By Andy Chapman

This year, I was given the chance to join the Mexpe expedition to the Sierra Negra region of Mexico, in order to survey and explore the cave Tres Quimeras to it’s resurgence.

Myself and Imogen Furlong had arranged to meet the rest of the expedition team in the Mexican city of Tehuacan. The first obstacle to achieving this was getting there without either of us speaking Spanish. The problem was fortunately solved when the plane was landing. I saw a scruffy looking man who appeared to be wearing a t shirt with espeleo written on it, we had met our first expedition member!!
Luckily, Eric could speak fairly good Spanish, so we managed to get to the chosen destination and book a hotel room. We met with the rest of the expedition, (most of which were French speaking, causing hours of confusion for the British team members throughout our time together) and went out for Mexican beers.
Mexicans have a penchant for Chilli and so we were intrigued to taste Michelada, a beer served with Chilli, lime and salt around the rim of the glass. After one sip, both myself and Imo had decided this may be the most disgusting beverage we had ever tasted but having paid just under one pound for it, it was going to have to be drunk. We did not make the same mistake when ordering again.

After spending about 2 days shopping, we headed to base camp near a small village called Buena Vista. This involved being bundled on a 4 by 4 pick up truck, in the blazing sun and being driven up a rock strewn road. Halfway through the journey, I discovered by wedging my legs underneath a pile of tackle bags, I could avoid being unceremoniously thrown out of the vehicle, saving an unwanted visit to a Mexican hospital.

We arrived at the campsite and looked around at our home for the next month and all agreed it looked idealic. Situated at the bottom of a valley, with shelter from trees and a small stream babbling it’s way through the campsite, everyone agreed this was an exceptionally nice place to stay.
However, this was to be our undoing. The shade of the trees, the protection from the elements of the valley and the presence of the water made it the ideal playground for mosquitoes and other bloodsucking insects, making swatting insects a chief activity of the holiday.

The cave required re-rigging as the rock was fairly loose and any bolts from previous exploration may have fallen out or could be very unsafe so a number of days were spent reaching the last surveyed point which was at the depth of -500 metres. Once this had been completed, exploration could commence.
Expedition caving works in a slightly different way to normal caving. The cave must be surveyed as you explore so rushing down to the bottom of the cave without surveying would be considered very bad form. However, if a cave has a great deal of rigging to be done then obviously, this must be done before it can be surveyed. Therefore, a pushing team would be split in 2 parts, with one person rigging and the others surveying.
The surveying could be done, using a number of different methods. Clinometers, compasses and tape could used to give the bearings, direction and length of passage which would then be written in a notebook to be drawn as a survey at camp or alternatively, a distometer could perform all these tasks and then bluetooth the information to a Palmtop, cutting out a lot of work.
Once a certain depth had been reached, an overnight camp was required to allow further exploration. Luckily, as the cave was comparatively warm, no shelter was required and you could make do with a sleeping bag and a carry mat and enjoy a mosquito free night. Because mosquitoes are fairly reliant on their eyesight to find suitable victims, there was a distinct lack of flying insects underground. However, the alternative was worse!!
The University of Mexico City had offered the expedition a certain amount of funding to capture samples of cave scorpions known to be resident in these caves so most pushing teams had taken sampling bottles full of alcohol and devised ingenious methods to capture the poisonous creatures without touching them. Some team members had developed a sealing system for their oversuit legs, using car inner tube to prevent any invertabrae scuttling up the trouser leg and causing permenant disfigurement. This ensured that nights underground were spent anticipating scorpion attack, rather than resting for the next day.
It was decided for two teams to push the cave, one from the main entrance and another to aid climb the resurgence to try to meet in the middle. A pushing team went down to -800 metres and marked their last survey station with some pink marking tape and started back on the 12 hours trip back to the surface. The team reached base and collapsed, shattered from the arduous return journey only to be greeted half an hour later by the resurgence team, clutching the pink tape and a box of Mexican beer. They had been 15 minutes from the resurgence and had turned back!!
The cave had been connected to the resurgence and surveyed in just under a month, so it was decided to spend the last three days in Mexico City, relaxing, celebrating and drinking, all of which were done to a high standard and level of accuracy!!
To conclude, expedition caving is slightly different from normal “tourist” caving, but it does give the opportunity to explore virgin passage and to see some of the most spectacular caves. I would recommend going should you be given the opportunity to participate. Just remember to pack insect repellent!!