22,000 Years Ago, Aboriginal Miners Descended 70 Metres Into Koonalda Cave to Gather Flint in Complete Natural Darkness

Around 22,000 years ago, an Aboriginal miner descended some 70 metres beneath the Nullarbor Plain into Koonalda Cave. Beyond the last reach of daylight, the cave was in complete natural darkness. A burning branch or firebrand may have supplied the light. In that smoky glow, people collected and worked flint, leaving stone flakes on the floor and, deeper inside, long finger-drawn lines across pale cave walls. Charcoal found among the archaeological deposits is one reason researchers think firebrands or torches were used, although no ancient torch itself has survived.

Koonalda lies in South Australia, near the Western Australian border. Its entrance is a collapsed sinkhole, followed by a steep descent over boulders to a cave floor roughly 75 metres below the surface. From there, two main passages branch away. One contains underground lakes; the other holds most of the evidence for Aboriginal activity.

The material people sought was flint, a silica-rich stone that breaks into very sharp edges. Large nodules occur naturally in bands in the limestone walls. Older accounts routinely called Koonalda a prehistoric mine, but archaeologists now use that word more cautiously.

Much of the flint appears to have fractured naturally from the cave walls and fallen to the floor, where people selected suitable pieces and worked them. Excavations recovered thousands of pieces of flint, including large quantities of stone-working debris.

The cave does not look like a normal living site. Archaeologists found no conventional cooking hearths and very little food refuse. Instead, Koonalda seems to have been visited for specific activities. A kangaroo-skin package obtained in 1937 from an Aboriginal man about 100 kilometres west of the cave contained around 40 flint blade blanks, evidence that this kind of stone was valued beyond Koonalda itself.

Farther into the northwest passage, a huge roof collapse now blocks the old route. The rubble pile, called the “ramparts,” rises around 20 metres and has to be climbed to reach the art chamber today. Researchers think the route between the main chamber and the art area was once much flatter. Past the ramparts, no natural light reaches the walls.

Those walls are coated with a soft white carbonate deposit called moonmilk. People drew several fingers through it at once, producing long parallel grooves known as finger flutings or digital tracings. They are not fingerprints. A 2025 study describes roughly 300 square metres of wall covered by repeated wavy lines; another recent review describes about 350 metres of wall surface bearing flutings. Harder walls and fallen boulders also carry lines cut with pointed objects.

The lines do not form clear pictures of animals or people, and no one can say exactly what they meant. Archaeologists Keryn Walshe and April Nowell have proposed that the repeated movements may have formed part of ritual activity connected with the seasonal return of valued foods or trade materials. They present this as an interpretation based on broader Indigenous Australian cultural evidence, not as a literal reading of the marks.

Dating Koonalda has been difficult because cave sediments and charcoal have moved over time. A cautious range of about 22,000 to 10,000 years has long been used, while later analysis suggests visits may stretch from at least 30,000 to about 5,000 years ago.

One of the most useful finds was a detached piece of cave wall bearing finger fluting, found about 100 metres from the main gallery. Charcoal associated with it produced an age of about 18,100 years, giving a minimum date for at least some of the wall marking.

People used Koonalda during the Last Glacial Maximum, when conditions on the Nullarbor were colder and much drier and the coastline lay roughly 150–200 kilometres farther south than today. Evidence for continued human presence in this region through that period is rare. Koonalda and nearby Allen’s Cave are among the sites that preserve it.

There is another odd chapter in the cave’s history. European explorers visited its deep lakes from the late nineteenth century into the twentieth, sometimes even boating underground, yet they failed to recognise the Aboriginal markings around them. Those markings were reported to archaeologists only in the 1950s. Work led by Alexander Gallus then helped push back accepted estimates for Aboriginal occupation of Australia, at a time when some scholars still placed it at less than 10,000 years.

Koonalda is now a National Heritage place and is culturally significant to Mirning custodians and other Aboriginal people of the Far West Coast. It has been closed to the public since the late 1980s. After intruders damaged ancient markings in 2022, authorities added remote cameras and a new conservation plan. Research now includes digital recording, laser scanning, climate monitoring and water testing, carried out under tighter access controls.

Sources: 1, 2, 3, 4, 5, 6, 7