Dewi Llloyd, Katrina Hawkins, Pete Hambly and myself are just back from an excellent two week caing expedition to the Purificación Karst Area of Mexico. This is located to the west of the city of Ciudad Victoria and is about 12 hours drive from the US Mexican border. The main cave in the area is the 90+ km long Sistema Purificación - the longest cave in Mexico. It also offers one of the greatest through-trips in the world with 895m between the top and bottom entrances. This trip takes underground about 30+ hours although it only has two short pitches in it. It also takes a lot of surface logistics to achieve. To quote the Atlas of the Great Caves of the World, the through trip in Sistema Purificación is "the perfect example of an underground journey".

The expedition was organised by Proyecto Espeleológico Purificación (PEP) - an organisation run by a group of cavers based in Austin, Texas, who run regular trips to this area. For this trip, the team totalled 28 cavers (5 British, 2 Irish, 1 German, 4 Canadians and 16 Americans).

The expedition spent a week at Conrado Castillo adjacent to the Cueva del Brinco (the usual entrance for Sistema Purificación) extending and surveying known caves in that area and also prospecting for new caves. The second week was spent in the Tinajas valley about 5 km west of Brinco. This area had been little visited in the past but a small trip earlier in the year had found a number of promising leads.

During the expedition, a number of new caves were explored and mapped in the Conrado Castillo area and also yet more leads were checked out and cave surveyed in the main Sistema Purificación.

In Tinajas, numerous small caves were mapped (some within a stone's throw of the campsite). Sima de la Chupacabra (discovered in April 1997) was explored and extended to a sump at -400m. The cave is mainly vertical with some very fine long pitches, made even more exciting when rigged on 8.5mm new PMI rope. The cave draughts strongly and the draught is assumed to come from one of the avens just prior to the sump - a possible sump bypass, although bolting will be needed. Also explored and surveyed was Pozu del Lantrisco (-150m approximately, a mainly vertical cave with an 80m pitch from the surface ending in a shaft blocked by boulders with no significant draught.

Acknowledgements to Proyecto Espeleológico Purificación (PO Box 8424, Austin, Texas 78713, USA), Peter Sprouse and Susie Lasko for their organisation, Bill Mixon for driving 4 British cavers to Mexico and back, the local Mexicans at Conrado Castillo and Tinajas for permission to cave in those areas and for showing us cave entrances, and all the participants for two weeks of very enjoyable caving.

Bibliography:

Lasko, Susie and Sprouse, Peter (Ed.), The Death Coral Caver, No. 7, October 1997, Proyecto Espeleológico Purificación

Courbon, Paul et al, Atlas of The Great Caves of the World, Cave Books, St. Louis, 1989

Various (ed), AMCS Activities Newsletter, Numbers 1-21, Association for Mexican Cave Studies, Box 7672, Austin, Texas 78713, USA

Tim Palmer