Paste, or thickened tailings, have become an increasingly important method to address many of the environmental problems facing the mining industry. The term “paste” as used in this discussion applies to the full range of non-settling tailings that exhibit a yield stress such as “thickened tailings” and “mine paste backfill.”
Numerous studies and papers have been devoted to the subject of thickener design and operation to achieve specified throughput and discharge densities. Mathematical models have been developed that present methods for sizing thickeners and predicting performance under varying process conditions. The compression effect of deeper beds on dewatering performance is a recognized phenomenon. This is one variable of many that are inter-related and influence thickener performance. For example in the steady-state, continuous operation of a thickener, if the solids feed rate increases and the bed level remains the same, the underflow discharge rate must increase with the result of solids concentration being lower. The interactions of these parameters are at the heart of thickener models. Knowing the bed depth is critical to maintaining stable thickener operation.