Drilling rigs are taking core samples. Hard Amphibolite (blue grey color) is observed in the center of the longer core sample under inspection. If you have a good zoom on the image you can see black "line" markings placed on the rock to measure angles of the fractures (note drafting tools). The whiteboard denotes "Oroville Spillway Emergency". However, the drilling location may only be roughly inferred from electrical power lines in another image. Core sampling of the subsurface rock is data that would be important for any "next step" phases or proposed options for a new spillway replacement and/or repairs.
Core Sample Analysis - A hard Amphibolite rock seam (blue grey color) observable in the middle of the longer core sample being inspected.
