Mining and minerals
Radioactive sources are used widely in the mining industry. For example, radioactive sources are used in non-destructive testing of pipeline blockages and welds; in measuring the density of material being drilled through; in testing the dynamic characteristics of blast furnaces, in the measurement of combustible volatile matter in coal, and for on-stream analysis of a wide range of minerals and fuels.
Mining companies use radionuclides to locate and quantify mineral deposits, to map geological contours using test wells and mine bores, and to determine the presence of hydrocarbons.
In milling and flotation operations, instruments using radioactive sources are widespread. These devices have the advantage of providing reliable non-contact measurement. Examples include the measurement of density and moisture in ore or slurries (important for process control and achieving final concentrate target moisture content). Other examples include measurement of levels in process tanks, slurry density and flows in piping, and levels in ore crushing chutes to detect blockages.
Various sources are used in such devices, for example americium-241 and caesium-137. Density measurement is based on the absorption of gamma radiation as it passes through process material. Absorption is proportional to changes in material density, and as the measuring path is held constant, this indicates density.