Hg Smelting Plant Museum

The Hg Smelting Plant Museum in Idrija is one of the most compelling industrial heritage sites in Slovenia, offering a close look at how mercury was processed in a town that supplied the world for centuries. The plant operated from the 18th century onward, and its preserved machinery shows the evolution from early manual techniques to complex thermal systems designed to extract mercury from cinnabar ore. Inside, visitors can explore the roasting furnaces, where ore was heated to release mercury vapour. These massive brick structures are among the museum’s most striking features, revealing the scale and intensity of smelting work. Equally fascinating is the condensation system, a network of pipes and cooling chambers where mercury droplets were collected—an ingenious solution that allowed Idrija to become a global centre of production. The museum also presents protective gear, measuring instruments, and archival photographs that illustrate the dangers of mercury exposure and the strict procedures miners and smelters followed. A highlight is the demonstration of how liquid mercury was stored and transported, showing its unusual weight and behaviour.