22 October 2005

Accident at Dersios - 25 September 2005

The text which follows has appeared in the forum of Selas Caving Club with comments and also with some editing, in the e-Magazine "Speleonews" which is published by members of the Greek Caving Community on a monthly basis.

The sink-hole Dersios is located on the Palaiochora plateau at a height of 755m and belongs within the boundary of the municipality of Tyros or Tyrosapounakeika of the Arcadia Prefecture. The distance from Tyros is about 45 minutes on a dirt track.

The sinkhole was first explored by a French team in August 1974 with the participation of ESE - the Hellenic Speleological Society. Since 2001, SELAS Caving club, Greece has been conducting expeditions to Dersios, emptying the first sump in 2003 (doubling the depth and more than tripling the length of the cave). This year expeditions were carried out almost every week from June to the end of September (August excluded). This years perseverant attempts to empty other sumps higher in the cave have allowed the SELAS caving club's teams to explore new undiscovered sections of a length of 570m. I hope that after the Panhellenic Speleological Meeting we'll have a chance to present the cave in detail.

On the weekend of 24-25 September three of us had come up from Athens - myself, with Nikos Mitsakis and Komninos Boutaras. Theodossis Kourbelis, a local caver and member of the club also took part in the expedition.

Komninos returned to Athens on the evening of Saturday and we gave him the phone numbers of our other halves so he could call them to let them know we would be out late and they should not worry. We had got used to the luxury of leaving the plateau in daylight recently, but the tasks to be done on this trip would delay us.

In the morning while getting ready to go into the cave, we told Theodossis to call Niki in Athens in the event that we did not call him first before 1am on Monday morning. We figured that we would have finished and would have made it out much sooner. Nikos and I entered a little after one pm on Sunday and began the tasks assigned to each of us - survey / sketch-map and then de-rigging from the bottom (-161m) to the exit.

Cause of the incident
In the area called the "screw" a few meters from the rope leading up to it, there is a small ascent of 2-3 meters on boulders which requires a little clambering. There, probably on account of my familiarity with the area (I had been through there about 15 times this year alone), two errors happened at the same time which led me to the bed of convalescence.

First: I did not have the weight of my body on three different points, as common sense demands, and
Second: I had not checked the steadiness of the rock onto which I transferred all my weight, something which resulted in the rock moving from its place…

If only one of the two had happened, you would not be reading this text right now - because these two things happened in conjunction, we had the inevitable result:

What happened
I fell backwards and to the side from a height of about 2m. I hit the side wall with my back (well, the sack took the hit) and helmet. From there I slid and fell a little more (the side wall was sloped and I ended up on my back with my helmet again hitting the floor of the cave. The vertical fall was finished. I drew in some breath and was happy to still be alive.

Well, my bad luck did not end there - my left foot had come to rest in between two rocks or stones or something and was firmly stuck. And the bad luck continued: my body was still moving - probably on account of some of the vertical kinetic energy wanting to keep me moving after reaching my lowest possible point. Well, with the foot firmly wedged and the rest of the leg wanting to move, there was some unnatural movement within the ankle. I immediately felt a warmth spreading internally on the external part of the ankle. And I recall this making a strange impression on me as I had felt the pain on the internal side of my ankle. At about this point and probably a little before I let out a cry of pain, Nikos was at the head of the preceding pitch, just in time to see me taking up my post-fall position.

Immediate reactions
"I'm OK, my ankle hurts" I say to him. He left me to calm myself a little and check over my other limbs. He asked if I could step on the ankle and I told him that I reckoned I probably could. He told me we would have to move from the place where we were because if it rained (not at all impossible, given the thunderstorms all weekend) where we were currently sitting would not be the best of places to be waiting. I was happy and took courage from the fact that the cave rescue check-list had kicked in and was being gone through but more so because I was with someone like Nikos - joint head of the Hellenic Caving Federation's Cave Rescue Team. And so, when we saw that I was not in too much pain we started the process of getting me out of the dangerous part of the cave - as Nikos had said, "you have to move it now while the foot is still warm". He announced the time of the accident and we started for the entrance. It was half past eight.

Encumbered egression…
Ah, yes, but… I could not put any weight on the bastard. So, with one foot, with my hands and with the left knee, I began my ascent to the flatter part of the "screw". The right shin had taken a knock but I made it in the end with a lot of pulling from Nikos and a little pain every now and then when I'd bump into rocks or other impediments. Nikos explained that we should not stay there and we should absolutely get as far as the traverse over the little lake. Later he explained that it would have really challenged the rescue team to get a stretcher through that section. Nikos ascended the pitch with the dried well at the bottom which leads to the chamber with the lake and the stalactite. I followed him up. He tied a rope to my center mallion and heaved me up with his hand ascender. Leaning my weight a little against the walls and a little on Nikos I got to the pitch head in the chamber with the stalagmite. He went up the next pitch and rigged a second rope which he descended and came to sit next to me to help me out. When we got to the traverse line above the little lake, he again tied a rope to my central mallion and pulled me over the traverse like a dog on a lead.

