HANG KHE RHY
Hang Khe Rhy was first explored by the 1997 British Vietnamese Expedition. The entrance is located on the edge of the limestone, to the south of Hang Phong Nha. In 1997, the cave was explored and surveyed for a length of 13.8K. The main entrance called Cool for Cats after a nighttime visit by a tiger is a flood overflow. The inlet passages for the Khe Rhy and Khe Thi streams have been located inside the cave. The cave is a major river cave and forms one of the main feeders to the Phong Nha System.
In 1997 the exploration was left as time ran out, with the main river passage still wide open. The return trip this year hoped to continue the exploration towards Hang Tung, the next section of cave in the Phong Nha system.
A team of seven cavers, including Mr Nguyen Hieu of Hanoi University entered the cave for a three-night camp. The length of the cave after the last expedition meant a camp was necessary to push on downstream. The team entered the cave at midday, having walked from the nearest village of Ban Ban. The local people of Ban Ban assisted in carrying the equipment to the entrance. About five hours of caving followed, until the team had passed through Sump or Glory (a low arch at the end of a 250m swim) and 5km of passage. All the equipment had been tested for waterproofing in the river at Son Trach the day before. Not all bags were successful in the river, but thankfully underground everyone’s gear made it to camp nice and dry.
There were no obvious camping spots, so the Thousand Yard Stare was checked and found to be a dead end. Camp was eventually made on a shingle bank, with a bit of protection from the draught. After the previous expeditions, we knew we could not survive on My Thom (noodles) alone, tasty though they were, so we had brought a selection of ready meals made by Wayfarers. These proved really excellent and a good treat at the end of a hard day. The breakfasts also sustained us really well for a full day’s caving.
After an early night - an early start the next day. A team of four proceeded to take photos around camp and further downstream, and check side passages. The remaining three set off with their gear to reach the previous limit, push on and hopefully find a good camp for the second night.
The last surveyed point, What You See is What You Get, (when its 50m wide you know its going to go) was reached after traversing over a kilometre of boulder choke. The next camp therefore had to be after this. Passing ‘What You See’, the team continued for about 500m until a marvellous campsite was reached. A huge sand bank on a bend, with loads of space, well above the water, and out of the draught. A dry side passage was also seen. The team dropped their camping gear, had a brew and set off surveying. The camp was ringed with Darren drums so the following team wouldn’t miss it. A cryptic note was also left suggesting that they might prefer to catch the survey team up and push on downstream, rather than bag the nice dry side passage.
The next section of passage was almost immediately a swim of a couple of hundred metres. Many small white fish were seen here. Another low section with a howling draught and the cave opened up again. The passage continued with plenty of swimming and some bouldery sections. A couple of bends followed, and then a climb up onto a huge flowstone formation. The top of the flowstone was formed of many large mostly dry gour pools. Traversing round their narrow rims around the deep holes was like traversing around crevasses, so this was named the Mer du Glace.
Unfortunately at this point we could see daylight, which was disappointing, although it was a further 500m before we reached the entrance. The river disappeared amongst the entrance boulders. Climbing out there was lots of evidence of local people, including a hand knotted vine hanging down a 50m shaft just inside the entrance. We could see limestone cliffs in the distance, and low cloud and rain. The team made a brief reconnaissance but realised they didn’t have time to achieve much, and so returned. An additional 1.9km had been surveyed. Back at camp, the photo team had bagged the dry side passage, as they didn’t have time to catch the survey team, hence Disobedience Passage. A good night was passed at the camp,” The Good the Bad and the Vodka” with more nourishing food to accompany the alcohol.
The next day, the bad, set off for the exit, Huda Thought It, to try and find out where it was and if there was any continuation. The good set off to survey a side passage, which seemed to be going, arranging to meet up with the vodka back at camp one.
Reaching the exit, the team followed a path, which led to another huge entrance. Meeting up with some woodcutters, Hieu was able to ask them for information. It seemed this was Hang En, a short section of cave, which had been explored in 1994. Unfortunately this meant the exploration was probably finished in this area, as downstream had been checked out and found to be a massive impenetrable logjam. The combined water of Hang Khe Rhy and Hang En joins at this point to form the full Phong Nha water.
The survey team continued to Mendip Head passage, a smaller than average side passage. Initially a gour slope, the passage developed into a mud floored abandoned streamway. Easy going apart from the mud, the team was surprised to see their team-mates footprints continuing after several hundred metres. The motto for caving in Vietnam is no pushing without surveying!
After a second acute bend, the passage opened into a breakdown chamber with fine formations. The way on continued over slabs and into a smaller section of passage, finally leading to a crawl over mud and then boulders. Determined to make the most of what could be the last trip into Khe Rhy, the virtuous survey team pushed this uninviting lead. The reward was to emerge into larger passage, which soon dropped into a large abandoned passage going both ways.
Yorkshire Way was followed in the ‘downstream’ direction first. This is a very old passage, with remnants of gour dams and very sharp water worn limestone. Disappointingly after 200 metres the passage ended in a huge collapse chamber. There was no obvious way to proceed, and the climbing options looked too risky.
Returning to the T junction, the team surveyed ‘upstream’, initially a fine passage with gour floors, the roof soon lowered leading to stooping but thankfully no crawling. After about 400 metres, the passage ended at a small pool surrounded by formations. A calcite blockage stopped further progress.
Once the survey was drawn up, it was obvious that the two ends of Yorkshire Way are very close to the edge of the limestone, with no further potential. Tired but with a good days surveying (another 2km) the team continued to camp.
Returning from their excursion to the outside world, the others announced that it was raining, but had been doing so every evening since we’d entered the cave. Since we had not seen any increase in the water so far, we felt safe in camping and exiting the next day. Tiredness, hot coffee and dry clothes also contributed to the decision. The next morning the water had risen a few inches, but this presented no problem, and the team made a safe exit.
The total length of Hang Khe Rhy now stands at 18,902 metres, the longest cave in Vietnam. The water from the Hang Khe Tien entrance is not seen in Khe Rhy, and must join the system via a separate route. There is potential for 3-4km of cave from this entrance. This brings the total surveyed length of the Phong Nha System to 40km.