Possibly a bit old hat now, but Imperial ran expeditions to Peru in 1972 and 1984 wherein both times they explored Peru's then longest cave.
From our 25 yr history (written in 1987, so records are obviously dated) (
http://union.ic.ac.uk/rcc/caving/wiki.php?n=Main.TheFirst25Years):
In 1972 the delayed IC Karst Research Expedition to the Peruvian Andes finally took place with six members and Rog Bowser as the leader. This was a highly successful expedition doing much pioneering speleological and geological work. Notable successes were the first bottoming and survey of Peru's and S America's depest cave at -407m (the record still stands today), the first survey of Peru's (then) longest cave, as well as the exploration and survey of many other new caves.
And (Summer 1984)
This was followed by an eight person expedition to Peru, prompted initially by the 1972 expedition but based further north. Notable successes included the exploration and survey of Peru's longest cave (2.5 km) and several other caves associated with the main river cave system.
Certainly the 1972 Expo was published as a 'Journal of the British Speleological Association' CAVE SCIENCE - Imperial College Expedition to the Karst of Peru, Number 52, November 1973.
It's 34 pages of text in Quarto size, with a folder of surveys at the back, and other double-sized fold out maps.
I'm not sure what written report came out of the 1984 expedition (I could have a root around in our library if you wish), but there's some info in our 1985 newsletter on the 84 expedition, see page 7 onwards:
http://union.ic.ac.uk/rcc/caving/lib/ICCC-06-October-1985.pdf
It refers to the 'excellent written report', but I'm not sure whether I've ever seen a copy!
I'm happy to scan anything we own the copyright to & put online, if it's helpful & I can find the time.
