The iron ore tunnels

Stud Names:   2 lower, 1 middle and 1 upper iron ore tunnels  

Struck:      before 1500

Length:                    lower left cleat approx.             40 m                                                                                                                   

                 right lower stud                 crime                                                                                                      

                               middle stud                             crime                                                                                                      

                              upper stud                                43 m     

Altitude:               lower left stud                     1018 m                                                                                                            

                              right lower stud                  1024 m                                                                                                            

                              middle stud                             1040 m                                                                                                           

                              upper stud                                 1105 m      

1st story:

In historical times there was also ore mining in the Salzkammergut. However, for the most part it has remained at prospecting attempts and only in a few cases has there been short-term mining.

The ore deposits are exclusively sulphide ores such as pyrites, galena, chalcopyrite and sphalerite, which are accompanied by spar iron and brown iron ore and occur on the border between Werfen slate and dolomite.

On the Reinfalzalm above the Ischler Salzberg, iron mining in the so-called "Eisenarz" can be traced back to the 15th century. Around 1500, a certain Hans Gaisbrucker from Lauffen operated a mine for pyrite and brown iron ore including a vitriol smelter.

The remains of 4 tunnel mouths from iron mining can still be found in the area. The iron smelter was probably at the foot of the Salzberg just below the mouth of the Leopold tunnel. This is confirmed by slag residues that can be found in the ground in the area of the lower barn that was removed, the former impact room and up to the Auer well.

Vitriol was produced by roasting the pyrite, extracting the iron sulphide, which had been subject to a weathering process for several months, with water and boiling the solution until the blue-green vitriol crystals crystallized out. For this roasting and boiling process, 100 Rachel wood, which is around 700 m³, were used annually.

The Vitriolsudhütte was not far from the Matthias tunnel at the foot of the Sudhüttenwand. The 100 m³ heap can still be seen here today. The by-products of vitriol boiling are a strongly red-colored, earthy mass that was used as red chalk by masons and carpenters.

Dicklberger (1820) writes about the fate of the vitriol works at Reinfalz:  When in 1562 the exploration of the Ischler Salzberg was suggested by Hans Praunfalk, administrator in Aussee, the high directive was issued at the same time "to occupy the Salzberg, to visit the salt store, to diligently tend the forests on the Reinfalz, Mitterberg and in this area, and to completely stop all melting and boiling of the vitriol in these places in order not to tolerate any waste in the forests that will be necessary in the future for salt brewing.” Emperor Ferdinand I gave this order on September 25, 1562 and one year later the Ischl salt mine was approached.

This sealed the fate of the vitriol boiling plant.

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In the 1920s, two of the tunnels used to access the ore deposits were rediscovered by the Perneck miner Josef Hütter. According to old miners, the upper Eisenarz tunnel had been retrofitted in 1866 by the then mine manager August Aigner on his own initiative. The lower left iron ore tunnel was reconstructed 12 m by a group of speleologists from Linz at the end of the 1930s. In 2014, under the direction of Horst Feichtinger, a 7 m long new tunnel section was cleared in the mouth hole area of the upper iron ore tunnel.

In 1858 the same ore formation had been driven through when the tamper turned in the Maria Theresia horizon. The vertical distance between the Eisenarz and the Stampfer - Kehr is around 400 m.

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2. Location and geology:

The Eisenarze area is some 100 meters south of the Reinfalzalm (1026 m) on the Ischler Salzberg. Here, at the northern foot of the Sudhüttenwand, a ditch runs steeply in the forest in a SE direction. This graben is of tectonic origin and forms the boundary between limestone (Jurassic) in the NE and dolomite (Triassic) in the SW. The ditch extends to the crest of the ridge formed by the Sudhüttenwand and the Zwerchwand at about 1170 m above sea level.

Of the tunnels from the 16th century in the area of the ditch, only the upper iron ore tunnel, also known as the "Hütter-Stollen" after its rediscoverer (1920), is still conditionally passable today. From the other 3 you will only find Pingen and Halden, from the bottom left  Iron ore tunnel even still has the mouth hole. Above the Hütter tunnel, the mineralization is exposed on a cuirass. Otherwise there are no more outcrops during the day.

The mineralization can be found at the layer boundary between the Werfen slate and the Hallstatt dolomite. Sulphide ores include galena, sphalerite and pyrites. Calcite, dolomite and siderite (iron carbonate) form the carbonates and brown iron ore and quartz form the oxides.

Dolomite occupies the largest space in the ore pieces that can be found, calcite and siderite are rare. As a typical weathering mineral, brown iron stone is only found near the surface. The most conspicuous and predominant sulphide mineral is galena, which can be found up to     8 mm thick veins that are easily visible to the naked eye. Zinc blende can only be detected microscopically. You won't find pyrites at all. However, the existing vitriol boiler requires a pyrite deposit.

3. Cleats:

3.1. Lower Left Iron Ore Adit:

The lower left iron ore adit is at an altitude of 1018 m and is easy to find, as the damp and cold weather rising from the mouth of the adit forms a vapor strip that is visible from afar. Its entrance is frozen almost all year round. The tunnel was rebuilt at the end of the 1930s to a length of 12 m. Following that, he's been on the run since about 1985. The tunnel was originally passable over a length of about 30 m. Near its aft end was a shaft that had completely collapsed at a depth of about 15 m.

