Abstract: In recent years,the international market price of iron ore drops large,the economic benefits of iron mines in our country are influenced seriously,quite a number mines are shut down or closed.Under the current market conditions,the original design scheme of mining and ore dressing can be optimized to some extent based on the the distribution conditions of the ore-bodies and mining technical conditions of different mines,so as to improve the main economic and technical indicators,reduce the mine production costs and obtain the better economic benefits.Taking a mine located in the northwestern of our country as the study example,the existing design scheme of mining and ore-dressing of the mine is analyzed in detail,the economic and technical evaluation results of the scheme show that the net present value of the scheme is negative,which indicated that the scheme is not feasible.Based on the above analysis results,according to the ore-body distribution characteristics,the existing design scheme of mining and ore-dressing of the mine is optimized by changing mining scope and design production scale,adjusting some related system engineering.The mine production scale and mine development scale of the optimization scheme are smaller than the ones of the original scheme,besides that,the mine infrastructure engineering and early stage investment are both reduced,therefore,some relative economic and technical indicators are improved significantly.The study results related to the optimization on the mine design scheme of mining and ore dressing can provide some reliable reference for the similar mines.

Key words: Design scheme of mining and ore dressing, Economic and technical indicator, Net present value of scheme, Production cost