ROCK ABRASION IN AUTOGENOUS MILLING

Waste rock from a South African gold mine was tumbled in a 600mm diame ter mill. Factors influencing the rate of abrasion of the rock and the product size were examined, including rock mass, pulp hold-up, distri bution of rock sizes, mill speed and lifter configuration. Tests were conducted on pebbles which had been rounded in the mill. It was demons trated that abrasion rate per unit mass increases significantly with r ock mass. A simple laboratory test for rock 'hardness' was shown to be correlated to the rate of abrasion. The rate of production of finishe d product from the coarse rock compares well with conventional grindin g under certain conditions. The implications of the findings for circu it design and control are discussed. (C) 1997 Elsevier Science Ltd.