Pebbles on the Beach of the “Great Transformation”: Lesser Memories of Coal in the Ruhr Metropolis

Six decades ago, Germany’s Ruhr region began its slow transition out of coalmining and the coal-powered iron and steel industry. Over the last twenty years a blue economy has developed in their stead pivoting on the lead market ‘resource efficiency’, while the Ruhr Metropolis has gained recognition for the rehabilitation of its heavily polluted environment. This managed transition has seen the rise of eco-industries – sustainable energy production, research and development in universities, environmental technology companies, industrial heritage and nature tourism, as well as consumptive industries seen as eco-adjacent, foremost sports, leisure, arts and culture. These are central to an overarching strategy for the establishment of a sustainable, climate-resilient and future-proof Ruhr region and a globally significant investment site in the heart of Europe.

Longitudinal Rise in Seroprevalence of SARS-CoV-2 Infections in Children in Western Germany—A Blind Spot in Epidemiology?

SARS-CoV-2 infection rates in children and adolescents are often underestimated due to asymptomatic or oligosymptomatic infections. Seroprevalence studies can reveal the magnitude of “silent” infections in this age group and help to assess the risk of infection for children but also their role in spreading the disease. In total, 2045 children and their parents from the Ruhr region were finally included after the exclusion of drop-outs. Seroconversion rates among children of all age groups increased from 0.5% to 8% during the study period and were about three to fourfold higher than the officially registered PCR-based infection rates. Only 41% recalled symptoms of infection; 59% were asymptomatic. In 51% of the infected children, at least one parent also developed SARS-CoV-2 antibodies. Depending on local incidences, the rates of seroconversion rose to different levels during the study period. Although the dynamics of infection within the study cohort mirrors local incidence, the figure of SARS-CoV-2 infections in children and adolescents appears to be high. Reported contact with SARS-CoV-2-infected individuals in the same household carries a high risk of infection.

In Situ Stress State of the Ruhr Region (Germany) and Its Implications for Permeability Anisotropy

In this study, we carried out reactivation potential analysis of discontinuities revealed from four exploration boreholes penetrating heavily faulted and folded Upper Carboniferous rock strata of the Ruhr region. We performed this study based on the notion that slip is controlled by the ratio of shear to effective normal stresses acting on a pre-existing plane of weakness in the prevailing stress field configuration. The results of this analysis were supported by indicators of localized fluid flow, both on micro- and macro-scales, which confirm relationship between secondary permeability and in situ stress state in the Ruhr region. Findings from this study, in conjunction with results of destructive laboratory testing, indicate that the steep NW–SE- and NNE–SSW-striking planar discontinuities are likely to be either close to the critical state or critically stressed in the in situ stress configuration in the Ruhr region. These planar structures, as evidenced by indicators of localized permeability, are the main fluid pathways in the studied region. The NE–SW-striking discontinuities, on the other hand, are most likely to be closed and hydraulically inactive in the prevailing stress state. Based on results gained from this study, implications for utilization of deep geothermal energy in the region were discussed.

Environmental Justice and Green Infrastructure in the Ruhr. From Distributive to Institutional Conceptions of Justice

Over the last 50 years, the Ruhr region experienced a remarkable transformation from an industrial to a post-industrial region. With regard to the rehabilitation of the environmental damages of more than 100 years of coal mining and steel production, investment in green infrastructure, and the creation of regional landscape parks constituted one of the main pillars of the economic and physical transformation of the region. However, little is known about the social effects of this green transformation. Many observers state that the Ruhr area is sharply divided by an east–west line (the A40 Highway) and in fact the Emscher zone was hit most by environmental degradation. We argue that environmental justice is a question of scale. While on the regional scale, the investments made in the Emscher zone can be seen as a trial to balance and repair a long-standing unequal provision with environmental qualities (not least parks), on a smaller scale (i.e., cities and neighbourhoods) we can demonstrate that in the cities of the Emscher zone environmental inequality is still observable. Some neighbourhoods benefit stronger from investment in regional parks and green infrastructure than others. The paper will describe the Emscher green regeneration programme and will give detailed insights into two cities of the Ruhr (including maps and data analysis).

Compatibility of family and work: how do families in the Ruhr region/Germany deal with mobility-related challenges?

Mobility-related challenges severely impact on everyday lives of families with young children. Since this is especially true for families with children younger than ten, here we focus on the mobility coping strategies and patterns they develop to reconcile family and work life. The paper is based on a qualitative empirical study in which 40 mothers and fathers were interviewed in the Ruhr region in 2018. The results show that their most pressing mobility challenges are related to time-based and financial restrictions. Common strategies in adapting to these challenges are commuting by car, by involving the grandparent generation in childcare, and by reducing the mother’s (paid) working hours. Especially the interviewed mothers see the latter as a compromise rather than a satisfactory measure. Families who cannot resort to these strategies might be faced with social exclusion.

