Climate change and the particularly long periods of high temperatures last summer had a severe impact on the Rhine, meaning that supplies to companies along the river could only take place under difficult conditions and with restrictions. Shipping and the associated transport of goods have suffered enormously. For one of the most frequented goods transport routes, it is therefore particularly important to keep the channel navigable, to improve it, to prevent water levels falling and to secure the infrastructure for the future.

The task

Milling work must be carried out in the Middle Rhine area, between Östrich and Geisenrücken, in order to guarantee a target depth of 2.10m below GIW (equivalent water level). For this profiling of the channel, obstacles (such as crags) are removed underwater at specific points. The scaly, cracked material with a hardness of up to 100MPA requires suitable drum cutter sizes and carriers. The project – funded by the Federal Ministry of Digital Affairs and Transport – proved to be challenging for all parties involved because the use of hydraulic breakers or blasting is not permitted due to harmful vibrations and uncontrolled sediment formation. Special conditions for working underwater also apply, not least nature conservation requirements.

First class and sustainable

The Wesel based company Hülskens Wasserbau GmbH & Co. KG, used two floating pontoons for the project, on which the required technology is permanently installed. A Demag-H95 special excavator mounted on the front pontoon serves as the carrier. The usual tests for armaments were carried out beforehand, with none being found, although large amounts of scrap were uncovered, with conditions onsite enabling work to proceed.

The necessary work in sensitive conditions proved to be the ideal task for Epiroc’s ER 3000 drum cutter equipped with special additional features. It not only has special wear protection for extreme underwater use, but also an additional suction hood installed in the first construction phase which encloses the drum cutter over a large area. With this tried and tested technique, the excavation material produced during the milling work is extracted and transported to the rear pontoon in a controlled manner. A technically sophisticated filter and separation system, as well as a loading container for the excavation material, were also used. As the underwater work requires environmentally safe operation, it proved fortuitous that the Epiroc drum cutter is not only powered by bio hydraulic oil, but that a special bio oil is also used as the gearbox lubricant. During operation, the ER 3000 is supplied with an oil quantity of 420l/min.

All in all, the work has so far been carried out without any difficulties or damage. The low wear on the cutting tools once again underlines the high quality of the ER 3000 (Epiroc states  that this has been to the delight of everyone involved). Erkat’s milling technology, which has been part of the Epiroc Group since 2017, was said by the company to demonstrate the ideal combination of material, procedure and know how.