Steerable GRUNDOPIT mini drill rigs are used for the trenchless construction of house connections for gas, water, power, FTTH and sewage pressure lines along complicated bore paths using HDD, e.g. within existing infrastructures, in confined spaces, demanding terrain such as slopes and/or difficult soils.

In addition to house connections, parallel bores of up to 100 m length und short undercrossings are also possible with thesemini horizontal directional drilling machines Depending on the soil, a water-polymer drilling fluid or a bentonite drilling fluid is used. Depending on the type of drilling, pipe diameter, soil type, bore length and degree of difficulty, HDD bores with the small drill can be launched out of a pit or a circular keyhole.
 
In the minimally invasive keyhole method with the GRUNDOPIT KS50 horizontal directional drilling machine house connections are installed out of the smallest possible round construction pit (keyhole Ø 65 cm) from the main pipe directly into the house or into a small construction pit in front of the house. All connection work is carried out above ground and the keyhole is then restored with the removed drill core without additional asphalt work or consequential damage.