The development of the mining industry has encountered a bottleneck. "14th Five-Year Plan" focuses on industrial transformation

CAI Meifeng pointed out that the open-pit mining should always put the stability maintenance of stope and dump slope in the most important position, and take effective monitoring and control measures to avoid the occurrence of slope landslide, tipping, collapse, debris flow and other disasters. These accidents will cause devastating damage to the natural ecological environment, vegetation, building facilities and people's living environment. In the process of underground mining, it is necessary to use filling method and other means to deal with the goaf well, effectively monitor and control the mine pressure activity, and avoid the occurrence of serious environmental damage disasters such as roof collapse, roof collapse, surface subsidence and breaking through caused by the existence and instability of goaf.

"Open-pit mining has a large impact on the environment and can cause many types of disasters. From the perspective of environmental protection and ecology, open-pit mining should be changed to underground mining as much as possible." CAI Meifeng said.

Land reclamation is the main measure of mine ecological restoration, which serves the two goals of environmental remediation and agricultural land protection and restoration.

CAI Meifeng said that land reclamation technology can be mainly divided into physical engineering technology, chemical technology and biotechnology three categories. Physical engineering technology is the main means of mine environment and land regulation. Including: surface shaping engineering. Some measures such as filling, backfilling, stacking and leveling are adopted to sort out and repair the terrain and landform of the reclaimed land, so that it can meet the requirements of the natural environment of the mining area and the use of the reclaimed land. Dig deep and pad shallow works. The large area of local water subsidence is dug deep for fish farming, lotus root planting, etc., and the excavated soil is used to pad the small area of subsidence to form agricultural land. The simple planting agriculture before subsidence will be transformed into ecological agriculture combining planting and breeding. Tailings reclamation project. Tailings belong to inorganic substances, do not have basic fertility, can be treated with soil covering, soil mixing and other methods for land reclamation, vegetation greening. There are also some necessary engineering measures, such as slope cutting and unloading, hanging nets and anchor rods, building retaining walls and other slope stability measures, cutting drainage to reduce soil and water loss and covering measures.

The main function of land reclamation chemical technology is to improve soil. For acidic soil, industrial wastes such as tailings and coal ash are used to reduce soil acidity. Alkaline soil or soil with high ph value, using humic acid and other substances to improve; Use organic fertilizer or inorganic fertilizer such as nitrogen, phosphorus, potassium to promote soil ripening and increase soil fertility; For toxic tailings and waste and contaminated land, topsoil cover is generally carried out first.

And land reclamation biotechnology is mainly forest and grass planting. In the selection of tree species and grass species, it is necessary to consider the drought resistance, cold resistance, barren resistance, growth and development speed and certain soil improvement effect of tree species and grass species according to the local natural climate conditions and rock and soil composition. The existence of earthworms can improve the soil structure, increase the ability of soil to retain water and fertilizer, and can also apply mycorrhiza, enzymes and other microorganisms to improve abandoned land. In reclamation areas with good ecological environment, emphasis should be placed on the adoption of biotechnology, the protection of pre-harvest habitat and the restoration of post-harvest habitat. More attention should be paid to the protection of habitat in the fragile area of ecological environment, and more attention should be paid to the ecological benefits to improve the ecological environment in the mining area when the reclamation work is carried out after harvest.

When it comes to the integrated technology of environmental remediation and ecological restoration, CAI Meifeng believes that ecological restoration takes pollution control, ecological value, biodiversity, environmental benefits, landscape improvement and other objectives and evaluation indicators. The main technologies are:

01. Contaminated soil treatment technology

It mainly includes physical, chemical and biological repair techniques. Physical restoration includes filling method, soil change method, guest soil method and deep ploughing method. Chemical remediation changes soil properties by adding chemicals; Bioremediation uses microorganisms and plants to remove harmful pollutants from the soil.

02. Land remediation and rehabilitation technology

The topsoil stripped in the mining area at the initial stage, including the topsoil of cultivated land, can be used for the restoration of the mining area in addition to filling the surface holes formed by mining in the environmental remediation after mining. According to different conditions, measures of land regulation and soil cover should be taken to restore the function of cultivated land.