Report 1999



12th March 1999

After yesterday’s success in Nguom Sap Mick, Howard, Steve and myself accompanied by Miss Nhu and a local guide, walked over a col to the village of Lung Sam, in search of the continuation of Nguom Sap.The area map clearly showed the Nguom Sap waterresurging and then sinking again in the Lung Sam doline.

Reaching the top of the col we could clearly see a massive cave entrance, with a large river rising to the left and sinking in the cave entrance.The pace quickened as we neared the entrance, it looked a dead cert.

The entrance was approximately 45 metres wide by 40 metres high, we descended a steep slope of breakdown to reach the river, which emerged from a sumped side and spewed forth across a large shingle floor.Excitedly, wedonned wetsuits and surveyed in.

After several hundred metres the stream shot off to the right in a 4 by 4 metre passage for 40 metres to a sump, the continuing main passage was high and slightly inclined.To the left were several ramps up to a massive high level fossil passage, which meandered around the continuing lower streamway for most of the cave.

The stream now did a sharp right turn, behind a large block at the start of the ’Master Plan.’Steve, our team fish, set off across a swim in a 5 metre wide by 20 metre high passage and we all followed like sheep. Later we discovered this section was just a wade.Beyond the swim, to the right a short passage discharged the main stream from a sump.Continuing downstream was easy walking on a shingle floor, the high level passage could be seen crossing some 15 metres above.We then came to an area of calcited breakdown, the passage above was massive but unreachable.The way on was a drop down between calcite flows to a low roofed swim called ‘the Canal.’

After 100 metres the canal again rejoined the upper fossil passage and dimensions of 12 metres by 30 metres followed, with fast flowing cascades and short swims.At a prominent corner we decided to call it a day and return to the high level passages near the entrance.


Climbing up the 40 metres slope we entered the 40 metre by 15 metre high ‘Roll with it’ passage.The floor was level, sandy and largely free of breakdown, so we wandered along doing 50 metre survey legs with silly grins.In the downstream direction we reached a pitch back down to stream level.However upstream the dimensions grew smaller until a large ramp down led back again to stream level near the entrance.

Back at the entrance, it was smiles all round.We’d surveyed 1.3km of superb passage and we just knew tomorrow’s return was not to be missed.

13th March 1999

Today’s plan was for Mick, Martin and myself to travel to yesterday’s last survey station.We were granted ½ hour of passage grabbing before marking a spot as the start of our surveying.

The second team of Howard, Fiona, Anette and Steve were to follow photographing and upon reaching yesterday’s last survey leg, they were to survey our ½ hour of grabbed passage.

Team Grab set off, quickly reaching yesterday’s last station.We then covered ½ hour of very sporting passages, with many cascades and short swims in passage generally 8 metres wide by 15 metres high.We started surveying in an area of fast flowing water, just before a 3 metre climb down.At the bottom the current swept us on, eventually the high level fossil passage dropped down and merged with the active level and the passage dimensions became a staggering 100 metres wide by 60 – 70 metres high.

The ‘Ha Lang Highway’ was truly awesome, the sort of passage we’d travelled to Vietnam to find.Huge stal columns adorned the passage, some fallen like massive tree trunks, and the stream was lost beneath the expanse of the boulder floor.As we surveyed another entrance came into view, possibly 400 metres away.We carried on past the steep ramp up to daylight, onto a second entrance where we surveyed out into the dense jungle of a doline.Stumbling round in the heat of the day clad in wetsuits was very unpleasant, with much relief we found a 3rd entrance back into the cave.It became obvious that the cave passage merely skirted the edge of the doline.We also noticed evidence of wood cutters, there must be a cut route overground to this point.

Underground the continuation was down some steep climbs to stream level, where the water deepened and we had to swim.After several hundred metres it become obvious that a sump was inevitable as the walls were dark and sombre.Leaving myself stranded on a rock island , Mick and Martin surveyed two more out of depth legs before calling it the end.Mick could be heard shouting “for f***s sake” as he repeatedly got caught up in the survey tape and the drag cord of his floating tackle sack, whilst trying to swim.


We returned to the ‘Ha Lang Highway’ for some food and then checked out some side passages before heading off out.We caught up with Howard’s team near the entrance, they’d completed their section of survey as well as taking a good photographic record of the first half of the cave.Unfortunately time restraints didn’t allow us a return.

Nguom Lung Sam was a stunning cave to explore. The surveying length was 2.7km and certainly for 3 members of the expedition, one of the best days exploration of the trip.The area map shows the Nguom Lung Sam River rising in a further doline, before sinking again and travelling under the Chinese border.The search for this continuation should be a must for the next expedition.

Peter O’Neil

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