In December 2017, the District Government of Arnsberg/Germany, in its capacity as the mining authority for all of North Rhine-Westphalia, approved the colliery closure plan for the underground section of the central water drainage site at the Haus Aden mine (Figure 1). The approval was granted on the basis of a specialist report, compiled by a group of expert surveyors contracted by the North Rhine-Westphalia Ministry for Environment and Agriculture, which has refuted initially asserted concerns. The full report can be viewed at https://www.bra.nrw.de/3747177 or a summary report is available from https://www.bra.nrw.de/3747190. Both versions can be downloaded.
This means RAG AG, Essen/Germany, can commence the proposed process of gradually raising underground mine water levels at the Haus Aden 2 shaft to 600 m below sea level. To monitor the controlled rise of mine water levels, an extensive monitoring programme and other checks have been defined by law in order to identify, eliminate or minimise unknown risks early on. This monitoring programme, the results of which are to be published, incorporates (among other things) a dense network of existing deep groundwater gauges and additional new groundwater gauges that are to be constructed 600 m below sea level by means of deep drilling. Metrological surveillance is also to be undertaken at ground surface level. This ensures that the mine water, which is rising slowly over several years, is thoroughly tested for contamination by heavy metals and PCB. In this connection, the surveyors make the assumption that the rising mine water levels will continue to reduce the existing pollution levels that are already very low. In light of this, and on the basis of the legal specifications of the Federal Mining Act, RAG’s application for approval of the colliery closure plan was approved. Furthermore, the RAG has voluntarily undertaken to construct and operate two pilot facilities for clearing PCB, one of which will be at the Haus Aden site. (RAG/Si.)