STOP RUSSIAN INVASION!
united 24 logo savelife logo prytula foundation logo
Gold Search
MENTE ET MALLEO
UA RU

Salt karst

The influence of technogenic factors on the karst activization of Precarpathian salt sediments and karst natural lows

Vasyl Pavliuk
Scientific-Research Institute “Galurgiya”; Fabrychna 5a, 77300 Kalush, Ukraine; e-mail: notebooc@gmail.com
© 2016 Authors. This is an open access publication, which can be used, distributed and reproduced in any medium according
to the Creative Commons CC-BY 4.0 License requiring that the original work has been properly cited.

 

Abstract

The purpose of this article is to conduct an analysis of the technological and natural factors that influenced on development and intensification of the salt karst, located within Miocene salt-bearing sediments. Understanding the rules of the karst process is one way to help make the right decisions at the forecasting stage of these harmful exogenic geological processes. This is especially true of salt deposits, which are located in complex geological conditions (e.g. the Carpathian Foredeep). The development of the salt karst in the Precarpathians has shown that it is a complex multi-system process, where all the components have a significant impact on the results and they are directly related to each other.

The results of the completed research confirm that features of the spatial development of the karst processes within the Carpathian salt deposits are caused by the complex geological structures of the Miocene sediments. The spatial developments of the karst processes depend on the heterogeneity of the water penetration in the plans and sections of the salt-bearing deposits. This forms the predominant vector of the underground leaching intensity along the geological boundaries. Permeability and solubility of the salt bearing deposits along the bedding are higher, relative to the permeability and solubility across geological structures. Faults which occur across the strike of geological layers act as a containment of the karst processes along the geological borders.

 

Key words:  salt karst, gypsum-clay cap, Miocene salts, Precarpathians, potash salt mining

 

INTRODUCTION

The relevance of the environmental study of the exogenic processes (karst, suffusion, subsidence, flooding, landslides, contamination of soil, surface and groundwater) in the Precarpathian area  where influence of mining activities is connected with the fact that the mentioned processes are unstable and dangerous to both land and life (Blajda & Gorecki 2001; Frumkin 2013). The analysis of the manifestations of the exogenous events, within the influence of the potash mines has shown and organized the natural conditions and factors that affect the development of the karst. The intensity of the exogenic geological process (EGP) depends on the scale and peculiarities of the karst development (Pavliuk 2010) . A natural linear distribution of karst is found in the course of these works, both on the surface and on the inside of the geological deposits that correspond to the local geological aspects and are in accordance with the structures of the Carpathian region. These systematic patterns are noted throughout all the Precarpathians. These dependences lead to the conclusion of the decisive influence of the geological structures on the characteristics of the exogenic events within the region as both natural and man-made states. In each case, the estimation of the salt karst activation or the prediction of the effects of the process, along with a complex analysis and systematization of all the conditions and factors that may have an impact on its development, is required. Studies have shown that salt karst is a complex multi-system process where all the components have a significant impact on the results and are directly related to each other.

 

METHODS

The main conclusions of this work are derived from the processing and interpretation of the collected materials from the collections of the Lviv Geological Prospecting Enterprise and the Institute for Scientific Research "Halurhiya" Kalush. These scientific papers are devoted to this subject and were conducted as field observations during the execution of the government program: "The Monitoring of the Wide-spread Development of the Geotechnical EGP Processes and Phenomena Within the Lviv Region”. This program was done in order to provide geological maintenance to the GIAS (Government Information-Analytical System) (2006-2011). The main methods used in the preparation and conduct of this study were:

- analysis of the archive data and field methods;

- cooperation with the local government and regional offices of the Ministry of Emergency Situations;

- quantitative and qualitative analysis of the data, its classification, the creation of the appropriate GIS databases in Excel and the MapInfo environment, the comparison, correlation and multidimensional scaling of the results and others;

- verification of the results, allowing us to check the received information through to its final analysis.

The verification and the logical and methodological procedures for establishing the accuracy of the data on the basis of its consistency with the empirical and actual data, has mostly been tested on a computer using the "MapInfo" method of multilayer overlay mapping of the statistical and analytical information, creating diverse factual material in two-dimensional and three-dimensional images.

The purpose of this review is to conduct an analysis of the technological and natural factors that influence the development and the intensification of the salt karst and the harmful exogenic geological processes within the distribution of the Precarpathians salt-bearing Miocene sediments. The basis of the conducted review is to highlight the natural laws of karst development.

