Simulation of the hydrogeologic effects of oil-shale mining on the neighbouring wetland water balance: case study in north-eastern Estonia

The water balance of wetlands plays an integral role in their function. Developments adjacent to wetlands can affect their water balance through impacts on groundwater flow and increased discharge in the area, and they can cause lowering of the wetland water table. A 430 km² area was selected for groundwater modelling to asses the effect of underground mining on the water balance of wetlands in north-eastern Estonia. A nature conservation area (encompassing Selisoo bog) is within 3 km of an underground oil-shale mine. Two future mining scenarios with different areal extents of mining were modeled and compared to the present situation. Results show that the vertical hydraulic conductivity of the subsurface is of critical importance to potential wetland dewatering as a result of mining. Significant impact on the Selisoo bog water balance will be caused by the approaching mine but there will be only minor additional impacts from mining directly below the bog. The major impact will arise before that stage, when the underground mine extension reaches the border of the nature conservation area; since the restriction of activities in this area relates to the ground surface, the conservation area’s border is not sufficiently protective in relation to underground development.     

Maribo—A new CM fall from Denmark

Abstract– Maribo is a new Danish CM chondrite, which fell on January 17, 2009, at 19:08:28 CET. The fall was observed by many eye witnesses and recorded by a surveillance camera, an all sky camera, a few seismic stations, and by meteor radar observatories in Germany. A single fragment of Maribo with a dry weight of 25.8 g was found on March 4, 2009. The coarse‐grained components in Maribo include chondrules, fine‐grained olivine aggregates, large isolated lithic clasts, metals, and mineral fragments (often olivine), and rare Ca,Al‐rich inclusions. The components are typically rimmed by fine‐grained dust mantles. The matrix includes abundant dust rimmed fragments of tochilinite with a layered, fishbone‐like texture, tochilinite–cronstedtite intergrowths, sulfides, metals, and carbonates often intergrown with tochilinite. The oxygen isotopic composition: (δ¹⁷O = ?1.27‰; δ¹⁸O = 4.96‰; Δ¹⁷O = ?3.85‰) plots at the edge of the CM field, close to the CCAM line. The very low Δ¹⁷O and the presence of unaltered components suggest that Maribo is among the least altered CM chondrites. The bulk chemistry of Maribo is typical of CM chondrites. Trapped noble gases are similar in abundance and isotopic composition to other CM chondrites, stepwise heating data indicating the presence of gas components hosted by presolar diamond and silicon carbide. The organics in Maribo include components also seen in Murchison as well as nitrogen‐rich components unique to Maribo.     

Ballast water sampling as a critical component of biological invasions risk management

The human mediated transfer of harmful organisms via shipping, specifically via ballast water transport, leading to the loss of biodiversity, alteration of ecosystems, negative impacts on human health and in some regions economic loss, has raised considerable attention especially in the last decade. Ballast water sampling is very important for biological invasions risk management. The complexity of ballast water sampling is a result of both the variety of organism diversity and behaviour, as well as ship design including availability of ballast water sampling points. Furthermore, ballast water sampling methodology is influenced by the objectives of the sampling study. In the course of research conducted in Slovenia, new sampling equipment for ships' ballast water was developed and tested. In this paper new ballast water sampling methods and equipment together with practical shipboard testing results are presented.     

Dissolved uranyl complexed species in artificial seawater

The distribution of dissolved uranyl species was calculated on the basis of the stability constants published elsewhere and compared with the results obtained from the experiments performed in artificial seawater. According to the distributions calculated and electrochemical and spectrophoto-metrical measurements performed in model electrolytes and artificial seawater (pH=8.2) in the presence of sufficient hydrogen peroxide, uranium most probably predominates in the form of a mixed uranyl-dicarbonato-hydrogenperoxo complex. The results obtained could be applied to the natural marine photic zone.The mixed complex has to be taken into account as an additional form of dissolved uranium species influencing their cycle in natural water systems. Recent discovery of the presence of hydrogen peroxide in the surface waters of seas has challenged a long-held notion of the prevalence of uranyl-carbonato complexes in seawater.     

Marine sampling by scuba diving. 3. Sampling procedures for measurement of mercury concentrations in estuarine waters and seawater

A method for sampling estuarine waters and seawater by scuba diving is described. Samples taken from the Krka River Estuary on the eastern Adriatic coast were analysed for mercury content using cold vapour atomic absorption spectrometry (CVAAS). Mercury levels as low as 1 ng dm⁻³ were determined and these are among the lowest values reported to date. A simple contamination free procedure for the preconditioning of sample containers in the sea was applied. Sampling of water by divers is particularly useful when the intermediate layer in an estuary has to be identified and sampled, as well as for obtaining detailed vertical concentration profiles for mercury and other trace elements.     

Petrological, organic geochemical and geochemical characteristics of coal from the Soko mine, Serbia

