After the Shepton's February trip we were all chuffed to have pushed Tham Pha Phueng to a new Thai depth record of -306m. However, not long after that expedition rumours started to come through the caving grapevine that another cave in northern Thailand had been explored to great depth.
The grapevine was reporting that a team of Aussie cavers and Chiang Mai enthusiasts had descended a cave somewhere in Mae Hong Son or Chiang Mai that included over 160m of pitches. Having left it like that for a couple of months I had some spare time so went Googling. Thanks to the internet and people's blogging habit it wasn't long until more details were found. Write ups of the trips can be found on two blogs by Marshall Balick
I contacted Josh and we met up in Chiang Mai where Josh kindly showed me photos and described the cave.
The cave is Tham Pha Daeng and is in Chiang Mai, with the entrance within 1km of the Myanmar border. In 2005, with Terry Bolger, Neil Anderson and Dean Smart, I had helped survey this cave to the top of the first 21m pitch where we faffed too much and didn't descend the pitch. Incidentally this was the same tour of northern Thailand on which we explored Tham Pha Phueng to the top of Fitch Pitch and, if someone is looking for a going lead, we also surveyed Tham Pha Khan in Lampang to -118m with the way on wide open and a reported lower exit. Thus Terry and I were very interested in finding out what the cave was like below where we turned round.
After the large entrance passage the cave narrows as you descend a 5m pitch and then the 21m pitch which terminated the 2005 explorations. In January 2009 exploration was continued by Marshall, Josh and their team and they descended the P21 which after about 200m reached a P40 and then a magnificent P60. This shaft is circular and the passage enters the shaft part way up - it ascends high above the window. The stream was then followed along a long narrow canyon to reach the top of a P10 at around -240m. Here they had run out of time and had to turn back.
In April 2009 Josh organised another team, which included Thai caving legend John Spies and Paul Hosie from Australia, to continue exploration. They dropped the P10 to find more narrow canyon. This ended at some smaller chambers which were home to hundreds of bats. After going through two bat chambers the passage became too tight. Back at the stream way the way on was found to be a dry flow stone bypass over a choke. The dry, mud floored passage was then followed to a P20. It had taken 12 hours to reach this point. The P20 is awkward with sharp edges and slippery mud. At the base of the pitch the cave ends after 200m where the water disappears and the mud floor hits a vertical wall. On the way out they looked at several well decorated side passages.
Everyone had been expecting to come out of a resurgence on the Myanmar side of the border, but it seems that the cave trends north-east, which parallels the border. According to the locals the water resurges near Chai Prachan which is down at the bottom of the mountains on the Thai side of the border.
The cave has only been surveyed to the base of the P21 (-99m), but after this point there are 120m of vertical pitches plus the gradually descending stream passage which would put the depth in the region of 300m. The explorers estimate the length at about 2km.
At the meeting we discussed the deep caves that had been found at Doi Ang Khang, which is a few kilometres north of Tham Pha Daeng, by a 1984 American expedition, but which hadn't been visited since. In April 2009 Josh's team had found and descended Big House Cave (known as Tham Ban Luang locally) to the sump. It matched the 1984 survey quite well, apart from some side passages that weren't shown on the survey. Although this cave is easy to get to (it is just below the road to the Doi Ang Khang Royal Project), it isn't particularly inspiring being a single boulder-floored passage that descends steeply to end at a sump. The news that other deep caves had been found in and near the Royal Project got the Chiang Mai cavers really keen and in October 2009 they found and descended Dead Robber Waterfall Cave. This is another 1984 discovery that hadn't seen a visit in 25 years. The entrance is a 67m pitch and the cave then opens up into some massive chambers.
A video of their explorations can be seen at http://www.youtube.com/watch?v=65ydpQSeHJ8
More deep caves will be found in this area....