Changes

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

Jetting is also 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).

==Suitable conditions==

Suitable for weakly cohesive sands and silts. Manual jetting is generally used up to depths of 35 meters.