Disposal of Waste Material in Mineral Processing

Mining is an important industry, accounting for 6.9% of global GDP. However, global development promotes accelerated demand, resulting in the accumulation of hazardous waste in land, sea, and air environments. It reached 7 billion tonnes of mine tailings generated yearly worldwide, and 19 billion solid tailings will be accumulated by 2025. Adding to this, the legacy of environmental damage from abandoned mines is worrying; in Canada there are around 10,000 abandoned mines, 50,000 in Australia, 6,000 in South Africa, and 9,500 coal mines in China, reaching 15,000 by 2050. In this scenario, restoration techniques from mining tailing have become increasingly discussed among scholars due to their potential to offer benefits towards reducing tailings levels, thereby reducing environmental pressure for the correct management and adding value to previously discarded waste. This review paper explores available literature on the main techniques of mining tailing recycling and reuse and discu...

The greatest challenge ahead of the Iron ore mining industry is to tackle the issues related to management of tailings. The tailing disposal and storage methods are sensitive to the environment and care must be taken to keep them at the helm. The method being practiced for disposing the tailings is as thickener underflow at around 45% solids. The development of paste thickener & deep cone thickener are encouraging and can dispose tailings at around 65% solids. However, they are yet to be established over different range of mineral tailings and also the economic aspects related to their transportation are yet to be resolved. Thus the development of improved tailing disposal system is of paramount importance and need of the hour. Filtration of tailings after thickening is an alternative to current practices. However, the suitability of this application is to be assessed for tailings of different nature. In this perspective an attempt has been made to assess the filterability of tailings generated from beneficiation of slimes from Donimalai area. From the studies it is evident that the application of filtration process to these tailings is encouraging. By adopting pressure filtration technique it was possible to produce filtered tailings with moisture in the range of 16 -21%. It is possible to get the filtration rate in the range of 200 -300 Kg/hr/m 2 while operating in the aforesaid moisture range. The greatest advantage ascertained is in the reduction in volume of tailings to be disposed by around 63% which is significant apart from increase in the water recovery by about 10%.

2015

Mining waste are regularly cited as potential secondary resources that could give access to residual concentrations of the exploited metals and also unrecovered metals, nowadays of economic importance for new high-tech applications. This article describes the investigation of three distinct mine tailings, and discusses the opportunity of re-processing such secondary mining resources, as part of the overall mining site management.

Interest in filtered tailings has grown significantly over the last several years, driven by social, environmental, and financial concerns around tailings storage facility (TSF) stability, water availability and water quality. Filtered tailings can provide benefits, such as 1) reduce water consumption; 2) potential to stack on the surface, reducing the facility footprint; 3) no reclaim water pool to manage, reducing the potential for accidental release and 4) potential to stack on top of existing TSFs or waste dumps, thereby reducing the "real-estate" issue by requiring construction of a new TSF.

A process was designed to recover a pile of 50-year-old mine tailings and transport them to a lined impoundment within two years (excluding permitting approval delays). To defray the costs of the tailings transport, a copper recovery process utilizing batch leaching with sulfuric acid was designed. The process is capable of treating 500 tons of ore per day, with a daily copper recovery of 23.3 tons. The proposed process is capable of recovering 85.5% of the copper present in the tailings pile. The total cost of the project was $5.76 million, while the money generated from recovering the copper was $4.93 million, resulting in a net present value of -$946,000. Although the design did not prove profitable, losses were minimized. Relocating and neutralizing the pile without attempting copper recovery resulted in a net present value of -$2.33 million. A third option which separated the tailings into +325 and -325 mesh fractions was rejected because its net present value was -$2.87 million. Due to the scarcity of available process water and pressures from nearby communities, government, and environmental agencies, the process was designed to recycle all water, thus resulting in a zero-discharge process over the lifetime of the operation. However, after the completion of the mineral recovery process, an approximate volume of 350,000 gallons will be treated to a pH above 7.0 and discharged into the impoundment. An Environmental, Safety, and Health (ES&H) plan was developed to ensure the safety of all personnel involved in the operation of the process. A community relations plan was developed to respond to the concerns of the neighboring community. This plan includes three town meetings, a hotline to answer questions and address complaints about the project, and newsletters sent out periodically to update the community on the progress of the project. The project meets the requirements of the New Mexico Mining Act of 1993 section 507C. Steps to obtain this permit will have to begin at least two years prior to startup. Once the permits are obtained, the process will operate for 260 sixteen-hour days, after which final site remediation procedures will be implemented. This report outlines possible techniques for remediation that depend upon the status of the soil underneath the tailings pile. The proposed process is comparable to existing mine tailings reclamation projects and includes features that represent sound environmental and engineering practices.

This paper summarizes research done on mine tailings management and explores new trends in the sustainable re-use of these tailings in construction activities. It is concluded that no research to date had addressed the issue of using hardened mine tailings as construction materials for temporary access unpaved roads in cold climates.

