The source for the DPM-1 electromagnetic exploration method is a long, grounded wire (5000 to 25,000 ft in length). The transmitter operates at a frequency of approximately 500 hz and has a power output of 20 watts. The dip-angle is measured in a plane perpendicular to the wire at distances up to 12,000 ft from the wire.
A conductor is characterized by a marked flexure in the dip-angle curve, with the conductor axis lying approximately beneath the inflection point of the curve. Case histories from the Manitoba nickel belt and the Uchi Lake mine, Ontario show good responses for conductors from near surface to 150 ft depth.