002.60.Idrija

Idrija Mercury Heritage Management Center, Bazoviška 2, SI-5280 Idrija

Public

Republic of Slovenia

EŠD 185

Mine

The Idrija Mercury Mine (the pit) is an underground system, which was created by generations of miners through the 500 years of its operation, for exploiting mercury ore. It contains main levels, main shafts, blind shafts, sliding hole, tunnels, declines, mining fields and levels. The main level is a system of all tunnels, blind shafts, declines and mining fields on a certain level of the mine, which are followed from one level to another, into the depth. The main shafts connect the surface with the underground and are the main transport routes for the material, ore and miners. The blind shafts connect at least two main levels including levels and they never reach the surface. The sliding hole is a connection of the level with the lower main level. Depending on the geomechanical hardness of the rocks, the tunnels are supported with different support (wooden rectangular and trapeze, masonry, concrete, steel). The tunnels were not supported in the harder rocks. The declines are diagonal tunnels (on different angles) that connect the levels. The mining field consists of levels, which are connected with blind shafts and sliding hole. The level is a system of tunnels (including tracing works) and active stopes (usually in size of 2.5 × 2.5 m) on the same height, between two levels.

The Idrija Mine stretches in the area of mercury deposit in the northwest to southeast direction, it is 1500 m long, 400–600 m wide, 450 m deep. The Idrija pit encompassed 15 main levels, with its lowest point of 380 m (with the altitude -36 m). The length of the entire system of shafts and tunnels was around 700 km. The total length of open and maintained tunnels and shafts was at time of the interruption of works in the mine, in 1977, around 144 km and 5764 m after the end of the closing works.

Rock, wood, steel, concrete

According to the legend, the beginnings of the Idrija Mine go back to 1490, however, the oldest known written document is from 1493. The oldest preserved mine entrance is Anthony's shaft from 1500.

According to the legend, mercury was discovered by a barrel maker. At first, the Idrija ore deposit was exploited by private companies. In 1575, the mine was nationalised and up until 1918 (with the exception of the French administration, 1809–1913) it belonged directly to the power of the Habsburg/Austro-Hungarian Empire in Vienna. Between 1918 and 1943 it was managed by Italy (Monte Amiata), then by Germany for two years and after 1945 by Yugoslavia. After 1991 it belonged to the independent country of Slovenia. The Idrija Mercury Mine, as an economic entity, was liquidated in 2017 and deleted from the Business Register.

In the 500 years of mining, different managers of the Idrija Mercury Mine sent over 107,829 tons of mercury and 8,800 tons of cinnabar to the market. Through its history, it developed to the 15th level and had 9 open shafts in total. The mine was especially developed in periods, when production in Almadén couldn’t satisfy the demands of the American market and mercury was bought in Idrija. During the mining of the depths of the ore deposit, the miners developed the drift mining method of filling and excavating levels from bottom upwards (in use for more than 300 years). In the last period new level mining method, from the top down, was developed, which was used for obtaining carbon slate with native mercury. The mechanisation in the mine was introduced gradually yet constantly and it followed the technology achievements the entire time. In the 1960s, all phases of obtaining, transport and ore processing were updated. In 1977, regular ore mining was interrupted. In 1988, the long-term programme of closing the Idrija Mine was adopted. The last mercury in Idrija was obtained on 7 November 1995, then the furnaces in the smelting plant were permanently turned off.

The Idrija Mercury mine is being preserved, secured and presented as important mining heritage of Idrija with exceptional universal values. The consequences of more than 500 years of mining are long lasting. The preserved part of the pit is maintained by the public institution Idrija Mercury Heritage Management Center. Nowadays the shafts and tunnels are used as import and export transport routes for material and miners for the needs of maintaining the unfilled part of the pit and monitoring the influence area of Idrija Mine. The mine is inaccessible, filled with backfill material and submerged from the IV to the XV main levels. The only exception is the Francis' shaft, which is accessible to the IX main level, where the permanent pumping station of pit water is located. The unfilled part of the pit needs to be maintained permanently and the influence area of the Idrija mine needs to be monitored (geodetic, geomechanical and ecological measurements). The latter enables the protection of natural values and mining heritage. The part of the ore deposit above the IV main level will remain unsubmerged, therefore it will need to be constantly drained and maintained.

2357 Idrija – town, lot. no. 1281 (on the current place of the Church of the Holy Trinity).

Anthony's Main Road: 2357 Idrija – town, lot. no. 1460, 1461/3 (including with the corresponding tunnel system, blind shafts, declines to level I/17 of the Kropáč mining field), 1461/4; Francis' shaft: 2357 Idrija – town, building nos. 472 and 474, lot. no. 1168, including the main shaft – to the depth of the IX main level and the system of tunnels, blind shafts and declines including the III main level.

Between 1988 and 1992, the lower part of the pit in solid rocks, between the XI and the XV main levels, was submerged. In 2006, the submerging of the pit between the XV and the IX main levels ended. The top part of the mine (soft rocks), was hardened with the blown backfill of poor concrete (backfill of the open routes and shafts), with the injection of inaccessible areas and with producing support pillars in the ore bodies’ area. Within the pit, 14 important geological profiles are being preserved. The part of the pit with preserved elements of cultural heritage was arranged in the form of the museum presentation (Anthony's Main Road).

good

Performing regular maintenance services by the programme, including status control and preservation, security and presentation of the heritage.

- The Cultural Heritage Register of the Republic of Slovenia;
- Prevention of Effects of Mining in the Idrija Mercury Mine Act (the Official Gazette of the Independent Republic of Slovenia no. 37/87);
- Dolgoročni program postopnega, popolnega in trajnega zapiranja Rudnika živega srebra Idrija, 1988;
- Dopolnitvi dolgoročnega programa preprečevanja posledic rudarjenja v Rudniku živega srebra Idrija za obdobje 1996–2006, Government of the RS, 26.10.1995;
- ZVKDS Restavratorski center. Konservatorski načrt Idrija - Antonijev rov. Ljubljana, Idrija, 2010.

Mestni muzej Idrija

Miha Kosmač

2. 3. 2018

Never