Cable percussion also known as shell and auger drilling, is the most commonly used technique for drilling and sampling soils where good quality undisturbed samples are required.
The equipment is suitable for drilling in all types of soils and weak rocks. In the hands of our competent and experienced drillers the equipment provides a rapid and cost-effective method of investigation to depths of up to 60 metres.
The rigs are driven by diesel engines and when erected require a working headroom of approximately 6 metres and a working area of approximately 3 metres by 8 metres. The tripod folds down to form a simple trailer that is towed by a four-wheel drive vehicle, meaning that most positions with reasonable level and clear access can be reached.
The drilling technique allows the installation of casing inside the boreholes to prevent loose soils collapsing into the hole, allowing the borehole to be advanced to considerable depths, whilst maintaining good progress. The borehole is cased as required to maintain stability and also to prevent ground water inflows and undisturbed samples and Standard Penetration Tests (SPT’s) can be carried out in the boreholes. On completion, gas or ground water monitoring standpipes can be installed in the borehole.
Boreholes can be drilled at a variety of diameters including 6 inch, 8 inch, 10 inch and 12 inch casing.
As the drilling method is percussive there is some noise during drilling both from the diesel winch and from the driving of casings. Using this method is relatively tidy and spoil and water can be readily contained within the working area. On completion of the borehole it is back filled and the surfacing reinstated, leaving little or no disturbance to the working area.
The cable percussion rig can be moved into difficult positions or onto an over water drilling platform by means of a crane.
Borehole log sheets can be emailed or posted to clients within a couple of days of the drilling works being carried out or the following day if the job is local.
Specifications for the type of rigs we have are as below.