 

SALT KARST

Overall, karst is quite a complex phenomenon, which occurs in arrays of solvent deposits, where the rock dissolution becomes parallel to other hypergenesis processes and results in the formation of a weathered crust formation (Korotkevich 1970). Mainly, the most significant factor of salt karst activation is the anthropogenic activities. The man-made impact, without enough consideration of the geological structure of the deposits, natural laws and the physical properties of salt, can lead to the fact that the speed of the exogenous processes that occur in the undisturbed natural state, are accelerated many times.

World experience in research of the development and activation of exogenous processes and its impact on salt mines shows that the fundamental principle of that intensification was uncontrolled injection of groundwater and surface water in the mine voids. Some examples of recent large-scale accidents: Congo-1977; Solikamsk - Berezniki (Russia), 1995-2007; Hope Mine (Germany) - 1984 ; Ronnenberg - Schmalkalden (Germany), 1976 – 2010 (Wolkersdorfer 2008).


 

In total, there are more than 80 cases like these. In Ukraine, there were flooded quarry and mines in Kalush, in the Mine no. 2 in Stebnyk and catastrophic failures in Solotvyno (Transcarpathia). Regarding the Stebnyk deposits (Fig. 1), the practice of studying the causes of the injection (penetration) of surface water in volumes excavations (mine underground space) showed that in some areas at Mine no. 1 (43/2 drift, crosscut I / I, crosscut 4 / І, ort 99 / I, underground boreholes 469 and 477) and  at Mine no. 2 , (ort І/в, crosscut 17 / I, the chambers  155 \ I and 122 / І), geological and hydrogeological conditions were not properly understood during the performance of the underground work and contained no information on the nature, location and depth of the hazardous areas of surface water penetration, which are supergene altered rocks (zones) (Apsse et al. 1966; Lipnickij 1979). These circumstances have led to the insufficient evaluation of the cap pillar waterproof capacity in these areas.

 

Fig. 1. Distribution of potash and rock salt mines in the Precarpathians (after Bukowski & Czapowski 2009)

 

RESULTS AND DISCUSSION

An analysis of the shaft changes in depth and directions in the upper parts of the deposits (where is a high threat when the surface water has the ability to discharge in the underground workings), showed that there were cases where the underground workings was performed according to the requirements of economic expediency, and not as a security operation. For example, the "Eastern" Stebnyk mine shaft is located in the base of this part of the surface "salt mirrors". Here, there is a greater possibility of a concentration of infiltrated surface water, which could be one of the main causes of the extensive displays of underground leaks and the formation of collapsed karst on the day surface. It would have been more efficient, in terms of operational safety, to place the mine shaft 100m northwest, on the highest hypsometric salt surface mirrors of the plot (Fig. 2, 3). 

 

Fig. 2. Hypsometric surface plan of the “salt mirror” in the "Eastern" shaft area ; Mine no. 2 Field, Stebnyk (Stupnickij et al. 1995)

 

Moreover, it should be emphasized that underground mines were purposely created by man-made explosions. Even F. Permyakov, in the Solikamsk mine in 1941, noticed that in the carnallite rock there was a system of concentric cracks which eventually increased. The center of these cracks appears to be the location of these explosions. As a result, cracks were formed and the inrush of rock (the height of which may exceed 5-6 times the height of the roadway) and water increased the density of the deposits (Vahromeeva 1959).


Fig. 3. The geological cross-section of the shaft "East", Mine no. 2, Stebnyk (Stupnickij et al. 1995)

 

Examining the formation of the depression funnel within the aquifer sediments of the gypsum-clay cap, we can observe that 100% of its dependence is on the geological structure of the site. This depression funnel was formed in 1978 as the result of a rush of underground water in the chamber 115 (Fig. 4) which is located on the west side of the Mine no. 2 in Stebnyk. Initially, in 1980, it was a relatively isometric shape with a ratio of width to length of about 1: 2. Furthermore, there is an increase only along the geological boundaries and it is not expanding across structures. Moreover, the development of the water conical depression, in terms of limited time, had stopped when it reached the disjunctive tectonic disturbances that stopped it in a south-easterly direction and warped part of it in the western, north-western side. This confirms earlier assumptions expressed by "the role of transverse faults in the deterrence of salt karst processes along geological boundaries” (Pavliuk 2010a; Pavliuk 2010b). Water conical depressions that naturally grow by the increased permeability of sediments as resulting from the dynamic directed underground aquifer flows in salt-bearing deposits, further developed mainly just on the northwest side, increasing the catchment area and discharging more groundwater into underground workings. Now we have an isometric form, in terms of shape, with a ratio of about 4: 1 and boundaries that fully meet the geological structure of the area (Fig. 4). So, the increase of the permeability sediments, through the development of the karst geological processes along the border is a major factor in the growth of water inflows in the underground workings and not the increase of the catchment area (what repeatedly was spoken before (Stupnickij et al. 1995; Gajdin 2008), which in turn was the consequence.

