I decided to make a writeup of the accident in Plura, to get a good picture for myself about the actual course of events
(Disclaimer: I'm not a cave diver, so take anything cave specific with a grain of salt. Also, note that all links are in their native language, so you'll have to run them through Google Translate yourself)
Summary of the Plura accident in February 2014
About the cave system
A short online article from the Geology Department at the University of Bergen, about the Plura cave system:
Pluragrotta ved Mo i Rana | Universitetet i Bergen
Translation of terms on the map image:
Plura nedløp - Where river Plura goes underground
Tørt elveleie - Dry river bed
Trollkjerka kollaps - Trollkjerka fall-in ("Trollkjerka" is the name of the place, lit. meaning "The troll church")
Sammenlenking på ~132m - Connection at ~132m
Steinugleflåget kollapspipe - Steinugleflåget fall-in pipe ("Steinugleflåget" is the name of the place, lit. meaning "The Stone owl cliff wall").
Footnote: A "flåg" is (AFAIK) an almost-but-not-quite-vertical cliff wall, a "stup" is a vertical cliff wall, a "skrent" is a small cliff wall, only a few meters high. The Norwegian language has at least as many words for rock, cliff and mountain formations as the Inuit language is claimed to have for snow...
Luftkammeret - The air chamber
<EDIT>
An English summary of the article from the University of Bergen
The Plura cave system is a limestone cave (karst cave) located in the eastern part of Rana municipality, Nordland county, Norway. The river Plura runs North from the lake Kalvatnet to the Rana river near the municipality center Mo. In the upper part of the Plura valley, the river runs underground for about 3.5km. Along the dry river bed we find two collapse structures: "Trollkjerka" and "Steinugleflåget". Both collapses go down at least to the groundwater level, and Prof. Lorentzen believes that the Steinugleflåget collapse structure reaches beneath the groundwater level down to the bottom of the cave system, i.e. about 230m beneath the surface.
The Plura cave system is claimed to be the world's deepest sump cave. From the spring of river Plura at Jordbru (where the Plura meetup is taking place), the first sump is rather shallow, not exceeding 30m depth and is the normal area for cave diving at Plura. After the first sump, there's a large air chamber before the cave plunges steeply down to ~130m before it comes up to the air chamber just South of the Steinugleflåget collapse pipe. From the surface, it's possible to ascend up into the Steinugleflåget cave, but the area is unstable and prone to rockslides. The caves at Steinugleflåget connect above the water level to Trollkjerka, where there are other cracks leading down to the water level. The river Plura runs underground a little more than 1.5km upstream from Trollkjerka. The underwater stream upstream of Trollkjerka has not been explored, as it's not possible to access it. However, the stream has been mapped using dyes, and this is used as a student excercise in one of the geology courses offered at the University.
</EDIT>
Plura is a very popular cave system to dive, and there has been an organized diving event there since 1997 [1] ("Pluratreffen" ("the Plura meetup"), later called "Uke 33" ("Week 33"), later named "Plurauka" ("the Plura week") [2]).
The connection between the Plura cave system and the Steinugleflåget cave was first found by Finnish cave divers (the "Divers of the dark" team, Sami Paakkarinen et al.) in October 2013. Report:
https://www.dropbox.com/s/6f50t92q7ujubhz/Diving Project Plurdalen 2013.pdf
News article about that expedition:
? Verdens dypeste sumpgrotte - Nordland
Preamble: The 2006 accident
During the meetup in 2006, Ståle Tveitane perished in the inner part of the Plura cave, while his buddy Bjarte Vestøl survived [1]. They had been 1300m into the cave, with a max depth of 110m [3], and the accident happened on the return leg of the dive, at approximately 75m depth [4]. It took the authorities almost two weeks to recover his body. The recovery operation was a cooperation project and included personell from the local police, the Norwegian Armed Forces, the Norwegian Civil Defense, Oslo fire and rescue brigade and a British deep diver team [3]. Oslo fire and rescue brigade was responsible for the organization of the operation. The British team was lead by Mark Dougherty, and the diving was performed by Rick Stanton and Jason Mallinson (last two names unconfirmed, my source is the Norwegian discussion forum). Ståle's body was recovered from the Plura side of the system, as the connection between the Plura cave system and the Steinugleflåget cave hadn't been found yet.
