I don’t hear the hum in my east Windsor stomping grounds, but I heard it loud and clear recently playing in a charity golf tournament at Essex Golf Club.
It sounded like a locomotive lumbering down the tracks or the rumbling of distant thunder, but it was consistent and it actually seemed to pulse — like the hearbeat of an alien!
There is a very old and ugly blast furnace, located in Detroit. It is just opposite residential housing in Windsor, Ontario. It was abandoned for a time, and restarted in 2009.
A blast furnace takes ore and coal, and shoves in the top. Hot gas and extra air goes up through the bottom
I couldn't find much on vibration monitoring for these things, but the vibration is intense for a run. The run ends when the tap hole is blown, and the hot melted iron is poured out.
It's difficult finding things that aren't sucked up by Elsevier. As you are aware, they have bought the US gov't for a few million bucks, to extend the paywall, and thus enrich their pockets.
I'll continue if there is any interest.