 

Fig. 4. Location plan showing of development of exogenous processes in the area of Vyshnytsya river valley, western outskirts of the city Stebnyk

 

In 1998 a karst collapse formed on Pomiretska Street in Truskavets, within a private residential development (No. 54 and 56), as a result of backwater groundwater and its hydrogeological regime change that was due to the construction of the Sanatorium "Carpathians" on the east side. Collapse had a depth of 15m and an area of 6 × 4m. It was oval, elongated along geological boundaries with underlying salt-bearing sediments and brines filled to a depth of about 1m from the earth's surface. After the first collapse in autumn 2009, in different time periods within this sector, three similar ones were formed (fig. 5). They were oval, elongated and placed on a straight line parallel to the strike of geological boundaries.

 

Fig. 5. Location map of karst failures. Pomiretska street, Truskavets

 

In 2006, due to a water supply break in Borislav city (Modrychska Street 50) a karst collapse, with a diameter of up to 6m and a depth of 4m, was formed on the road. After repairing the supply break, the karst was covered. During the formation of karst, 30m to the northwest of this point, (along geological boundaries) at a well depth of 8m, the water disappeared.  Further along another 20m, a small surface dip formed with a diameter of 1.5m and a depth of 1m, which no one paid attention to. Obviously, when the water leaked from the supply line along this geological structure, it formed a cavern, up to 50-70m long, underneath apartment building number 50 and storing well and then as brine after 120m into the Tysmenytsia flood plain where it was discharged. The situation remained stable until the autumn of 2009, when under a house, located 15m from the water supply break (along the geological boundary), the earth's surface collapsed, but was restrained by the building’s foundation (fig. 6).

 

Fig. 6. Karst failures. Borislav

 

On Orlik Street in Stebnyk, several buildings are located in the area influenced by the earth's surface subsidence and karst failures (Fig. 7). Some of them have been destroyed and some have been damaged. This area stretches along geological boundaries and has dimension: 150m x 40m. The findings of the geotechnical work held here in 2000, on the elucidation of the causes of the karst processes, have not paid sufficient attention to the conditions and factors affecting their development and have not given proper evaluation to the important facts. For example, they had included as a basis, some local subsidence processes of an east-west direction, although of course, the whole process was developing in a north-west direction. The placement of the highest areas of the "salt mirror" and all the pressure boreholes (No. 1, 9, 10, 14) were virtually in a straight line, which coincided with the strike of the salt-bearing layers, subsidence zones, etc.


Fig. 7. Location map of exogenic processes. Orlyk street,  Stebnyk

 

A similar situation of the subsidence of the earth's surface created karst failures at the site of the main power inflow in Mine no. 2 in Stebnyk. At the beginning of 2010, in the Vyshnytsya Valley, an elongated trough subsidence of land and flooding of about 150m by 50m, was formed along geological boundaries, all as a consequence of the technologically activated underground leaching of salts. All surface karst failures found in this area were formed in a straight line.

 

CONCLUSIONS

  1. Irrational loading or man-made impacts on the natural environment of the salt-bearing sediments, lead to extreme increases in dangerous karst processes.
  2. The spatial development of karst processes in the Carpathian salt deposits are caused by complex geological structures of Miocene sediments.
  3. The spatial development of karst processes depends on the heterogeneity of water penetration in plane and section of the salt-bearing sediments. This forms the predominant vector of underground leaching intensity along geological boundaries.
  4. Permeability and solubility of salt bearing deposits along the bedding are higher relative to the permeability and solubility across these geological structures.
  5. Faults which occur across the strike of geological layers act as a containment of the karst processes along the geological borders.

 

REFERENCES

Apsse R., Voronova L., Kozlov S. et al. 1966. Otchet po rezultatam gidrogeologicheskih issledovanij na uchastke techi v shtreke 43/2 Rudnika No. 1 Stebnickogo kalijnogo kombinata (in Ukrainian). Fondy SKZ.

