PARTICLE-TRANSPORT IN GRAVITY CONCENTRATORS AND THE BAGNOLD EFFECT

The literature in a number of disciplines concerned with particle transport by water streams has been reviewed, from which it is clear that a better understanding of such transport exists than is reflected in the gravity concentration literature, which uses as a basis the 1939 analysis of Gaudin. The review highlights the importance of the work of Bagnold on particle-particle interactions in sheared flows, which has been widely cited in the gravity concentration literature. There appears however to have been no evaluation of the Bagnold flow regime for any gravity concentration device. The experimental evaluation of the flow regime on two different spirals represents a preliminary attempt at remedying this situation.