Assessment of Sinkhole Hazard in the Area of Shallow Mining Workings Using Electrical Resistivity Tomography

This paper presents the results of investigating shallow rock mass layers with the use of electrical resistivity tomography. The aim of the study was to assess the condition of near-surface rock mass layers located above shallow mining workings of a historical mine in view of the possibility of the occurrence of loose zones or possible voids that could pose a sinkhole hazard for the surface. The study was carried out under the conditions of the “Sztygarka” Training Mine and Museum in Dąbrowa Górnicza City (Upper Silesian Coal Basin, Poland), where discontinuous surface deformations occurred in the past in the form of sinkholes. The study and its interpretation indicate the existence of a sinkhole hazard due to the ongoing processes of the transformation of the near-surface rock mass layers above the shallow workings of a historical mine.

Property Risk Assessment of Sinkhole Hazard in Louisiana, U.S.A

Sinkholes (or dolines) are an often-overlooked environmental hazard. The processes that lead to their formation are slow and insidious, which encourage a lack of awareness or concern for the potential danger, until the sudden, climactic formation leads to unexpected property damage and possibly human casualties. This research identifies the risk to residential properties to the sinkhole hazard, using Louisiana, United States as a case study. Risk is defined as the product of the hazard intensity and the loss to structure and contents within the building resulting from the hazard-related disaster. Results suggest that risk is highly scale-dependent. Although the risk due to sinkholes is small on a per capita basis statewide, especially when compared to the per capita risk of other natural hazards, the property risk for census tracts or census blocks partially or completely overlying a salt dome is substantial. At finer scales, Terrebonne Parish, in coastal southeastern Louisiana, has the greatest concentration of salt domes, while Madison Parish, which is east of Monroe, has the highest percentage of area at risk for sinkhole formation, and St. Mary Parish—immediately west of Terrebonne—has the greatest risk of property loss. An Acadia Parish census tract has the maximum annual property losses in 2050 projected at $40,047 (2010$), and the highest projected annual per building ($43) and per capita ($18) property loss are in the same St. Mary Parish census tract. At the census block level, maximum annual property loss ($7,040) is projected for a census block within Cameron Parish, with maximum annual per building loss ($85 within West Baton Rouge Parish), and maximum per capita annual property loss ($120 within Plaquemines Parish). The method presented in this paper is developed generally, allowing application for risk assessment in other locations. The results generated by the methodology are important to local, state, and national emergency management efforts. Further, the general public of Louisiana, and other areas where the developed method is applied, may benefit by considering sinkhole risk when purchasing, remodeling, and insuring a property, including as a basis of comparison to the risk from other types of hazard.

Surface Deformations Resulting from Abandoned Mining Excavations

The occurrence of surface discontinuous deformations in post-mining areas is currently a significant and important problem, due to both the frequency of their occurrence and the threat they pose to public safety. This paper presents the results of research concerning the possibility of sinkhole formation in the areas of abandoned mining excavations. For the purpose of assessing the condition of the rock mass disturbed by the existence of numerous mining excavations, electrical resistivity tomography investigations were carried out for the selected area where mining was undertaken in the past at shallow depths and many underground workings accessing the deposit exist. The sinkhole hazard was also analysed theoretically with a new original model based on the solution of A. Sałustowicz’s pressure arch theory.

Sinkhole Hazard Caused by Inactive Mining Shafts as Illustrated by a Selected Example

Loss of stability of shafts liquidated in the past is a frequent cause of sinkhole creation on the surface. This manuscript presents such a case study. The sinkhole was created shortly after intense rainfall, so it can be assumed that displacement of the rock material in the shaft took place, i.e. the phenomenon of suffusion. One of the research aims was to confirm the assumption about the displacement of rock material filling the shaft on the basis of selected methods of sinking forecasting. Ex post forecast sinkhole creation was conducted using two methods (Bell and finite element method). It was assumed that the material filling the shaft lowered itself to a height determined on the basis of the sinkhole and shaft dimensions. Both methods gave the same results, consistent with the literature . The manuscript also presents a short overview of technologies used for decommissioning shafts and assesses their effectiveness in terms of preventing sinkhole creation. These methods have been used since the nineteenth century until present times. Considering the suffusion phenomenon, the paper proposes a way to drain rainwater from the shaft area, which was another purpose of the work. The necessity to find and verify the ways to secure decommissioned shafts from water is indicated as an important future direction of research.

Morphology and depositional setting of the sinkhole affected Armala area, Kaski District, western-central Nepal

Armala area of the Kaski District of Nepal is a flat valley of the Kali Khola, which is suffering from sinkhole hazard since 2013. Alarge volume of gravels was transported by the Seti River originated from the Annapurna Range, and the Pokhara Valley and its peripheral regions like the Armala Valley were filled up. The filled-up material in the Armala Valley is calcareous clayey silt with very few gravels. The deposit along the Armala Valley is undergoing subsurface erosion due to flow of subsurface water resulting the formation of subsurface caves and ultimate formation of sinkholes. Present study was concerned about the landform and morphological setting of the area, sediment characteristics and depositional environment of the sinkhole-affected Armala area. Five types of depositional sequences have been identified in the study area; their depositional history and depositional environment also have been interpreted on the basis of the sediment properties as fluvio-lacustrine type. Landform and depositional setting along the study area also seem to influence the sinkhole formation mechanism.

Sinkhole hazard in the post-mining area of Old Copper District, Lower Silesia, Poland

This study discusses the occurrence of sinkholes and the removal of their effects in the territory of the Old Copper District in the municipality of Lubków, Warta Bolesławiecka, located in the voivodeship of Lower Silesia. Three sinkholes appeared more than 25 years after mining activities ceased with the closure of the “Konrad” Mine of KGHM Polska Miedź S.A. The sinkholes appeared in the former mining areas in the years 2017 - 2018: the first in the area of the Lubichów III shaft located in the municipality of Lubków - the downcast and transport shaft of the "Lubichów" and "Konrad" mines; the second in the area of Lubichów IVa in Lubków - the ventilation shaft of the "Lubichów" and "Konrad" mines; and the third in the area of the Lubichów IVa shaft - in the village of Lubków. The “Lubin” Mine of KGHM Polska Miedź S.A. commissioned development of projects to mitigate the risk and to secure the areas and remove the dangers.

The Role of Earth Observation, with a Focus on SAR Interferometry, for Sinkhole Hazard Assessment

Sinkholes are global phenomena with significant consequences on the natural- and built environment. Significant efforts have been devoted to the assessment of sinkhole hazards to predict the spatial and temporal occurrence of future sinkholes as well as to detect small-scale deformation prior to collapse. Sinkhole hazard maps are created by considering the distribution of past sinkholes in conjunction with their geomorphic features, controlling conditions and triggering mechanisms. Quantitative risk assessment then involves the statistical analysis of sinkhole events in relation to these conditions with the aim of identifying high risk areas. Remote sensing techniques contribute to the field of sinkhole hazard assessment by providing tools for the population of sinkhole inventories and lend themselves to the monitoring of precursory deformation prior to sinkhole development. In this paper, we outline the background to sinkhole formation and sinkhole hazard assessment. We provide a review of earth observation techniques, both for the compilation of sinkhole inventories as well as the monitoring of precursors to sinkhole development. We discuss the advantages and limitations of these approaches and conclude by highlighting the potential role of radar interferometry in the early detection of sinkhole-induced instability resulting in a potential decrease in the risk to human lives and infrastructure by enabling proactive remediation.