Blajda R., Gorecki J. 2001. Influence of lithological and structural factors on the development of salt karst in the ‘‘Wieliczka’’ salt mine deposit (in Polish). Geologia Kwartalnik AGH, 27, 329–340.

Bukowski K. & Czapowski G. 2009. Salt geology and mining traditions: Kalush and Stebnyk mines (Fore-Carpathian region, Ukraine). Geoturystyka,  3 (18), 27 - 34.

Frumkin A. 2013. Treatise on Geomorphology. Salt Karst. Academic Press. Volume 6.  407-424.

Gajdin A.,  2008. Vlijanie tehnogennoj  dejatelnosti  na  soljanoj  karst (in Ukrainian).  Ekologіja і prirodokoristuvannja, 11, 42-54.

Lipnickij  V.,  1979.  Geologo-gidrogeologicheskie  uslovija  proryva  vod  v  kameru  115/1

rudnika № 2 (in Ukrainian). Fondy SKZ.

Korotkevich G., 1970. Soljanoj karst (In Russian). Nedra, Leningrad.

Pavliuk V. 2010a. Vplyv pryrodno-tekhnohennykh faktoriv na formuvannya ekoloho-heolohichnykh umov v Peredkarpatti (na prykladi rodovyshcha kaliynykh soley „Stebnyk”) (in Ukrainian). Stroitelstvo i tehnogennaja bezopasnost, 33-34, 256 – 265.

Pavlyuk V. 2010b. Vplyv heolohichnykh faktoriv na ekzohenni protsesy miotsenovykh solenosnykh vidkladiv Ukrayinskoho Peredkarpattya (in Ukrainian). Heolohiya i heokhimiya horyuchykh kopalyn, 2 (151), 89 – 104.

Stupnickij V., Zheksimbaev M., Fedchenko A. et al. 1995. Otchet po pereocenke zapasov

kalijnyh solej Stebnickogo mestorozhdenija Lvovskoj oblasti (in Ukrainian). Fondi LGRE.

Vahromeeva V. 1959. Treshhinovatost soljanіh porod karnalitovoj zonі Verhnekamskogo

mestorozhdenija. Trudy Vsesojuznogo NI Instituta Galurgii (in Russian). 35, 53 – 70.

Wolkersdorfer Ch. 2008. Water management at abandoned flooded underground mines. Springer, 435.


 

HYDROGEOLOGICAL MODELING OF THE NATURAL PROCESSES OF LEACHING SALTS (KARST) UNDER PRECARPATHIANS CONDITIONS

Vasyl PAVLIUK

Scientific Research Institute «Galurgia» Lviv – Kalush, Ukraine. notebooc@gmail.com; galurgia@yandex.ua

Fabrichna str., 5a

Abstract. A review of the factors that have an effect on the evolution of the natural inhomogeneities of the karst processes that developed on the surface of the evaporite deposits of the Carpathian foredeep was done in this article.  The structural heterogeneity of the environment that influenced the spatial anisotropy of the speed of salt dissolution which formed the "salt mirror" depressions that are much lower than the local groundwater drainage bases was highlighted. The possible hydrogeological models of natural salts leaching was considered and presented in graphical ways. This allowed us to show the existence of relatively isolated hydraulic systems within a shared aquifer horizon of "gypsum-clay cap". Such systems are conditioned by the heterogenetic properties of water penetration in the plane and sections of "gypsum-clay cap" deposits, which formed special relative water penetration "channels" in this rock mass. This produced the same kind of separate relative isolated hydraulic systems. Their modes of operation are an essential factor in the development of karst processes and are a reflection of the hydrogeological and geological conditions of the site location.

Keywords: salt karst; "gypsum-clay cap"; "salt mirror"; hydrogeological model; hydraulic system

