Bolivian Baptist Well Drilling Author of the system: Terry Waller  1,500 wells drilled in 5 years (more than 200 in 2004).  Very simple and cheap equipment. Can be made in any basic workshop. Complete set costs approx. $ 300.  Drills even light rock.  Done by the users themselves with little technical assistance.  Users teach others how to drill their own wells.

Bolivian Baptist Well Drilling Workers pulling up the drilling tool (use of a lever is not usual) Drilling liquid (light mud) is expulsed from the drilling rod itself (no need for a mud pump) Drilling stem of thick PVC pipe ( = light). (makes it possible to drill deep without a lever to lift the drill tool and to easily adapt stroke length to conditions) General View : Rope to pulley (no need for a formal drilling tower).

Bolivian Baptist Well Drilling Coupling to main pipe of drilling tool (3 metres of 1.25” galvanized iron water pipe) Internal check valve expulses the mud, loaded with clippings through the drill stem with each stroke. Dart mounted on ball that acts as check valve assures self-cleaning of mud inlet. The Drill Bit:

Bolivian Baptist Well Drilling Drilling fluid (mud) expulsed from the drilling tool itself through its vertical movement. Sedimentation pit. Heavy particles sink to the bottom. Light drilling liquid (mud) re- circulates back into the borehole by gravity. Starting the “drilling” : Long drilling tool (3 m) should be entered perfectly vertically (two helpers watching to get it right). Vertical hammering only. There is no rotating action.

Sometimes shallow water holding layers would yield undesirable water. To prevent such water from entering the well, soon after completing the drilling, the borehole is cased with a PVC tube, wide enough to accommodate the pump. This also prevents it from caving in.

Bolivian Baptist Well Drilling  Pure impact action (no rotating movement). Absence of torque permits a light drilling stem (thick PVC pipe). Light drilling stem permits working the tool with a simple pulley fixed to any kind of tripod or crossbeam Light drilling stem permits working the tool with a simple pulley fixed to any kind of tripod or crossbeam.  Clippings pumped out by movement of the drill tool itself. No need for a separate mud pump No need for a separate mud pump. Main Characteristics: AdvantagesDrawbacks Very simple and cheap equipment.  Very simple and cheap equipment.  No need for mud pump or tower.  Permits long extensions of drill stem.  Caving resistant borehole.  Easy to vulgarize.  Mechanizable.  Somewhat slower than drilling with rotating action.  PVC drill stem should be high quality. Some exercise needed to get the long drill tool right at start of drilling.  Some exercise needed to get the long drill tool right at start of drilling.  In wells > 20 metres, needs a lot of manpower to pull the rope.

Bolivian Baptist Well Drilling Variants Fixed head drilling bit Rock bits (without points, otherwise they get stuck; edge reinforced with high carbon electrode welding) Check valve inside tool Classical dart bit

Bolivian Baptist Well Drilling Variants Since there is only vertical move- ment (no rotation), the process can be mechanized. (When labour is in short supply and a lot of wells to be drilled). 3 HP Diesel Engine. Reduction of engine RPM. Turning lever with pulley, moved by the engine, pulls the rope. (Stroke height is adjusted by free length of the rope and position of pulley on the lever.)

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