Supplied: Tim Muscat
Supplied: Tim Muscat

More than a watering hole

Located in the middle of a sheep grazing paddock on a farm located 10 minutes from Mount Gambier, Kilsby Sinkhole is an amazing natural wonder with a unique and fascinating history.

Once little more than a watering hole for traveling stockmen who would throw a bucket into water below and haul it numerous meters back to the surface to quench the thirst of their cattle, the sinkhole has since been central to 4 generations of the farming activity of the Kilsby Family.

A divers delight

Driven by the curiosity of the content of the shimmering crystal-clear water of the chamber below, the site was one of the first sinkholes to be dived in the Mount Gambier region, with recreational diving activity commencing in the late 1950’s. The site attracted a large number of people who flocked to the site on news of its natural beauty and renowned water clarity.

Valerie Taylor dives in Kilsby’s sinkhole at Mount Schank during filming for The Cave Divers in 1966. Supplied: John Harding

Despite being far from their core-business, in recognition of the interest in the site, the Kilsby family has continued to welcome divers to their property through a variety of access structures over the years.  The family has a long standing relationship with the Cave Divers Association of Australia (CDAA) who were pivotal in demonstrating sustainable access based upon safe diving practices and respectful site management principles.

A training site

The site is used as a training site by the South Australian Police Divers who return to Kilsby Sinkhole annually to complete a variety of exercises.

Emerging from Kilsby Sinkhole: police divers use the natural site for deep dive training. (ABC Local : Kate Hill)

Each year, diving instructors utilise the perfect training environment at Kilsby’s to deliver a range of recreational and professional diving courses on behalf of agencies and associations such as PADI, TDI, SSI and the CDAA.

Weapons research

Barra night testing courtesy dsto.defence.gov.au

In the early 70’s, the use of the site took an unlikely twist as the Kilsby Family were approached by the Government to use the site for weapons research, in particular the classified testing of Barra Sonobuoys – a monitoring tool which could be deployed from aircraft and helicopters to detect, locate and classify quiet submarines and surface ships.

The presence of the Weapons Research team resulted in the installation of significant infrastructure on the site including a large gantry system across the sinkhole at ground level, a workshop and platform. A diving bell was positioned on the water surface and a dry cylinder providing underwater viewing of the testing area at depth was installed on the southern side of the site.

Tests would require the deployment of sonobuoys at pressure into the water, resulting in a noise which resembled a small explosion, reportedly rattling the windows of houses over a kilometer from the site. During these periods, lights would flash, sirens would sound and, due to the secrecy of the tests, an armed guard was positioned at the entry to the site.


View from depths towards surface testing platform. Supplied: www.rancd-association.com
Barra Sonobuoy test tower and viewing cylinder at Kilsby Sinkhole. Supplied: www.rancd-association.com

Current status

These days only the workshop shed and the cement footings for the gantry system remain at the site, with the ground level platform removed for safety reasons in mid 2015.

The workshop now fulfills an important role for the site as an undercover change space, kitchenette and classroom for courses delivered at the site.

In 2016, the Kilsby Family intend to develop permanent toilet facilities onsite, re-clad the shed and redevelop the ground level viewing platform.

Increased access
In addition to the site access traditionally only enjoyed by members of the Cave Divers Association of Australia, the Kilsby Family has commenced the provision of a range of trial site access agreements to recreational diving entities. This trial comes after years of broader industry push (diving industry, tourism and education sectors) for reform to the way in which access to privately owned sites such as Kilsby’s are managed.

This trial has already provided access to a limited group of recreational diving entities, school groups and land based tour operators.

Unlike the access which has been extended to the CDAA, non-CDAA bookings require all divers to access the site under the supervision of an industry recognised guide (i.e. Divemaster/Instructor) who represents the entity holding an access agreement. The ongoing access to the site is directly aligned to the integrity of these guides, their commitment to follow the protocols of their represented agency and their diligence in following site access guidelines.