Introduction

Traditional salt production in the Ukrainian Carpathians existed for many centuries (Krzysztof 2009). But man-made interference with the environment has violated its natural state and intensified the negative exogenous processes, including karst. The salt karst must be considered separately from other types of karst. Select individual methods of research areas of salt karst is due to the fact that it, by its nature, has speed and conditions substantially different from other types, at least as with the existence of such structural elements as “gypsum-clay cap” (GCC), "salt mirror" with present horizon saturated brines on its surface, and with other peculiarities of the physical properties of rocks (Frumkin 2013), etc. Special characteristics of the building and content of Miocene complex rocks within the distribution of these salt deposits, form the hydrogeological properties of aquifers and their effects on the environment (Blajda 2001; Frumkin 1994). Trying virtual modeling of hydrogeological processes among the salt-bearing rocks will help us to better understand the nature of exogenous processes on their formation areas and their dependence from the geological and hydrogeological structures of the research area. This is especially important in the case of man-made interference when the exogenous processes often create negative consequences, sometimes reaching catastrophic proportions. There are a number of examples of catastrophic events in the world which show the same affects as those found in the Stebnyk and Kalush-Holyn mines. They are Congo - 1977, Solikamsk - Berezniki 1995 - 2007 (Russia), the Hope Mine, flooded in 1984, and the sink holes in mines in Ronnenberg - Schmalkalden 1976 - 2010, (Germany) etc. In total, there are more than 80 cases like these (Mozer 2010; Wolkersdorfer 2008; Whyatt 2008).

Discussion

In natural (not man-disturbed) conditions, in most cases, the Precarpathian salt karsts develop relatively slowly because almost invisible failed sinkholes form on the surface. However, powerful GCC deposits indicate that a permanent leaching of salt minerals takes place mainly in the plane of the "salt mirror". Power and composition of the GCC actually reflects the development nature of the weathering crust over the halogen species of the host layers (Bruthans 2000). The physical properties of brines of "salt mirror", namely their specific gravity grading in density,  would be to form relatively homogeneous surface-flat conditions for the dissolution of salt deposits, and therefore to form a relatively hypsometric flat surface of “salt mirror”, the level of which should be controlled by the basis of the  local groundwater discharge. However, in practice, this surface is intensely rugged with sharp drops of valleys and heights. Moreover, during the detailed study within the Stebnyk deposit of potassium salts, within the surface sediments of the Vorotyschenska and Polyanytska suites, were identified a number of "salt mirror" depressions which were formed well below the local drainage bases, which at first glance seems impossible. A fortiori is that as things stand, with low-infiltrating properties of sediments, the formation of significant amounts detected depressions requires that similar processes were permanent and lasting in time. Saturated brines that protect the surface of the salt rocks from being dissolved, have a much heavier weight than that of fresh water lying above and they cannot climb up to the local drainage bases without additional factors, thus giving access to the salt deposits, fresh water which is aggressive to the salt. Seemingly, the physical properties of the liquids contradict this state of affairs. So for example, the deepest depression of "salt mirror" within the Stebnyk potash deposit, is located in the north-western Stebnyk outskirts in the Vyshnytsya river valley and concerned with contact with the Vorotyschenska and Polyanytska suites. Based on facts of surface prospect - mapping drilling (Stupnyts'kyy 1995), the absolute lowest area mark of "salt mirror" is less than 150m. An altitude basis of local drainage, which is the channel r. Vyshnytsya, exceeds it at 170m. This is over 320m above sea level. But the vertical movements of brines exist in the conditions of the local geological structures. This is evidenced by the numerous exits to the surface brine natural sources, specific forms of crust (GCC) and scientific observations (Zaharov 1964).

Modeling

Significance of the environment study of exogenic processes (karst, suffusion, subsidence) in the areas of influence Precarpathians mines is connected with the fact that the selected processes are scored threat and are creating life dangerous conditions. The analysis manifestations of exogenous events within the influence of modern potash mines allowed to organize natural conditions and factors that affect the development of karst. Intensity of exogenic geological process development depends on scale and peculiarities of karst development (Pavliuk 2010). A natural linear distribution of karst is found in the course of these works, both on the surface and inside of geological deposits that corresponds to local geology aspects and accordance of structures Carpathian region. These systematic patterns are noted throughout all Precarpathians. These dependences lead to the conclusion about decisive influence of the geological structure on the characteristics of exogenic events in the region as natural and man-excited states. In each case, estimation of salt karst activation or prediction of the effects of the process, complex analysis and systematization of all the conditions and factors that may have an impact on its development is required. Studies have shown that salt karst is a complex multi-system process where all components have a significant impact on the results that are directly related to each other. A special part in prognosis of karst processes have to take place the study of the hydrogeological conditions of karst areas.

As an example of the complexity of the laws of the natural process of underground leaching of salts in the conditions of the Boryslav-Pokuttya Structure-Facies Zone (SFZ) of the Precarpathians, I can suggest the following hydrogeological model (Fig. 1).


