In order to effectively and reliably implement ore caving with medium-length holes blasting,reduce boulder yield and the amount of fine ore,Sanxin Gold-Copper Co.Ltd together with Changsha Institute of Ming Research carry out the experimental study on the parameters of medium-length hole drilling and blasting.In the light of the ore/rock conditions,the crater experiments of single hole blasting and wide space multi-hole simultaneous blasting and inclined bench blasting experiment as well as theoretical investigation were made,on that basis,the parameters of medium-length hole drilling and blasting were determined preliminarily,then were optimized by orthogonal blasting experiment.The recommended blasting parameters suited to the mine are hole-bottom distance 2.3 m,minimum burden1.3 m,and hole-bottom priming with safe cartridge.