Permanently Safe Transportation of Tailings Brine
Durable, corrosion- and abrasion-resistant as well as fully monitored — such were the specifications of the LMBV (Lausitzer und Mitteldeutsche Bergbauverwaltungsgesellschaft) for a new 13.5-km brine transportation pipeline from Menteroda to the centralised stacked brine basin in Wipperdorf. Against this background, the egeplast 3L Leak Control System with 100-percent leakage monitoring was the option of choice. The big drums rendered installation with state-of-the-art and environmentally-friendly methods very efficient and did not require more than a few pipe connections.
The Thuringian potash mine in Volkenroda was operated from 1909 until the early 1990’s. The production residues from potash processing were dumped on the Menteroda landfill set aside for residues from potash processing. The total volume of residues left in open-air storage, which has come to amount to approx. 21 million m³, has resulted in an average of 150,000 m³ of rainfall-induced highly mineralised dump water per year.
As the legal successor of the former potash mine, LMBV mbH is responsible for maintaining the mine as well as for averting any associated threats to public safety and for continuously ensuring the safety of its surface equipment.
Since the mid 1990’s, the dump waters have been introduced into the mine via the then still open Volkenroda shaft as well as, later on, by means of a borehole for flooding. Once flooding has been completed (the so-called wet stabilisation of the mine workings in Volkenroda/Pöthen), the dump water is meant to be transported to the central stacked brine basin in Wipperdorf for controlled draining off into the onsite pre-flooder as authorised.
For this purpose, the LMBV commissioned a 13.5-km pipeline from the Menteroda stacked brine basin to the connecting point with the preexisting dump water in Sollstedt. According to the plan, the new pipeline to be established for the purpose of discharging the saline water was to fulfill the following high requirements:
To meet the resulting extra high demands related to environmental protection, the pipeline was to be monitored permanently und fully while in operation to ensure that even minor damages would be detected before any actual pipe burst.
Given these requirements, the egeplast 3L Leak Control System was selected. It is based on a core pipe made of PE 100-RC and clad with diffusion-tight and electroconductive aluminium which immediately detects and signals even very minor damages. Its electrical isolation from the ground is achieved by means of an additional extruded protective sheath made of modified PE.
Customised versions of the required fittings such as bends, reductions, connection- and T-pieces which met the same requirements as the 3L Leak Control were manufactured in the egeplast Fittings Manufacturing Unit.
Approx. 8.6 kms featuring dimensions of OD 180 mm could be delivered on large drums @ 500 m. The 5 kms of pipe which featured a larger dimension, OD 200 mm, were delivered as 20-m rods. The installation of the 3L Leak Control took place using the open-trench method, milling and 10 separate flush drillings. The required connections between the pipes and fittings were performed by means of butt welding and electrofusion welding in conformance with the DVS 2207.
The controlled horizontal drillings were performed by BLK Bohrteam GmbH from Mertendorf. Pipe laying which involved milling and open-trench installation was carried out by ARGE Hoch-und Tiefbau Ebeleben GmbH from Ebeleben in cooperation with HELMER Rohrleitungsbau from Apfelstädt.
To ensure that any potential damage to the pipe system during operation will be reported immediately, indicating the site of the damage as precisely as possible, LMBV decided to split the electrical monitoring process into 15 separate measuring circuits which come together in one central monitoring unit. If a damage occurs, an error signal in the affected measuring circuit will be triggered automatically, meaning that in the event of an acute incidence, the pipe sector which needs to be examined can be readily identified, thus making it possible to quickly and precisely locate the damage.
The egeplast specialists performed measurements on every single measuring circuit to confirm it was operational, and the system was fully functional when handed over to the customer. The construction works started in 2019 and were completed recently in 2021. The construction costs for the measure amount to approx. 14 million €, which were in part funded by the Federal Government of Germany, and in part by the Free State of Thuringia.
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