The 2006 body recovery (Summary of ref.# [4]):
The recovery operation took a total of 10 days, the first four were used for planning. Norwegian HES regulations do not allow the risk associated with dives like the ones needed to recover Ståle's body (even if some of the divers at Oslo fire and rescue brigade had experience in cave diving and had done penetration(?) dives to recover bodies from the Rocknes wreck in 2001), so a British team was asked to provide the deep diving for recovery of the body. Oslo fire and rescue brigade provided support divers for the operation. There was some discussion with private cave divers from Norway as to who should perform the recovery dives, but the authorities decided on the British team. Diving was commenced on day 6. On day 7, communication was established between the air chamber and the surface, the dead body was located at 63m depth and the deceased's UW scooter was taken out. On day 8, Ståle's body was moved from 63m depth to 11m depth in the inner sump by the British team, and the Norwegian support divers brought the body up to the air chamber while the British team rested. After this, Norwegian and British divers cooperated to bring the body to the other end of the air chamber, and the Norwegian team brought Ståle's body to the surface. Day 9 was used for removing the equipment from the site, and day 10 was used for evaluation of the operation. [4]
Before the 2006 accident, there had been no official body representing Norwegian cave divers. Seeing the need for an official organization, The Norwegian Cave Diving Society was founded in the aftermath of Ståle's death [1].
The second accident
On the morning of Feb 7th, Norwegian media reported that two divers had died in the Plura cave system, while three had received pressure chamber treatment at Tromsø University Hospital. Only one of the three showed clinical symptoms of DCS [5,6,7]. The diver showing symptoms of DCS received two chamber treatments, while the other two, who had cut short their deco time but didn't show clinical symptoms of DCS, received one treatment [no ref, based on what I read at the time and can't find again. It may have been an error in the news which has now been corrected]. Based on the fuzzily reported facts, I assume that the treatment was according to US Navy Table 6, which is the standard decompression chamber treatment given in Norway as well. Initial reports indicated that the deceased divers were located at 130m depth [8], however this turned later out not to be the case [9,12]. The accident happened after the deepest part of the sump, at approximately 110m. Planning of the body recovery operation was started quickly, and the operation was to a large extent based on the recovery of Ståle Tveitane's body in 2006 [10,11]. The names of the deceased were released to media four days after the accident [12], and about the same time the Finnish Diving Society published a short report from the three survivors about what happened during the fatal dive [13,14]. The actual course of events under water is well described in the Finnish accident report:
<EDIT2>
The planned dive was a penetration dive from Plura, through the connection found by the "Divers of the dark" team in 2013, to Steinugleflåget. The five divers dived in two teams. The first team (Diver 1 and Diver 2) entered the water first, the second team (Divers 3, 4 and 5) entered the water about two hours later. After traversing the deepest part of the sump at ~130m, Diver 2 gets stuck in a restriction at about 110m, has problems with his rebreather and dies. Diver 1 continues to the exit at Steinugleflåget to wait there for the other divers. When the second team arrives at the restriction at 110m, Diver 3 tries to free the dead body of Diver 2, but fails. He is able to doff his gear and get through the restriction. Diver 4 experiences problems with his rebreather and switches to his bailout gas, but dies as well. Diver 3 continues to Steinugleflåget, while Diver 5 has to return to Plura. All three surviving divers face an increased decompression obligation after the accident and have to cut their decompression time shorter than required, but only Diver 3 shows clinical symptoms of DCS (joint pain). Divers 1 and 3 manage to alert the authorities by the help of a local resident, and all three divers are airlifted to Tromsø University Hospital for medical treatment. [14]
</EDIT2>
Media started speculating about whether the cave would be closed for diving [15], but a permanent ban cannot be enforced without passing a specific law, as it conflicts with the lawful right to roam in Norway [16]. Such laws have, however, been passed before, regarding BASE jumping in Trollveggen in Western Norway, for the safety of the rescue personell.
