露天矿复杂矿体大方量压渣爆破试验

为研究复杂矿体大方量压渣爆破在纵深方向上的爆破质量变化和矿废混合情况，在非洲某大型露天铀矿进行了现场试验，爆破台阶高度7.5 m，炮孔18排，爆破方量35万t。结果显示，靠近渣体的爆堆（松散区）在隆起高度、块度分布以及电铲效率等方面优于远离渣体的爆堆（密实区），揭示出大方量压渣爆破效果沿纵深方向变差。爆破后，试验区块矿量总体增加14.6%，品位下降4%，废石量减少28.8%，松散区矿废互混更加明显且矿岩量增加，密实区矿岩量减少。为改善密实区爆破效果，提出采取“一个爆破区块，两套爆破参数”的策略。

Experiment on large volume buffer blasting of the complex ore body in open-pit mine

In order to study the change of blasting quality and ore waste mixing condition along the depth direction in large volume buffer blasting of complex ore-body. A site test has been done in a large open-pit uranium mine in Africa. The height of the blasting steps is 7.5 meters, with 18 rows of holes, and the blasting capacity is 350 000 tons. The trial found that the blasted heap close to the buffer (loose area) was superior to the blasted heap far from the buffer (dense area) in terms of heave height, rock mass fragmentation distribution, and shovel efficiency. It is revealed that the blasting effect of large volume buffer blasting decreases along the direction of depth. After blasting, the ore quantity in the test block increased by 14.6%, grade decreased by 4%, and waste rock amount dropped by 28.84%, the ore waste mixing is more obvious in loose areas and the ore rock quantity increased, in contrast, the ore rock quantity in the dense area reduced. To improve the blasting effect in a dense area, one blasting block and two blasting parameter strategies are proposed.