From February 12 to March 8, 1981, EG and G Geometrics conducted an aeromagnetic survey in Montana for Anaconda Copper Company. A Piper Navajo aircraft was used to conducted the survey. The survey was flown along north-south flightlines spaced 660 feet at a nominal height of 450 feet above the terrain. Five uniformly spaced east-west tie-lines were also flown. During processing, the International