Deep cave exploration – a view from the logistical side

The continuing exploration of particular Cenotes, cave systems and sinkholes within the Yucatan Peninsula takes time in terms of divers committing to exploration with training and experience, the financial as well as the time burden that such explorations are coming with. Another large aspect of cave exploration is finding the right dive team that is equally experienced to dive the cave or sinkhole at hand, to train continuously and work up to the planned dive pluis the logistical support needed for such projects.

decompressing deep diver

Decompressing deep diver

In January of 2010 all came together when a polish deep diving team around Jurek and Cezary were ready to continue the deep exploration of the Sabak Ha (Turbid Water) Cenote in the central Yucatan some 60 kilometers / 40 miles south of Merida. I was diving deep in Sabak Ha around 1997 – 2000 to a depth of 150 meters / 500 feet with a large room clearly continuing horizontally as well as vertically down. No walls where to be seen, no ceiling and no bottom with a visibility of around 30 meters / 100 feet. When Jurek heard about this site we went for a recon dive earlier this year ,and he was all for a project to push the boundaries.

lowering gear to the water

Lowering gear to the water

The 2010 exploration team consisted of Jurek and Cezary as deep push divers, Robert and Dariusz as support divers, Conrad filming underwater, Jacek and Piotr filming on the surface. me from the ProTec Dive Center in Playa del Carmen was responsible for local support, logistics, gas mixing, photography underwater and on the surface, liaison with local authorities and press as well as translation. All participating divers where technical cave divers as well as Trimix divers experienced in deep cave diving as well as Mexican cave diving. Dive team preparations prior arriving in Mexico included multiple deep cave diving in the Red Sea in the 100 – 120 meter / 330 – 400 feet range to get the team procedures in sync. When the dive team arrived in Q. Roo during the beginning of January 2010 three days of horizontal cave diving in large doubles where conducted to acclimatize to Mexican caves and the tanks to be used during the deep diving project.

For the first deep diving day in Sabak Ha all breathing gases such as a number of Trimix mixtures, Nitrox and oxygen were mixed by me in Playa del Carmen’s ProTec Dive Center. A total of 25 80 cft alm stage tanks, 2 sets of 80 cft alm double tanks, 2 sets of 104 cft steel double tanks and 2 sets of 125 cft steel doubles tanks got filled, rigged and came along for the trip. This was going to be an all open circuit assault as all divers where experienced in open circuit deep diving. The project was scheduled in a way to dive one day then mix gases / rest the next day, dive one day then mix gases / rest the next day, and so on.

mixing it up

Mixing it up

After arriving on site at the first diving day all came together as we met our porter team around Dionicio and Chepo from the Ecology Department of Yucatan who introduced us to the helping hands they had organized. The 2010 Sabak Ha exploration project was in the planning for over 6 month with continuous support from the Ecology Department of Yucatan who contributed with a rescue team and vehicle on site. As all gases where mixed in Playa del Carmen the team went to the dive site for a recon dive that led the whole team to a depth of 65 meters / 215 feet. During that time one camera man was diving with the team documenting the environment, two camera men stayed on the surface documenting the surface activity and I me remaining on the surface organizing the surface support as well as taking still images for later articles that where to be published in Poland.

gear assembly

Gear assembly

underwater camera man

Underwater camera man

The next day after the recon dive was a mixing day with a 6 hour long mixing session at Dutton’s Machine Shop in Merida, the only filling station in Merida. During that mixing session a number of breathing mixes did not turn out the way they should have been. The affected breathing mixtures were analyzed and identified the same evening but could not be changed due to fill station time restraints and gas supply company hiccups, the gas company not being able to deliver the gases I had reserved and they had confirmed. The blending issue was identified to as helium tanks containing less than 100% helium. The average helium purity was established and analyzed around 93-94% helium, with one tank 70% helium and another 80% helium. This mix up of breathing gases could have been easily avoided if I would have analyzed all helium tanks for helium content before starting the mixing process. In order to fix the breathing mixtures the next planned diving day fell into the water as the remixing of a number of Trimix mixtures took some 3 1/2 hours as soon as the filling station opened, and at this time the dive team did not feel it wanted to be rushed into deep cave diving, and canceled the dive of this day.

fill station in Merida

Fill station in Merida

The second diving day lead the deep diving team to the 100 – 110 meter / 330 – 360 feet horizontal passage from where the line leads into the large room where no walls, bottom or ceiling can be seen. When continuing into this passage exploration starts at 120 meters / 400 feet horizontally and when following the line down at 150 meters / 500 feet depth at the end of the line with no bottom in sight. The deep team was continuously documenting the whole dive with a helmet mounted video camera. The shallow diving team went into the shallower 65 meter / 215 feet cave passage to investigate the potential for further exploration. During that dive the underwater camera man was filming the deep team to a depth of 100 meters / 330 feet while this author was taking underwater still images to a depth of 30 meters / 100 feet as well as surface photography.

Due to delays with the gas company providing the helium and oxygen, and the weekend becoming a major factor of not being able to blend breathing gases in the fill station the day was used to shoot surface footage at the Uxmal ruins. Nice day, nice footage, not much diving through. At this time the project schedule started to slide but the day in the ruins was a great way to not think about diving too much.

