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Cashman Dredging Works to Deepen the New York/New Jersey Harbor

By MarEx 2012-11-19 15:17:00

The expansion of the Panama Canal is expected to be complete by 2014 allowing for larger ships to navigate through the channel. In a continuing effort to modernize the New York and New Jersey Harbors for Post-Panama size ships, Cashman Dredging and Marine Contracting Co., LLC is dredging the Arthur Kill Channel along Newark Bay in New Jersey. Cashman began dredging the channel in December 2010 and was later awarded an additional contract to continue deepening the Arthur Kill Channel in 2011. The two projects are a joint venture between Cashman Dredging & Marine Contracting Co., LLC. and DonJon Marine Co., Inc.

The projects are complex and are made up of several components. Much of the fine silts, clays and sand along the bottom of the channel are contaminated with mercury, lead, cadmium, PCB’s, dioxins or other substances and locating the appropriate disposal sites has been a challenge, however, the joint venture has succeeded in developing environmentally safe methods of transportation and disposal. Not only is a portion of the dredged material contaminated, but at the required depth of 52 feet below mean low water the required channel bottom extends ten feet into bedrock. To deepen the channel through the bedrock, Cashman is utilizing their drill boat, Kraken, to drill and blast in preparation to dredge to the required grade. All blasting and dredging operations have been strategically implemented without interruption to one of the nation’s busiest harbors. In order to maintain safety and efficiency during the project, Cashman is working closely with the USACE, Harbor Pilots, Port Authority of New York and New Jersey and the U.S Coast Guard.

At the start of the project, the blasted rock was used to create Shark River Reef off the coast of New Jersey as part of Cashman’s efforts for beneficial reuse. The blasted rock is now beneficially reused at the Historic Area Remediation Site (HARS) according to placement grids supplied by the USACE. The contaminated material unsuitable for HARS placement is treated during the offloading process before being transported to landfills. The material is mixed with cement at the onsite processing facility and is transformed from a pancake batter like consistency to usable soil acceptable for use as fill. The material is then transported and used for daily cover at the landfills. The project has been demanding and Cashman has successfully engineered complex solutions to overcome the many challenges that come with deepening the Arthur Kill Channel in Newark Bay, New Jersey. Once the deepening is complete, the New York and New Jersey harbor will be one of only two ports on the East Coast of the U.S. that will be able to accommodate the post panama sized container ships.

Drilling operations are performed 24 hours a day, 6 days a week, while blasting is performed Monday through Saturday between 9AM and 6PM. Blasting is not allowed on Sundays or Federal Holidays in order to comply with strict noise regulations put in place to minimize disturbance to surrounding residences. The projects are currently ahead of schedule and are expected to be complete by early 2013.