Pittsburgh-based Consol Energy, the largest U.S. producer of coal from underground mines, will build an advanced wastewater treatment plant to treat wastewater from multiple mines in Appalachia as part of a settlement with the U.S. Dept. of Justice, the Environmental Protection Agency and the state of West Virginia. The federal complaint, filed concurrently with the settlement agreement, alleges that, in the past four years, Consol mines violated pollution discharge limits in their Clean Water Act permits hundreds of times. The settlement, announced on March 14, calls for Consol to pay a $5.5-million civil penalty for Clean Water Act violations at
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.