Cambridge Underground 1982 pp 38-44

Mexico Spring 1981


Readers of the caving press, especially Caving International, will no doubt be aware that great things are being discovered in Mexico, but are probably less aware of the great variety of the areas being explored. The following introduction is intended to place the Mexican discoveries in context as a background to the spring project in which I participated.

Cave exploration has been going on for many years, in the main by US cavers, which led to the formation of an informal group called the Association for Mexican Cave Studies (AMCS) whose rôle now is to collect and publish information on the caves of Mexico and to co-ordinate trips to avoid duplication of effort. It is recommended that any group planning to travel to Mexico should be in contact with the group, based in Austin, Texas.

Mexico map - 75 dpi, 24k gif

As cavers explored into the karst of Mexico, it was natural that those regions nearest the main roads should be the first to come under scrutiny, and the earliest AMCS Bulletin "Caves of the Inter-American Highway" reflects this. A series of limestone mountain ranges along the El Abra reef trend - the Sierra Madre Oriental - were explored, the most promising of which were the Sierra de Guatemala south of Ciudad Victoria, the El Abra south of Ciudad Mante and the Xilitla Plateau. The latter area contained the deep pits of Sotano de las Golandrinas and El Sotano - the largest free drop pit in the world.

Further south, the spectacular karst plateau of Huautla de Jimenez was discovered, leading to the exploration of the deepest caves in the Western hemisphere - Sotano del Rio Iglesia and Sotano de San Agustin. Trouble with the native population led to a self-imposed moratorium on exploration in the area for ten years. South West of Mexico City, a large area in Guerrero and Morelos contains such famous caves as Grutas de Cacahuamilpa.

More recent explorations have penetrated further from the main highways both in the north and the south, and further exploration has continued in the other areas. To the east of Mexico City, the Cuetzalan area has yielded long river caves with huge passages, several streams converging to give Mexico's second longest system. Much further south, exploration in Chiapas, mainly by Canadians (including many expatriate Brits) has been rewarded by such finds as Sumidero Yo Chib, at the time of its exploration probably the most spectacularly and dangerously wet cave in the world. In Huautla, the renewed exploration has found a series of deep caves, all close to connecting into one huge system. The first of the connections came when the very deep Li Nita was connected by diving to Sotano de San Agustin to yield a system 1220m deep. This area was also the scene of a very serious rescue when a Polish caver broke his back deep inside San Agustin. Further south still, expeditions have penetrated into Guatemala and Belize.

In the north of the country, the northern end of the Sierra Madre Oriental was penetrated by long dirt roads, and when exploration of the area started, the rewards were considerable, leading to the discovery of the caves which were eventually to form La Sistema Puricación, which is still being explored by an AMCS under the direction of Peter Sprouse and Terri Treacy.

La Sistema Purificación - History of exploration

The cave is located in Ejido Conrado Castillo in the mountains north west of Ciudad Victoria, and was known to the local populace long before the arrival of the American Cavers. The Historic Section of Cueva del Brinco shows signs of a considerable history of investigation, so when members of the AMCS first arrived in the area in the early seventies, they were quickly directed to the entrance and the potential of the area was realised. On subsequent visits, they were shown a large, inaccessible cave entrance in a cañon headwall about three miles away and 850m lower. When the entrance was reached, the huge passages of Cueva de Infiernillo were seen for the first time and the dream of a connection was established.

At the start of the spring trip of 1978, Cueva del Brinco had been surveyed to 6.5 km long and 257m deep, while Infiernillo was 4.6 km long. A third strongly draughting cave, Sumidero de Oyamel, had also been found the previous autumn. During the Spring Project, a huge trunk passage with a stream, The World Beyond, was found in Brinco which was heading away from Infiernillo, but after a mile or so, it abruptly turned about and dropped steeply. After the spring trip, Brinco was 9.2 km long and 382m deep, already a significant cave. Oyamel was just over 1km and 125m deep.

Exploration fever set in, with a return to Infiernillo in July (nominally the wet season) in which the cave was surveyed to 9km, and passages were explored which had to be very close to Brinco. In again from the Brinco end, and flagging tape was found which could only have been placed by the Infiernillo crew - on July 13th, the connection was surveyed and Sistema Purificación was born: 20.086 km long and 884m deep, the longest and deepest cave in Mexico.

