U.S. Steel – Minntac Gallery Conveyor Rebuild

Project: Gallery Conveyor Rebuild

Owner: U.S. Steel Corp.

Scope of Work: Some portions of Minntac – Minnesota’s largest taconite plant – date back to the 1960s. This included their pellet loadout system, Conveyor 043/044, which loaded nearly half of the plant’s 15 million tons-per-year capacity and needed replacement. As a general contractor with significant experience in the mining industry, Lakehead acted in an advisory capacity to the project engineers regarding aspects of project construction.

To make way for the new conveyor system, a temporary load out was set up to ensure continuous plant operation. Sitework and foundations for the new structures began summer of 2022. This included three 60’ tall, 10′ diameter hollow mono-piers. Lakehead also constructed two conveyor galleries, one 350’ by 28’, the other 240’ by 19,’ to fully enclose the new conveyor system. The longer gallery was built to house two conveyors, while the second houses one.

Once the conveyors arrived on site, crews assembled internal components on the ground. The new fully enclosed conveyor galleries included 48” wide conveyors, forced air ductwork, pipe rack assemblies, fire protection, infrared heaters, electrical cable trays, washdown hoses, compressed air, and powered rooftop ventilation. The new conveyor was lifted to its 60’ position in six separate sections using two 300-ton Manitowoc crawler cranes in tandem. The total weight of all six sections was just over 1,000,000 pounds.

Safety: Lakehead Constructors completed 42,000 trade hours without incident; subcontractors safely completed another 28,000 hours.

Self-performed: Concrete, Steel Erection, High Pressure Piping and Welding, Plant Process Piping, Equipment Setting, Crane Support and Heavy Lifting, and Painting