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Vietnam 97

The Fourth Joint British/Vietnamese Caving Expedition (Phase One).

By Snablet


The expedition was split into two phases.  Phase 1 would take place over 5 weeks, with aims of continuing the work carried out by the 1990, '92 and '94 expeditions within the Troung Soan Massif of Quang Binh province.  The plan was to continue exploration of the Hang Vom cave systems and to locate and explore the top sinks to the Phong Nha cave systems.  Phase 2 would take place over 2 weeks and continue the work carried out by the 1995 reconnaissance trip Cao Bang province.  We were joined in our expedition by cavers from the Geological Department of Hanoi University and local villagers.  This write-up covers the first phase of the expedition, as it was the phase I took part in.

Banged up in Ban Ban

Hieu (Hanoi University) stunned the snake with his Vietnamese - English dictionary - giving proof to the saying "the word is mightier than the sword".  Dr Phai (Hanoi University) grabbed the dazed snake and flung it overboard.  The six wheel drive Russian truck had just driven through another overhanging tree, causing the contents of the tree to shower down on us.  Normally this causes us Western cavers to nearly jump out of the truck in fright of the slithering, crawling and wriggling creatures which fall from above; this in turn, causes great hilarity amongst our local guides and porters.  This time however, it was the locals who were on the verge of jumping out of the truck ahead of us, "it must be dangerous this time".  The journey up the Ho Chi Minh Trail was incredibly rough; the high clearance Russian trucks (used for the haulage of rattan) would regularly ground out along the deep ruts.  The journey is also cramped, half the truck is full of rice, diesel, rice wine and cabbages the other half is filled with 16 people and caving kit. The drive along the trail is broken up by regular stops, mainly due to breakdowns of other rattan trucks as well as ours, but also for lighting joss sticks at every shrine and sale of rice wine to all the other HCM trail users.

We dropped off the Hang Vom team at Kilometre 24, a mere 4 hours from our base camp in Son Trach (Kilometre 0).  The team consisted of Howard Limbert (N.C.C.), Martin Holroyd (N.C.C.), Paul Callister (N.P.C.), Andy Mackie (N.P.C.), Dr. Vu Van Phai, local porters and guides.  We would try to arrange a truck back to meet them in 5 days.  The rest of us, Deb Limbert (N.C.C,), Simon Davis (Croydon Caving Club), Trevor Wailes (Tasmanian Cave Club), Nguyen Hieu and I, travelled on a further 4 hours to the village of Ban Ban at kilometre 48 where we encountered a sign reading (in English)  "Frontier post, restricted area". We were promptly placed under arrest by members of the local garrison.

We were accommodated in the local hospital (The Ban Ban Hilton).  It did have bars (on the windows), although the doors were not kept locked.  We were given instruction as to what we could or could not do, whilst we waited for a decision from Hanoi High Command as to whether or not we would be allowed to proceed onto the top sinks or whether we would be allowed to go home, for that matter. Ban Ban is an extremely idyllic village populated by the very friendly minority Ruc Caroong tribe.  During our 5 day enforced visit, apart from playing a lot of cards, we were invited to a festival of tradition: drinking, traditional music and dancing interspersed with music by Boney M.  We also discovered a bar in the village and providing we were granted permission to cave in the area (we were) the hospital would make an excellent base camp.

Reece to the Top sinks

Jungle walking in Vietnam is always entertaining. If a path exists it will always take the steepest, most direct route to the top of every hill, followed by an equally steep route down. Paths never seem to follow the contours or valleys.  The reason behind this is because the extremely valuable perfume tree only grows on the tops of the highest hills, and the majority of paths that lead into the jungle, go in search of this elusive tree.  (We will have to convince the locals that perfume trees grow by cave entrances).  Personally I reckon our route has more to do with our guides wicked sense of humour. Once, we swapped our 70-litre rucksacks with those of our guides.  Miraculously, paths that avoided crawling under branches and tracking up to the hilltops suddenly emerged.


