Weak Rock Masses - Underground Design (North America
A major focus of ground control research presently being conducted by the Spokane Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) and the University of British Columbia (Geomechanics) is to incorporate data on weak rock masses into existing design relationships, with an emphasis on updating the span design curve for manned entries and the overbreak curve for longhole entries. Both curves were originally developed at the University of British Columbia, Vancouver, BC. The original database has been augmented by information from mines throughout the United States, Canada, Australia, Indonesia and Europe. The common factor in all these mines is the presence of a weak back and/or walls. In most cases, the ore zone is the weakest rock unit and must be stabilized so that the mineral-bearing rock can be extracted safety. The current joint research attempts to provide rock mechanics tools to assist a mine operator in making decisions that will ensure a safe and cost effective working environment. This paper documents North American underground operations that operate within a weak rock mass.
Stress, Rock mass, Structure