Figure B

Preliminary plot of magnitude versus time (UTC) for 28 seismic events in the University of Utah earthquake catalog located within 3.0 km (1.9 miles) of the inferred location of the collapse in the Crandall Canyon mine. The plotted data are for the period May 1 through August 14, 2007. Further study will be required to test whether any tectonic earthquakes below mine level are included in the sample. Experience elsewhere suggests that most, if not all, of the events are probably shallow and mining-related.