Spinning Room at the Bates Mill #3, photograph by Henri Larocque, Lewiston, Maine, 1885-1889. MHPC.S.3404
In 1887, around the time of this photograph, Maine law lowered children's work week to not more than 60 hours. That still amounted to 10 hour days six days a week.
Notice that the boys of varying ages do not wear shoes and are dwarfed by the machines they maintain.