Hospital in Ban Ban - our Prison for a week and base camp for the rest of the expedition. Photo - Snablet

Three and a half hours into our trek from the hamlet of Ban Ban, we arrived at a sizeable river called Khe Rhy (Grass Stream).  Downstream, in the distance, large limestone cliffs loomed several hundred metres out of the forest; this was the southernmost edge of the Truong Soan Massif. A brief break was taken to enable the extraction of a dozen or so leeches from our boots (leeches don't seem to like water, the deeper the water gets the higher up the body the leeches go). After consultation of our map, we presumed Khe Rhy to be the second top sink for the Phong Nha and Hang Toi systems. If our theory was right, Khe Rhy stream sank at the 'limestone/other type of rock boundary', i.e. the base of the cliffs.

After 1/2 hour of slippery cobbles and falling into the river we arrived at an insignificant sink. A small entrance could be seen, but it didn't inspire us with confidence.  However, a large dry riverbed continued along the base of the cliff. "Maybe there is a flood entrance" - there was.  The entrance of Hang Khe Rhv was of similar proportions to Peak cavern and led off into the cliff.  Our hopes were high.  The active sink was effectively acting as a sieve for this impressive fossil entrance. We hoped that this would prevent the cave from being blocked with forest debris.  Our previous day's experience at the first top sink, when all we found was large log chokes was still fresh in our mind.

"Yoh! Exploration time!"  However there was a small drawback.  On our journey along the HCM Trail from Son Trach to Ban Ban, one of our large tackle bags mysteriously vanished (not stolen, of course, because theft doesn't exist in communist countries).  Unfortunately the bag contained our rope, medical kit and a week's worth of carbide. The remaining carbide was rationed (two carbide lights today and two the next).  Caving along 40-50m wide passages strewn with slippery cobbles on a Petzl gloom is not the easiest of tasks. Simon, Trevor and I surveyed our way in, whilst Deb checked out all the possible leads and the way on.  The entrance series consisted of a wide, meandering bedding-type passage dotted with deep, static pools and cobbles.  I encountered my first bit of Vietnamese wild life (other than several species of leeches and the snake, that is) whilst walking backwards preparing to read off another 50m tape length: my feet where thrown from beneath me and I nearly shat myself.  After much panicking and cursing, I managed to disentangle myself from a 1½ m long by 200 mm thick eel, which I had just stepped on (later, when I told our local guides about the eel, they instantly organised a hunting party and worried whether their pot would be big enough).  800m into the cave, we encountered a T-junction through which the main stream flowed.  We chose to follow the upstream passage, which led past numerous gours, stal and the occasional column.  We deduced that the water (approx. the same amount as in OFD) must have come from the first top sink (Khe Roung).  Upon reaching a long swim we decided to retire back to the entrance camp with 1.8 km of great passage in the survey book and no ends in sight.

Hieu in Back Passage - Hang Khe Rhy.  Photo Howard Limbert


Jet Highway - Hang Khe Rhy. Photo - Howard Limbert

Later, back in camp, we encountered a slightly bigger version of Vietnamese wildlife.  We were awoken by a commotion of shots being fired into the air, pots and pans being banged, and shouting.  Within seconds, a fire worthy of any Guy Fawkes celebration was built and ablaze.  There was a large Ho (tiger) in the camp, and our Vietnamese friends were rightly worried, for in 1992 a tiger had attacked, maimed or killed seven local villagers. The tactics adopted by the cavers was to pull their bivi bags over their heads and hope it would go away.  We moved camp the next day and went in search of the third sink, leaving the exploration of Khe Rhy for a return visit. The third sink was reached by mid morning. Khe Thi, a similar sized stream to the first and second sink also sank into the base of large cliffs.  Hang Khe Thi consisted of a scramble down some large boulders to a lake. Deb investigated the lake to no avail, it turned out to be a large sump pool.  We spent the rest of the day scouring the valley in the hope of finding another entrance.  We camped the night on a boulder pile within the cave surround by two bonfires to ward off any oversized cats.  The following day consisted of a 7 hour walk back to Ban Ban.  The walk did not do much to inspire us to visit the fourth sink; reputed to be a further ½ days walk from the third sink.

