Hollow world
Towering 20 metres above our heads, the ceiling of the passage presented a wide arc, 35 metres across and thickly coated with delicate formations. Despite the sheer scale of it, a cool breeze beckoned us into the unknown. The flat floor made for incredibly easy going, so I could forget where I was putting my feet and gape in awe at the distant walls, which were only just visible with my dimming headlight.
A distant echo came from my colleague, Tim Allen. ‘On station,’ he yelled. I stared into the black space, mesmerised by the wonder of what lay ahead, then quickly grabbed my compass and clinometer, took the necessary readings, and ran after him.
Gigantic voids
This is the nature of exploring caves in Gunung Mulu National Park in Sarawak, the Malaysian state on the northern side of Borneo. Here, the voids are of such gigantic proportions that it’s easy to believe that you’re on the surface surveying a cliff face at night, when you’re actually deep underground in a new chamber.
Ever since the first Royal Geographical Society expedition in 1978, when a team of scientists and speleologists descended on Mulu’s forest-covered landscape, cavers have been returning to the park every two or three years. These expeditions have mapped and documented more than 250 kilometres of cave, including the largest known chamber and passage in the world: Sarawak Chamber, which has a volume of more than 11 million cubic metres, and Deer Cave, where the average height of the passages reaches 120 metres.
In 2005, I took part in a four-week expedition to Mulu during which we discovered a significant new cave, dubbed Moon Cave after the snack of Chinese moon cakes that we were eating at the time, and explored it to a distance of about six kilometres.
We also conducted the first significant exploration of Whiterock Cave, which had originally been discovered in 2003 by two British explorers – Matt Kirby and Richard Chambers – who had spent most of their stay in the jungle close to the limestone escarpment hunting for a cave known as Blackrock. They never found it, but came across a small, draughty cave that seemed to offer great potential.
The 2005 expedition took those two explorers, along with 13 others, and myself back to this cave, where numerous imposing passages and tunnels were discovered. In total, we surveyed and photographed 19 kilometres of uncharted territory.
Both caves proved too large for us to explore fully, so in January this year, I joined an expedition that returned to the caves to attempt to finish the job. Over a four-week period, team members came and went, and at one point there were 14 personnel in the field, supported by local park guides. Several team members flew in by helicopter, giving them a chance to gain a perspective on the layout of the mountains and the positions of the caves within.
Return to Whiterock
Our first task was to relocate the entrances that the teams had used during the 2005 expedition. This provided an excellent opportunity to demonstrate track-cutting skills in some seriously dense forest. Swinging razor-sharp parangs, a small group cut through the vegetation to create a rough pathway – so indistinct that it was only really apparent to those who had cut it. We tried to keep the tracks hidden in order to protect the caves from local groups who destroy delicate formations as they collect the nests of swifts, which are used to make bird’s nest soup.
Once we had found the entrances, it quickly became clear that the passages we were hoping to follow were so far inside that there was no chance of safely exploring them in a day, so we decided to camp underground for several days at a time.
We set up a base camp in the Melinau Gorge and then the following day, two teams headed out to begin exploring the two caves. Both teams were heavily laden with large packs crammed with enough food – mainly pasta and tuna – to last them several days. Luckily, they didn’t have to carry water, as it was plentiful inside the caves.
A crystal maze
The five-person Moon Cave team, of which I was a part, crossed the Melinau River, north of Gunung Api, and headed for Gunung Benarat, the second in a row of three limestone mountains. When we reached the mountain, we got into our climbing gear and made the 60-metre ascent up to the cave’s entrance, which we had discovered during an attempt to bolt climb up to a higher cave located to the east of a cavern known as Tiger Cave.
Once inside, we made our way deep underground to an area where we’d seen some open passages, high up above our heads, during the previous expedition. However, after several hours battling up vertical walls encrusted with crystals, we were forced to settle for an early night back at our underground camp – christened the Geode Café – which was nestled in an alcove that sparkled delightfully when even the faintest light fell on it.
