Certainly, if you asked a worker of the time period or someone who was focused on the worker movement of the time period, "dark" and "satanic" would be appropriate descriptions. The lack of sanitary conditions, the large hours, the dangerous nature of the work, as well as the poor compensation would all fit the classification of "dark" and "satanic." The lack of light is a literal and figurative description, while the notion of an evil condition dominating much of the factory life. The fact that children were often employed for long hours and denied the rightful innocence of a childhood also speaks to the satanic and dark nature of the factories. At the same time, the violations of women's rights in terms of their subjugation that became part of the historical record of factories before government regulation would constitute as "dark" or "satanic." As with so much of history, it depends on who is being asked and whose record of history is being analyzed.
Yes.Dark Satanic Mills is an accurate description for working conditions in factories 130 years ago.