Rock mass mechanical characteristics in an opencut at bor copper mine

SummaryRock Mass Mechanical Characteristics in an Opencut at Bor Copper Mine Preliminary testing for the design of the new opencut, which will go to a depth of about 300 m, included testing rock mechanical characteristics. The character of the preliminary testing demanded by an engineering undertaking of this scale and the fundamental structural and physical properties of rock masses (fissuring, anisotropy, heterogeneity, natural stresses) are discussed and it is emphatically concluded that priority should go to in situ testing. Results are presented of determinations of the velocity of propagation of longitudinal elastic waves, elasticity modulus, coefficient of damage and shear strength parameters.With 7 Figures     

Transgressive overlap of a turbiditic sequence—priabonian of Ovče Pole,Macedonia

Flysch sequences develop normally from pelagic sediments, over a pre-flysch transitional unit, or from a well-developed transgressive base. A different situation has been observed in the western portion of the Upper Eocene flysch basin of Ov?e Pole, Macedonia, where deep-water turbidites appear almost directly over the eroded basement, transgressively overlapping the preexisting submarine relief. These relationships are explained as results of successive phases of subsidence in the basin. The outcrop area, situated between Titov Veles and Gradsko, represented a surface without deposition in the early depositional stages. Later subsidence introduced a turbiditic deposition into the domain without a break in sedimentation. Such cases may occur also in other flysch basins where lateral migration of the main depositional trough took place during the sedimentation.     

Evaluating the transferability of monthly water balance models under changing climate conditions

ABSTRACT

Monthly water balance models (MWBMs) are often used for making flow projections under climate change. As such, these models should provide accurate flow simulations; however, they are seldom evaluated in this regard. This paper presents a comprehensive framework intended for the evaluation of the applicability of MWBMs under changing climatic conditions. The framework consists of analyses of consistency in model performance, parameter estimates and simulated water balance components, and a subjective assessment of model transferability. Four MWBMs – abcd, Budyko, GR2M and WASMOD – are used to simulate runoff in the Wimmera catchment affected by the Millennium drought. Although abcd and Budyko slightly outperformed GR2M and WASMOD, none of the models performed well in transfer to the driest period. The greatest variability is detected in simulated groundwater storage and baseflow; thus, these model components should be improved and/or enhanced calibration strategies should be employed to advance the transferability of MWBMs under changing climate.     

Spectral distributions of the pressure gradient force errors in σ-coordinate spectral and grid-point models in an idealized case

Summary The spectral distributions of the pressure gradient force errors of the spectral and the finite-difference techniques used in combination with the vertical coordinate were examined in an idealized case of an atmosphere at rest and in hydrostatic equilibrium. The vertical temperature profile was piece-wise linear in lnp, with an inversion at the bottom. Trapezoidal mountains of different widths were used. The same amounts of input information were given to both the spectral and the finite-difference methods. In the rms sense, the spectral errors were generally much larger than those of the finite-difference method. However, on the larger and medium scales, a remarkable similarity of the error spectra of the two methods was found. The build up of the error of the spectral method occurs at the smallest scales. This may explain difficulties in documenting the error in higher resolution spectral models where the contribution to the total error in this part of the spectrum may be removed as the small-scale noise by the horizontal smoothing and/or filtering. In order to reduce the small-scale noise generation, the finite-difference pressure gradient force may be used in spectral models.With 6 Figures     

Geothermal model of Earth's crust and lithosphere for the territory of Yugoslavia: Some tectonic implications

Summary Deep sounding seismic data along nine profiles and measured values of the terrestrial heat flow were used to construct a geothermal model of the crust for the territory of Yugoslavia. The obtained data indicate that the lowest temperatures (250 – 350°C) at the crust base are in the region of the Outer Dinarides and the highest (900 – 1000°C) in the region of the Pannonian Basin and the Serbian-Macedonian Massif. The difference is associated with the changing heat flow which reaches the Earth's crust from the upper mantle. Based on the crustal temperature distribution, an approximate lithospheric thickness was estimated for the first time for the entire territory of Yugoslavia. It is largest under the Outer Dinarides, where it is up to 260 kilometres, and smallest under the Pannonian Basin and the Serbian-Macedonian Massif, only 40 – 50 kilometres.Before the separation of Slovenia, Croatia, Bosnia and Herzegovina and Macedonia.Presented at the International Meeting on Terrestrial Heat Flow and the Structure of Lithosphere, Bechyn Castle, Czech Republic, September 2 – 7, 1991.     

