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https://www.ausimmbulletin.com/feature/waste-not-want-not-rethinking-the-tailings-and-mine-waste-issue/
POSTED DE CEMB ER 20 16
Waste not, want not
rethinking the tailings
and mine waste issue
By Dirk van Zyl, University of British Columbia; Deborah Shields, Colorado State
University and Politecnico di Torino; Zach Agioutantis, University of Kentucky; and
Susan Joyce, On Common Ground Consultants Inc
An exploration of ideas that could help make the reuse of waste and
tailings more economically viable
Over the past 15 years, the mining industry has begun to incorporate the concepts of
sustainable development and sustainable mining practice across the life cycle of mineral
operations. This requires addressing economic issues and community impacts and concerns,
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as well as environmental protection, and is captured in part by the phrase ‘design for
sustainability’ (McClellan et al, 2009). Over the same period, the industry has seen a gradual
decrease in ore grades for many mineral commodities. As a result, large volumes of tailings and
mine waste rock are being produced around the world, and it is expected that the annual
production volumes of these materials will increase, even if there is not a significant change in
the demand for materials.
Another related thread of change has been the realisation that societies need to move away
from linear economies (raw materials, production, consumption and disposal) toward more
circular ones. This will help societies become more resource efficient, which is defined by the
United Nations Environment Program (2011) as reducing the total environmental impact of the
production and consumption of goods and services, from raw material extraction to final use
and disposal. The goal is to create ‘more with less’ and deliver greater value with less input.
Circular economies require thinking in terms of the waste hierarchy (reduce, reuse, repurpose,
recycle, recover, landfill). The challenge is that the waste hierarchy was originally designed to
address embodied mineral content in products, rather than mine waste and tailings
generation. It will need to be reconsidered in a mine life cycle context, focusing on a value-
based conception of waste (Van Ewijk and Stegemann, 2016).
In parallel with these changes, it has remained an imperative in the mining industry to dispose
of waste materials as economically as possible while protecting the environment. Single
handling of these materials has been the main target, which reduces the life cycle costs of
their management but may make reuse of waste and tailings technically more difficult or
economically infeasible.
This article explores a rethinking of the large-volume earthen material waste issue at mines.
The underlying theme is that some or all of these materials can be resources for the future
that potentially have value and so can positively contribute to sustainable development. These
resources can:
offer economic gains to firms, communities and societies
contribute to environmental wellbeing
enhance social interactions with the previously mined landscape
reduce governance commitments if proper policies are put in place.
Each of these topics will be briefly explored. This will be followed by a discussion of
approaches to manage design and operations to allow for future resource recovery.
Economic gains
Magnus Ericsson from the Luleå University of Technology has reported that there are
currently approximately 75 major tailings re-mining projects globally. Minerals such as gold,
diamonds and copper are being reclaimed. One of the most successful economic projects in
using tailings as a resource is the Ergo Project, which involves large-scale tailings
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hydraulicking and reprocessing of gold tailings in the Johannesburg area of South Africa. The
project was established in the 1980s and has gone through multiple renewals. After removing
the tailings and recovering gold and uranium, the land is made available for housing
developments. The remaining tailings are deposited in a consolidated tailings facility south of
the city.
Another recent example of land reuse is Peabody Coal’s Ereen coal mine reclamation in
Mongolia, in which a large portion of the reclaimed land was turned into hay paddocks that the
local herding community can harvest for their own herds or sell for income. Local herders also
serve as environmental monitors, providing them with an additional income stream (The Asia
Foundation, 2009).
In another major project being undertaken in Kimberley, South Africa, De Beers is processing
tailings from its now-closed local diamond operations. Its tailings plant is producing 800?000
carats of diamonds a year. However, this project is not without challenges as illegal mining is
common. The company reports illegal miners caught on their land to the police, but that has
not stopped the problem because many local people believe that De Beers is done with mining
and the land where the tailings are stored belongs to the town, not the company.
