Pumacocha Expedition Descriptions

The expedition area is reached after a full day's drive from Lima on roads that vary from excellent paved highway to dusty one-lane tracks.  Generally speaking, the area is approximately halfway between the coastal town of Cañete and the inland city of Huancayo, accessed via the gravelled road that runs between the two.  

The 2001 expedition consisted of five cavers and optimistically brought 500 metres of 9mm rope to Peru.   Acclimatization consisted of a circuitous drive from Lima over a 4818m pass through La Oroya to an overnight in Huancayo, and thence a drive back over the 4825m pass at Yauricocha to base camp at the Llapay power station.  Investigation of the sinking stream at Pumacocha soon followed.  After confirming that SP1 was too wet to enter and that SP3 was choked (though draughting) at -120m, exploration and survey commenced down the dry SP2 entrance of Sima Pumacocha.  We attempted to reduce abrasion on our 9mm rope by rebelaying off bolts and, where feasible, natural anchors.  The most notable features of the cave were its persistently vertical nature, the 113m fossiliferous Ammonite Shaft, and the dramatic entry of the main (SP1) stream at about -300m (The Shining Path).   The presence of significant falling water now slowed exploration, and the team began to run out of time at a cascade at -370m.  A probe across the stream and partway down the next pitch was achieved with the last piece of the expedition's rope.  The estimated explored depth of just over 400m made Sima Pumacocha the deepest cave in the Andes.

The 2002 expedition was a slightly larger affair, consisting of nine cavers and 1000m of rope, and again occurred over a two-week period.  As the cave was known to be 'going', rigging was a little more thorough.  Exploration and survey continued down the cascading streamway, down wet pitches as deep as 75m and past a very impressive and noisy column of water entering thru the ceiling of the passage (Viagra Falls).  Work continued to the last possible day (allowing for detackling) when a two-person team utilizing their last bolt and the expedition's last piece of rope (once again), explored and surveyed to a sump at -638m, convincingly exceeding Brazil's Grutas do Centenario as the deepest cave in South America (until surpassed in 2007).  When Sima Pumacocha exceeded -500m it also became the highest major cave in the world (4375m above sea level).  Also during this expedition the very high entrance to Qaqa Mach'ay was discovered, and its entrance pitch dropped to confirm that the cave was 'going'.  The small caves Yauricocha 1 and 2 were fully investigated, Cueva SP4 was explored and surveyed and the Puyo Valley was investigated but no explorations were undertaken.  The expedition was joined by four Peruvian cavers, members of Centro de Exploraciones Subterraneas del Peru (CESPE), who conducted surface investigations and undertook probes into the upper sections of Sima Pumacocha.

A return in 2004 for three weeks by a large team of 14 cavers, including two CESPE cavers who participated fully in the expedition, 1600m of rope and two battery-operated power drills.  With the most-geologically-likely resurgence 14km away and 1.1km lower than the entrance, hopes were high for Sima Pumacocha.  The expedition was plagued by bad weather (snow down to 4000m for the first five days) and a mysterious stomach and intestinal ailment that affected most members.  A long-abandoned aqueduct near Sima Pumacocha had been repaired in the intervening years, which aided exploration (but didn't help the photographs) by diverting much of the water from the SP1 entrance.  Unfortunately the aqueduct was quite leaky, and some water was now being delivered into the normally-dry upper shafts of the cave, making rigging and exiting SP2 more difficult. Interestingly, the large amount of water being channelled into the blind SP3 (only thirty metres from the main SP2 entrance) was not seen in the main cave until about -550m.  After several days of rigging the Sima Pumacocha exploration ended in disappointment when the main lead was found to be an oxbow back to the previously-known sump.  The SP1 stream sink was explored and surveyed to its connection with The Shining Path at about -300m, including a 282m shaft that is thought to be the deepest in the Andes.  Qaqa Mach'ay was fully explored and surveyed, establishing it as the highest surveyed cave in the world, at 4930m above sealevel.  Caves in the Puyo valley were partially explored and surveyed.

Click here to view lists of some relevant cave statistics.

A few expedition participants suffered from mild altitude sickness (headache and nausea), but most were unaffected.  All, however, felt the effects of the thinner air.  It is a curious observation that most cavers seemed to do better underground in Sima Pumacocha than on the surface.  One theory is that the exhaling draught (the opposite of what one would expect) is an indication that the cave environment is under higher pressure than the surface, with the denser cave air simulating lower-elevation conditions. 

All three expeditions benefited enormously from its sponsors and supporters which helped make all three expeditions affordable and very comfortable for its members.

For surveys and photos of each of the caves noted above, go on to The Caves, or return to the Home Page.