Upstream Hang Vom

At kilometre 24 down the HCM trail we rendezvoused with the other team: Howard, Martin, Cal, Andy, Hieu and guides etc. and listened to their tales of caverns measureless. Their first outing into the jungle under the guide of 'Jungle Jim' led them on a wild goose chase in search of Hang Dau Cao.  Eventually, after 2 solid days of trekking through the jungle, their guide admitted that he had never been to the caves before in his life.  Phai saved the day and found the top entrance to Hang Vom. This meant that the rest of the Hang Vom hydrological system had to be traversed (5 caves) to get to the 1994 limit of exploration.  A logistical epic ensued to get 1 guide, 3 porters, and our local committee representative through the cave systems, one of which included a pitch.  Martin became a human cross-channel-ferry, taking non swimming guides, porters and equipment across the many lakes and canals within the cave systems.  The first excursion located and explored Hang Ho (tiger cave) and discovered the entrance to Hang Over. Ironically, the journey from the far caves back to the Ho Chi Minh trail took no more than 2 hours.

Hang Ho: The entrance had been located and the first 200m explored by the 1992 expedition.  The cave was now fully explored and resulted in 1.6 kilometres of superb cave.  Time restraints meant that upstream valley from "Total Internal Refraction" was left unexplored and would lead to more kilometres of passage within the cave, sighted in the distance.  The main route of exploration was along "Monster" passage to exit by "Swift Exit", 100m up the valley led to the entrance of Hang Over.

Hang Over: was explored on the second excursion into the jungle; it was named after Dr. Phai's session on the rice wine, to relax from his negotiations with the army.  Another huge cave, 3.25 kilometres long with passages between 30 to 125m wide.  There is still a possibility of further passage at the bottom of "The Chasm" (un-descended pitch, approx. 25m deep).  The exit from Hang Over enters a doline; Hang Pygmy continues on the other side.

Hang Pygmy: The proportions of this cave made the caving team feel like pygmies.  The 90m wide passage leads past an abandoned village used by locals for harvesting nests from the cave's swiftlet colony. The cave is 845m long and all lit by daylight from its two entrances.  This cave must be close to the village of Ruc Caroon, near where the top sink for the Hang Vom cave systems is located.

The Hang Vom Hydrological system now consists of ten caves interlinked by dolines and limestone gorges. At present, it would be possible to traverse the system from Hang Pygmy to Hang Vom, however, Ruc Caroong is not (yet) connected:




Ruc Caroong (Top sink)

Hang Pygmy

Hang Over

Hang Ho

Hang Watermelon

Hang Dany

Hang Ca (Pitch Cave)

Hang Duat (Maze Cave)

Hang Dai Cao

Hang Vom (Resurgence)





















R & R

For rest and recreation between trips to explore remote caves in the middle of the jungle, we decided to take a couple of days off.  We filled our time by exploring caves at the edge of the jungle.

Vue Tro resurgence valley - a reece. Photo - Snablet

Vue Tro resurgences: Over the course of a couple of days off, 5 entrances were located, all bar one of which either choked or sumped after a short distance.  The cave, which still has some possibility of revealing more passage, was left at the start of a deep and long canal due to lack of swimming equipment.  The locals in the area told us of a large entrance with a beautiful lake within the cave.  Unfortunately, this cave proved elusive despite many hours of searching.

Hang Len Hai Thone Tin (Information Cave): This cave was located within a karst tower at the edge of Son Trach village. The cave was used during the war as a radio relay post and a gun emplacement.