Where longer-term care and maintenance is required, upskilling of local residents to carry out
environmental monitoring and maintenance work is an obvious source of ongoing income,
particularly for mines located in remote rural areas of developing countries where such
income may make a significant contribution to families and communities. In a clear example of
‘shared value creation’, this type of arrangement is more cost-effective than the complicated
travel and logistical arrangements required to send outsiders to the site for monitoring, while
contributing income and increased capacity to the local community. In this context, shared
value means aligning the business interests of extractives companies with community needs
and priorities.
It takes time and energy to set up the governance mechanisms so that these arrangements are
consistent with local community norms and capacities, and to ensure that the new resources
continue to be shared collectively.
Environmental well-being
The design and construction of tailings containment structures is usually part of every major
mining project. It is much more effective to concentrate or clean the mined product close to
the mining facility than transport it elsewhere.
In cases where mining does not require backfilling of stopes, storing tailings back in
underground mine voids is a rather expensive exercise and is commonly avoided. However,
following a number of tailings dam failures, mine planners have started considering the idea of
underground permanent storage. Alternatively, contemporary mining facility designs provide
post-mining land uses of tailings impoundments as these are mandated by environmental
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legislation and permitting procedures in many parts of the world. For example, a number of
tailings impoundments in North America are being turned into solar farms. In addition, tailings
ponds may be designed ex ante to have better environmental properties (Edraki et al, 2014),
which can be accomplished by better management of the water, reagents and minerals
remaining in the tailings. For example, sulfide flotation has been implemented for tailings to
produce non-reacting products that will not produce acid or sulfates. This approach is also
being investigated for a number of development projects.
However, very few designs view tailings impoundments as a potential resource. Recent
research (Harrison, Power and?Dipple, 2012) shows that some tailings (ultramafic) can be used
effectively in the sequestration of carbon by converting CO2 to carbonate minerals.
Another technology that is being investigated on a worldwide scale is geopolymerisation.
Under this process, a ‘paste’ can be created through a relatively simple chemical reaction.
Depending on the components present, the paste can be designed to ‘bond’ with different
waste streams, such as mine tailings. This process can transform tailings into a new supply of
raw materials for infrastructure construction, including roads and highways (Ahmari, Chen and
Zhang, 2012) and even commercial buildings (Ahmari and Zhang, 2012).
Natural Resources Canada has a green mining initiative that ‘targets the development of
innovative energy-efficient technologies required for mining to leave behind only clean water,
rehabilitated landscapes and healthy ecosystems’ (Natural Resources Canada, 2016). Recent
publications (Tisch et al, 2012, 2015) present the results of studies on biomass production on
closed tailings facilities for green energy production.
Environmental accidents are usually the result of the alignment of several adverse scenarios.
Statistically speaking, there is always a probability that an accident will occur. The failure of
the Fundão tailings dam at the Samarco mine in Brazil is a recent example of how the
cumulative effects of multiple small design and construction flaws, combined with operating
decisions, can lead to an environmental and social disaster (Morgenstern et al, 2016).? As such,
an environmentally friendly tailings facility could be designed as a group of smaller facilities
with multiple end uses that can diversify potential impacts, reducing the risk profile both for
the operation and for other stakeholders, including local communities.
The concept of redesigning for smaller, multiple facilities also opens potential new
opportunities for post-mining management or economic opportunities as ‘debundling’ from
large, technologically complex and high-capex designs provides more opportunities for
national or local businesses to play a role.
Social interactions with the landscape
It is common to construct mine waste facilities as geometric forms that do not necessarily
approximate features in the natural environment. Landform engineering is an important
aspect of the mine closure and reclamation process. Landscape architectural planning during
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the early stages of mine planning can also be implemented. Large flat areas on the top of mine
waste facilities may be used as future agricultural lands, an activity currently being developed
in China. Conversely, where potential future land use is not a pressing need, community
members may prefer a landscape that has a more natural form. To the degree that (non-liquid)
waste and tailings piles are given shapes that are inconsistent with natural land forms (ie too
many angles and flat tops and not enough curvature and randomness), they may be considered
unattractive.
