Application research of slope monitoring and treatment technology in ecological restoration of open-pit coal mines in alpine mining areas

Slope treatment is one of the important contents of ecological restoration in open-pit mines. Taking Juhugeng Area, Muli Mining Area, Qinghai Province as an example, this paper systematically studies the identification, monitoring and treatment of slope problems in open-pit coal mines in alpine mining areas. The development characteristics and stability of unstable slopes in the mining areas are studied by means of remote sensing, geophysical prospecting, drilling and surface measurement. The results show that an unstable slope exploration and monitoring system of “aerospace-low altitude-ground-time” is established with remote sensing technology as the core, supplemented by conventional surface monitoring, geological survey, geophysical prospecting and drilling. The development characteristics and stability of unstable slopes in the mining area are determined. It provides a basis for targeted slope treatment in ecological restoration and management of mines. Using the high-risk slag hill load reduction and slope reduction treatment technology, the slope steps are cleared, the disasters such as pumice and collapse are eliminated, the slag hill slope is cut and unloaded, and the mining pit slope and slag hill slope are stabilized. Taking the south slag hill of Juhugeng well 4 as an example, according to the high-density electrical method detection and drilling verification, two slip surfaces of the permafrost upper limit and the boundary line between the slag soil layer and the original pit bedrock are identified. It is determined that the excessive load of the trailing edge is the main factor leading to the landslide. The treatment scheme of “trailing edge load reduction + slope reduction + water system connectivity + comprehensive monitoring” is adopted. After treatment, the load on the leading edge of the slope is eliminated, and the stable site conditions for the later vegetation regreening are provided. Multi-stage dynamic monitoring shows that the trailing edge of the slope has been stabilized. Slope monitoring and treatment technology has been widely used in ecological restoration and management of Muli Mining Area. The slope control of slag hill slope after treatment is less than 26°, which effectively eliminates the influence of unstable slope on restoration and management, and ensures the effectiveness of mine ecological restoration and management.