Changes

[[Image:Jetting icon.png|right|80px]]

Jetting is based on water circulation and water pressure. As opposed to sludging, water is pumped down the drill pipe and the ‘slurry’ (water and cuttings) is transported up the borehole between the drill pipe and the borehole wall. A motor pump is used to achieve an adequate water flow. The drill pipe may simply have an open end, or a drill bit can be added. Partial or full rotation of the drill pipe can be used. Thickeners (additives) can be added to the water in order to prevent hole collapse and reduce loss of working water (drill fluid).

* [http://www.wellspringafrica.org Manuals] on Percussion drilling, well construction, manufacturing tools. Cliff Missen, Wellspring Africa, draft 4.

* [http://docs.watsan.net/Scanned_PDF_Files/Class_Code_2_Water/212.5-79WE-7794-1.pdf Wells Construction: Hand dug and Hand drilled.] Richard Brush, Peace Corps 1980.