Notes from the Demolition Edge

Between 1986 and 1995 429 hydrofracturing tests have been carried out in six, now abandoned, coal mines and two coal bed methane boreholes at depths between 600 and 1950 m within the greater Ruhr region in western Germany. From these tests, stress magnitudes and orientations of the stress tensor are derived. The majority of hydrofracturing tests were carried out from mine galleries away from mine workings in a relatively undisturbed rock mass. These data along with detailed information have been disclosed recently. In combination with already published material, we provide the first comprehensive stress database of the greater Ruhr region. Our study summarizes results of the extensive in situ stress test campaign and assigns quality to each data record using the established quality ranking schemes of the World Stress Map project. The stress magnitudes suggest predominantly strike-slip stress regime, where the magnitude of the minimum horizontal stress, Shmin, is half of the magnitude of the maximum horizontal stress, SHmax, implying that the horizontal differential stress is high. We observe no particular change in the stress gradient at depth throughout the Carboniferous layers and no significant difference between tests carried out in coal mines and deep boreholes. The mean SHmax orientation varies between 133 ± 13° in the easternmost located Friedrich-Heinrich coal mine and 168 ± 23° in the westernmost located Westfalen coal mine. The mean SHmax orientation, based on 87 data records from this as well as already published studies, of 161 ± 43° is in good agreement with the regional stress orientation observed in Northwestern Europe. The presented public database provides in situ stress magnitude and stress orientation data records that are essential for the calibration of geomechanical numerical models on regional and/or reservoir scales for, among others, assessing stability issues of borehole trajectories, caverns, and georeservoirs in general. For an application example of this database, we estimate slip and dilation tendencies of major geological discontinuities, discovered during the 700-year-long coal mining activities in the region. The result shows that the discontinuities striking in the N-S and NW-SE directions have a higher slip tendency compared to the ones striking ENE-WSW and NNW-SSE, whereas a high dilation tendency is observed for discontinuities striking NNW-SSE and a low dilation tendency for the ones striking ENE-WSW.

Between 1986 and 1995 429 hydrofracturing tests have been carried out in six, now abandoned, coal mines and two coal bed methane boreholes at depths between 600 and 1950 m within the greater Ruhr region in western Germany. From these tests, stress magnitudes and orientations of the stress tensor are derived. The majority of hydrofracturing tests were carried out from mine galleries away from mine workings in a relatively undisturbed rock mass. These data along with detailed information have been disclosed recently. In combination with already published material, we provide the first comprehensive stress database of the greater Ruhr region. Our study summarizes results of the extensive in situ stress test campaign and assigns quality to each data record using the established quality ranking schemes of the World Stress Map project. The stress magnitudes suggest predominantly strike-slip stress regime, where the magnitude of the minimum horizontal stress, Shmin, is half of the magnitude of the maximum horizontal stress, SHmax, implying that the horizontal differential stress is high. We observe no particular change in the stress gradient at depth throughout the Carboniferous layers and no significant difference between tests carried out in coal mines and deep boreholes. The mean SHmax orientation varies between 133 ± 13° in the easternmost located Friedrich-Heinrich coal mine and 168 ± 23° in the westernmost located Westfalen coal mine. The mean SHmax orientation, based on 87 data records from this as well as already published studies, of 161 ± 43° is in good agreement with the regional stress orientation observed in Northwestern Europe. The presented public database provides in situ stress magnitude and stress orientation data records that are essential for the calibration of geomechanical numerical models on regional and/or reservoir scales for, among others, assessing stability issues of borehole trajectories, caverns, and georeservoirs in general. For an application example of this database, we estimate slip and dilation tendencies of major geological discontinuities, discovered during the 700-year-long coal mining activities in the region. The result shows that the discontinuities striking in the N-S and NW-SE directions have a higher slip tendency compared to the ones striking ENE-WSW and NNW-SSE, whereas a high dilation tendency is observed for discontinuities striking NNW-SSE and a low dilation tendency for the ones striking ENE-WSW.

