Introduction

First discovered sometime in the early 1980’s by an enthusiastic band of unqualified local divers, Iddlebiddy Cave was named as a tongue-in-cheek nod to Cocklebiddy Cave on the Nullarbor Plains, which Iddlebiddy resembles in structure but not in size. The location of Iddlebiddy Cave remained a closely guarded secret for several years, until it was first formally surveyed on 26 November 1988 by Tony Hambling, Frank Homewood and John McCormick on behalf of the Cave Divers Association of Australia.

A narrow vertical solution tube drops four metres onto a platform which divers can use to gear up, before climbing down a short ladder to the water. The main tunnel heads south-east as a single passage nearly 200 metres long, roughly 12 metres wide and 5 metres high. Several tighter off-shots from this tunnel were explored by divers through the 90’s and early 2000’s, however the tight and silty conditions in these side passages offer only limited potential exploration.

Line Survey and Photogrammetry

Given the large and relatively straight nature of the main Iddlebiddy tunnel, the Soggy Wombats decided it would be an ideal cave to further develop our photogrammetry experience in a relatively simple and safe cave. Before starting with a photogrammetry project though, it’s essential (and sometimes easier) to get an accurate line survey of the cave in first place. One of the great features of the MNemo is that it provides a quick sense of the direction the cave is heading and it’s rough length. Grubby Wombat was the first Wombat to play with the first available version of the equipment back in 2019 (MNemoV1). More recently, he has been using the MNemoV2 in our projects. You can find more information on how to use MNemo in your own projects in our article.

A New Hope – The Iddlebiddy Extension

While the team was engaging photogrammetry dives to map and build a complete 3D model of the cave, some other wombats were poking around in the lesser explored sections of the Iddlebiddy Cave. Grubby and Weirdo were the first ones to break through the new surface lake (southeast of the entry solution tube) after conquering the spine bending restriction called the Trash Compactor. The surface lake is big enough to accommodate a few divers to catch their breath after the restriction and it was named Base One.

The hole new section added similar length to the main tunnel. Around 200m of line was laid in very narrow and silty passages. The end of the New Hope extension has three main potential leads, which the Wombats haven’t got through completely yet. The Star Destroyer might return to the surface lake, which would shorten the trip as well as make it safer; Hoth area has two potential leads pointing to the correct region fault line compass bearing, and have higher exploration potential.

All collected data was reverted into a complete 3D model and a brand new map for the Iddlebiddy Cave. This map has been released in December 2023 and is available in high-res upon request (just send us an email).