Borehole Drilling


These are the four steps involved:

1) Determining the Location to Drill

Depending on your preference, we are able to recommend the services of reputable water diviners and hydro-geologists in your area. We have identified these professionals as the leaders in their fields. These introductions are independent of our services, and Hillson Drilling does not guarantee water.

In selecting the drill site, we will also consider the terrain to ensure it is accessible for equipment. Other infrastructure such as pipelines and electrical cables also needs to be considered.

2) Drilling, Installation of Casing and Hole Development

The typical mode of drilling for domestic borehole drilling is air percussion drilling. A drill bit with a 219mm diameter will be used until the topsoil and overburden rock is sufficiently penetrated. This large diameter is necessary to accommodate the installation of 177mm steel casing. This is required to prevent the borehole from collapsing, and to protect the pump from drawing sand and sediment. Casing will typically only be required for the layers of unstable overburden (from the surface to about 20m).
If required, gravel pack will as well as perforated casing will be inserted. Once the borehole is completed, the hole needs to be developed (flushed) of debris.

3) Determining the Yield of the Borehole, Pumping and Piping

This test requires the temporary installation of a test pump. The pump is operated at a scheduled rate and time, while the decreasing level of water in the borehole is monitored. Simply testing the yield without measuring the water levels is merely a test of how the pump and equipment is performing.

Having a borehole drilled is a significant investment. The water that it generates should be regarded as a substantial asset. It is worth having this asset properly tested and measured. This establishes how much water can be used sustainably, without affecting the yield. Total abstraction should be less than the recharge.

The intended use of the water and the yield will determine the type of system to be installed. Hillson Drilling can assist to design and construct the optimum system for your unique requirements. Our long-standing relationships with suppliers ensure competitive pricing on all materials.

4) Costing your borehole

Due to the many factors that determine the completion of a borehole, there is a substantial variation in pricing between each hole. The following items can be quoted on:

• Cost of establishing the equipment on site (kilometers travelled)
• Large diameter drilling from surface to bedrock (per meter)
• Smaller diameter drilling from bedrock to final depth (per meter)
• Symmetrix Drilling (per meter)
• Steel casing (plain or slotted) and installation (per meter)
• PVC casing (plain or slotted) and installation (per meter)
• Development of hole (per hour)
• Gravel pack and installation (per bag)
• Foam injection drilling (per meter)
• Borehole testing
• Pumping and Piping
• Water storage and supply system
• Water quality testing and treatment