Environmental Effects of Mining in the Anthracite Region: Problems and Possible Solutions
Kenneth M. Klemow, Ph.D.
The Mining Procedure and Its General Ecological Impacts
Vast areas of eastern Pennsylvania underlain by anthracite deposits were greatly influenced
by the extraction and processing of coal during the past 150 years. The US Department
of Agriculture lists approximately 51,000 acres (ca. 80 square miles) of soils as
being mine-impacted in Luzerne and Lackawanna counties alone. Information from the
Bureau of Abandoned Mineland Reclamation of the Department of Environmental Protection
places the extent of impact at 98,000 acres.
The successful removal of coal required that it be extracted from intervening layers of sandstone and shale. Historically, two methods were used to extract coal: underground mining and strip (surface) mining. Underground mining typically followed seams of coal downward, producing vertical shafts and horizontally arranged tunnels that often extended for miles. In contrast, strip mining involved the use of large shovels and draglines to physically remove the overburden, thus exposing the coal seams. Once removed, the raw coal was separated from energy-poor “culm” material having high concentrations of silica, iron, and sulfur.
Regardless of the extraction method, anthracite mining has had huge environmental effects that can be classified in several ways. First, one can distinguish between aboveground and belowground effects. Second, mining caused physical damage to the landscape, as well as impacts to the original flora and fauna. Finally, the environmental effects can also be classified by effects on terrestrial vs aquatic ecosystems, though in many instances the former contributes to the latter.
Because most of the activity was well below the surface, the actual removal of coal by underground mining did not have much environmental effect. As will be noted later, however, it did produce secondary effects, especially to water quality. In contrast, strip mining has had a profound impact on the local terrain because of the creation of huge depressions (stripping pits), nearly vertical highwalls, and high mounds of accumulated overburden material.
Whether removed by underground or strip mining, purifying the anthracite created additional impacts on the landscape. One type of impact involved the creation of mounds of coal waste in the form of culm banks (also called gob or bony). Such banks typically contain rock fragments often 0.5-2’ in diameter that are rich in carbon, iron, and sulfur. Some of the larger banks are 200’ high and occupy hundreds of acres.
Preparation of coal for market also involved washing, breaking, and sorting coal pieces of various sizes. That process resulted in the creation of small coal fragments, often less than 0.5” in diameter, having low commercial value. Those fine coal fragments were separated from the larger, more valuable pieces of coal by settling, creating deposits of “mine wash” that were allowed to develop in sedimentation basins. Mine wash was often removed from the basins and spread over adjoining areas. In other instances, mine wash particles were carried downstream as wash water was released from impoundments.
Thus, the mining process left a significant percentage of northeastern Pennsylvania covered by gaping pits, huge mounds of coarse material, and sterile deposits of mine wash. The mining process created profound disruptions to the natural ecosystems in which they occurred. As noted, the ecological effects have both terrestrial and aquatic components.