Eta model forecasts of tropical cyclones from Australian Monsoon Experiment: The model sensitivity

Summary The Australian Monsoon Experiment (AMEX) (10 January through 15 February 1987) has resulted in the first ever quality mesoscale data set in the Australian tropics. This provides the first observational confirmation of previous hypotheses, modelling experiments and refinement of the parametrization of convective processes. During the AMEX a large area of convective activity off northwestern Australia accompanied four tropical cyclones onset:Connie, Irma, Damien andJason. As already reported by the author, the Eta Model of the University of Belgrade and the National Meteorological Centre, Washington (UB/NMC), successfully predicted the development, structure, associated precipitation and tracks of these cyclones.Using again the AMEX tropical cyclone cases, in the present study the sensitivity of the Eta Model is examined with respect to the initial and boundary conditions, the vertical coordinate and orography, the location of the initial vortex, the surface fluxes of heat and moisture, the sea surface temperature and the Betts-Miller convection parametrization scheme.Also, some available forecasts of the AMEX tropical cyclones were intercompared. These included the forecasts obtained by the Eta Model, the T106 global (then) operational European Centre for Medium-range Weather Forecasts (ECMWF) model, the ECMWF T106 limited area model and the Florida State University (FSU) limited area model. A review of the intercomparison results suggests that the Eta Model is highly competitive with the other sophisticated models, both in terms of quality and the computational effort required.With 9 Figures     

Saxothuringian zone in Germany and Poland: differences and common features

The classical correlation by kossmat (1927) of the Saxothuringian belt of Germany with the West Sudetes of Poland is re-evaluated with special reference to the crystalline massifs of Munchberg and the Góry Sowie and the surrounding areas. Important common features are: Cambro-Ordovician magmatism and sedimentation; Silurian to Devonian radiolarian cherts in the low grade to unmetamorphosed units; Early Devonian (and older?) pressure-dominated metamorphism followed by rapid uplift; the incorporation of high pressure and mantle rocks; and Early Carboniferous mass flow deposits with ‘Saxothuringian’ clasts. Differing features in the West Sudetes are: tectonic contacts in and around the Góry Sowie are mostly subvertical and mainly (semi-)brittle (in contrast with subhorizontal and ductile contracts in the Münchberg); the Góry Sowie has undergone late re-equilibration of the earlier tectonic fabrics; an ophiolite juxtaposed with the Góry Sowie crystallized in (?) Devonian time and became only statically metamorphosed, as opposed to the regionally metamorphosed Cambro-Ordovician mafic rocks of the Saxothuringian belt; localized depocenters with Upper Devonian to Lower Permian elastic rocks relating to north-west trending strike-slip faults instead of the north-east trending cylindroidal foreland basin in the Saxothuringian. It is possible that the West Sudetes originated as an easterly continuation of the Saxothuringian belt, but then became involved, from the Late Devonian onwards, in a strike-slip system parallel with the margin of the East European Platform.     

Maximum precipitation for different short-term intervals

Summary A time series and extreme value analysis of maximum precipitation for distinct time intervals from 10 minutes to 1 day have been deduced for the observatory Zagreb-Gri ( = 45°49 and = 15°59,H _s = 157 m) for the period between 1908 and 1985. The Spearman rank correlation test revealed that the short-term precipitation maxima series for the time intervals of 10 to 30 minutes and 8 to 24 hours indicate no significant trend for the 95 percent probability level. The 40-minute to 4-hour precipitation maxima exhibited an increaese in recent time. Annual maximumt-minute precipitation was estimated using the Gumbel distribution for sets of data gradually prolonged with 10-year steps towards the past. The ratios (q) of maximum precipitation estimates for the shorter periods and of estimates for the reference period (1908–1985) have been calculated. Their positions according to the confidence interval on the reference estimates were determined. Confident extreme value estimates could be obtained using at least the 50–60 year data series.With 3 Figures     

Polycyclic aromatic hydrocarbons and their relationship to maturity and paleoenvironmental settings in lacustrine sediments of the Neogene Toplica Basin,Serbia

Journal of Paleolimnology - The study investigated the influence of maturity, biomass type, and depositional settings on the distribution and relative abundance of polycyclic aromatic hydrocarbons...     

Probabilistic yielding and cyclic behavior of geomaterials

In this paper, the novel concept of probabilistic yielding is used for 1‐D cyclic simulation of the constitutive behavior of geomaterials. Fokker–Planck–Kolmogorov equation‐based probabilistic elastic–plastic constitutive framework is applied for obtaining the complete probabilistic (probability density function) material response. Both perfectly plastic and hardening‐type material models are considered. It is shown that when uncertainties in material parameters are taken into consideration, even the simple, elastic‐perfectly plastic model captures some of the important features of geomaterial behavior, for example, modulus reduction with cyclic strain, which, deterministically, is only possible with more advanced constitutive models. Furthermore, it is also shown that the use of isotropic and kinematic hardening rules does not significantly improve the probabilistic material response. Copyright © 2010 John Wiley & Sons, Ltd.