A show mine is a mine that is accessible to visitors.
A mine, i.e. an industrial facility for the underground extraction of mineral commodities, has three operating phases: it may be open or running, or closed or it may be a working museum. Most mines are simply closed once they are no longer productive. For safety they are usually partially destroyed (filled in). However, many mines are at least partially accessible today to visitors.
In such cases they may be referred to as show mines or visitor mines if the focus is mainly on visiting the former mine, or mining museums if the mine only forms part of a museum. Most show mines have been set up in abandoned mines. In recent decades, however, they are often established immediately after mining ceases, creating some jobs funded at least partially by cultural tourism.