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[[Image:Drill bits and valves.jpg|thumb|right|150px|Drill bits and valves]] __NOTOC__ The Baptist well drilling method is a simple manual drilling method based on the [[Sludging - Asian Sludge|Asian Sludge method]]. The method to drill water wells, meant was developed to be applied used by very poor villagers in developing countries, who quickly learn how to drill their wells themselves. The Baptist drilling rig can be built in any ordinary arc welding workshop and materials for a basic version costs about 150 US$ (2006 prices). In suitable conditions, boreholes over 100 m deep have been drilled with this method.

== History and social context==The method was developed by Terry Waller, a North American Baptist missionary, in Africa and Bolivia. It applies some of the same principles used in mechanized commercial well drilling, but does so using the simplest, most available and cheapest possible materials.

The Rural people in developing countries often cannot afford to have specialists drill or dig wells for them. This method was developed by Terry Waller, to provide poor people with a North American Baptist missionary, in Africa and Boliviaway to help themselves with their water supply. It applies some of the same principles used in mechanised commercial Having built their own well drillingand pump, but does so using the simplest, most available and cheapest possible materialsusers become independent from external help for their water supply.

Rural people in developing countries often cannot afford to have specialists drill or dig wells ==Suitable conditions ==Suitable for themunconsolidated formations: Sand, silt and clay. This method was developed to provide poor people with If rotated (including a way drill bit) it may be possible to help themselves with their water supplypenetrate softer-consolidated formations such as stiff clays, soft sandstone, and weathered laterite. Having built their own well and pumpIt will not, however, users become independent from external help for their water supplypenetrate hard [http://en.wikipedia.org/wiki/Igneous igneous] rock or [http://en.wikipedia.org/wiki/Boulder boulders] (e.g. in ancient river beds).

== Suitable Conditions ==A hybrid between sludging and percussion drilling, this method permits In the unconsolidated formation types of Bolivia wells are drilled to drill through all kinds depths of loose [http://en.wikipedia.org/wiki/Alluvial alluvial] soils, sands, silts 20 and clays, as well as “soft” rocks, like light [http://en.wikipedia60 meters on average.org/wiki/Conglomerate_(geology) conglomerates], In the consolidated volcanic ashesformations of Nicaragua, some calcareous rocks Ethiopia and weathered materialsKenya well depths range from 10 – 15 meters on average. It will notIn exceptional conditions, however, penetrate hard [http://en.wikipedia.org/wiki/Igneous igneous] rock or [http://en.wikipedia.org/wiki/Boulder boulders] (e.g. in ancient river beds)boreholes up to 100 m deep have been drilled with this method.

{{procontable | pro=- Very simple and cheap equipment . <br> - Easy to handle and a temporary casing is normally not needed. It is possible to construct the drilling equipment locally.<br>- continuous movement (compared to [[Hand auger - general|augering)<br>]])- small diameter borehole possible <br>- Does not clog quickly in clay soils- No need for mud pump and tower<br>- Long extensions of the drill stem are possible<br>- Caving resistant borehole<br>- Can Possible above and below the water table |con= - The borehole stays open by water pressure. To prevent collapsing, fluid-drilled boreholes must be mechanizedkept full of water during the entire drilling and well installation process.<br>- Possible above Coarse gravel and below other highly permeable materials (cracks in the formation) cause loss of working water table| and cannot be drilled. If very fine sands (quick sands) are encountered in the first three meter of the borehole, a temporary casing and swell clay are needed on the outside of this casing to prevent collapse.<br>con=- Suitable for unconsolidated rocks only (sand, silt, clay)<br>

- In wells deeper than 20m, a lot of manpower is needed to pull the rope}} 

Like in [[sludging]], the drilling process is continuous: the drill bit is normally not removed from the borehole until it is finished. The broken-up material is pumped to the surface in the drilling liquid (mud), so there is no need for a separate mud pump. Instead of using a hand as a valve on top of the drill pipe, as is the case for sludging, the drill bit itself doubles as a foot-valve. The operator’s hand does not have to reach the end of the drill pipe, which means drill stem extensions can be several meters long.

Percussion action is performed by lifting the drill stem with a rope over a pulley, attached to a simple derrick, made with whatever available wood or bamboo poles.

