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  • Writer's pictureNorhard AS

One day - two breakthroughs

Updated: Apr 26, 2019

Published 28th September 2017

1st breakthrough

Early Tuesday morning on the 26th September little torque was registered from the drill bit at Grytendal. An inspection trip to the intake area showed that the drill bit was in the process of breaking through in perfect position, in the pre-defined pit of the planned intake area.

Drilling of the 555 m long tunnel with a diameter of 0.7 m was thereby completed in just 25 days. A good performance for both equipment and crew.

Thank you to our client NGK for good cooperation and good facilitation during the preparation of the project.

In this project, there was some uncertainty related to geological conditions along parts of the route. During drilling, some areas have been registered for further follow-up. In connection with the drilling equipment being withdrawn, the tunnel video will be inspected so as to obtain the best possible basis for carrying out the next operation. The tunnel will now be reamed to extend the diameter from 0.7 m to 1.5 m. After reaming, depending on the geological conditions, the tunnel may require a full- or partial lining of steel pipes.


2nd breakthrough

Just before midnight, torque was also lost the on the drill bit at the Tenneelva power plant in Vanylven. A breakthrough was confirmed.

Thank you to Tussa Energi who have ensured good facilitation and assistance during the preparations for drilling.

The 0.74 m wide and 400 m long tunnel was drilled with our NDL rig in a record time of just 10 days. A superb performance for both equipment and crew.

Tenneelva breakthrough

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