Abstract: Researchers at the U.S. Bureau of Mines have developed personal-computer-based data acquisition, instrumentation, and mine visualization and modeling techniques to evaluate a mine accessway in a deep hard-rock mine in northern Idaho. These techniques were applied to a mine shaft in a large silver mine that has been in operation for many years. A very deep, rectangular, timber-supported shaft extending to depths exceeding 2.3 km (7,500 ft) had been deforming continuously as a result of nearby mining, resulting in operational problems. Preliminary visual observations and rock and support monitoring confirmed that severe diagonal distortion was occurring. Extensive field measurements and data analysis confirmed initial observations, provided insights into the cause of deformation, and defined a general approach to structural modeling. Computer analysis of the problem was initiated by developing a three-dimensional model of the terrain. This represented a volume of rock approximately 80 km3 (40 x 1010 ft) and an area on the surface surrounding the mine 9 km2 (3 square miles). Based on this model, a three-dimensional, finiteelement analysis was conducted to establish boundary conditions for sequentially more detailed two- and three-dimensional submodels of the shaft area. Results from the computer study are being used to develop new …

The following report presents detailed lethologic and conodont biostratigraphic data from four measured sections in the lower part of the Oquirrh Group in the Oquirrh Mountains of Utah and the Deep Creek and Samaria Mountains of Idaho.

The following report presents measured sections and lithostratigraphic correlations of the units in the order to document a syntectonic unconformity in order to understand the tectonic history of the area.

Report containing a series of chapters discussing the geologic and mineral resources of the Hailey Quadrangle and Western part of the Idaho Falls Quadrangle in Idaho.