A quarter-century of toil in the cave Luftloch
a new path to the Reka River - 2025-01
The underground flow of the Reka river, which has sparked curiosity and tested the perseverance of researchers for almost two centuries, is accessible only in a few caves in the karst region between Divača and Trieste. Besides the Škocjan Caves, where researchers followed the Reka River, two caves stand out historically as the most notable – the cave Kačna jama near Divača and Labadnica (Grotta di Trebiciano) between Orlek and Trebče on the Italian side. Both witnessed events of biblical proportions as early as the 19th century. The so-called Grottenarbeiter or cave workers had to overcome deep abysses using the techniques of the time, equipping them with ladders. These feats remain monumental achievements even today.
In recent decades, tireless cave explorers have managed to reach the underground flow of the Reka river in other caves as well. Originally, these caves were known as blowholes, through which the rising Reka would force air out of the underground chambers with incredible power. However, the entrances were extremely small or ended in collapses after just a few meters, making deeper descent impossible. The path to the Reka from the surface is extremely deep, requiring more than 300 meters to be overcome. Modern-day Grottenarbeiter had no choice but to dig, widen, and reinforce the passages to reach the long-desired underground watercourse.
The underground Reka river first appears on the Italian side of the border in Labadnica. Diving explorations have been ongoing in the cave for years, where French divers, with the help of Italian and Slovenian cavers, overcame a siphon over 300 meters long and discovered a new big chamber. This chamber continues with another siphon, which has yet to be explored. Only after more than three kilometers in a straight line lies the entrance to the next cave providing access to the Reka, the renowned cave Lazzaro Jerko. Here, after three years of intensive work, cavers reached the Reka 25 years ago. Shortly after this discovery, a new site was opened not far from Labadnica. In the year 2000, members of the Trieste-based caving club Società Adriatica di Speleologia were impressed by the powerful airflow of the rising Reka in the large sinkhole Cloce.
Following the discovery of this airflow, Marco Restaino and Piero Slama began excavating in the sinkhole, unknowingly starting a two-decade-long odyssey to their desired goal. With the help of numerous cavers, they first started digging at the most promising blowhole. After breaking through an initial blockage of soil and squeezing through a narrow passage, they discovered a cave chamber at a depth of 20 meters, named September 11 after the date of its discovery. However, this chamber did not continue further. Over time, their excavation site collapsed, and the lower sections were no longer accessible. Despite the setback, they began digging at a second location, aiming to reach the known cave chamber. However, when they encountered rocky barriers beneath the soil, their motivation waned, and they abandoned the effort. After a pause, they began digging at a third location, where they finally succeeded in reaching the previously known September 11 cave chamber.
Due to the instability of the excavation, the 20-meter entrance shaft was reinforced with concrete and equipped with ladders. The continuation of the cave was sought in the direction of a faint airflow, with cracks being widened and reinforced using construction pipes and meshes, extending to a depth of 50 meters. The cave was named Luftloch, symbolizing the effort of the cave workers and their pursuit of the airflow.
After eight years of hard work, the cave finally widened, but numerous passages still needed to be discovered, hidden at the bottom of each level. Within two years, they reached a depth of 235 meters, only to encounter a new challenge. The oxygen content in the air decreased significantly with depth, while carbon dioxide levels increased. To address this, they decided to use a fan to blow air from the surface through pipes to the lowest point of the cave. This method proved highly successful, significantly improving air quality throughout the cave.
Finding the continuation of the cave also became increasingly challenging, as they could no longer find the deep abysses that had quickly brought them into the depths. Their only hope lay in a small crack, through which a hurricane-like draft blew, indicating the only possible direction forward. What followed was more than a decade of widening the narrow passage and searching for continuations, guided mostly by a faint draft. After excavating 40 meters of passage, the tunnel finally began descending again. After a brief narrow section, they faced a 50-meter descent into a spacious chamber. In late March 2024, after 23 years of excavation and exploration, the team finally reached the bottom of the cave and the long-sought Reka River.
The total length of the passage at the bottom of the Luftloch cave is about 300 meters, but the flow of the Reka can only be followed by boat. Downstream, we can reach another chamber where it is possible to disembark, but shortly after, the passage ends in a siphon. The upstream passage is shorter and narrower, leading to a smaller chamber that also ends in a siphon. This siphon is approximately 200 meters away from the last known sections of Labadnica, presenting a realistic possibility of connecting the two caves. However, this will require the help of cave divers, as connecting the caves on dry ground is impossible.
Luftloch is, of course, not the only cave in the area where cavers are venturing into unknown depths, but it is one of the few where explorers have achieved their dream goal practically from scratch. This success was only possible after nearly a quarter-century of persistent exploration and hard work, rewarding the team with the Reka River and one of the most beautiful journeys to the underground river.
