Sino露天磁铁矿台阶爆破方案的确定

Bench blasting scheme of Sino open-pit magnetite mine determination

为确定澳大利亚Sino露天磁铁矿台阶爆破的排距和孔距,运用Holmberg&Person公式对钻孔爆破岩体损伤范围进行估算,通过迭代法确定椭圆损伤区的长短轴长度。使用动力分析软件LS-DYNA模拟5.5m(排距)×5.5m(孔距)、5.0m(排距)×6.0m(孔距)两种网孔布置方案的岩体破碎效果,结果表明:采用5.5m×5.5m方案时,炮孔之间存在未损伤区,易产生大块,后排孔起爆后出现应力集中现象。采用5.0m×6.0m方案时,爆破能量利用均匀,岩体破碎充分,是比较合理的排距、孔距参数,该方案应用于澳大利亚Sino露天磁铁矿台阶爆破,取得了良好的爆破效果。

ABSTRACT ： In order to determine the row spacing and the hole spacing of bench blasting in Sino open-pit magnetite mine in Australia, Holmberg ＆ Person formula was used to estimate the blast-induced damage zone and iteration method was used to determine the major axis and minor axis of the ellipse damage zone. LS-DYNA software was used to simulate the crushing effect of two different blasting schemes, which were 5. 5 m× 5.5 m and 5. 0 m× 6. 0 m（row spacing× hole spacing）. According to the simulation results, while the 5. 5 m×5. 5 m blasting scheme was used, there was no damage range between holes, boulders were easily formed, and stress concentration appeared after initiation of the second blastholes. While the 5. 0 m× 6. 0 m blasting scheme was used, blasting energy was uniform and rock mass were fully broken, which indicated that it＇s a reasonable blasting scheme. It was applied in Sino open-pit magnetite mine and a good result was achieved.