Descent of a cave man

Mammoth challenge ... much of the cave system remains unexplored.Credit: Ben Stubbs

Ben Stubbs conquers his fear, plunging 120 metres into one of Australia's most challenging cave systems.

I stand at the edge of the cliff, shaking inside my blue jumpsuit. To my left is a 90-metre chasm. Treading carefully, I use my fingers for grip while I follow the torch in front.

There is something about male bravado that prevents us from admitting fear, failure or inability. When I was offered the chance to go ''adventure caving'' in one of Australia's most challenging caves, I didn't think a trifling detail - that I had never been in a cave - would matter.

In 1884, not far from Katoomba in the Blue Mountains, there was a man who had a similar compulsion to jump in at the deep end. Jeremiah Wilson discovered a fissure in one of the cliffs not far from the Jenolan Caves. Inside this man-sized hole was a cave system that is now known as the Mammoth Cave. Wilson grabbed a candle and jumped into the darkness to see where it led.

Here I am, 126 years later, hoping to see what Wilson discovered. The Jenolan Caves management body that organises the adventure expeditions allows only 10 people a month inside the Mammoth Cave. Two cavers with a wealth of underground experience at Jenolan, Rebecca Lewis and Alison Fenton, are leading our group.

We unlock the grid at the entrance and enter the darkness. As we slip down the first slope into the complete blackness, I decide now would be a good time to confess to Fenton that this is the first time I've been caving.

She laughs: ''You've got to start somewhere … might as well be from the pointy end.'' She explains that when I'm moving along a difficult section I should always aim for three points of contact on the cave for stability.

We head down through the looping Jug Handle section, guided by the yellow beams of our head-torches. Along silent limestone arteries we reach a stack of smooth boulders, called rock piles, that blocks our path forward, so I have to bend like a contortionist to squeeze through. Then I'm into the next section - on my stomach, snaking through the mud and close to the backside of the caver in front.

We bond quickly as a group and begin pack-passing the gear through the difficult sections to ensure we maintain our momentum.

Now 120 metres below the surface, we play Chinese whispers to relay instructions from the front. Fellow caver Daniel passes on the instructions: ''Feet first off this drop-off, put your right leg out until you find the ledge and then grab the rope with your left hand.''

We pause beside a clump of stalagmites and Fenton and Lewis instruct us to switch off our torches. My eyes can't adjust to the darkness here; it's impossible to see something even centimetres from my face. I tune into the echoes, the gush of an underground river in the distance, the slight breeze and the drip of water from a stalactite above. Fenton uses the darkness for effect and tells us that when Wilson first explored the Mammoth Cave in the 1800s he would get lost regularly. On one unfortunate outing, his candle extinguished and he was lost inside the cave for three days before he felt his way back to the exit.

Just in case I have to lag behind for an unexpected toilet break (for which we're given bottles), I ask Fenton what to do if I get lost. ''Sit right where you are,'' she says, ''turn your torch on to low and wait for someone to come find you. Oh - and don't dwell on the fact that you're alone in a cave hundreds of metres under the ground.''

We hit a dead end beyond the Oolite Cavern and I look into the black hole below. The only way out is up. Fenton grabs the nine-metre ladder latched on the lip above us and shoots up into the limestone chimney, out of sight. I grab the ladder and hang suspended in the darkness, aware of the fathomless void beneath me. How deep is it? I've no idea. I hug the swaying metal rungs with my hands and kick up with my heels, step by step. Halfway up the chute I bounce off the wall with my shoulders and my foot slips. Keep breathing, I tell myself, and I continue hoisting myself up until I see Fenton's hand hanging over the edge, ready to grab me.

We stop for lunch in The Aven, a multi-coloured chamber in the Mammoth system that vaults 90 metres towards the surface. I eat my sandwiches in the dark. When I flick on my torch I notice dark blotches on the walls. Fenton says these are the 430 million-year-old fossils of brachiopods, which lived inside shells.

Nearing the climax of our exploration, we stop on the lip of the aptly named Skull and Crossbones section, which is on the edge of a pitch-black cliff top and the end of Wilson's expedition. Etched on the wall is the triumphant marker left by Wilson on February 22, 1884, along with an ominous finger pointing ahead. I throw a stone off the ledge and wait for it to land. Seconds pass before I hear a faint clatter hundreds of metres below. Fenton tells us that much of the Mammoth system is unexplored.

Nearing our seventh hour under the ground, the walls seem to be moving in and I see fatigue on the faces of the other cavers. We climb along the Horse Shoe, across slippery ladders of limestone, careful to keep three points on the ground at all times. Eventually I see a spring in Fenton's step and she points towards a familiar tunnel.

There is a collective intake as we reach hot, fresh air. Just as Jeremiah Wilson probably exited this cave as a wreck of nerves with a wet candle in his hand 126 years ago, I shake with relief when I see the sky.

Ben Stubbs travelled courtesy of Tourism NSW.

The Jenolan Caves are a 2½-hour drive from Sydney. The Mammoth ''adrenalin adventure'' is run on the first Saturday of the month and is limited to 10 people aged over 16 with average fitness; previous caving experience is recommended. The trip costs $175, including all gear. See www.jenolancaves.org.au.