Tailings impoundments - A growing environmental concern

摘要

Technological advances in recent years have meant that it is now possible to mine lower grade mineral deposits more economically. Developments in large mobile equipment and mineral processing techniques have played an important role in achieving this. However, these low grades result in large waste fractions that need to be stored by a method that meets environmental legislation that is becoming more stringent as decades go by. The most common method of storage is a surface impoundment which is raised as the volume of tailings requiring storage increases. Failures worldwide have sparked concerns over the design, construction and management of these impoundments. Many failures occur due to poor construction techniques and the management of the water within the impoundment. Liquefaction events, overtopping, and piping are all aided by the degree of saturation of the tailings and embankment materials. Reducing the water content should, in theory, reduce the risk of failure and this is one reason for the recent development of paste technology. This paper looks at the types of surface disposal methods currently available and past examples of particular failures.