Abstract: According to the characteristics of the horizontal partition of surface mine，this paper analyzes the characteristics of total dumping covering，half dumping covering and whole groove of the inner dumping mode，and the formula of re-Stripping volume was obtained on the condition of total dumping covering and half dumping covering.With the basic principle of the surface mining，and according to the single and double circuit transportation distance of the inner dumping，a mathematical model with the optimized economic benefit was set up based on the groove depth，deducing the benefit formula of groove depth to maximize the economic benefits of inner dumping.Finally，the factors influencing to the groove depth are analyzed，obtaining that the inner dumping covering height in the horizontal surface mine the mining depth，the width of the pit bottom and the terminal slope angle would have a great influence to the groove depth.

Key words: Surface mine, Inner dumping, Groove depth