Lessons Learned from the 20-Year Assessment/Renewal of the Homestake Transmission Pipeline

In 2005, a fast-track repair was required for the failed Homestake Pipeline within the 6,000-ft long Goddard Tunnel passing under the continental divide in western Colorado. This episode led to a 20-year program of assessment, repair, renewal, and replacement. This process has included a 5-year phased condition assessment on the Homestake Pipeline, a 20-year capital improvement plan to extend the service life of this critical facility, adoption of an evolving series of assessment technologies, and implementation of 15 years of renewal projects utilizing four construction methodologies. This comprehensive program has revealed several insights for those undertaking condition assessments and utilizing numerous emerging technologies while actively implementing a long-term renewal program. Among those are the benefit of objective research into the capabilities, limitations, and efficacy of technology tools and strategic use of those tools as part of an overall assessment approach coupled with the importance of independent verification of results from high-technology tools. As a cohesive team, we utilized advanced planning to estimate the cost and operational impacts of shutdowns or facility modifications required to perform the assessment and renewal work. This approach allowed the team to adopt a phased the program with subsequent steps based on results of previous work to improve outcomes and manage costs effectively. Early in the program, the team identified the benefits of holding a formal “lessons-learned” workshop at the completion of each year of assessment and rehabilitation and utilized this process to assist in managing and evolving a long-term renewal program to reprioritize for critical developments, on-board evolving technologies, and stay within budgeting and operational constraints. The continuation of the next 20-year phase of renewal is set to begin in 2025.