The borehole diameter is kept as small as possible in order to remove a minimum of material and hence advance rapidly. Drill bits are based on 1¼” (32 mm) internal diameter galvanised iron plumbing accessories and the well is cased with cheap 1½” (39 mm) PVC pipe (SDR 41 – drainage quality). Such casing can accommodate up to a 1¼” (external diameter) PVC piston pump.

The main drill tool consists of a 3 m length of 1¼” (32 mm) iron or galvanized pipe with a bit/valve. For extensions of the drill stem, ordinary plumbing PVC pipes (SDR 26) with glued-on thread adapters have been used successfully in holes up to 30 m deep. Over 100 m depths have been reached using heavier PVC pipes (Schedule 40 or 80), and cutting thread directly into the pipe. The use of PVC drill stem keeps total weight of the rig low, even in deep holes. Therefore, no lever is needed to lift it and stroke-length can exceed a metre if so required. The PVC drill stem also significantly reduces the cost of the equipment. On the other hand, it excludes the use of rotary action.

No temporary casing is used. The borehole being kept full of mud and the “caking” of mud into any unstable sand layers, as a consequence of the percussion action and friction of the smooth lateral edges of the bit, is normally sufficient to stabilize it. Drilling mud is evacuated from the borehole after casing the well by pouring or injecting water into the casing (backwashing).This technique adapts best to sand, loam and light rock. The standard drill bits also work through sticky and even consolidated clays. Nevertheless, best results in varying conditions are obtained with an array of different bits:* Moveable point bits for general purpose and clay-holding soils: the moving stem of the heavy dart helps to keep the footvalve clean.* Fixed point bits for sandy and rocky layers, where there is no risk for sticky material to obstruct the footvalve.* Open-ended (hollow) bits without a footvalve (pure sludging) for layers of pure clay or gravel. In these conditions the presence of a footvalve may slow down progress, since clay has to be pounded into suspension and stones have to be ground to small pieces in order to enter the drilling tool through the footvalve.

====Manufacturing====

Baptist well drilling is used in the following countries:ColombiaBolivia, Nicaragua, BoliviaKenya, Ethiopia, Mozambique, Cameroon, Zambiaand Sri Lanka.

* [http://geocities.com/paulcloesen/DocBautista/BaptistWellDrillingManual.pdf Baptist well drilling on in Bolivia], manual produced by Terry Waller. 

*[http://geocities.com/paulcloesen/VideoBautista-EN.htm Complete set of movies on Baptist well drilling], compiled by Paul Cloesen. The same movies can be found [http://www.youtube.com/view_play_list?p=370A3B99269BC4FE here on YouTube]. * [http://geocities.com/paulcloesen/DocBautista/BolivianBaptistDrilling.pps Powerpoint presentation on Baptist Drilling] by Terry Waller. == Acknowledgements==* The basis for the material on this page was obtained from a desk study shortly to be published on the website of the [http://www.practicafoundation.nl/ Practica Foundation], and from the [http://www.rwsn.ch/ Rural Water Supply Network], and specifically its [http://www.rwsn.ch/prarticle.2005-10-25.9856177177/prarticle.2005-10-26.7220595116/prarticle.2005-11-15.6127855822 manual drilling section].

==External Links==*[Water for All - Website of Terry Waller on Baptist well drilling - http://www.geocities.com/paulcloesen/DocBautista/BolivianBaptistDrilling.pps Powerpoint presentation on Baptist Drilling] by Terry Waller.h2oclubs

 *Technical note 43. Simple drilling methods, Bob Elson and Rod Shaw, WEDC - An overview of simple drilling methods [http://www.geocitieslboro.ac.comuk/well/leonvidaresources/Leonvidatechnical-briefs/Goyena43-simple-drilling-methods.htm Baptist technology in Nicaraguapdf Download]*. Website of [http://www.emaslboro.ac.uk/well/resources/technical-internationalbriefs/ Loughborough University Technical Briefs section].de EMAS rural water supply solutionsWebsite of [http://www.lboro.ac.uk/well/ Loughborough University WELLS] . *[http://www.lifewatergeocities.cacom/leonvida/ Lifewater Canada - Simple hand-pump and well drilling Leonvida/Goyena.htm Baptist technologyin Nicaragua]