Professor Dr. Walter Semmler: A German Mine Water Pioneer

Prof. Dr. Walter Semmler (1903–1990) was a ground-breaking German hydrogeologist who conducted practical mine water research in Germany, mainly related to dewatering, but also on tracer tests and potential environmental impacts of mine water. In addition, his contributions to professional associations in Germany and the formation of water authorities in the Ruhr Coal Mining District was noteworthy.     

Parallel file system performances in fusion data storage

High I/O flow rates, up to 10 GB/s, are required in large fusion Tokamak experiments like ITER where hundreds of nodes store simultaneously large amounts of data acquired during the plasma discharges. Typical network topologies such as linear arrays (systolic), rings, meshes (2-D arrays), tori (3-D arrays), trees, butterfly, hypercube in combination with high speed data transports like Infiniband or 10G-Ethernet, are the main areas in which the effort to overcome the so-called parallel I/O bottlenecks is most focused.The high I/O flow rates were modelled in an emulated testbed based on the parallel file systems such as Lustre and GPFS, commonly used in High Performance Computing. The test runs on High Performance Computing–For Fusion (8640 cores) and ENEA CRESCO (3392 cores) supercomputers. Message Passing Interface based applications were developed to emulate parallel I/O on Lustre and GPFS using data archival and access solutions like MDSPLUS and Universal Access Layer. These methods of data storage organization are widely diffused in nuclear fusion experiments and are being developed within the EFDA Integrated Tokamak Modelling – Task Force; the authors tried to evaluate their behaviour in a realistic emulation setup.     

Ground water withdrawal and land subsidence in northeastern Saxony (Germany)

Several large open pit lignite mines are located in northeastern Saxony, Germany. To guarantee the production of electric power until the year 2026, a couple of these pits have to be extended. Most of the open pits are, at most, 120–150 meters deep. Nevertheless, a large area is affected by ground water withdrawal. There is a concern that differential subsidence due to mine dewatering might cause vertical stress and building damage. The area of investigation is a 2km² large building complex built in the early 1970’s. It will be dewatered to a depth of 70 m below the surface, resulting in subsidence that has been predicted by both analytical and empirical methods. From empirical calculations, based on subsidence measurements, a total subsidence of 0.2–0.5 m was predicted. Analytical calculations, on the other hand, using the principles of Terzaghi’s consolidation theory, yielded an average possible subsidence of 1.1–1.6 m by the end of 2026. These differences might be due to the fact that sand and gravel lenses in the tertiary clays have not been fully dewatered, or that some of the less permeable units will subside very slowly, or that the sediments were compacted more by the Pleistocene glaciers than expected. Taking into consideration the calculations as well as the known measurements, a subsidence of at least 0.2 m is highly likely. Due to the geological situation, differential subsidence and the associated damage is possible for part of the area.     

Passive Grubenwasserreinigung als Alternative zu aktiven Systemen

Um kontaminiertes Grubenwasser langfristig kostengünstig reinigen zu k?nnen, sind Methoden mit geringstm?glichen Investitions- und Unterhaltungskosten n?tig. Dazu wurden in Gro?britannien und Deutschland in den zurückliegenden Jahren unterschiedliche passive Reinigungssysteme in Betrieb genommen (z. B. anoxische Karbonatkan?le, konstruierte Feuchtgebiete, reaktive Barrieren, Gro?oberfl?chenfilter).     

Predicting and Forecasting Mine Water Parameters Using a Hybrid Intelligent System

Water Resources Management - Water treatment plants need to stock chemicals and have enough energy as well as human resources to operate reliably. To avoid a process interruption, proper planning...     

A Hard Coal Miner at the Haarmannsbrunnen (Haarmann Fountain) in Osnabrück (Germany)

Mine Water and the Environment -