Specifications include, but are not limited to: Seattle City Light (SCL), Generation, Operations, and Engineering Division will conduct operations to clean and remove inorganic mineral deposits from the inside of a 5-mile long section of the Tolt 68-inch diameter steel penstock. The hydro-facility typically produces approximately 15-16 MW. The Tolt penstock provides approximately 40 million gallons of water a day. The penstock is approximately 5-miles long and descends approximately 1,000-ft. It is buried with centerline at least 6 ft underground for virtually the entire length. Vendor will provide expertise, labor and material to design and fabricate two pigs; and provide field technicians for guiding and monitoring the pigging process, in support of a safe, effective, efficient operation.