New Deepest Cave In Thailand

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 The recent Shepton Mallet Caving Club expedition explored a cave in Nan to a new Thai depth record of -306m. This blog entry records this successful trip.

As is traditional the 2009 Shepton Mallet Caving Club expedition met up in the Cowboy Bar, Ayutthaya. Jet lag was cured with copious amounts of beer and the team gathered, suitably refreshed, the next morning for the drive to Lom Sak.
 
As a gentle introduction to Thailand the two newbies, Jo and Andy, were led on a little walk in the woods to look at ‘Cave 26’ near Tham Yai Nam Nao to the north of Phetchabun. A sweaty two hours after setting off the team arrived at the cave. Unfortunately it was sumped after about 150m, but it is still a promising site as it is the furthest upstream cave known in the Tham Yai Nam Nao system.
 
Our final expedition member, Terry, arrived by bus from Laos in the afternoon in time for that evening’s entertainment – a merit making party for Martin’s house. The cavers were also on time, but only managed this by dragging a grumbling Phil back from the walk without a stop at his favourite noodle and beer shop. The party was enjoyed by all with dancing being compulsory, though I’m not sure how Terry managed to end up dancing on the stage with the singing girls.
 
Following this evening of excess the following day was spent taking in a gentle tourist trip to Tham Yai Nam Nao. As is often the case the visit stopped at the ‘CO2 Sump’ where the carbon dioxide meter went off scale at 7%. Meanwhile, back in Lom Sak, Martin and Terry got in the way of the ladies preparing the consumables for the week long trip to Nan. Of great importance was checking that enough beer was purchased.
 
On the morning of Wednesday 11 February the two pickups were overloaded with caving and personal kit, two ice boxes of food, sleeping bags, camp beds, cooking utensils and 8 boxes of beer. It was a long day’s drive to get to our base in Ban Mani Phruk, northern Nan province. The 530 km took some 7 and a half hours. On arrival at the Security Development Project headquarters (which despite the name is more of an agri-tourism project) we soon settled in.
 
Day One and we were keen. Everyone was planning on a trip to the main target of the expedition – Tham Pha Phueng. This cave had been explored in 2005 to a pitch down which stones fell for 5 to 6 seconds with an awesome ‘boom’. A 200m rope had been kindly purchased by the Shepton Mallet CC to allow us to tackle the pitch and one group packed their spits, hammers and rigging kit. The second team intended to survey a passage that headed in a different direction from the foot of the small first pitch and hadn’t been looked at in 2005.
 
Tham Pha Phueng is only a kilometre north of where we were staying and even more conveniently it is a mere 2 minutes walk along a good path from the road. From the large entrance the cave descends steeply down boulders with occasional flatter areas. No one seemed to take the same route twice up and down this passage. At -97m the passage narrows and you reach the first pitch. As it is only 7m it was rigged with a ladder and lifeline. At the foot of the pitch the A Team set off down the main passage to the big pitch (which is at -163m). Team B started the survey in a big fossil passage with an underfit stream which became a narrow vadose canyon. After scrambling down a couple of 2m cascades and wading across a couple of pools we reached the head of a more serious 3m drop. Whilst faffing around rigging a rope we were slightly surprised when Team A appeared at the foot of the pitch. Despite all their preparations the cave spirits had hidden the spits so they were unable to start the rigging. Instead they investigated the vadose canyon inlet explored in 2005 and timed it well to arrive at the bottom of the climb that stopped the 2005 group at the same time as Team B arrived at the top. Some of the group did an exchange and the two parties headed on out the cave.
 
Day Two and the keen Team A (Jo, Andy, Terry and Paul) went back to the big pitch in Tham Pha Phueng – this time with plenty of spits. Team B went by 4x4 for a bit of surface prospecting to the south-east of Ban Mani Phruk where several dolines and a couple of sinking streams are shown on the map. Team A managed to install the spits and rig the rope at the top of the pitch and also rig a traverse round the top of the pitch to a large inlet passage with a very fine set of gours. Team B parked the car on the ridge and walked down into the bottom of the doline of the Huai Poen stream. By following a dry stream bed they found the sink, where the stream drops into a cave via a rift with a 3 second drop. Whilst walking back up to the car a local farmer pointed out they were daft to have parked at the top of the hill (a conclusion most of them had already come to) and that next time we should drive down.
 
Day Three saw everyone back in Tham Pha Phueng. The keen Team A (Jo and Andy) continued rigging the big pitch, reaching a ledge about 20m down. Team B (Phil, Tiggy, Paul, Terry and Martin) surveyed up the Gour Passage which reached a breakdown chamber (with an unexplored muddy inlet) and then became a vadose canyon. This was ascended until a 3m climb. Although Paul got up the climb he had some fun getting back down so the survey was stopped at this point. This vadose canyon is heading towards the main entrance boulder passage as it is thought that it will probably come up underneath these boulders.
 
