16-04-2026

Recycling vs ground: a tough battle near Münster

At the IRO show in Oldenburg, our RD1500E still looked fresh from the paint shop. A few weeks later, we spot it along the roadside just outside Münster, running at full capacity and covered in drilling fluid – exactly how we like to see it. On this jobsite of German contractor Heinz Bente, it comes down to one question: how do you get the drilling fluid clean in ground that hardly cooperates? Sand is scarce. Chalk, on the other hand, is everywhere…

A strong team

At arrival we immediately notice not one, but two recycling units in operation. One on the rig side, one on the pipe side. On a narrow jobsite like this, that is no coincidence. Foreman Marcel walks over to greet us. He gets straight to the point. “The ground is challenging here. And that’s not the only thing,” he says. During the Second World War, this area was heavily bombed. After the war, soil investigations were carried out, but not all boreholes were properly sealed. That caused disturbances during the pilot bore.”

Marcel shrugs it off. “My job is solving problems. Has been for twelve years now.” It quickly becomes clear that this crew is used to working together. “We always work with fixed specialists. The team may change slightly, but everyone is experienced.”

Heinz Bente: a family business

The work is carried out under the name of Heinz Bente, a German family business with deep roots in the sector. Now in its third generation, the company is led by brothers Michael and Henning Bente. What started as a local contractor has grown into a civil engineering company with around 120 employees, active across Germany, with an increasing focus on underground infrastructure and energy projects.

On site, that experience translates into a well-thought-out setup. The bore is carried out with a 50-tonne rig from AT-Boretec, surrounded by supporting equipment from the same builder. As a machine builder ourselves, that stands out. it is impressive how the company develops and builds not just the rig itself, but also the supporting equipment. It creates a closed setup where components connect in a logical way.

But on this jobsite, the ground has its own plans.

When the ground refuses to behave

The basics of recycling are clear: shaker screens and hydrocyclones remove coarse material from the drilling fluid. In practice, however, it proves far less straightforward here. “We expected to get more cuttings with a larger reamer, but instead it turns into something like a slurry,” Marcel explains. “Where sand returns as relatively coarse particles that can be separated effectively, chalk breaks down into particles that are simply too fine to separate efficiently.”

Hydrocyclones rely on mass, particle size and centrifugal force. Coarser and heavier particles are pushed outward and separated. With these fine chalk particles, that effect is limited. They remain suspended in the fluid. Despite this complexity, stopping is not an option for the Heinz Bente crew. “The volumes of drilling fluid quickly add up to around 150 cubic metres per day. Over several days, that becomes a significant amount. Disposing of it is simply too costly. And constantly mixing new bentonite would also be a major investment.”

Recycling in stages

Optimisation on this site comes down to working step by step, extracting what can be separated and keeping the rest under control. The RD1500E takes the first pass, removing most of the coarse material. A truck-mounted AT-Boretec filtration system then further reduces the finer particles.

With recycling taking place on both sides of the bore, more coordination and handling are required, but it keeps the process under control. Kevin shows what comes out of the system. “You can still see small lumps of chalk coming through,” he says. “It’s not perfect, but we make it work.” By removing coarse material at an early stage, the load on the second system is reduced significantly. “The 900-litre circulation pump on our own recycling system can handle it better because of that,” Marcel explains. “Without that step, the system would struggle to keep up”

Despite the conditions not being ideal, Marcel is positive about the performance of the RD1500E. “For the volume, this unit is great. The Derrick system works well and it takes out exactly what we need to keep the process running.” Part of that performance comes from the brand-new four-inch hydrocyclones. Compared to larger cones, these are better suited to handle finer fractions.

Modular thinking, LEGO style

“In an ideal situation, you would have a recycling unit that you can adapt to the ground. A kind of modular system, like LEGO,” Marcel says. At the same time, he recognises the limit of that idea. “The next crew still has to be able to work with it. So you’re always looking for a balance.” As a machine builder, that is a familiar tension. Every jobsite is different, and every specialist has their own preferences. Still, the machine has to remain clear and workable for the next crew as well. In HDD, the complexity is already in the work itself.

Mud engineer Kevin Derksen knows exactly what that means. “I’ve been in HDD for two years now,” he says. “What I like about it is that you always have to think. It’s technical, challenging and evolving quickly. And when things don’t go as planned, you solve it together as a team.”

Moving into the next phase

After nearly four weeks, this bore is approaching its final stage, with the 290-metre line being installed for an electricity connection. At the time of our visit, reaming is carried out with a 900 mm conical reamer, before a clean swap to a barrel reamer for the installation of the casing pipes.

Beyond the technical setup, it’s the way this team deals with what comes their way that really defines the job. Practical, inventive and always moving forward with a clear sense of care for the job. Thanks to Marcel and his team for the warm welcome on site and for openly sharing their approach.