ELEMENTARY ANALYSIS ON THE MECHANISM FOR COLLAPSE OF MINED-OUT AREA IN COAL MINES,SHANXI PROVINCE

Collapse of mined-out area in coal mines is the chief geologic disaster in Shanxi Province.The developing level for collapse of mined-out area depends on internal and external causes.The internal causes include the background con-ditions of geography and geological environment.The external causes come from human engineering activities.Internal causes decide the distribution of the collapse of mined-out area, while external causes control its developing level.