National Grid To Resume MGP Site Work
National Grid announced this week that they will resume work at the former manufactured gas plant at Beach 108 Street where they will install a 120- foot barrier wall on the Beach Channel Drive side of the site.
Work had been suspended on the site earlier this year when the project manager needed to find an alternate way to drop the barrier wall down to 120 feet. National Grid stated that at the 60-foot mark, compacted soil and minerals made the drilling method they were using ineffective.
Excavation of the site, which included removing eight feet of contaminated soil, is complete and the area has been backfilled with sand and gravel. The barrier is designed to prevent deep MGP tar from migrating off the site towards Jamaica Bay and is one of the last obstacles to the project’s completion.
The project which started in September 2008, was supposed to be finished by September 2010. However, delays in the barrier wall have pushed back the completion date several times. According to National Grid, they will mobilize onto the site this month and starting in early winter they will utilize jet grout technology to finish the wall. The jet grout will be injected under and attached to the existing 60-foot deep sheet pile barrier that was installed in 2010.
National Grid representatives say they will repair the excavation tent as well in the upcoming weeks and use it for day-to-day operations while they install the barrier wall.
“The next few months will be spent building the on-site facility to produce the grout (a form of concrete), making other preparations for the work and evaluating processes to ensure a firm attachment of the grout to the existing sheet pile and forming a solid wall down to the required 120 foot depth, an official said.
Actual installation of the wall will begin in early winter and run through Spring 2012,” National Grid spokesperson Karen Young said this week.