I found a company that does various types of drilling that I thought might be of interest.
They have developed a slightly different method of drilling for geothermal heat pump that could be used by some here. Also they did some tests that showed that a coaxial heat exchanger pipe in the ground would be more efficient and easier to install than the u-pipe currently being used. I will include some web sites to explore. Also there are some videos that explain very well.
The innovative GRD system - TRACTO-TECHNIK GmbH & Co. KG
TRACTO-TECHNIK - The only choice for perfect pipe installations - TRACTO-TECHNIK GmbH & Co. KG
Tracto-Technik TV
http://www.tracto-technik.de/doks/pd...gleich_EN1.pdf
Hope these work. Charlesfl