Fig. 1. Hydrogeological model of the naturally caused karst process in the transverse of geological course of layers.

 

Legend to fig. 1: 1) relative water - permeable Quaternary sediments; 2) area of silting on the surface of GCC; 3) waterproof GCC deposits; 4) waterproof salt deposits Vorotyschenska suite; 5) relative water permeable deposits inside of GCC sediments and Vorotyschenska suite; 6) prevailing direction of underground water; 7) prevailing direction of underground brines; 8) zone of karst processes; 9) processes of the earth subsidence

The condition of the formation of anomalous depressions on the surface of the "salt mirror" significantly below the local base discharge underground waters to the day surface, must be the existence of upward flows of heavy brines and their replacement on the surface of the "salt mirror" by relatively lighter surface waters. The factors that shape this situation are:

- heterogeneous water permeable properties in the sediments of the GCC in planes and sections, which form relatively water permeable special "channels" in a given rock unit, which form kind of separate or relatively isolated hydraulic systems;

- higher levels of water permeable GCC deposits along geological boundaries than transverse of stratification (Pavliuk 2010);

- spatial mismatch in terms of areas of formation, distribution and discharge of underground water in GCC sediments.

- a single hydraulic system in the volume of GCC and surface of salt-bearing sediments which are relatively permeable rocks that are surrounded by water resistance stratums;

- availability of water sources, which could be from a violation of the zone silt on the surface GCC, or man-made circumstances, such as a drill well or a well, which disclose water permeable horizons in deposits of “«gypsum-clay cap»”;

- the difference of the hydraulic pressure which is formed in different parts of a single hydraulic system (due to height difference of hydraulic pillars H1 - H2);

- greater hydraulic resistance in the transverse of the deposits bedding (along line "L") than along the geological boundaries of layers (Layer "A").

The analysis and studies of the geological and hydrogeological conditions at the sites of karst activation on the street Orlik in the town of Stebnyk, enabled the use of the described model.


Fig. 2. Hydrogeological model of the naturally caused karst process.

Legend to fig. 2 see Fig. 1 Legend

 

As a consequence of this model, the top face of the “salt mirror” begins to form the deepening of  its surface, which will be significantly below the local base drainage level of the water discharge and will lead to the further deepening and development of karst processes in this or other neighboring areas.  For example, along the Layer "B" (Fig. 2).

Similarly, the process of the deepening of the surface of the "salt mirror", is due to the dissolution of salt deposits along the strike of the geological boundaries. In the plane, they coincide with the boundaries of the more permeable zones within and under the "salt mirror". Such areas may correspond to a hypergenic altered form of salt-bearing deposits, that are overlapped by the waterproof deposits of the GCC. When on a specific location above the "salt mirror", while being on top of the surface, aggressive water penetrated into undisturbed rocks and  also at the same time it moved along more permeable zones infiltrating under the surface of “salt mirror”.  The water moved along the layers to the point of its discharge and gradually dissolved salt that was bedding below.  At the same time, new layers of waterproof fine sediments of GCC were increasing from the top. Such a model shows the hydraulic movement of the aggressive waters with an appropriate difference of heights of the water supply area over the water discharge area and with the zone of high water conductivity at the contact point of the GCC soils with the indigenous salt bearing deposits that from top and bottom are limited waterproof rocks. The described model assists the removal of brine from the "salt mirror" surface to the day surface and from the depths that far exceed the local bases drainage (Fig. 3). A similar case of salt karst activation was fixed on Pomiretska street in Truskavets and Modrychska street in Borislav (Pavliuk 2011).

 


Fig. 3. The hydrogeological model of the naturally produced karst processes which are developing along the strike of geological structures (in cut).

Legend: (1; 2; 3; 4; 6; 7; 8; see Fig. 1 Legend); 5) relative water - permeable deposits in GCC soils

 

Separately, we should consider the tectonic contact zones of the Vorotyschenska salt - bearing deposits with the under salt rocks of the Polyanytska suite (Fig. 4). Because of the relatively lower content of salt minerals and because of the more sand-clay content in relation to the Vorotyschenskoyis suite, the deposits of the Polyanytskoyi suite are characterized by a higher permeability and also are within the tectonic contact and the fractured rocks have an even greater performance of water permeability. Therefore, under favorable conditions in these areas, the underground fresh waters reach considerable depths and by the hydraulic circuits, which are described in the previous examples, they dissolve the brine of the surface "salt mirror" and lift this to the day surface. As a consequence, during the most favorable terms of geological structure, wear has formed corresponding depressions in the "salt mirror" surface, that have different values within Stebnyk potash deposits. It is due to this model we watch the development the deepest depressions of the “salt mirror” of the Stebnyk potash deposit, which is located on the northwestern outskirts of the Stebnyk town in the Vyshnytsya river valley.

