This article constitutes an analysis of the feasibility of the application of the so popular presently idea of the circular economy in the area of mining waste management. It describes the specificity of the mining waste generated during the mining and the enrichment of copper ore, i.e. waste rock (gangue), tailings. That specificity results first of all from the character of the processes where the waste are generated and the amount of them. The waste properties are described, the implemented methods of handling it are presented, as well as the prospective technologies of recovery developed in the range of research works. The presented examples show that the implemented methods of waste rock recovery can be an illustration and model of the functioning of the circular economy (or in other words for this case wasteless economy). However, as it comes to the flotation tailings the fact has been emphasised that the research studies are being carried out for decades aimed to search a possibility to recover as much waste as possible. Those deliberations lead to the conclusion that at present in reality the only method of that waste management is to deposit it in an environmentally safe way.
The increasing challenges related to the reliability and durability of steel pipeline infrastructure necessitate a detailed understanding of degradation and failure mechanisms. This study focuses on selective corrosion and erosion as critical factors, analyzing their impact on pipeline integrity using advanced methods, including macroscopic analysis, corrosion testing, microscopic examination, tensile strength testing, and finite element method (FEM) modeling. Selective corrosion in the heat-affected zones (HAZs) of longitudinal welds was identified as the dominant degradation mechanism, with pit depths reaching up to 6 mm, leading to tensile strength reductions of 30%. FEM analysis showed that material loss exceeding 8 mm in weld areas under standard operating pressure (16 bar) induces critical stress levels, risking pipeline failure. Erosion was found to exacerbate selective corrosion, accelerating degradation in high-stress zones. Practical recommendations include the use of corrosion-resistant materials, such as duplex steels, and implementing integrated monitoring strategies combining non-destructive testing with FEM-based predictive modeling. These insights contribute to developing robust preventive measures to ensure the safety and longevity of pipeline infrastructure.
The safe operation of the large, outflow Tailings Storage Facilities (TSF) requires comprehensive and continuous threat monitoring. One of the basic kinds of threat monitoring is to monitor the water conditions in deposited tailings, which is usually carried out using a conventional piezometric observation method from a network of installed piezometers. In complex tailings storage conditions, the reliability of the piezometric method may be questioned. The Seismic Cone Penetration Test (SCPTU) can meet high test standards. The results of the penetration tests closely identify conditions of sediments that determine the tailings water regime verified locally on the basis of pore water pressure dissipation tests. On the other hand, seismic measurements perfectly complement the characteristics of sediments in terms of their saturation. The analysis of the results of SCPTU implemented in the tailings massif also showed that below the phreatic surface, a zone of not fully saturated tailings can be found. Its presence improves the stability conditions of the tailings massif and dams, but also limits the possibility of the static liquefaction of tailings.
20 September 2017 in Journal of Fluids Engineering
Fine solid materials can be transported with the use of water as a carrier liquid. From the practical point of view, the economy of designing and maintenance is usually the most important factor. That way of transport has a lot of advantages for many industry processes. However, the problems of pressure flow are more complicated for slurries than for liquids. The transient flow is one of the most difficult problems to describe. A deep analysis of transients in slurries is crucial, both theoretically and practically. In this paper, the analysis of the transient flow in high-density polyethylene pressure pipelines is described. At the first stage, a laboratory model was build. Experiments made for different volume concentrations were performed. The results were used to build a numerical model of transient flow, which was the second stage of investigation. Due to relatively difficult description of the volumetric concentration bottom layer depth, these parameters vary in time and volume of slurry, and an alternative approach was proposed. The equivalent density was introduced to express the unknown parameters. Performed numerical simulations lead to promising results. In all analyzed episodes, the calculated pressure characteristics demonstrated satisfactory coincidence with observations.
The paper presents the approach for optimization of preventive/technological measures increasing the safety of tailings pond dams. It is based on the combined use of monitoring results as well as advanced 3D finite element (FE) modeling. Under consideration was the eastern dam of Zelazny Most Tailings Storage Facility (TSF). As part of the work, four numerical models of the dam and the subsoil, differing in the spatial arrangement of the soil layers, were created. For this purpose, the kriging technique was used. The numerical models were calibrated against the measurements from the monitoring system. In particular the readings acquired from benchmarks, piezometers and inclinometers were used. The optimization of preventive measures was performed for the model that showed the best general fit to the monitoring data. The spatial distribution and installation time of relief wells were both optimized. It was shown that the optimized system of relief wells provides the required safety margin.