Indeed, the climbs in Moon Cave that had given us such high hopes in 2005 proved to be mere washed-out ‘solution cavities’ that only continued for relatively short distances before diminishing into nothing. The next day, however, we followed a second passage that proved to be considerably more productive.
The passage led to a heavily calcified boulder choke. After a bit of digging, it looked as if we might be able to make it through to the other side of the blockage. The ceiling was littered with sharp stalactites, and as we squeezed through, they repeatedly pierced our clothing, no matter which way we twisted and turned. This short, tight section burst into the side of yet another huge fossil passage that headed off into blackness.
With relative ease, we explored a respectable 1.8 kilometres of virgin cave, eventually reaching a point where another cave system intruded – we had connected Moon Cave (seven kilometres long) to Cobweb Cave (32 kilometres long). In 2005, we had also discovered a connection between Moon Cave and a cave known as Benarat Caverns, so in all, we had established that one of the cave systems inside Gunung Benarat is at least 50 kilometres long.
The discovery of this new connection proved to be one of the highlights of the expedition, and after three days underground, we jubilantly headed for the surface via the Cobweb Cave network.
Reconvening at camp
Meanwhile, in Whiterock Cave, the entrance to which was located about two hours’ walk from base camp, the second team managed to notch up another three kilometres of exploration in its first day. This increased the total explored length of the cave, which forms part of the maze of Clearwater Cave in Gunung Api mountain, to 29 kilometres.
The team spent the next few days exploring deeper into the cave, before they, too, returned to base camp for a rest day. These rest days allowed us to bathe in the river, eat some rather more interesting food and download survey data into our laptops.
This, then, became the pattern for the rest of the expedition. Teams would spend two or three days at a time in Whiterock– exploring new passages, filling in blank areas and establishing links between previously surveyed areas – and then come out for a rest day. We probably made half a dozen such forays over the course of the expedition.
During one such foray, one of the teams explored a major lead heading north, following it until its end – a mass of calcite and boulders just 373 metres from base camp. Unfortunately, there was no sign of any drafts, swifts or other evidence that the lead might reach the surface.
A subsequent trip to the same area uncovered another passage, 60 metres above this one that virtually duplicated the alignment of the original, lower passage. It, too, ended in calcite and boulders, this time 360 metres from base camp. This was very disheartening as it meant that, despite being so close to base camp, we had to retrace our steps back along a huge tunnel littered with boulders to our underground camp before heading out of the cave the ‘long’ way.
The final stages of the expedition were spent photographing the many discoveries underground and pushing those ‘can’t resist’ open passages at least as far as the next corner.
In all, we explored and surveyed a total of 25.8 kilometres of cave passages, including 21.9 kilometres in Whiterock Cave. The total length of the Clearwater Cave system was extended to 151.4 kilometres, confirming its current status as the world’s tenth longest.
We’re now planning to return towards the end of next year or the beginning of 2009 to continue exploring this spectacular hollow world.
Surveying caves
The most effective method for producing an accurate plan of a new cave is to ‘map as you find’. The surveying team (usually made up of three people) begins from the cave entrance or the last ‘station’ inside the cave and works its way inwards.
A station is a point of reference that indicates where you have surveyed to and where you plan to survey from. It could be an existing structure such as a boulder or a stalagmite, or it could be set up by one of the team members – a cairn of small stones, for example. The team will attempt to choose stations in passages where they can clearly see both the previous station and another suitable station farther in.
One member of the group stays at the first station, while another heads off into the blackness to the next one. The distance between stations is then obtained using either a tape measure or a laser meter. A compass is used to give a bearing and a clinometer provides the inclination between the two stations. These data are recorded in a notepad (usually on waterproof paper), and a rough sketch of the cave passage – including walls, ceiling, any obstacles and any rocks on the floor – is made on the adjacent page. At every station, four other measurements are taken. These are distance legs: left, right, up and down to the floor. It’s crucial that every measurement from a station is taken from the same place each time. This helps to create a more accurate survey once all of the data are entered into a computer program such as Survex, which combines the data to create a simple diagram of all the legs. From this, it’s possible to draw the cave to scale, both in plan and cross-section.
