The aim of the thesis is to describe how the Velenje Coal Mine deals with hydrogeological issues related to coil exploitation. In the first part of the thesis, I described the geology of the Velenje basin and how its hydrogeology relates to coal excavation. Three aquifers that get the most attention related to dewatering are described in detail. These aquifers are: aquifer above coal layer, which is further divided into three parts, triassic and aquifer in litotamnic limestone. In the second part of the thesis, I described piezometric well classes, which are used in the Velenje Coal Mine, as well as the necessary equipment for measuring underwater levels. The piezometric well network, which is in active exploitation area, is also described. In the last part of the thesis, I described how piezometric well Pt24a/17 was built due to the Pt24/83 piezometer breakdown. The laws that comply with the borehole construction are also described, as well as the technical procedure of the piezometric borehole construction. The borehole section and the geological structure of the area in which borehole was constructed is included in the appendix.