Should I stay or should I go now?
Now we were there, we had another look at the strategy to be followed. We were now beyond the dangerous section which may have flooded in the event of rain and also through the narrows which would have caused the rescue team trouble. "So," he says, "we either get out of the cave on our own - which is the best course of action, however long it takes us to get out, or we set up an emergency shelter and wait - in which case we'll be out tomorrow night."

I was very enthusiastic with our progress so far - we had managed for Nikos to lift me about 20m vertically and about 40m of the way to the entrance horizontally from the site of the accident. I knew we had started at station 21 on the survey and we were now at station 13 - hey, I'd been surveying and sketch-mapping all weekend, I knew exactly where we were… We had about 146m of horizontal travel left, and about 50m of vertical travel.

We still had a way to go, but we both preferred to get out of there without waiting for the rescue, however much this would knacker us so that we could get out far enough and quickly enough to forestall Theodossis call to Niki and her call to the Cave Rescue. The route ahead was uneven - especially uneven for a guy on all fours - and there were still four on-rope ascents before the double ascent at the entrance.

We made our decision. We set off.

Heading for the lake
I was crawling on all fours, holding on to Nikos for support dragging myself over boulders and other obstacles and at the pitches Nikos would draw me up slowly with his ascender on a rope tied to my central mallion: in this way we made our way slowly to the entrance.

At the entrance to the second side-branch, we found the sacks with the diving equipment. Nikos was already carrying the rigging he had de-rigged, his own personal equipment, my personal equipment, the victim and now, to this he added the bottles…

He let me walk and crawl ahead at my own pace, while he took all the sacks to the lake at the entrance. I was now so exhausted that every few meters I would have to sit and rest for an period of time equal in minutes for the meters covered.

Lakeside counterweight
At the lake Nikos prepared the counterweight to raise me. There was no pulley. Usually Nikos carries on all the time, but all his personal gear was in Russia (where it had been since July when he had gone for Krubera-Voronya) and the pulley was with it. For this reason he set up the counterweight with a karabiner - with all the great losses to friction this implies: the losses were so great that despite our difference in weight we had a tough time raising me, despite my pulling myself up with an ascender on a different line. For the final pitch, he hung the bottles underneath him as well for the extra weight, and finally I was outside again.

I dragged myself along a little and then the equally knackered Nikos helped me to the road where I waited for him to come from the cheesevault - fortunately we had gathered up our things a little and tidied up in the morning before entering the cave. We were out at half past midnight. It is normally a twenty minute route for me - we had done it in four hours, but we had done it.

Next steps
Especially pleased with our performance we set off for Tyros to try and get within the range of a cell phone antenna and call off the alarm. Theodossis had called Niki at one am on the dot. She, in her turn had thought it prudent to wait a little (thankfully) before calling out the cave rescue team. She had been a little influenced by Komninos' call and knowing what the cave was like, decided to give us some extra time to check in.

We went (via Argos for gyros, of course) to Evangelismos Hospital which was on call that night. It did not seem too strange to them that the trauma happened at 2030hrs and was brought to their attention at 0530hrs the next morning. They didn't seem too perturbed by the mud caking my hands and arms. They did not like the fact I had been sort of putting a little weight on the foot now and then for four hours - but what to do? They x-rayed it, shoved it in a plaster cast (despite the manic muscle-cramps I had while they were trying) and I left with a diagnosis of "second degree sprain".

Today that I am writing, it is Thursday. I have not yet stepped any weight onto it, but it has stopped hurting continuously. From what it seems, it will take a while to drive and a little longer to enter another cave...

[Now that I am translating, it is four weeks exactly since the accident - I am still largely bedridden but on the mend - going to physiotherapy, which seems to be helping the swelling. No idea whether next week I'll be at the 8th Panhellenic Speleological Meeting with or without my crutches...]

* It's not a bad idea to never underestimate the dangers in an underground space - however familiar that space may be.
* I ought to improve my clambering skills a little...
* If there had been three rather than two of us, we would have finished far sooner.
* Pulleys are indeed useful.
* Knowledge and practice in rescue techniques / counterweight techniques, etc are really rather useful and should be held by at least one member of the expedition (if it had not been for Nikos or someone with similar knowledge and skills, I would not have come out quite so easily).
* The fact that we decided to try to exit under our own steam rather than wait for the cave rescue team worked to our advantage as it felt positive to actually be doing something.

Excerpt from the survey

The red cross marks the point where the accident happened. Clicking on the image will open a larger version.

Dersios in Descent Magazine

Descent 186 Cover The first pitch at Dersios is featured on the cover of the current Descent Magazine. The photo was taken by Robbie Shone who won the photography competition at the 14th International Caving Congress held in Athens this summer. Robbie had the opportunity to visit Dersios along with about ten other congress participants during one of the pre-and post congress excursions organised by Selas caving club. The excursion visited a number of caves of mount Parnon, including the famous Propantes pothole.

Issue 186: "Descending Dersios during the International Congress in Greece - Photograph by Robbie Shone"

A visit to Dersios 24-25 September 2005

A visit to Dersios 24-25 September 2005

The sink-hole Dersios is located on the Palaiochora plateau at a height of 755m and belongs within the boundary of the municipality of Tyros or Tyrosapounakeika of the Arcadia Prefecture. The distance from Tyros is about 45 minutes on a dirt track.

