The Ljubljana Cave Exploration Society (, DZRJL) is a Slovenian non-profit speleological organization founded in 1910 dedicated to the discovery, exploration, documentation and protection of caves in Slovenia. It is based in Ljubljana, is the oldest still active caving society in the country and is most known for its work in the deep caves of the Kanin mountain range. It discovered, explored and surveyed five caves, deeper than 1,000 meters; the 2019 connection of two such caves reduced the figure to four.
Early history
Exploration and documentation of caves in what is now Slovenia began with the publication of the book The Glory of the Duchy of Carniola by Johann Weikhard von Valvasor in 1689, and continued with the works of Joseph Anton Nagel (1748), Franc Anton von Steinberg (1758) and Adolf Schmidl (1854). At the end of the 19th century, the focus of cave exploration was in Škocjanske jame and the Postojnska jama. It was mainly driven by the administrator of the latter cave, Ivan Andrej Perko. After 1885, on behalf of the Ministry of Agriculture in Vienna, Viljem Putik (aka Wilhelm Putick) was exploring the karst in the hinterland of the karst fields in the Inner Carniola.
At the initiative of Perko and Putik in 1910 in Ljubljana the Cave Exploration Society (Društvo za raziskavanje podzemskih jam in Slovenian, Gesellschaft für Höhlenforschung in German) was founded. It was presided by baron Theodor Schwarz von Karsten, at the time regional president of Carniola, crown land in the Austro-Hungarian Monarchy. As only two members of the society had experience in caving, the secretary, Josip Cerk, invited a group of mountaineers and alpinists, called Drenovci, to conduct cave exploration for the society. After the death of Josip Cerk during the winter ascent to Mt. Stol in 1912 Pavel Kunaver took over the exploration leadership. Society was divided in two sections: the main Lower Carniolian Section [Dolenjska sekcija], of predominantly Slovenian-speaking members and the Kočevje Section [Gottschee Sektion] of German-speaking members - Gottscheer settlers - they explored the caves in the former Gottschee county till the WWI.
In 1911 Drenovci, within Lower Carniolian Section, began to identify underground inflows into the Krka river and therefore set out to explore the deep abysses, in order to reach the water caves below. In addition to usual caving equipment (roll ladders) they also used rope and mountaineering techniques. The first important achievement was 84 meters deep abyss of Marjanščica. It was followed by Žiglovica (82 m), Krviška Okroglica (93 m), several ice caves on Velika gora, the cave Tentera. At the initiative of Viljem Putik they also explored 200 meters of new tunnel in the north branch of the cave Logarček on Planinsko polje.
The principal photographer was Bogomil Brinšek, who used flat magnesium ribbon wound around a hammer as a source of cave illumination. His artistic depiction of mountain and cave scenes, often in pictorialist style attracted many to photography, first of all Ivan Tavčar and Josip Kunaver.
The society became known in the wider area, it was invited to explore caves in Pazin and Baderna, Istria, where the main achievement was the descent in 97 m deep cave Golešička (Golešnica), in search of an underground water source. Until the outbreak of the First World War in 1914 the society explored 133 caves.
WWI interrupted society's activities, Bogomil Brinšek was killed in the first days of the war, but it did not stop the speleological work of the society members. Pavel Kunaver, as a non-commissioned officer of the Austro-Hungarian army, participated in the exploration and adaptation of caves in the Karst area for military needs. Later he joined the special caving group led by Lieutenant Ivan Michler, also a society member, to explore caves in Trnovski gozd and Banjšice, in the immediate hinterland of the front line in the Battles of the Isonzo campaign. In 1917, Kunaver and Michler explored over a hundred caves for military purposes. On August 31, 1917, they in one go explored the abyss Roupa to the depth of 146 meters, which remained the society's record achievement until 1965.
Between the two wars In the two decades after the World War I, DZRJL established itself as a full-fledged caving organization. During 1,264 field trips 742 caves were explored.
Pavel Kunaver published the book Karst world and its phenomena [Kras in kraški pojavi] in 1922, the first Slovenian popular science book about Karst, to awaken the Slovenian public to caving and speleology. But the timing was not yet suitable. His second book In the Abysses [V prepadih, 1932] also did not meet the expected response. DZRJL activity resumed in 1924, the society changed focus from topographical discovery of the underground to the scientific study of karst phenomena. The seat of the society was established at the Zoological Institute of the University of Ljubljana - since 1927 DZRJL was chaired by the zoologist Jovan Hadži. In the summer 1925, the first caves after WWI were explored, Zlatica and Govic, the partly submerged spring cave, both above Lake Bohinj and 4 caves in the vicinity of Škofja Loka. In 1926, the cave Županova jama was discovered by Josip Perme, the mayor of Ponova Vas, which soon became one of the most visited Slovenian show caves. In the same year it was explored and surveyed by DZRJL (it is 710 meters long and 73 meters deep) and the society's member Valter Bohinec published a monograph about the cave, the first speleological treatise in Slovenian. It includes extensive instructions on the work of a physical speleologist in a cave. In 1927, Roman Kenk and Albin Seliškar have set up one of the first laboratories worldwide for the study of cave fauna in the cave Podpeška jama.