The results of the physical and mechanical properties of the GCC soils, taken from the location of the karst failure in the Vyshnytsya valley slope, have confirmed that the soils with the different sampling points during measuring degree of filtration and slaking properties, had a difference of several times (Tab. 1). Despite the low figures of filtering properties of the overlying sediments, the aggressive fresh water still came in with enough volume to the surface of the “salt mirror” and created there the development of a relatively active karst under the highly waterproof rocks of the GCC. On average, the parameters of the different clays (filtration coefficients) are within 10-4-10-6m/day (Cedergren 1977; Gol'dberg 1986). In our case, this figure ranges from 10-3 - 10-4m/day, according to our chemical analysis of water extracts taken from the same samples that were taken transversely from the extension of the geological structures of the GCC (Tab. 2). The rocks are characterized by a not quite stable composition. Of course those 6 samples do not reflect all the sections of the evaluated clays. Of course those 6 samples do not reflect all section of evaluated clays. Of course, there are as more water - permeable as more waterproof soils of GCC areas. For example, gypsum materials in the wall outcrops are visually observed in the shape of the separate fragments and as inhomogeneously distributed the nodule-like accumulations.

 


Fig. 4. Hydrogeological model of the karst natural process which develop along the tectonic contact of the salt-bearing deposits.

Legend: (1; 2; 3; 4; 6; 7; 8; see Fig. 1 Legend); 5) relative water-permeable deposits in GCC soils; 9) surface of aquifer in GCC sediments; 10) tectonic overthrust; 11) deposits of Polyanytska suite (secondary soil salting)

The described models of the salt karst argue the formation of the sharply intersected relief and the significant thickness of the GCC in terms of the upridging of the beds of the geological structures of the Boryslav-Pokuttya SFZ within the interior part of the Carpathian foredeep. The situation is different within the boundaries of the salt deposits of the Sambor SPZ, where the bedding of the indigenous salt-bearing deposits is flatter just as the surface of "salt mirror" and the thickness of the GCC is much smaller or sometimes it  is even absent under permeable and flooded alluvial deposits.

 

Date of sample

Soils volume weight, g/cm3

Soils spec. gravity, g/cm3

Grain size distribution, mm

Filtration coefficient, m/day

Slaking, %

0,1

0,1-0,01

0,01-0,05

0,05-0,001

0,001

Commin uted state

Densed state

5 min

10 min

30 min

1hour

1

2

5

7

8

9

10

11

12

13

14

15

16

17

18

1

2.12.2009

2

2,5

21,1

16,7

27,1

7,4

28

0,01

0,01

0,5

0,5

1

2

 

22,9

15,1

26,4

8

27,4

 

20% - за 24 год.

2

2.12.2009

1,9

2,3

29,2

7,9

52,6

4

6,2

0,04

0,01

0

0

0,5

0,5

 

30,6.

7

52,2

3,7

6,4

 

40% - за 24 год.

3

2.12.2009

1,9

2,3

35,3

8,6

39

2,6

14,3

0,02

0,02

0

0

5

5

 

36,3

6,5

41,6

2,1

13,3

 

40% - за 24 год.

4

2.12.2009

2

2,3

41,5

11,3

32,2

7,2

7,5

0,02

0,003

0

1

5

10

 

39,7

13,3

32,8

6,3

8,5

 

50% - за 24 год.

5

2.12.2009

2

2,5

4,3

12,6

26

12,7

44,2

0,04

0,007

0

0

0

5

 

 

 

 

5,8

10,3

27

11,8

44,9

 

 

50% - за 24 год.

6

2.12.2009

2

2,6

12,6

22,5

55,2

3,8

5,7

0,01

0,007

0

0

0

5

 

12

20,1

56,4

4,2

7,1

 

 

60% - in 24 hours.

