Percussion Drilling - an overview
2006-9-12u2002·u2002The percussion drilling itself is classified as top-hammer drilling (THD), down-the-hole (DTH) drilling, and rotary drilling (RD) rigs, depending on the operating method used (Song et al., 2016).Fig. 2.7 shows various methods. In general, THD is used mostly for mining and civil blasting works, for which the drilled hole is restricted to a length of 40 m at the most.
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