The phrase "satanic mills" refers to factories or industrial buildings that are depicted as evil or harmful. It signifies the negative impact of industrialization and the mistreatment of workers during the Industrial Revolution. Full definition
Blake's dark satanic mills play a large part in Power from Steam by Richard L. Hills (Cambridge University Press, pp 338, # 17.95. (newscientist.com)
The 19th - century satanic mill quality of the content farms contrasts with the insensate machines that rid spamming of the human element. (scientificamerican.com)
Blake arrives in Machine and reports to the Dickinson Steel Works, a dark, satanic mill where he expects to be employed as an accountant. (rogerebert.com)