rock specimen是什么意思

用法例句

Based on the hydrogeological conditions,coal seam roof,rock mechanics in Wujia coalfield,author advance that safety pillar under water bodies can be shorted,mining level can be raised,and expound the way of construction.

通过对五家矿区水文地质条件、煤层顶板、岩石物理力学性质进行分析和研究 ,提出在五家矿区含水砂层下采煤可以缩小防水煤岩柱 ,从而提高回采标高。