A roof fall hazard is still one of the major threats in the underground mining industry. Each such type of event always brings great risk to miners and causes serious interruptions in the process of rock excavation. In general, the possibility of roof fall hazard occurrence is directly related to the local geology, the presence of horizontal stresses as well as the type of excavation method and the efficacy of the utilized roof support. Due to the complexity of this process, it is important to continuously evaluate the roof fall risk, especially in long life-time places where a mining crew is often present. Within this article, a detailed review of the current methods of monitoring and evaluating roof fall risk was presented. Based on the extensive literature survey, different types of devices were described, and their advantages and disadvantages were pointed out. Furthermore, new trends in the area of roof fall risk monitoring were described and discussed.

Roof falls are currently one of the most dangerous threats associated with underground mining at great depth. Every occurrence of such an event poses a significant risk to the mining crew and disturbs the continuity of the mining process, which clearly affects the economy of the exploitation process. The development of a reliable monitoring system may significantly reduce the impact of eventual roof failure and will have a positive effect on the sustainability of the extraction process. Within this research study, a prototype of an instrumented rock bolt developed for continuous stress measurement is presented. The procedure of a 4-groove multilevel instrumented rock bolt is described and the calibration process is shown. Then, preliminary results of long-term in situ monitoring are presented. Based on the continuous monitoring of stress distribution within immediate roof strata, it was concluded that the developed instrumented rock bolt provides reliable results and is a very useful device, ensuring the possibility of early warning for miners about increasing roof fall risk.

Proper monitoring of seismic risk and reliable evaluation of destress blasting efficiency requires a well-developed seismic network surrounding the analyzed area. Unfortunately, the construction of a dense seismic monitoring system using standard types of seismometers and accelerometers is associated with high costs of seismic network development and maintenance. Significant improvements in this regard may be potentially achieved by replacing expensive monitoring devices with other cost-effective sensors such as MEMS-based accelerometers. Nevertheless, this topic has not been sufficiently investigated yet, and the usefulness of such devices for monitoring seismicity in deep underground mines has not been recognized. The goal of this paper was to perform preliminary measurements of blasting-induced seismicity in the near-wave field with the use of a single three-axial MEMS-based accelerometer and three uniaxial seismometers. The collected seismic records induced by multi-face blasting were compared in time and frequency domains. In the time domain, the values of 3D peak motion plots were analyzed, and the possibility of identification of subsequent delay times in recorded waveforms was investigated. In the case of frequency distribution, the Power Spectrum Density plots were calculated and compared. The results of the analysis proved that MEMS-based accelerometers provide reliable results and may be successfully implemented for regular use in underground seismic monitoring systems.

Underground mines are a vital part of the European raw material industry. The subsurface mining process is related to the large-scale development of underground structures like tunnels, chambers, workings, etc. These structures are abandoned or liquidated during the process of exploitation or after the termination of works. Still, due to the unique environment, post-mining facilities may be adopted for different purposes. There are few examples of implementations of this capacity in practical terms such as underground laboratories (ULs), energy storages, landfills of dangerous wastes, or food production plants. Unfortunately, the unique environment offered by underground space is also related to the occurrence of exceptional hazards, like seismicity and ground control problems, gases, floods, the lack of natural ventilation, and high temperatures. This results in low interest in investing in such facilities. Within this paper, some ways to repurpose underground mines have been presented, and possible challenges that need to be faced have been described. An extensive database of threats to post-mining repurposing and ways to mitigate them has been prepared based on surveys and interviews conducted with representatives of currently existing Uls and mining companies and a literature review. Finally, this manuscript provides a general look at post-mining infrastructure in Europe’s current situation and in the future.