Boreholes

We have two truck mounted drilling rigs capable of drilling to 150 and 180 metres respectively by either Mud Rotary or Rotary Percussion method. 

Cape Town is notorious for having difficult geological drilling conditions often necessitating combinations of both the above mentioned drilling techniques on a single hole.

This also involves dual casing of many boreholes, with both steel and PVC casing. Although groundwater is plentiful in the Western Cape it does involve more work than traditional methods.

 

Borehole Maintenance

Having a borehole constructed and equipped is a substantial investment and just like other expensive purchases such motor cars, it will need to be serviced and maintained regularly.

The minimum service interval should be no more than every two years.

During a service we extract the submersible pump from the borehole. The pump will then be stripped on site and inspected for wear. The two most common causes of wear in Cape Town boreholes is sand ingress into the bore and accumulation of iron oxide manganese.

Sand is often found in seepage water bore holes which are typical in Cape Town and is a normal occurrence; it can cause gradual erosion of the pump impellors. An inspection will show this, and the necessary components are then replaced.

Iron oxide and manganese deposits need to be removed, as they compromise the performance of the pump and can ultimately lead to the pump failing and causing the motor to overload and burn out. The inspection period for boreholes with such mineral content varies but if it is very high an annual inspection will ultimately save you in the long run.

At least once every four years the borehole itself should be cleaned and re-developed. This is done after the pump is removed and a high volume high pressure air hose with specialised cleaning nozzle progressively is pushed down the borehole. This cleans the screening in the borehole casing and lifts all the sediment and debris out of the hole.