Research On The Prediction Of The Opencast Mining To Underground Mining High Slope Stability

Generally, a slope whose height is more than 100m is defined as a high slope in mining system,. Many opencast mines begin to turn to underground mining one after another due to facing a common problem that the cost of stripping ratio and stripping rising lead to the increasing costs of opencast mining with the extension of mining. For gobs destroy the slope structure, the slope stability was affected. Therefore, much more attention must be paid to the high slope stability of opencast mining to underground mining.High slope of opencast Shirengou iron mine to underground mining was taken as an example. Through the indoor rock mechanics test, parameters of rock mechanics was indentified, and mechanical parameters of rock slope was determined according to the method of strength reduction factor. High slope stability of opencast mining to underground mining was analyzed by numerical simulation with the use of ANSYS finite element simulation of large-scale numerical analysis software through the three-dimensional numerical model of high slope in Shirengou iron mine. By analyzing and calculating, underground mining had little effect on the overall stability of opencast slope in Shirengou, and high slope is stable.Before opencast to underground mining, the cover was formed by avalanche slope to reduce the slope angle so that the displacement and tensile stress of the top and the foot of the slope had a great reduction to improve the stability of high slope in mine. With the increasing depth of underground mining, the volume of gob area grew larger, the displacement and tensile stress of the top and the foot of the cover rock gradually increased, so did the compressive stress in the middle of the transportation roadway in vicinity and the amount of displacement. To achieve the high slope safety management of Shirengou opencast mining to the underground, observation and monitoring of high slope must be strengthened, focusing on the top and the foot of slope and the displacement changes of pit bottom cover.