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Abstract

The presented article describes the relationship between lithological and facies development of reservoir rocks in the area of the roof elevation of the Weissliegend sandstones, with a particular emphasis on the influence of elevation on the occurrence of low mineralization zones in the deposit area. To illustrate the variability of the deposit parameters, closely related to the facies and lithological conditions of the host rocks, three-dimensional lithological and geochemical models for two research areas were developed using the geostatistical methods and based on field observations and the sampling of the deposit. The research area includes parts of the Northern Elevation of Rudna and the surrounding depressions within the boundaries of the Sieroszowice and Rudna deposits. Based on cross-sections of the 3D models, a different deposit formation in the roof elevation area of sandstone formations has been characterized; the lithological profile is defined as „atypical” due to the absence of a copper-bearing shale series, the most characteristic layer for copper ore deposits in the Fore -Sudetic monocline. Large variations in the shape of the deposit and the irregular boundaries of both balance mineralization and enclaves of gangue have been confirmed. The presence of large-scale enclaves of igneous rock in the entire profile of the Lower Zechstein rocks (areas without the balance copper mineralization) and small areas of gangue (sandstone) enriched with anhydrite binders adjacent to the parts of balance deposit located in argillaceous sandstone has been revealed. The possibility of the occurrence of gangue, in the area of the roof elevation of the Weissliegend sandstones directly adjacent to the border with calcareous dolomite, and irregular gangue partings in sandstone formations in the balance deposit was indicated. In addition, small areas of strong enrichment in Cu sulphides were observed in the contact zones between sulphate and clay binders in the Weissliegend sandstone series.
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Abstract

The poorly cemented Ciężkowice poorly sorted sandstone and the compact Mucharz fine grain sandstone have been laboratory tested at the triaxial compressing conditions in thermo-pressurized chamber of a rigid press MTS-815. The confining pressure: P = σ₂ = gσ₃ range from 0 to 96 MPa and the temperature: T from 22°C to 120°C (simulated 500 m intervals from the surface to the depth of 3500 m). During (the) each test, the characteristics of deformation and the elastic wave velocity paths were simultaneously monitored. The volume density and longitudinal wave velocity showed a non-linear increase with the progress of simulated depth, a volume density growth by 1.6 to 4.0%, and the elastic wave velocity up to 250% of the primary value (surface condition), dependable on loading path, phase of deformation, and varying type of lithology. That may lead to wide error margin in a determination of rock’s engineering properties and also create discrepancies between the static parameters of rocks (Est, gνst) determined by standard laboratory load tests, and the dynamic parameters (Ed, νd) determined from the wave velocity and volume density.
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