Abstract: Large-diameter deep hole open stoping with subsequent filling is a safe and efficient mining approach to utilize inclined and extremely thick orebody.Reasonable stope structure parameters is key premise to stope stability.Aiming at massive underground mining with a capacity of 10 Mt/a at Jama Copper Mine,stable zone and hydraulic radius are calculated using Mathews stability graph,and stope stability is numerically simulated using FLAC3D software to optimize the stope structural parameters with high section and large stope.Numerical simulation is operated with respect to four parameter combinations in the mining pattern of "mining one at three stope intervals".The relationship of exposed areas of stope roof,sidewall and hydraulic radius is revealed by Mathews stability graph.Results shows that stope roof span is favorable at 15 m,stope length is limited to 46 m when stope height is 100 m.When the span of secondary stope increases from 15 m to 19.5 m,the roof displacement and plastic zone volume of stope are accordingly increased.Sidewalls of trench at bottom structure have a relatively low safety factor and therefore tend to suffer a range of shear failure.Since the numerical simulation results are consistent with the evaluation of Mathews stability graph,the stope structure parameters are optimized as 45 m in stope length,15 m in the preliminary stope width,18 m in the secondary stope width,and 100 m in stope height.The research results provide theoretical support for the safety mining of the high and middle sections of the inclined extremely thick orebody.

Key words: inclined and extremely thick orebody,massive underground mining,high section and large stope,stope stability,Mathews stability graph