?Luossavaara-Kiirunavaara AB (LKAB), an iron ore company with mines in northern Sweden is continuously considering new technologies for handling, transportation and disposal of waste rock and tailings. The mines and concentration facilities are located north of the Arctic Circle which in Scandinavia means an average temperature of about 0° C. Snow from mid-October to mid-May. In winter the temperature may reach -35 to -40° C during weeklong cold spells. At the Svappavaara mine early technical-economical feasibility considerations together with expected space limitations in the concentrator area favored location of two thickened tailings thickeners on a hill close to the disposal area about 1600 m away from the concentrating plant. In this way only short distance pumping of thickened slurry is required and warm process water is recovered directly by gravity from the thickener to the concentrating plant. A thickener of a high-density type with 18 m diameter was first installed. Four years later an additional thickener of paste type with diameter 24 m was put into operation. The design (maximum) capacities were 115 and 275 tph (tons per hour) for the 18 m and 24 m thickeners, respectively, with solids flux rates of 0.45 and 0.6 ton/m2h. Both are planned for common use for 390 tph within a few years. The tailings product is characterized by an average particle size of about 30 µm with a maximum of about 500 µm and about 40 % passing 20 µm. Solids density about 3000 kg/m3. A solids concentration by mass of 70 % was considered sufficient for deposition at a slope of up to 3 %. The objective is to present and discuss the performance of the thickening, transportation and deposition systems during the commission stages and first years of operation. The aim is also to describe how initial conditions related to changes in the tailings production rate together with climatic conditions called for robust by-pass arrangements. Furthermore, complicating factors related to the choice of auxiliary equipment and instrumentation for central functions are discussed.
Over the last few years, there has been a substantial increase in the degree of complexity of requirements regarding the licensing of tailings dams in Brazil. The stacking of filtered tailings is currently proposed as an alternative solution for tailings storage facilities; however, there are numerous challenges to understand and manage these structures in regions of high rainfall and high disposal rates. In this context, the objective of this article is to evaluate the liquefaction susceptibility of filtered iron ore tailings, based on field (piezocone) and laboratory tests (characterization and triaxial compression), both performed at an experimental landfill, located in the Iron Quadrangle (Quadrilátero Ferrífero), Minas Gerais state, Brazil. Therefore, a few methodologies were used to evaluate liquefaction susceptibility by means of the critical state theory, furthermore the fragility index of the material were also evaluated. Results indicated that the constructive method used in the experimental landfill (i.e., compaction energy, moisture and layer thickness) resulted in variability in the in-situ void ratio, indicating susceptibility to liquefaction for materials on depths greater than 0.75 m from compaction surface. In addition, from laboratory tests it was possible to determine the critical state line of the filtered tailings.
Railways that deliver ore from mines to market are critical to an operations viability. Two examples of such railways include the Rio Tinto Iron Ore (RTIO) railway in the Pilbara region of Western Australia, and the Iron Ore Company of Canada (IOC) railway in northeastern Canada. Both railways are the only transportation mode from 17 mine sites to the ports to deliver their products to markets; annually, these railways ship over 330 million tonnes of iron ore (RTIO) and over 10 million tonnes of iron pellets (IOC). Although separated by over 16,000 km, different terrains, climates and operating regulations, these railways face similar challenges with respect to assessing and managing the risks associated with geohazards, in particular rockfall, landslides, and flooding geohazards. This paper presents risk-based frameworks for the IOC and RTIO railways, and the development of web and mobile based platforms to support effective geohazard risk-management practices within corporate risk frameworks. The output risk rating for each credible geohazard affecting the railway is used to support risk management through inspections, remediation projects and optimisation of maintenance and in situ or remote monitoring efforts. The geohazard management systems are also used in combination with live monitoring data to actively alert railway operators of changing conditions and potential triggering events, such as flooding or heavy rainfall. The systems that will be presented are used to support decisionmaking and communication of geohazard threats within their organisations.
?This study aims to analyses the use of high-pressure filter presses in the dewatering of slurry resulting from mineral processing, especially iron ore mining tailings and slimes. The current practice problems of deposition of fines in tailing dams were analyzed, as well as the new challenges faced by the sector in relation to water scarcity and energy efficiency. Are listed technological differentials implemented in Matec filter presses and analyzed the benefits in application of this technology, such as higher water recovery, reduce of environmental impacts and reduce of operating costs for handling and disposal of waste. Lastly, we analyze the filtration tests performed on iron ore tailings and slimes and a case study.