The following day started with fully restocked helium and oxygen supplies and the next 6 1/2 hour mixing marathon session began to blend breathing gases for the upcoming push dive. This time we had no bad helium tanks but all tanks were analyzed to be around 93 – 94% helium. While being at the fill station all day long I really appreciate the help from Elias who helped me so much pumping all that air that was needed to drive the so important booster pump as well as to top of all them tanks.

tanks come up the line in darkness

Tanks come up the line in darkness

The next diving day came with us leaving Merida around 8:00 am from the Tecnotel Motel right in Merida and close to the fill station with about an hour’s drive to the village of Mucuyche where we met at the house of Dionicio and Adelaida to gather the rest of our porters. Today old trusted Pedro came along to help out, bringing the porter crew up to four porters. Arriving shortly after 9:00 am at the dive site it took about 1 1/2 hours to get all the tanks set up, down the rope and towards the water’s edge. The rescue teams daily arrival was around 11:00 am, just before the divers went into the water. The hang line was installed daily to hang travel gases, deco gases and extra tanks onto the line prior the divers went into the water. Support divers verified the tank depth. During the deep part of the dive one of the deep support divers got entangled into the guideline at around 100 meters / 330 feet depth and the guideline had to be cut to free the support diver. At this moment the dive was called and the divers came back to the surface well before the 6 hour long planned dive that would have been the push dive. Better safe than sorry.

tanks come up the line in darkness

Tanks come up the line in darkness

As the project time was running out slowly with the project duration coming to an end it was decided to do one more dive to fix and repair the guide line at 110 meters / 360 feet in order to leave an continuous guideline for following dive teams. Breathing gases where filled and remixed early in the morning the same day with a late start arriving at the dive site at 11:00 am putting the divers into the water around 13:00 pm. The deep diving team was able to repair the line on this last dive and to push on into the deep part of the cave to a depth of 130 meters / 430 feet. As we had a late start into the dive darkness came up fast. The generator was started up around 17:00 pm providing light with two 500 watt working lights, thus enabling the surface crew to safely bring all the tanks back up the line and stored into the vehicles.

During our stay we gave a number of interviews for local news papers and local TV stations that demonstrated that the local populations interest in how the sinkhole of Sabak Ha, the deepest geological feature of the Yucatan may continue and what new passages might be found. During the diving days we had quite a large number of up to 40 visitors that came from the surrounding villages to see what we do, have a chat and lend a hand.

As the project came to an end the team did no reached the goal they came here to Sabak Ha to fulfill, the exploration to maximum depth, however, the team established the potential of exploration at the 120 meter / 400 feet plateau. When the guideline broke it became a priority to repair the guide line and they spend a dive on repair instead of a deep push dive. During the four conducted deep dives no one was hurt, no one was bent, not even a strained ankle, shoulder or scratch on the arm. As it turns out at times deep cave exploration is not an easy feat but if you can walk away from it and talk about it, it was a great successful project. The dive profiles where for dive 1) to 60 meters / 200 feet, 20 minutes bottom time, 1,5 hrs total time, dive 2) to 60 meters / 200 feet dive, 30 minutes bottom time, 2,5 hrs total time, dive 3) to 113 meters / 370 feet, 17 minutes bottom, 2 hrs 15 minutes total time, dive 4) to 100 meters / 330 feet, 11 minutes bottom, 1,5 hrs total, dive 5) to 130 meters / 430 feet, 30 minutes bottom, 4,5 hrs total time.

decompressing deep diving team

Decompressing deep diving team

I would like to thank the Ecology Department of Yucatan for their support, the Bomberos rescue team to be there for us, the porter crew to make it happen, Adelaida for the great Yucatecan food, Pedro to not give up teaching me some Maya and Dionicio to have the great skill to move a mountain of equipment without a scratch.

I would like to thank the Polish deep team Jurek and Cezary, the support team Robert and Dariusz, the underwater camera man Conrad, the surface film crew Jacek and Piotr to come here to Mexico and trying to push the known boundaries of these deep caves. I would like to mention as well that part of making the project happen was the generous project support of the main sponsor Infovide-Matrix a Polish IT consulting company which also sponsored Jurek’s 231 meter / 757 feet depth record in 2007, the main media patron National Geographic Poland and the equipment sponsored by Liquivision – X1 Trimix computers and Ammonite Polish underwater lights.

family matters

Family matters


1 Rossen { 01.28.10 at 1:54 pm }

Wow, a great report Mat! Good to see some familiar faces on the photos.

2 Andy Pitkin { 01.28.10 at 8:28 pm }


Great report. It sounds like the logistics gods were not on your side, and it shows how difficult deep expeditionary diving can be in remote locations. Sabak-Ha is an amazing place, and it sounds that while the team did not explore as far as originally intended, there was never any compromise in safety margins. Do you think rebreathers might be logistically easier? Many are being dived to the 150+ metre depths seen in Sabak-Ha. Anyway, thanks again for the report and pictures.

3 Matt { 01.29.10 at 6:16 pm }

Family matters … the last image at the end of the article is my adopted family in Mucuyche, they adopted me as their son. Dionicio and Adeleida, really sweet people. They call me Chicitito – the smallest one …. 🙂

4 Matt { 01.29.10 at 6:20 pm }

The good Doctor .. great to hear from you. I am going through the old images quite a few times when we went diving there in the last milenia. Even with the goals not reached I feel the project was a success as new information was gathered, other confirmed and the deep cave diving team did detailed recon on the deep part.

5 Juan { 02.02.10 at 5:13 pm }

Matt, great report! It give us a good sense of what implies for deep cave exploration.

Saludos de Guadalajara!

6 Margaret { 02.17.10 at 5:31 pm }

Thanks for the great report!

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