Is Rhodamine a good tracer to predict coal transport in water?

A simple and low-cost experimental procedure to compare the mixing and transport of two substances in water is presented in this paper, aiming to investigate if rhodamine can predict the fate of coal transport in water. The procedure is based on acoustic Doppler techniques to characterize the flow and imaging techniques to measure the transport of substances discharged from an instantaneous point source near the free surface. To validate this procedure, several tests are carried out for rhodamine and two subsamples of coal (defined by a fine and coarse granulometry) in a flume under currents. The results show that the mixing of rhodamine resembles the finest fraction of coal that is transported as a suspended material, but fails to characterize the larger coal grains that experience sedimentation. The procedure here proposed can be expanded to characterize the mixing of substances in a body of water under other conditions, such as waves or wind driven currents.