Control of surface movement and deformation during coordinated mining of large dip coal seams

In order to achieve the goal of reducing surface damage during coordinated mining of large dip (inclined) coal seams, taking the occurrence conditions of coal seams in a certain mine in Gansu Province as the background, UDEC numerical simulation software was used to explore the problem of controlling surface movement and deformation during coordinated mining of large dip (inclined) coal seams. The results indicate that during the mining of large dip (inclined) coal seams, the surface damage is more severe when the working face is buried at a shallow depth. As the burial depth of the working face increases, the impact on the surface gradually weakens; in the mining of multiple coal seams, the core problem of surface loss reduction in coordinated mining between coal seams is to make the surface of the working face with shallow buried depth not move or move less, make the surface further sink within the influence range of coal pillar, reduce the uneven deformation degree of surface subsidence and movement deformation, and prevent large mining cracks on the surface; the uniformity of surface movement, the degree of surface tension and the degree of surface deformation can be characterized by the coefficient of variation, the slope of horizontal movement in the tension region, the surface level, inclination and curvature deformation; the optimal fault distance of the working face controlled by surface movement and deformation under this geological mining condition is 80 m, the horizontal distance of the remaining coal pillar of 1# coal from the uphill boundary of 4# coal working face is about 71.9 m, and the distance from the downhill boundary is 39.9 m.