Assessment of post-mining terrain suitability for economic use

Abstract

Upper Silesian Coal Basin in Poland is subjected to underground mining for several hundreds of years. Due to intensive extraction, land surface has been widely transformed, causing a lot of mining damages. Of great importance is the issue of recovering the surface to its previous conditions after mining activity is finished. In specific conditions, a threat of mining damages may rest for several years after mine closure. In this paper, some chosen issues connected with assessment of postmining terrain suitability for economic use have been discussed. Two important elements of such threat have been described: determining the possibility of discontinuous deformations creation and the evaluation of active subsidence process duration. In the introductory part of the paper some theoretical base has been given. Next, the example of probability assessment of sinkhole creation has been presented, together with determination of subsidence process cease time. For determination of subsidence process duration, own empirical formulas have been utilized. They can be used in cases, when there is a lack of survey results from the area of interest.

Variation in shallow sandy loam porosity under the influence of shallow coal seam mining in north-west China

“…Compared with area around Line 1, this was less influenced previous mining work, resulting in the larger fractures with a shallower depth and smaller width. After formation of the subsidence basin, the surface ground soil gradually changed from a state of tension state to one of compression; therefore, the fractures in this area were produced in the preliminary stage of coal mining, and some fractures gradually became smaller or even closed under pressure in the later stages of mining, so the increase of porosity was slightly smaller than that along Line 1: because Line 2 lay within the disc-shaped subsidence central area, many fractures in the form of crazing, and with some fractures running parallel to the working face, will be produced in this area under the action of tension in the preliminary stages of coal mining (Strzałkowski and Ścigała, 2020; Wang et al., 2020). However, with the advance of mining face, the force on the surface points gradually changes from tension to compression.…”

Duration of the final phase of mining area deformation process in the conditions of Upper Silesia (Poland)

“…Mining exploitation and its cessation cause water level changes in the rock mass and formation of flooded areas (Didier 2009). From a practical point of view, a very important problem is knowing the duration of the deformation process (Strzałkowski and Ścigała 2020). This issue is of great importance, both in active and liquidated mines (Blachowski et al 2009).…”

“…The compliance of the formula with measurement results was the subject of research in the paper (Strzałkowski and Ścigała 2020). In formulas (1)-(2), the parameter of S. Knothe's theory appears -tgβ (Knothe 1953).…”

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

“…The transformation processes, ongoing around the world and especially in Europe towards a modern zero-carbon economy, are leading to a reduction in the fossil fuel exploitation in the mining industry. It should be taken into account that the termination of mining operations, in particular those of underground mines, does not entirely eliminate the problem of the impact of the excavations of an inactive mine on the rock mass and, in consequence, on the surface [1][2][3][4][5]. Although the problem of the continuous deformations related to the direct impact of the current exploitation disappears relatively quickly [6][7][8], one of the possible long-term dangers is the discontinuous deformation hazard, which may take the form of linear deformations (ground steps, fissures) [9,10] or surface deformations (sinkholes-Figure 1) [2,[11][12][13].…”

“…The problem is significant because this hazard, in the case of non-liquidated shallow workings, may exist for many decades after the end of exploitation [3,4,12].…”