关键词: 矿山爆破, 露天开采, 爆破分离, 矿岩混合爆区, 台阶深孔, 精准爆破, 贫化率

Abstract: The genesis of the ore deposit in Barun Mine is complex,and the distribution occurrence and spatial morphology of orebodies are irregular.In the blasting zone,the distribution of ore and rock is often characterized by multiple ore species,multiple orebodies and mixed lithology.Conventional openpit mining makes the broken ore (rock) mixed with each other in the blast pile,resulting in ore dilution and serious loss.In view of the problems such as unclear boundaries of orebodies,orerock mixing in blasting process and difficulty in visually identifying ore (rock) during shovel loading in complex blasting zone,a separation blasting scheme was put forward,which focuses on throwing and accumulating in the middle of orebody and blasting separation into clear grooves at the junction of orebody.Through drilling rock dust detonation zone for delineating the actual boundary of ore (rock) samples,integrated application of orebody (rock) in central isochron directional casting coacervation technique,throwing and blasting separation technique of multifree surface and long time delay on the boundary of orebody,and electronic detonator precise blasting technique,etc.,the goal of orderly accumulation and clear boundary separation of ore (rock) under blasting load was realized.The technical parameters of deephole bench blasting for ore and rock separation were determined preliminarily by numerical simulation study of the particle flow analysis program PFC3D.On this basis,field blasting tests were carried out.In the filed blasting tests,the bench height was 14 m,the borehole diameter was 310 mm,the borehole row spacing was (8~10) m×6 m,and the triangular borehole configuration was arranged.The borehole on both sides of the same row next to the orerock boundary were detonated firstly,and the boreholes on the both sides of the same row across the orerock boundary were detonated simultaneously after a delay of 110 ms.The goal of accumulating in the middle of the ore (rock) body in the orerock mixed blasting zone and separating the deep concave groove at the ore (rock) boundary was achieved by the integrated application of techniques such as multiple Vshaped precise holebyhole initiation and isochronous throwing accumulation with the middle of the ore (rock) body as the zero of initiation in the blasting zone.Observation results of ore removal showed that the ore dilution rate was less than 2%.