Between 1986 and 1995 429 hydrofracturing tests have been carried out in six, now abandoned, coal mines and two coal bed methane boreholes at depths between 600 and 1950 m within the greater Ruhr region in western Germany. From these tests, stress magnitudes and orientations of the stress tensor are derived. The majority of hydrofracturing tests were carried out from mine galleries away from mine workings in a relatively undisturbed rock mass. These data along with detailed information have been disclosed recently. In combination with already published material, we provide the first comprehensive stress database of the greater Ruhr region. Our study summarizes results of the extensive in situ stress test campaign and assigns quality to each data record using the established quality ranking schemes of the World Stress Map project. The stress magnitudes suggest predominantly strike-slip stress regime, where the magnitude of the minimum horizontal stress, Shmin, is half of the magnitude of the maximum horizontal stress, SHmax, implying that the horizontal differential stress is high. We observe no particular change in the stress gradient at depth throughout the Carboniferous layers and no significant difference between tests carried out in coal mines and deep boreholes. The mean SHmax orientation varies between 133 ± 13° in the easternmost located Friedrich-Heinrich coal mine and 168 ± 23° in the westernmost located Westfalen coal mine. The mean SHmax orientation, based on 87 data records from this as well as already published studies, of 161 ± 43° is in good agreement with the regional stress orientation observed in Northwestern Europe. The presented public database provides in situ stress magnitude and stress orientation data records that are essential for the calibration of geomechanical numerical models on regional and/or reservoir scales for, among others, assessing stability issues of borehole trajectories, caverns, and georeservoirs in general. For an application example of this database, we estimate slip and dilation tendencies of major geological discontinuities, discovered during the 700-year-long coal mining activities in the region. The result shows that the discontinuities striking in the N-S and NW-SE directions have a higher slip tendency compared to the ones striking ENE-WSW and NNW-SSE, whereas a high dilation tendency is observed for discontinuities striking NNW-SSE and a low dilation tendency for the ones striking ENE-WSW.

Between 1986 and 1995 429 hydrofracturing tests have been carried out in six, now abandoned, coal mines and two coal bed methane boreholes at depths between 600 and 1950 m within the greater Ruhr region in western Germany. From these tests, stress magnitudes and orientations of the stress tensor are derived. The majority of hydrofracturing tests were carried out from mine galleries away from mine workings in a relatively undisturbed rock mass. These data along with detailed information have been disclosed recently. In combination with already published material, we provide the first comprehensive stress database of the greater Ruhr region. Our study summarizes results of the extensive in situ stress test campaign and assigns quality to each data record using the established quality ranking schemes of the World Stress Map project. The stress magnitudes suggest predominantly strike-slip stress regime, where the magnitude of the minimum horizontal stress, Shmin, is half of the magnitude of the maximum horizontal stress, SHmax, implying that the horizontal differential stress is high. We observe no particular change in the stress gradient at depth throughout the Carboniferous layers and no significant difference between tests carried out in coal mines and deep boreholes. The mean SHmax orientation varies between 133 ± 13° in the easternmost located Friedrich-Heinrich coal mine and 168 ± 23° in the westernmost located Westfalen coal mine. The mean SHmax orientation, based on 87 data records from this as well as already published studies, of 161 ± 43° is in good agreement with the regional stress orientation observed in Northwestern Europe. The presented public database provides in situ stress magnitude and stress orientation data records that are essential for the calibration of geomechanical numerical models on regional and/or reservoir scales for, among others, assessing stability issues of borehole trajectories, caverns, and georeservoirs in general. For an application example of this database, we estimate slip and dilation tendencies of major geological discontinuities, discovered during the 700-year-long coal mining activities in the region. The result shows that the discontinuities striking in the N-S and NW-SE directions have a higher slip tendency compared to the ones striking ENE-WSW and NNW-SSE, whereas a high dilation tendency is observed for discontinuities striking NNW-SSE and a low dilation tendency for the ones striking ENE-WSW.

