Backfilled principal transport shaft of the Idrija Mercury Mine, now preserved as a heritage complex with the Idrija Kamšt wooden water wheel, Scopoli's Memorial Garden, and renovated mine locomotives, forming part of the UNESCO World Heritage Site.
Jožefov jašek, opened in 1768, was the principal transport shaft of the Idrija Mercury Mine, the second largest mercury mine in the world. At 420 metres in depth, it was the only shaft to connect all fifteen levels of the mine, and its floor lies 33 metres below sea level. The shaft served for the transport of miners, ore, and materials throughout the productive life of the mine, and from 1956 onwards received all ore exports via a cableway to the smelting plant.
It was designated a cultural monument of national significance by decree in 2001 and forms part of the UNESCO World Heritage Site inscribed in 2012. In 2007 the shaft was backfilled to the surface. The surrounding complex preserves the winding tower, the winding and pumping machinery buildings, and the Idrija Kamšt of 1790 — the largest preserved wooden water wheel in Europe — which pumped mine water from a depth of 283 metres until 1948.
Adjacent to the shaft is Scopoli's Memorial Garden, and restored mine locomotives are exhibited in the vicinity.
Jožefov jašek was opened in 1768, during a period of high production in the Idrija Mercury Mine. Its function was the transport of miners and materials into the mine and the export of ore to the surface. At the time of its construction, it represented the primary production-era transport shaft of the operation. In the mid-nineteenth century the shaft was enlarged, and it continued in active use until the final cessation of ore extraction.
At 420 metres in depth, with its floor 33 metres below sea level, Jožefov jašek was the only shaft to connect all fifteen mining levels, making it the principal shaft of the entire mine complex. It was the largest ore export point in the system: ore was transported by rail initially and later by cableway from the shaft top to the smelting furnaces. Two parallel hoisting cages operated within the shaft, each moving in the opposite direction; from 1890 these were powered by a steam engine. In 1873 a steam engine for pumping water from the mine was also installed within the shaft complex; this was among the first such machines in use in the former Austro-Hungarian Empire.
The shaft was known for a period after the Second World War as jašek Delo (Work Shaft). In 1956 a cableway was constructed between the shaft head and the Separation Plant at the smelting complex, and from that point all ore export was redirected through Jožefov jašek, consolidating its role as the central ore export facility of the mine in its final decades of operation. After the mine's mercury extraction ceased in 1995, maintenance and closure works continued in the underground workings. In 2007 Jožefov jašek was backfilled to the surface.
In close relationship with the shaft, and constituting part of the same heritage complex, is the Idrija Kamšt. This large water-powered pumping device was installed in 1790, at the time when excavation works were beginning at Jožefov jašek, as part of the mine's exceptional late-eighteenth-century expansion. Driven by water from the Idrijca river conducted along the 3.5-kilometre channel known as the Rake, the Kamšt raised approximately 300 litres of mine water per minute from Level XI at a depth of 283 metres, through a three-stage piston pump system. Its overshot wooden drive wheel has a diameter of 13.6 metres and is considered the largest preserved wooden water wheel of its kind in Europe. The Kamšt operated continuously from 1790 until 1948, a period of 158 years. It is housed in a substantial masonry building on the left bank of the Idrijca at the point where the Rake channel enters the town.
Alongside the shaft complex, Scopoli's Memorial Garden was established to display plant species first described or discovered by botanists associated with the Idrija region, above all Joannes Antonius Scopoli, the mine's first physician and a natural scientist of European importance. Restored mine locomotives, formerly used for the transport of ore through the town, are also exhibited in the vicinity of the shaft.
Jožefov jašek was designated a cultural monument of national significance by the Decree on the Declaration of Technical Heritage in Idrija and its Surroundings as Cultural Monuments of National Significance, first issued in 2001 (Uradni list RS, št. 66/2001) with subsequent amendments. The shaft and associated structures, including the Kamšt, form part of the UNESCO World Heritage Site 'Heritage of Mercury. Almadén and Idrija', inscribed on 30 June 2012. The surface complex, comprising the shaft tower with its characteristic mining-hammer emblem, winding structures, and the Kamšt building, remains accessible to visitors as part of the Idrija mining heritage trail along the Rake.