
The photo here demonstrates that fact. Mills were built to utilize gravity. Raw ore would start "uphill" in the building. The ore would go through a succession of refining processes. This photo is the fifth and final stage of that mechanical process. From there the ore would go into a chemical bath of mercury.
It's quiet now, but I can only imagine the roar as machine vs rock duked it out all day long.
This photo was taken in mid winter, during a late afternoon snowstorm. Exposure time was around 30 minutes.