It appears that spoils from the new Thimble Shoals tunnel may not be heading to Eastville. According to an article in Sunday’s Virginian Pilot, petroleum based foam and other additives that will enable the giant boring machine to remove the spoil from the bottom of the bay will in essence contaminate the material which will prevent it from being shipped to Eastville or deposited at a spoil site in the Atlantic Ocean. The additives known as TPH or Total Petroleum Hydrocarbons are measured in milligrams per kilogram of soil. EPA regulations kick in when TPH hits 50 or more milligrams.
Tests of samples of bay material combined with TPH samples showed 75 milligrams, which while not a major pollutant, does make it ineligible for disposal anywhere but in a landfill with a liner and a leachate removal system. The Eastville burrow pit site has neither. A proposed spoil site 17 miles offshore also cannot be used.
The additives are used to reduce friction, help the machine maintain proper pressure and turn the muck into a slurry that can be carried out by conveyor.
Bridge Tunnel Executive Director Jeff Holland said they knew there was always that potential. In an email to the Virginian Pilot Andres Gonzalez, a project executive with the builder said that “the test results and their ramifications have been expected from the beginning.”