Types and prevention of geological hazards in metal mines

Main types of geological hazards in metal mines

Common typical metal mine geological disasters include: ground collapse, landslide, collapse, debris flow, mine water inrush, soil erosion, three wastes pollution, tailings dam break, endemic diseases, mine earthquake and so on.

1. Ground collapse:

With the different burial conditions of ore bodies, the morphology and development degree of ground collapse are also different. For example, the ore bodies are shallow buried and the occurrence is gentle, the phenomenon of ground collapse is relatively common, and the subsidence area is sheet-like and large. While the ore body is buried relatively deep, due to the lack of timely backfilling, or the lack of retaining pillars in the goaf, or the loss of supporting ability due to pillar damage, it will also cause a certain level of ground collapse, but the general collapse area is relatively small. This kind of disaster can not only lead to the collapse of the roadway directly, but also make the atmospheric precipitation and surface water pour into the pit along the collapse crack, resulting in mine water inrush and other disasters. According to the characteristics of subsidence, it can be divided into: ground subsidence and ground subsidence.

(1) Ground subsidence: refers to the slow, large-scale uneven subsidence of the ground, with an area greater than 1km2, silent and shockless, and mostly in the shape of an oval basin, with local ground collapse pits or butterfly shaped water depressions.

(2) Ground collapse: refers to the phenomenon of sudden local ground subsidence, distributed above the goaf or in the ground subsidence area, with sudden outbreak, sound and earthquake, small collapse area, large depth and so on.

2, landslide, slope instability, field storage instability and collapse:

Mining induced landslide is one of the most typical disasters in metal mines, which is characterized by large scale, high frequency, long duration and great destructiveness. According to the induced factors of landslide, landslide can be divided into three types: open mining landslide, waste rock and slag field landslide and waste rock and slag loading induced landslide:

① Open mining landslide: This disaster is the landslide caused by the instability of the stope slope due to the imbalance of mining and stripping, the slope Angle is too steep and other reasons in the process of open mining.

(2) Waste slag field landslide: It is a landslide formed by the slope instability of the waste slag field in the mine for a long time. The waste slag is piled on loess, residual slope deposits or loose materials for a long time, and the foundation is not established on the original rock. The slope deformation and creep caused by loading will also infiltrate into the ground, causing soil and water pollution.

(3) Instability of the field reservoir: Such disasters are mainly caused by the artificial debris flow formed by the dam break of the tailings reservoir, which is a disaster of greater harm, not only causing casualties and property losses, but also causing great damage and pollution to the natural ecological environment.

(4) Collapse: in metal mines with universal, multiple, small scale, but the characteristics of heavy casualties, mostly because of the lack of scientific and rational design and construction, mining operation surface is too high and steep.

3, pit rock burst (mine shock) and mine earthquake:

Rock burst in the pit means that the surrounding area of the mine and the surrounding rock of the top and bottom are strongly compressed under strong stress. Once the free surface appears due to mining and hollowing, the sudden release of rock ground stress may occur, resulting in a large number of ore rocks breaking into fragments, and a large number of jets and explosions into the pit, bringing harm and disaster to the mine.

Mine earthquake refers to the earthquake induced by mining activities, shallow focal point, great harm, small magnitude mine earthquake can cause serious damage to the underground and the surface.

4, mine water gushing and sand gushing mud:

This is the most common metal mine geological disaster, sudden strong, large scale, serious consequences, especially in the production process often due to the insufficient estimation of the amount of water in the mine, the mining process to punch through the old hole, through the permeable fault, the sudden water storage cave or underground river, resulting in a large influx of groundwater or surface water.

Sand collapse and mud gushing are often associated with mine water inrush disasters. The sediment and rock debris filled in the cave influx with groundwater, and some permeable faults and ground fractures often cause shallow Quaternary sediments to flow into the pit with the surface runoff. The result is that the tunnel is blocked by sand, the machinery and personnel are buried by sand, and even the mine will suffer a devastating blow in serious cases.

5. Waste water pollution:

The wastewater of metal mine mainly comes from mining wastewater, tailings wastewater and tailings reservoir percolation water, which is another important form of geological disaster of metal mine. It causes serious pollution to the environment and harmful effects on human health.