Description: Hand augering can be undertaken with a
heavy tripod and winch (such as provided by the Vonder Rig in Figure -
top left). Alternatively, very light equipment can also be utilised such
as that common in Niger (Figure - top centre). Common to both of these
rigs is the auger bit (Figure top right). A bailer can also be used to
remove the spoil form the hole in the form of a slurry. Drilling is
undertaken by rotating the auger into the ground, and adding additional
drill pipe as the hole deepens.
Capability: Hand auger drilling can be undertaken in a limited
range of unconsolidated formations i.e. non-collapsing sands and silts
and some clays. Stiff clay, gravels and hard materials cannot be drilled
unless the technique is combined with percussion drilling. Temporary
casing can be utilised with some equipment. The depth limit for hand
augering is about 20m. Diameters range from 50 to 200mm.
Locations: The Vonder rig has been used extensively in
Zimbabwe and distributed widely within sub-Saharan Africa. Hand augering
experiences have been made in Niger, Tchad, Senegal, The Gambia,
Uganda, Zimbabwe, Tanzania and Nigeria and Niger.
