[[Image:Stone_hammer_well_drilling_icon.png|right]]
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The previous drilling methods are not suitable for hard soil formations, so ongoing development led to the Stone-hammer. This method consists of a heavy hammer hitting directly on a hollow drill-head. Although it does not penetrate very hard stone such as basalt, it is a tougher option than the Rota-sludge method. This technology is being refined further in India and Nicaragua.
The Stone-hammer method has won a competition for innovative irrigation technologies organized by the World Bank, Winrock and IDE (International Development Enterprises).
[[Image:Stone_hammer_well_drilling.PNG|thumb|right|150px|The Stone-hammer in India, drilling a 20 m deep well in a stony layer ]]
{| border="1" cellpadding="5" cellspacing="0" align="center"
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! width="50%" style="background:#efefef;" | Advantages
! style="background:#ffdead;" | Disadvantages
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| valign="top" | Cheaper and easier to maintain than motorized drilling rigs.<br>
Drill in very hard soil<br>
| valign="top" | Slower than motorized drilling rigs.<br>
|}
== Capacity ==
2-5 inch wells to 40 meter.
== Costs ==
20-60% less then hand dug wells.
== Applying conditions ==
<b>Cost of introduction:</b> Variable US$ 15,000 - 30,000 per project, including: production drill set, drawings, hands-on training, first wells.
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==Stone Hammer Drilling Manual==
PRACTICA foundation and ETC Energy have put together a manual on the Rota Sludge & Stone Hammer drilling: [http://www.connectinternational.nl/files/Rota%20sludge%20and%20stonehammer%20drilling.pdf Volume I Drilling Manual], [http://www.practicafoundation.nl/wp-content/uploads/PDF/practica-production-rs-versie-1th-september-051.pdf Volume II Production Manual]
== External links ==
* [http://www.worldbank.org www.worldbank.org ]
* [http://www.practicafoundation.nl www.practicafoundation.nl ]
