One of the earliest was Kymer's Canal, built in 1766 to link the mines with the Gwendraeth estuary near Kidwelly, Carmarthenshire. The canal terminated in a dock, called Kymer's Dock, which in 1972, having been disused since 1809, looked like thisThe canal restoration movement, however, has not passed west Wales by and by 1990 the dock had been restored as an industrial monument and now looks like this:
In the early nineteenth century Kymer's Canal was incorporated into the much longer Kidwelly and Llanelly Canal which extended further up the Gwendraeth valley and also had a branch to the then new harbour at Burry Port some five miles further east. This branch crossed the River Gwendraeth on an aqueduct, built in 1815 and seen here in 1972.
It's not appeared on Captain Ahab's "Aqueducts of the Inland Waterways" website yet, but no doubt one day it will.
The canal only reached Llanelly (the present-day "Llanelli") by means of a connecting tramroad from Burry Port and by 1865 had turned itself into a railway company and built the "Burry Port and Gwedreath Valley Railway" (the spelling of "Gwendraeth" was wrong on the incorporating act of parliament!). The railway served the valley for another 117 years and I was privileged to travel on the locomotive (one of three!) that hauled the last coal train down the valley in 1981