On the relation between words mei,mao,meng and mo;

The preventive measures of roof falling under ground production in coal mine;

Aimming at the roof falling accident in 2209 fully mechanized working face of Chensilou Coal Mine of Yongcheng Coal Industry Group,the authors have chosen the technology of injecting chemical reinforcing grout to strength the roof and ambient coal body.

Processing plan of collapse and roof fall of moving stove tunnel soft burying around rock section;

Analysis of stress arch action and preventing roof falling in laneway engineering;

The paper analyses the factor of coal mine roof fall by AHP and provides reliable theoretical basis for controlling the roof fall.

Although directional drilling technique has maturely been used in pipeline constructions, some troubles still occurred in construction courses such as drilling pipe broken, mud spillover, drilling pipe stuck and ground surface collapse.

Spontaneous combustion cause and preventing technology at high caved area in soft and extra-thick seam;