Current status and progress on overburden and surface damage and prevention technology of high-intensity mining

With the improvement of mining technology and equipment,the intensive production and intelligence of coal mine is getting higher and higher,and the working face of high-intensity mining represented by fully mechanized top coal caving and large mining height support is increasing. It is of great significance to study the negative external influ- ence and prevention technologies of overburden and surface failure under high-intensity mining for the coordinated de- velopment of coal mining and ecological environment. Based on the analysis of the definition and main technical char- acteristics of high-intensity mining,the current status and progress on overburden failure caused by longwall high-intensity mining are expounded,including the theoretical analysis of failure height of overburden,critical mining degree and its criteria of overburden failure,calculation method of overburden failure height,and the formation mechanism of overburden “two-zone” failure mode. The paper mainly studies the failure transfer process of overburden,puts forward the criterion of full mining degree of overburden failure and the calculation method of its height based on the failure transfer process of overburden failure,and reveals the formation mechanism of overburden “two-zone” failure mode un- der high-intensity mining. Then,based on a large number of measured data,the surface movement characteristics of high-intensity mining are summarized from the aspects of surface cracks characteristics and the surface movement and deformation,and the negative external influences of high-intensity mining on overburden and surface water resources, land resources,surface eco-environment,buildings (structures) and other aspects are discussed. Based on its negative external influence induced by high-intensity mining,the prevention and control technology of overburden and surface damage in high-intensity mining and its progress in China are analyzed,the prevention and control ideas of mining damage in high-intensity mining is put forward. The results show that the high-intensity coal mining area in China will focus on the integration of negative external impact of mining,prevention and control,ecological environment monito- ring and protection technology,and the in-situ protection of eco-environment under high-intensity mining will be the future development trend.