September 2007
A distant echo came from my colleague, Tim Allen. ‘On station,’ he yelled. I stared into the black space, mesmerised by the wonder of what lay ahead, then quickly grabbed my compass and clinometer, took the necessary readings, and ran after him.
Gigantic voids
This is the nature of exploring caves in Gunung Mulu National Park in Sarawak, the Malaysian state on the northern side of Borneo. Here, the voids are of such gigantic proportions that it’s easy to believe that you’re on the surface surveying a cliff face at night, when you’re actually deep underground in a new chamber.
Ever since the first Royal Geographical Society expedition in 1978, when a team of scientists and speleologists descended on Mulu’s forest-covered landscape, cavers have been returning to the park every two or three years. These expeditions have mapped and documented more than 250 kilometres of cave, including the largest known chamber and passage in the world: Sarawak Chamber, which has a volume of more than 11 million cubic metres, and Deer Cave, where the average height of the passages reaches 120 metres.
In 2005, I took part in a four-week expedition to Mulu during which we discovered a significant new cave, dubbed Moon Cave after the snack of Chinese moon cakes that we were eating at the time, and explored it to a distance of about six kilometres.
We also conducted the first significant exploration of Whiterock Cave, which had originally been discovered in 2003 by two British explorers – Matt Kirby and Richard Chambers – who had spent most of their stay in the jungle close to the limestone escarpment hunting for a cave known as Blackrock. They never found it, but came across a small, draughty cave that seemed to offer great potential.
The 2005 expedition took those two explorers, along with 13 others, and myself back to this cave, where numerous imposing passages and tunnels were discovered. In total, we surveyed and photographed 19 kilometres of uncharted territory.
Both caves proved too large for us to explore fully, so in January this year, I joined an expedition that returned to the caves to attempt to finish the job. Over a four-week period, team members came and went, and at one point there were 14 personnel in the field, supported by local park guides. Several team members flew in by helicopter, giving them a chance to gain a perspective on the layout of the mountains and the positions of the caves within.
Return to Whiterock
Our first task was to relocate the entrances that the teams had used during the 2005 expedition. This provided an excellent opportunity to demonstrate track-cutting skills in some seriously dense forest. Swinging razor-sharp parangs, a small group cut through the vegetation to create a rough pathway – so indistinct that it was only really apparent to those who had cut it. We tried to keep the tracks hidden in order to protect the caves from local groups who destroy delicate formations as they collect the nests of swifts, which are used to make bird’s nest soup.
Once we had found the entrances, it quickly became clear that the passages we were hoping to follow were so far inside that there was no chance of safely exploring them in a day, so we decided to camp underground for several days at a time.
We set up a base camp in the Melinau Gorge and then the following day, two teams headed out to begin exploring the two caves. Both teams were heavily laden with large packs crammed with enough food – mainly pasta and tuna – to last them several days. Luckily, they didn’t have to carry water, as it was plentiful inside the caves.
Start the slideshow (6 pictures)
A crystal maze
The five-person Moon Cave team, of which I was a part, crossed the Melinau River, north of Gunung Api, and headed for Gunung Benarat, the second in a row of three limestone mountains. When we reached the mountain, we got into our climbing gear and made the 60-metre ascent up to the cave’s entrance, which we had discovered during an attempt to bolt climb up to a higher cave located to the east of a cavern known as Tiger Cave.
Once inside, we made our way deep underground to an area where we’d seen some open passages, high up above our heads, during the previous expedition. However, after several hours battling up vertical walls encrusted with crystals, we were forced to settle for an early night back at our underground camp – christened the Geode Café – which was nestled in an alcove that sparkled delightfully when even the faintest light fell on it.
Indeed, the climbs in Moon Cave that had given us such high hopes in 2005 proved to be mere washed-out ‘solution cavities’ that only continued for relatively short distances before diminishing into nothing. The next day, however, we followed a second passage that proved to be considerably more productive.
