Abstract: In order to solve the problem of low grade of shovel-loaded raw ore after blasting caused by interlayer superposition of ore and rock in Sijiaying Iron Mine，the ore and rock separation test was carried out with the help of fixed secondary dry separation equipment in the stope. The test data show that the dry separation technology has a certain effect on the ore and rock mixture. Therefore，a mobile crushing dry sep⁃ aration equipment suitable for open-pit stope is developed，and the ore and rock mixture is separated and the process is optimized from the source of shoveling. The field application results show that when the mobile crushing and dry separation technology is used to treat the ore and rock mixture with an iron grade of about 15%，the concentrate grade can reach 24%，the ore yield can reach more than 50%，and the production cost of fine powder can be reduced by 6.02 yuan/t，which realizes the increase of production and the reduc⁃ tion of cost. It provides an effective way for the sustainable development of the mine and has popularization and application value for other mines.

Key words: low grade iron ore, mobile crushing and dry separation, ore and rock separation, indica? tor optimization