Mine geological environment ecological restoration

China is an important producer and consumer of mineral resources, and the exploitation and utilization of mineral resources will inevitably bring negative impacts on land, ecology and environment. For example, coal gangue mountains occupy land, land subsidence, landform landscape changes, toxic gas emissions and soil pollution. The ecological damage of mine geological environment ecosystem is inevitable in mining activities. Therefore, the ecological restoration of mine geological environment is one of the key points of territorial ecological restoration.

1. Mine geological environment problems

Mine geological environment refers to a relatively independent environmental system in which the material exchange and energy flow between the surface layer of the lithosphere and the components of the atmosphere, hydrosphere and biosphere in the mine that has been exploited, is being exploited or is about to be exploited. This system is based on the lithosphere and dominated by the exploitation of mineral resources, which constantly changes the geological environment of the natural environment balance of the lithosphere on the earth's surface.

The exploitation of mineral resources has caused, produced and intensified the geological environment problems of mines, and their types, manifestations and severity, etc. It is closely related to the type of mineral resources developed (oil and gas, coal, metal minerals, stone, cement limestone, brine salt ore, etc.), development mode (open-pit, well mining), regional geological environment conditions (mountain type, Loess plateau type, Gobi desert type, plain basin type), mining scale and other factors (Xu Youning, 2008).  Take positive measures to protect, mitigate and reduce the negative impact of mining activities on the geological environment and promote the sustainable development of the mining industry (Department of Geological Environment, Ministry of Land and Resources, 2002).

In essence, mine geological environment and mine environmental geology are different from each other and have a lot of connections. Many scholars believe that mine geological environment should refer to the primary geological environment, and mine environmental geology should refer to the environmental problems generated by mining activities.

According to different classification principles and purposes, there are different classification systems for geological environment problems in mines. Because the source is mining activities, its characteristics are distinct, the occurrence and development are regular to follow. From the time point of view, the mine geological environment problems are frequent, if not repaired, the duration exceeds the mining and settling time. From the perspective of types, the mine geological environment problems are various, including the common geological environment problems such as debris flow, collapse and landslide, and the mine unique geological environment problems such as mining collapse, tailings dam break, mine water and soil environmental pollution. In terms of control, the geological environment of mines is controllable, and its exploration, construction, mining and reclamation activities are selective and strictly regulated by national laws and regulations.

The mainstream classification of mine geological environment problems is based on the similarities and differences of mine geological environment objects, and its purpose is to investigate and study the mine geological environment for public benefit. It follows the principle of practicality and scientificity, and divides the mine environmental geological problems into three types and many manifestations according to the results of mining activities.

(1) The problem of mine resources

It mainly refers to the problems of occupation and destruction of surface construction resources or underground mining resources due to mining activities, including the problem of mine closure, mine construction occupation, coal gangue discharge and so on. This type of problem focuses on the resource problems in mining activities and makes little distinction in geological objects, mainly considering the overall volume change, storage and management planning, and is similar in ecological restoration ideas and ecological restoration purposes.

(2) Mine hydrogeology problems

It mainly refers to the change of surface water system structure, water quality and water quantity affected by mining activities, as well as the change of groundwater structure, water quality and water quantity, including the influence of underground water permeation and water inrush. This type of problem is related to the mine hydrological environment, considering the change of water body within the influence range of mining and its impact on the mine ecosystem, including people, resources and environment. It is a relatively independent type with special ecological restoration measures.

(3) Mining surface geological disasters

It mainly refers to mining induced geological disasters such as collapse, landslide, debris flow, mining collapse, tailings dam break, coal gangue mountain spontaneous combustion and other mining specific geological disasters. This type of problem refers to the geological disasters on the surface of the mine, and rarely involves the mining and safety thinning problems in the mining process such as underground gas and coal dust explosion or sheet roof collapse, and the main type is the common geological disasters on the surface.