In either case, an important aspect of achieving a design that contributes to social well-being
is the early engagement of communities to understand their expectations of the mine
landscape during and following operations. This implies an early engagement process, but
relationships to the landscape are not necessarily unchanging, nor are social needs or values.
Engagement should be ongoing and agreements revisited on a periodic basis as new
opportunities may develop or the local peoples’ needs or expectations of post-mine land use
may change over time. This has been seen in community agreements that were supposed to
serve for the full mine-life of a more than 20-year operation, yet as employment, educational
levels and generational changes advance, new agreements are needed to reflect the changing
needs and aspirations of the parties. Early impact and benefit agreements in Canada did not
include consideration of the need to update agreements, but second-generation agreements
today tend to be negotiated as ‘living documents’.
Mine waste facilities can be long-term regulatory and corporate liabilities if they produce
contaminated effluents. Acid rock drainage and metal leaching is a major problem at many
mine sites and may be difficult, or even impossible, to control once started. However, these
facilities may still be a resource for the recovery of metals. Further technology development
may allow for the future recovery of low-concentration metals from the effluent.
Mine waste governance
Ongoing monitoring of mine waste facilities during the post-closure period may provide
employment to local communities. Ideally, these sites should be relinquished from operator to
original landowner or new institution after satisfactory completion of closure activities,
thereby reducing governance commitments. However, sufficient regulatory oversight should
be exercised to identify potential future site disturbances for the recovery of metals or other
perceived resources.
There are several governance implications from the community and civil society side. First, in
many developing countries, there is little or no regulatory requirement or oversight of the
closure process for operations and even less so for exploration. As a result, assuming a
meaningful/credible regulatory role may not be appropriate at this stage. However, progress
is being made in many jurisdictions in this regard, and it is expected that pressure from
communities, as well as from financial institutions in accordance with the Equator Principles,
will influence more uniform international approaches.
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Problems may still be posed when there are ongoing environmental liabilities associated with a
project. In this case, longer-term bonding may be needed as a long-term or perpetual care site
cannot be considered closed or the liability relinquished. The governance commitments
frommining companies must also be robust for sites that require ongoing monitoring,
maintenance and operations (such as water treatment plants).
A local institution to receive funding, manage the oversight role and pay local monitors can be
an intermediary strategy for transferring economic opportunities to the local area when there
is poor government oversight and a lack of capacity in the local community. This could be an
existing institution, or a foundation could be set up with ongoing funding that pays for
environmental management of a site while providing ongoing seed money for social
development programs. These programs could improve local social stability and reduce the
risks to the remediated areas that can stem from poverty and pressure on resources.
Management opportunities
A range of options is available to manage project design, operations and closure to increase the
opportunities for resource recovery. These options include:
Ongoing community engagement, especially with respect to envisioning the future of
the area.
Careful consideration of a wide range of alternatives for all aspects of project
development, including mining method, processing options, mine waste materials
management options and site selection for mine waste facilities.
Complete characterisation of all materials to identify the presence of specialty metals
(eg rhenium in copper ore bodies), combined with a value-based conception of waste
that estimates the resource value of the materials. This should be supplemented with a
rethinking of the waste hierarchy in the context of mining and mineral processing so
that there is not an automatic presumption of disposal.
The EU is working to devise a new mineral policy, the goal of which will be to
incorporate both primary and secondary minerals in mineral supply/production policy.
The challenge is that policy, law and regulation of mining in virtually all cases resides in
separate legislation and ministries to waste management. If mine waste and tailings are
to be redefined as sources of secondary materials, there will need to be coordination
across government agencies to ensure that the rules within one domain do not conflict
with rules in another.
Life cycle planning for the project on an ongoing basis, combined with design for
sustainability. For waste and tailings, this implies storage in a manner that will make
reprocessing of waste and tailings more feasible, rather than less. This may potentially
conflict with the goal of minimising the surface footprint of waste.
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To identify best-fit, post-closure uses and align design, management and closure
activities, work should be done early in the project cycle to identify economically useful
and desired scenarios after closure, with input from stakeholders.