A trip in December saw the system's first accident, when a caver fell and broke his leg in the recentlky discovered Valhalla section of the cave, but a remarkably smooth rescue organised from the USA saw the injured man safe after three days in the cave. The spring project of 1979 saw more surveying in the phreatic mazes of the Confusion Tubes area in Infiernillo and the discovery of Moria, an important lead toward a postulated Great Western System. It also saw a 20 hour through trip with Claude Chabert and Paul Courbon, who then dug out a new top entrance to the Valhalla region - the Entrada de los Franceses. At the end of the spring, the cave was almost 28km long.

Useful infomation was gathered on the system in flood when 19cm of rain fell in a storm in December, when the sumps at the bottom of the system were seen to be 64m above their dry season level. In spring 1980, attention was returned to Oyamel, which was surveyed to 2.5km and then connected in to the upstream end of the World Beyond. At the end of 1980, the system sttod at 38km long and 895m deep - by far the longest, but no longer the deepest in Mexico.

area sketch map, 27k gif


From Ciudad Victoria we headed towards the mountains. Rounding a steep bend, a vista opened up on the right, of the Cañon Infiernillo, in the steep headwall of which is the massive entrance of Cueva Infiernillo, the bottom entrance to La Sistema Purificación. As darkness fell, we arrived at Conrado Castillo, which was to be our base for the next seven weeks.

The first trip into the Sistema was via the Entrada de los Franceses, an entrance into the highest part of the system, Valhalla, a complex fossil phreatic maze in somewhat crumbly rock. The first part of the cave is generally dry and we caved in jeans and shirt-sleeves down a series of low passages and then many climbs, always leading down over solutionally etched rock in wierd forms. One or two parts of this area are quite narrow, and as we were carrying quite a bit of gear, our progress was not too fast in the warm cave (generally about 15° in the upper part of the system). A change of character in the cave to firmer, darker limestone somewhat reminiscent of OFD was closely followed by the sound of running water, and we soon emerged at roof level above a five metre climb into Valkyrie River, a recently discovered stream passage whose source was unknown and destination only conjectured.

We unpacked gear and got changed into wetsuits in the roof passage and then climbed down into the stream. Upstream through beautiful blue dolly tubs and then a series of shallow lakes led to a wide sump pool held back by extensive gravel banks. Here Randy Rumer donned a mask and tried freediving with an electric lamp. The roof levelled off at about -2m in very clear water but Randy needed a large rock in his wetsuit to get enough weight to go further. A small bell about 2m in had no air and as the sump could be seen to go many metres in crystal visibility he retreated. Don Coons dived a couple of times finding nothing new, but the visibility started to deteriorate, so we decided to head downstream to survey in going leads.

Downstream from our entry point, deep canals in blue water with calcite encrustations made pleasant, if cool, going to a sump with a bypass. Shining lights underwater identified a probable freedive which would cut out the bypass, but it wasn't attempted. Instead, we split into two parties to survey. Peter and Terri went with Don Coons and Sheri Engler to follow the main way, whilst Randy and myself with Del Holman and Jerry Atkinson set off into side leads. These unfortunately degenerated into very muddy grovels where surveying was very grotty, leading to the name 'Mud Point Mud Mud' and we were not too disappointed when all ways closed down or sumped. We retreated to the surface, emerging at 3.15 am, after thirteen hours underground, whilst the other group had to give up in good, blowing cave, and surfaced a couple of hours later.

Activity was now directed to a planned week long trip to Camp 1 in Infiernillo to explore leads in the lower part of the system. Since the cave entrance is halfway up a large cliff at the head of a cañon about an hour and a half from the nearest road, and major leads are up to 5 km inside the cave, camping is almost obligatory. A long trek down into the cañon led to the base of the cliff.

Peter ascended to the cave and rigged a pitch down to the arroyo to ascend and haul. It was during the hauling that Peter's pack broke loose and crashed down the tyrolean into a boulder, wiping out one set of surveying gear and all our water purifier. Once we were all assembled in the 20m high entrance, it was getting quite late, but it was only a half hour trek in huge passage to Camp 1 in a side passage above a large static sump.

The first day from Camp 1 established a general pattern as we split into three surveying groups working in different areas. The American style of exploring new caves is the only one possible in an area with so much open and going, so we started surveying into virgin passage, eventually extending this area down to the first running water found at Gnome Springs.

The second day out, we went into Moria, the westernmost area of the lower cave - near base level, and with a powerfully draughting choke heading towards the postulated Great Western System. Whilst Jerry placed a substantial charge on a selected boulder, I frantically fetched mud to pack it, and we soon had an impressive bomb ready to go. The satisfying bang put both our lights out, but once relit, we wasted little time in inspecting the damage - the fumes having already cleared in the draught. Several boulders no longer existed, and I was soon demonstrating the British liking for digging by trundling large amounts of decimated rock out of the choke, but after a couple of hours it became apparent that no further progress could be made without a proddling bar, so we retreated - digging could be quite frustrating at the rate of one bang per year.

