Silvertip Pipeline Survey
Morrison-Maierle began working on this project on July 4, 2011, when the Silvertip pipeline broke in the Yellowstone River near Laurel, Montana. As a subcontractor to PSOMAS, a California company contracted to ExxonMobil Pipeline, Morrison-Maierle was on call to provide mapping and any other surveying services needed by ExxonMobil.
The ﬁrst task was to provide topographic mapping at the spill site so that a directional drilling could be engineered to get the pipeline back into production. Once ExxonMobil engineers were on site, Morrison-Maierle coordinated activities on a daily basis and provided topographic mapping of the proposed area and utility location of existing pipelines that might have been in conﬂict. All record documents were researched to determine if utilities had been located. Morrison-Maierle also provided engineering drawings of the horizontal directional drilling design oriented to the control system at the site.
Additionally, Morrison-Maierle provided a scour analysis of two of the crossings and aided consultants and subcontractors with mapping and drafting services. We also provided photo control for aerial mapping of the three crossings and a legal description and exhibits of the new alignment at all three river crossings. This task required research and surveying of existing property lines to develop construction-area easements and permanent easements for the location of the new pipeline’s crossing of the Yellowstone River, The Clarks Fork of the Yellowstone, and Rock Creek of the Yellowstone.
Once the pipeline was back in service, Morrison-Maierle assisted Global Diving and Salvage in the extraction of the broken pipe. Morrison-Maierle coordinated, on a daily basis, coordinates of various points on the pipeline, rovided upland topographic services and detailed pipeline measurements, and provided numerous drawings with the pipeline measurements as directed by ExxonMobil and the U.S. Department of Transportation.