All coal mining countries in the world will give priority to the development of open-pit mining as the main way to increase coal output. As long as conditions permit, centralized mining will be realized as far as possible to improve labor productivity and reduce costs. The same is true in China. Fushun West open pit mine and Haizhou Open Pit Mine expanded and constructed in the early days of the founding of the people's Republic of China, Pingzhuang, Yima, Hami and other open pit mines constructed in the 1960s, and Yimin, Huolinhe, Zhungeer, Antaibao and other large-scale open pit mines constructed in the 1980s have made great contributions to the growth of coal output and the construction of national economy in China, and have also achieved great economic benefits.

However, based on historical reasons, the limitation of understanding nature and the imperfection of laws and regulations, the rapid development of open-pit coal mining has also brought a series of mine environmental problems and ecological damage, which have seriously affected the ecological environment quality and sustainable economic development of the region. This is a major problem that we need to solve urgently and take seriously.　　

(1) environmental problems caused by open pit coal mining

The pit formed by open-pit coal mining induces a series of geological disasters such as landslide, collapse, water and soil loss and debris flow due to geological structure, slope rock mass, surface water and groundwater, and also causes ground deformation and endangers the safety of industrial enterprises and residential buildings in the surrounding areas. It not only caused huge economic losses but also destroyed the original ecological geological environment.

(2) causes of environmental problems caused by open-pit coal mining

The environmental problems of open-pit coal mining in China are complex, diverse, special and sensitive. Due to the influence of specific historical factors, the geological environment and ecological environment of mining cities are greatly affected and destroyed. With the enhancement of national environmental protection awareness, the environmental conditions of new mining areas built since the 1980s have improved, and some mining areas have reached a better level. For example, the Antaibao open pit mine in Pingshuo has solved the problems of environmental recovery and treatment in open pit mining. Therefore, it is of great significance to sum up the experience and lessons in this respect, and it is very necessary to do a good job in the prevention and control of environmental problems in open-pit coal mining.

In the period of planned economy, the profits of coal mining enterprises were all turned over to the state, and few funds were invested in the treatment of environmental problems caused by mining.

For example, large state-owned mining enterprises such as Fushun West open pit mine and Fuxin Haizhou Open pit mine have basically turned over their coal, profits and benefits to the state, while the serious environmental hazards caused by mining in the past few decades have been left to the local authorities; The scope and intensity of environmental hazards in the early and middle stage of open-pit coal mining are small, which has not attracted the attention of decision makers, managers and miners. In addition, the weak awareness of environmental protection has caused more and more environmental hazards, which has led to the deterioration of the environment and the occurrence of disasters decades later.

What cannot be avoided is that these environmental problems precipitated by history can be managed and restored gradually only by relying on the government at all levels to increase investment or actively organize.

In the past, the traditional geology, mining and management disciplines did not or rarely integrate the exploration, evaluation, prediction, management, legislation and law enforcement of mine environment with the exploration of open-pit coal mines, the construction, design, production and pit closure of open-pit coal mines. Each discipline has its own emphasis. For example, open-pit mining pursues the least stripping and the most coal mining. As long as there is no landslide, the steeper the slope, the better. It rarely considers the ground deformation or the disaster after the pit is closed, and rarely takes the comprehensive long-term economic benefits, social benefits and environmental benefits as the starting point of this discipline.

The environmental problems of open-pit coal mining are fundamentally caused by the change or deterioration of the environment caused by human mining engineering activities. This requires policy makers, managers and producers to have strategic vision and strategic mind. They should not only pay attention to their own and recent economic benefits and prosperity, but also engage in open-pit coal mining from the height of maintaining sustainable social and economic development and caring for the homes of human beings. They should actively and actively use mining projects to improve and beautify the surrounding environment, turn harm into harm, and turn disadvantage into advantage, To achieve coordinated development of resource development and environmental protection. Antaibao open-pit coal mine has made great achievements in preventing water and soil loss, changing soil composition, realizing waste land vegetation, greening, reclamation and biological treatment, making the ecological environment of the mining area better than before mining. The experience in this respect is worth studying and popularizing.

