Text and photos by Peter Sprouse

With the PEP now reaching its 25th year, it is a great time to look back on its

history and evolution. In 1978 David Honea expressed the Project's goals in a

"statement of hope and intent" which we can feel proud to have accomplished.

Those goals of excellence in speleology and respect for the area's

environment and inhabitants have guided us through the years. On my first trip

to the Purificación Karst Area in 1976, it could be described as basically

another speleological reconnaissance zone, with a few moderately extensive

caves but nothing yet major. A core group of cavers grasped its potential,

virtually moved into the area, and with the adoption of a name became the first

modern Mexican caving project. And ever since, there has been steady and

spectacular progress in developing some of the world's outstanding cave

systems. Sistema Purificación, now 95 km long and 957 meters deep, is the

longest surveyed cave in México, and other caves of the area such as 36-

kilometer-long Cueva del Tecolote continue to grow as well. Yet it seems likely

that most of the potential of this vast underground complex has yet to be

The Purificación Karst Area straddles the border between the southern parts

of the Mexican states of Tamaulipas and Nuevo León. It comprises the front

ranges of the Sierra Madre Oriental which rise from an elevation of 400 meters

at Ciudad Victoria to an altitude of 3500 meters on Cerro el Viejo, the area's

highest peak. Moderately fractured Lower Cretaceous limestones on the west flank of Huisachal-Peregrina anticline have

provided an ideal environment for development of extensive cave systems. The boundaries of the PEP study area have been

selected using major surface drainages which might be expected to limit the extent of any subterranean drainage systems. The

coastal plain forms the area boundary on the east, and to the south of Cd. Victoria it proceeds west up the Arroyo Juan Capitán

through the Huisachal valley to the Río Chihue. It follows this drainage to the northwest up the Río Alamar branch to San Pablo,

then north past El Refugio to the Río Blanco. The area boundary then follows the Río Blanco east to its confluence with the Río

Cavers first entered the high mountains northwest of Ciudad Victoria, Tamaulipas in 1971, and in the ensuing five years Texans

from Houston, Austin, and McAllen made independent forays from time to time, following the myriad logging roads through the

pine forest and exploring various caves and pits. Longest of these was Cueva del Brinco ("Jump Cave"), which had been

mapped for about 1000 meters by David McKenzie and companions. The beginnings of the PEP can be traced back to May

1976, when McKenzie led a trip back to Brinco. Situated at 1900 meters elevation in an east-facing mountain cove, the entrance

to Brinco opens into a steadily descending bedding plane passage, with regular and complex side passages leading off. In a

series of trips over a year's time various stream passages were pushed steadily downward, reaching the a major trunk passage

At the same time, a group of cavers from the Greater Houston Grotto had begun the exploration of Cueva de Infiernillo, located 5

kilometers north of Brinco and 820 meters lower in Cañon el

Infiernillo. This canyon begins abruptly at the base of a cliff

hundreds of meters tall, and 40 meters up this wall is the large

entrance to Infiernillo, a tunnel 20 meters wide and 25 meters

high. In April 1976 the Houston cavers led by Charles Fromén

led a route up into this entrance, and found a large network of

tunnels trending upward to the south, blowing air. We

immediately saw the potential for connecting the two caves, and

started the survey of Infiernillo's vast complex of passages. Due

to an access time of about 4 hours to hike to the entrance and

climb up to it, underground camps were used from the beginning

to explore and map all passages in Infiernillo. An initial complex

of ascending passages and boreholes soon led to a bewildering

maze in scalloped bedrock, the Confusion Tubes. While a route

was soon found through the Tubes to a continuing level

borehole, the Tubes themselves steadily grew into an enormous

complex which even today still contains hundreds of unexplored

Throughout 1977 rapid progress was made in both Infiernillo

and Brinco. By June 1978,we had mapped 9568 meters in Brinco to a depth of 389 meters, and 7148 meters in Infiernillo to an

overall height of 442 meters. The remaining gap between the two caves was 1300 meters horizontal and 125 meters vertical.

