The following sizes are shipped from the breaker: Broken, or Grate coal, which passes through 4-inch mesh, but not through 2.5-inch mesh.
Egg coal, which passes through 2.5-inch mesh, but not through 1.75-inch mesh.
Stove coal, which passes through 1.75-inch mesh, but not through 1.25-inch mesh.
Chestnut coal, which passes through 1.25-inch mesh. but not through .75-inch mesh.
Pea coal, which passes through .75-inch mesh, hut not through .50-inch mesh.
Buckwheat coal, which passes through .50-inch mesh, hut not through .25-inch mesh.
Very coarse lumps are known as "steamboat coal," and some finer sizes are at times separated into two kinds, which are known as rice and flax seed. The finest refuse from the breakers and mines is known as "culm," and has been a source of much concern since, through being considered as waste, it has been allowed to collect in enor mous helps, forming a marked topographic fea ture of the anthracite regions. Owing to the tine ness of this material, it was for sonic years found difficult to burn it in grates, as it packed and hin dered the entrance of air. In recent years meth ods of utilization for eulm have been found, and many of the banks have been worked over and the coarser particles washed out'and sized. It can he burned in specially constructed grates, or can be mixed with tar and pressed into briquettes for use with the ordinary grate. Another impor tant use is for filling in abandoned or partially worked-out mines, which is done by washing the culm down through a pipe into the mine, where it settles into a compact mass.
In the trade, anthracite is sometimes classed as follows: Free burning, white ash, hard white ash, Wyoming, red ash, Lehigh red ash, Shamokin. Lykens Valley red ash. Schuylkill red
ash, Trevorton, Lorberry red ash, and white ash. The hard white ash commands the best price.
The production of anthracite coal in Pennsyl vania from IS95 to 1900 was as follows: It is also of interest to note the increase in shipments since the beginning of the industry: The shipments in 1899 went to forty different States and Territories, while 1,707,796 long tons were exported.
The annual production of anthracite in Colo rado and New Mexico combined amounted to 98,404 short tons in 1900. Various estimates of the amounts of anthracite remaining in the Penn sylvania fields have been made, and all agree in the conclusion that the deposits will last at the present rate of production for more than one hundred years. For illustration, see COAL.
BIBLIOGRAPHY. For statistics of production, Bibliography. For statistics of production, consult volumes on Mineral Resources, issued an nually by the United States Geological Survey; various reports of the Second Geological Survey of Pennsylvania, and the Annual Reports of the Bureau of Mines, Pennsylvania. Consult also: J. J. Stevenson, "Origin of Pennsylvania Anthra cite," Bulletin of the Geological Society of Amer ica, Volume V., page 39 (Rochester, 1894) ; J. J. Stevenson, "The Cerrillos Coal Field," Transac tions of the New York Academy of Sciences, Vol ume XV., page 105 (New York, 1896) ; N. F. Drake, "Coal Fields Around Tse Chau, China,' Transactions of the American Institute of Min ing Engineers, Volume XXX. (New York, 1898) See also COAL, and PENNSYLVANIA.