This article presents a case study that demonstrates the applicability of unmanned aerial vehicle (UAV) photogrammetric data to land surface deformation monitoring in areas affected by underground mining. The results presented include data from two objects located in the Upper Silesian Coal Basin in Poland. The limits of coordinate and displacement accuracy are determined by comparing UAV-derived photogrammetric products to reference data. Vertical displacements are determined based on differences between digital surface models created using UAV imagery from several measurement series. Interpretation problems related to vegetation growth on the terrain surface that significantly affect vertical displacement error are pointed out. Horizontal displacements are determined based on points of observation lines established in the field for monitoring purposes, as well as based on scattered situational details. The use of this type of processing is limited by the need for unambiguous situational details with clear contours. Such details are easy to find in urbanized areas but difficult to find in fields and meadows. In addition, various types of discontinuous deformations are detected and their development over time is presented. The results are compared to forecasted land deformations. As a result of the data processing, it has been estimated that the accuracy of the determination of XY coordinates and the horizontal displacements (RMS) in best case scenario is on the level of 1.5–2 GSD, and about 2–3 GSD for heights and subsidence.
Seismic phenomena threaten land-based buildings, structures, and infrastructure and can transform land topography. There are two basic types of seismic phenomena, namely, tectonic and anthropogenic, which differ mainly in epicenter depth, surface impact range, and magnitude (energy). This article shows how a land surface was changed by a series of seven rock mass tremors of magnitude ML = 2.3–2.6 in March–May 2017. Their immediate cause was the “momentary” acceleration of void clamping, which was activated by local and short-term seismic phenomena caused by human activity. The induced seismic events resulted from the geological structure of the rock mass, which in the specific region of examination was classified as being highly prone to mining tremors. The authors focused on describing vertical surface displacements in the Upper Silesian Coal Basin in the south of Poland. The surface deformations were identified using DInSAR technology, which allows quasi-continuous monitoring of large areas of land surface. The present research used freely available data from the Copernicus Program and seismic data from the European Plate Observing System.
Excavation of the two bedded deposits of mineral resources in a small vertical distance may cause additional increased mining risks (rock mass deformation, rock bursts and mining tremors, threat to land surface). This paper considers the impact of excavation of the copper ore deposit on the bed of rock salt located above it and the opposite, in terms of displacements and deformations. We used the theoretical models of processes verified by previous in situ observations in the mines of the Legnica-Głogów Copper Mining District. We analysed the potential for reducing the risks, among others, through coordination of mining works.
In the case of locating two bedded deposits of different mineral resources in a small vertical distance, additional or increased mining hazards can occur (deformations of the rock mass, crumps and mining shocks, hazards to the land surface). This paper has thoroughly examined the impact of exploitation of the lower-located deposit of copper ore on the higher-located deposit of salt as well as the reverse situation as regards the dynamic phenomena, being the greatest lithospheric hazard in LGOM. At the same time theoretical models of processes were applied, verified by previous observations in situ in mines of Legnica-Głogów Copper Belt.
As a result of mining of deposits of mineral raw materials, spaces are formed in the rock mass, which get partially filled with roof rocks or by the backfill, most often sand. However, some voids remain in the rock mass, and can be used as a place to locate waste. The thesis analyses systems and operating conditions of mining deposits, in terms of the possible existence of spaces for filling in the LGOM mines. It was determined that the most probable option is to use goafs after mining the ore with a thickness of over 3 m in the last 5 years, with the systems of roof deflection and their partial lifting. Quantitative evaluation of the voids is based on the comparison of the subsidence over the extraction field and the volume of the extracted deposit. It has been proved that the existing voids provide the possibility of locating approximately 8 million m3 of waste in goafs. It is highly possible to locate further 11 million m3 of waste after obtaining positive results of the practical location of them and gaining relevant experience. The goafs after mining with hydraulic filling, goafs in the deposit of the thickness of up to 2 m and mined more than 20 years ago were recognized as useless for locating waste.
Buildings located in mining terrain, in addition to typical utility and environmental loads, take on the impacts in the form of ground surface deformation and mining tremors, which can adversely affect their technical condition. In these terrains, activities are carried out to prevent possible adverse impacts of mining on buildings. One of such activities is planning at the project stage for preventive protections of building structures against mining impacts and their implementation during the construction stage. The paper presents the results of an analysis of the cost of preventive structural protections performed in a group of single-family masonry residential buildings. For each building, we determined the replacement value and calculated the average share of the cost of preventive protections in the construction costs. Based on the difference in the course of technical wear between protected and unprotected buildings, a period of less than 26 years was determined during which the expenditures spent on the buildings’ preventive protections are compensated by their lower technical wear. Over the subsequent useful life, owners of protected buildings receive measurable benefits in the form of lower technical wear of the buildings, and thus higher replacement value, as well as lower costs of repairs or renovations. The proposed approach can be applied to other operations concerning buildings or other fields of engineering to assess economic efficiency.