The passage led to a heavily calcified boulder choke. After a bit of digging, it looked as if we might be able to make it through to the other side of the blockage. The ceiling was littered with sharp stalactites, and as we squeezed through, they repeatedly pierced our clothing, no matter which way we twisted and turned. This short, tight section burst into the side of yet another huge fossil passage that headed off into blackness.
With relative ease, we explored a respectable 1.8 kilometres of virgin cave, eventually reaching a point where another cave system intruded – we had connected Moon Cave (seven kilometres long) to Cobweb Cave (32 kilometres long). In 2005, we had also discovered a connection between Moon Cave and a cave known as Benarat Caverns, so in all, we had established that one of the cave systems inside Gunung Benarat is at least 50 kilometres long.
The discovery of this new connection proved to be one of the highlights of the expedition, and after three days underground, we jubilantly headed for the surface via the Cobweb Cave network.
Reconvening at camp
Meanwhile, in Whiterock Cave, the entrance to which was located about two hours’ walk from base camp, the second team managed to notch up another three kilometres of exploration in its first day. This increased the total explored length of the cave, which forms part of the maze of Clearwater Cave in Gunung Api mountain, to 29 kilometres.
The team spent the next few days exploring deeper into the cave, before they, too, returned to base camp for a rest day. These rest days allowed us to bathe in the river, eat some rather more interesting food and download survey data into our laptops.
This, then, became the pattern for the rest of the expedition. Teams would spend two or three days at a time in Whiterock– exploring new passages, filling in blank areas and establishing links between previously surveyed areas – and then come out for a rest day. We probably made half a dozen such forays over the course of the expedition.
During one such foray, one of the teams explored a major lead heading north, following it until its end – a mass of calcite and boulders just 373 metres from base camp. Unfortunately, there was no sign of any drafts, swifts or other evidence that the lead might reach the surface.
A subsequent trip to the same area uncovered another passage, 60 metres above this one that virtually duplicated the alignment of the original, lower passage. It, too, ended in calcite and boulders, this time 360 metres from base camp. This was very disheartening as it meant that, despite being so close to base camp, we had to retrace our steps back along a huge tunnel littered with boulders to our underground camp before heading out of the cave the ‘long’ way.
The final stages of the expedition were spent photographing the many discoveries underground and pushing those ‘can’t resist’ open passages at least as far as the next corner.
In all, we explored and surveyed a total of 25.8 kilometres of cave passages, including 21.9 kilometres in Whiterock Cave. The total length of the Clearwater Cave system was extended to 151.4 kilometres, confirming its current status as the world’s tenth longest.
We’re now planning to return towards the end of next year or the beginning of 2009 to continue exploring this spectacular hollow world.
Surveying caves
The most effective method for producing an accurate plan of a new cave is to ‘map as you find’. The surveying team (usually made up of three people) begins from the cave entrance or the last ‘station’ inside the cave and works its way inwards.
A station is a point of reference that indicates where you have surveyed to and where you plan to survey from. It could be an existing structure such as a boulder or a stalagmite, or it could be set up by one of the team members – a cairn of small stones, for example. The team will attempt to choose stations in passages where they can clearly see both the previous station and another suitable station farther in.
One member of the group stays at the first station, while another heads off into the blackness to the next one. The distance between stations is then obtained using either a tape measure or a laser meter. A compass is used to give a bearing and a clinometer provides the inclination between the two stations. These data are recorded in a notepad (usually on waterproof paper), and a rough sketch of the cave passage – including walls, ceiling, any obstacles and any rocks on the floor – is made on the adjacent page. At every station, four other measurements are taken. These are distance legs: left, right, up and down to the floor. It’s crucial that every measurement from a station is taken from the same place each time. This helps to create a more accurate survey once all of the data are entered into a computer program such as Survex, which combines the data to create a simple diagram of all the legs. From this, it’s possible to draw the cave to scale, both in plan and cross-section.
September 2007
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