(3) countermeasures for the environmental problems of opencast coal mining

The prevention and control of various environmental problems and disasters caused by open-pit coal mining is a complex, comprehensive and huge system engineering. We should apply the principles and ideas of environmental geology, mining, systems engineering, engineering economics and other disciplines to study prevention and control measures. From paying attention to analytical thinking to analytical, coordinated and comprehensive thinking; From the development of single technology and division of disciplines, conventional observation has been transformed into the development of composite technology, modern information means and multi-disciplinary comprehensive system. Pursue the best economic, social and environmental benefits. Realize the coordinated development of coal mining and environmental protection, and realize the sustainable development of social economy. This paper puts forward some opinions on the treatment of environmental problems caused by open-pit coal mining.

(1) Distinguish between old and new accounts of environmental problems, so as to clarify the main body and responsible person of environmental recovery and governance.

It is obviously unrealistic for the current mining enterprises to undertake the management of environmental problems left over by history. Therefore, it is an important premise to distinguish the old accounts and the new accounts as soon as possible to clarify the responsibilities, contents, sources of funds and implementation subjects of environmental restoration governance.

It is suggested that the division of old and new accounts should be based on the year when the enterprise changes from planned economy to market economy, that is, the profit of the enterprise is basically turned over to the state and the enterprise is responsible for its own profits and losses.

The old debts should be mainly borne by the government, mainly relying on the investment, organization and governance of the state, provincial and municipal governments. The new accounts must be mainly borne by the enterprise, and the principle of "Whoever destroys shall be responsible for governance" shall be strictly implemented.

For old mines such as Fushun West open pit mine and Haizhou Open pit mine, the environmental problems caused by historical reasons are mainly treated and restored by the state and the government; After entering the market economy, the new environmental problems caused by open-pit mining must be borne by the enterprises, and the enterprises shall be responsible for the treatment and recovery of the production costs; For newly-built mines, it is necessary to define the responsible person in terms of legal system and management from the beginning of survey, project approval, construction, design and production, and to be responsible for the closure of the mine. Ensure that the environment is restored and improved.

(2) Improve and revise the formulation of relevant standards and specifications, including open-pit coal mining, so that the environmental management and governance of mining can be operable and standardized, and the environmental management and governance of mining can be operable, targeted and scientific. There are laws to follow to realize the management and supervision of the whole process of open-pit coal mining from exploration, construction, production and pit closure. To realize a virtuous cycle of change destruction recovery reconstruction of open-pit coal mining environment. Promote sustainable development. This avoids and reduces the harm of environmental problems and the occurrence of geological disasters from the source.

(3) The planning of construction and mining of open-pit coal mines shall fully consider the environmental problems and disasters that may be brought by mining to the final boundary. In the planning and design, it shall be fully considered not to design civil and industrial buildings in the possible environmental disaster area. This is necessary for the construction of new opencast coal mines.

(4) In open-pit mines with serious geological environment problems, environmental geological monitoring websites and geological disaster early warning systems shall be established. It is mainly established for the open-pit coal mines that have been built and are in production, and the environmental disaster problem has already existed and has affected and endangered the safety of ground buildings and people's lives and property. For example, Fushun Power Plant and Xingping Road on the ground are equipped with ground deformation monitoring network to monitor and predict the deformation trend in real time, so as to provide a basis for taking disaster prevention measures in time and avoiding losses.

(5) The old open-pit coal mine has been exploited for several decades, and the environmental geological disasters caused by it have become a fact. It is suggested to follow two principles for the prevention and control countermeasures: first, the principle of avoiding and giving way. The project construction and residential buildings should not be arranged in the disaster area, and the existing ones should be considered to be relocated as much as possible; The second is the principle of targeted governance. For the important settings and buildings that are not suitable for relocation, the principle of targeted governance shall be adopted. For the important settings and buildings that are not suitable for relocation, targeted governance shall be adopted, such as reinforcement, shielding, mining backfilling, slope toe pressing, etc. The technical and economic comparison of several schemes should be carried out, and the technical feasibility, economic rationality and safety risk should be comprehensively considered.

(6) For the new open-pit coal mine, the decision-makers, managers and miners should stand on the strategic height of protecting the ecological environment and actively improve and rebuild the surrounding environment through mining engineering activities. For example, the Antaibao open pit coal mine in Pingshuo has made gratifying achievements. By opening open-pit mines, building reservoirs, changing river courses, changing terrain and strata, adjusting soil structure, preventing water and soil loss, and reclaiming and planting, not only environmental deterioration was avoided, but also a new mining area with better ecological environment was built through open-pit coal mining.