Abstract. Between 1986 and 1995, 429 hydrofracturing tests have been carried out in six now-abandoned coal mines and two coal bed methane boreholes at depths between 600 and 1950 m within the greater Ruhr region in western Germany. From these tests, stress magnitudes and orientations of the stress tensor are derived. The majority of hydrofracturing tests were carried out from mine galleries away from mine workings in a relatively undisturbed rock mass. These data along with detailed information have been disclosed recently. In combination with already published material, we provide the first comprehensive stress database of the greater Ruhr region. Our study summarises the results of the extensive in situ stress test campaign and assigns quality to each data record using the established quality ranking schemes of the World Stress Map project. The stress magnitudes suggest predominantly strike-slip stress regime, where the magnitude of the minimum horizontal stress, Shmin, is half of the magnitude of the maximum horizontal stress, SHmax, implying that the horizontal differential stress is high. We observe no particular change in the stress gradient at depth throughout the Carboniferous layers and no significant difference between tests carried out in coal mines and deep boreholes. The mean SHmax orientation varies between 133 ± 13∘ in the westernmost located Friedrich Heinrich coal mine and 168 ± 23∘ in the easternmost located Westphalia coal mine. The mean SHmax orientation, based on 87 data records from this and already published studies, of 161 ± 43∘ is in good agreement with the regional stress orientation observed in northwestern Europe. The presented public database provides in situ stress magnitude and stress orientation data records that are essential for the calibration of geomechanical numerical models on regional and/or reservoir scales for, among others, assessing stability issues of borehole trajectories, caverns, and georeservoirs in general. For an application example of this database, we estimate slip and dilation tendencies of major geological discontinuities, discovered during the 700-year-long coal mining activities in the region. The result, although burdened by high uncertainties, shows that the discontinuities striking in the N–S and NW–SE directions have a higher slip tendency compared to the ones striking ENE–WSW and NNW–SSE, whereas a high dilation tendency is observed for discontinuities striking NNW–SSE and a low dilation tendency for the ones striking ENE–WSW. The stress orientation database is available under https://doi.org/10.24406/fordatis/200 (Kruszewski et al., 2022a), the stress magnitude database is available under https://doi.org/10.24406/fordatis/201 (Kruszewski et al., 2022b), whereas the hydrofracturing test reports are available under https://doi.org/10.24406/fordatis/222 (Kruszewski et al., 2022c).

Between 1986 and 1995 429 hydrofracturing tests have been carried out in six, now abandoned, coal mines and two coal bed methane boreholes at depths between 600 and 1950 m within the greater Ruhr region in western Germany. From these tests, stress magnitudes and orientations of the stress tensor are derived. The majority of hydrofracturing tests were carried out from mine galleries away from mine workings in a relatively undisturbed rock mass. These data along with detailed information have been disclosed recently. In combination with already published material, we provide the first comprehensive stress database of the greater Ruhr region. Our study summarizes results of the extensive in situ stress test campaign and assigns quality to each data record using the established quality ranking schemes of the World Stress Map project. The stress magnitudes suggest predominantly strike-slip stress regime, where the magnitude of the minimum horizontal stress, Shmin, is half of the magnitude of the maximum horizontal stress, SHmax, implying that the horizontal differential stress is high. We observe no particular change in the stress gradient at depth throughout the Carboniferous layers and no significant difference between tests carried out in coal mines and deep boreholes. The mean SHmax orientation varies between 133 ± 13° in the easternmost located Friedrich-Heinrich coal mine and 168 ± 23° in the westernmost located Westfalen coal mine. The mean SHmax orientation, based on 87 data records from this as well as already published studies, of 161 ± 43° is in good agreement with the regional stress orientation observed in Northwestern Europe. The presented public database provides in situ stress magnitude and stress orientation data records that are essential for the calibration of geomechanical numerical models on regional and/or reservoir scales for, among others, assessing stability issues of borehole trajectories, caverns, and georeservoirs in general. For an application example of this database, we estimate slip and dilation tendencies of major geological discontinuities, discovered during the 700-year-long coal mining activities in the region. The result shows that the discontinuities striking in the N-S and NW-SE directions have a higher slip tendency compared to the ones striking ENE-WSW and NNW-SSE, whereas a high dilation tendency is observed for discontinuities striking NNW-SSE and a low dilation tendency for the ones striking ENE-WSW.

