Structural Geologic Interpretation

.A detailed model of the geologic structure inherent to the rock mass is required in order to conduct any design in rock. If a probabilistic design is to be conducted, the uncertainty of the parameters affecting design must also be addressed.

There are at least two "grades" of geologic structure.

• Rock fabric, or the small scale discontinuities that dissect the rock mass are of tremendous importance to local design in rock. These discontinuities, which often mimic larger scale structure orientations, can at this time generally only be addressed in a statistical fashion. This was one of the reasons for developing the program Z-Fabric. This program reduces mapping conducted in a pre-described manner such that the results can be incorporated in design models.;

• Major structure, or larger scale structures of whatever magnitude can be dealt with either as discrete entities or as populations. Intermediate faults, while belonging to the major structure catagory, can be dealt with in a statistical fashion ;

In either case, a complete structural model must be developed. This should utilize oriented drillcore, non-oriented drill core, field mapping, photogrammetry of major and minor structures, etc.

An interpretative technique for structural geologic models has been developed by Zostrich Geotechnical and is presently being taught to experienced mine geotechnical engineers and geologists around the world.