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
Bituminous coal sulfur, and other impurities as possible. The constituents of the coal should be as follows: Cannel coal is a coal which ignites easily producing a bright flame. The name derives from the Scottish pronunciation of "candle coal". It contains a high volatile content, is non-coking and was a source for coal oil in West Virginia during the mid-1800s. While the use of Cannel has greatly diminished over the past century, it is still valued by artists for its ability to be carved and polished into sculptures and jewelry. When used for many industrial processes, bituminous coal must first be "coked"