Sustainably Safe Transport of Heap Salt Solutions

Durable, corrosion- and abrasion-resistant, and fully monitored – these were the requirements set by LMBV (Lausitzer und Mitteldeutsche Bergbauverwaltungsgesellschaft) for a new 13.5 km brine transport pipeline from Menteroda to the central brine storage basin in Wipperdorf. The egeSmart:Leak Control 3L System with 100% leak monitoring was therefore deployed. Installation using modern and environmentally friendly methods was efficient due to the large drums and required only a few pipe connections.

The Thuringian potash mine Volkenroda was operated from 1909 until the early 1990s. The production residues from potash processing were deposited on the potash residue heap in Menteroda. Due to the total deposited volume of approximately 21 million m³, precipitation causes an average of up to 150,000 m³ of highly mineralized heap seepage water annually.

LMBV mbH, as the legal successor of the former potash mine, is responsible for the closure of the mine, the prevention of hazards to the public, and the permanent securing of the surface facilities.

Since the mid-1990s, these waters have been discharged into the mine via the then still open Volkenroda shaft and later via flooding boreholes. After the complete flooding, the so-called wet closure of the Volkenroda/Pöthen mine workings, the heap waters are to be transported to the central brine storage basin in Wipperdorf and discharged there in a controlled manner into the receiving water in accordance with the permit.

For this purpose, LMBV had a 13.5 km pipeline constructed from the storage basin in Menteroda to the connection point with the existing heap water pipeline in Sollstedt. For the discharge of the saline waters, the following high requirements were placed on the newly constructed pipeline during the planning phase:

durable
corrosion-resistant
abrasion-resistant

To additionally meet the high environmental protection standards, the pipeline was to be permanently and completely monitored during operation in order to detect even minor damage before an actual pipe rupture occurs. Based on the above requirements, the egeSmart:Leak Control 3L System was selected. The basis of the pipe system is a core pipe made of PE 100-RC, which is laminated with a diffusion-tight and electrically conductive aluminum layer that immediately reports even the smallest damage. An additional extruded protective sheath made of modified PE provides electrical insulation from the ground.

The required fittings such as bends, reducers, connection pieces, and tees were manufactured individually in the fittings production facility at egeplast in accordance with the requirements for the egeSmart:Leak Control 3L. Approximately 8.6 km of OD 180 mm dimension were used, which could be delivered on large drums of 500 m each. The 5 km of the larger OD 200 mm dimension that were also required were delivered as 20 m length pipes. The installation of the 3L Leak Control pipeline was carried out using open trench installation, the milling method, and in 10 separate directional drilling operations. The necessary connections of the pipes and fittings were made according to DVS 2207 using butt fusion and electrofusion welding.

The controlled horizontal drilling operations were carried out by BLK Bohrteam GmbH from Mertendorf. The pipe installation using the milling method and open trench installation was performed by ARGE Hoch- und Tiefbau Ebeleben GmbH from Ebeleben together with HELMER Rohrleitungsbau from Apfelstädt.

In order to immediately receive a corresponding notification in the event of damage to the pipe system during operation and to narrow down the damage location as precisely as possible, LMBV divided the electrical monitoring into 15 separate measuring circuits, which are centrally combined in a monitoring unit. In the event of damage, an error signal is automatically triggered in the affected measuring circuit, so that in an acute case the pipe sector to be inspected is precisely defined and the fault can be located quickly and accurately.

The operational capability of the monitoring for each individual measuring circuit was measured by specialists from egeplast and handed over to the client in working condition. After construction began in 2019, the construction project was completed in 2021. The construction costs of the project amount to approximately €14 million, which were financed by the Federal Government of Germany and the Free State of Thuringia.