A Study of Millisecond Blasting on High Bench at Barun Iron Ore Operation

To improve the productivity and efficient of modern large-scale open-cut mines, a number technologies are developed trialed, including new blasting equipment, larger holes, high benches, air spacing, short-delay within holes. However, relative parameters need field calibration further investigation theories on these techniques required. This paper studied bench at Barun Eboxi Mine Baotou Iron Steel Group via theoretical analysis shock wave, numerical simulation, test. According to technical conditions site, three sets vertical boreholes 310 mm diameter were drilled 24 m batter; air-spaced charges set up. The digital electronic detonator was used initiate millisecond intervals. study found that under condition bench, use intermediate interval is beneficial rock fragmentation. delay time hole 3-8 ms. bottom lower explosives top upper devised for initiation optimize location. peak effective stress points 63.6%, 52.2%, 8.9% higher, respectively. test high-bench intrahole in mine shows proposed this feasible.