我要做的就是，选择一块够硬的石锤，这次我选这块是个头有板球大小的石英岩卵石。先挑个地方锤下去，接着我就开始从这地方开始凿了。

And what I do is, I select a hard stone hammer, in this case a quartzite pebble about the size of a cricket ball, and I elect to hit it in one place - and this is where I start to knap.

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介绍了用于全面钻进的YZX127型液动潜孔锤的结构特点、性能参数、室内岩样实钻试验效果，展望了其广阔的应用前景。

YZX127 hydro hammer used for full face drilling is described with its structural characteristics, performance parameters and laboratory test results as well as the application prospects introduced.

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本文论述了潜孔锤钻进的岩石破碎机理以及影响潜孔锤碎岩效果的因素。

This paper discusses the rock crushing mechanism of DTH hammer drilling and factor influencing the effect of DTH hammer broken rock.

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