SkyTruth, in partnership with Appalachian Voices, documented the impact of mountaintop removal mining for coal over a 59-county area in Kentucky, West Virginia, Tennessee and Virginia. The goal of the project was to map the direct landscape impact — the “footprint” — of mountaintop removal mining (MTR) over a 30-year period, from 1976 to 2005. The analysis was designed and conducted by our Chief Scientist, geologist and remote-sensing expert Dr. David Campagna.
With this analysis, and some great database and Google Earth work by Appalachian Voices, we can tell you exactly which mountains in Appalachia have been – or are are being -destroyed to power your home or business (thought you might like to know…). The methodology involved several steps. The first step included a land cover classification for each decade that identified all the mining occurrences at that point in time. This digital spectral classification process was accomplished using a Landsat satellite image database totaling eight gigabytes of data. Classification required a two-step process where the spectral signatures of land cover types were identified (vegetation, soil, barren or rock, water, etc) and then, through a decision tree analysis, mined areas are classed.
The next step was to classify these mine areas as “MTR” and “Other Surface Mining.” The definition of MTR, as put forth by the U.S. Office of Surface Mining, Reclamation and Enforcement, guided the development of a reproducible, rules-based method to classify the mines. Using digital elevation data from the U.S. Geological Survey 1:100,000 series, the terrain parameters of ridge top, slope, and valleys were calculated. MTR mines were identified by calculating the amount of ridge top that comprised the mine’s total area. Any continuous mined landscape that spanned over 320 acres and removed at least 40 acres of ridge top, or spanned between 40 – 320 acres and contained at least 10 – 40 acres of ridge top, was classified as MTR. Mined areas that were smaller than 40 acres, or did not meet these conditions, were classified as “Other Surface Mines.”
This analysis shows a 250% increase in the MTR footprint occurring in the last two decades, from 77,000 acres in 1985 to over 272,000 acres in 2005. The size of mining operations also increased, with some contiguous mined areas reaching over 15 square miles. Over 2,700 ridges were impacted by mining. Summary statistics are shown below:
Largest Contiguous Mined Area = 10,410 Acres
Median Mined Area = 128 Acres
Average Mined Area = 406 Acres
Number of Mines > 1 mile2 = 73
Average Ridge Length Mined = 1/2 Mile
Largest Ridge Removed = 504 Acres