The entire tunnel including the shaft is in Jura limestone and there were no signs underground that it had ever hit another rock formation. The tailings pile consists largely of the same rock, but isolated pieces of Werfen slate can also be found. Since no mineralized rock is found, it can be concluded that the adit did not reach the mineralization at all.

3.2. Lower Right Iron Ore Adit:

The lower right vitriol tunnel, previously unknown in the specialist literature, was discovered during field inspections by F. Federspiel, H. Feichtinger and E. Ramsauer in the summer of 2016.

This tunnel is about 70 m south-west of the lower left vitriol tunnel at an altitude of 1024 m. The extensive slag heap is a good 28 m long at the crown. It is made up of fine-grained heaps containing plenty of ore. The size of the heap indicates what is probably the most extensive mine workings in the entire area. From the foot of the heap, the ore path, which is still clearly visible in sections, leads to the former vitriol sud hut near the Matthias tunnel.

3.3. Medium Iron Ore - Adits:

The middle iron ore tunnel is located at 1040 m above sea level in the lower part of the steeply rising ditch that begins in Eisenarz. Nothing remains of the tunnel mouth, but the Pinge and the heap are still clearly visible in the steeply sloping terrain. In addition to samples from the Hallstatt dolomite and the Werfen strata, numerous pieces with relatively rich galena mineralization can be found. This heap is the richest of the 4 tunnels.  

3.4. Upper Iron Ore – Adit:

The mouth of the upper Eisenerz - or Hütter - tunnel is at 1105 m above sea level and is very similar to a natural cave entrance. Only when you have crawled through the narrow entrance area do you come to a chamber-like extension, which still contains the remains of an old wooden structure. The ceiling height in the center of the hall is up to 3.5 m. On the side, a short tunnel leads past a rock pillar into a second chamber, which can also only be reached by crawling. The second working chamber runs parallel to the first chamber and is offset to the SE. A third mining area can be reached via a short, narrow gap. The approximately 4.5 m long and around 1.5 m high excavation chamber shows white sinter formations on the ceiling, which clearly stand out from the black rock coatings. The further continuation of the tunnel is likely to be closed by a breach. There are no longer any documents about the former extent of the tunnel.

While the first and second chambers are in the dolomite, pinching between the dolomite and the Werfen slate can be seen in the third chamber.

The 7.5 m long part of the tunnel, newly discovered by Horst Feichtinger in 2014, begins about 5 m behind the mouth hole area. With a width of 50 cm and a height of 90 cm, it runs in a straight line and evenly in the SE direction. Sintering and mineral efflorescence can be observed on the tunnel ceiling.

There are numerous black chunks on the heap of this tunnel, which only turn out to be ore-bearing after they have been smashed. The manganese-rich, black coating is the result of centuries of weathering on the rock. The mineralization here also consists mainly of galena.

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4. Vitriol - production and use:

Vitriols are minerals that belong to the salts of sulfuric acid (sulphates). The white zinc vitriol, the green iron vitriol and the blue copper vitriol are the most important representatives of this mineral class.

The term vitriol comes from Latin and is translated as "glass", based on the glass-like appearance of the crystals of vitriols.

Vitriols occur as oxidation products of sulphide ores. They are obtained by capturing leachates containing vitriol or by leaching weathered, oxidized metal ores. Georgius Agricola describes the production of vitriol in his work "Of the 12 Books of Metallurgy" published in 1556. Sulfur pyrites were leached out with hot water, the vitriol precipitated out of the solution and the resulting vitriol sludge was heated in a boiling furnace to evaporate the residual moisture.

Iron vitriol was primarily used to color leather, the so-called "blackening of leather". Iron vitriols were also used in fabric dyeing, for the production of dyes and ink, and as a disinfectant.

The representatives of the medieval alchemists saw more than just minerals behind the vitriole. For the alchemists, vitriols were the outer philosopher's stone, with the help of which the transformation of seemingly worthless materials into precious metals such as gold and silver should be possible. Despite centuries of research, the alchemists did not succeed in producing gold and silver with the vitriols.

Sources used:

Anton Dicklberger "Systematic history of the salt pans in Upper Austria", Volume I, Ischl 1817, transcription by Thomas Nussbaumer, Weitra 2018

Ludwig Antes and Siegfried Lapp "On the mineralization on the Reinfalzalm", Leoben 1966

Othmar Schauberger "Historical mining in the Salzkammergut", communication of the Austrian consortium for prehistory and early history, vol. 24, Vienna 1973

Johann Steiner "The traveling companion through Upper Austrian Switzerland", Linz 1820, reprint Gmunden 1981

Alfred Pichler "Lipplesgrabenstollenhütte", State Association for Speleology, Linz 2003

Wilhelm Freh "The iron mining in the country above the Enns", Linz 1949

Erich Haslinger "Ore deposits in the Salzkammergut", Vienna 1962

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