The 'in-hole' Philosophy of PAT

PAT's reputation is built on its range of drilling machines characterised by being small & lightweight. How is it possible to achieve so much with equipment so small?

The ability to construct groundwater supplies reliably, quickly at an enviable construction costs means close understanding of the drilling process and how this relates to water well construction.

Broadly these are summarised as follows.

Drill a hole at diameter suitable, just for the volume and method of the pump. Normally nominal 4" finished hole will meet a huge requirement for water whether hand or machine pumped.

Use the best quality - strongest and highest in-flow capacity well liming materials.

Where appropriate drill unlined. Hard consolidated rocks that need tough drilling tools to find water in fissures and cracks do not need lining with screen - this restricts well production and increase drilling costs.

By drilling at the minimum accepted diameter has a big impact on the equipment used.

The hole diameter relates to the hole area - a 6" diameter hole is more than twice the area of a 4" hole - to excavate twice the volume of spoil has to be removed at twice the weight.

To the drilling process this means the tools that effectively excavate the hole - the mud pumps or compressors have to develop sufficient flow to allow the material to be washed or blown up a borehole to the surface (annular space between borehole walls and drill pipe) at a fast enough speed to allow the process to work (up hole velocity).

Again a 6" hole will require a pump or compressor twice the volumetric capacity than a 4" hole.