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A Study of Coal Availability in the Saxonburg 7.5-minute Quadrangle, Butler County, Pennsylvania

出版	Pennsylvania Geological Survey, 2005
URL	http://books.google.com.hk/books?id=iIRFtAEACAAJ&hl=&source=gbs_api

註釋The Saxonburg 7.5-minute quadrangle in west-central Pennsylvania is underlain by middle Carboniferous rocks, which contain the Sharon to approximately Upper Bakerstown coal-bed sequence. Of this sequence, only the Upper Freeport, Lower Freeport, and Middle Kittanning coal beds have been mined to any extent during the last century, accounting for only about 2 percent of the original coal removed. The Saxonburg quadrangle is one of six quadrangles chosen for study in the bituminous coal fields of Pennsylvania, and was selected to help demonstrate how much coal on average remains available for extraction in a typical mature mining district. Results from the study indicate that of the approximately 570 million short tons of bituminous coal originally in the Saxonburg quadrangle, 11 million short tons has been mined out. An additional 373 million short tons of coal can be excluded due to resource restrictions, such as land-use and technological restraints to mining, leaving only about 187 million short tons, or 33 percent, of the original amount of coal available for mining.