Analysis on Main Control Factors of Strip Mining in Multi Seams Based on Normal Test Design

There were many influence factors on the strip mining in multi seams.In order to study each factor affected the strip mining in the multi seams, the FLAC software was applied to simulate the maximum value of surface subsidence with strip mining in the multi seams when in a certain mining depth and with different mining width, distance between seams, lithology between seams and the different space relationship between the upward and downward coal pillars.The normal test design me thod was applied to analyze the four principal factors to the sensitive degree of the maximum surface subsidence. The principal factors in sequence would be the mining width, the space relationship between the coal pillars in the upward and downward seams, the lithology between the seams and the distance between seams.