The Haus Aden 2 shaft from RAG Aktien-gesellschaft, Essen/Germany, in Bergkamen is currently being filled. In 2023, submersible pumps are to pump mine water at depth through cladding tubes. The filling work will be completed by the end of the year. RAG has submitted the planning notification to North Rhine-Westphalia’s mining authority in order to raise and discharge mine water from the Haus Aden site into the Lippe river. RAG has provided an initial overview of the project in this planning notification, which makes the procedure transparent right from the start.
After coal mining has ended, the long-term optimisation of mine water drainage is a central element of the perpetual obligations. The mine water plan for the Ruhr region envisages that, in the future, the mine water will only be raised at six central water drainage sites. Haus Aden in Bergkamen is one of these future central water drainage sites.
No mine water is currently being raised at Haus Aden. The site is currently being converted into a well drainage system (Figure 1). For this purpose, Thyssen Schachtbau, Mülheim an der Ruhr/Germany, is building three cladding tubes in the shaft. This happens step by step. First of all, the tubes are constructed section by section and then the corresponding shaft section is filled with concrete. Work started at the end of September 2019. At present, approximately 120 m of concrete has been poured – a total of around 5,000 m3 of concrete. The remaining 660 m should be completely filled by the end of the year and the pumps should be operational by the end of 2023.
RAG expressly supports the Water City project in its planning work. As a result, a new functional building based on a harmonious and coordinated overall plan is also to be jointly turned into an architectural landmark. RAG is planning a power house at the site, which will contain a well system with lifting equipment for the pumps and pipelines that, in the future, will regulate the mine water level in the eastern Ruhr region. Preserving the shaft frame is not compatible with these plans. The power house will not fit under the existing construction. Instead, it is to be built on the dismantled shaft frame foundation in order to transfer the huge total load of the lifting equipment and the three suspended pipelines, each weighing 500 t, into the ground. This is the latest point at which the remaining steel construction’s statics can no longer be guaranteed.
In order to resume drainage after the target horizon has been reached, RAG requires a new permit relating to water laws in order to raise and discharge mine water into the Lippe river. The planning notification marks the start of the water law procedure, which also includes an Environmental Impact Assessment (EIA). This planning notification has meanwhile been sent by the mining authority to authorities, associations, communities and other public bodies. The mining authority will soon invite these recipients to a scoping meeting. At this meeting, the content and scope of the documents submitted by RAG in the water law procedure requiring an EIA will be discussed.
The water law procedure will also deal with the issue of removing traces of PCB present in mine water. To investigate the extent to which it is possible to separate these traces from the mine water, RAG already began operating container-scale pilot facilities at the Haus Aden and Ibbenbüren sites about a year and a half ago to filter out the smallest traces of PCB from a large quantity of mine water and examine them analytically. The pilot facility ran smoothly at both sites. At the end of 2019, the results were evaluated by an expert group consisting of ministries, authorities, RAG, IWW, surveyors and scientists. Since this group of experts also sees a need for further research – especially in the field of analytics – RAG has committed to further developing the analytical method within the framework of a doctorate in cooperation with the TH Georg Agricola University (THGA) based in Bochum/Germany. (RAG/Si.)