Surveying in Mammoth Cave, 12/29/2023 - 12/31/2023
Cavers: Eugeniya, Rory, Gabe, Kat, Michelle
By Eugeniya
Going to Mammoth Cave was an exciting and new experience for all of us! Firstly, Mammoth is the longest known cave system in the world! (And we got to go into it!) Secondly, we were surveying with the Cave Research Foundation (CRF). This meant that we were helping make a map of the cave, both going to places that people hadn't visited ever before (or at least not recently) or visiting places where the maps were badly connected and where more survey needed to be done. It was really exciting to be able to help out with mapping Mammoth!
Getting to Kentucky was an adventure in and of itself. We began with Rory, Michelle and me starting in Boston. We rented a car and drove to NY, where we met Kat and Gabe and stayed the night. After that, we drove 12 hours to Kentucky to get to Mammoth. Finally having arrived, we eventually found the CRF accommodation we were staying at. While we would be surveying on Saturday and Sunday, we actually arrived on Thursday night and were able to go caving on Friday as well.
On Friday, two MIT alum (and tripleaders), Boof and Felipe took us into a cave that isn't part of the Mammoth system, but is also in this area! It was very cool to see the differences between New York caves and Mammoth. Also, since Kentucky is warmer, and this cave was dry, we didn't have to wear wetsuits and were even able to be somewhat too warm in this cave. This was very unusual... We eventually headed back, and talked to the expedition leader, and were assigned various trips for Saturday.
Michelle and I went on a trip to tie in survey points. What had happened previously was that multiple people had surveyed and the newer survey hadn't in any way linked itself to the older survey. Then the cartographer who was trying to make a map of this region was left with a series of disconnected surveys to try and make into a map, but no understanding of exactly how they connected. Our task was to go into the cave and find survey stations on both the newer and older survey and connect them. This involved measuring the distance between the points, the azimuth and inclination, since this gives enough information for the cartographer to connect the points.
Thus, bright and early on Saturday, we all got up, had breakfast and headed into the cave. A lot of the trail we were following was actually a tourist trail. We were able to walk along turning on and off the tourist lights! The cave was very different to New York caves we had been to. The cave was a lot larger, with massive tube passages. There was also a lot of gypsum in the cave, which is a white mineral that forms in caves, and appears in many different forms, such as gypsum snowballs or gypsum flowers. They are really pretty and you can see photos of them in the photo gallery! It was really really amazing to see all of the gypsum formations covering all of the walls!
Eventually, we got to the spot where we were connecting survey markers. These survey points consisted of a variety of things, such as carbide marks, sharpie marks, whiteout marks, poker chips or other such objects. We had previous survey data, and using information such as the distance from the walls, ceiling and floor, as well as the approximate location from a hand drawn sketch we wandered the cave looking for these markers. Usually, we'd have a couple of options of which survey point to find, but they were still very difficult to spot. We were lucky to be able to find a handful of them and be able to connect them! Eventually, we ran out of time, and had to head out of the cave and go back to our bunks. There we met the rest of our MIT friends, who had gone off together to survey a small cave not connected to the Mammoth system, but due to some complications along the way, weren't able to actually do any surveying in the end. We then had dinner, although not everyone came back for dinner -- some of the trips went out to further reaches of the cave and didn't end up getting back until 5:30am!
Waking up on Sunday morning, we found our assignments for the day. This time round, we were assigned to more trips that were going into Mammoth Cave proper (as opposed to the small cave that half of us had gone to the day before) and surveying new and unexplored cave! Gabe and I ended up on a trip together, that was going to try and survey some leads that they had in a passage. These were places that people noted that there might be more cave, but they were fairly tight and unpleasant, so no-one had bothered to survey them so far.
This time, we didn't follow the tourist trail. Along the entrance there were many various obstacles that we encountered, including squeezy and bendy passages, very wide open passages that we walked through, some places where we had to do some climbing (including a place where our tripleader had warned us that they'd been on a trip where someone had fallen and dislocated their shoulder). It was very fun going deeper into the cave, and travelling for a handful of hours to get to a place that hadn't been surveyed. It was also interesting being in a larger cave, where the cave around us changed, sometimes being big and sometimes being small, sometimes being vertical canyons, at other times being tubes, and resembling a subway tunnel. Once again, there was lots of pretty gypsum and other formations including ones that we hadn't really seen in New York caves! Along the way we also learnt lots of things about the cave, including how to read scallops to determine historic water flow, the different layers of limestone (Mammoth is quite deep and spans three different limestone layers) and how to tell that you're on the boundary of them, and also things about cave mapping software.
Very close to our end destination, we noticed that there was a hole in the ceiling of the canyon passage we were passing through. We looked at the map, which did not note this as a lead. We had found virgin passage that the previous survey had skipped over! We'd found a part of the cave that no-one had mapped, and that hadn't been on the list of unmapped things to go map! This was very exciting. While we still got to our destination, we decided to survey the ceiling hole we had found.
We discovered that getting up there was rather difficult. It involved chimneying up the canyon-y passage we were in. A canyon passage is what it sounds like -- it's an underground canyon, which is tall and rather thin. Unfortunately, the walls were not very stable, and would crumble if you put too much force on them -- this meant that chimneying up them still worked, but as you moved on the rock that you were pushing against would crumble under you. This was a rather disconcerting experience. Additionally, while where we started chimneying were were only a handful of feet above the ground, the hole was over a much more exposed part, where the canyon went down and the drop was around 30 feet if we fell -- something we very much didn't want to do since getting out would be rather difficult if anyone got injured. We were able to (mostly) climb up into the hole and do some surveying!
Surveying usually consists of three roles -- the sketcher, who draws a map of the cave as you go along; the point person, who sets up survey points and determines where the survey is going; and the instrument person, who measures distances between subsequent survey points and tells the sketcher so that they can record them and use them to draw their sketch. In this trip, there were four of us -- and usually, the trips seemed to be 3 or 4 people, occasionally going up to 6 if there were two directions to survey so that the trip would be able to break into two groups of 3. Since there was four of us, we did have one extra person, but I got to be point and Gabe got to be instrument person, with one of the experienced people hanging out between us to help us out with any questions, and with choosing survey points.
To measure distances, azimuth and inclination (the distance, NESW direction and elevation change -- the three measurements needed to determine the relative location of the two points) we were using measuring tape and suuntos, analog instruments that you look into to identify the angles. Some of the other trips people went on used digital instruments (which are now more commonly used), where you are able to shoot a laser at the next point and then it automatically measures distance, azimuth and inclination for you. As the point person, I was able to use the instruments to take some measurements! Being the point person also meant I got to climb ahead and look around. This included climbing ahead of everyone when we got to the last survey point to describe what the area ahead looked like. I was also able to set a handful of survey points, which was also very exciting. I really enjoyed being the point person!
Overall, we all had a great time at Mammoth Cave and learnt a lot of things about surveying as well as getting to see a much larger and grander cave. It was lots and lots of fun! This is definitely my favourite cave I have been to so far! There are also lots of cool photos you should look at on the photo page!