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Accurate and benign drilling in dams

Water dam sine in the distance in the sunset

Wassaras water-powered drill hammer has been widely used in dams all over the world. It's benign, accurate drilling and high penetration rate has been proven over and over again.

Dam drilling

When rehabilitating a seeping dam, there is a need of drilling many deep boreholes for installation of concrete walls/grout curtains of different designs. It is in this kind of applications the Wassara technology has proven its superiority.

There is always a concern when drilling in dam structures; factors like minimal borehole deviation and no pressuring of the formation are crucial. With Wassara you get this, together with an outstanding borehole accuracy and cleanness with very little impact on the formation.

Suitable for most dam drilling applications

Reduction and control of water seepage is the key factor in dam management. The Wassara technology has several benefits regarding both different dam rehabilitation methods and construction of new dams:

1. Drilling to repair existing drainage- and service tunnels by injection of grout

The greatest advantage of drilling with a water-powered DTH hammer is the possibility to drill deep, straight holes with a minimum of deviations.

When drilling in existing dams, you often face a tight clearance that demands very low borehole deviation. Wassara has proven capable of drilling with very low deviation.

2. Drilling for installation of grout curtains and concrete walls in order to minimize leakage

Another advantage with the Wassara drilling technology is the minimal risk of pressurizing the surrounding formation, which ensures a minimum of disturbance to the surrounding formation.

3. Drilling grout holes for new dams

The body of the dam may be made of extremely hard concrete, while the formation beneath the dam may be a very soft volcanic and sedimentary rock type.

The water-powered drilling technology is known to be capable of handling this kind of challenge.


Example of successful projects:

A narrow corridor inside the dam where a small drillrig is drilling with Wassara’s water powered hammer

Drilling in confined galleries in Angostura dam

The bedrock needed water-proofing, this was done by drilling 64 mm holes and then grouting with cement. The Wassara system was also used for drainage drilling with 102 mm diameter holes. The allowed borehole deviation was set to 2% at full length. Wassara managed to meet the requirement by far. The drilling environment was healthy, friendly and comfortable as it was dust-free and held a low noise level.

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A small white drill rig standing on a concrete ground outdoors, ready to drill in to a water dam body with Wassaras water powered hammer

Rehabilitation of the very sensitive Wolf Creek Dam

Wassara's waterpowered drilling equipment was chosen for the drilling of both the Ø 95 mm (4") boreholes for grouting as well as the Ø 200 mm (8") pilot holes.

The water-powered technology proved to be both accurate and benign to the formation. Max allowed borehole deviation for the project was 0.15%. Wassara both met the stringent requirements and kept the time schedule.

Read the full version here!