Slate was discovered at Willunga in 1840. For the next eighty years it built the town and roofed half of South Australia. The miners were Cornish, the village they founded was named after a slate town in Cornwall, and the legacy is still visible in the streets today.
A discovery in 1840
In 1840, four years after South Australia was proclaimed a British province, a man named Edward Loud noticed a slab of dark blue stone sticking out of a hill east of the new village of Willunga. He recognised it instantly. The stone was slate - the kind that splits cleanly along natural cleavage planes into thin, flat sheets, the kind that had roofed Cornish villages for centuries. Within months, the first commercial slate quarry on the Australian continent was operating at the foot of that hill.
A Cornish workforce
The miners who came to dig the slate were Cornish. South Australia in the 1840s was already importing skilled Cornish labour by the boatload - the copper boom at Burra and Kapunda was in full swing - and Willunga's slate offered another use for their distinctive set of skills. Cornish quarrymen knew how to read a slate face. They knew where to drive a wedge to split a block cleanly along its natural plane, how to trim it to size with a curved knife, and how to grade it for roofing, flagstones, billiard tables and school slates.
They settled in Willunga and built homes from the same stone they were quarrying. The most concentrated of their settlements was named Delabole, after the famous slate village in north Cornwall - a piece of homesickness pressed into the South Australian map. By the 1860s the slate quarries around Willunga were producing more roofing material than any other source in the colony, and the names on the deeds and the headstones in the churchyard were almost all from Cornwall.
What they made
Willunga slate was good slate. It was hard, fine-grained, resistant to weathering and split with a clean dark-blue face. It was used for roofing tiles all across South Australia, for the flagstones of public buildings, for billiard tables exported interstate, and for schoolroom writing slates that ended up in classrooms from Adelaide to Perth. By the late 19th century the quarries were exporting slate to Melbourne, Sydney and reportedly as far as India.
The technique was unchanged from Cornwall. A quarryman would identify a working face, drive iron wedges along the cleavage line, lever a block free, then sit at a stone bench and split it down with a hammer and chisel into the thinnest sheets the rock would tolerate. A skilled splitter could turn a single block into dozens of usable tiles. The work was hard, the days were long, the lung diseases were inevitable, and the wages - by colonial standards - were good.
The decline
Willunga slate ran into the same wall every Cornish slate town eventually hit. Cheaper imports - first from Wales, then from Spain and Italy, then from concrete tile factories - undercut the price of locally quarried slate to the point where the Willunga pits could not compete. By the 1920s commercial quarrying had effectively ended. The miners moved on, the pits filled with rainwater, the village of Delabole faded into the surrounding farmland.
What survives
The slate is still in the ground, and you can still see it everywhere in Willunga. The 1855 courthouse is built of slate. So is the old police station, the slate roofs on a dozen High Street buildings, the flagstones around the Soldiers Memorial and the kerbs along the main road. The National Trust's Willunga Slate Museum, in the old courthouse complex on High Street, tells the full story - quarrymen's tools, original company maps, photographs and the ledger books from the long-vanished company stores.
The quarries themselves are mostly on private land but a few interpretive signs on the edge of town point to where they once worked. And up the road, the Cornish surnames are still in the local phone book.
