The geological recipe for making anthracite
Excerpted from http://www.MineCountry.com/homeMine/dispart.cfm?id=65 October 2003
Given the geology, the anthracite fields of Northeast Pennsylvania are not continuous, but are broken into fields. Thus, the anthracite region is divided into four distinct fields covering an area of about 490 square miles.
The Northern Field, with an area of about 176 square miles, extends through the Lackawanna-Wyoming Valley from Forest City to Shickshinny in a canoe-shaped arc. The coal beds lie in near horizontal layers, gently sloping up the sides of the valley where they are exposed in outcrops running along the flanks. The field is about 55 miles long and has a maximum width of about six miles. Vertical shafts in this field have depths ranging from a few hundred feet to almost 1500 feet at the deepest points in the southern end near Nanticoke. The principal towns in the field are Forrest City, Carbondale, Scranton, Pittston, Wilkes-Barre, Plymouth, Nanticoke and Shickshinny. Mining companies present here included the Hudson Coal Co., Lehigh Valley Coal Co., the Delaware, Lackawanna and Western Coal Mining Co., the Lehigh and Wilkes-Barre, Coal Co., the Pennsylvania Coal Co., and the Susquehanna Coal Co.
The Eastern Middle Field is located in the vicinity of Hazleton and is about 26 miles long and 10 miles wide. It is the smallest of the four fields and consists of a series of smaller, trough-like basins of coal beds running in an east to west direction. There are at least nine separate tracts in the field. Some of these basins lie near horizontal while others are severely folded. The principal city here is Hazleton with nearby smaller villages including West Hazleton, Harleigh, Eckley and Audenried. The majority of collieries in this area were the smaller family owned operators such as Coxe Brothers and Co., Pardee Brothers and Co. and the later Jeddo-Highland Coal Co.
The Western Middle Field runs in an east and west direction for about 33 miles passing through communities such as Mahanoy City, Shenandoah, Ashland, Centralia, Mount Carmel and Shamokin. At its maximum, the field is about four miles wide. The geology here consists of many small parallel valleys and ridges and severely folded and faulted coal seams. Deep shafts went down as far as 1500 feet in this region. The Mammoth Coal Bed is most prominent here reaching a maximum thickness of greater than 30 feet. The Philadelphia and Reading Coal and Iron Company and the Susquehanna Coal Co. were the most prominent operators in the region.
The Southern Field is the largest of the four anthracite fields consisting of several smaller, interconnected coal basins. The main axis of the field extends for approximately 55 miles in a southwesterly direction beginning near Jim Thorpe (Mauch Chunk), and ending into two tails in Dauphin County. The major towns contained in this field include Lansford, Coaldale, Tamaqua, Pottsville, Minersville, Tower City and Lykens. The coal beds here are severely folded with the deepest layers reaching down to 2000 feet. The dominant coal operator here was the Philadelphia and Reading Coal and Iron Co.
At least 40 coal seams are within the four fields and there are several smaller, erratic fields in between. These range in size from a few inches in thickness to many feet. Most are named, but not all of them are workable due to their thinness or economic value. Their names are almost site-specific and can be different between fields and even between coal companies.
The thickest layer is the Mammoth Bed, most prominent in the lower Southern Field and Western Field where it reaches a thickness of 40-50 feet. It is most commonly called the Baltimore Bed, among other names in the Northern Field, where it has a thickness of several feet. The deepest beds are the multiple splits of the Red Ash Bed in the Northern Field. It is know as the Buck Mountain Bed in the Eastern Field and the Lykens Bed in the Western and Southern fields. The Southern Field has the most extensive layering of the four fields.
Darton, N. H. Some Structural Features of the Northern Anthracite Coal Basin, Pennsylvania. Washington: United States Government Printing Office, 1940.
Griffith, W. M. Approximate Columnar Sections Showing the Co-Relations of Anthracite Coal Beds of Pennsylvania. Scranton: W. M. Griffith, Mining Engineer and Geologist.
Haine. Edgar A. Anthracite Coal. Chicago: Adams Press, 1987.
Hudson Coal Company. The Story of Anthracite. Scranton: International Textbook Press, 1932.
Levin, Harold L. The Earth Through Time. New York, NY: Harcourt Brace Publishers, 1999.
Levine, Jeffrey R. and Jane R. Eggleston.The Anthracite Basins of Eastern Pennsylvania. Pennsylvania State University, 1992.
Majumdar, Shyamal K. and E. Willard Miller.Pennsylvania Coal. The Pennsylvania Academy of Science, 1983.
Revised December 2009