Swansea Vale Railway nineteenth century, when land transport was limited to what pack animals could carry on their backs. At that time the extraction of copper in Cornwall became an important industry, and as a great deal of coal is required to smelt copper, it became the practice to bring the copper to Swansea by ship and smelt it there. This specific sector of the metal industry became so dominant that Swansea was given the nickname "Copperopolis". The works engaged in this industry were located on the banks of the River Tawe at first, but the construction of the Swansea Canal, opened in
Swansea Canal culvert through large metal grids. There was a short tramway from below the lock to Ynys-penllwch Graig-ola Colliery. Mond Lock was next, with the B4603 crossing the tail of the lock. Below the bridge is the Mond Nickel Works, set up in 1900 after the chemist Dr Ludwig Mond discovered a process for producing pure nickel. Nickel ore was imported from Canada, and the site was chosen because there were supplies of anthracite coal, water, transport links to Swansea, and an available labour force. The canal crosses the Lower Clydach River on an aqueduct, which discharges water into the river,