Laci Pothole

Laci-zsomboly is a cave located on Csúcs Hill in the Pilis Mountains within the Danube–Ipoly National Park, in the outskirts of Csobánka.

Description

From the Oszoly–Csúcs Hill ridge southeast, 380 m north of the summit of Csúcs Hill, in a gorge the trail starts, 250 m away, in the forest, 20 m south of the trail, on the mountainside. On the trail a small sign points to the artificial vertical shaft entrance of the cave, 1.8 × 1.7 m in diameter, which opens under a small rock overhang. Its entrance has been concreted so that the upper, unstable part is secured.

The pit formed in Upper Triassic Dachstein limestone. An oval, lower siliceous slab‑like, nicely finished entrance shaft descends at a 60° angle to the middle of the shaft, then becomes vertical. In the dry, approximately 10 m deep, clean shaft the use of rope and rope‑technical equipment is required.

A cross‑direction fissure starts from the shaft. After that a short horizontal section follows, after which humus gradually fills the passage. The cave is very tempting for further progress because there is an air‑filled corridor in the narrowing passage. Progress is almost certain after the filling material is removed. Traces of the ongoing exploration work can be seen at the cave entrance and at the bottom of the shaft.

In 1989 the cave was first called Laci-zsomboly in the literature.

Research history

In early 1986 the Student Speleoalpin Group discovered the cave by excavating a pit. At that time the vertical cave passage, which received the name Laci-zsomboly, was revealed. On 18 April 1986 the discovery was reported to the OKTH. The 1989 group report included a topographic map and a site drawing showing the cave’s location. The report contains a description of the cave’s investigation and two photographs in which the cave is visible. The manuscript states that in recent years the group cleared the pit and at a depth of 1.5 m the members removed rock debris.

The vertical passage after another one and a half meters sank into a fissure and continued in a shaft. The then endpoint was 6 m deep. The endpoint is filled with loose, rocky debris and a weak draft flows through the gaps. The one‑and‑half‑meter‑diameter entrance section collapsed so much that at the bottom of the shaft the group considered the demolition difficult because of constant collapses. Continuing the exploration work would have been very dangerous. The members planned to continue the demolition in the cave after securing the entrance section with a scaffold. In 1990 a news item appeared in Karst and Cave about the continuation of the cave exploration research.

Kárpát József drew the cave length‑section map and two cross‑section maps in 1990. The maps present the cave at a scale of 1:100. The USE Pannónia Cave Research Group had a research permit in 1990 for the Laci‑zsomboly investigation. In the manuscript written by Kárpát József in 1991 it is mentioned that the Laci‑zsomboly (Pomáz) is 7 m long, 6 m deep and under investigation. Sándor Kraus drew a site plan in May 1997 showing the geographic location of the Csúcs‑hegy caves. The plan shows the geographic location of the cave marked Laci‑zsomboly. In Sándor Kraus’s 1997 report it reads that Laci‑zsomboly, known before 1997, already had a map before 1997. A significant cave that requires further research. The site plan made in 1997 was included in the report.