On the next day a "Glub Glub" trip was planned into Isopod River in which a small stream had developed into a canal downstream. This meant heading along the route toward the top of the system, climbing up into Confusion Tubes - where junctions abound in all directions. Emerging through Lakeland into South Trunk, we trogged along for half an hour in a huge mega-trunk to a bouldery area which got quite thrutchy. We were distracted in the Breakdown Maze by a possible way on through the boulders which Peter thought might cross over into downstream Isopod River, and when Duwain and I opened up a route down to a deep blue canal we decided to survey it. This soon proved abortive in one direction due to low airspace, and the other way eventually led back to known passage, so we tried a dry route which turned out to be an alternative route through the Breakdown Maze back toward Infiernillo.

On day four, Jerry and I planned to return to Gnome Springs with Don and Sheri, but when we got to Misty Borehole, we decided to look briefly at an unpushed climb at the end of this tube. Whilst Sheri and I formed the opinion that the climb was quite impossible, Don tried out a few moves and suddenly shot up the wall, into a hole and out at roof level, much to our surprise. He then traversed over the top and into going passage and vanished for some time, only to return with news of a major borehole. We hurriedly rigged a handline and ascended to start surveying.

The rift above soon turned into a tube and then developed into something unusual for the cave - a classic keyhole passage some 2-5m deep below a 2m tube. There were lots of side leads, but the main way carried all the air and we emerged into a sizeable tube. Unfortunately this didn't continue too far before a large flowstone blockage, but a side passage led to an area with cave ice pools and bacon rind stal, from where a beautiful flat flowstone floored tube ascended steeply to a series of climbs. Here we met a small stream depositing calcite which we thought could well feed Gnome Springs, but the water sank into a tiny vertical tube and our route was up the small waterfall into another tube almost blocked by flowstone.

The water came from a small passage but the way continued to a deep rift in the floor which we traversed, past a pom-pom stalactite to a climb down into an increasingly complex and muddy area. Here we ran out of time and after a short run ahead we headed back to Camp 1, pausing only to name the area Ithilien. Back at Camp 1 we found that the "40 kilometre" party had taken place on the assumption that we had bagged enough booty, but that we had been so long that everyone had crashed out.

Owing to lack of motivation, and illness, day 5 was declared the last day of the camp, so we decided to get as far into the cave as possible in two groups: one finally getting into Isopod River and one to take photographs in the Netherhall - a very large chamber about two and a half miles into the system. Beyond the Breakdown Maze, the South Trunk continued very large again to the turn off to the lower Isopod River where the wet team were getting changed. We left them and headed into the Monkey Walk, an awkward stretch of passage with low roof and bouldery floor, leading eventually to the Isopod River, a large passage with a small stream meandering between gravel banks, and containing colonies of troglodytic isopods like little piles of white rice in the stream, which gave the passage its name. By traversing the few pools which blocked the passage, we were able to reach the site of Camp 2 on a shingle bank with dry gear, and from here we started to climb up immediately to reach the Netherhall, which contains a 150m high boulder pile - like climbing Great Gable at night. After about half an hour of upward slogging on scree, we reached the summit and spread out to get an idea of scale before spending the next five hours taking photographs.

outline survey, 14k gif

Brinco Camp 3

The next major project was Camp 3 - set up for the first time in the upper cave, about 350m below the Cueva del Brinco entrance and 3km inside the cave. As the entrance series of the upper cave is much smaller than Infiernillo, but also wet, we had to arrange for gear packs to split into smaller units and be completely waterproof. As this was a new camp, it was thought best to have a supply run to set the camp up, followed by a lighter trip to move in any gear which didn't make it first time.

Despite its proximity to the fieldhouse, this was the first time I had been into Brinco, but with the heavy gear, we were all moving slowly, so I had a reasonable chance to look around. The first part (the Historic Section) is roomy and dry with many dead formations. We descended a fair way, mostly in steep passage but with a few climbs, until we reached the Dressing Room. This is where the fun starts with a wet thrutch, The Chute, followed by a narrow fissure, The Crack of Doom. This was quite time consuming with large packs, but once through, progress in the Lunar Way was faster, though strenuous, until another delay at Mud Ball Crawl. Beyond, the passage opened out into Rio Verde, a steeply descending streamway with steep gours and deep green pools, leading pleasantly to Flowstone Falls, a 20m freeclimb which we, however, rigged with a line to facilitate descent with heavy packs. The falls drop straight into a swimming canal and further cascade before a series of squeezes obstructs the way. Another steep climb led to the beginning of The Canal - a low airspace wade in muddy water. This ended in a climb up and over a barrier and through a lake to the Speedway Bypass - a somewhat awkward passage breaking out dramatically at The World Beyond.

