Dredging Works at LNG Terminal Off RGPPL, Dabhol.

Need

Revive the LNG terminal off Dabhol characterised by an Approach Channel of 8 Kms and a turning basin for Ratnagiri Gas and Power Pvt. LTD., (RGPPL).

Challenge

Removal of soft silts and soft rock (loose rock boulders, stiff clay, and weathered rock) so as to achieve a depth of 14.5m below CD. Dredging the Approach Channel, Turning Basin and near existing Jetty for removal of soft silt and soft rock to achieve the 14.5m depth below CD. Soft soil removal quantity is 5.15Million M3 and rock is 45,500M3.

Solution

DDIL deploys Trailing Suction Hopper Dredger (TSHD) “Josef Mobius” having hopper capacity of 5,500M3 and capable of dredging up to 25m, and a Grab Dredger “Pandora” having 20M3 bucket and 50T drop rock breaker (chisel shape) with 60m dredging capacity. TSHD to dredge in the soft soil areas and Grab Dredger to remove rock patches

Work Involves •Detailed hydrographic survey to ascertain actual sea bed and rock profiles in the dredging area using following equipments: •Single beam echosounder

• Multi beam echosounder
• Side Scan Sonar
• Shallow Seismic Profiles
• Removal of soft soil through TSHD and transported to offload at designated offshore disposal located 10NM form the dredging location.
• Surveys conducted regularly at disposal area to confirm dumping done as per specifications of Employer.
• Removal of rock embedded in the stiff clay using Grab Drdger and loaded in to the split bottom hopper barges. Tugs towed fully loaded hopper barges to the dumping location and offloaded at designated offshore dumping location. Rock boulders of bigger size (greater than 5 M3) also removed.

Result

DDIL completes project in compliance with high standards of safety.