Study on ecological restoration status and treatment countermeasures of abandoned mines left over from history

2.5 Repair Techniques

Mining has caused serious damage to topography and landform, and there are subsidence areas, tailings ponds and waste discharge fields covering a large area, etc. As of 2018, a total of 1.2×l04 ground collapse disasters have occurred in abandoned mines in China, and the solid waste stock is 4.96×1010t, with high construction technical requirements. Compared with water pollution and air pollution, mine restoration has less attention, less research on related technologies, and the existing technologies are relatively simple, mainly in geological environment management, secondary disaster prevention and control, vegetation restoration and land reclamation. In the "National Soil Pollution Survey Announcement" published in 2014, 1,672 soil points in 70 mining areas accounted for 33.4% of the exceeded points, and the main pollutants were cadmium, arsenic, lead and polycyclic aromatic hydrocarbons. The soil pollution control technology was weak, the plant survival rate was low, and no integrated control system was formed. In recent years, some new technologies have achieved good results, but the cost is high and the application is limited. In 2013, the Technical Code for the Protection and Restoration of the Ecological Environment in Mines (Trial) issued the development of industry standards, which did not enforce and play its due role in guiding technical requirements for the protection and restoration of the ecological environment, including waste dumps, open-pit stopes, tailings ponds, special roads for mining areas, mining industrial sites, subsidence areas, gangue yards, polluted sites, etc. The regulations on pollution prevention and control involving air, water and soil are relatively simple, and there are no more detailed technical guidelines and norms for one aspect, and no new technical norms have been issued since then.

In accordance with the differences in the types and mining methods of mines under different natural conditions, the state formulates standardized and serialized restoration standards and treatment technical norms to improve operability, enforce implementation, raise the level of mine treatment, and reduce the number of mines that do not meet the treatment standards. Strengthen the basic theoretical research of mine ecological restoration, improve the level of scientific and technological support, and reduce the application cost. At present, ecological restoration technology is mainly based on physical restoration, chemical restoration, biological restoration and joint restoration. Single restoration technology often cannot meet the needs of mine ecological restoration, and joint restoration technology will be more and more applied to mine restoration. Under the premise of ensuring the treatment of geological environment and the elimination of heavy metals and other major pollution, the mine restoration can improve the survival rate of vegetation, achieve the reconstruction of biodiversity and the restoration of regional ecological functions.

Step 3: Advice

3.1 Coordination mechanism of mine comprehensive treatment work

There are many fields and departments involved in the mine restoration and treatment project, and the corresponding work has been carried out with the focus on the restoration project and certain progress has been made, but there are still problems such as the overlapping responsibilities of various departments and the inconsistency of rights and functions. Therefore, the local government should set up a comprehensive mine management office, identify the member units, formulate working rules such as cooperation, consultation and information sharing, and transmit responsibility pressure at various levels to ensure that the mine restoration and management work is carried out effectively and orderly.

3.2 Improving laws and regulations

There are relatively few laws and regulations related to mine ecological restoration. The Mineral Resources Law is mainly aimed at exploration and mining, and does not deal with mine rehabilitation and pollution control. Although the Regulations on the Protection of Mine Geological Environment put forward relevant requirements for the restoration and protection of mine environment, many regulations have not been fully implemented. The relevant laws on mineral resources need to be further improved, the link of mine restoration and treatment should be set up, the original "protection provisions" should be upgraded to the level of regulations or legal provisions, and the environmental legal provisions should be coordinated to form a collaborative legal support system.

3.3 Detailed inspection and assessment of abandoned mine conditions

In the ongoing national verification of historical mines, the national database and inventory list of historical mines established only include the mine name, location, mineral species, map spot number, central point coordinates, area and other elements, with little information. On the basis of the catalog list, detailed investigation and environmental risk assessment of mining methods, land ownership, environmental problems, impact scope, ecological restoration budget and other projects should be carried out, and a series of software such as mine status distribution map and management progress map should be made to help managers timely grasp the mine overview and restoration progress, and carry out overall planning and management.