The open pit slope stability is one of the main problems for the safe production of coal mine project. It has become the main factor of production in coal mine. Taking working face 29211 of Anjialing open pit for example

the impact of underground mining on deformation and rupture process of open pit slope is analyzed by similar material model test. Similar model tests results show that the “arch” structure formed by overburden deformation leads to a great horizontal displacement toward the free surface of slope; and it also results in varying degrees of tensile failure. When working face 29211 advancing to reasonable stopping line 2

local cracks appear in the slope rock mass. The clacks gradually run through and extend to the bottom of the slope when advancing to design stopping line. So

reasonable stopping line 2 is suitable for the location of the stop mining. The above of working face 29211 is the biggest settlement; and the maximum amount of subsidence is about 8 m. The slope which includes through cracks has an extruded trend. The results provide theoretical guidances for safety of open pit exploitation.