is especially true for garbage dumps. As soon as the dumping steps reached the border, they began to be repaired. Before the pit is closed, the dump has been forested, and the ecological environment has been restored and rebuilt, resulting in high ecological, environmental, social and economic benefits.

Most abandoned open-pit mines are utilized by planting vegetation on composite soil. The treatment and ecological reconstruction of dump refers to the restoration of soil and environment after the dump reaches the boundary. For example, the greening effect of Yimin open-pit mine dump has been restored to the original ecological grassland state. Dumps in Huolinhe coalfield and Shengli coalfield are also used for greening and reclamation.

The research on the reuse of closed pit open pit coal mines and the re-exploitation of residual coal resources in China, including the joint exploitation of open pit workers and workers, can be carried out around the above methods in combination with the specific conditions of coal mines. However, the most recommended and should be adopted is the resource scheme of closed pit open pit coal mine, which adopts the integrated technology of production, reclamation, environmental management and ecological reconstruction.