A petrological, organic geochemical and geochemical study was performed on coal samples from the Soko Mine, Soko Banja basin, Serbia. Ten coal and two carbonaceous clay samples were collected from fresh, working faces in the underground brown coal mine from different parts of the main coal seam. The Lower Miocene, low-rank coal of the Soko Mine is a typical humic coal with huminite concentrations of up to 76.2 vol.%, liptinite less than 14 vol.% and inertinite less than 11 vol.%. Ulminite is the most abundant maceral with variable amounts of densinite and clay minerals. Sporinite and resinite are the most common macerals of the liptinite group. Inertodetrinite is the most abundant maceral of the inertinite group. The mineral-bituminous groundmass identified in some coal samples, and carbonaceous marly clay, indicate sub-aquatic origin and strong bacterial decomposition. The mean random huminite reflectance (ulminite B) for the main coal seam is 0.40 ± 0.05% Rr, which is typical for an immature to early mature stage of organic matter.The extract yields from the coal of the Soko Banja basin ranges from 9413 to 14,096 ppm, in which alkanes constituted 1.0–20.1%, aromatics 1.3–14.7%, asphaltenes 28.1–76.2% and resins 20.2–43.5%. The saturated hydrocarbon fractions included n-C₁₅ to n-C₃₂, with an odd carbon number that predominate in almost all the samples. The contents of n-C₂₇ and n-C₂₉ alkanes are extremely high in some samples, as a contribution of epicuticular waxes from higher plants. Acyclic isoprenoid hydrocarbons are minor constituents in the aliphatic fraction, and the pristane/phytane (Pr/Ph) ratio varies between 0.56 and 3.13, which implies anaerobic to oxic conditions during sedimentation. The most abundant diterpanes were abietane, dehydroabietane and 16α(H)-phyllocladane. In samples from the upper part of the coal seam, diterpanes are the dominant constituents of the alkane fraction. Polycyclic alkanes of the triterpane type are important constituents of alkane fractions. The occurrence of ββ- and αβ-type hopanes from C₂₇ to C₃₁, but without C₂₈, is typical for the Soko Banja coals.The major and trace elements in the coal were analysed using X-ray fluorescence (XRF), and inductively coupled plasma-mass spectrometry (ICP-MS). In comparison with world lignites, using the geometric mean value, the coal from the Soko Banja Basin has a high content of strontium (306.953 mg/kg). Higher values than the world lignites were obtained for Mo (3.614 mg/kg), Ni (8.119 mg/kg), Se (0.884 mg/kg), U (2.642 mg/kg) and W (0.148 mg/kg). Correlation analysis shows inorganic affinity for almost all the major and trace elements, except for S, which has an organic affinity.     

Land degradation analysis of mine-impacted zone of Kolubara in Serbia

This paper presents the effect of land-use changes on land degradation by utilization of remote sensing methods and the Gavrilovi? erosion potential method, due to surface mining activities in the period 2001–2011. Studied area includes the zone of influence of the Rudarski basen Kolubara, which covers the exploitation area of the Kolubara coal basin in the Republic of Serbia. The analysis is based on the processing of Landsat 5 satellite images from 2001 and 2011. In the analysis of satellite images, the supervised classification method was used. The results suggest that the observed spatial–temporal area is exposed to erosion as a result of land-use changes. Preliminary conclusion is that the dominant anthropogenic factor, responsible for changes in land use, is pronounced through the mining activity, industrialization, construction as well as agricultural activities. Very small changes in land use that occurred in the period 2001–2010 have led to relatively small amount of change from the aspect of land degradation. Also, due to the planned exploitation of the mine which included into account the sustainability of ecosystems, primarily through appropriate conservation measures, RB Kolubara is not in danger of a possible erosion processes that could undermine the stability of the basin.     

Seismic response analysis using characteristic ground motion records for risk‐based decision‐making (3R method)

The concept of intensity‐based assessment for risk‐based decision‐making is introduced. It is realized by means of the so‐called 3R method (response analysis, record selection and risk‐based decision‐making), which can be used to check the adequacy of design of a new building or of the strengthening of an existing building by performing conventional pushover analysis and dynamic analysis for only a few ground motions, which are termed characteristic ground motions. Because the objective of the method is not a precise assessment of the seismic risk, a simple decision model for risk acceptability can be introduced. The engineer can decide that the reliability of a no‐collapse requirement is sufficient when collapse is observed in the case of less than half of, for example, seven characteristic ground motions. From the theoretical point of view, it is shown that the accuracy of the method is acceptable if the non‐linear response history analyses are performed at a low percentile of limit‐state intensity, which is also proven by means of several examples of multi‐storey reinforced concrete frame buildings. The 3R method represents a compromise between the exclusive use of either pushover analysis or dynamic analysis and can be easily introduced into building codes provided that its applicability is further investigated (e.g. asymmetric structures and other performance objectives) and that the procedure for the selection of characteristic ground motions is automated and readily available to engineers (www.smartengineering.si).     

Using Temperature Fluctuation Measurements to Estimate Meteorological Inputs for Modelling Dispersion During Convective Conditions in Urban Areas

We examine the performance of several methods to estimate meteorological inputs for modelling dispersion in urban areas during convective conditions. Sensible heat flux, surface friction velocity and turbulent velocities are estimated from measurements of mean wind speed and the standard deviation of temperature fluctuations at a single level on a tower at two suburban sites and at one urban site in Riverside, California. These estimates are compared with observations made at these sites during a field study conducted in 2007. The sensible heat flux is overestimated in the urban area, while it is underestimated at a suburban site when temperature fluctuations are used in the free convection formulation to estimate heat flux. The bias in heat flux estimates can be reduced through a correction that depends on stability. It turns out that the bias in heat flux estimates has a minor effect on the prediction of surface friction velocity and turbulent velocities. Estimates of sensible heat flux, surface friction velocity and turbulent velocities are sensitive to estimates of aerodynamic roughness length, and we suggest estimating the aerodynamic roughness length through detailed micrometeorological measurements made during a limited field study. An examination of the impact of the uncertainty in estimating surface micrometeorology on concentrations indicates that, at small distances from a surface release, ground-level concentrations computed using estimates of heat flux and surface friction compare well with the those based on observed values: the bias is small and the 95% confidence interval of the ratio of the two concentrations is 1.7. However, at distances much larger than the Obukhov length, this confidence interval is close to 2.3 because errors in both friction velocity and heat flux affect plume spread. Finally, we show that using measurements of temperature fluctuations in estimating heat flux is an improvement on that based on the surface energy balance, even when net radiation measurements are available.