Swansea Canal coal and culm shipped from Swansea Docks suggest around 386,000 tons in 1839. The opening of the Tennant Canal to Swansea Docks in 1824 resulted in the Swansea Canal's riverside wharfs being improved, and tolls were reduced to maintain trade levels. The harbour facilities at Swansea were upgraded in 1852, when the river Tawe was diverted into a new channel to the east, and the original channel, which included the trans-shipment wharfs, became a floating harbour. A lock was constructed to give the canal boats direct access to the half-tide basin above the North Dock, and a loop of the
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,