The Swiss contractor Jablo Tiefbau AG from Murgenthal has used the TERRA MINI-JET MJ 1600 to drill a new sewer line, which connects the “technic building” of the road tunnel Schönthal with the external sewer manhole. The Schönthal tunnel is a main part of the national road Liestal-Pratteln. The installation of the HDD machine happened directly besides the tunnel entry. The power pack and the mixing station were installed outside of the building. The drill rig was carried into the building and lifted into the starting pit with two chain hoists. The drill target was the 10 m (3.3 ft) deep sewer manhole with a diameter of 800 mm (32”). It should be hit in its middle in a depth of 5 m (16.5 ft). The manhole allowed to pull in screwable short HDPE pipes OD 180 mm (7.1”).
The hydraulic pack, the mixing station and the drilling fluid tank were installed at the tunnel entry.
A core hole drill Ø 250 mm (10“) was drilled through a concrete wall before the MINI-JET drill rig was installed.
The hydraulic hoses were laid through the building. They connect the power pack with the drill rig.
The drill rig TERRA MINI-JET MJ 1600 is installed. The sonde housing starts the bore.
The drill rig is lifted into the drilling position with two chain hoists.
The working platform with stairs was installed besides the top of the sewer manhole. The 800 mm (32”) manhole is approximately 10 m (33 ft) deep.
The monitor (display) shows all relevant data. The locator (receiver) stands at the right side.
The contractor Serge Jakob sets lots of value on safety. He is equipped with helmet, gas alarm unit and climbing harness.
After the pilot bore was finished, a temporary wooden floor was built into the manhole.
The first short pipe is pulled with an expander chuck. All other short pipes are screwed in the manhole.
The new pipe has been pulled in completely. Then the core drill is filled with concrete.