For small rotary rock drill bits and rotary prospecting bits to cut soft, medium-hard rock.

用于中小规格冲击钻及旋转勘探钻具，凿进软岩层、中硬岩层。

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For any music other than hard rock, this room style is a happy medium.

这个类型的房间是个折衷方案，除了硬摇滚适合所有的音乐类型。

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But appropriate the blasting parameters of medium deep blasting in hard rock tunnel is always a technical problem need to be solved.

而合理的硬岩巷道中深孔掘进爆破参数则一直是需要研究解决的技术难题。

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