Natural γ-radiation: A steering guide in coal seams

Abstract The principle of the determination of roof coal thickness by the measurement of natural γ-radiation is described. The magnitude and uniformity of γ-activities were determined for the relevant strata and from these theoretical estimates of the γ-flux-coal thickness relationships are derived and compared with that found using an Intrinsically Safe γ-counting system on a number of coal faces. Parameters relevant to the performance of a steering sensor for coal cutting machines are discussed.