Between 1986 and 1995 429 hydrofracturing tests have been carried out in six, now abandoned, coal mines and two coal bed methane boreholes at depths between 600 and 1950 m within the greater Ruhr region in western Germany. From these tests, stress magnitudes and orientations of the stress tensor are derived. The majority of hydrofracturing tests were carried out from mine galleries away from mine workings in a relatively undisturbed rock mass. These data along with detailed information have been disclosed recently. In combination with already published material, we provide the first comprehensive stress database of the greater Ruhr region. Our study summarizes results of the extensive in situ stress test campaign and assigns quality to each data record using the established quality ranking schemes of the World Stress Map project. The stress magnitudes suggest predominantly strike-slip stress regime, where the magnitude of the minimum horizontal stress, Shmin, is half of the magnitude of the maximum horizontal stress, SHmax, implying that the horizontal differential stress is high. We observe no particular change in the stress gradient at depth throughout the Carboniferous layers and no significant difference between tests carried out in coal mines and deep boreholes. The mean SHmax orientation varies between 133 ± 13° in the easternmost located Friedrich-Heinrich coal mine and 168 ± 23° in the westernmost located Westfalen coal mine. The mean SHmax orientation, based on 87 data records from this as well as already published studies, of 161 ± 43° is in good agreement with the regional stress orientation observed in Northwestern Europe. The presented public database provides in situ stress magnitude and stress orientation data records that are essential for the calibration of geomechanical numerical models on regional and/or reservoir scales for, among others, assessing stability issues of borehole trajectories, caverns, and georeservoirs in general. For an application example of this database, we estimate slip and dilation tendencies of major geological discontinuities, discovered during the 700-year-long coal mining activities in the region. The result shows that the discontinuities striking in the N-S and NW-SE directions have a higher slip tendency compared to the ones striking ENE-WSW and NNW-SSE, whereas a high dilation tendency is observed for discontinuities striking NNW-SSE and a low dilation tendency for the ones striking ENE-WSW.

Between 1986 and 1995 429 hydrofracturing tests have been carried out in six, now abandoned, coal mines and two coal bed methane boreholes at depths between 600 and 1950 m within the greater Ruhr region in western Germany. From these tests, stress magnitudes and orientations of the stress tensor are derived. The majority of hydrofracturing tests were carried out from mine galleries away from mine workings in a relatively undisturbed rock mass. These data along with detailed information have been disclosed recently. In combination with already published material, we provide the first comprehensive stress database of the greater Ruhr region. Our study summarizes results of the extensive in situ stress test campaign and assigns quality to each data record using the established quality ranking schemes of the World Stress Map project. The stress magnitudes suggest predominantly strike-slip stress regime, where the magnitude of the minimum horizontal stress, Shmin, is half of the magnitude of the maximum horizontal stress, SHmax, implying that the horizontal differential stress is high. We observe no particular change in the stress gradient at depth throughout the Carboniferous layers and no significant difference between tests carried out in coal mines and deep boreholes. The mean SHmax orientation varies between 133 ± 13° in the easternmost located Friedrich-Heinrich coal mine and 168 ± 23° in the westernmost located Westfalen coal mine. The mean SHmax orientation, based on 87 data records from this as well as already published studies, of 161 ± 43° is in good agreement with the regional stress orientation observed in Northwestern Europe. The presented public database provides in situ stress magnitude and stress orientation data records that are essential for the calibration of geomechanical numerical models on regional and/or reservoir scales for, among others, assessing stability issues of borehole trajectories, caverns, and georeservoirs in general. For an application example of this database, we estimate slip and dilation tendencies of major geological discontinuities, discovered during the 700-year-long coal mining activities in the region. The result shows that the discontinuities striking in the N-S and NW-SE directions have a higher slip tendency compared to the ones striking ENE-WSW and NNW-SSE, whereas a high dilation tendency is observed for discontinuities striking NNW-SSE and a low dilation tendency for the ones striking ENE-WSW.