The failed body recovery operation
On Feb 20, the British diving team arrived in Rana, lead by Mark Dougherty who also was the dive leader for the recovery of Ståle Tveitane's body in 2006 [17]. On the Norwegian discussion forum there is an unconfirmed claim that the divers were Rick Stanton and Jason Mallinson (who participated in the operation in 2006) and Jonathan Volanthen. As in 2006, the operation was coordinated by Oslo fire and rescue brigade, with local police participating. Oslo fire and rescue brigade also provided support divers, like in 2006. This time, the operation started at the Steinugleflåget cave [18,19,20], probably to avoid passing the deepest part of the sump twice and maybe to avoid having to traverse the first sump from Plura into the air chamber, then across the air chamber before starting the recovery dives. The diving part of the operation was scheduled to take eight days [21]. The first dive of the recovery operation was on Feb 21st [22]. On Feb 25th, there was a press conference where the decision to abort the recovery operation and that it was considered too dangerous for the recovery divers was published [23,24]. The divers were not able to free Diver 2's body, and they considered it far too dangerous to pass through the restriction to access Diver 4's body while Diver 2's body was still partly blocking the restriction. It's of course possible to discuss the decision to recover the bodies from the Steinugleflåget side of the restriction where Diver 2 got stuck and died, with Diver 4 dying on the Plura side of the restriction. However, it seems that either way, the recovery divers would have to pass restrictions on their way to and from the dead Finnish divers, and by starting from the Plura side the recovery divers would face the added complications of the deepest part of the sump at 130m and the air chamber between the outer and the inner parts of the Plura system. The discussion about a permanent closure of the Plura cave system to diving is ongoing at the time of writing [24], but the temporary ban on traffic and diving in the area is upheld until further notice [25,26]. However, the Norwegian Cave Diving Society says that they will not support a permanent ban [26], and the annual meetup at Plura ("Plurauka") is still planned as normal [27].
A video interview (in English) of Mark Dougherty at his arrival in Rana can be seen in ref. [17], and the full press conference about the decision to abort the recovery operation can be seen in ref. [23]. In the press conference, Mark Dougherty gives his statement in English at the beginning, and answers question in English at the end. The rest of the press conference is in Norwegian.
References
[1]
Troglodytt Page 15.
[2]
Plurauka
[3]
? Jeg skulle gjerne vært med og hentet Ståle ut | Rana Blad
[4]
Grottedykkerulykken i Pluras underjordiske løp
[5]
To dykkere omkom i vannfylt grotte - Nordland
[6]
Slik ble dykkerne behandlet - Troms og Finnmark
[7]
To døde i dykkerulykke | Rana Blad
[8]
? Befinner seg på 130 meters dyp - Nordland
[9]
Får ikke hentet opp dykkerne fra Pluragrotten - VG Nett
[10]
? Det kan nesten ikke bli verre - Nordland
[11]
Dykkerlege:?Dette er ekstremdykking - Nordland
[12]
Dette gikk galt i Pluragrotta - Nordland
[13]
Sukeltajaliitto ry - Näytä uutinen
[14]
https://docs.google.com/file/d/0B-iDm0Pmt3MYU3hxb0tZS3llTGpWVnZ0RWlPeDY5NTJybFVF/view?pli=1&sle=true
[15]
Vurderer dykkerforbud i dødsgrotta - Nordland
[16]
http://www.miljodirektoratet.no/Documents/publikasjoner/M86/M86.pdf
[17]
Krevende operasjon i Pluragrotta - Nordland
[18]
Komplisert og krevende | BA
[19]
Må frakte 400 kilo utstyr ned i grotta | AN
[20]
Krevende operasjon i Pluragrotta - Nordland
[21]
Krevende jobb for spesialdykkerne | Rana Blad
[22]
Har vært nede i dypet | Rana Blad
[23]
Henter ikke opp de omkomne - Nordland
[24]
Ber politiet holde dødsgrotta åpen - Nordland
[25]
Midlertidig ferdselsforbud | Rana Blad
[26]
Grottedykkerne støtter dykkerforbud - Nordland
[27]
Avlyser ikke dykkertreff - Nordland
