Coal Slurry Impoundments - Policy Recommendations

Many environmentalists recognize that coal is the dirtiest means of producing electricity, especially with regard to greenhouse gas emissions and other issues related to air quality.
Many also have grave concerns about the increasingly destructive methods employed for extracting coal. In comparison to the utter devastation that comes with Mountaintop Removal (MTR), traditional underground mining, with its acid mine drainage, subsidence, and occasional methane explosions, seems almost benign in comparison.

A significant, but often hidden impact of coal mining (regardless of the method of extraction) is the process of coal “washing” which produces enormous quantities of a toxic soup called coal slurry. Current practices regarding coal slurry production and storage are not sufficient to protect human health,

property, and the environment and should be significantly strengthened with a combination of more stringent standards and enforcement along with market-based incentives to encourage existing and emerging “best practices”
for the safer production, storage, and disposal of coal slurry. Specific recommendations include: full enforcement of existing laws related to coal slurry impoundments, a moratorium on the injection of coal slurry into underground mine workings, greater oversight of the engineering, construction, and maintenance of all slurry impoundments, implementation of alternative “coal washing” processes

that do not produce so much wastewater, and alternative disposal techniques which rely on “dewatering” the slurry itself, dramatically reducing the volume of liquid in any one impoundment.

Before a case can be made for these recommendations, a little background information is needed. Around a hundred years ago, it was discovered that an easier way to separate coal from rocky debris was to “wash” it. Because coal tends to float in water, it made the separation process a lot easier, which had previously been done by hand, usually by child laborers called “breaker boys”, seen working in the picture on the right.

This traditional “wet method” of coal separation produced significant quantities of wastewater, which contained some of the heavy metals and hydrocarbons from the coal itself. Over the last century, this wet method has “advanced” a great deal - chemicals are now added to enhance the separation process including hydrophobic compounds such as diesel fuel which help float the coal to top of the separation tank and hydrophilic compounds like highly toxic acrylamides which cause non-coal particulates to settle to the bottom. A simplified schematic (shown below) shows how this process works today.

The wastewater produced from this process contains 53 known substances (other than water) – some of which are leached from the unwashed coal, some of which are added to enhance the washing process. Here are just a few of them along with their known health impacts: acrylamide (linked to female reproductive cancers, damage to male reproductive glands, a neurotoxin), anthracine (a persistent, bioaccumlative toxin, benzidine (linked to bladder and pancreatic cancer), chrysene (a suspected human carcinogen), and dibutyl phthalate (linked to obesity and insulin resistance, suspected in causing birth defects, a hormone disruptor).

Coal operators have two basic impoundment choices for storing the slurry: 1) they can utilize the existing topography along with mine waste to create an impoundment dam. 2) they can inject the slurry underground into abandoned mine workings. History has shown us that both types of coal slurry impoundments come with significant risks. The picture below shows a mass funeral in Aberfan, Wales after an above ground coal slurry impoundment broke in 1966, engulfing the neighborhood school. 144 people were killed, 116 of them children.

In addition to catastrophic failure events (Buffalo Creek 1972, Aberfan Wales 1966, Martin Co., KY 2000), smaller breaches and seepage into the water table plague many communities in the coal fields,

producing general contamination and occasional “black water” events.

All of these events, small and large, impact ground and surface water and are accompanied by significant health impacts for those who live in the area, with lower life expectancies correlated to proximity to coal operations which may be attributed, in part, to the water impacts of slurry impoundments.

This map shows the distribution of slurry impoundments in West Virginia as well as corresponding complaints about black water events in well or surface waters which shows a pretty clear connection between the concentration of slurry impoundments and the number of blackwater complaints nearby. Although these data seem compelling, it is difficult to understand the impact these events can have on families living in the shadow of a slurry impoundment. This short New York Times video journalism piece details the economic, health, and psychological consequences for one family. I strongly urge you to take 3 minutes and watch this moving piece.

Coal companies repeatedly cut corners on every aspect related to creation and storage of coal slurry, from selecting the method of coal washing, to pursuing the cheapest engineering and construction standards for slurry impoundments, to failing to properly maintain and monitor existing impoundments, to abdicating financial and ethical responsibility when failures occur. Very often, coal companies flagrantly violate even the meager existing laws regarding coal slurry impoundments, knowing the financial repercussions will be minimal, if history is any guide.

I assert that existing laws, if properly enforced would do much to address the risk of catastrophic failures of slurry impoundments. In some cases, however, existing policy allows certain practices, such as the underground injection of slurry into abandoned mine workings that many geologists and hydrologists recommend be halted until further study can determine its safety. Furthermore, existing and emerging technologies could mitigate some of the worst impacts of coal slurry impoundments, but political will must be exerted to create meaningful incentives for the coal industry to adopt them. It is clear that the command and control approach (alone) has only been marginally effective in protecting human health and the environment. Obviously the transition to a renewable energy system will take decades. In the meantime, the impact of coal slurry impoundments must be more meaningfully addressed.