The expedition “Boisun Tau 2011”, on the border between Uzbekistan and Tajikistan, took place from 1 to 20 August 2011, and was organised by the Association of Urals Speleologists. The participants were 19 Russian speleologists and 3 Italian speleologists: two members of La Venta and one member of the Gruppo Speleologico Padovano (Padua Speleological Group). Organisation of logistics, scientific research and exploration was handled entirely by the Russians. La Venta and GSP provided part of the technical equipment, as well as taking care of the photographic and video documentation.
The main objective of the expedition was to film the exploration of other caves in the Hodja Gur Gur Ata wall, and to continue the work previously begun in Festivalnaja.
The equipment was transported to the first camp at 2500 m on mules, and from there on, we carried it ourselves. The lack of water significantly conditioned the upward progress of the camps (2500, 3000, 3300 m to camp Oasis).
The idea was to pitch the last camp above the wall, but the total lack of water up there excluded that possibility. So above the wall we just set up a temporary camp with three people, whose task it was, in three days' work, to reach the Dark Star cave from above and from there to equip a descent route passing by the entrance, and continuing to the base of the wall (some 450 metres' vertical drop).
Fortunately at that point at the base of the wall there was a small spring, already recorded by the 1989 British expedition. Thus it was possible to move the camp from the Oasis to the base of Dark Star, approximately 4.5 km as the crow flies. With this set-up we could almost certainly also have reached Ulugh Begh, the legendary cave with the highest entrance in the world (3800 m) but we didn't have enough time.
In terms of materials, the Russians were well equipped, although their Ukrainian ropes were rather too stiff. The use of small drills supplied by us (Uneo) and recharged each morning using two solar panels was a great success. The panels were also useful for recharging cameras, computers and satellite phones as well as batteries for personal use. The system worked perfectly, especially since there is no lack of sunshine up there.
In terms of exploring the area, some significantly important objectives were reached. The very dry summer made it possible to explore a completely icy Dark Star, without the problems faced by the British explorers in 1991, who were stopped in their tracks by deep lakes. The Frozen Beck stream has clearly changed since then, so much that the descriptions given by the British team sometimes did not correspond with the current reality.
We quickly reached the limit of the British exploration, after two kilometres of splendid tunnels. We descended a 25-metre shaft and climbed back up some ten metres to find the fossil gallery, but we realised we had entered a cave already explored by another Russian group back in 1988: entrance R21.
The main branch of Dark Star actually runs almost parallel to the wall, and cuts across a promontory; hence, considering the strong draught, it was to be expected that we were heading towards an entrance lower in the wall. The last stretch of cave (about 100 metres) is completely covered in ice crystals, with winds blasting through at temperatures of -1.5/-2° C.
In the subsequent excursions we explored a large meander that climbs decisively south, the Passakaloski branch. Here, after a series of climbs, it was no surprise when the all-Italian excursion came upon another spectacular entrance in the wall, named Red Wine, higher than the other five known ones, at an altitude of around 3650 metres, maybe more. But the most interesting discovery was made during the final days, while climbing the wall of the British shaft, when a large tunnel was discovered perpendicular to the main one, which soon leads into a spectacular ice portal in a large space, the Full Moon Hall. This is in fact a huge tunnel that climbs upwards (White Wine, with exploration limit at the base of a slope) and downwards (over a kilometre, ending with a siphon 300 metres below the upper entrance).
Before the siphon, a series of fossil galleries were identified, not surveyed, but explored for several hundred metres, and constantly large and spacious. This is where our explorations stopped, as we had run out of time. There is certainly much still to do, and great potential. Together with our Russian friends, we decided to call this cave complex the Central Hodja Gur Gur Ata Karstic System (Dark Star, Red Wine, Capricorn One, Cancro, Passakaloski, R21), with almost five kilometres surveyed and over 300 metres of total height difference. In addition to the explorations in this area, two Russian groups (4+4) continued the work at Festivalnaja. One group once again reached the bottom of the cave (-620) equipping it for ropes and getting rid of the steel cables. They noted that the bottom is insurmountable, but just a little before that, some ascents would be possible. The second group worked in a new area of fossil galleries above the Bolscjioi Grot, discovered last year. Several hundred metres of passageways were explored, some of which were quite uncomfortable. There is still much to do and to map. The Dark Star group also saw to repositioning many entrances using GPS.