Bezpieczeństwo Pracy i Ochrona Środowiska w Górnictwie Number 02/2021

One of the most common consequences of pumping water from groundwater reservoirs includes land surface movements. The main cause of this phenomenon is the excess use of groundwater resources, which leads to the development of continuous deformations. In Poland, the reduction of rock mass due to drainage is most often connected with mining operations. Land surface movements caused by rock layer drainage may range from several dozen millimetres to even several metres. The scope of this phenomenon is usually extensive and, in many cases, difficult to define clearly. Many methods are used to model land surface movements caused by drainage. These types of analyses and simulations are generally based on theoretical methods, which make it possible to adopt a holistic approach to the issue of geomechanical rock mass transformation due to rock mass drainage and to obtain very good modelling results. However, they are often inefficient, especially when it comes to time-consuming calculations. Therefore, the necessity of carrying out further research in order to allow aquifer compaction to be modelled more efficiently is indicated. At present, particular attention is paid to research on the use of InSAR and artificial intelligence for this purpose. The paper presents an overview of models used to predict land surface movements caused by rock layer drainage.

The search of dammed excavations has always posed a great threat to mine workers due to the presence of an unbreathable atmosphere, high temperature, and humidity in the area excluded from the ventilation system. As specified in legal regulations, such works should be carried out by rescuers during rescue operations. Due to heavy restrictions and costs of "official" rescue operations in hard coal mines, unauthorised entries behind the dams, referred to as "silent operations", used to be carried out. Collective fatal accidents in three mines that occurred during such works are described, pointing out that the workers injured during excavation searches were not protected by rescue teams and doctors and, due to harsh microclimate conditions, may have suffered heat stroke. After the first of the described accidents, the principle adopted was that the search of previously dammed excavation is to be carried out only when an air duct is also installed. In addition, rescuers were equipped with cool vests, while inhaled air coolers were installed in W-70 apparatuses. Mine ventilation and rescue teams were also equipped with individual instruments for continuous gas content measurement and thermohygrometers. Criteria and rules for employing rescuers in harsh microclimate conditions were also verified and included in the current regulations.