Coal slurry consists of solid and liquid waste and is a by-product of the coal mining and preparation processes. It is a fine coal refuse and water. Mining generates enormous amounts of solid waste in the form of rocks and dirt. This refuse is used to dam the opening of a hollow between adjacent mountains.
After the dam is built, the void behind it is typically filled with millions of gallons of waste slurry from a coal preparation plant. This impounded liquid waste can sometimes total billions of gallons in a single facility (e.g. the largest coal slurry impound in the United States is located at Little Blue Run Lake which holds 20 billion gallons of coal ash and smokestack scrubber waste).
High-profile disasters associated with these slurry impoundments have called into question their safety. In February 1972, three dams holding a mixture of coal slurry and water in Logan County, West Virginia failed in succession: 130,000,000 US gallons (490,000 m3) of toxic water were released in the Buffalo Creek Flood. Out of a population of 5,000 people, 125 people were killed, 1,121 were injured, and over 4,000 were left homeless. The flood caused 50 million dollars in damages. Despite evidence of negligence, the Pittston Coal Company, which owned the compromised dam, called the event an "Act of God." In 2002, a 900-foot (270 m) high, 2,000-foot (610 m) long valley fill in Lyburn, West Virginia failed and slid into a sediment pond at the toe of the fill, generating a large wave of water and sediment that destroyed several cars and houses.
The term "coal slurry" is also for a mixture of crushed coal and water, created so that it can be transferred by pipeline or with specialised pumps such as a progressive cavity pump to pump the highly abrasive, corrosive and viscous coal slurry.
Coal slurry contains a large range of constituents, including dissolved minerals that have been leached or washed out of the coal and other rocks. In addition, the slurry contains chemicals added to facilitate the washing or water re-use processes. One of these chemicals is acrylamide. Other chemicals found in the slurry and sludge include the following:
- Benzyl alcohol
- Butyl benzyl phthalate
- Dibutyl phthalate
- Diethyl phthalate
- Dimethyl phthalate
- 4-Bromophenyl phenyl ether
- 4-Chlorophenyl phenyl ether
List of slurry disasters
- Buffalo Creek Flood
- Aberfan Disaster
- Martin County sludge spill
- Kingston Fossil Plant coal fly ash slurry spill
- Little Blue Run Lake
- Hopey, Don (3 April 2014). "Little Blue Run coal ash site to close sooner; Plant owner must contain pollution". Pittsburgh Post-Gazette. Retrieved 2 April 2015.
- "Environmental Justice Case Study: Buffalo Creek Disaster". Retrieved October 10, 2006.
- "Massey Valley Fill Disaster, Lyburn, WV". 2002-07-19. Retrieved April 3, 2005.
- Red Valve Company: Coal Slurry Pipeline
- "Reasons why you should choose the right pump for coal slurry.". 2012-07-18. Retrieved September 18, 2012.
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