NGUOM LUNG PHU
A team returned to Nguom Han, a cave we had connected to Nguom Pac Bo in 1997. Due to lack of time we had not investigated the left-hand passage just inside the entrance. This passage was found to be the downstream continuation of the stream which surfaces nearby and flows overland to sink into Nguom Pac Bo. The passage sumped very quickly.
The team continued to the west over a small col, where local woodcutters led us to an entrance. A small slot at the base of a cliff was found to emit a very strong warm draught. Not knowing what to make of this warm air, we descended the entrance pitch of 8m. The cave continued as a straight tall rift for about 30m to another pitch. This looked to be about 10m, but the bottom could not be seen. The falling rock test revealed it to be further than 10m. Insufficient tackle meant we would have to return the next day.
Another entrance about 50m above Nguom Lung Phu was investigated. Although a huge entrance ( 80m wide x 40m high ) the whole area was completely calcited and no passage could be found.
Returning the next day, the next section of pitches was descended. Several rebelays later the 24m pitch was bottomed landing in a large chamber. One side of the chamber led to a calcite choke, the other to a large collapse area. Carefully descending the steep slippery slope we entered a lower passage. To the west a short length of passage led to another pitch with the sound of running water below. Heading east the passage continued, a strong draught (cooler now) encouraging us. The passage floor contained large old gours, which had been covered over by a thick deposit of mud. A junction was reached with a small side passage. A quick recce and “ we want to be going this way !” As usual the promise of a streamway takes priority.
A 5m climb rigged for safety dropped us into the middle of a stream passage. Knowing the biggest potential was upstream, we set off surveying only to be shortly disappointed by a sump and calcite choke. Downstream the passage continued in fine style, although not necessitating the wetsuits we had immediately donned. Easy walking with some boulder sections made the surveying pleasant.
A large dry passage on the right was quickly checked and it’s occupant, a large green and red snake, woken up. Leaving this passage for later we continued downstream finally reaching our first swim. The draught at this point was extremely strong and very cold, the exit soon visible. Climbing up we realised we were very close to Nguom Han entrance, in a shaft which in fact was crossed by the footpath via a rock bridge. Continuing downstream, the passage soon closed down to a very low crawl, which must be within metres of Nguom Han.
Returning to Snake Inlet we surveyed cautiously and soon found our friend. We snapped a few photos and surveyed past. The passage, very well decorated, continued for 160m to a pitch into a lower passage with a large flowstone opposite. Clearly a passage we had not yet visited.
The next day we returned to descend the pitch into the upstream section of the streamway. The pitch turned out to be 13m and landed perfectly on a gravel bank surrounded by water. A quick check showed we would soon get very wet so we changed into wetsuits and started the survey. Disappointingly another sump was reached after 66m. The calcite flowstone in front was climbed but soon choked. There appears to be a much higher level, which may bypass the sump, but would require bolting. The sump was named Missing Metres. Downstream of the pitch we surveyed about 30m to a sump and calcite flow, very close to our upstream sump of the previous day.
Changing back into dry gear we de-rigged the pitch and returned to the dry passage we had abandoned previously in favour of the streamway. Kidney Stone Bypass is a lovely dry passage, very well decorated. Soon we arrived at a large flowstone and could look up into Snake Inlet. Luckily the passage continued below and we connected it through to the streamway at a junction just downstream of Snake Inlet.
Lung Phu is 1.7km long and 81m deep. The length of the streamway Ban Cong Freeway was 600m. There is potential for 2 to 3km of cave from the upstream sump to the sinks marked on the map. The next trip will attempt to find a way in from the sinks.