Royal Concrete Pipe

Located in Sauk Rapids, Minn., Knife River Corporation is a subsidiary of the MDU Resources Group. It is a fully integrated, independently managed and operated construction materials and mining company. It uses large equipment, crushers, conveyors and loading equipment for mining and related construction materials production. It mines aggregates and markets crushed stone, sand, gravel and related construction materials, including ready-mixed concrete, cement, asphalt and other value-added products, as well as performing integrated construction services. It also manufactures and distributes liquid asphalt cement, as well as recycles used petroleum products. It provides materials and services to both the public and the private sectors. It has operations in nearly 10 states, including Alaska, California, Hawaii, Iowa, Idaho, Minnesota, Montana, Nebraska and Oregon.