Crandall Canyon Mine Collapse, Utah: Case Example

Barbare Tewksbury, Hamilton College

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Students evaluate whether pillar failure and collapse caused ground shaking or whether an earthquake caused pillar failure and mine collapse in the Crandall Canyon Mine collapse in 2007.

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Structural geology course for geo majors.

Skills and concepts that students must have mastered

Stress vs force, principal directions of stress, brittle fracture, extension fractures vs shear fractures, focal mechanisms.

How the activity is situated in the course

In some years, I have used this as part of a homework assignment and, in other years, as part of a take-home exam. It could also easily be used as a class/lab activity.


Content/concepts goals for this activity

The primary goal is for students to apply content and concepts that they have already learned, but they also learn about coal mining techniques, mechanisms of mine collapse, and the usefulness of structural geology concepts in another discipline.

Higher order thinking skills goals for this activity

Predict the orientation and nature of failure surfaces, analyze a focal mechanism, interpret cause of mine collapse and defend the interpretation with evidence.

Other skills goals for this activity

Description and Teaching Materials

Students read a description of the event plus background information on room-and-pillar mining. They predict the orientation and type of fractures that could result in pillar failure, and they use a focal mechanism for the Crandall Canyon event to evaluate whether an earthquake caused the collapse or the collapse caused ground shaking. The focal mechanism is unlike any that they have seen before because it is not a double-couple solution; all first motions are down.

Assignment for Crandall Canyon Mine Collapse case example (Microsoft Word 2007 (.docx) 564kB May9 12)

Teaching Notes and Tips


Students individually submit written analyses with argument and evidence.

References and Resources

Pechmann, James C., Arbasz, Walter J., Pankow, Relu Burlacu, and McCarter, Michael K., 2008, Seismological report on the 6 August 2007 Crandall Canyon Mine collapse in Utah: Seismological Research Letters, v. 79, no. 5, p. 620-636.

Seismic Moment Tensor Report for the 06 Aug 2007, M3.9 Seismic event in central Utah:

Map of the Crandall Canyon Mine:

Crandall Canyon Mine Collapse FAQs:

Earthquakes within 3 km of the Mine:

Crandall Canyon Mine collapse update:

Campoli, Alan A., Kertis, Carla A., and Goode, Claude, 1987, Coal mine bumps: five case studies in the eastern Unites States: USGS Information Circular 9149, 39 p.

Arabasz, W.J., Nava, S.J., McCarter, M.K., Pankow, K.L., Pechmann, J.C., Ake, J., and McGarr, A., 2005, Coal-mining seismicity and ground-shaking hazard: a case study in the Trail Mountain area, Emery County, Utah: Bulletin of the Seismological Society of America, v. 95, no,. 2, p. 18-30.