page_title: Pittsburgh coal seam
section_title: Exploitation
hierarchical_section_title: Pittsburgh coal seam / Exploitation
caption_attribution_description: English: Original caption: "Figure 6, - Areas of the Pittsburgh coalbed that have been mined out." The legend originally incorporated into the figure named the mines: "1 Montour No. 4; 2 Mathies; 3 Maple Creek; 4 Westland; 5 Somerset No. 60; 6 Vesta No. 4; 7 Vesta No. 5; 8 Marianna No. 58; 9 Gateway; 10 Mather colleries; 11 Humphrey No. 7; 12 Shannopin; 13 Blacksville No. 2; 14 Blacksville No. 1; 15 Pursglove; 16 Osage No. 3; 17 Federal No. 2; 18 Arkwright; 19 Loveridge; 20 Federal No. 1; 21 Consol No. 93; 22 Consol No. 9; 23 Joanne; 24 Bethlehem No. 41; 25 Bethlehem No. 44; 26 Consol No. 20; 27 Robena; 28 Nemacolin; 29 Crucible; 30 Bethlehem No 51." The mined out areas have been colorized and the key relocated by the uploader, who claims no rights to these modifications.
context_page_description: The Pittsburgh Coal Seam is the thickest and most extensive coal bed in the Appalachian Basin; hence, it is the most economically important coal bed in the eastern United States. The Upper Pennsylvanian Pittsburgh coal bed of the Monongahela Group is extensive and continuous, extending over 11,000 mi² through 53 counties. It extends from Allegany County, Maryland to Belmont County, Ohio and from Allegheny County, Pennsylvania southwest to Putnam County, West Virginia.
  This coal seam is named for its outcrop high on the sheer north face of Mount Washington in Pittsburgh, Pennsylvania, and it is considered to form the base of the upper coal measures of the Allegheny Plateau, now known as the Monongahela Group. The first reference to the Pittsburgh coal bed, named by H.D. Rodgers of the First Geological Survey of Pennsylvania, was on a 1751 map.
  The section of the Pittsburgh seam under the Georges Creek Valley of Western Maryland is known as The Big Vein This is isolated from the rest of the Pittsburgh seam by Savage Mountain, the Negro Mountain anticline, the Laurel Hill anticline, and the Chestnut Ridge anticline.
context_section_description: In 1760, Captain Thomas Hutchins visited Fort Pitt and reported that there was a mine on Coal Hill, the original name given to Mount Washington across the Monongahela River from the fort.  The coal was extracted from drift mine entries into the Pittsburgh coal seam at outcrop along the hillside about 200 feet above the river.  The coal was poured into trenches dug into the hillside, rolled to the edge of the river, and transported by canoe and boats to the military garrison. Sometime around 1765, a fire broke out in this mine, which continued to burn for years, leading to collapse of part of the face of the hill.  Mining rights were formally purchased from the chiefs of the Six Nations in 1768, and from this point on, coal fueled the explosive growth of industry in the Pittsburgh Region.
  By 1796, coal mines extended along the face of Mount Washington for 300 fathoms (1800 feet), centered across the Monongahela from Wood Street.40°25′55.74″N 80°0′24.08″W  By 1814, there were at least 40 coal mines in the Pittsburgh region, worked from adits in the face of the coal seam using room and pillar methods. By 1830, the city of Pittsburgh consumed more than 400 tons per day of bituminous coal for domestic and light industrial use. In the early 19th century, Pittsburgh coal became the city's
  primary fuel source: about 250,000 bushels (approximately 400 short tons) of coal were consumed daily for domestic and light industrial use. The primary reason for the switch from wood to coal was one of economics. In 1809, a cord of wood cost $2.00 and a bushel of coal cost $0.06, delivered. The coal was plentiful and laborers, working in mines within a mile of Pittsburgh, earned about $1.60 per week and could produce as many as 100 bushels of coal daily.
  The Pittsburgh seam was America's principal seam of coal production during the late nineteenth and early twentieth century. Pittsburgh-seam coal was ideally suited to making coke, particularly for iron blast furnaces. It fostered the development of much of southwestern Pennsylvania, particularly a section of the Pittsburgh seam known as the Connellsville district.
  Exploitation of the Pittsburgh-seam coal began slowly. Initially, blacksmiths and foundrymen made coal into coke to use in their hearths and small furnaces. During the early nineteenth century, entrepreneurs in western Pennsylvania adapted British coke-making practices to produce coke for local iron works. To make coke, coal is burned under controlled conditions to drive off volatile matter (gases expelled when coal is burned), leaving carbon and ash from the coal fused together in the form of coke. They made coke in turf-covered "mounds," in which coal burned slowly and without oxygen to drive off impurities.  The adoption of beehive coke ovens in the 1830s spurred the use of Pittsburgh-seam coal in iron furnaces, and these ovens made better-quality coke than mounds.
  Pittsburgh-seam coal, especially the highest-quality coal found in the Connellsville district, was the best coal in America for making coke. When converted into coke, it was sufficiently strong to withstand the weight of iron ore that was piled with coke inside iron furnaces.  It has a high proportion of carbon, which accelerates  combustion, and a low proportion of impurities, including ash and moisture, which retards combustion. Pittsburgh coal also has a low proportion of sulfur, which is critical to making high-quality iron. In addition, the Pittsburgh seam was located close to Pittsburgh, then the center of the growing American iron and steel industry. Coke had to be transported by water or rail to iron furnaces, and the Pittsburgh seam's proximity to iron furnaces gave the bed another competitive advantage over more distant coal seams that could produce coke.
  The mining of Pittsburgh-seam coal boomed off after 1860 as the rapidly expanding iron and steel industry adopted coke. The output of the iron and steel industry burgeoned during the late nineteenth and early twentieth century as demand for steel products surged. To meet the corresponding demand for coke, P
caption: Mined out areas of the Pittsburgh Seam in Pennsylvania and West Virginia as of 1973.
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