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Tunnels in Port Adelaide: Separating Fact from Folklore

Tunnels in Port Adelaide:
Separating Fact from Folklore

Stories of secret passages beneath Port Adelaide circulate persistently — linked to smuggling, escaped convicts, and illicit trade. The physical evidence, however, tells a different story.

Stories of secret tunnels beneath Port Adelaide circulate persistently, often linked to tales of smuggling, escaped convicts, or illicit trade. It is an appealing idea — but the historical and physical evidence does not support it.

Three obstacles that made tunnelling impossible

Port Adelaide was built on swampy, waterlogged ground. Any tunnel construction in the colonial period would have faced three near-insurmountable obstacles:

  • I Unstable, saturated soil — the ground required continuous shoring simply to prevent collapse, making any tunnel an engineering undertaking of the highest difficulty.
  • II No suitable timber — while red gums were plentiful in the region, their characteristically twisted grain made it impossible to mill them into the straight, uniform planks that tunnel shoring requires. No local timber would do the job.
  • III Continuous pumping — keeping a tunnel dry would have required constant water removal. With only manual pumps available in the colonial period, this was not a practical proposition on any sustained basis.

The conditions that made Port Adelaide's early years so difficult for surface construction would have made underground construction effectively impossible.

"The same swampy ground that plagued every early builder in Port Adelaide would have defeated any tunneller before they got very far."

The one documented tunnel

Research conducted by the PAHS Historian found evidence of only one tunnel in Port Adelaide. This was located at the base of the Copper Smelting Company's chimney stack, where a flue tunnel was constructed to increase the effective draw height of the chimney — a recognised engineering technique of the period.

Cross-section diagram of the Copper Smelting Company chimney flue tunnel A cross-section showing how a buried flue tunnel connects to the base of the chimney stack, increasing its effective draw height. Ground level Furnace Chimney stack Flue tunnel (below ground) extends effective draw height Effective draw height Visible chimney height

The flue tunnel added to the total column of hot gas driving the draw, so the chimney performed as if taller than it visibly appeared. This was its only function — an industrial feature, not a passage for people or goods.

Why the stories persist

The tunnel stories are part of Port Adelaide's folklore, and like much good folklore they say something real about how people imagined the port's rough-and-ready past. The colonial port was a place of hard labour, transient populations, and activity that did not always bear scrutiny. It is the kind of place where tunnels ought to exist.

But the physical reality of building beneath a swamp, with colonial-era tools and materials, tells a different story. The ground itself was the most effective obstacle to any would-be smuggler's imagination.