Milton R. Young Station Unit 2 Chimney

In 2008, Minnkota Power Cooperative of Grand Forks, ND, began a three-year long project of environmental enhancements at its Milton R. Young Station near Center, ND. The enhancements are aimed at reducing sulfur dioxide emissions from the coalfired power plant. As part of the project, Minnkota constructed a new concrete foundation and chimney for the facility’s Unit 2 generator.

Minnkota partnered with engineering firm Burns & McDonnell, general contractor Maertens-Brenny Construction Company, and concrete supplier Knife River – North Dakota for the first phase of the project – a 140-foot-wide, 11-foot-thick foundation to support a new 550 foot tall emissions stack.

Knowing the foundation needed to be placed as a single-pour, all parties coordinated this large undertaking through several months of detailed planning. Knife River started producing concrete at 8:00 a.m. Friday, October 17, 2008, and Maertens- Brenny completed its last placement at 5:10 a.m. Saturday, October 18, 2008. In total, 6,426 cubic yards of concrete were batched from four ready-mix plants and delivered by a fleet of 30 ready-mix trucks. The foundation pour was completed with no injuries or accidents, no rejected loads and almost five hours ahead of schedule. To Knife River’s knowledge, this was the largest continuous pour ever staged in North Dakota.

Nearly 9 months later, general contractor Pullman Power began the process of slip-forming a new 550 foot tall chimney on top of the foundation. Again working with concrete supplier Knife River, Pullman Power provided its propriety mix design for the slip-form. The technical mix design included super plasticizer, accelerators and a concrete temperature range that had to be maintained for the duration of the pour to ensure the concrete would set as required.

Knife River produced concrete 24 hours per day, 6 days per week for 6 weeks for this project. The stack measures feet in diameter at the base and 50 feet at the top and took nearly 4,500 cubic yards of concrete to complete. With the concrete work complete, construction crews will continue their work of installing the environmental upgrades. Milton R. Young 2 emissions project is scheduled to be completed, tested and online by November 2010.