The investigation of effect of particle size distribution on flow behavior of paste tailings.

Determining the rheological behaviors of the materials in paste technology is very important when transporting the paste. The flow properties of the paste material inside the pipe should be determined when pumping at long distances. In this study, the flow behavior of paste tailings, which consists of different pulp densities (pd), were studied to determine the effect of the particle size distribution of the tailings on surface paste disposal. In other words, the study examined the effect of the particle size distribution on the rheological behavior of the tailings. According to the study's results, tailings with a particle size smaller than 38 µm behaved like a paste up to 70% pd. However, it lost its paste properties when the pd value increased. In the original tailings sample (as-received), half of the particles were under 38 µm, the behavior of the paste materials was observed up to 80% pd. In addition, in order to be pumped the paste, it was determined that the amount of <38 µm tailings content in the material had to be 20%. Furthermore, the methods are presented in this study for control the effect of the change in particle size distribution on the pumpability of the paste material.

The effects of cement on some physical and chemical behavior for surface paste disposal method.

Environmental impacts resulting from conventional tailings disposal such as tailings dam accidents are a common problem for base metal mines around the world. In this context, laboratory-scale studies have been carried out on the Surface Paste Disposal (SPD) method, which is one of the alternative surface storage methods. In this study, three different SPD designs were tested; and volumetric water content, oxygen consumption, and matric suction sensors in first, fifth and 10th paste layers plus pH- electric conductivity (EC) values were all measured. Specifically, it was determined that the amount of oxygen in the environment required for the oxidation of sulfur minerals is reduced in the cemented layers in Design 3. In addition, the cement additive keeps the pH values of the seepage in an alkaline environment (over 7) so that it minimizes the risks of Acid Mine Drainage (AMD) and heavy metals mobilization at low pH values. Also, the EC values started a downward trend and ion dissolution decreased in designs with cemented layers. As a result, it was understood from the sensor measurements that the cemented layers act like a barrier.