11 b The stone main channel "Between the mountains"
The Ischl salt dome has the shape of a flat wedge that tapers upwards and inclines towards the north, which strikes from east to west. In the area of the Reinfalzalm, the salt-bearing layers bite out to the surface. As the wedge-shaped deposit is tapered upwards, the upper adits were a major disappointment. The north-south extent of the salt deposit was only 40 m, the east-west strike around 250 m.
In this small salt deposit, the leach works quickly reached the overburden and thus water-bearing limestone layers. The penetration of so-called scour water repeatedly led to extensive factory collapses, which, due to the small thickness of the overlying layers of cover, continued into the day area of the Reinfalzalm and into the area "between the mountains" south of the Reinfalzalm. The surface water collected in the resulting caverns ("Pingen") and penetrated unhindered into the pit areas with sometimes devastating consequences.
As early as 1600, the need to collect surface water in wooden gutters in order to quickly drain it away from the collapsed areas of the Reinfalzalm and thus prevent further damage in mining was recognized.
In 1738 there was a catastrophic flood in the Streybel and Seitzen weir in the Frauenholz tunnel. For this reason, an inspection was held on April 16, 1738, at which it was decided to dig a new water tunnel (middle water tunnel) in the Reinfalzalm area to search for the waste water and to extend the existing drainage system. However, the hoped-for success did not materialize, since fresh water entered the Frauenholz tunnel unhindered until the construction of a water pit in the Lipplesgraben tunnel in 1769. This water scour was successfully driven underground into the almost 15 m deep Pinge, which is still clearly visible in the area today, to drain off the water. The drainage system at the Reinfalz was expanded in 1746 and 1741 in order to be able to safely drain the harmful surface water above the salt storage.
In 1769 Hofkammerrat Gigant found the surface water that had penetrated the Frauenholz tunnel well summarized in the Lipplesgraben tunnel. To protect the salt storage against the sedimentation of rainwater, the surface area was already criss-crossed by a dense network of drainage ditches and side channels, the ongoing maintenance of which, however, required great expense. In order to reduce this, the Verwesamt decided in 1795 to give up that part of the drainage system that ran over lettuce, i.e. water-impermeable ground, and where there was no longer any fear of the further penetration of surface water.
A major repair of the then already 1,125 fathoms (2,133.54 m) long main and side gutter system, which was partly made of batten and partly consisted of wooden gutters, was carried out in the years 1830 - 1831.
In 1843 there were again extensive factory collapses at the Ischler Salzberg. The Erlach works in the Frauenholz tunnel and the Mohr and Freund works in the Elisabeth tunnel collapsed, allowing large amounts of polluted water to penetrate from the surface layers. In addition to the excavation of the Keel rubble in the Amalia tunnel for direct underground exploration of the waterways, it was also decided to further expand the water channels on the Reinfalzalm above.
In order to reduce the repair work and the associated costs for the extensive water channel, this was made from hand-hewn limestone blocks instead of wood from 1840 when repair work was required. The standard cross-section of the cuboid drainage system was set at 20 cm deep and 45 cm wide. The first cuboid drainage system was built between 1840 and 1850 over a length of 92 fathoms (174.48 m) from the Reinfalzanger to the Niederes Wasserstollen.
In 1892, the Imperial and Royal Ministry of Finance approved the construction of a workers' accommodation hut made of stone masonry as a replacement for the wooden tunnel hut built in 1567 on the Lipplesgraben tunnel.
At the end of 1905, the total length of the drainage system was 1,103.00 m. Of this, 201.30 m were made of wood and 901.70 m of ashlar.
From 1913, prefabricated concrete elements began to be used instead of the laboriously hand-made ashlar blocks. The so-called "cement channels" with two different standard profiles (45 or 35 cm wide and 20 cm deep) were manufactured in the Perneck tube works not far from the Leopold tunnel. In the years 1913, 1917 - 1918 and 1918 - 1919 another 135 m of the wooden gutter were replaced by cement gutters.
From 1924, as a result of renewed factory collapses, extensive subsidence and landslides occurred in the south-eastern area of the Reinfalzalm. By 1927, an area of more than 9,500 m² was in motion. This also affected the stone main drainage system, which was destroyed over a length of around 150 m. As a replacement, two inexpensive wooden gutters were built parallel to the destroyed main gutter.
Until 1950, the "Stone and wooden water channel between the mountains" was repaired annually by the Ischl salt mine. The construction crew lived in the tunnel hut near the Lipplesgraben tunnel. After the completion of the maintenance work on the water channel, the tunnel hut was leased from the salt pans to the Upper Austrian Cave Researchers' Association.
In the course of the construction of a forest path "Between the Mountains" at the beginning of the 1970s, large areas of the stone main drainage system were destroyed or covered over. In May/June 2020, members of the IGM were able to uncover this mining historical monument, which is important for the Ischler Salzberg, over a length of approx. 100 m with considerable effort and only by hand.
Ischl home club "Bad Ischl home book 2004", Bad Ischl 2004
Anton Schauenstein, "Denkbuch des Österreichischen Berg- und Hüttenwesen", Vienna 1873
Michael Kefer "Hand Karten des Ischler Salzberges", 1829, Transcription Nussbaumer, April 30, 2019, Archiv Salinen Austria
Carl Schraml "The Upper Austrian Salt Works from 1750 to the time after the French Wars", Vienna 1934
Carl Schraml "The Upper Austrian Salt Works from 1818 to the end of the Salt Office in 1850", Vienna 1936
NN "Water channel made of ashlars", Ischler stock book no. 50, transcription Thomas Nussbaumer, 01 07 2018, archive Salinen Austria
Ischler Salzberg, Rinnwerk Reinfalz, 1907, plan archive Salinen Austria, archive number BI - 35 - 13214
Alfred Pichler "Lipplesgrabenstollenhütte", LVFH Upper Austria, Linz, 2003