What is "breaker boy"

A breaker boy was a coal-mining worker in the United States and United Kingdom whose job was to separate impurities from coal by hand in a coal breaker. Although breaker boys were primarily children, elderly coal miners who could no longer work in the mines because of age, disease, or accident were also sometimes employed as breaker boys. The use of breaker boys began in the mid-1860s. Although public disapproval of the employment of children as breaker boys existed by the mid-1880s, the practice did not end until the 1920s.