What is "powder mill"

n. mill that manufactures black powder (gloss: type of gunpowder)

A powder mill is a mill where black powder, a type of gunpowder, is made.

Powder mills were driven by a power source such as windmill, water mill or horse mill, and contained rollers for grinding or a pilon for pounding the ingredients of gunpowder together, as well as presses and tumbling barrels and sieves for compacting, granulating, drying, grading and packaging the powder. Powder mills were built with an eye towards mitigating the danger of explosion, usually with one or more walls built purposely weak so that the force of an accidental explosion could be directed towards an open field or a river.

In 1802, the DuPont family started their industrial enterprises in the United States by building the Eleutherian Mills on the Brandywine Creek in Delaware. This was the start of large-scale gunpowder production in America, supplanting what had been primarily a cottage industry.

The place where the finished powder was stored was called a powder magazine or powder house.