Undisclosed Surface Mine in North America


This open-pit mine is located in the western region of the United States.  For scale, each mine bench face is 50 feet high and the failure occurred at about 2:00 AM.  This image from GoogleEarth was taken in 2013, and the once near-verticle head scarp now contains overcast material from mining and sloughing.  At the present time, the head scarp and failure debris have been mined out.  

Inverse Velocity Data Prior to Failure

Inverse velocity time series data of the mine pit instability before failure.  Data was being acquired every 4-minutes 24/7.  The important observation from this figure; is the data's approach towards linearity, which means that most of the entire slope surface has begun to accelerate at nearly the same rate increasing confidence that a failure will occur at the intersection of the best fit trend line (dashed black line) to the x-axis.  For this particular instability, thousands of radar DTM cells (similar in concept to pixels) are being resolved to determine slope movement rates and then averaged with the result shown as the blue curve.  Astoundingly, the scanning, processing, and the transmission of data to computers with no end-user processing occurred every 4-minutes 24/7.  The latest radar units complete this same operation every 2-minutes 24/7 in all weather conditions.

The decision to block and restrict access to this corner of the mine was made on November 3, 2012, as a result of the visual approach to data linearity, regression analyses showing a progressive increase in confidence and the time of failure predicted by the best-fit trend line.

Undisclosed Surface Mine in North America


This image was taken at about 11:00 am on November 6, the day of the failure.  Much of the dust generated by the failure remained in the pit, blocking a clear view of the failure until a slight late morning breeze began.  Some of the lingering dust can be seen in the lower right portion of the image