Mulu Caves ‘91

Keen to connect Blackrock Cave to Clearwater the team returned and headed south.

During October 1991 a nine-stong team returned the Park to continue the exploration of Blackrock Cave. The team included three scientists who were to carry out further geomorphological studies of the complex system of caves within Gunung Api.

Pete Boyes on the 'Sweat of Fear' traverse| photo © Dick Willis

Blackrock’s recently discovered Phoenix Series was seen to be the key to a connection with Clearwater Cave as the two caves were within 50m of eachother at their closest points. Broken Hope Hall had been the southern end of exploration in 1989 where a large waterfall had covered the south wall. The ‘91 team returned to this point to find the waterfall dry and a wide open passage  behind heading south. This rift passage broke out into a cross passage with a steep ramp heading down to a muddy area and the inevitable boulder blockage. At the far side of the cross passage a traverse over a deep pit and a rope descent led into a small meandering passage which quickly broke out into Clearwater’s West Passage. The connection had been made and the Clearwater System was now 102km long, the 7th longest cave in the world. Down the ramp an eyehole 8m up the west wall had suggested a way on. Owing to its position and relative level it was thought that this may lead into Leopard Cave. Although the theory was correct the connection wasnot made on this expedition.

The Blackrock - Clearwater Connection| photo © Dick Willis

At the southern tip of Api a small cave, Ipoi’s Cave was discovered. The cave was situated at base level and extended for only 250m. Palm Cave which had been visited by the Api 91 expedition was extended by another 680m. A slippery descent was made into lower levels which emerged into a large U tube which descended to base level only to turn and rise up to form a ‘U’ to emerge from an entrance high in the karst.

In the Deer Cave Massif an entrance had been discovered by Park staff. This was Stone Horse Cave, so named because of a large rock within the entrance which resembles a horse. This cave was situated adjacent to the plankwalk to Deer Cave and a strong, cool draft could be felt falling down the slope from the entrance 45m above. The cave was explored for 2.6km through large chambers with collapsed sediment pits in the floor.

Further exploration was carried out in Racer Cave extending the known passages by 320m. Geomorphological research centred on the collection of mud samples for paleomagnetic analysis and over 40 sites were studied between the resurgence and the 400m horizon.

For further information log on website :
http://www.mulucaves.org/wordpress/expeditions/mulu-caves-91