Trenchless Technology HDD drilling machines and piercing tools


HDD class: 20 - 25 tons

		Spülbohrung mit dem TERRA-JET 8522 S

Horizontal directional drilling with the TJ 8522 S

  1. with comfortable wide driver’s cab
  2. good view around, the cab has large windows all around
  3. the operators seat can be turned by 180°
  4. drill rod changer with 120 m (400 ft) of drill rods
  5. on-board computer with touch screen for digital display, control, documentation and diagnostics
  6. automatic greasing for each drill rod thread
  7. automatic release of drilling fluid pressure before each rod change
  8. computer recording of each bore (forces, torque, fluid volume and pressure according DVGW 321
  9. optional without driver’s cabin and without board computer
  10. for drilling lengths up to 400 m (1300 ft) and bore channels up to Ø 1’000 mm (40”) (depending on ground conditions)
  11. 25 % better efficiency rate due to new intelligent hydraulic system with four independent hydraulic circuits
  12. "all on board", including the complete mixing system (without tank)
  13. any tank (2’000 - 10’000 ltr, 500 – 2’500 gal) can be used
  14. shortest installations time, the bore can start after a few minutes
  15. high productivity through the automatic drill rod changer
  16. standard equipped with ADBS (Automatic Drilling and Backreaming System), pat.
  17. all main functions are operated via 2 multifunctional joysticks
  18. THRUST and ROTATION are driven by separated circuits. Both functions are driven proportionally
  19. maximum thrust and pullback forces even at low pullback speeds (thrust and pullback forces are produced by a hydraulic cylinder!)
  20. Rock drilling possible with TERRA-ROCK Drilling Tools
  21. Currency: 24 Volts
  22. the rubber crawler protects the surfaces
  23. Environmentally friendly. The Diesel engine fulfils today’s Emissions Limits in Europe (EURO 3 A), USA (TIER 3) and Japan.

Service friendly

    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 Drivers' Cabine

    The Premium model of the TERRA-JET 8522 S is equipped with a comfortable driver’s cabin, which sets new standards. The cabin has all round tinted glazing, with the machine side being glazed in a single uninterrupted panel. This allows the operator to see every detail of the drilling machine. Large windscreen wipers with jets clean the front and right panels. Additionally the drilling fluid pressure inside the drill rods is automatically released just before each drill rod change, preventing bentonite from being splashed onto the glazing.

    The operator sits in a comfortable operator’s seat, which can be adjusted to suite the body shape and weight of the operator. The operator’s cab is wide allowing the seat to rotate 180°. The drill operator can drill looking in the drilling direction, or he can rotate the seat to be at right angles to the drill and observe every detail of the drilling machine.

The Drivers' Cabine
The Drivers' Cabine

Ergonomic operator's station

    The drill operator drives and operates the HDD machine using the two multifunctional joysticks installed in the left and right armrests of the operator’s seat. Driving using the joysticks allows instantaneous control and smooth movement of the TERRA-JET.

    A large touch screen with on-board computer is installed in the driver’s cabin. The monitor displays all vital information needed at any instance, and is controlled by finger touch on the screen.

    The on-board computer updates and saves all relevant machine data every two seconds updating the operator on the essential drilling elements. This data may be transferred to a laptop for later evaluation and provides essential data for efficient service diagnostics. Additionally a bore log can be printed for each bore as regulated in the German specification DVGW 321. The bore log shows the torque, the drilling forces, the drilling fluid volume and pressure for each metre of the pilot bore and backreaming undertaken.

Ergonomic operator's station
Ergonomic operator's station


    The TERRA-JET 8522 S is equipped with an electronic Automatic Drilling and Backreaming System (ADBSe).
    This patented system automatically and within milliseconds adjusts the working speed of the drill to suite the ground conditions. In soft ground the drill operates at maximum speed, in hard ground slowly, but always at the optimum speed.

    This allows the operator to operate the drill at maximum efficiency in a controlled and relaxed manner and prevents the drill rods and drilling tools from being overloaded. During the pilot bore the ADBSe controls the thrust force. If the drill head hits an unexpected obstacle, the ADBS stops the drilling speed immediately and drills very slowly through the obstacle. All automatically!


Technical Data

Technical Data

*   Depending on ground conditions
** Depending on drill rod size
Technical specifications can be changed without previous notice.
Pullback force
220 kN (22 to)
48’400 lbs
Thrust force
110 kN (11 to)
24’200 lbs
Engine power
Perkins 97 kW (132 PS)
Perkins 97 kW (132 HP)
Torque, 1st speed
8’500 Nm
6’250 ft.lbs
Torque, 2nd speed
4’250 Nm
3’125 ft.lbs
Drill rod rotation speed, 2nd speed
123 U/min
123 rpm
Drill rod rotation speed, 1st speed
58 U/min
58 rpm
Drilling fluid volume - Pilot bore
122 ltr/min @ 60 bar
32 gpm@ 870 psi
Drilling fluid - Backreaming
400 ltr/min @ 19 bar
105 gpm @ 300 psi
drilling speed - quick gear
35 m/min
115 ft/min
drilling speed - at full load
15 m/min
50 ft/min
pullback speed - quick gear
17 m/min
56 ft/min
pullback speed - at full load
7 m/min
23 ft/min
Guaranteed sound power level Lwa
103 dB(A)
103 dB(A
noise emission at operator’s ear - with cabin
68 dB(A)
70 dB(A)
noise emission at operator’s ear - without cabin
83 dB(A)
85 dB(A)
Ø of the pilot bore
90 – 170 mm
3.5” – 6.7”
Maximum backream diameter*
Ø 1’000 mm
ø 40”
Maximum drilling length*
400 m
1300 ft
Drill rods, length
3.0 m
10 ft
Drill rod, diameter
70 mm
Minimum turning radius **
45 m
115 ft
Dimensions L x W x H with cabin
6.40 x 2.25 x 2.55 m
21.1 x 7.4 x 8.4 ft
weight with cabin incl. 40 drill rods, ø 70 mm
9 to
19’800 lbs


TERRA AG für Tiefbautechnik - Hauptstrasse 92 - 6260 Reiden - Schweiz - Tel. +41 62 749 10 10 -