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.