Manual Drilling Techniques
When a borehole is drilled, different types of sediment
and rock layers can be encountered. To drill through all these different layers a range of manual drilling techniques have been developed and are used around the globe. In each case the drilling technique must (a) break or cut the layers, (b) remove the cut material from the hole, and (c) if
necessary provide support to the walls of the hole, to prevent collapse during drilling. Each drilling technique has been developed for either one or a range of specific sediment and rock types. In some situations, complementary drilling techniques can be used together for a single borehole.