AB Pumps also offers a number of specialist services, including dewatering, borehole logging with the use of cameras, straightness testing and casing detection.

  • Scientific yield testing of boreholes.
  • Sampling of groundwater sources
  • Dewatering
  • Specialised services
    • Down the hole video.
    • Camera logging
    • Electronic water quality measurements
    • Slug test with electronic transducers

Since 2000 AB Pumps has been playing a major role throughout South Africa in the groundwater environment.  We have also worked in neighboring countries. During 2008 and 2009 we have also been used by various mining groups.

Aquifer test of Boreholes

At AB Pumps we collect the necessary data at each borehole for interpretation purposes

        In order to determine the possible long term sustainable pumping rate

        For this purpose we use DWAF guidelines.

Aquifer testing of Boreholes

The problem

The problems facing every borehole/aquifer user:

1)       Limited water resources

2)       More and more water required annually

Reasons for doing a yield test

Drought conditions worldwide aggravate the above problems. To ensure a balance between supply and demand, a proper test should be done on the borehole .  If this balance is not maintained,  the borehole may dry up.

Where to start

Geohydrologist and clients can be assured that DWAF guidelines and the SANS 10299-4 2003 are used to ensure that our work meets the highest standards.

The client’s equipment will be removed from the borehole in order for us to install our own equipment.

Calibration and/or step tests (SDT) will be performed depending on the history of the borehole.

In both cases increasing the pump rate at specified intervals delivers the necessary information to determine the optimal water pump rate. 

Step Test

A step test is an hour-long procedure and recovery time is measured.  Usually this test is repeated 4 times per borehole.

Constant discharge test (CDT)

The information obtained in the step test is analysed and a decision made about CDT.

The project geohydrologist will make a decision as to the length of the CDT.  This varies mostly between 24 hrs and 48 hrs, but on bigger projects we have done CDT’s of up to 7 days.

During such a test the borehole must be pumped at a constant rate depending on the purpose / need for the borehole water.  At the end of this pre-defined period, the borehole needs to recover again to its original water level.   The drawdown and recovery time of the borehole is measured and plotted to see how and what the characteristics are.

Monitoring of boreholes

Sometimes more than one borehole may share  the same aquifer source. For this reason it becomes necessary to identify all boreholes in the area and make a decision as to which boreholes’ water levels need to be monitored during the CDT.

This will influence the final pump rate for daily utilization and prevent unnecessary dry periods and pump repairs.

But how safe is the water?

Samples are taken at the end of the CDT  in sterilized bottles. Macro and bacteriological analyses are requested by the geohydrologist. These samples are sent to a laboratory for analysis to determine the quality of the water.

The pH, temperature and electrical conductivity of a borehole is monitored throughout the SDT and CDT.

Some water may simply be to salty for any irrigation purposes.

Dewatering

At times an aquifer needs to be dewatered. Good examples of this are mining operations. During development stages our services for dewatering are called upon so that excess water can be pumped out of the aquifer.

Specialized services

Camera logging:

  • Mines
  • Boreholes
  • Caves
  • Tanks
  • Pipes etc.

A borehole video survey provides continuous detailed forward /side view colour visual inspection.

On-screen depth indications provides an accurate tool of valuable information on boreholes up to a depth of 300m. The video material will close the gap on uncertainty as to several circumstances:

  • Blocked boreholes / pipes
  • Locating lost tools or pumps
  • Geological inspection and logging
  • Verifying the success of repairs and cleaning operations

The capabilities of this simple optical imagistic tool are still under utilized.

Slug test with electrical transducers

A slug test is a particular type of aquifer test.  Water is quickly removed and added from a groundwater well, and the change in hydraulic head monitored through time to determine the near well aquifer characteristics. It is used to determine storability of the material the well is completed in.

Electronic Water quality measurements

During our years of working in South Africa, we have recognized the need for electronic water quality measurements (especially in the monitoring of boreholes).

This can include pH, temperature, electrical conductivity and depth measurements, all of which are logged electronically on a continuous basis.  Parameters can be changed from 0.5 second intervals to hourly intervals.

We stock several of these units that are downloaded to a computer upon completion of the project.

These units are mainly used to monitor boreholes.

Installing of piezometers

Geohydrologist will request this services from time to time based upon the case study.

This is a handy tool for measuring water levels at any stage to identify water aquifer problems that may arise.

Our fleet

AB Pumps uses a fleet of at least 9 trucks so that we are able to service all clients at our earliest convenience.

Man trucks,  Samil 20’s,  Samil 50’s and Samil 100’s make testing of boreholes easier and faster. Each unit has  an electrical hydraulic winch for removing and installing pump equipment.

Our trucks are load-tested and cables are certified by suppliers.

Out trucks are equipped to the strict specifications of mining companies. This includes lock-out procedures and belt guards.

Testing units are of different types as the need depends on how much water is going to be pumped and from what depth.

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