DOE 2000. - Waste Isolation Pilot Plant - U.S. Department of Energy

WIPP RH PSAR DOE/WIPP-03-3174 CHAPTER 4
Topics associated with the stability of the roof of the underground facility are the primary focus of the
Long-Term Ground Control Plan. 5 During the period of time that the underground has been active, a
variety of ground control issues have been encountered ranging from minor spalling to roof falls. Minor
spalling is small pieces of the back flaking off or falling. The ground control program consists of many
aspects which include continuous visual inspections of the underground openings, extensive geotechnical
monitoring, numerical modeling, analysis of rockbolt failures, implementation of ground control
procedures, and comprehensive in situ and laboratory testing and evaluation of ground control
components and systems.
Each year the Long-Term Ground Control Plan 5 is rolled forward one year. This revision takes into
account developments in both WIPP and industrial support practices and materials, and any changes in
WIPP life and operational requirements. WIPP ground control plans are living documents that keep
ground control practice at WIPP both current and responsive.
Ground Control Practice
A comprehensive ground control program for the entire underground facility is followed at WIPP to
ensure safe conditions, operational efficiency, reliability and confidence, and regulatory compliance for
personnel and equipment.
Qualified and experienced personnel in Geotechnical Engineering, Mine Engineering, and Underground
Operations are responsible for and committed to the success of this program. The elements of the
program are monitoring; initial and on-going evaluation; engineering design and specification; data
collection and analysis; implementation; and maintenance as necessary. These elements include the
following main activities.
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Monitoring: The geotechnical performance of the underground facility is regularly evaluated by the
Geotechnical Engineering section. This evaluation is focused on providing early detection of
conditions that could affect safety and operations, and to permit further engineering analysis of the
performance of WIPP excavations in salt. At present there are over 1,000 instruments installed
underground, and additional instruments are installed as conditions warrant. Daily and weekly visual
examinations are performed by Mine Operations staff.
Evaluation: Geotechnical and mining engineers perform a variety of rock mechanics analyses to
ensure that rock mass behavior is correctly understood and proper ground control measures are
instituted from the beginning.
Engineering Design and Specification: The ground support system is designed and specified to
ensure the safety of staff and to facilitate operations. Maintenance activities are specified in
performance standards and procedures so that ground conditions presenting a potential hazard are
safely rectified. Ground control problems are addressed on an individual basis so that the most
appropriate method of remediation is implemented. Geotechnical Engineering is constantly
improving ground support systems in order to provide the most effective and safe methods and
materials possible for the underground facility.
4.3-11 January 28, 2003