In 1929, the society conducted exploration of caves in the wider area of Loško polje. The main achievement was the exploration and survey of the inner parts of Križna jama, discovered in 1926. More than 5 km of water tunnels have been explored and surveyed. In 1931, DZRJL explored the cave Vjetrenica in Herzegovina and surveyed several kilometers of tunnels, making it the longest cave in the Kingdom of Yugoslavia. In 1932, the search for Lipertova jama, lost after the death of its discoverer, Viljem Putik in 1929, was restarted, and on August 12 the cave Krastača, later the second entrance of Najdena jama, was found. In 1933, Albin Seliškar performed one of the first cave dives in the world in an atmospheric pressure diving suit, in Pod stenami sinkhole at the north edge of Planinsko polje.
The middle of the 1930s was the boom time for the Logatec branch of DZRJL. Under the leadership of Ivan Dolar, they systematically explored caves in the wider surroundings of Logatec and penetrated to the end of Blata branch in Križna jama. In 1937, while the DZRJL group was scouting the area to find Lipertova jama, Alfred Šerko Jr., with the help of a survey based on the land cadastre, produced by mining engineers Kersnič and Lučovnik from Ljubljana, discovered the entrance to this cave (Alfred Šerko Sr., his father, was a renowned Slovenian neurologist and psychiatrist). The upper part of the cave exactly matched the Putik's description and his map, but as the water tunnel was much smaller, Šerko concluded the cave is not the same and named it Najdena jama [Found cave]. In 1938, Šerko rearranged the DZRJL cave registry - he sorted the archive of excursion records by cave, gave caves cadastral numbers and compiled the List of caves in ozalid technique.
In the late 1930s, Šerko and Ljubo Podpac organized systematic exploration of caves along the border with Italy. Detailed search for caves on Pokojišče Plateau and on Begunjski Ravnik has also been made. In 1939, Ivan and Dušan Kuščer made a dive into Malo okence (8 meters deep) and Veliko okence (the first siphon, 4 meters deep and 10 meters long) karst springs of Ljubljanica river near Vrhnika with diving equipment of their own design and manufacture. From 1926 the principal DZRJL photographer was Franci Bar, who used flash powder as the main source of underground illumination. He also perfected the cave stereo photography.
Najdena and Žankana jama After the turbulent times in the 1940s, the society reached the second peak in the 1960s with the discovery of a large cave after the tight passage at the end of Najdena (Lipertova) jama was broken in 1963, and the exploration of deep caves in Slovenia, such as Triglavsko brezno and Medvedova konta on Pokljuka plateau and the deepest cave in Yugoslavia, Žankana jama.
During the Second World War, Valter Bohinec and Jovan Hadži hid the society's archive in the premises of the National and University Library in Ljubljana. As the Slovenian anti-Nazi resistance units often used caves as hideouts, cave locations and maps in this archive were of great military importance. The archive of the Kočevje Section of DZRJL was stored in Kočevje and was burnt in December 1943 during the Battle of Kočevje. Only a few fragments survived, stored in the main archive (of the cave Vodna jama pri Klinji vasi).
In 1945, the DZRJL activity resumed, exploration began also in the now again accessible Littoral Karst. It was reflected in the book by Šerko and Michler: Postojnska jama and other attractions of the Karst. In 1948, the society suffered a great loss with the sudden death of Alfred Šerko. During a speleological field trip in Istria he got out of the car he was driving and as he was still holding the door handle the lightning hit the car, killing him while the other passengers in the car remained unharmed. His role was taken over by Ivan Michler and systematic exploration of the underground between Planina and Postojna began. Pavel Kunaver successfully promoted caving by organizing field trips to caves as part of the extracurricular activity at the high school in Ljubljana where he was a teacher. In 1950, in Planinska jama, a bifurcation was discovered in the Rak river arm of this cave. In 1951, in the Velika Paradana ice cave a new pit was discovered, cave depth was increased to 120 m. The first major discoveries were made, after almost ten years, in the cave network of Postojna Cave. In the same year, the DZRJL Postojna branch was established. Its main exploration area was the cave behind the Predjama Castle, where a large cave network was discovered. In 1954, the First Yugoslavian Congress of Speleology was held in Postojna, organized in large part by members of DZRJL. To conform to the statute of the Speleological Association of Yugoslavia, which required cover organization in every of the Yugoslavian federal republics (regions), DZRJL was renamed to Cave Exploration Society of Slovenia (DZRJS).