 
Day 4, Sunday 15 February, was a ‘rest day’ where no one went underground. Terry had a solo walk to look at some dolines to the east of Ban Mani Phruk while Jo, Andy, Paul and Tiggy walked downhill to the west of the village to look for possible resurgences (the resurgences for the plateau are not known). Phil and Ivan had an epic walk to the doline to the south of the Nam Dan valley. They took the easy option of walking in via the road and farm tracks, but decided to cut across country to get back. By the time they had taken 3 hours to walk a kilometre they realised this was a mistake.
 
Day 5 – back to the caving. In Tham Pha Phueng Jo, Andy and Paul rigged across the traverse at -20m on the big pitch while Tiggy and Phil took photos. Back near our base Martin, Ivan and Terry surveyed Tham Nam Dan which unfortunately became blocked with boulders after 100m. Terry and Martin looked at the huge boulder pile where the Nam Dan stream sinks and although a cold breeze could be felt no way in could be found. Also of interest on this day was our Hmong neighbours sacrificing a pig to appease the spirits. This seemed to work as the cave spirits stopped hindering our work, though Jo says they still talked to her while waiting at the top of the pitch.
 
Day 6 was to be the day when the big pitch was descended. Jo, Andy and Terry went in and Andy was the first down the pitch. After derigging the rope was measured and the pitch was found to be 125m deep with a 109m free hang from the traverse ledge. This big pitch has been named Fitch Pitch in memory of Terence Fitch, a Shepton member who died in 2008. At the bottom the pitch lands in a 30m diameter chamber. There are three ways off to the south of the chamber. One is taken by the stream, the middle one soon joins the stream while the eastern exit loops around to a point opposite the middle route. Both these routes stopped at the top of 3m gour climbs where the passages join. The way on could be seen to be a large vadose canyon heading north-west. Back on the surface Ivan, Phil, Paul, Tiggy and Martin went for another walk into the Huai Poen doline which had been first visited on day two. This time they took the farmers advice and drove most of the way into the doline. By heading north along tracks and paths they reached the Huai Poen stream which was then followed to were it went over a 20m waterfall into a huge collapse doline. A path lead around to the other side of the collapse where a large cave entrance could be seen. Only Ivan was brave/foolish enough to scramble down the very steep slope to be able to look into a huge cave passage. Unfortunately a short slippery slope and lack of handline prevented him getting into the cave properly. On the walk back to the car Martin, following the GPS which said the track was less than 50m away, led an epic bit of bushwacking through razor sharp cane and grass and eventually collapsed on to the track. Ivan and Phil, who had learnt their lesson on Day 4, wisely hung around at the back to allow the path to be beaten down for them.
 
Day 7 was the last day. Jo, Paul, Tiggy and Ivan went into Tham Pha Phueng in the morning to derig Fitch Pitch and the traverse to Gour Passage. In the afternoon Andy, Terry, Phil and Martin headed down the cave to help carry out the sacks and derig the ladder. By 16:30 everybody and everything was out of the cave. That evening we finished off the stock of beer and sampled some of the local sticky rice moonshine whisky. Although smooth and drinkable this whisky was regretted by some the next day.
 
Tham Pha Phueng surveys: Plan  Projected section

So that was the 2009 Shepton Thailand expedition. It successfully achieved the objective of descending the big pitch in Tham Pha Phueng making it the deepest known cave in Thailand at -306m with the cave continuing. In addition Fitch Pitch is the biggest pitch descended in Thailand. We also found two other caves that haven’t been descended, but have the potential to be as deep Tham Pha Phueng. This was achieved by a team with limited experience of exploring and rigging big Alpine caves, in particular having to hand drill the spits (a total of 12 were placed) as we didn’t have a battery drill. Jo and Andy were especially keen on their first trip to Thailand and went into Tham Pha Phueng every day except for the ‘rest day’. Plans are already being made for a trip next year.

We would like to thank those people who made this a successful trip. Yuphin Sopha organized the cooking equipment, food and booze, Eng Prommaviang did the cooking and Nom Hollis helped with cooking and shopping – without this ‘base camp staff’ of three, who made trips down the hill to restock with food, beer and ice, this expedition would have been a lot less fun for the cavers and their hard work is much appreciated by all of us; Yook for allowing us to use her cooking and dining facilities at the Project headquarters; Mr Phinit, Head of the Project, for allowing us to stay in the guest rooms free of charge; the Hmong villagers and farmers of Ban Mani Phruk for allowing us to wandering around their fields. A thank you also to the Shepton Mallet Caving Club for purchasing a 200m rope and CO2 meter as well as supporting previous Thailand expeditions which has resulted in a well stocked tackle store.

The cavers: Terry Bolger (Canberra SS), Jo Campbell, Phil Collett, Paul & Tiggy Dummer, Martin Ellis, Ivan Hollis and Andy Manners.