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Removing the tops of mountains is a coal mining method that is
widelypracticedintheAppalachianMountainsoftheUnitedStates.
Prior to the 1970’s coal in the area was only mined underground,
but now surface mining, that brings down mountains, makes it
profitable for companies to mine seams of coal that were once too
shallow or too thin to be viable (Bernhardt et al 2012). Generally,
between 150 and 250 meters of the mountain top is removed to
access the coal. It’s amethod that produces huge amounts of waste
– it is estimated that for every ton of coal 16 tons of overburden
(waste rock and soil) are removed (McQuaid 2009). This waste is
disposed in a controversial process known as valley fill. In 2012,
Bernhardt and Palmer (2012) estimated that valley filling had
buried over 2000 km of stream channels in the Appalachians.
But overburden is not the only waste produced at mountain top
mines. The coal is washed prior to shipment, to remove sulphur
and other impurities, including clay and rock, leaving behind a
contaminated slurry that contains known carcinogens (Epstein et
al 2011 and refs. therein). This slurry is stored in impoundments or
sometimes injected into abandoned underground mines. The more
common impoundments are generally constructed by building a
wall of coal waste across a valley to create a dam (OSMRE 2015). The
Appalachian region has many of these dams. InWest Virginia alone,
there are more than 120 containing over 100 billion gallons of coal
slurry (Epstein et al 2011). There are regular spills and leakages from
the impoundments – one of the largest occurred in 2000 when the
Massey Energy-owned sludge dam broke releasing more than 300
million gallons of slurry into undergroundmine shafts (Eades, 2000).
The sludge flowed from the mine openings, heavily contaminating
local creeks and rivers (Scott et al 2005). Studies have also confirmed
that leaking coal slurry from underground storage locations can
contaminate water supplies (Eckstein 2011).
Areviewoftheimpactsofmountain-topminingintheAppalachians
by Palmer at al (2010) reported reduced stream biodiversity and
water quality, including elevated pH, and increased concentrations
of metals including seleniumand increased sulphates below valley
fills. Increased surface runoff was also responsible for an increased
frequency and magnitude of downstream flooding. Studies by the
United States Geological Survey (USGS) also suggest that even
after mine remediation, domestic wells inmined areas have higher
levels of potentially toxic mine-derived chemical constituents than
well-water from unmined areas (McAuley and Kozar 2006).
In 2014 Appalachian coal companies started to file for bankruptcy
as the coal price fell due to the emergence of cheaper coal seam
gas. In 2015 one of the biggest coal companies in the world, Alpha
Natural Resources, the operator of dozens of mines in the region,
joined them(CBS 2015). Alpha has since emerged frombankruptcy,
but the failure of companies and continuing uncertainty in the
industry leaves the mountains of waste and the communities
living with them in an increasingly vulnerable position.
CASE STUDY
Mountain-top Coal Mining
The tophas beenblastedoff thismountain ridge in SouthWesternVirginiaanda large damconstructed to store sludgewaste.
Photo
©
OVEC/VivianStockman