1999

With the unprecedented rate of mining and mineral processing over the past decade, there has been an increasing level of concern worldwide about the fate of tailings and the irreversible consequences of contaminant release through dust, tailings dam seepage, dam wall failure, or direct disposal of tailings into waterways. It is likely that in the future the mining of higher tonnages of lower grade ore and the possibility of more extreme weather events associated with global climatic change, may increase the risks associated with mine tailings management. In this paper we review alternative tailings management methods that aim to improve environmental, social and economic outcomes. Three approaches in particular are highlighted: paste and thickened tailings; tailings reuse, recycling and reprocessing; and proactive management (e.g. the integration of sulphide flotation with cemented paste backfill). The aim of the present study is to scope the opportunities that could be gained by developing an integrated research framework that traces tailings properties back to the orebody. In the future models could be constructed to optimise environmental, social and economic outcomes of tailings management across the value chain through integrated orebody characterisation, mine planning, processing, disposal, reprocessing, recycling and reuse.

Green Processing, 2002

Surface disposal of mining processing wastes is usually perceived as an undesirable consequence of meeting society's needs for metals and minerals. Environmental disasters associated with the discharge or storage of such wastes, though infrequent, can have very damaging consequences for the environment and the industry. Reducing or eliminating the potential for such events may be achieved by placing some or all of these processing wastes back into the voids created by the mining operations. Processing operations may limit or enhance the opportunities for using tailings and other waste products as a backfill material. Backfilling is a truly multidisciplinary process and requires the informed involvement of mining, metallurgical, engineering and environmental specialists. This paper describes the range of fill types currently being used in Australian mines, particularly those utilising processing wastes as constituents. It focuses on how processing operations can affect the suitability of these materials for the various types of fill, the resulting fill properties, fill performance and costs.

Journal of Cleaner Production, 2014

With the unprecedented rate of mining and mineral processing over the past decade, there has been an increasing level of concern worldwide about the fate of tailings and the irreversible consequences of contaminant release through dust, tailings dam seepage, dam wall failure, or direct disposal of tailings into waterways. It is likely that in the future the mining of higher tonnages of lower grade ore and the possibility of more extreme weather events associated with global climatic change, may increase the risks associated with mine tailings management. In this paper we review alternative tailings management methods that aim to improve environmental, social and economic outcomes. Three approaches in particular are highlighted: paste and thickened tailings; tailings reuse, recycling and reprocessing; and proactive management (e.g. the integration of sulphide flotation with cemented paste backfill). The aim of the present study is to scope the opportunities that could be gained by developing an integrated research framework that traces tailings properties back to the orebody. In the future models could be constructed to optimise environmental, social and economic outcomes of tailings management across the value chain through integrated orebody characterisation, mine planning, processing, disposal, reprocessing, recycling and reuse.

2015

The benefits of combining tailings and mine waste in a relatively homogenous manner, in which tailings just fill the voids between the waste rock particles while the waste rock maintains particleto-particle contact, has been the subject of study over the course of several years. Such a combination of materials could be used for a closure cover or as a singular large-scale facility to store both mine waste products. The possible benefits of this combination of materials include the creation of a deposit with the footprint smaller than two dedicated facilities, the shear strength of waste rock, the permeability of tailings, low oxygen diffusion rates, and theoretically a decreased potential to develop and emit acid rock drainage. If properly combined and placed, such a landform may be constructible with steep stacking angles, and it may exhibit a low potential for liquefaction. The authors briefly discuss previous work by others and provide information regarding some recently complete...

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Canadian Geotechnical Journal, 2001

A vast amount and variety of mine tailings are produced around the world each day. These mining wastes must be properly managed. To evaluate mine tailings disposal technology, the appropriate engineering properties of the tailings must be ascertained. The results of a laboratory investigation on the engineering properties of four different tailings are presented. First, some of the basic properties of the tailings are described. Large-strain consolidation tests and hydraulic conductivity tests are then described. The techniques for saturating and placing the tailings sample prior to carrying out the consolidation tests are given. Column drying and shrinkage tests for investigating the desiccation behavior of mine tailings are outlined. Furthermore, water retention characteristic tests using both the pressure-plate extractor and the saturated salt solution desiccator are outlined. Finally, shear strength parameter tests are described. The engineering properties derived from these tes...

Proceedings of the 16th International Seminar on Paste and Thickened Tailings, 2013

The use of filtering technology has improved considerably during the past few years, and tailings disposal facilities using filtered tailings are becoming more and more commonplace. Where once this method was only deemed suitable for relatively small-scale operations, technological advances are now being realised for large-scale operators. Often this application appears to be, and in fact is, relatively simple and straightforward. As with other tailings preparation methods, the use of filtered tailings provides no inherent panacea for tailings placement. Designers are advised to adopt designs thoughtfully, using site-specific data, information and tailings properties to ensure the method is employed rationally and that the resulting facility designs are flexible enough to accommodate changes to presumed operational design criteria. Practical experiences with facilities where less than optimal performance was achieved are presented.