Colbert Ash Stack Closure Complete

In closing and covering an ash stack at retired Colbert Fossil Plant, TVA creates not only safety but also scenery.

OCTOBER 21, 2016—TVA recently completed a $16 million project to close the dry ash stack at the now-retired Colbert Fossil Plant in Colbert County, Ala. Started in the summer of 2015, this 67-acre project involved the installation of over 2.8 million square feet of plastic liner, 255,000 tons of soil (enough to cover the site to a depth of 18 inches) and 2.7 million square feet of sod.

colbert aerial

“By following TVA project management procedures, the joint project team worked collectively within their disciplines by incorporating lessons learned and other closure experiences to complete the Stack 5 project under budget, ahead of schedule and with no safety instances,” says Kris Johnson, general manager, Civil Project Management.

When the decision was made to shut down the generating facility, the team recognized an opportunity to accelerate closure of Stack 5 by more than a year by shifting the last few months of ash placement to an adjacent Pond 4. Using lessons learned from a pond closure at Widows Creek, the team recommended eliminating a 6-inch topsoil layer and placing sod instead, which saved two months of construction time and more than $1 million.

A cloth layer above the plastic liner keeps rainwater off the stack.  This advanced, highly engineered cover system will be monitored by TVA for the next 30 years. Groundwater also will be monitored and results reported to the Alabama Department of Environmental Management.

The scenic quality of the area is much improved by the closure. Large herds of deer and flocks of wild turkeys, along with other wildlife, have already made this area their home.

How TVA Is Storing Its Ash

Want to know more about coal ash enclosures? Read this interview with John Kammeyer, TVA vice president of Civil Projects, to understand what coal ash really is, what technology is used in the handling of it, how TVA stores it and more technical detail about capping coal stacks. Click here to learn more. about coal ash storage.