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 Hang Mo

Near Thai Minh in Tien Ky District, Nghe An Province. Explored by Adam, Snablet, Mr Tu, Howard Clarke and Peter Whitaker. 13th and 15th April 2007. Write up by Peter Whitaker.

Summary – a fine river cave mostly in a railway tunnel sized passage. In the dry season the stream is very slight. The cave is easy going and mostly sandy floored. It had recent bare footprints along most of the length of the main passage, probably from a local hunter. Of all the caves in this district, this had the most potential for tourism, although there were no easily accessible splendid formations. It is more of a “tourist cavers’ cave” than a “tourist cave”. Its beauty was in the fine tunnel passage and colony of bats. Visitors must be capable of some basic scrambling as there are large boulders near the entrance to be negotiated.

 This cave was the first we explored in the expedition’s first visit to this district.After getting the go ahead from the province authorities, we visited the Tien Kydistrict headquarters. This was promising from the outset, as there was a largekarst feature in the central fountain. The officials were keen to show us photo’son the wall of a committee day-trip to look at scenery and caves; they asked uswhich cave we wanted to visit first. We pointed at the series of photos showingthem crossing a pretty meadow and entering a decorated cave and indicated thatwe would like to survey that one first. A bustle of activity within the committeerooms followed – comrades were gathered from stuffy rooms at the prospect ofaccompanying us on a boys jolly. It really did turn out to be a boys jolly - a girlclimbed into their jeep and was pushed chauvinistically back out; the space wasrapidly filled by another male committee member. 

We followed the committee jeep from the town, through villages in the country to the eventual turn off the road onto a farm track. This continued flat for a few hundred metres until it reached a stream. As we donned the caving gear, the committee men got into the swing of things. They passed around alcohol and the atmosphere got more jovial. The cave was a very short distance up the stream from the road; this stream issued from the cave entrance; stream level was blocked by boulders, so access was easily gained by climbing over the boulders to drop back into the stream.The route into the cave soon came up out of the stream to pass over the top of a boulder choke; which showed recent evidence of people – candle wax, glass and food wrappers were present. This boulder choke lasted for around 35 metres, before dropping back down to the stream. We were now in a sandy tunnel, around 3 metres wide, with a small stream running along the bottom. We could follow a single pair of footprints. Peter scouted ahead; Snablet drew, whilst Howard and Adam operated the survey instruments. The committee men were having a real adventure, keeping up with Peter and enjoying their day out of the stuffy committee rooms. When they realized we were in it for the day, they exited to the nearest café with Mr Tu to spend some miscellaneous expedition money.

The surveying continued for over a kilometre, with the character of the cave remaining the same – a large phreatic tunnel, sparsely decorated, with pebbles and sand on the floor. The going was quite easy and we followed a single set of footprints throughout. There were notably many bats roosting in the cave; Peter particularly noticed them when, whilst surveying through a constriction, one flapped past and used his face as a springboard for a floppy, leathery winged exit.

 Upstream in the main passage continued in the form of the railway tunnel, although it was noticeably smaller since the junction. It did contain some long survey legs, in the order of up to 65m, made possible by our laser surveying equipment. This main inlet yielded just over 710m of passage to its  conclusion. At parts, where the shape of the passage altered at corners, the bats had taken good advantage of this and used its secluded nature for roosting. The smell of guano among the humidity here was overpowering and it was around here that Peter had his encounter with a bat whilst in a constriction. The constriction seemed a good place to leave the surveying that day. The team returned 2 days later, but without Snablet who had gone back to New Zealand. Mr Tu capably accompanied the team and made himself very useful, during the exploring, surveying and photography.Continuing the surveying, the team found that the constriction formed a dog leg and the cave soon returned to its lengthy form with a 75m leg. However, as this was a diminishing inlet, the open sandy floor gave way to being more boulder strewn and was less like a bored tunnel. Small climbs became involved. The team passed a flowstone inlet on the left around 120m from the end and encountered a stooping passage feature. The cave opened out beyond but it was apparent that this main inlet was closing down. The passage narrowed predictably and the team came across a boulder choke. This was pushed for 15m unsurveyed until it completely choked.

The team took many photos on the way out; many of them show the fine tunnel shape of most of the cave. It was a cave of considerable beauty, although it is questionable and maybe unlikely whether this beauty would be apparent to non cavers expecting dramatic “showcave formations”.

After approximately 600m past the boulder choke, the cave split into 2 inlet streams, with the right hand stream being the major contributor of the flow. The left hand inlet continued for approximately 150m before becoming impassable. It continued in a diminished form of the main streamway and took the form of a rift rather than a tunnel passage at turns. The passage terminated soon after some impressive crystal walls, clean marble and some flowstone constricting the passage. A climb up and over some flowstone and boulders in the passage degenerated into a hands and knees crawl for approximately 60m at stream level; this diminished further and until it became a boulder choke with very little potential for further development. By this point the issuing stream was negligible. In a further effort, the surveyors found a breakdown chamber at a higher level, from the start of the stream level crawl. This also had little potential for further passage, especially in light of the main passage continuation 150m behind us.

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