Three typical coal fields of the Shahroud, Zirab and Lushan from the well-known geological setting of Alborz coal basin in north of Iran, chosen to cover a range of rank, were used to compare and contrast conventional ash measurement method to improving the newly made dual-energy gamma-ray device in Iran. The conventional method is based on the measurement of the ash percent by analytical balance. The dual-energy gamma-ray device method is based on the dual-energy gamma-ray transmission isotopes of Am-241 and Cs-137. Conventional methods (combustion method) for the measurement of coal ash are time consuming. Nuclear (isotopic) devices are a new technique that provides rapid and sensitive coal ash measurement of various coal types. We investigated the use of this technique (dual-energy gamma ray) for control of coal quality in Iran. The applications of conventional and nuclear devices for coal ash measurements in different coal types of the Shahroud mine show that the use of the nuclear technique is advantageous. (C) 2003 Published by Elsevier B.V.