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.

Impact of selected waste applications on soil compaction

In the years 2014–2017, a field experiment was carried out, in which two types of waste were applied to soil. One of them was mineral waste – carboniferous rock from a hard coal mine, and the other – organic waste – post-fermentation sludge from agricultural biogas-producing plant. The experiment was an example of an action, in which soil management was associated with their drainage effects on the soil. The waste was applied to the light soil of low utility value, included in the V bonitation class (in polish soil quality classification) and the 6th complex of agricultural suitability (weak rye). According to the WRB classification, it was Haplic Podzol (PZha) developed from the post-glacial sand. The aim of the study was to analyze changes in soil compaction caused by a single introduction of waste. During the four-year study (2014–2017), the durability of these changes was also observed. It was found that the best effects of reducing the soil compaction were obtained as a result of the combined application of two wastes: carboniferous rock and post-fermentation sludge. Introduction of waste into the soil was also permanent, as differences resulting from the soil management continued in the fourth year of the experiment.

Human Capital Formation During the First Industrial Revolution: Evidence from the use of Steam Engines

We examine the effect of technical change on human capital formation during England's Industrial Revolution. Using the number of steam engines installed by 1800 as a synthetic indicator of technological change and occupational statistics to measure working skills (using HISCLASS), we establish a positive correlation between the use of steam engines and the share of skilled workers at the county level. We use exogenous variation in carboniferous rock strata (containing coal to fuel the engines) to show that the effect was causal. While technological change stimulated the formation of working skills, it had an overall negative effect on the formation of primary education, captured by literacy and school enrolment rates. It also led to higher gender inequality in literacy.

Management of Carboniferous Rock and Waste Mineral Wool in the Context of Current Polish Legislation

This paper presents the legal aspects of the management of wastes that can be used as sorbents in environmental protection. The legal status of wastes with mineral characteristics - Carboniferous rock and mineral wool from horticulture - is discussed, where it is found that the number of legal acts cause difficulties in the utilisation of such wastes.