PRELIMINARY REPORT
The expedition arrived in Gunung Mulu National Park on 29th December 2019 and departed on 17th January 2020. Once preparations had been made at Park Headquarters the expedition left for Camp 5 on 31st December and stayed there for a two week period.
The expedition’s sole focus was on the caves of Gunung Benarat with the following objectives.
1. To explore leads left by our previous expeditions in the Benarat Caverns System at the southern end of the mountain.
2. To explore underground leads at the northern end of the mountain in the Terikan River System.
3. To identify and explore any leads which may make a connection between the two systems.
4. To investigate surface features for caves
5. To review the survex database for Benarat and make improvements where possible.
Results
Caves at the southern elevation of Gunung Benarat.
Sakai Cave
This cave had not been entered since the 1984 expedition. Reports from that time suggested exploration was rather unpleasant compared to the other great Mulu caves. This was not the case and Sakai was found to be a fine prospect. Once the entrance series of five rope pitches had been rigged exploration focused on the northern limit. A good draught throughout indicated potential and an easy way on was soon discovered. This led into a sizable chamber over 70m across but the only way forward was up a considerable vertical wall. This was climbed for 60m only to reveal a choked continuation. The source of the draught remains a mystery. A photographic record was made of the cave.
Moon Cave
This cave is located some 50m above the top of the southern scree slopes. Its position was located and the route to the entrance reclimbed. A descending passage called ‘Cake & Cheese’ had been left in 2007 at the head of a pitch into a large chamber. This was descended, but beyond the chamber, routes closed down between muddy boulders.
Caves at the northern end of Gunung Benarat:
Blue Moonlight Bay Cave
The entrance to this cave lies three and a half hours from camp five within the rugged limestone terrain. It forms the upstream section of the known Terikan River System. A camp was required deep into the cave in order to access two identified leads. At the far end of the main trunk route, the Casting Vote, a pitch in the floor was descended. It proved to be 70m deep and led to a descending mud and boulder slope to a static sump chamber. The end of the un-named southern trending passage was also investigated. Beyond the survey difficult climbs led up into a large chamber with a possible high level continuation. A climb across the roof was started but time forced a retreat before any continuation could be gained.
Troll Canal
This is a medium sized resurgence by Mulu standards located below the Elevator Entrance to the Terikan System. Its source is unknown. The active resurgence was reported to continue in fast water. It was found to sump a short way beyond the previous limit. Above, a number of entrances around the Elevator were entered. It was clear that some of these passages did not appear on the 2003 survey and although some resurvey was made it became clear this was too large an undertaking in the time available.
Cobweb Cave
and a possible connections between the two Benarat systems.
Direct access to Monolith Passage and the Elephant Warren was gained by a long detour to place a rope on the Monolith pitch. At the junction of the two passages a climb into an overhanging roof passage had been reported. This turned out to be some 55m from the floor. But a slightly shorter route was traversed, in order to gain a lower entrance. Fortunately this led via a difficult and complex series of small passages to emerge into the floor of the higher passages. From here a route similarly emerged into the high level passages of Just a Mile, discovered in 2000. This made exploration of leads in this series then possible via the new route. A camp was placed in Monolith to facilitate exploration. A serious climb from Outrageous Junction led to unentered passages heading south which soon dipped down to the same levels as the Elephant Warren. From this passage other leads headed north to come within 200m of known passages in Deception Cave, a part of the Terikan River System. Several open leads were left in this area due to a lack of time and no investigation was possible of the likely connection area.
Investigation of surface features:
Corner Cave
This is an entrance feature in the cliffs of south east Benarat located high above the screes and below the prominent prow. Attempts were made to reach it in 2015 and although a point beneath the entrance was located, climbs failed to reach it. In 2020 a lot of time was spent trying to find an overland route to the base rather than using the river as had been the approach before. Climbs up the cliff again failed due to lose rock and the difficulties finding a route leading in the right direction. Future efforts will need to find a new route up the cliff but it is still unclear whether a significant cave exists at all.
Other choked entrances along the southern cliffs were noted and an attempt was made to gain access to one which draughted heavily over solid calcite without success.
The survey database for Benarat:
There is much scope to improve the database for the Benarat caves. A number of the principal caves of the mountain are underpinned by reconstructed data which will at some future stage need to be resurveyed. Beyond these bigger issues the expedition techies have developed some improvements to the dataset which can be applied to all sectors as required. The ‘Splay Chomper’ programme automatically comments out splay legs from the raw survey files and relocates them below the normal data. Therefore the ‘hairy monsters’ some parts of 3D display has become disappear whilst the data is still retained for use as necessary. In addition the new *solve command has been used to great effect to solve large loop closure errors between the reconstructed data and the normal survey data. Some resurvey, for the time being, has been marked with the *duplicate command.
The stats:
The expedition showed that despite a lot of hard work new cave passage was difficult to find under Benarat. The new finds in Cobweb were very remote (five hours caving from the underground camp!) and their discovery near the end of our stay meant that they could not be fully explored.
Field calculations only. Refer to final report for full details.
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Team
From the UK – Tim Allen (leader), Diane Arthurs, Mark Burkey, Toby Buxton, Simon Cornhill, Ben Enticknap, Rachel Findlay, Chris Haigh, Frank Pearson, David Rose, Mark Sims, Mark Wright.
From Sarawak – Rambli Ahmad, Veno Enar, Steve Lian, Joe.
Acknowledgements
In Sarawak:
The Chief Minister of Sarawak
The Sarawak Secretary of State
The Director of Forests, Sarawak
Protected Areas & Biodiversity Conservation Unit, Sarawak Forestry Corporation
The Sarawak Ministry of Planning and Resource Management
The Resident, Miri Division
The Sarawak Immigration Department
The Sarawak Police Department
Gunung Mulu National Park Management & Staff
Hein & Andia Gerstner
In the UK:
Ghar Parau Foundation
Richard Walters
Matt Kirby
Rob Middleton and members of the October 2019 Mulu expedition.