It would best be described as Applied Electrical Geophysics. In brief, measuring the flow and distortion of artificial electrical currents in the ground to figure out what is down there. In detail, I could have you excruciatingly bored and desperately looking for a way out in less than 5 minutes. The article you cite does not say much. Actually, nothing.
Look up Key Lake, MacArthur River, and Cigar Lake uranium mines, Lihir Island Gold, and Pebble Beach Copper. I did the initial geophysical mapping for all those, and others.