摘要
通过成本利润平衡计算出两种底部结构的平衡品位，依据矿脉品位与平衡品位对比，选择底部结构（型式）．
The balance grades of two kinds of bottom structures are calculated from cost - profit balance. The different bottom structures may be selectcd based on the comparison between the ore vein grade and the balance grade.
