Did you know that TVA makes a weekly report to the EPA OSC?
(link...)
HIGHLIGHTS
• The ash stilling pond dredging was initiated and approximately 3,000 cubic yards removed.
• Held a briefing on the root cause analysis for the TDEC technical team on May 21st in Nashville.
• About 18,000 cubic yards of river ash was removed from the Emory River.
• Received EPA approval on 5 minor work plans; rail spur, rail car offloading, barge area offload, ash movement east of Dike 2, and movement of yellow dredge.
• Submitted draft safety and health plan and time critical removal action memorandum to EPA.
• Work progressing on schedule on the rail spur construction. Nearly 800 feet of rail and ties have been positioned for installation.

I haven't looked on the TDEC website for information on the "root cause analysis".
I don't see the plans for the rail spur posted, but TVA has a Swan Pond Rd. lane closure notice on their website.