Bezpieczeństwo Pracy i Ochrona Środowiska w Górnictwie Number 09/2018

Prediction of the rock masses deformations is very important element while designing tunnels. The paper presents a series of numerical simulations of flysch rock mass behaviour in the tunnel excavation region. The change of state of stress and displacement as a result of the excavation has been analysed. The Abaqus software and educational RS2 software uses the Finite Element Method was used for the calculations. Multi-variant analysis was performed using the Coulomb-Mohr hypothesis. The obtained results have been presented in the form of graphs and maps of stresses and displacements. The presented results of numerical calculations shows the influence of the change in the angle of  the discontinuity inclination of the rock mass and their mechanical properties (i.e. normal and tangential stiffness) on the state of stress and strain in the tunnel area. Presented simulations allow engineers to visualize  the potentially greatest threats and provide a quick protective response.

The article presents the history of the formation of mining supervision in Lower Silesia, an institution which has been inseparably connected with the development of mining in the region, from its establishment to the modern times. The Regional Mining Authority (OUG) in Wrocław was founded in 1946, and was initially seated in Żary. After moving to Wrocław in 1953, the Authority took charge of the Szczecin region, and, partially, of the Gdańsk, Poznań and Wrocław regions. Subsequent administrative reforms brought upon changes to the structure and local competence of mining supervision. Starting with 1955, Lower Silesia was supervised by OUG Wrocław and OUG Wałbrzych. The establishment and construction of coper ore mines was a critical moment for the Regional Mining Authority (OUG) in Wrocław. This was a great challenge, since the deposits discovered were inaccessible and required the application of a complex shaft dredging technology. The tasks and shape of mining supervision was significantly changed by subsequent administrative reforms (1975, 1999), the inclusion of OUG Wałbrzych in the structures of OUG Wrocław (2002), Poland’s accession to the European Union (2004) and the inclusion of common mines under administrative control of the mining supervision authority (2012). Today, the Regional Mining Authority in Wrocław is a team of experts, each specializing in a different field. Their main task is to improve the work safety in mining facilities throughout Lower Silesia. The 70^th anniversary, embodied by the fabulous Gwaruś gnome and commemorated by a celebratory medal, is an expression of gratitude to all those whose work has contributed to the development of the regional mining authority throughout the years.

-in faces at the height of up to 3.0 m. Face 9b-S situated in the northern part of the field was launched first. Since an endogenous fire broke out in the mined deposits in liquidation, the face deposits and a part of the pits used for the next face were embanked, and the field was reassigned to two other fields: 8b-S and 10b-S. Based on the experiences gathered for face 9b-S, a series of additional solutions was designed for face 8b-S of approx. 160 m in total length. Their goal was to limit any imminent natural threats, with primary focus on fire threat. However, since the beginning of its mining, it was methane threat that has proven dominant for face 8b-S. For this reason, all mining operations on the wall needed to be stopped and additional preventive measures were applied. These consisted in restricting access to the face, increasing methane exhaust capacities, introducing auxiliary ventilation devices in the vicinity of its intersection with the ventilation drift, and intensifying the sludging of mining batches with an ash and water mix.  These measures have limited the prevalent methane threat. The next face (2b-S) of approximately 240 m in total length was aired using the “U” method in the initial course. Based on earlier experiences, additional drift pits were created in its course. After about 280 m, this enabled the face to be mined and aired using the “Y” method.

In consequence, the methods of mining the 3^rd layer in deposit 510 in field S was changed in that the lengths of successive faces were reduced (the number of faces was increased for the field from the planned 9 to 13) and the overlaying pits were demethanized (inclined demethanization drifts) in deposit 501. Thanks to the application of this demethanization method, the methane threat was significantly reduced on the next face: 12b-S, thus contributing to its safer and more effective mining. At the turn of 2016 and 2017, mining was commenced for deposit 510 on face 3b-S in the southern part of field S. However, this operation was grossly affected by the imminent rick burst threat. Despite the preventive measures applied (restricted daily progress, shock and loosening bursts in the deposits, torpedo bursts targeted at the ceiling), high-energy rock mass vibrations impacted the near-face pit, rapidly increasing the carbon oxide contents in the vicinity of the face after one of the shocks, forcing the construction insulation of the face area in the form of anti-explosive plugs.

This paper presents the list of tasks and responsibilities of the safety service concerning opinions and commentaries on the quality of safety trainings courses and the appropriate legal permissions. The main task of safety service in Poland is to consult the safety regulations with employees, cooperate in organization of safety trainings, popularize safety issues and ergonomics in the underground workplace. With reference to recent discussions concerning the quality of safety trainings and qualifications of trainers, the following problem should be considered: are workers, who perform safety service well educated and have responsibilities and legal permission to do their duties?

As of the beginning of 2002, peat harvesting has been regulated by the amended provisions of the Geological and mining law. The new legal reality was unfamiliar for the entire peat harvesting industry. At the same time, the milling technique used in harvesting high-deposit peat, characteristic for this industry only (its application conditions, equipment and devices used) were a novelty for the mining supervision staff. High-deposit peat is extracted using the so-called milling technique. Preparatory and uncovering works consist in logging all trees and cutting all underbrush and removing the topsoil. After that, the deposit is drained using dedicated drainage ditches routed among peat harvesting fields. The process of extracting peat is arbitrarily divided into four stages / operations: milling, drying, preparation for harvesting and peat harvesting. At the milling stage, a peat layer of about 15-40 mm is separated from the deposit. At the stage of drying, the overall humidity of the peat is lowered to approx. 50-60% or approx. 40-45%. Preparation for harvesting consists in collecting the peat on small piles (so-called stacks) surrounding the extraction fields. Dried peat is collected using a machine with scooping baskets or by sucking peat into a tank.  Peat harvesting using the milling technique involves certain hazards, especially the fire hazard.