Anthracite has been extensively mined in four areas of eastern Pennsylvania. Almost all underground mining in the four areas, the Northern, Eastern Middle, Western Middle, and Southern Fields, has been discontinued and many mines are abandoned and flooded. Precipitation on much of the 408 square miles of coal fields infiltrates to the underground mine complexes, and is discharged as mine drainage from tunnels, mine entrances, and boreholes.
Mine drainage was measured and sampled at 251 sites that had a total discharge of 918 cubic feet per second, a total sulfate load of 1,470 tons per day, and a total iron discharge of 79 tons per day. The largest sulfate yield was 5.4 tons per day per square mile from the Western Middle Field. The yields from the Northern, Eastern Middle, and Southern Fields were 4.6, 3.6, and 1.4 tons per day per square mile, respectively.
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USGS Numbered Series
Reconnaissance of mine drainage in the coal fields of eastern Pennsylvania