Locating abandoned mine shafts using a proton magnetometer

The location of abandoned mine shafts is very important, especially considering increasing urban development in old mining areas. Many old mine shafts are unstable and liable to collapse. The usual methods of finding these shafts, such as coring, are very slow. A study was made using a proton precession magnetometer, of the anomalies associated with some old shafts at Rothley Shield near Newcastle upon Tyne, England. Computer contouring was also carried out to develop the optimum field technique for shaft location using the magnetometer. Several shafts were then successfully located, but further work in an urban environment highlighted difficulties due to noise