PERCUSSION DRILLING

The process called percussion drilling was used by the ancient Chinese over 3000 years ago to provide boreholes. Seedsowers have teamed up with other volunteers from various church and prayer groups to learn the rudiments of the process so that it can be developed to provide much needed boreholes, cheaply for the rural villages in Africa. A Baptist Missionary in Boliva has refined the procedure so that the equipment required can be readily made from locally available components. He contends that a borehole using his refined procedure costs as little as $2-00 a metre sunk. This is considerably less than the general costs of sinking a borehole at present.

In January 2007, Mike Ansell of Seedsowers flew to Ethiopia to train in the revolutionary new drilling technique pioneered in Bolivia by the Baptist missionary, Terry Waller. During the trip they met up with missionary Joseph Stocker who has been working with Terry Waller for 3 years and has established a base for the charity called Water for All in Africa at Awasa in Ethiopia.

Mike, with others, have been practising the new technique on an estate just outside Exeter. They were so encouraged with the new drilling method that when the opportunity arose to learn more about the technique in Ethiopia they immediately accepted the offer.

They found the experience very worthwhile and have successfully sunk several boreholes using this technique in rural villages in Malawi.

The drilling rigs for this technique are manufactured from locally sourced 1 ¼” water pipe with a dart shaped cutting bit at the end made from old car springs. The pipe with its dart is suspended on a rope from a pulley on a tripod structure and the other end of the rope operated by a team of pullers who alternatively lift and release so that the dart bit strikes the earth thus generating a penetrating pilot hole of approximately 2” diameter.

The borehole has then to be swaged out to take a 90 mm liner. The bottom of the liner is slotted using a hacksaw to allow the new found water to enter it and a sacking filter taped over it to filter the water.

The borehole has then to be cleaned up by ‘backwashing’ it using a motorised pump or a hand pump. After this has been completed the cavity around the liner is filled in with aggregate, sand, and finally sealed with a mixture of sand and drilling clay.

The technique is so revolutionary that the rural poor will be able to form ‘drilling clubs or cooperatives’ to build their own drilling rigs and after some training drill their own boreholes. The average cost of sinking a borehole by this method is approx. $2.00 per metre. This contrasts to $200 per metre with the existing methods used.

Other pumps that have been used are the ‘Canzee’ pump supplied by Richard Cansdale of Newcastle. These pumps are all plastic and are simple to maintain. They are specially designed to have very low maintenance and can easily be maintained by the villagers themselves at relatively low cost.

Latterly, Seedsowers have developed its own Micro Pump for its installations.