Between 1986 and 1995 429 hydrofracturing tests have been carried out in six, now abandoned, coal mines and two coal bed methane boreholes at depths between 600 and 1950 m within the greater Ruhr region in western Germany. From these tests, stress magnitudes and orientations of the stress tensor are derived. The majority of hydrofracturing tests were carried out from mine galleries away from mine workings in a relatively undisturbed rock mass. These data along with detailed information have been disclosed recently. In combination with already published material, we provide the first comprehensive stress database of the greater Ruhr region. Our study summarizes results of the extensive in situ stress test campaign and assigns quality to each data record using the established quality ranking schemes of the World Stress Map project. The stress magnitudes suggest predominantly strike-slip stress regime, where the magnitude of the minimum horizontal stress, Shmin, is half of the magnitude of the maximum horizontal stress, SHmax, implying that the horizontal differential stress is high. We observe no particular change in the stress gradient at depth throughout the Carboniferous layers and no significant difference between tests carried out in coal mines and deep boreholes. The mean SHmax orientation varies between 133 ± 13° in the easternmost located Friedrich-Heinrich coal mine and 168 ± 23° in the westernmost located Westfalen coal mine. The mean SHmax orientation, based on 87 data records from this as well as already published studies, of 161 ± 43° is in good agreement with the regional stress orientation observed in Northwestern Europe. The presented public database provides in situ stress magnitude and stress orientation data records that are essential for the calibration of geomechanical numerical models on regional and/or reservoir scales for, among others, assessing stability issues of borehole trajectories, caverns, and georeservoirs in general. For an application example of this database, we estimate slip and dilation tendencies of major geological discontinuities, discovered during the 700-year-long coal mining activities in the region. The result shows that the discontinuities striking in the N-S and NW-SE directions have a higher slip tendency compared to the ones striking ENE-WSW and NNW-SSE, whereas a high dilation tendency is observed for discontinuities striking NNW-SSE and a low dilation tendency for the ones striking ENE-WSW.

Anthracite Labor Wars: Tenancy, Italians, and Organized Crime in the Northern Coalfield of Northeastern Pennsylvania, 1897–1959

Memorials and the Mine Disaster in Monongah, West Virginia: From Trauma to an Italian Global Memoryscape

Over the past decade, there has been a burgeoning interest in two overlapping areas of the humanities and social sciences: memory and geography or, more specifically, the study of human space. Both of them have spawned an extraordinary amount of interesting work, work that has in effect created new fields of study and inquiry. The concern with memory, for example, has branched out to include such increasingly prevalent forms of writing as personal memoirs and autobiography, which nearly every fiction writer of note has attempted, to say nothing of the outpourings of academics, scientists, public figures, and so forth. The national fixation on recollection, confession, and witness has run the whole gamut from public confession-as in the Clinton-Lewinsky scandal-to various studies of the meaning of collective memory, extended reflection and analyses of instances of it, plus numerous chronicles embodying it. I shall have more to say about that later. In addition, and somewhat on the margins, has been a serious, sometimes bitter inquiry into the authenticity of certain memories, as well as, at the other, calmer end of the spectrum, a remarkable academic analysis of the role of invention in such matters as tradition and collective historical experience. Some examples of intense and even anguished controversy are the following: Was Anne Frank's diary really hers, or was it so altered by publishers, members of her family, or others in its published form so as to conceal the disturbances in her domestic life? In Europe there has been a great and often acerbic debate over the meaning of the Holocaust, with a whole range of opinions as to what happened, why it happened, and

Re/constructing collective memory: coal-mining Heritage Museums in Sawahlunto, Indonesia

This study investigated the mineralogical and chemical characteristics of ochreous precipitates and mine water samples from abandoned Upper Carboniferous hard coal mines in an extensive former mining area in western Germany. Mine water characteristics have been monitored and assessed using a multi-methodological approach. Thirteen mine water discharge locations were sampled for hydrochemical analysis, with a total of 46 water samples seasonally collected in the whole study area for stable isotopic analyses. Mineralogical composition of 13 ochreous precipitates was identified by a combination of powder X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FE-SEM/EDS). Results showed that abandoned mine drainage was characterized by circumneutral pH, Eh values ranging from 163 to 269 mV, relatively low concentrations of Fe and Mn, and was dominated by HCO3− > SO42− > Cl− > NO3− and Na+ > Ca2+ > Mg2+ > K+. Goethite and ferrihydrite were the dominant precipitated Fe minerals, with traces of quartz, dolomite, and clay minerals. Some metal and metalloid elements (Mn, Al, Si, and Ti) were found in the ochreous sediments. The role of bacteria in the formation of secondary minerals was assessed with the detection of Leptothrix ochracea. The δ18O and δ2H values of mine water plotted on and close to the GMWL and LMWLs indicated local derivation from meteoric water and represented the annual mean precipitation isotopic composition. Results might help to develop strategies for the management of water resources, contaminated mine water, and public health.

<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>