CASE STUDY #37: 50 Mile Pipeline

Client Needs: A client south of the Mason-Dixon Line needs to pinpoint a 50 mile pipeline in XY&Z dimensions.  It’s a 16 inch, ferrous pipe believed to be buried under about 3 feet of sand.  The water depth is 3-9 feet.

ASI’s Solution:
Aqua Survey would trailer a shallow draft survey vessel to a boat launch near the survey area. Using Hypack software on our Panasonic Toughbook for track and control, a vessel-mounted RTK-DGPS system for positioning, we would tow a single Geometric 882 Cesium Magnetometer towfish to locate the pipe and follow it for the needed 50 miles. If the area is known to have bridges or other metal structures, we would use a Gradiometer Magnetometer configuration of two magnetometers. This arrangement reduces the interference caused by metal structures. With processed data in hand, a water-jet-probe would then be used to accurately determine the pipe’s burial depth at key locations along the survey route.

What If:
What if the client wanted to locate a copper cable?  Can it be found with a Magnetometer?

What If Solution:
Magnetometers can only detect ferrous objects. Therefore it will not be able to find a copper cable. However, an Electromagnetic Induction (EMI) Metal Detector can identify and map both ferrous and nonferrous (e.g., copper) objects. EMI systems are commonly used to detect unexploded bombs and gold. Processed EMI data can be mapped and, if applicable, safely jet-probed to determine burial depth.