Neprehojene Poti 2016
An Imperial College Caving Club expedition to Tolminski Migovec in the Julian Alps (NW Slovenia)
Aims and objectives
The main goal of our planned 2016 expedition was to give Primadona the sustained focus of expedition cavers. As well as rerig and resurvey Primadona to a high standard and in a systematic fashion, we aimed to develop a working knowledge of the cave. The exploration target of the Neprehojene Poti expedition to Slovenia was “Primadona”, a 600 m deep cave with an entrance imposingly 120 m down the cliff on the Western side of the Migovec plateau. Our objectives were:
- to teach novices how to rig, bolt and survey cave passages
- to bolt a new access route to Primadona using standard alpine SRT techniques
- to systematically explore and survey passages in order to…
- produce a high standard (BCRA grade 4b) survey of the Primadona-Monatip system
Two main regions of Primadona require our attention in future, both with showing good promise of development. The first is the old, deep pitch series, left unvisited below the Adjovcina pitch due to time constraints. The state of the ‘lead’ at the limit of exploration is unknown, but may hold the key to reaching a magic ‘-600 to -800 m’ structural level, which has proved very fertile in Vrtnarjia. The second is the major horizontal development named ‘Smer0’, heading north from the start of Galerija, at -250 m from the entrance of the cave. Several other undescended pitches at various levels of the cave were left due to time or logistical constraints, namely above and below TTT pitch on the Povezava branch, and off the horizontal levels of the Monatip side of the cave system. Finally, several leads at depth in Vrtnarija remain unpushed but necessitate the set-up of an underground camp. Those are described in the 2015 expedition report.
Exploration in Primadona
1) Karstaway-Mighty fine indeed
Karstaway is found at the bottom of Rokovo Brezno, on the Galerija branch below Sejna Soba. At the bottom of the 30 m pitch, a series of downclimbs in a sinuous rift lead to a small chamber formed at the intersection between the rift and a fault plane which carries a small stream. Upstream of the chamber, a small aven with calcited mud floor and haematite pebbles can be accessed. Downstream the rift closes down to a passable plane, covered in black popcorn formations. Further on the passage widens and the clean washed walls under a drip reveal a much cleaner white limestone. The passage bends away from the fault plane at a 10 m high aven, and the way on is on the high level of the rift, abandoning the streamway to reach the scalloped walls of the ancient phreatic conduit. After an S-bend, the passage continues to the west, with white limy mud lining the pockets of the walls of the same colour. The draught is followed downwind all the way to the top of a 20 m pitch, the end of Karstaway.
It is possible to drop down to the streamway further back in the passage, and two such approaches lead to undescended drops, which do not appear to connect with the pitch further west. At the pitch head, a clean hang drops into Mighty Fine indeed, a three-pitch series.
The Hall of the Mountain King is large cavern in which Mighty Fine indeed drops. The boulder floor has several leads to a small, immature streamway. The rock is jagged and sharp and very friable. The cavern itself is elongate in the W-E direction, with two separate avens coming in the middle and far end respectively. The western side of the Hall of the Mountain King narrows to a 5 m wide, weakly sinuous rift, with a 5 m climb barring progress at the end. Up the climb leads to a short elevated platform which drops into a perpendicular passageway, heading NNW-SSE. To the north, a 30 m long passage, Colony follows a fault line, with different levels separated by wedged boulders and stops overlooking a chamber of large dimensions.
Exploration in Monatip
The start of the passage is found below Big Chamber in Monatip. Upon reaching the rift, a traverse onwards is the way to the old connection with Sejna Soba in Primadona. By bridging the rift and clambering in the opposite direction, the ceiling of the passage drops. A climb up leads to the left hand wall of a 3×3 m chamber. An obvious phreatic tube, taking a very small amount of water, leads to the SE. It dips almost constantly at 10°, and takes a good draught. The passage intercepts another chamber, plastered with mud, where a way on can be seen back underneath a downclimb, 4 metres below the incoming passage. The way on is on the opposite side of the chamber, as the continuing tube. A four metre upclimb, and the passage continues as a phreatic tube until a junction is reached. On the right, the tube ascends gently to a pitch head twenty metres away. The pitch is as yet undescended.
An impressive 2.6 km long cave in its own right, Primadona was connected in to the rest of System Migovec over the autumn of 2015/2016 by our partner club the JSPDT. The exploration was mainly focused in an area known as Galerija and over the course of the expedition was pushed 190 m deeper with 835 m of new passages finally ending in a series of impressively large chambers.
As anticipated, we gained a better understanding of the quantity and complexity of cave at the western edge of the plateau. Unfortunately this year was not without incident and one of our party was injured whilst exploring 200 m underground. Thanks to the exemplary reaction of all members of the expedition and heroic efforts of the Slovenian cave rescue service he was safely brought to the surface and is now fully recovered.
Text: Benjamin Honan
Photos: Tanguy Racine