Cha Noi: Motor bikes and taxis were hired to get us as close as possible to the village of Cha Noi (our map showed three sinks at this village).  Unfortunately, we were still left with a 9 kilometre walk to get there.  This resulted in a considerable lack of time to get back to our taxis before nightfall (no lights on the bikes).  We were shown to a fossil cave near the village, which had been used to house an army regiment during the war.  Our time to check out the resurgences ran out. Both Information cave and Hang Cha Noi proved to have very little potential for major cave finds.  However, they do give an insight into the harsh conditions that the Vietnamese people endured during the course of the war.

Motor Cycle recce trip - Ferry across the Son River at Sin Trach. Photo - Snablet

Khe Rhv

Dwindling medical supplies and the extreme remoteness of Hang Pygmy necessitated that the whole team would return to Khe Rhy for a final week-long push on the system and surrounding area.  We hoped that we had not put all our eggs in one basket, only to find ourselves Ghar Paraued around the next corner.

Whilst our local guides, party officials, and army observers entertained themselves making pangolin pie, monitor lizard hot pot, snake casserole and drying 5 kilos of fish a day, we split into 2 teams and systematically explored, surveyed and photographed Hang Khe Rhy.  The cave has everything you want for a tropical expedition.  Its main drain is huge, interspersed with pristine gours, chandeliers, columns and bosses.  It is mostly stomping passage with the occasional long swims, which are interrupted, by cobbles/sand banks, allowing welcome rests.  There is hardly any crawling and only one boulder choke (although it is 300m long).  Hang Khe Rhy so far consists of 10 kilometres of superb river passage called the Ho Chi Minh Trail, which we left wide open at the start of another swim.  Water can be heard flowing over rocks in the distance. We were worried at one point that we had reached a sump (Sump or Glory) after 250m of swimming along a huge passage the roof lowered to only 1.5m.  Luckily it opened up again into a big chamber.  The "Sump or Glory" is the main danger area within the cave. Prior to its discovery, we had encountered a substantial rise in water levels due to rain in Laos.  This made traversing the river passage extremely sporting and hearing survey readings almost impossible.  There are 4 kilometres of well-decorated side passages and inlets, one of which reaches an upstream entrance (Foot and Mouth). There are 3 unexplored side passages in the far reaches of the cave, two of which are so vast they completely dwarf the 40 x 30m river passage, it is like walking out of the cave into the open air on a black night (it was midday, by the way).

Andy in the Pseudo Inlet GOUTS - Hang Khe Rhy. Photo - Howard Limbert

The continuation of the main river passage and the huge side passages is the main objective for the next follow-up expedition.  Khe Rhy's present length of 13.8 kilometres makes it the second longest cave in Vietnam; it has travelled approximately 3 kilometres out of 16 towards its possible resurgence.  Along its route it has picked up three major sinks and there are still the two biggest sinks to find, our hopes are high.

The Rescue

Just before the end of the expedition, Trevor and Cal decided to undertake a 2-day recce of the fourth sink known as Khe Tien (beautiful stream).  They were accompanied by Hieu, Mr. Cuoi (the most highly acclaimed hunter in the district) and his dog.  Late the next day, whilst we were preparing to move camp from Khe Rhy back to Ban Ban, and just after we had burnt the remaining dried food and carbide, Hieu and Mr. Cuoi arrived back at camp alone!  It turned out that Cal and Trevor had entered the cave the previous afternoon.  Soon afterwards, a flood pulse came down the river, washed away their camp and trapped the two lads inside.  The weather had been great that day, hardly a cloud in the sky.  The river flows from some mountains deep within Laos, it must have been raining there.

We had a horrendous walk for 5 hours most of which was in darkness with no trail, to arrive to see the river still heavily swollen, and the remains of their camp scattered through the cave.  We spent a sleepless night by the entrance being eaten by leeches and mosquitoes. At first light, when the river had dropped sufficiently, we searched the cave with trepidation and found it very aqueous, it ended in a lake in a final chamber with no obvious ways on: "this must be a sump".

