7/3/2013
This is the wall running along the NW edge of the operation. The visibility of this wall above the surface partly determined the extent of the operation.
Top elevations (from WSDA1 datum 1):
N corner: 2138.131
center: -61.9 cm
W corner: -29.1 cm
Its lowest elevation, measured in the center, is 2137.07 mASL.