An electromagnetic mapping example for underground utility locating
During an underground utility survey, we were searching for a pipe which was supposed to be made of reinforced concrete. The pipe was about 4 feet in diameter and the depth to its top was about 7 to 8 feet. It's a big pipe, but unfortunately it's too deep to see it using our ground penetrating radar (GPR). After considering all the options, we decided to try electromagnetic (EM) mapping due to target and site characteristics. The survey area was a landfill area. As the picture shown above, despite extreme variations of local geology, the target pipe still showed up in the EM mapping, although partially/intermittently. Its closeness to a shallower metallic water pipe made the data interpretation more difficult.…
