Rainbow Dam Redevelopment Project – Great Falls, MT

PPL Montana needed to upgrade and expand its power generation capacity at its Rainbow facility on the Missouri River. Initial plans called for 400’ of 25’ diameter penstock to be fabricated and delivered in 10’ sections. Selway approached Walsh Construction with a plan to fabricate anddeliver the penstock in much larger, half-sections.

Selway also provided the field welders for the project, who were required to work in steep and confined conditions. Our innovative, field welding procedures were conducted using customized scissor lifts and self-propelled welding carriages with magnetic tracks. Selway’s coatings department sandblasted the interior and exterior surfaces to a 3-4 mils profile, and applied Carboline 2-part epoxy to 25 mils DFT. Our AISC Sophisticated Paint Endorsement allows us to apply complex protective coating systems, such as zincs, epoxies, urethanes, and multicoat systems.

  • Selway’s transportation fleet delivering penstock ‘half-sections’
  • Challenging conditions were no problem for the Selway field welders