SIROASH gauges for on-line determination of ash in coal

Two new coal ash gauges have been developed for direct use on coal carrying conveyors and for use on sample by-lines. One depends on the absorption of low energy gamma-rays, and the second on the production of gamma-ray pairs. The accuracy for both gauges is better than 0.5% by weight ash for low-ash coals, and, for the Pair Production gauge, better than 1% for high-ash coals