HDD Success in Poland

In the Polish city of Kielce, a 76-m long HDPE pipe OD 160 mm had to be laid to the exhibition area. This pipe laying job had to been done using trenchless technology because the exhibition entrance had to be crossed and not disturbed.

Contractor Ekobox Sp. z.o.o. was responsible for this project. Based in Kielce, Ekobox employs approximately 100 workers and specializes in installations for telecom, power lines and road lighting. Ekobox is also a specialist for trenchless pipe and cable laying and for many years has worked with piercing tools. Recently, Ekobox added to its equipment fleet the horizontal directional drilling machine TERRA-JET 4015 S, which was used on this particular project.

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Mr. Suchansky, owner of Ekobox, decided to obtain the premium model of the TJ 4015 S, which is equipped with a driver’s cabin that has air conditioning and an MP3 player, as well as an on-board computer with a touch screen. Capabilities of the on-board computer include being able to save information about every meter of the bore. This function allows Ekobox to print out a bore protocol with all torques, pulling and thrust forces, as well as the drilling fluid volume and drilling fluid pressures. The touch screen gives all the information that the operator requires.

The operator’s cab is wide enough to allow the seat to rotate 180 degrees. The drill operator can enter the cabin with ease, rotating the seat toward the door. He can drill looking at the direction of the borepath or he can rotate the seat to be at right angles to the drill and observe every detail of the drilling machine.

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The drill operator drives and operates the HDD machine using the two multi-functional joysticks installed in the left and right armrests of the operator’s seat. Using the joysticks while driving allows instantaneous control and smooth movement of the drill.

The TERRA-JET 4015 S may drill directional bores up to 200 m in length and 460 mm in diameter. It is driven by a 62.5 kW-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 3,000 ft-lbs and the maximum pullback force of 15 tons, (33,000 lbs) to be used simultaneously under full load.

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The drilling fluid volume is 90 l/min at a maximum fluid pressure of 70 bars. The drilling fluid volume may be increased. The mixing system mixes the bentonite into the drilling fluid via an injector that is on board the HDD machine, removing the need for an extra mixing system and a second engine.

The TERRA-JET 4015 S is equipped with a second generation Automatic Drilling and Backreaming System (ADBS). This patented ADBS automatically and within milliseconds adjusts the working speed of the drill to suit the ground conditions.

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The project for Ekobox went smoothly and the drill crew did not experience any problems drilling the 76-m long pilot bore in the sandy clay. The drill head could even be located underneath the reinforced concrete plates.

After the pilot bore was completed, the drill head was replaced by a new back reamer, 215 mm. TERRA AG developed this new type of backreamer with tungsten carbide teeth, which can be replaced easily as needed. This backreamer has an integrated protection pipe for the swivel that closes the space between the backreamer and the HDPE pipe so stones cannot fall in front of the expander chuck and block the backreaming.

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With the backreamer, the 160-mm OD HDPE pipe was pulled in simultaneously. This was also not a problem for the Ekobox crew and project was successful completed, according to the contractor.

This article was submitted by TERRA-AG, which is headquartered in Reiden, Switzerland.

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