The Coal Mining Model Under Slippery Slope in Yiminhe Open Pit Coal Mines

To study the unloading of in situ rock stress in coalmining process, mechanics analysis has been carried out, according to which, a stress unloading arch tends to come into being where the slopes are of short strike length. Due to the differences existing between the reserved supporting body and the backfill supporting body, the combined arch walls are characterized with asymmetric property, coordinate deformation property and hierarchy. And on the basis of the rock rheology and timeliness strength, the instability criteria for weak-layered slopes are provided here. By applying unloading analysis system and the numerical simulation software, we probed into the unloading timeliness length for mining slopes located in Yiminhe surface coal mine as well as the X-axis creep displacement occurring at the slope foot under the influence of unbalanced stress. And based on these facts, we proposed a resource recovery plans specifically drawn up for the slippery areas. The research results indicate the following conclusions: (1) there is a linear relationship between the timeliness length of unbalanced stress unloading and the mining parameters (mining depth and width), so the linear gradient increases with growing mining depth and width; (2) with growing mining parameters, the increase of X-axis creep displacement at slope foot shifts from linear function to quadratic function; (3) by adopting short working line and intense working face advance, it is highly probable to recover a total amount of 3.5 million tons of coals on condition of stable slope.