Anisotropy of magnetic susceptibility measurements as a coal banding-plane indicator

Abstract

MAGNETIC susceptibility measurements on coal were probably first made in Europe by Wooster and Wooster1 and mdre recently on American coals by Bivins and Ergun2. They suggested, based on orthogonal susceptibility measurements of coal cubes, that anthracite coals are anisotropic. But anisotropy of magnetic susceptibility (AMS), a second rank tensor3 which has been well documented4,5 has not previously been determined for anthracite and bituminous coals. We report here the results of AMS measurements which were carried out on some near-horizontal anthracite and bituminous coals collected in open cast and deep cast mines located in the South Wales Coal Field. The purpose of these analyses were threefold: to determine (1) if the results are internally consistent; (2) if such AMS measurements on coal are reliable; (3) if the AMS data can be used to solve coal-related geological problems.