Sustainable and Secure Transport of Spoil Heap Brine Solutions

Durable, corrosion and abrasion-resistant, and fully monitored – these were the requirements of LMBV (Lausitzer und Mitteldeutsche Bergbauverwaltungsgesellschaft) for a new 13.5 km long brine transport pipeline from Menteroda to the central brine stacking basin near Wipperdorf. The egeplast 3L Leak Control System with 100% leak monitoring was therefore used. The Installation in modern and environmentally friendly processes was effective due to the large drums and required only a few pipe connections.

The Thuringian potash mine Volkenroda operated from 1909 until the early 1990s. The production residues from potash processing were deposited on the Menteroda potash tailings heap. Due to the total volume of approximately 21 million m³ of tailings, an average of up to 150,000 m³ of highly mineralized spoil heap leachate is generated annually due to precipitation.

LMBV mbH, as the legal successor of the former potash mine, is responsible for the decommissioning of the mine, as well as averting dangers 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 completed, full flooding, the so-called wet decommissioning of the Volkenroda/Pöthen mine workings, the spoil heap waters are to be transported to the central brine storage basin in Wipperdorf and, in accordance with the permit, discharged in a controlled manner into the receiving water body.

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

durable
corrosion-resistant
abrasion-resistant

To further meet the high demands for environmental protection, the pipeline was to be permanently and fully monitored during operation to detect even minor damage before an actual pipe burst occurs. Based on the requirements mentioned above, the egeplast 3L Leak Control System was selected. The pipe system is based on a PE 100-RC core pipe, which is laminated with diffusion-tight and electrically conductive aluminum that immediately reports even the smallest damage. An additional extruded protective jacket made of modified PE provides electrical insulation against the ground.

The required fittings, such as bends, reducers, connection pieces and T-pieces, were manufactured customer-specifically in the fitting production at egeplast, in accordance with the requirements for the 3L Leak Control. Approximately 8.6 km of the dimension OD 180 mm were used, which could be delivered on large drums of 500 m each. The also required 5 km of the larger dimension OD 200 mm were delivered as rods of 20 m length. The Installation of the 3L Leak Control pipeline was carried out both in open trench Installation, using the milling process, and in 10 separate horizontal directional drillings. The connections of the pipes and fittings required for this purpose were made according to DVS 2207 using butt welding and electrofusion welding.

The guided horizontal drillings were carried out by BLK Bohrteam GmbH from Mertendorf. The pipe laying using the milling method and open trenching was performed by ARGE Hoch- und Tiefbau Ebeleben GmbH from Ebeleben with HELMER Rohrleitungsbau from Apfelstädt.

To immediately receive a corresponding notification in the event of damage to the pipe system during operation and to localize the damaged area as precisely as possible, LMBV divided the electrical monitoring into 15 separate measuring circuits, which are centrally consolidated in one monitoring unit. In the event of damage, a fault signal is automatically triggered in the affected measuring circuit, so that in an emergency, the pipe section to be inspected is precisely defined and the fault can be quickly and accurately localized.

The operational readiness of the monitoring for each individual measuring circuit was measured by specialists from egeplast and handed over to the client in full working order. After construction began in 2019, the project was completed in 2021. The construction costs for the measure amount to approximately €14 million, financed partly by the German federal government and partly by the Free State of Thuringia.