A smaller exploration has been conducted at the end of 2021 and the first half of 2022 from cenote Abejas. This cenote is located north of Tulum, just a few kilometers outside of the town. It belongs to the Sac Aktun cave system and was first explored by Paul DeLoach and Dr. John Zumrick. This part of the cave was connected to Sac Aktun in 2004 by Robbie Schmittner (northwest, "Naval" area) and Kim Davidsson (northeast). The cave has a lot of fractures and canyon-like tunnels, being close to the sea it has a wide network of passages with porous rock and heavy percolation in untouched areas.
This project started by accident, as on a regular survey dive a decent sized tunnel has been found close to the entrance which was big enough to comfortably carry gear further to the northeast upstream section of the cave. The first survey dives have been conducted by Dr. Mario Valotta and Laszlo Cseh. As the divers collected regularly more data of the area, the discovery of the previously mentioned tunnel allowed to create a huge shortcut compared to the already existing lines leading to the same area. This encouraged the team to go further and arrive relatively quickly and with less effort to areas which seemed unvisited for the past years or even since the original exploration. The movement of the water seemed to come mainly from two directions, northwest and northeast, which created two main conduits in a "V" shape, where the tip of the "V" was Abejas and from there the water exits into the sea. Identifying this, left the divers with the thought of exploring the seemingly open area between two main waterflow directions.
Dr. Mario Valotta collecting data from old and newly explored tunnels
As the team made their way further towards the north, northeast they did a combination of survey of existing lines and the addition of smaller, new lines which created more shortcuts towards their desired area. One of the old northeast lines ended, but two survey stations backwards a small but solid hill has been observed. Once on top of it, a tunnel revealed itself which kept going for about 150 meters/ 500 feet until hitting another old line. The newly installed line turned out to be the second connection between Abejas and the northeastern area of Sac Aktun after Kim's connection in 2004. Luckily the size of the new tunnel allowed further good, backmount-sized upstream progression.
In early 2022 cave diver Cameron Miller joined the effort and picked up the exploration and survey progress of Mario's and Laszlo's work with the help of DPVs. The travel with more gear, dealing with complex navigation while even using the shortcut lines was not the most comfortable in some areas but the slowly growing distance required the use of DPVs. Very early on their first dives they arrived into an area which wasn't well visited and even older exploration lines started to become less numerous in some areas. This gave the divers the opportunity to start looking for leads into the open area they were aiming for. Many of the initial leads to the west started promisingly, but they soon hit the saltwater's level, the tunnels decreased in size and eventually stopped. Uncommon for the area, especially below the halocline, these saltwater tunnels were colored dark brown and black with a considerable amount of fine grained sediment on the floor. Being unlucky initially, the team moved further north and at any opportunity they had they tried to break into the western open region. The biggest success happened about 2 km upstream from their initial starting location. A pretty low ceiling freshwater room had a small opening on its far side. Following this lead the cave opened up into a defined but very irregular single tunnel which headed towards the northwest. This tunnel led to a highly decorated big room with a collapse on its east side. Turning slightly south from here and navigating some restrictions, another decorated room revealed itself. It took some time to figure out the correct way from this location but seemingly the cave took a hard west and kept going that way for a few hundred meters. Although the new area had plenty of cave formations it wasn't nearly as solid or white in color as classic areas of Sac Aktun tend to be. The distance to the sea seemingly changes the cave's characteristics and of course the divers weren't far enough inland for that to happen. Highly silty areas and percolation was manageable but constantly present and the team did not encounter any other cenotes along their way.
Cameron Miller swimming through the newly explored passage
For a short while the cave almost seemed to stop. The team had to navigate around a collapsed area, where luckily on the other side of the collapse the cave continued. The cave started to change and more collapses followed. One of the collapsed rooms contained prehistoric animal bone remains, including one side of a jaw. So far it is unknown to which type of animals the different size of bones belonged to, but it was definitely an interesting find! After the last collapse the cave was unable to stay in the freshwater anymore and descended back below the saltwater's level. Here the cave again became darker, kept going for a while but no flow conditions and increasingly smaller tunnels killed the possibility of exploring further. This new area started in a really promising way but after 2.4 km of new line here there were no signs left of going further to the west from this location.
Prehistoric animal bones in the new "west" area
Emőke and Laszlo wrapping up the last leads
The total new exploration distance in the area was : 3500 meters / 11500 feet with the biggest new coherent area being 2400 meters / 7800 feet.
Avg. depth: 9 m / 30 feet, max. depth: 13.3 m / 43 feet.
The teams have used open circuit GUE backmount configuration only with multiple stages and SUEX DPVs.
Longest penetration: 3 km / 1.8 miles
Average bottom times were: 5 to 7 hours with minimum decompression
New discoveries: 1 bone site and 1 new connection between Abejas and Northeast Sac Aktun.
The dive team consisted of: Emőke Wagner, Dr. Mario Valotta, Cameron Miller and Laszlo Cseh