01 August 2011

Tar Tunnel, Coalport

In 1797 William Reynolds, ironmaster, drove into the north bank of the River Severn what is now known as the tar tunnel, intended as an underground canal to link his Madeley coal mines to the river. When the bitumen was revealed the tunnel's purpose changed; collected in pools (below), the bitumen was taken out in wagons - 4,500 gallons per week at peak.

This was used to treat rope for the caulking of boats and, in a refined form, made into Betton's British Oil, sold as a remedy for rheumatism. The tunnel is understood to be about 1,200 yards long. The public are admitted to the first 100 yards, the point of the lamp looked back to at top, where there is a locked gate.

The tunnel is lined throughout most of its length, the bricks just one deep, remarkable given the shallowness of the arch, which widens in one part to enable wagons to pass each other. Beyond a solid flood barrier with metal hatch is a section of unlined tunnel. The floor here is particularly clayey, with oil floating atop the water. Bitumen extraction ended in the 1840s, and the tunnel was extended to drain a number of mines. The final section easily explored is in the form of a brick-lined conduit (above).

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