We dammed up and diverted the river down another sink, we dammed the cave and bailed the sump, and Martin attempted to find and free dive the sump - but all to no avail.  Our only option was to wait.  Whilst waiting we constructed more dams (in case of further flooding) and conducted hourly checks on the sump.  A message was sent back to Phai in Son Trach, with our guide informing him of the situation and to prepare for a rescue.  Howard decided that we would wait another day to in the hope that the water would drop, if it didn't Rupert Skorupka and Tim Allen along with diving kit would be flown out from the UK.

Fifty-seven hours after Trev and Cal became trapped; Simon and I wandered into the cave for the 4am check on the sump level.  We noted that water levels had dropped significantly since we were last in.  As we entered the flooded chamber, we could see a faint glow through the water accompanied by the sound of water gulping, "Yoh! There's air space!"  We both dived through and met Cal and Trevor, sitting in a dry chamber underneath a daylight shaft on the other side.  It was a great relief to find the two lads alive.

We shared a packet of 'Super Noodles' and two Mars Bars between the ten of us, and set off on an 11 hour slog back to Ban Ban.  Along the way we met a detachment of the Vietnamese army, equipped with picks, shovels, medical supplies, food and cigarettes coming to our aid (they were a very welcome sight).  We got back to Ban Ban to an emotional welcome, had a swift half, bid farewell, and hopped on our truck.  This took us back to Son Trach by 4 am the following morning, whereupon we had another swift half, our first food for three days and three hours sleep before catching the 8 am bus to take us to our train back to Hanoi.  We eventually reached Hanoi late the next day, tired and thin.

Synopsis of caves explored by Vietnam 97



Cave Name




Vert. range

Phase One - Quang Binh Province




Hang Ho

Thuong Trach

Bo Trach



Hang Over

Thuong Trach

Bo Trach


103m( +93,-10)

Hang Pygmy

Thuong Trach

Bo Trach



Hang Khe Thi

Thuong Trach

Bo Trach



Hang Khe Rhy

Thuong Trach

Bo Trach


12Om( +58,-62)

Hang Khe Tien

Thuong Trach

Bo Trach



Hang Cha Noi

Cha Noi

Bo Trach



Hang Len Hai

Son Trach

Bo Trach




Phase Two - Cao Bang Province




Nguom Boc Rising

Ban Nua

Nuoc Hai



Nguom Boc Sink

Ban Nua

Nuoc Hai



Nguom Pac Bo

Soc Quan

Ha Lang



Nguom Han

Ban Cong

Ha Lang



Nguom Muong

Ban Thuoc

Ha Lang



Nguom Ram

Ly Quoc

Ha Lang



Nguom Ron

Ban Cong

Ha Lang



Keo Min

Na Dang

Ha Lang



Nguom Khu

Minh Long

Ha Lang



Nguom Khoung

Minh Long

Ha Lang



Nguom Sap

Ban Sa

Ha Lang


31m( +23,-8)

Nguom Ban Khau

Ban Khau

Ha Lang


+ 13m

Nguom Gio

Ha Quang

Ha Quang



The joint British/Vietnamese expeditions have so far explored and surveyed 101.5 km with 35 surveyed caves totalling 72.5 km within the Bo Trach district of Quang Binh province and 72 surveyed caves totalling 29 km in other provinces.


Bradshaw, D.R.1990. Vietnam 90, British Speleological Expedition.

Callister, P. 1997. Fe, Phai, Ho, Hum, A Tale of Vietnam. Descent.. 137 (AuglSept): p28 - 30.

Holroyd, M. 1997. Vietnam 1997. Caves and Caving. 77 (Autumn): p27 - 31.

Limbert, H. 1997. Vietnam 97. International Caver. 20: pll-18.

Limbert, H. et a1. 1994. Vietnam 94, 1992/94 British Vietnamese Caving Expeditions.

Limbert, H.  et a1. 1997. Vietnam 97, Joint British / Vietnamese Caving Expedition.