Thickened Tailings Management, a Dynamic Process: Understanding and Optimizing the Thickener Operation

摘要

Thickened tailings management potentially has many benefits such as steeper beach slopes. Successful thickened tailings management, especially of the thickener operation and tailings pumping, may however bring many challenges since the process is more complex and thickened tailings are not as easy to manage as often expected. This paper reviews the experiences of thickened tailing management at two iron ore operations in Sweden; an ongoing production where the thickener was upgraded and a green-field site with design and tailings test-work based on pilot plant runs. Both operations have experienced difficulties in thickener operation and underflow pumping. As a result the beach slopes are lower than targeted. Extensive assessments were carried out on thickener operational data, results of rheological and physical tests, design data and how aspects not considered thoroughly enough in design, e.g. difference in yield stress characteristics, later has impacted the operation. The main reasons identified causing fluctuations in the thickener operation and underflow pumping were variations in feed, control parameters used and design of the underflow pumping. Following training of operators, partial re-design and revised thickener control parameters the performance of thickeners and yield stress of the tailing produced was improved.