PRELIMINARY REPORT
The aims of the Mulu 2023 expedition were threefold: firstly, to continue the exploration of high levels in Clearwater Cave via Leopard cave entrance to find the presumed missing passages between Api Chamber and The Hidden or Paku Valleys; secondly, to continue the scientific studies to improve understanding of the role of various guanos in the enlargement of cave passages; and finally, to continue 3D mapping of the larger passages in the Clearwater system.
The expedition brought three scientists and sixteen cavers from the UK (10), Malaysia (3), the USA (2), Poland (2), France (1) and Slovenia (1), with 4 younger members visiting Mulu for the first time. On top of this we were ably assisted by six local guides.
Exploration
Despite two camps totalling six nights underground the team found a number of small leads but nothing of significance in Leopard Cave. A somewhat despondent team reverted attention to The Cairn Farm, beyond Armistice in Clearwater. This had been a region rarely visited as just to reach it takes over eight hours of involved caving. A first camp yielded little, but a second camp found a way on beyond the farthest reaches of the known cave to discover a very large chamber and 800m of huge passage 50m wide and 100m high which led straight to the boulder choke under Api Chamber. Called Defiance, whilst modest in length, this passage is arguably the most significant discovery in Mulu for ten years as it fills a huge gap in the survey and addresses the question of what happens to Day-Dream Believer passage in Whiterock Cave after it is blocked under Api Chamber. Does this mean that there is no huge passage all the way from Api Chamber to the Hidden Valley or the Paku? This discovery suggests that there is not, but it is too early to be sure.
Exploration in both Easter and Lagang’s caves still failed to make a connection between these caves, a connection that must exist given that they overlap each other in several places.
Laser Scanning
The 3D mapping project continued collecting data from the clearwater system and has now completed a survey from Snake Track to Cave of the Winds including the major passages between Snack Track, Clearwater I, Cave of the Winds and Clearwater III. It proved to be much more complex a project than imagined as none of the huge passages proved to be straight-forward to scan. The major objectives were all mapped but high water prevented scanning all the way to Berangs entrance. The scans have revealed about twenty tantalising new leads for future expeditions.
Science
The science projects set out to understand the source of additional aggressive chemicals that drive dissolution of limestone and hence the development of the huge cave passages and unique scalloping we find in Mulu. Early results show that ammonia originating from all guanos results in acidic NOx which accelerates limestone dissolution. Additional results indicate that hydrogen peroxide, which is found in swiftlet, but not bat, guano is also an aggressive factor. The source of the hydrogen peroxide is not yet understood. All these results require confirmation, but it is increasing clear that additional airborne acids play a significant part in the development of the Mulu caves.
The Team
Leader: Andy Eavis
Scientists: Andy Farrant, Hazel Barton, Max Koether
Cavers: Dave Nixon, Colin Boothroyd, Nigel Boothroyd, Simon Cundy, Chris Blakeley, Roo Walters, Bartek Biela, Paulina Biela, Joe Daniels, Anja Hajna, Russell Myers, Rostam Namaghi, Rida Rambli, Zarris Zem, Rambli Ahmad.
Initial Local Acknowledgements:
Sarawak Forestry Corporation: The Controller of National Parks & Nature Reserves – Zolkipli Mohamad Aton also Mulu Park Warden: Mark Kuneiglibuan Tisen and his staff
Borsarmulu Park Enterprise Sd Bhd Park Manager – Hein Gerstner and his staff
Field Foreman – Veno Enar
Local Guides – Kenneth Nilong, Jimi Jarau, Jarau Pa’eh, Steve Lian and Hennyson Yakop.
25th Nov 2023