Abstract: A three-dimensional stress testing was conduced at 6 points at -50 m and -100 m levels of Fengshan copper deposit by stress relief method, obtaining the 3D geo-stress data of the 6 measuring points.The results indicate that the geo-stress in the south is larger, with the biggest principal stress being about 15 MPa; and that in the north is smaller, with the biggest principal stress being about 8.0 MPa.The geo-stress in the mining area changes along with the topographic relief, and is obviously controlled by topography and geomorphology.The deadweight of the rock-mass and the tectonism are the main factors forming the geo-stress, and they have different effects on the different areas, with the south area mainly affected by tectonic stress, and the deep area mainly by deadweight.The results provide a reliable basis for the production and tunnel support design of Fengshan Copper Mine.

Key words: Mining engineering, Geo-stress, Fengshan copper deposit, Stress relief method