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Jetting - general

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{{Language-box|english_link= Jetting - general | french_link= Coming soon | spanish_link= Coming soon | hindi_link= Coming soon | malayalam_link= Coming soon | tamil_link= Coming soon | korean_link= Coming soon | chinese_link=水力喷射 — 综述 | indonesian_link= Coming soon | japanese_link= Coming soon }}[[Image:Jetting icon.png|right|80px]]__NOTOC__ 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).

Jetting is practiced in a wide range of varieties. The most simple consists of driving a plastic pipe down with water pressure from a motor pump (no drill bit and no rotation, with the water flow jetting the sand up). The depth is limited (no drill bit and extendable pipes). Other systems make use of extendable plastic or galvanized pipes and a drill bit and are rotated during drilling. With these systems greater depth can be reached.

===Suitable conditions===[[Image:Manually rotated jetting.jpg|thumb|right|250px200px|Manually rotated jetting]][[Image:Typical drill bit.jpg|thumb|right|250px200px|Typical drill bit]]

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

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! width="50%" style="background:#efefef;" | Advantages

! style="background:#ffdeadf0f8ff;" | Disadvantages

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| valign="top" | - Very quick in fine and medium sand formations.<br>

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 ===Construction, operations and maintenance===[[Image:Jetting.jpg|thumb|right|250px200px|Jetting. Credit: WEDC.]]

All drilling equipment, except the motor pump and some valves, is locally produced.

==Costs=Field experiences===Jetting is mainly used in Niger, Chad, Madagascar, Nigeria, Senegal, Burkina Faso, Uganda, Kenya, Soudan, Benin, Sri Lanka and western countries.

==Field experiences=Manuals, videos and links===Jetting is mainly used in Niger, Chad, Madagascar, Nigeria, Senegal, Burkina Faso, Uganda* [http://www.unicef.org/malawi/MLW_resources_qualityassureboreholes.pdf CONSULTANCY SERVICES: QUALITY ASSURANCE OF UNICEF DRILLING PROGRAMES FOR BOREHOLES IN MALAWI] UNICEF, Kenya, Soudan, Benin, Sri Lanka and western countries2011.

==Manuals* Robert Vuik, videos[http://www.practica.org/wp-content/uploads/services/publications/drilling%20manuals/EN/Jetting%20manual%20drilling%20PRACTICA%20EN.pdf Jetting: Manual Drilling Series, and links==* TECHNICAL TRAINING HANDBOOK ON AFFORDABLE MANUAL WELL DRILLING]. Practica Foundation, June 2010. French version: [http://www.bsf-south-sudanpractica.org/siteswp-content/defaultuploads/filesservices/SS+Tech+Guide--Hand+Pump+Equipped+Boreholespublications/drilling%20manuals/FR/Jetting%20manual%20drilling%20PRACTICA%20FR.pdf Technical Guidelines for the Construction and Management of Borehole Hand pumps.FORAGE AU LANCAGE A L’EAU] UNICEF, April 2009.

* [http://www.lifewater.ca/manualsresources.htm ManualsLifewater Resources] on hydrogeology, well construction, all drilling techniques, hand pumps and more. Lifewater Canada, update 2004.

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

* [http://www.ghanamissionghanawashproject.org/AA%20Drilling%20Manualwp-content/uploads/2012/07/36_Conference_Paper_Manual-Drilling_Ghana_Naugle-1.pdf Professionalization of Manual Drilling Water Wells by Handin Ghana.] GWAMGhana WASH Project, Ghana. * [http://www.lifewater.ca/resources/link-drilling.htm Manuals and drilling links]. Life Water.

* [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.

* [http://www.worldcat.org/title/shallow-wells/oclc/008463099 Shallow Wells.] DHV Consulting Engineers, 1978.

* [http://www.rwsnwatersanitationhygiene.chorg/documentationReferences/skatdocumentationEH_KEY_REFERENCES/WATER/Drilling/Hand%20Drilled%20Boreholes/Human%20Powered%20Drilling%20%28Cranfield%20University%29.2005-11-15.5533687184/file pdf Human-Powered Drilling Technologies.] Richard Carter, Cranfield University, 2005.

* [http://www.rural-water-supply.net/en/resources/details/148 Drilling Boreholes for Hand pumps.] Peter Wurzel, SKAT Switzerland, 2001 - A book on hydrogeology, well construction, drilling techniques, well development.

* [http://www.drillingfab.com Drillingfab.] - Engine powered drilling equipment and small machines.

===Acknowledgements===

* [http://www.lboro.ac.uk/well/resources/technical-briefs/43-simple-drilling-methods.pdf 43. Simple drilling methods.] WEDC.

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