Abstract: In view of low rock strength and poor stability condition of open-pit slope in Miaogou iron mine, and based on systematical field investigation on engineering-geological condition, hydro-geological condition, rock mass structure, physical and mechanical properties of rock mall of the open-pit slope, the back analysis of rock mass parameters was made by applying the Geo-slope to determine the proper mechanical parameters index of rock mass, with the combination of the numerical simulation and the limit equilibrium method of the principle of the modern rock mechanics, and with rock mass parameters obtained. The study provides a basis for ensuring reasonability and reliability of the slope expansion in the mine.

Key words: Miaogou iron mine, Rock parameters, Limit equilibrium method, Back analysis