所有疏松的物质，例如，被移动和挖掘矿床结构外层中的沙砾。

All loose materials, i. e. gravel fills within the structure outside perimeter down to bedrock have been excavated and removed.

youdao

所有疏松的物质，例如，被移动和挖掘矿床结构外层中的沙砾。

All loose materials, i. e. gravel fills within the structure outside perimeter down to bedrock have been excavated and removed.

youdao