The Frank slide: a reexamination of the failure mechanism

The Frank slide, involving an estimated 30 million m(3) of rock occurred in 1903 on the east face of Turtle Mountain, southwestern Alberta, Canada. It resulted in the loss of approximately 70 lives. Numerous authors have discussed the mechanism of the slide, with both limit equilibrium and elastic finite element analyses being conducted. This paper represents the first published account of the application of elasto-plastic finite difference and distinct element techniques to the Frank slide. It constitutes an attempt to improve our understanding of the ground deformation processes involved. The results of an extensive elasto-plastic modelling study illustrate that although the prime cause of the slide was the adverse geological structure, mining at the base of Turtle mountain could have acted as a final triggering mechanism. This appears to be in agreement with accounts published at the time of the disaster.