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San Agustin 2013: Sistema Huautla established as the deepest cave in the Western Hemisphere

Trip ReportJames HipkissComment

Sistema Huautla established as the deepest cave in the Western Hemisphere after a 7 week long caving and diving expedition featuringmore than 40 cave explorers.

Short summary of the expedition: Caving began on Tuesday 26th February. Thanks to a strong team within one week the cave was rigged to sump 1, camp 3 established and Jason Mallinson had relined sump 1 and 2. After another week the rest of the diving, exploration, beyond sump supplies and the four dry tubes were ready at the sump so that a team of 5 divers could spend one week exploring. Jason went through and set up camp 6 on Monday 11th March. The following day the rest of the divers made their way through sump 1 and 2. In total 6 dry tubes worth of gear was dived through with each of the three rebreather divers making two dives. A total of 6 dives were made in sump 9 between Jason Mallinson and Chris Jewell. On the first dive Jason reached -30m in poor visibility. On the next dive Chris reached -48m before ascending to surface in a static pool after 250m. A muddy ascending tube was followed for around 30m.

On the third dive Jason returned to this section with some rope but all passages closed down. Next Chris and Jason dived together with each diver on opposite sides of the passage in an attempt to find the main underwater continuation. Jason found a tunnel leading off the left hand wall which both divers followed down to -60m before surveying out. The final dive was made by Jason who followed this tunnel down to -81m which was the limit of the trimix being used. The final dive reached a point 440m into sump 9. Meanwhile the rest of the team (Mirek Kopertowski, Jon Lillestolen and Rich Hudson) were busy looking for dry passages. The Rio Iglesia waterfall was found to choke after a short distance and short sections of cave were surveyed in Perseverance hall and shortly before the low airspace swim. However long extensions were discovered leading from the back of the sump 9 chamber. These extensions followed the trend of Adams Avenue and in places dropped back down into known cave. In total 1,774m of dry passages were surveyed but no bypass to sump 9 discovered.

One mystery does remain however, when on the last day an undescended pitch was reached. Appearances suggested this would drop into known cave and the team was short of time and rigging gear so it was left. However when we plotted the survey data this pitch was going into new territory. Whilst the diving team was beyond the sumps they were in touch with the rest of the cavers at camp 3 by Nicola radio and teams took it in turns to stay at camp 3 and monitor the radio twice a day. During this period the route up to Anthrodite hall was. On Monday 18th March the diving team returned to camp 3 and a day was spent hauling kit from the sump before most people headed to the surface for some rest. During the following week (week 4) most of the diving kit was carried out of the cave and at the same time photos and videos taken.

Week 5 saw the arrival of our de-rig team and whilst they were getting ready to camp the rest of the diving kit came out. One final camping trip saw the cave de-rigged to the 620 depot. After that several long day trips during week 6 de-rigged the cave completely. In total we estimate that something like 30bags of diving/exploration kit (average weight of 16kg per bag) were carried in and out of the cave.

Thanks to a strong support team of more than 30 cavers from the UK, Canada, US and Mexico all this was accomplished quickly and efficiently. Thanks to our sponsors for making this happen and thanks to the local people who have made us feel very welcome.

More info - www.facebook.com/CaveDive andwww.cdg-exped.org