TERRA AG
Terra AG was founded in 1975 by Dr. Ing. Gustav Jenne. Today his son Dipl. Wirtschafts-Ing. Dietmar Jenne is the president of the company. He studied at the Technical University Karlsruhe mechanical engineering and management. They have many important industry engineering patents. CJ Kelly Associates exclusively represent the interests of Terra for its complete product range across the whole of the UK. We distribute Terra AG’s range of HDD rigs, Mini HDD rigs, Hydraulic Pipebursting systems and Impact Hammers for new pipe installation, pipe ramming and pneumatic bursting operations and cable-based pipe pulling systems for pipe replacement works.
TERRA HDD
The Terra range of HDD rigs and Mini HDD rigs covers thrust and pullback capacities from 8 t to 23 t over four models including the TERRA-JET 4015 S.The extensive 2.5 year development project succeeds in integrating man and machine to create a truly superlative Directional Drill. Operator comfort and ease of operation is facilitated within a technically advanced HDD machine; the result is pleasing aesthetics, revolutionary operating concepts and enhanced machine capability and productivity. The TERRA-JET 4015 S is the first HDD model in the new S-Series.
The TERRA-JET 4015 S may drill directional bores up to 200 m length and 460 mm diameter (depending on ground conditions). It is driven by a 62.5 kW (85 HP) powered diesel engine, which is “clean” and fulfils the required “green” emission regulations for some years to come. Torque and pullback force are produced by separated hydraulic circuits allowing the maximum torque of 4’000 Nm and the maximum pullback force of 150 kN (15 tons) to be used simultaneously under full load. A rarity nowadays in HDD machines!
The pullback force is produced by a robust hydraulic cylinder. In comparison to hydraulic motors and rack-and-pinion drives of conventional HDD machines, the hydraulic cylinder shows its superiority in hard ground which requires slow backreaming speeds. Here the hydraulic cylinder has its highest efficiency rate whilst hydraulic motors lose up to 25 % of their power at the low rotation speeds required in these hard grounds.
The drilling fluid volume is 90 ltr/min at a maximum fluid pressure of 70 bars. The drilling fluid volume may be optionally increased. The mixing system which mixes the Bentonite into the drilling fluid via an injector (venture hopper) is on board the HDD machine. This patent removes the need for an extra mixing system and a second engine.
The S-Series is designed to be extremely service friendly and reliable. All hydraulic components are easily accessible for servicing. The engine cover is made of glass fibre reinforced plastic (GRP) and can be lifted up to 45°, supported by gas-filled struts. They can also be lifted off completely allowing the best access to all components. The electric components are assembled in the central control panel inside of the cabin with easy access.
The TERRA-JET 4015 S is compact and manoeuvrable in spite of its high power output and superior operating capabilities. It is only 2.1 m wide and 5.8 m long which allows operation in confined city spaces. It can be easily transported with an operational weight of 6.7 tons.


- Pulling Force: 15 Tonne
- Torque:4,000Nm
- Drilling Fluid Volume: 90 L/min
- Drilling Fluid Pressure: 70 bar
- Drilling Length: 200m
- Backream-∅:460m
- Drill Rods: 3m
TERRA-HYDROCRACK
For pipe bursting the company offers the TERRA-HYDROCRACK unit which is available in both standard and ‘Comfort’ versions with 60 t pullback capacity for pipe replacement up to 350 mm diameter over up to 150 m lengths. The TERRA-HYDROCRACK is a hydraulic cracking system to renew gas pipes, water pipes or sewerage lines. Due to its high thrust and pullback forces of 600 kN (60 tons) it cracks or cuts PE pipes, steel pipes, cast iron pipes or even ductile cast iron pipes from ø 50 mm to up to 350 mm. New HDPE pipes up to OD 355 mm may be pulled in. In a first step, the highly sophisticated rods are pushed through the old pipe. As soon as the rods arrive at the target pit, a 3-wing bursting rod, an expander cone and the new PE pipe are assembled to the rod. Now the TERRA-HYDROCRACK pulls the rods back, cuts the old pipe into 3 slices, enlarges the bore channel and pulls in the new PE pipe – all simultaneously. It is even possible to push the rods into a second pipe section, whilst the new pipe is pulled in into the first pipe section. This saves time.
The main cylinder with hollow piston rod can be moved inside of the trench box from the front to the rear. This allows to pull the bursting tools and the new HDPE pipe completely into TERRA-HYDROCRACK after the pull-back operation. Therefore it is not necessary to move the whole machine. It is possible to work in both directions of the working pit without turning the machine. Whilst the HDPE pipe is pulled into the first section, the rods may be pushed simultaneously into the second old pipe section.
TERRA-HAMMER
In the Impact hammer range there are some 25 models ranging in diameter from 45 mm to 565 mm in a variety of standard and short lengths for easier access to limited space situations. In the range from 800 mm diameter upwards the hammers may also be used for pneumatic steel pipe ramming operations. Pneumatic pipe bursting can also be achieved with certain models. The exclusive combi head in combination with the heavy main piston guarantees unequalled penetration speed and accuracy. Aerodynamic air flow patterns ensure low air consumption and minimal recoil. The main piston hits inside the head where it is most effective and not behind it.
In Version SK the end cap is locked in place allowing servicing on the jobsite within a few minutes. The TERRA-HAMMER is unique in design and operation which assures years of dependability. It comprises some 40 % less parts than comparable piercing tools.
Quick Reverse is enabled by a simple ¼ turn of the air hose. No unintentional reversal of the tool during operation due to pneumatic locking (Version S). Larger tools are equipped with a remote controlled reverse (Version F).

TERRA-EXTRACTOR
The TERRA-EXTRACTOR systems are designed to replace old pipe by passing a cable through the pipe and utilising the powerful pulling unit to either cut the old pipe in situ and using an expansion shell to open up the void into which the new pipe is towed or to fully remove the pipe by pulling it out of the ground, whilst pulling the new pipe in behind the extraction cable. TERRA-EXTRACTOR is available in three models: TERRA-EXTRACTOR X 100; TERRA-EXTRACTOR X 300; and TERRA-EXTRACTOR X 40

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