“Guest Workers” in Mining

Over the past five to six decades, oral history has become a complex and diverse tool, not only for uncovering and analysing individual and collective patterns of memory but also to inscribe them into public historical narratives. In the wake of the decline of the mining industry in the Ruhr region, local history workshops, academic historians, filmmakers, and museum practitioners began to construe miners and mining communities as historical subjects from the bottom up. Throughout this time, personal narrations played an increasingly important role as both a source of research and a tool for public historical representations. Using the case study of the Ruhr area, this article deals with the functions of public oral history narrations about the region’s mining past. It will particularly address the question of how the work and life stories of Turkish immigrant labourers, officially labelled as “guest workers”, have been represented in regional historical culture. To what extent did they become narrative agents in the Ruhr’s historiography, from a democratic and participatory “history from below” to an increasingly institutionalised approach in public history?

The in-situ stress state of the Rhine-Ruhr region and its implications for the geothermal energy utilization

<p>The Rhine-Ruhr region is one of the largest metropolitan areas in Europe, with more than 10 million inhabitants, located in western Germany. The region is defined by the rich coal-bearing layers from the upper Carboniferous period, extracted as early as the 13<sup>th</sup> century and belonging to the sub-Variscan Trough. In 2018, after more than 700 years of exploration, the last black coal mine was closed in the area. One of the most promising re-uses of the abandoned coal mines is the exploitation of geothermal energy sources. Additionally, to the geothermal energy extracted from existing mines, potential deep geothermal reservoirs within the Rhine-Ruhr, may exist at depths between 4.5 and 6 km, where Devonian limestones were found. Based on the available temperature profiles from deep exploration wells in the area, geothermal gradient amounts to 36.8<sup>o</sup>C/km and results in reservoir temperatures between 170<sup>o</sup>C and 220<sup>o</sup>C, which will enable not only heat but even electricity production. This study provides a comprehensive investigation of the full in-situ stress state tensor with its anisotropy and presents crucial physical formation and natural fracture properties. The data for this investigation was acquired from the extensive borehole logging and geomechanical campaigns carried out in deep coal exploration wells throughout the 1980s as well as from the recent shallow geothermal research wells. Acquired data allowed assessing critically-stressed, i.e. hydraulically active, fractures undergoing shear displacement, being primarily responsible for the future geothermal reservoir permeability. Extensive sets of microseismic, subsidence and drilling data were used to confirm the results of the analysis. Additionally, wellbore stability analysis and potential drill paths for the future medium-to-deep geothermal wells in the region were assessed. This study is a part of the 3D-RuhrMarie project, which aims to assess the intrinsic seismic risk within the Rhine-Ruhr region to promote safer and economically more efficient exploration and exploitation of the future geothermal resources.</p>

Establishing a 3D model for the Rhine-Ruhr region based on the geology and property distribution.

<p>The Rhine-Ruhr region is located in the state of North Rhine-Westphalia (NRW) in western Germany. Due to the transition from coal to low-carbon heat sources, potential locations in NRW must be explored regarding to their geothermal potential. The Bavarian area has shown for the last 20 years, that deep geothermal energy is both feasible and economical in Germany. Compared to the mentioned Molasse basin in south Germany, the geological setting is much more complex in the Rhine-Ruhr region. Based on a typical geothermal gradient of 30 °C/km, the optimal depth of a reservoir should be between 3000 m to 5000 m. In this depth, carbonate layers from Devonian times were identified in NRW. Due to the lack of accessibility, minor reservoir characterization was done, yet. Therefore, a geological model which reflects local lithological properties is essential for further geothermal projects. The model of the Rhine-Ruhr region is based on field surveys, top formations, geological sections and maps, respectively. The geometrical model is supplemented by rock properties, like density, porosity, and P- respectively S-wave velocities. These properties are derived from well logs, laboratory measurements and literature, transferring the derived properties to the grid require an analysis of upscaling techniques and distribution of such properties in the model. The result is a heterogeneous model representing the geological structure and rock property distribution of the Rhine-Ruhr region. Representative lithological units like Ruhrsandstone or interbedded coal, clay, and sandstone strata are also implemented as dominant fracture orientations. In this work we are considering several parameters to find a balance between the resolution of the model, property scaling and computational efficiency. One key aspect is that geological models are built with irregular grids while for our wave propagation simulations a regular and cartesian grid with equal grid spacing is required. Of course, such regular grids can be used for several modelling techniques and can be used as a basis for different studies. Overall goal is to evaluate local geological models to assess the feasibility of geothermal projects in the area.</p>