Changes

{{stub}}

[[Image:Treadle_pump_icon.png|right]]

[[Image:percussion gouge.jpg|thumb|right|150px|percussion gouge]]

__NOTOC__

The Stone Hammer is a form of [[Percussion - general|percussion drilling]], used when boulders or hard clay is encountered. A hollow drill bit is attached to a hammering tool. The hammering tool consists of a heavy weight which moves up and down in a pipe. Once the bit and hammering tool are lowered into the borehole by a cable, the same cable can be used to do the hammering. Lifting and dropping the hammer drives the drill bit down. When 60cm has been drilled, the unit is pulled up to the surface to empty the hollow drill bit. The stone hammer is only successful when boulders are encountered, not in homogeneous or solid stone layers were displacement of the material is not possible.

}}

Equipment is commercially produced in western countries. Local production is possible. Percussion drilling is hard work. Use of a small engine may be appropriate.

The costs are 20-60% less then those of hand dug wells.

The cost of introduction are between US$ 15,000 - 30,000 per project, including a production drill set, drawings, hands-on training, and the first wells.

The stone hammer is mainly used in India and Nicaragua, and sometimes in Madagascar.

The percussion gouge is mainly used in western countries.

* [http://www.practicafoundation.nl/wp-content/uploads/PDF/Practica%20drilling%20Rs%20versie%201th%20september%2005.pdf Rota-sludge and Stone Hammer drilling, part one: Drilling Manual] by Practica Foundation.

* [http://www.practicafoundation.nl/wp-content/uploads/PDF/practica-production-rs-versie-1th-september-051.pdf Rota-sludge and Stone Hammer drilling, part two: Production Manual] by Practica Foundation.

== 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].

{{Joinus}}