Hi Guy Kinlochleven from 1907, Fort William was built in the 1920’s.
I was fascinated by the history of the construction of these when I was a kid, particularly the narrow gauge railway involved with the Fort William one.
But the first smelter was at Foyers on the banks of Loch Ness in 1895, so aluminium from there would have initially travelled on the Caledonian canal.
What about products like jute sacking or canvas from Dundee. Barrels of salt herring, seed potatoes, Caithness flagstones.