The 2019 expedition was
undertaken with collaboration between numerous UK based caving clubs and the
Spanish AD KAMI club, under the banner of the Tresviso Caves Project.
As per previous year’s most of
the work was concentrated on two main caves, close to the village of Tresviso.
Firstly, Cueva del Nacimiento, a >13km cave system with a height gain of
over +535m from the entrance. The
catchment of this cave totals 37 km2 and, if linked with known cave
systems high in the Andara mountain range, would create a potential >1500m
deep underground traverse, one of the deepest in the world.
The second main cave of
interest was Cueva de la Marniosa, slightly further up the valley and a
feeder system into Cueva del Nacimiento.
On the 2018 expedition a new entrance to the cave was discovered,
creating a -423m deep through trip. A
side objective of the 2019 expedition was to attempt this first through trip.
In addition, the ongoing re investigation of some of the caves on the higher Andara range was continued.
The 2019 expedition has continued
to build on the successes of previous trips advancing exploration in line with
objectives and discovering over 1.5km of new cave and several new leads. Over 2km of existing cave was also resurveyed
to improve accuracy of old data and provide a better picture of the
Cueva del Nacimiento
Friends sump was successfully dived during the expedition. It took 3 days
to rig and re-survey the route to the sump, before the dives could be
attempted. Over 400m of new passage was
discovered, covering 3 sumps and a 4th un-dived sump. The new sump was proven to follow the main Nacimiento route through the mountain, but at a lower level, and is the same water as seen
at the Far Upstream Sump.
A trip to Dan’s
Big Room, to investigate the unexplored maze, was undertaken but time and
route-finding issues prevented any progression in the area.
As part of the Parting
Friends dive, the preceding Road to Wigan Pier streamway,
from the Black Hole, was re-surveyed to BRCA grade 5 standards,
replacing the previous 1986 grade 2 survey.
This work will be continued in 2020.
Likewise, the Outer
Mongolia passage, leading away from Clapham Junction was resurveyed,
with a few potential leads confirmed.
Cueva de la Marniosa
In the Extra
Caverns Series, several leads were explored. The Free Willy Aven was aid climbed to
a height of 23m across 3 separate avens, the first one becoming impassable, the
second one leading to a further unclimbed aven and the main aven still
continuing, but with a possible lip to the aven in sight, a further 10m
higher. This will be revisited on the
At the southern end
of the series, two small avens were climbed to a continuation into Forgott
Passage. 23m of passage leads to two
more unclimbed avens.
During a surveying
trip a large void above the main streamway was scaled and entered the large Alien
Weaponry chamber. Not shown on any
previous surveys, this chamber was a significant find, over 100m x 50m x 25m in
dimensions and multiple leads discovered.
Similarly, below the entry point to the chamber a new inlet streamway
was discovered. Again, this is not on
any survey and appears unexplored. The
passage was named The 42 Streamway (for the closest surveying station)
and heads south into the Valdelafuente ridge.
These will also be major objectives of the 2020 expedition.
In Cueva de la Silvestre, an unexplored dry lead near the entrance series was extended
for 62m to a boulder blockage. Bob’s
Crusade Sump was dived for 32m to a potential tight diggable lead and the Wet
Willy Sump was passed after 3m to 40m of streamway and a second 10m
sump to a tight continuation
T20A Cueva de la Silvestre – Cueva de la Marniosa through trip
de la Silvestre was rigged on the first day of the expedition and the first
through trip was undertaken the following day.
A team of 4 completed the trip in just under 6 hours. One further through trip was completed before
the Silvestre side of the trip was de-rigged. After 41 years of exploration, these were the
first subterranean traverses of the mountains in the area.
overall cave system is now 6,300m long and -423m deep (from the Silvestre entrance to the furthest point beyond sump 2 in Marniosa). It is now the 2nd longest and 10th deepest cave in the Tresviso – Andara region.
Minas de Mazarrasa
T145 Pozo del Castillo was revisited, following the
passing in 2018 of the snow-plug that had blocked the route down into the cave
since the 1980’s. Unfortunately, further
collapse has blocked the way once again.
T145 Cuesta was explored further, passing an old wooden
bridge across a large pitch. The passage
beyond and the lower levels were explored and resurveyed. Although a few sections were unexplored,
potential appears to be limited.
However, in future an attempt will be made to enter the cave via the
higher T123 ROSA entrance to explored and complete a fuller survey.
other old mines were revisited, including T144 Rosario and T436 El
Queso. In both cases no previous
survey existed and a new BCRA grade 5 survey was commenced for both. T436 El Queso has now been shown to
pass within 5m of passage in T145 Pozo del Castillo. Examination of the surrounding area is
recommended for future trips to look for potential ways past the snow blockage
Sierra del a Corta
Several leads were identified
and T48 La Torca Grande was revisited, but unfortunately still contains
a large snow plug preventing further progress, despite there being very little
snow compared to previous years.
As per previous expeditions several old sites were revisited and cataloged, plus several new leads for future trips were identified.
|Alastair Gott||Technical Speleological Group||UK||2019||Tresviso 2019|
|Arwel Roberts||South Bristol Speleological Society||UK||2019||Tresviso 2019|
|Bob Clay||South Bristol Speleological Society||UK||2019||Tresviso 2019|
|Derek Cousins||Lancaster University Speleological Society||UK||2019||Tresviso 2019|
|Howard Jones||Lancaster University Speleological Society||UK||2019||Tresviso 2019|
|Joe Daniels||Individual||UK||2019||Tresviso 2019|
|Leo Bradley||Sheffield University Speleological Society||UK||2019||Tresviso 2019|
|Lisa Boore||Chelsea Spelaeological Society||UK||2019||Tresviso 2019|
|Lydia Clare-Leather||Sheffield University Speleological Society||UK||2019||Tresviso 2019|
|Phil Walker||Bradford Pothole Club||UK||2019||Tresviso 2019|
|Rob Middleton||Bradford Pothole Club||UK||2019||Tresviso 2019|
|Stuart Coxon||Bradford Pothole Club||UK||2019||Tresviso 2019|
|Toby Dryden||South Wales Caving Club||UK||2019||Tresviso 2019|
|Will Burn||Sheffield University Speleological Society||UK||2019||Tresviso 2019|
Thanks also due to Nick Airey, Jos Beyens, Colin Boothroyd, Ken Daykin, Fernando de la Fuente Moreno, Carolyn Ginnever, Tim Nichols, Mark Sefton, Sheena Stoddard, Jim Thomson, Ana Moradiellos Barreiros, UKCaving.com and the people of Tresviso.
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