Incident Report

2019-04-16Three days before the incident, the three divers had a recce dive at Mill Pond. The cave had already been pushed for 100m from surface, mostly in low muddy passage, to a large airbell, where the way on was lost. Vis was around 2m for the first diver, but quickly deteriorated to zero for the return journey and for the subsequent divers. The cave had been pushed on 1mm tech line, so the divers decided that to continue they would replace the line with 4mm polyprop in order to make it safer. Three days later the three divers arrived on site with some surface support. It was agreed that the first diver would lay the new line alongside the old line, then after some time the second diver would remove the old line. The pair would then meet in the airball and resume exploration. The first diver entered the cave and just before entering the low bedding plane at the start of the cave, looked back to see the second diver had not waited. The first diver decided to continue, but subsequently got stuck in the far right hand side of the passage and lost reference to the old line (but still had the new line reel in hand). After extracting himself from the restriction, the first diver started laying line along the bedding in rapidly deteriorating visibility (around 40cm), still not finding the old line - which was odd. Once through the bedding, the first diver spotted two distinct rocks which the old line was belayed to, but no old line. Continuing on, the visibility deteriorated to zero and the first diver felt he was in a low bedding, which was odd as the cave beyond the initial bedding was somewhat larger. Therefore the first diver locked off the reel, dumped it in the mud and headed home - fully expecting to see the second diver on the surface. Once out, there was no second diver - on the return dive the first diver did not detect another diver in the sump at any point. The first diver immediately headed back into the cave, but once past the distinctive 2 rocks, the visibility was again zero, the the diver decided to head back to base and come up with a better plan. The third diver then kitted up and entered the cave around 30 minutes later, he eventually got to the first divers line reel, didn’t recognise the passage, so returned to the surface, having concluded that the first diver had gone the wrong way. It was then decided that the first diver would enter the water 2 hours later, in order to give the visibility a chance to clear. During this time, the visibility in the water coming out of the cave cleared, then went murky again - which we assumed was the second diver trying to find the way out. This gave us confidence that he had made it to the airball 100m in and was at least for now, alive. At 8pm the first diver then entered the cave for a third time and tried to find the way on, laying line up and right from the two distinct rocks. The diver simply round the roof of the cave passage and could not find the way on. Due to poor visibly and now lack of gas (this was the 3rd dive on a set of 80s), the first diver headed for home. The third diver then entered the water to try and find the way on, he returned 15 minutes later having not got through the initial bedding plane, having got stuck. At this point it was decided that as we now didn’t have much remaining gas and were both exhausted and were starting to make mistakes, that we would resume the first first thing in the morning with fresh bottles. As the cave was 18 degrees, it was thought that the diver was either safe and well in the airball, or already dead - therefore there was no immediate time pressure. The first diver asked one of the surface support to remain at the cave entrance over night in.case the second diver got himself out and asked two other people to come over from our accommodation from the wider group. When the first and third divers returned to the accommodation, the third diver phoned John Volanthen for advice. The first diver spoke to him at length explaining the situation. JV advised that the third diver should probably not re-enter the water, but that the first diver should return straight away and lay splays of line from the end of the line in order for the second diver to find. The first diver had no gas (as bottles had been taken away for filling) and was exhausted. He also wasn’t convinced that this was the correct course of action as he was convinced he was in the wrong place. Therefore JV advised that cave rescue be called. At this point the first diver still expected the head back into the cave first thing in the morning. Over night, some of the other cavers on the trip phoned cave rescue, while the first and third divers slept. Edd Sorenson and Mike Young were contacted and agreed to come over in order to continue the search. At 6am the first diver got up and started preparing his equipment. He was then informed of the plan and told he probably didn’t need to dive. He still headed over to the cave in order to brief cave rescue as well as Edd and Mike. At 6pm that afternoon, Edd entered the cave and 45 minutes returned with the second diver, alive and well. Four days later, the first diver returned to the cave, to give the land owner a bottle of whiskey and to re-enter the cave to tidy up the lines and retrieve left equipment. The first diver found Edds line attached to the end of his line beyond the two rocks. The new line was in a higher, larger part of the passage and after around 20m was then tied to a reel containing the old line. After tiding up and retreating equipment the diver headed for the surface and got a beer. The first diver is convinced that the second diver passed him while he was stuck in the bedding plane. This would account for the fact that the first diver never found the old line and had very bad visibility on the way in. It is thought that the second diver reeled in around 70m of the old line, before tying the reel off. The report from the second diver is somewhat different, but the first diver is convinced this is what happened.The lessoned learned from this incident are far and wide and are probably too complex for this report. However the first diver is convinced that if the second diver had not continued to reel in the old line after loosing the new line, then he would have found it and all would have been well. Therefore the main lesson is to always keep a continuous line to the surface! I think the main lessons learnt are to not be such a hurry to push on to exploration - a more slow and calculated approach would have meant that this would have never happened. The old line should have definitely been removed on the way out. Having said that, the poor dive plan should have simply meant a failed dive and a return later, and not somebody being stuck for 26 hours, Finally, if multiple people are in a sump at the same time, espesally when somewhat acting as a team, then a proper dive brief should have been carried out. If the first and second diver were on the same page before the dive, then this incident would have never had happened.