Drain cover of the Koninklijke Nederlandse Grofsmederij

The Nederlandse Grofsmederij was an iron works company, located in Leiden, which didn't survive the big shake-out of the manufacturing industry in the 1970s. It was founded in 1836 by a Dutch-Frenchman William Archibald Bake who (amongst other things) fought in the Russian campaign of Napoleon.
In its heyday it employed around 700 men.

Here is a picture of the workshop of the Grofsmederij:
www.flickr.com/photos/95306653@N00/2212827614 /

Grofsmederij is a composite noun consisting of "grof" meaning coarse or rough, opposite of fine, and "smederij" meaning smithy or foundry. So the company made the big stuff, not fine ironwork.