Coal breaker remaining. The sorting by size is particularly important for anthracite coal. In order to burn efficiently, air must flow evenly around anthracite. Subsequently, most anthracite coal is sold in uniform sizes. In the 1910s, there were six commercial sizes of coal (with the smallest size having three subsets): Coal pieces smaller than in size were considered "culm," and unable to be separated from the impurities (and thus useless). The grade of coal ranged from a low of 5 percent impurities for steam or broken coal to a high of 15 percent for pea-size coal and its subsets. Coal breakers were
Coal breaker breaker already sorted into its respective sizes, was collected primarily by rail cars and then delivered to market. Coal breaker A coal breaker is a coal processing plant which breaks coal into various useful sizes. Coal breakers also remove impurities from the coal (typically slate) and deposit them into a culm dump. The coal breaker is a forerunner of the modern coal preparation plant. Generally speaking, a coal tipple was typically used at a bituminous coal mine, where removing impurities was important but sorting by size was only a secondary, minor concern. Coal breakers were always used (with or without