The operational fluctuations of tailings thickeners have the potential to cause significant impacts on the tailings transport system and the tailings deposition at a tailings storage facility (TSF). The statistical analysis of actual recorded data of underflow solids concentration and flowrate of different thickeners is presented in this paper. The collected data are from the operation of four different mines; one Zinc-lead, two Copper and one Gold mine. The variability in these two important parameters can be related to process fluctuations, design or construction defects including instrumentation and controls, the variability in mine orebody during the life of the project or operation of the thickener. The analysis of the data shows that the actual performance of the thickener can be significantly different from what is usually considered at the design stage. An example is presented to show the impacts of thickener performance variability on tailings transport system and thickened tailings beach slope quantitatively.

Tailings transport is an integrated element in any wet tailings storage facility (TSF). Tailings from the process plant are often thickened to a moderate or relatively high (but still pumpable) solids concentration, depending on several parameters mainly the TSF deposition requirements and strategies, process plant water security status and the dewatering technology utilised. This paper overviews the transportation of paste and thickened tailings and discusses various aspects and considerations in the hydraulic design of the system. Material characteristics, flow behaviour assessment (rheological behaviour measurement and interpretation) and the basis of design definition are discussed.The recent developments in environmental authorities' regulations associated with the tailings pipeline burst and leakage management are also reviewed in this paper. The tailings leakage and spillage to the environment is one the main concerns for any tailings hydraulic transportation system, therefore as part of the tailings pipeline design, the pipeline integrity failure (due to pipe wear, overpressure bursting etc.) should be thoroughly analysed to propose proper mitigation measures.The paper discusses a methodology to assess the potential tailings volume release to the environment in an event of the pipeline integrity failure which would be of interest to the operators and designers.

The flow of non-Newtonian materials through open channels has been little-studied compared to research on circular pipes. This paper presents a new Reynolds number to predict the flow of non-Newtonian thickened mining tailings slurries in open channels. Our aim is to model the frictional forces caused by a material's rheology in the laminar regime. The flow behaviour predictions by this and previous models are discussed and validated against previously published experimental data. It is shown that the newly-defined Reynolds number achieves an appropriate evaluation of the friction at the boundary and average velocities, when compared with the experimental data for Kaolin and Bentonite suspensions. The new model requires rheometer data to determine the fluid index (n à ). It is preferred, as with tube viscometry, to set up a lab-scale flume from which n à can be determined graphically or by numerical differentiation. Alternatively the fluid index can be obtained from conventional rotational viscometry results.

One of the key parameters in successful implementation of thickened tailings schemes for tailings management is the achievable tailings beach slope. Study of geomorphology and hydrodynamics of tailings beaches has shown that the achievable beach slope is directly proportional to tailings solids concentration (i.e. rheology) and inversely proportional to discharge flowrate.Splitting the total tailings flowrate from the process plant, into multiple spigots prior to discharge to a Tailings Storage Facility (TSF), will result in formation of a steeper beach profile which will increase the storage capacity. Additionally, uniform distribution and discharge of tailings into the TSF is a key element in filling the storage evenly and optimising the TSF effective storage capacity.Two different generic spigot arrangement systems are usually used in practice for flow splitting: Linear Discharge System (LDS) and Central Discharge System (CDS). The main components and pros and cons of each system are discussed and compared in this paper. Items covered include hydraulics, operational challenges and effectiveness in flow splitting, minimising flows merging on the beach to achieve a uniform deposition and steeper beach slope, and the overall costs of the tailings management system (including tailings transport, distribution system and embankment construction).There are many aspects to be considered, but overall it is concluded that in the cases for which that the comparison has been undertaken, the CDS is a more effective, easier to operate and a less costly design than the LDS.

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