A study from three Duke University researchers, published in early February in Environmental Science and Technology, attempts a landscape-scale accounting of the transformation of Appalachia. Using detailed satellite data for a 4,400 square-mile portion of southeastern West Virginia (a bit less than a quarter of the coalfield region and somewhat under 20 percent of West Virginia’s total area), they describe a terrain that has been broken and transformed. Active and abandoned mining sites occupied 10 percent of the region. In those sites, rubble filled valleys to depths of six hundred feet. Blasting and bulldozing had lowered ridges and mountaintops by as much as six hundred feet as well. A steep terrain with sharp contrasts between high ridges and low, stream-cut bottomland is becoming a muddled average of its original topography.

Where it has not been subjected to mountaintop removal, Appalachia is a region of slopes. There is precious little level ground aside from narrow ridgelines and narrower valleys (locally called hollows). In the 10 percent of the study area that has been mined, a terrain dominated by steep hillsides has been replaced by a mix of plateaus with remnant or reconstructed hillsides that are shorter and blunter than before mining. The most common pre-mining landform was a slope with a pitch of 28 degrees, about as steep as the upper segments of the cables of the Brooklyn Bridge. Today, the most common is a plain with a slope of 2 degrees, that is, level but uneven. Across the entire study region, mining has filled a steep landscape with pockets of nearly flat ground.

The researchers estimate conservatively that the volume of central Appalachian earth and rock turned from mountain to valley-fill is equal to the amount of ash and lava that spewed from the Philippines’ Mount Pinatubo in 1991, about 6.4 billion cubic meters. For comparison, that is 32 times the volume of material that the 1980 Mount Saint Helens eruption deposited in the northern Cascades. (In an email, Matthew Ross, the lead author on the study, speculated that a fuller accounting of overburden might double or triple the researchers’ estimate. He noted that 6.4 billion cubic meters would cover Manhattan in 240 feet of earth and rock.)

The region’s hydrology has been transformed. Because streams begin on mountainsides, and it is mountains that are being mined, this means that the region’s headwaters have been transformed. In place of mountains formed from layers of solid rock and coal, with a thin layer of dirt at the surface, there are now deep sinks full of compacted rubble, which works as a sponge. The researchers calculate that the valley fills can hold a year’s worth of rainfall, ten times more than the thin, clay-rich pre-mining soils.

As water lingers in the porous fills, it takes up chemicals from the shattered rock. It also absorbs alkalinity from carbonate stone that mining companies deliberately mix into overburden to prevent the disturbed stone from producing acidic runoff, which has turned many streams in mining regions bright orange and lifeless. In the study region, streams emerging from valley fills are as much as an order of magnitude more alkaline than neighboring streams, and also show high levels of toxic selenium. The streams are not dead, unlike those in acid-runoff watersheds, but the mining pollutants reduce fish and plant life well downstream of the valley fills.