Underground and opencast mining adversely affects the surrounding environment. This process may continue even decades after the end of actual mineral extraction. One of the most significant effects of ceased mining are secondary deformations. Safe, new development of post-mining areas requires reliable information on potential deformation risk zones, which may be difficult to obtain due to a lack of necessary data. This study aimed to investigate and understand the secondary deformation processes in the underground mining area of the former “Babina” lignite mine, located in the unique glaciotectonic environment of the Muskau Arch, in western Poland. A combination of GIS-based historical mapping, geophysical 2D/3D microgravimetry, and Electrical Resistivity Tomography (ERT) measurements allowed the identification of subsidence-prone areas and the determination of potential factors of sinkhole development. The latter are associated with anthropogenic transformation of rock mass and hydrogeological conditions, by shallow underground mining. The results confirmed that multi-level mining of coal deposits in complex and complicated glaciotectonic conditions cause discontinuous deformations, and may be hazardous as long as 50 years after the end of mining operations.

Photogrammetry is one of the contactless geodetic techniques that provide reliable information about objects and their surface properties. Traditional photogrammetric methods require specialized equipment, such as metric cameras, which are very expensive and difficult to access, and the processing of the data obtained from them requires a significant investment of time. An alternative to this solution are generally available non-metric cameras, which can replace professional photogrammetric devices. Currently, consumer-grade digital cameras are enjoying the increase of popularity among photogrammeters thanks to the interchangeable lenses, good image sensor quality and the ability to manually set all camera parameters. However, due to the high costs of purchasing and maintaining such equipment, mobile phone digital cameras are increasingly used, the parameters of which are beginning to match many professional digital SLRs. The newest smartphones are also waterproof, so they can have potential applications in underwater photogrammetry. This article presents the possibilities of using mobile phone cameras in close-range photogrammetry and shows the beginning of research on the use of smartphones in underwater photogrammetry. Three-dimensional models of the gear wheel were made on the basis of photos obtained in two media: in the air and underwater. The two point clouds were then compared, obtaining an average distance difference of ±0,3 mm.

The correct estimation of earth pressure is important for the design of earth retaining structures and depends, among others, on the surface morphology of retaining structures. The diaphragm wall created as a protection of a deep excavation located in an urbanized area was selected as a research object. Terrestrial Laser Scanning (TLS) was used for the investigation of the unique surface (in real-world dimension) obtained by tremieying the concrete in different soil layers. An original and innovative procedure for concrete surface description was developed, which includes steps from the TLS measurement to the determination of the roughness parameters. The tested samples from anthropogenic soil, medium sand, and sandy gravel, map the real diaphragm wall surface. The surface roughness parameters in different soil layers were compared with the reference surface obtained by cast against steel formwork. The following parameters: Sa, Sdr, and Vmc are indicated as being the most useful in numerical description of the concrete surface type and in allowing the determination of the soil surface friction. The novelty of this study is the estimation of the parameter δ (friction angle between the retaining wall surface and the soil), which is, among others, a function of the wall surface roughness. The influence of the type of surface on earth pressure are generally recognized in laboratory tests. Based on the estimated in situ values of δ, the more reliable active and passive pressure coefficients Ka, Kp were calculated for the tested soil layers. The conducted study has a practical significance for designing of retaining construction and makes progress in determination of surface roughness required in Eurocode 7.