Throwback: Kijfhoek 2006, the HDD crossing that put Brownline on the map

The Drillguide Gyro Steering Tool was developed in the years before 2006. This system was supposed to answer the question: how can you take measurements underground independently of the environment?

Bertjan Molenaar: “We had our own magnetic steering tool, but wherever there is magnetism, a tool like that fails. So we developed the gyro because we really believed that this could be done.”

Drilling under 62 railway tracks was and still is an extreme example of magnetic interference. The tracks also created a long blind section in the 700 m (2300 ft) long crossing, leaving no possibility to monitor the drill from the surface. An HDD crossing like this had never been done before.

Bertjan: “After a number of test drills, Kijfhoek was the first real crossing where you had to rely entirely on the gyro. Our client, Van Leeuwen Sleufloze Technieken, said: ‘Either we cannot carry out the job, or what you say is true and then it can be done after all. We will take on this job because we believe you.’ And so we had a client who was up for the challenge, but we still had to prove it.”

The drilling took a little over than a week and Bertjan surveyed about 80% of the job. In the last few days, work continued in day and night shifts, with Hans de Bruin taking on the night shift. The first version of the Drillguide GST was used to survey the progress of the drill. Because the Smart Guide software currently used by Brownline did not exist back then, Bertjan had to do the calculations himself.

Bertjan: “The tool provided inclination and azimuth, and you had to do the rest yourself. Because you had to do your own calculations and keep track of everything, it was much easier to make mistakes back then. Nowadays, a lot more is automated in the software, but the principle has remained the same. The key is getting the correct angles.”

After drilling 700 m (2300 ft), including a horizontal curve, the drill head surfaced on the other side of the marshalling yard, just 30 cm (1 ft) from the exit stake.

Bertjan: “I have never seen people so happy as when this drill punched out. Now we are all accustomed to it, but back then, at the moment the drill went into the ground, we didn’t know for sure that it would actually come out right on the other side. That was super exciting for everyone.”

Bertjan: “Everyone in the HDD industry who sees a photo of this job says, ‘That's impossible.’ They immediately see the problems, especially back then. Nowadays we no longer think in terms of magnetism, but back then everyone did, because that was the standard. With an overview photo of the marshalling yard, we were able to show that this wasn't possible back then, and since then it is possible. That, I think, is the power of this crossing.”

“After this project, things changed, and for Brownline too. It worked perfectly as promotional material because you don't have to explain anything. 62 railway tracks, that's all you need to say. Everyone in HDD knows what that implies. Certainly back then, now we've become used to it. Now we would still find it an interesting job, but back then it was impossible.”

“This project did a lot for Brownline. We were able to demonstrate our proof of concept with this. We used the success of this project to increase our business with our first three clients in the Netherlands. Then we gained more Dutch clients, soon followed by clients in Belgium, and later in Germany.”

Bertjan: “For me personally, this is the most special crossing we have ever done. This was a game changer. In hindsight, we have done more spectacular jobs – Texel was larger in terms of length – but Kijfhoek had a greater impact. This was the most exciting one. Personally, I'm most proud of this one.”

Brownline looks back with great pride on the Kijfhoek HDD crossing, on the impact the project has had, and on the development we have experienced over the past twenty years.