金属矿床地下开采形成的大量采空区不仅危及矿山的安全，而且对资源的充分回收造成严重的困难。

Large Numbers of cavities formed by the underground mining of metal mineral resources not only endanger the mine safety but cause great difficulties in a full recovery of the resource.

youdao

金属矿床地下开采形成的大量采空区不仅危及矿山的安全，而且对资源的充分回收造成严重的困难。

Large Numbers of cavities formed by the underground mining of metal mineral resources not only endanger the mine safety but cause great difficulties in a full recovery of the resource.

youdao