Table 1. Results determining the physical and mechanical properties of GCC soils (Vyshnytsya river valley)

 

 

Date of sample

рН

Ca++,  mg/kg

Mg++, mg/kg

Na+, mg/kg

K+, mg/kg

HCO3 -, mg/kg

Cl -, mg/kg

SO4 2-, mg/kg

NH4+, mg/kg

Fe заг., mg/kg

NО3-, mg/kg

NО2-, mg/kg

СО3, mg/kg

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

1

2.12.09

7,9

391

109

49

79

366

30

1259

3

0

0

0

0

3

2.12.09

7,9

2796

158

71

179

305

20

7736

2

0

0

5

0

6

2.12.09

7,9

2725

164

55

121

244

59

7720

3

0

0

6

0

Table 2. Results of the chemical analysis of the soil from the water extraction of the GCC (Vyshnytsya river valley)

 

Conclusions

  1. Features of the building of and the water permeability of the sediments of the salt-bearing Precarpathian rocks form hydrogeological regimes of underground waters in the thickness of the GCC and of the brine-bearing horizon within the surface of the "salt mirror".
  2. Features of the hydrogeological groundwater regimes are one of the major factors in the formation of the modern structures of the GCC and the surface of the "salt mirror".
  3. Man-made interference that violates the natural groundwater regime in the thickness of the GCC in favorable conditions forms a sharp intensification of the karst processes within the surface of the "salt mirror".
  4. It is expected that there is the existence of relatively isolated hydraulic systems in a common aquifer in the GCC sediments. Their mode of operation is an essential factor in the development of the karst processes and is a reflection of the hydrogeological and geological conditions of the site location.

References

  1. Blajda R., Gorecki J. 2001. Influence of lithological and structural factors on the development of salt karst in the ‘‘Wieliczka’’ salt mine deposit (in Polish) Geologia: Kwartalnik Akademii Go´rniczo-Hutniczejim. Stanisława Staszica w Krakowie, 27, 329 – 340.
  2. Bruthans J., Jakub, Filippi M., Zeman O. 2000. Thickness of cap rock and other important factors affecting the morphogenesis of salt karst. Acta carsologica, 29/2, 51—64.
  3. Cedergren H.R. 1977. Seepage, Drainage, and Flow Nets. Wiley-Interscience, 465.
  4. Frumkin A. 1994. Hydrology and denudation rates of halite karst. Journal of Hydrology, 162, 171-189.
  5. Frumkin A. 2013. Treatise on Geomorphology. Salt Karst. Academic Press. Volume 6, 407-424.
  6. Gol'dberg V.M. Skvorcov N.P. 1986. Pronicaemost' i fil'tracija v glinah. Nedra, 161.
  7. Krzysztof B., Grzegorz C. 2009. Salt geology and mining traditions: Kalush and Stebnyk mines (Fore-Carpathian region, Ukraine). Geoturystyka, № 3 (18), 27-34.
  8. Mozer S.P., Kowaljow O.W., Thorikow I.J. 2010. Monitoring sostojanija vodozashhitnoj tolshhi na kalijnyh rudnikah. Górnictwo i geologia, Tom 5, 89-102.
  9. Pavliuk V. I. 2010. Vplyv pryrodno-tekhnohennykh faktoriv na formuvannya ekoloho-heolohichnykh umov v Peredkarpatti (na prykladi rodovyshcha kaliynykh soley «Stebnyk»). Stroytel'stvo y tekhnohennaya bezopasnost', 33-34, 256–265.
  10. Pavliuk V.I. 2011. Tekhnohenni faktory aktyvizatsiyi ekzohennykh protsesiv v mezhakh poshyrennya solyanykh vidkladiv Peredkarpattya. Stroytel'stvo y tekhnohennaya bezopasnost', 38, 88-95.
  11.  Stupnyts'kyy V.M., Zheksymbayev Yu.M., Fedchenko A.Y. i in. 1995. Otchet po pereotsenke zapasov kalyynykh soley Stebnytskoho mestorozhdenyya L'vovskoy oblasty. Fondy LHRE, L'viv, 377.
  12.  Whyatt J. Varley F. 2008. Catastrophic Failures of Underground Evaporite Mines. Proceedings of 27th International Conference on Ground Control in Mining. NIOSH, Spokane Research Laboratory, USA, 10.
  13.  Wolkersdorfer Ch. 2008. Water management at abandoned flooded underground mines. Springe, 435.

Zaharov V.F. 1964. Gidrogeologicheskie zadachi pri otkrytyh razrabotkah kalijnyh solej na Dombrovskom mestorozhdenii. Trudy vsesojuznogo NI instituta Galurgii, XLVI, 64-73.