Camp II was established nearly 3000 meters inside of Infiernillo, and a fortuitous lead off of the Nile River area was explored

upwards into the lower reaches of Brinco. When the survey was carried downward from the Brinco end a few weeks later,

Sistema Purificación was at once the longest cave in México at 20,068 meters, the deepest cave in the Western Hemisphere at

Much of the post-connection efforts in Sistema Purificación concentrated on pushing to the south, where we suspected there

was a lot more cave and perhaps more depth to be added. An examination of the geology and passage trends of the system

suggests the prospect of extensive upstream feeders coming from the south, particularly considering that the mountain in which

the cave is formed continues some 20 kilometers in that direction and extends some 800 meters higher than the known portion

of the cave. In 1981 we put in the first camp through the Brinco entrance, Camp III, with the specific goal of pushing to the south.

This camp was a new challenge for us, 2500 meters in and 350 meters deep. Six cavers spent five days surveying from Camp

III, mapping 5 kilometers of new passage. At first we seemed to be having no luck in making major extensions to the south, but

on the fourth day we descended a fault-dip maze to the level of the Infiernillo complex and intersected a major north-south lead,

the Southbound Borehole. The last survey day there resulted in 2000 meters mapped, and we left a great lead going south. A

couple of grueling pushes from the surface to the Redrock Breakdown convinced us that we had to set another deep camp in

So in March 1986 twelve cavers established Camp IV in the Southbound Borehole, twice as far in as Camp III had been and 600

meters deep. Camp was set up in a low, wide sandy passage scattered with the ever-present death coral (tower coralloid)

common to the Infiernillo level. Survey teams worked in a variety of areas around camp,

steadily racking up more meters, but no progress could be made to the south through the

Redrock Breakdown or elsewhere. Then, as it so often happens, a breakthrough was made

on the last survey day. An obscure lead off of the newly-discovered Texas Tunnel dropped

into a southern extension, the Tex-Echo, ensuring a return expedition. One fortunate result

on the Camp IV trip was a new route found to the Infiernillo complex, allowing an easier

One year later we set up Camp V along the Nile River near the original survey connection

point of Brinco and Infiernillo. We hadn't worked extensively in this area since the

connection was made nine years earlier. Numerous leads needed to be checked close to

camp, besides the more remote Tex-Echo. This time we had 14 cavers and planned to stay

in for 10 days, our longest camp yet. Two principal south-trending passages from camp

were Goes One and Never Stops Going. Both of these yielded considerable new passage

but presented an abundance of death coral, hampering progress. Various leads off the

Goes One area earned names such as ¡Hay Chihuahua Mamacita! and God Let It End. In

Never Stops Going an arrow-straight south trend led through 2-meter-tall reefs of death

coral named Reefer Madness. Loss of blood and clothing is the only obstacle in these

The main attraction was of course the Tex-Echo at the south end of the system. About 700

meters of wet and windy new passage was mapped to another new stream, the Midnight

River. This was followed southward for 300 meters upstream to a sump, a new

southernmost point for the cave system. The airflow had apparently gone up some high leads in the canyons before the river. So

the way south into the heart of the mountain is not opening up easily, and the remoteness of this part of the cave is a major

One more attempt at following the air in the Tex-Echo was made from Camp II in 1994. Various climbs into ceiling holes only led

to pinching body-sized tubes. This trip did result in an

unexpected breakthrough near Camp II, however. An

extensive series of upper level crawls was found that

became known as No Wasted Space. These crawls

generally paralleled the main Monkey Walk passage,

but above it. The Psycho Tube sloped down to tie into

the Isopod River. The Psycho Prophylaxis went up to a

Camp II was occupied again in 1996 by 11 cavers.

Some routine mapping was done in No Wasted Space

in the gypsum filled Barber Shop, and some nice

passage was discovered off the Arne Saknussem

Borehole. The biggest push was another attempt to

break through to the south in the death coral nightmare

of ¡Hay Chihuahua Mamacita! We descended a short

drop to find a crawl that spiraled down to a new river,

the River Savage. This pinched out, but and upstream

lead led into more death coral, affectionately named

Satan's Love Nest by those involved. Naturally, it still

goes.

History