Lushan 2003 Expedition Expedition report
This report was prepared for the Long Men Dong Development Co.
Longmen Dong is primarily formed in conglomerate rock and is now the longest known, mapped and explored conglomerate cave in China. There are two known penetrable entrances to the cave, the larger being the current showcave entrance, the second located roughly one kilometre to the southwest. The surveyed cave falls within a rectangle measuring 1.33 km east to west and 1.76 km north to south and has a surveyed length of 13.2km, a high density of cave development, also indicated by the presence of 24 loops in the completed survey. The vertical range of the cave is 356m and this can be traversed entirely without resort to ropes or ladder work. The cave varies in character throughout and exhibits many distinct forms of cave passage. The potential for the discovery of additional passage is extremely high and the length of the mapped cave is bounded only by available time. A strong wind was observed at the entrance and at many other locations inside the cave which hint at further entrances yet to be discovered.
In the course of the expedition we made over 3600 scientific measurements and collected 238 pages of notes and drawings. These measurements enabled us to make a highly accurate three dimensional model of the route through the cave. The error of this model is typically less than 1%. The accompanying drawings, notes and additional measurements made underground allow us to create accurate maps of the cave.
3. Underground passages
Longmen Dong has a surveyed length of 13.2km and depth of 356m. . As of June 2003, Longmen Dong ranked No. 13 on the list of deep caves surveyed in China, and No. 7 on the list of long caves surveyed in China. 2.1km of passage in Longmen Dong has been developed for tourism with lights and concrete paths. The largest passage in Longmen Dong is 28m wide and 15m tall.
There are many loops in Longmen Dong. The path of the longest surveyed loop is 2926m long. The route from the showcave entrance to the farthest point surveyed is 2865m long.
Longmen Dong has two main entrances: the showcave entrance and Taozi Gou. The horizontal distance between the entrances is 931m on a bearing of 61 degrees. The path through the cave between the two entrances is 1922 m long. The showcave entrance is at 1016 m above sea level. Taozi Gou entrance is 106 m lower at an elevation of 910 m.
3. Underground water
Longmen Dong has a complicated system of underground streams. More than 37 inlets were recorded in Longmen Dong. Four major streamways were observed, originating from the north, northwest, west, and east. In total 4338m of stream passage were surveyed. The longest streamway is 2860m long, running 1362m horizontally and 355m vertically from the northwest to Difeng Sump. Difeng Sump is the largest lake in the cave, with a surface area of 250m2. Longmen Dong has many waterfalls. Over 60 waterfalls were mapped, 16 of which are over 2m tall.
4. Air flow
Strong wind has been noted in over 50 places in Longmen Dong. In general the wind blows from north to south in the cave. Wind blows out of the main showcave and Taozi Gou entrances south, indicating there are most likely other entrances to the cave in the north.
Many animals live in Longmen Dong. During the course of mapping, bats, rats, millipedes, shrimp, and leeches were observed.
The cave is of notable speleological interest by virtue of its changeable character, its potential for further exploration and its development in conglomerate rock. The cave is of geologically young development but still has some areas of speleothem development which in places can be quite beautiful. The main streamway is developed as a series of small waterfalls and cascades which add both sporting value and beauty. The number of possible loops and relatively easy passages make it a good system for the introduction of the sport to new cavers.