The World Beyond is a major trunk passage carrying the largest stream in the system directly away from the resurgence for almost two miles. The going varies from deep swims of up to 100m, to a meandering stream among gravel banks, to climbs over large scale collapse. This ends abruptly where the stream, augmented by a major inlet (possibly Valkyrie River), cuts down to the right to form the Angel's Staircase, eventually sumping at -600m. The main way on to Infiernillo and Camp 3 is to the left starting a series of steep climbs over rotting flowstone with a major change of direction at a pitch. Shortly below this was the site of Camp 3 - a roomy chamber with a coarse gravel floor and a couple of deep pools. Here we dumped the gear and had a rest before setting out for the surface.

It was 3 days before we set off for the real camp. The first 3 days underground turned out to be relatively unproductive. On day 3 we reached a complex junction area from where our route turned out to be a dead end. Returning to the junction, we followed footprints into a large maze area, Medusa's Maze, which descended down the dip of a major joint to an area with attractive formations.

On day four, both parties worked in and around the maze, extending the area downwards until stopped by a large phreatic lift going steeply up, The Wall, which proved rather loose at the top. Below this, however, we found yet another downward lead into smaller passages but with a strong draught. This area, Yawndwanaland, continually stepped north, then down dip, then south along the strike, then down dip and so on, moving slowly west on balance until at the end of the day we reached a steep climb down. Louise went to investigate, and found that it dropped into a major north-south passage which must by now be both deeper and further west than the main route to Infiernillo.

As this passage seemed to offer the major breakthrough needed to extend the system at depth under the ridge to the south, where sinks lie up to 1600m above the Infiernillo sumps, both parties were fielded into it the next day. We elected to survey north while the others went south. Our lead, Death Coral Rift, headed dead straight in a high rift floored with death coral, a sort of muddy calcite encrustation that seems to grow in passage annually flooded with turbid saturated water which drains slowly. We shot leg after leg, mainly easy and long, until we came to a shattered chamber. Climbs led to more bouldery passage, still heading north, until we came to a conclusive, but draughting choke apparently close to the Netherhall. From here we headed back the 800m we had surveyed to see how the others had got on. They had surveyed over 1200m in generally large draughting passage heading south all the way. This passage was now nearly as far south as the southernmost point of the system. We returned to camp elated after fourteen hours, and discussed stretching food supplies to allow one survey team to carry on south. When Peter, Terri and Louise set off next "morning" however, they quickly returned, having found the system was in flood. This meant that the World Beyond would be difficult, but more important, the Canal might be sumped. Roy, Patty and I set off for the surface immediately, while the others packed up their camp gear. As might be expected the return was made somewhat hairy by the flood conditions. We were met by Jim Pisarowicz just inside the entrance as we emerged just before midday after 10 hours caving. We crashed out quickly in case we had to take a food stash for the others as we were sure that The Canal would soon sump behind us; but in fact the others came out about three hours after us, having dumped some gear at the World Beyond. We learned from Jim that almost four inches of rain had fallen in the previous three days, as the start of the wet season was approaching.

While Camp 3 was busily succeeding, Jim had not been idle, having spent the time in surface prospecting on the ridge to the south. Of several holes he had investigated, two looked particularaly promising, situated above the area that the new Camp 3 passage was heading for, and we soon set off to investigate these. The smaller pot, Pozo del Peso, choked at -36m, the deeper, Sotano de la Rama, reached a choke at -140m. After this, Jim and Louise left, leaving just Peter, Terri and myself to spend the final week in sundry pursuits - retrieving the gear from the World Beyond, surveying in some of the smaller local caves and surface surveying, before returning to the US.

The Spring Project was pretty successful, extending the system from 38km to 45.5km, closely challenging Easegill in the world length stakes. A lot of extremely high quality caving was done and I would like to express my most sincere thanks to Peter and the Proyecto Espeleologico Purificación for allowing me to join them in 1981. I hope to be able to return to assist in future years in this magnificent system.

Andrew Waddington

A longer version of this article also appeared in the Northern Pennine Club Journal, 1982

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