Yunnan Resurgences 2004 Expedition Expedition report
Timing of expedition
The expedition was held in late January during the winter dry season. The weather in the Jin Sha Jiang valley was surprisingly temperate, although there was snow cover above 3000m. Water flow in Shui Lian Dong was one-tenth of that measured in the summer and C3-45 resurgence was free of silt noted in the summer, making it a good time for upstream exploration and potentially for future diving expeditions.
The expedition coincided with the two-week Chinese New Year holiday. This had a number of effects on the expedition. Hotels, buses, and trains were generally more expensive and busier than usual. New Year's day was January 22nd, and before the 20th train and bus tickets were difficult to buy. On the 20th trains were relatively uncrowded. On the 21st - 23rd many local and long-distance buses were cancelled. In the balance it may be best to avoid the holiday in the future, or at least plan to be in the research area well in advance of its start.
The expedition used two specially made, extra strong, 120 cm tall, 40cm wide, 60cm deep luggage trollies. They greatly facilitated moving equipment between trains and buses. With the trollies, two members of the expedition were able to move over 145 kg of equipment from Guilin to Kunming by train without porters. The small trollies were found to be vastly superior to a larger version previously employed by Hong Meigui.
The electricity at Shui Lian Dong was normally 170V, occasionally dropping to 0 or increasing to 220V. No problems were noted with battery chargers, but the expedition's printer (Canon BJ-30) would not work below 220V. A voltage regulator may be useful for future work in this area.
Survey instruments at altitude
The expedition employed precision sighting compasses (Suunto KB-14/360, Silva Model 80) and clinometers (Suunto PM5, Silva Clinomaster) which are widely used for cave surveying in Britain. On their eighth day above 1900m ASL two of the four instruments (the Suunto KB-14/360 and Silva Clinomaster) which had previously been normal developed large bubbles. The day before the bubbles developed the Silva instruments were taken on a walk which reached 2900m ASL. The bubbles persisted throughout the remainder of the expedition. The instruments returned to normal when taken back to 200 m ASL where they are stored between expeditions
Bubbles in survey instruments are a problem for high altitude caving expeditions. They make it impossible to take high-angle clinometer readings, and may decrease accuracy of readings with both compasses and clinometers. Future expeditions will need to develop methods of dealing with them.