The sinkhole was first explored by a French team in August 1974 with the participation of ESE - the Hellenic Speleological Society. Since 2001, SELAS Caving club, Greece has been conducting expeditions to Dersios, emptying the first sump in 2003 (doubling the depth and more than tripling the length of the cave). This year expeditions were carried out almost every week from June to the end of September (August excluded). This years perseverant attempts to empty other sumps higher in the cave have allowed the SELAS caving club's teams to explore new undiscovered sections of a length of ~570m.

We got to the cheesevault late on Friday night with Nikos driving and found Komninos already there. Komninos had gathered wood and set a fire in the fireplace. We exchanged stories of lightning strikes and fog during the trip there and prepared for bed.

In the morning the usual orgy of eating took place and we then got the divers' bottles ready for the dive and set off for the entrance.

The divers would go to de-rig the new section and survey the last part of it (in the end, it was 14 stations ~100m), while I went to make the sketch map in the old section and alter the hosepipe position in the first sump ready for winter. All tasks of the day were conducted successfully and Komninos came out to cook and prepare for the return while I stayed behind with Nikos for the sketch map.

After the successful omelet of 10 September we went mad this weekend: two different types of sausage, fried chicken wings (chicken spareparts according to Theodossis), omelets, roasted chestnuts and onions in the ashes. Boy did we eat that weekend!

The second day tasks were Nikos to survey the sump in the first sidebranch. There's a 50m or so continuation a little lower than the route taken in exploration in July. Because it was narrow and kept getting silty, he only managed a few measurements. I carried on the sketch map and at some point in the afternoon Nikos started the de-rigging and we went on together to the exit. I have written elsewhere about the method of our exit.

In addition to survey measurements and the sketch map a rigging chart was drafted as was a list of all foreign objects found inside the sinkhole to try and get a chronological outline of the deposition of items in the cave - and therefore an idea of to what extent the cave gets blocked with water. It needs a little bit of chasing but there may be something useful at the end of it. According to Theodossis, the last time it blocked right up was in 1991. This means that the items found with a more recent terminus ante quem which we find both above and below the first sump made their way in during flow less cataclysmic than total blockage.

Some words about the fauna...

Just like last year at the same time of year we noticed increased Guano in the cave, especially in the large chambers. I don't know what the life cycle of the bats is, or to what extent they follow the seasons, if at all. Chambers 9-12, the "screw" and the little chamber before the first sump are the places where I saw the bats gather - in the first two there is gathered guano from other years while in the last place it was the first time I had noticed bats. Here it seemed to me they were enjoying the new found space in the now empty sump and were diving into it. To judge from the dead bat some way below the first sump, some daring bats had made it across the sump and beyond. I'd like to mention a bat we had found at the highest point while surveying the first sidebranch in 2004. I draw the reader's attention to my other text on the cave mice we had found, to bring the vertebrate description to a close. They haven't been seen again since.

On to the invertebrates: There are these little guys both before and after the first sump. They're about 10mm long, white and diaphanous little critters with plenty of legs underneath. These animals are surely arthropods and quite probably isopods. They have antennae at the front but I did not have an opportunity to sit and write my comments on the spot so I forget the details. The ones in the image show the black line which runs along the full length of the animals - I assume it is the digestive system (the whole animal is diaphanous apart from this part) and seems black most plausibly because the animals in question were found busying themselves on a blackened log just after the first sump.

A little more care next time may help in identification - questions like how many legs they have per section, how many pairs of antennae, and others. Nikos tells me he has spotted cave shrimp in this cave and the chances are that this is them. Let someone correct me if I am wrong.

On to our friends the dolichopodes - which we have seen beyond the first sump but also in great numbers outside the cave at night when coming out. All the ones I have seen have been of medium size - about 40mm long. They aren't so dispersed in the cave, no doubt due to its nature as a sinkhole.

Finally - on Sunday on the way out we found a large number of well fed slugs which must have been about 70mm long and about 15 to 20mm wide at their widest.

I hope next year we will manage to record more details and have the opportunity to photograph the fauna of Dersios a little more clearly,

Some words about the results of this years explorations:

Total length of surveyed sections (30 September 2005): 1.525m
Total length of surveyed sections planimetric development (30 September 2005): 1.392m
Total depth of surveyed section (30 September 2005): 164m
Estimate of explored length (30 September 2005): ~1.800m
Estimate of the explored depth (30 September 2005): ~185m

The equivalent values in April 2005 were:
Total length of surveyed sections (April 2005): 908m
Total length of surveyed sections planimetric development (April 2005): 826m
Total depth of surveyed section (April 2005): 161m
Estimate of explored length (April 2005): ~ 1.100m
Estimate of the explored depth (April 2005): ~185m

This years exploration resulted in a 69% increase in the planimetric length of the cave in relation to last year (566m were added). The surveys have been uploaded to the photos.selas.org site here: my Dersios Album