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Geophysical tools to study the near surface distribution of the tailings in the Smaltjärnen repository, south-central Sweden; a feasibility study

Tavakoli Saman, Rasmussen Thorkild Maack

Acta Geophysica

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2022

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Vol. 70, no 1

141--159

EN

Two geophysical field works were conducted during a feasibility study in the Smaltjärnen tailing repository of the abandoned Yxsjöberg mine, located in south-central Sweden. The aim of these studies was to evaluate the applicability of the geophysical methods in tailing characterizations i.e. to (I) identify the approximate level of the underground water table, (II) understand the vertical and lateral distribution of the tailings and (III) image the variations within the internal stratigraphy of the tailings. Ground Penetrating Radar (GPR) data with medium–low-frequency antennas (300, 250 and 100 MHz) and Self-Potential (SP) data using the Streaming Potential Phenomena (SPP) were collected to characterize the top few meters of the subsurface and understand the water flow direction. Results from the mineralogical and geochemical studies of the drill-core samples were incorporated in the study to complement the interpretations of the geophysical data. Three distinct layers had been earlier identified based on the interpretations of the geochemical data which agreed well with the GPR interpretations in this study: (I) oxidized tailing (new), (II), transition zone and (III) old tailing which is located under the water table. The SP data, unexpectedly, indicated that the groundwater flows from the lake i.e. lower altitudes, towards the higher altitudes which probably is related to the uncertainties resulted from 2D data while the actual water flow direction can be best studied in 3D, or, dominant effect from the metal contents. Complementary geophysical studies including a 2D-SP survey and Direct Current (DC) electrical resistivity measurements are suggested to improve the present understanding of the morphology of the site.

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Application of the conductive method in the engineering geology: Ruczaj district in Kraków, Poland, as a case study

Klityński Wojciech, Oryński Szymon, Dinh Chau Nguyen

Acta Geophysica

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2019

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Vol. 67, no. 6

1791--1798

EN

The Ruczaj district in Kraków is the potential building area of high flat blocks for inhabitants. This area is built of the gypsum basement covered by the soil and impermeable clay beds with several meters of thickness. The flat blocks must be set on the textured gypsum layer. In the result of the rainfall and static pressure of the blocks, the water with SO42− increases up to the groundwater level, become the great threat for the flat blocks. The water creates specific hydrogeological conditions occurring in the zone of the building’s foundations. To eliminate the mentioned threat, we should determine precisely the thickness of the soil and impermeable clay as well as the depth of the gypsum basement. Based on the electromagnetic parameters of the geological formations, the Ground Conductivity Meter and DC resistivity methods were used to solve the mentioned problems.

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Możliwości oceny stanu technicznego wałów przeciwpowodziowych na podstawie badań geofizyki inżynierskiej

Ostrowski S., Lasocki M.

Przegląd Geologiczny

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2014

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Vol. 62, nr 10/2

671--679

EN

Catastrophic floodings caused by floodbank and dam failures draw attention to urgent need of modernization of these facilities in Poland. The task specified above requires precise and fast methods of technical condition assessment of existing facilities. Present method of assessment of the geotechnical parameters of flood embankments and its geological setting is limited to sampling and geotechnical probing in discrete intervals, which are too sparse to recognize zones of weakening or unfavourable geologic conditions that might constitute critical zones for floodbank stability. This paper presents results and conclusions of experimental survey concluded in 2014 attempting to apply near-surface geophysical methods to floodbank condition assessment. In author's opinion, three techniques applied yielded most reliable results. Moreover the methods – electric resistivity tomography; seismic refraction tomography and multichannel analysis of surface waves can be optimised for utilisation for fast surveys on floodbanks. Authors give attention to results of above mentioned three geophysical methods and only briefly discuss the applicability of other near-surface geophysical methods for issues concerning floodbank technical condition.

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Wykorzystanie przypowierzchniowych badań geofizycznych w rozpoznaniu budowy geologicznej na przykładzie stref osuwiskowych w Karpatach

Ostrowski S., Rybak-Ostrowska B., Lasocki M.

Przegląd Geologiczny

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2013

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Vol. 61, nr 1

67–-73

EN

The paper presents three examples of application of geophysical surveys carried out by the PBG Ltd. for the recognition of internal structure, geological background and mechanical properties of near- -surface rock medium at major landslides in the Polish Outer Carpathians. Geophysical data were used for developing an accurate geological model of the landslides. Geological features that cannot be detected by other means, e.g. faults in bedrock, and exact location and shape of the shear plane were delineated in two-dimensional mode on the sections.