top of page


MN Power provides regional power to a 26,000 square mile area in Northeastern Minnesota. The Thomson Hydro Plant is MN Power's largest hydroelectric system, capable of producing 120 megawatts of power. The scope of work for this project consisted of abrasive blasting and coating a 100-year-old riveted steel flow line and penstock system. Abrasive blasting of the steel surfaces was performed to a SSPC SP-10 Near-White Metal degree of cleanliness. Recoating consisted of applying a polyurethane lining on 200,000 sq feet of steel pipe surfaces. The flow lines had diameters of 11 and 12 feet and more than 8,000 lineal feet. Both penstock diameters were 7 feet with 800 lineal feet at a 45° angle. Confined space procedures were put in place to ensure all regulation and safety measures were met. All personnel were participated in mock rescue drills, confined space trained; while monitoring and PPE were provided. This project was part of the critical construction path during the plant's refurbishment outage. Challenges faced included the short construction schedule and the harsh conditions of a northern MN winter with temperatures down to -20°F. Daily field inspections of our work were completed in house and hold points were completed with the owner's 3rd party coatings consultant. The project was completed ahead of schedule and to the owner's satisfaction despite coming in after the original contractor was dismissed.

"I would like to take this opportunity to offer a sincere thanks for a job well done, the project was a challenging rehabilitation done throughout the winter to maintain our schedule. Your crew did an outstanding job in some very challenging situations. Throughout the project I felt that Hartman Walsh truly acted as a partner and this atmosphere resulted in a truly enjoyable project experience for everyone involved, a successful end result and a very pleased owner."


Tim Case, PM

Minnesota Power

bottom of page