are generally drilled when ground water is not accessible by means of a wellpoint.
A borehole is drilled to a required depth and water level which will be continuously monitored during the drilling process.
The ground structure that is found during the drilling process will determine whether the driller will continue mud drilling or move over to air drilling.
Types of borehole drilling
1. Mud rotary drilling
Mud drilling is a mixture of clay, water and chemicals that is pumped down a drilling stream while cutting a hole in a very soft sand formation, that will allow the sand formation to bind and stay open so that on completion of the drilling, a casing can be installed, that is perforated and screened.
The pvc borehole casing can be installed om completion of drilling and that the hole can be gravel packed to allow for maximum water filtration.
Mud drilling is also used in clay formations.
2. Air or pneumatic percussion drilling
Air rotary drilling is a method used to drill boreholes in rock formations.
The drill bits “cuts’ the formation into small pieces, called cuttings.
This method utilizes air as a circulating medium to cool the drill bit, bring drill cuttings to the surface, and maintain borehole integrity.
Mechanical fracturing of rock is still the most effective means of advancing the drill head, thus in the proposed ideal smart drilling approach, the drill must sense the type of rock or stratum ahead of the drill bit, recognize its resistance, automatically adjust the drilling process in terms of rate and contact pressure.
3. Monitoring boreholes
We also do the installation of monitoring boreholes.
Monitoring boreholes project was completed at the Atlantis landfall site, Western Cape.
Surface emission monitoring is a technique that involves using a portable methane meter near the landfill’s surface to measure concentrations while traversing the site