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Port Allen, La.
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Drax Biomass selected Gray for design and construction management services on the erection of two 120-foot-tall domes for wood pellet storage, conveyors and a shiploader at the Port of Greater Baton Rouge on the Mississippi River. This is Gray’s first project with Drax Biomass, a development and operating company focused on manufacturing wood pellets for renewable low-carbon power generation from sustainable biomass.

The domes are capable of storing approximately 80,000 metric tons of wood pellets, and will be loaded continuously by conveyors that collect pellets from the railroad and truck unloading buildings. Each dome has a 285-foot tunnel underneath that collects pellets once the domes are full and transfers them to the shiploader. The shiploader can load 1,200 metric tons of pellets per hour. Pellets are loaded onto the largest class of ship that is capable of passing through the Panama Canal in 3-5 days. The shiploader features luffing, shuttling, traveling and a telescopic chute.

Instead of piles or deep foundations, more than 15,000 yards of concrete were used for the dome ring beam alone. The domes are designed to settle into the ground up to 12” at the center and 8” along the perimeter. 

Project Facts

  • 17-month schedule
  • Building features:
    • (2) Domes constructed using TPO membrane, rebar and concrete; control room constructed using block and structural steel; and truck and rail unloading buildings constructed using PEMB
    • Floor constructed using 7.5” structural slab with 12” topping slab sloping to 16” to accommodate a reclaim screw
    • Wall constructed using block walls and brick veneer for control building, PEMB for truck and rail unloading buildings and shotcrete for domes
    • Tunnels
    • Material handling conveyors
    • Shiploader
    • Rail spur
  • This project included more than ¾ of a mile of conveyors, a 110,000-cubic-feet/minute aeration system in each dome and a total of 284,500-cubic-feet/minute dust collection system for all conveyors (110,000-cubic-feet/minute for each dome).


Services Provided by Gray:

  • Programming
  • Architecture
  • Civil Engineering
  • Permit Procurement
  • Electrical Engineering
  • Mechanical Engineering
  • Process Engineering
  • Structural Engineering
  • Wastewater Engineering
  • Construction Management
  • Design-Build
  • Equipment Procurement
  • Equipment Installation