Understanding Salt Mine Ground Behavior through Geotechnical Monitoring and Data Analysis

Abstract

The Waste Isolation Pilot Plant (WIPP) was constructed for the permanent disposal of defense-generated transuranic waste from DOE sites around the United States. WIPP functions as a category 4 mine and category 2 nuclear facility. The waste is to be deposited 660 m (2150 ft) beneath the Earth’s surface inside of the Delaware Basin salt bed for permanent disposal. The first waste shipment arrived at WIPP in 1999 and is currently anticipated to operate beyond 2050. Due to the creeping nature of salt and the hazards involved in handling nuclear waste, it is paramount to monitor the changing conditions of the mine. Throughout the WIPP’s project life, geotechnical and mining engineers have developed and improved upon the data collection methods, instrumentation, and analysis that is required to monitor the ground movement in this unique salt mine. Using forecasting methods, WIPP’s geotechnical engineering team has predicted several ground falls and provides support to the site’s mining endeavors. A review of the historical ground movement data collection methods and analysis is given, as well as examples of ground falls and geotechnical abnormalities. In addition, ongoing application of operations research and engineering statistics will be discussed.