In March 2019, Rumble Chasm was linked to Grove Cliff Fissure by enlarging a too tight rift to produce the longest and most arduous through trips within the Grove Cliff Caves. The section through Rumble Alley and Rumble Chasm consists mostly of awkward passage and typically slow progress. A very dodgy choke on route adds a little flavour. This section of the cave is no place for novices.
To complete the through trip from Allotment Dig entrance, follow the description for the Allotment dig to Grove Cliff Fissure through trip until you reach Rumble Alley Junction. Instead of turning left towards Grove Fissure entrance, continue straight ahead along Rumble Alley. Initially, follow at floor level until 3 ascending chock stones provide a convenient way to climb up higher into the rift. Follow the rift from the top of the chock stones past a tight rift to your right. After 4 m the floor lowers; however it is easiest to continue by traversing the rift at this height approx. 3 m above floor level using a narrow ledge on your right for feet. After 5 m descend approx. 1 m onto an obvious wedged boulder at a cross rift and then to floor level. One again follow the rift at floor level. Please keep to the above described route through this section to preserve the very attractive gold and silver moon milk in the untouched parts. After approx. 10 m a too tight rift is found on your right. This marks the break-through point into Rumble Chasm. Continue to wriggle along the rift and then through a squeeze to regain a taller rift. Descend the wedged boulders to find another tight rift to your right. Continue straight ahead through an obviously enlarged passage approx. 3m long to find a junction at a tetrahedral boulder. Straight ahead ends after 7m however the way on is through the squeeze to the left in front of the boulder. The rift now opens out and you find yourself high up on a false floor. Descend to floor level using good but friable ledges. Unfortunately the rift narrows lower down. Continue ahead through a low section beneath a very dodgy choke. Extreme care should be taken not to touch anything here, especially when emerging into open rift on the other side. The rift now takes a slight dog leg left where it is necessary to climb up 1.5 m and traverse over a blind hole in the floor. Continue ahead to a left turn into a narrower section of rift approx. 4 m long. The rift then turns back right handed and is followed to a man-made wall. Either squeeze through the hole atop the wall or climb the rift 1 m before the wall to find a ledge which can be crawled along to avoid the squeeze. Continue to crawl over the 'flag-stones' to arrive on the far side of the walled section where it is necessary to descend 3 m to floor level. The rift is then followed easily up hill for a further 15 m to the entrance. A pair of bolts can be found on the right hand side to arrange an abseil exit (10 m). A 25 m rope is required for a pull through.
Trip time approx. 1 h 45.