Australian Geographic - 09.2019 - 10.2019

PHOTO CREDITS, THIS PAGE: FRASER JOHNSTON; OPPOSITE: STEFAN EBERHARD

Cavers discover a flooded subterranean passage that sets

a new record for Australia’s deepest cave system.

42 Australian Geographic

The Day 1 party, just before

setting off: (L-R) Stephen

Fordyce, Serena Benjamin,

Gabriel Kinzler, Alan Jackson,

Stefan Eberhard (sitting) and

Fraser Johnston.

Delving into

Ta smania’s underg rou nd

F

OR MORE THAN AN hour I’d been pushing

through the silty, submerged tunnel, using the

rock walls to guide me. The water was cold

and in places the passageway was uncomfort-

ably tight. I was searching for a way through

a f looded passage deep within Niggly Cave, on the Junee

River near Mount Field National Park, north-west of

Hobart, Tasmania. I’d left the expedition team I was part

of at the edge of a pool at the cave’s end: known as a

terminal sump, it’s the furthest point cavers can access

before the tunnel becomes submerged.

I was diving alone and looking for an orange string

guideline I’d used to mark my route through a different

cave, the nearby Growling Swallet, four years earlier. Back

then, I’d dived some 500m along a narrow tunnel before

reaching the predicted limits of my breathing gas supply.

I’d severed my guideline there and secured its end to

some rocks before heading back. Now I was trying to

find that point from what I hoped was the other side.

If I could reach that old guideline and prove the two

caves were connected, our team could show that this

cave system is the deepest known in Australia.

The height of a mountain is measured from sea level

to the summit but the depth of a cave system is deter-

mined by calculating the height difference between its

highest and lowest points. So, if you’re chasing a cave

depth record – trying to find the deepest cave – it makes

sense to explore upwards, looking for high points, and

downwards, looking for low points, but it also makes

sense to search sideways.

If you can find a link between two nearby caves,

proving they are joined, then you can combine the

STORY BY STEPHEN FORDYCE ILLUSTRATION BY BARRY CROUCHER

TA S

Niggly Cave

Australian Geographic Society

Sponsored Expedition