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 and deposit them into a culm dump. The coal breaker is a forerunner of the modern coal preparation plant.
Coal tipples typically were used at bituminous coal mines, where removing impurities was important but sorting by size was only a secondary, minor concern. Coal breakers were always used at anthracite mines. While tipples were used around the world, coal breakers were used primarily in the United States in the state of Pennsylvania. At least one source claims that, in 1873, coal breaking plants were found only at anthracite mines in Pennsylvania.
Function
The first function of a coal breaker is to break coal into pieces and sort these pieces into categories of nearly uniform size, a process known as breaking. The second function of a coal breaker is to remove impurities, and then grade the coal on the basis of the percent of impurities 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 :- Steam – in size.
- Broken – in size.
- Egg – in size.
- Stove – in size.
- Chestnut – in size.
- Pea – in size. There were three subsets of "pea coal":
- * No. 1 Buckwheat – in size.
- * No. 2 Buckwheat – in size.
- * No. 3 Buckwheat – in size.
Pre-breaker treatment of coal
Coal breakers were located as close to the anthracite mine entrance as possible, so as to minimize the distance the coal had to travel before processing. Prior to entering the breaker, the coal would be crushed and sorted in a coal tipple and, if necessary and if water was available, washed. All coal was screened in the tipple as it came out of the mine so that steam-sized or smaller pieces could travel immediately to the coal washer and/or coal breaker. Chunks of coal which were too large were then crushed in the tipple until it passed through the screen.Raw coal often contains impurities such as slate, sulphur, ash, clay, or soil, which requires that it be cleaned before shipment to market. Mine workers sampled the coal as it came out of the mine to determine whether the level of impurity recommended washing. Slate, sulphur, and ash have a higher relative density than coal, and will sink in agitated water. Passing the coal through the tipple was an essential pre-treatment process for coal washing, however, because the impure coal must be of similar sized lumps for coal washing to work. If coal washing was conducted, coal might enter the breaker "wet". This meant the incline of the various belts and conveyors had to be lowered so that the coal did not slide on the belts or move too quickly down chutes. Where coal washing was used, the coal breaker was expanded to handle both "dry" and "wet" coal simultaneously.
History and technology
Prior to 1830, bituminous and anthracite coal received little processing. The individual miner would use a sledgehammer to break up large lumps of coal, then use a rake whose teeth were set two inches apart to collect the larger pieces of coal for transport to the surface. Smaller lumps of coal were considered nonmarketable and left in the mine. Beginning about 1830, surface processing of coal began. Lumps of coal were placed on plates of perforated cast iron and men known as "breakers" would hammer on the coal until it was in lumps small enough to fall through the holes. The coal fell into a second screen, where it was shaken and the smaller lumps sorted. This "broken and screened" coal was worth much more than lump coal.Although bituminous coal had been widely burned as fuel since ancient times, anthracite coal did not come into widespread use until the 1820s. Shortly after the start of the 19th century, experiments in the United States showed that if anthracite coal lumps were more uniform in size and air flowed more evenly around the fuel, anthracite would burn hotter, more cleanly, and for a longer period of time than bituminous coal. Jesse Fell was the first to successfully burn anthracite coal on an open air grate. His method and 'discovery' in Wilkes-Barre, PA in 1808 led to the widespread use of coal as the fuel source that helped to foster America's industrial revolution. Anthracite coal began to be widely used in Wales in 1813 and France by 1814, and throughout the eastern United States by 1828. Efforts were soon made to discover ways to process anthracite coal to achieve the desired uniformity.
The modern coal breaker can be traced to 1844. Joseph Battin, a supervisor at a coal gas manufacturing plant in Philadelphia, Pennsylvania, invented the first coal breaker—two cast iron rollers through which the coal was crushed before it rolled down a chute and then through an inclined cylindrical screen. The screen had a mesh which was fine toward the front and became progressively less so toward the end. Larger chunks of coal, falling inside the cylinder as it rotated, broke up and eventually passed through the screen. Impurities, which were heavier, tended to exit the breaker at the end of the screen. The sorted coal would then be collected in bins below the screen, and transported to market. A fellow Pennsylvanian, Gideon Bast, licensed the technology from Battin, and erected the first commercial coal breaker in Schuylkill County, Pennsylvania, on February 28, 1844. A number of coal processing machines—such as rollers, crushers, washers, and screens—were developed in Europe and later utilized in the United States. By 1866, the coal breaker in the United States had taken the form most recognized today, with multiple stories and numerous screening processes and mechanical sorting devices. The first steam-powered shaking screens were used in the U.S. 1890, and the first steam-powered coal washers installed in 1892.
Until about 1900, nearly all anthracite coal breakers were labor-intensive. The removal of impurities was done by hand, usually by boys between the ages of 8 and 12 years old known as breaker boys. The use of breaker boys began in the U.S. around 1866. The breaker boys would sit on wooden seats, perched over chutes and conveyor belts, picking slate and other impurities out of the coal. Breaker boys worked 10 hours a day for six days a week. The work was hazardous. Breaker boys were forced to work without gloves so that they could handle the slick coal better. The slate, however, was sharp, and boys would leave work with their fingers cut and bleeding. Many breaker boys lost fingers to the rapidly moving conveyor belts, while others, moving about the plant, had their feet, hands, arms, and legs amputated when they moved among the machinery and accidentally slipped under the belts or into the gears. Many died when they fell into the gears of the machinery, their bodies only retrieved at the end of the working day. Others were caught in the rush of coal, and crushed to death or smothered. The "dry" coal kicked up so much dust that the breaker boys sometimes wore lamps on their heads to see, and asthma and black lung disease were common.
Public outrage against the use of breaker boys was so widespread that in 1885 Pennsylvania enacted a law forbidding the employment of anyone under the age of 12 from working in a coal breaker. But the law was poorly enforced, and many employers and families forged birth certificates or other documents so children could work. Estimates of the number of breaker boys at work in the anthracite coal fields of Pennsylvania vary widely, and official statistics are considered by historians to undercount the numbers significantly. Estimates include 20,000 breaker boys working in the state in 1880, 18,000 working in 1900, 13,133 working in 1902, and 24,000 working in 1907. Technological innovations in the 1890s and 1900s such as mechanical and water separators designed to remove impurities from coal significantly reduced the need for breaker boys, but adoption of the new technology was slow. By the 1910s, the use of breaker boys was finally dropping because of improvements in technology, stricter child labor laws, and compulsory schooling laws. The practice of employing children in coal breakers largely ended by 1920 because of the efforts of the National Child Labor Committee, sociologist and photographer Lewis Hine, and the National Consumers League, who educated the public about the practice and succeeded in passing child labor laws.
The regulation of coal breakers came slowly in the United States. In the United Kingdom, the government enacted a law in the mid-19th century requiring that coal breakers be built away from mine entrances. But in the U.S., neither the federal government nor the states adopted regulation of coal breakers until after many lives had been lost. Two disasters prompted the adoption of legislation. The first occurred on September 6, 1869, when a small explosion at the Avondale mine in Plymouth, Pennsylvania, blew flames up the mine shaft. The wooden breaker built over the mine opening caught fire and collapsed, trapping and killing 110 workers in the mine below. No legislative or regulatory action was taken at that time. But in 1871, a fire destroyed the wooden breaker built over a mine opening in West Pittston, Pennsylvania, trapping and killing 24 miners. Despite a shift away from wooden construction of coal breakers and opposition from the coal industry, the state of Pennsylvania adopted a law in 1885 requiring that coal breakers be situated at least 200 feet from the opening of any mine.