Suction Dredger Elerweerd, Steengoed, Belgium

The 170-hectare "Elerweerd" project is located on the border between Dilsen-Stokkem and Maaseik. Since 2019, approximately 1.5 million tons of gravel and fill sand have been extracted here annually. It is operated by an initiative of Steengoed Projecten, Regional Landscape Kempen, and Maasland. In addition to extracting raw materials, the project aims to increase river safety during periods of high flow in the Meuse and to create unique natural values.

"With the new dredger, we will primarily extract sand from this already "processed" lake and then transport it to another location for refilling. Since this is an internal material transport, efficiency (i.e., high extraction rates at low operating costs) is extremely important," says David Musiek, Managing Director of belmagri, one of the partner companies in the operating consortium.

Dredger 2.0

"We are a leader in Europe with this technology. The ability to move the dredger freely, essentially "unmanned," across the lake surface using GPS, while taking the individual terrain model of the subsurface into account, sets new standards in efficient raw material extraction through dredger," explains Emad Zoghi, Managing Director of WorldDredgers GmbH & Co. KG since 2022. "In addition to the customer-specific planning of a new extraction device, as well as construction and on-site installation from a single source, the main focus was on increasing automated efficiency for specific subsurface conditions," Zoghi continues. As a mechanical engineer and project manager, Zoghi brings international experience. Since then, he and his team have invested a lot of time and expertise in the development of digital systems. "Decentralized access to the control system of a suction excavator, even in real time, is almost normal. In the past, a technician always had to travel there and check everything on site. But long journeys mean downtime, and that costs time and money. For a long time now, we have been logging into our customers' extraction equipment in Germany, France, or Scandinavia using a laptop, for example from Wesel. We see what the excavator operator sees, sometimes even a little more when we analyze the "technology behind it." Even if a suction excavator doesn't look like Industry 4.0 from the outside, it contains a wealth of complex process control, designed primarily for efficiency in terms of energy consumption and optimal production output. In addition to the suction power, excavation depth, GPS-controlled positioning and movement, the entire control system of the modern electric motors, the downstream conveyor belts, and intermediate boosters are digitally linked. If even just one parameter is not set quite correctly, a message appears. Sometimes, however, it's just small things in the system, in the settings, that need to be changed, or the electronic control system needs a quick tweak to get everything running optimally again. This might take just a few minutes or a few hours. Using digital remote maintenance, we can quickly find and fix software errors or intervene directly in the event of malfunctions or downtime. The step to autonomous motion control was simply the logical consequence."

Material conservation and flexibility in personnel deployment

After extensive preparatory work for the planned dredger in Elerweerd, the autonomous motion control technology was first installed and tested in practice on an existing suction dredger in Ophoven, North Rhine-Westphalia, in spring 2024. "This has given us significant progress and provided additional support for the final system for Elerweerd," says Zoghi. The basis is a specially programmed, GPS-based process control system that enables the suction dredger to change its position on the lake independently and fully automatically, without active intervention from the dredger operator. A 3D terrain model of the subsoil is continuously created as a basis, to which the dredger and pump controls respond. In addition to the position, the suction power and corresponding parameters are automatically adjusted to the material deposits and the soil structure on the lake bed. Zoghi: "This allows the extraction device, for example, to work a previously defined lake area, or rather, a structure on the lake bed, 'all on its own.'" The entire process is visualized in parallel on a monitor or documented upon request.”

Even in the event of material collapse, foreign objects, or "clay," the system independently detects the situation and reacts automatically. This reduces downtime and extends the service life of all components. In addition to greater efficiency and material conservation during raw material extraction, it also opens up additional opportunities for cross-deployment of personnel. The excavator operator could simultaneously monitor production, the bucket wheel, or the loading of trucks, which is another advantage in times of skilled labor shortages. Essentially, this would allow the excavator to operate independently at night, thus optimizing material extraction. This is also a worthwhile subsequent investment for subsequent gravel extraction with suction dredgers, as previously excavated subsoils can be systematically vacuumed again according to a predefined GPS grid.

Theory and practice from a single source

To further optimize the system's performance while simultaneously reducing maintenance and spare parts costs, identical pump systems were installed for the first time on the dredger and the two downstream boosters of the 3.7 km long production line. As part of the Hülskens group of companies, World Dredgers benefits from synergies and cooperation with other company divisions, such as Hülskens Industrial Services, including the design department, steel and engine construction, and its own electrical and programming department. This is also complemented by many years of experience in gravel and sand extraction and the associated requirements and challenges for such systems.

David Musiek: "It was important to us to get a functioning system from a single source, from planning to the operational equipment. This obviously involves technical details and costs, but also knowing what such a system has to do in practice on a daily basis. Furthermore, our requirement when awarding the contract in autumn 2023 was that the excavator could be operational by the end of 2024 at the latest. Both of these criteria worked out very well."