Step-by-step instructions for drilling a borehole

• BOREHOLE SITING AND DIVINING
  Siting refers to the process of selecting the most suitable drilling location with the best possibility of striking underground water. BBP will be happy to refer a diviner with excellent references to assist.

• THE DRILLING OF A BOREHOLE
  The drilling method employed is known as “down-the-hole” air flush rotary percussion. A pneumatic hammer and drill bit operated at the end of the drill pipe rapidly strikes the rock while the drill pipe is slowly rotated. The shattered splinters of rock are removed from the borehole continuously by the air used to drive the hammer. The drilling process is very noisy and can be very messy (either dusty or muddy). Drilling in urban areas is restricted to normal working hours and it is advisable to notify your immediate neighbours (to close their windows) the day drilling is to commence. The client needs to identify underground water pipes, sewage pipes, electrical, telecommunication or any other pipes or cables, as the drilling contractor cannot be held liable for any damage that might occur while drilling. A domestic borehole can usually be completed within a few hours.

Drilling usually proceeds until either sufficient water is intersected (i.e., successful borehole scenario) or the client’s budget is exhausted. A domestic borehole will have an average depth of 40-70m.

• YIELD TESTING
  The accurate yield of a borehole can only be determined by means of an aquifer test (pumping test). These tests involve installing a test pump and pumping the borehole for a period of time at a given rate (yield) whilst monitoring the drawdown (lowering of water level in the borehole as a result of abstraction). BBP Drilling has their own Test Rigs, and this service forms part of our comprehensive solution.
  A Pumping Test is the process whereby a borehole is subjected to pumping under controlled test conditions in order to determine the performance characteristics of a borehole. Borehole testing aims to determine the optimum rate at which a borehole should be pumped.
  Borehole testing identifies the long term sustainable pumping rate – it is important not to over pump a borehole as it can reduce or damage the water table. Our testing includes bank certificates and yield tests to confirm the water quantity and quality.

Borehole yield is the volume of water that can be abstracted from a borehole – the maximum rate of abstraction from the borehole can be expressed as l/s, m3/hr, m3/d or m3/a. Yield testing helps to establish the safe yield of the borehole, the yield duty period and the quality of groundwater. This information is very useful in deciding on pump size and depth of installation.

• EQUIPPING OF THE BOREHOLE
  The final stage of the sequence of events is to pump and pipe (reticulate) the water from the successful borehole into your home / factory / garden. The end use of the water will to a large extent determine what type of pumping and reticulation system is to be installed. Of paramount importance to the correct sizing of the pump are the results of the pumping tests – how much water can be pumped out of the borehole for how long a period?

Most clients prefer to have a complete off the grid system. The borehole water will be pumped into storage tanks and from there connected with a switch over valve to your main supply.

A correctly sized and installed pump should last for many years with a minimum of maintenance and the extra cost of having a system professionally installed will pay for itself time and time again.

Our Drilling equipment is specifically designed and built to enable borehole drilling in residential areas without hassle.