The difficulties of determining gold in rocks and ores are due to two causes: low gold concentrations in rocks (Clark 1 to
4·10
−7%), and non-uniform distribution of gold in ores. A method is proposed which is based on neutron activation of the lead alloy
obtained by cupel melting in the procedure of determining gold by cupel assay. Samples of 50 to 100 g are used for cupel melting.
Such large samples guarantee their representativeness. Discs of 2 to 3 g are cut from the lead alloy block and activated in
a neutron flux of 10
11 to 10
13 n·cm
−2 sec
−1. The gold content is determined from the photopeak of
198Au using a standard for comparison. The sensitivity of the method is 0.02 g/metric ton, its accuracy at a gold content in
the order of 1.0 g/metric ton is 10% relative. The method is distinguished by the fact that it is fast and requires little
labour.