Cave divers have officially discovered the second-largest known cave in the Limestone Coast at Mount Gambier’s Engelbrecht Cave.

Local cave diver Josh Richards first discovered the extension of Engelbrecht’s East with his buddy Matthew Aisbett in December 2019.

“Before we went, another more senior cave diver turned around to us and said there is a bit of water at the back of the air chamber,” he said.

“It is essentially a very short swim and then you surface in this large air chamber and if you clamber over about 50 or 60 metres of rock you will get to this other little pool at the back.

“Matt and I decided to go and have a quick look and while we were splashing around in the back having a look at it I shone a light up to the roof and there was a very strange reflection.

“It turned out the reflection was an air chamber, and so we surfaced in the air chamber and found a room past it, like a dry cave room.

“We squeezed in there and found a little puddle at the back of that and squeezed through the puddle and it turned into more chamber.

“That is kind of how it all started, we found this cool, fairly large water-filled room after we had squeezed through a few different bits and pieces.”

The cave runs from Engelbrecht Cave directly towards the Cave Garden/Thugi and Mr Richards said he was almost certain the two caves would connect.

Mr Richards said when he moved back to Mount Gambier at the end of 2020 he completed some further training and ventured back into the cave to inspect the unusual feature they discovered.

“I realised there was a fairly significant tunnel running off in a very strange direction that we had not noticed previously,” he said.

“From there it has just been a progressive process of dive, push a little bit further, run in more line, find more tunnel, come back out, go in with more line, keep laying and keep surveying, mapping this thing out progressively.

“There is still more to be discovered but we have sort of reached a point where we suspect anything further is going to be much harder work than what we have found so far.”

Mr Richards said although they had known about this for a long time they could not share it until recently and the discovery was officially announced at the Cave Divers Association annual general meeting.

Mr Richards said discovering the second largest cave in the Limestone Coast was very surreal and it was exciting and relieving to finally share the news with people.

“It was very exciting at the time, when we first spotted this tunnel and followed it down and kept going, we were really in shock if I’m honest,” he said.

Mr Richards said people had been diving Engelbrecht’s East for the last 50 years however it was overlooked due to being such a short dive.

“So to suddenly discover more than 400m of new tunnel beyond that was just very surreal, every time we looked somewhere further you would see a hole somewhere and it was leading somewhere else that you had not seen previously,” he said.

Mr Richards said parts of the cave were fairly dangerous, including entering the cave itself.

“There are two sections to the cave, it is all one cave but we have essentially split it into a western branch and a southern branch,” he said.

“The western branch is incredibly pretty, it is relatively open and large and it is easier to navigate, but the southern branch is some of the worst cave I have ever seen, it is very pretty but it is brutal.

“There is footage of me in a wetsuit and tiny little centimetre cylinders wriggling backwards and forwards and having to exhale to squeeze through some of these things.

“The southern branch is pretty lethal, so we are not encouraging anyone to go down and dive that.”

Mr Richards said the region was riddled with caves and tunnels running underneath the entire town and region.

“This is one, in the scheme of things, relatively small cave compared to what we have got running around underneath Mount Gambier that people do not know about,” he said.

“A bit of hard work and squeezing into places that people have not been to before and suddenly these magical, extraordinary places open up that you have got no indication from the surface that it is there.”