Around Moretrench: Handling Coal Ash

May 11, 2015

Moretrench is well-known for its dewatering expertise in the civil construction marketplace.  What is not so well known, is that we have been applying that same expertise to the drainage and stabilization of gypsum, a by-product of the phosphate industry, for almost 40 years.  The storage of gypsum is markedly similar to that of another major industrial by-product – Coal Combustion Residual (primarily fly ash and bottom ash).   Both are transported and placed in slurry form, typically in large, above-ground impoundment areas.  And the dewatering methods that have proven so effective for the stabilization of gypsum apply equally effectively to CCRs.

Facility owners are actively working to comply with recent EPA-mandated guidelines on the construction and management  of CCR disposal sites,  and a properly engineered pre-drainage dewatering  program offers several distinct advantages.  For liner placement of active ash ponds, drawing down the groundwater allows stable, near vertical cuts to be made for mass excavation with conventional equipment.  When the intent is to cap the pond, dewatering provides a firm crust on the surface to support construction equipment so that the pond can be graded and the liner placed. Dry ash also occupies  a much smaller temporary storage footprint for liner projects.  Overall, dewatering allows for faster and safer  project completion.

Moretrench’s wide range of services means that we can also offer other critical remediation measures for CCR facilities such as dam and levee repair and rehabilitation, and cut-off and containment barriers to prevent the migration of contaminated soils.