The cave known as THE THREE SISTERS has long been known in the Mount Gambier area at least since 1933, when it was first described by scientist and explorer, Norman B. Tindale. It originally had three roof-window holes which dropped into the cavern below, but today only one of these entrances - a gated feature located just a few metres to the west of the bitumized Glencoe Mile Hill Road near Tantanoola - can be used.
Access to the cave is not simply a matter of dropping through the one metre-diameter entrance hole; there is an awkward section which needs to be negotiated for about two metres before cavers can commence the free drop from the ceiling of the pitch-dark cavern, towards the top of the large talus mound some 18 metres below. The floor drops away steeply on all sides from the apex of this mound, and visitors need to be careful not to cut themselves on the numerous glass fragments and other rubbish (such as bones from a nearby abattoir) which is scattered about in the 30-metre diameter, dome-like chamber. A few "speleothems" are prominently visible, and some large hanging curtains of tree roots around the walls give the cavern additional character.
In fact, it is important to point out that divers who are larger than "average" or who use standard steel or aluminium scuba cylinders in a back-mounted format should NOT expect to be able to get past the restriction ... a thought which must also be kept in mind if one wishes to contemplate returning to the surface as well!! Therefore, only those divers who have had extensive experience in negotiating underwater restrictions in zero-visibility should consider visiting this feature. Although the restriction takes the form of a 0.3-0.4m high and quite smooth "flattener" which is several metres long, the possibility of a diver becoming jammed during exit is very real, so all divers must be prepared - both physically AND mentally - to cope with such a situation.
Once past the restriction, divers enter the top of a large, roughly circular chamber which drops down to the right and is littered with large slabs of white limestone. The deepest point noted to date is around 35 metres, and although the dive is relatively short, the cave is definitely worth seeing at least once!