African Borehole
Drilling

Email: info@abdrilling.co.za
Cell: 082 448 8272
082 335 8012

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Water Boreholes

Siting of a borehole needs to be selected.

Once a decision is made to drill we have to decide where to drill. We do offer a non-scientific method of water divining / dowsing. The diviner’s site selection has to be indicated using a marker. This water divining technique has been used and practiced throughout history.

The drilling method is usually known as DTH drilling, “down the hole” air flush rotary percussion. We drill the borehole to the required depth, while monitoring the water levels. We use either air flushing or mud flush drilling. Most of the time we use air flushing. This is compressed air to drive the drilling tools attached to rotary drilling rig. The air allows the drilling residue to be flushed out of the hole, to continue drilling.

A by-product/ bonus of using air flush drilling is that once water is found it is also driven out of the hole. We monitor the flow of water coming from the hole and use this prediction to estimate the water level, the water quantity and the re-charge rate of water in the borehole.

Casing to prevent collapse of the water borehole is installed to solid the formation. Depending on the water borehole being drilled, we install temporary steel casing to stop collapses during drilling. The steel casings are screwed together to support the side of the boreholes and enables drilling to continue into the harder quartzite etc. The information about the casing requirement can often be supplied about the site prior to drilling.

Once the drilling has been completed, the tools and casing is removed. The borehole is then constructed by installing 3 meter lengths of screen and casing with a diameter of 100mm into the hole.

Determining the yield of the borehole.

The accurate yield of a borehole can be determined by an aquifer test. This involves installing a test pump to pump the borehole for a period of time at a given rate, whilst recording the drawdown. An alternative method for determining a yeild of a borehole is to accurately quantify the blow yield while drilling or air flushing.

Water borehole drilling seem invasive but once it has been drilled, there is very little visible sign of the borehole. It is terminated within a purpose made poly well head sump. This is a sealed manhole 600mm x 450mm in dimension which is covered with a manhole cover. These can be simple lightweight steel covers through reinforced weight rated covers to allow traffic to pass over the borehole.

Equipping the water borehole.

Pump work is installed into the borehole using specific pumps to supply water for any number of applications. We do not offer these services but would recommend an installer.