Increasingly, dialogue and early-stage agreements are being used to address the
concerns of local populations and to set up agreements to protect key social and
environmental values. For effective planning, the economic use after closure should
become part of the prior agreements with communities that can contribute to overall
project acceptability.
The challenge of developing participatory mechanisms to ensure that the input of local
populations is representative and includes the people who are most concerned with and
effected by the impact.
Post-mining land use is an important aspect of mine planning. It is possible that specific
plans for future site uses are developed with community support and that the project is
sold to another company. While the future site use plans can be transferred, the new
owner may consider ongoing resource recovery from the mine waste or new orebodies
as the preferred site option. This will put the new owner’s expectations in direct conflict
with the carefully assembled future land use plans, and the new owner will have to work
closely with the community to maintain its support as the plans develop.
Careful record keeping of material movement to waste rock and tailings facilities is
essential to allow future identification of material locations. Without having good
records of
material locations, selective re-mining may not be possible.
Complete, as-built plans should be prepared during operations and closure
to confirm the locations of all potential waste materials that must not be disturbed and
the thickness of engineered covers etc. This information is essential for ongoing
environmental protection if re-mining is done.
Challenges
Operational and societal challenges remain, and more will be identified as the efforts of
embracing the potential of mine waste as a resource intensifies. The first challenge is to agree
on the stakeholders and their approach to identifying the data collection needs for a specific
project, as well as identifying the entity that will be responsible for maintaining the site
records. Corporate control of this may not be the optimal approach, but governments may not
be in a position to be the custodians of it either.
References
Ahmari S, Chen R and Zhang L, 2012. Utilization of mine tailings as road base material, in
Proceedings GeoCongress 2012, pp 3654-3661.
Ahmari S and Zhang L, 2012. Production of eco-friendly bricks from copper mine tailings
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through geopolymerization, Construction and Building Materials, 29:323-331.
Asia Foundation, The, 2009. Land reclamation: a Mongolian citizen’s guide [online]. Available
from: http://sgpmongolia.org/upload/Land%20reclamation.pdf
Edraki M, Baumgartl T, Manlapig E, Bradshaw D, Franks D and Moran C, 2014. Designing mine
tailings for better environmental, social, and economic outcomes: a review of alternative
approaches, Journal of Cleaner Production, 84:411-420.
Harrison A L, Power I M and Dipple G M, 2012. Accelerated carbonation of brucite in mine
tailings for carbon sequestration, Environmental Science & Technology, 47(1): 126-134.
McClellan B, Corder G, Giurco D and Green S, 2009. Incorporating sustainable development in
the design of mineral processing operations – review and analysis of current approaches,
Journal of Cleaner Production, 17:1414-1425.
Morgenstern N, Vick S, Viotti C and Watts B, 2016. Report on the Immediate Causes of the
Failure of the Fundão Dam. Fundão Tailings Dam Review Panel.
Natural Resources Canda, 2016. Green mining initiative [online]. Available from:
www.nrcan.gc.ca/mining-materials/green-mining/8178
Tisch B, Beauchemin S, Clemente J and Zinck J, 2015. Innovations in tailings management: from
risk to revenue, in Proceedings CIM Montreal 2015.
Tisch B, Hargreaves J, Beckett P, Lock A and Spiers G, 2012. Post-mining agriculture for
biofuels on tailings: an overview of results from the Green Mines Green Energy (GMGE)
initiative, in Proceedings ICARD Conference, Ottawa.
Van Ewijk S and Stegemann J, 2016. Limitations of the waste hierarchy for achieving absolute
reductions in material throughput, Journal of Cleaner Production, 132:122-128.
United Nations Environment Project, 2011. Decoupling natural resource use and environmental
impacts from economic growth, A Report of the Working Group on Decoupling to the
International Resource Panel. Fischer-Kowalski M, Swilling M, von Weizsäcker EU, Ren Y,
Moriguchi Y, Crane W, Krausmann F, Eisenmenger N, Giljum S, Hennicke P, Romero Lankao P,
Siriban Manalang A, Sewerin S.
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... Tailings valorization means the recovery of residual metals and utilization of the mineral matrix. Hazardous waste can be transformed into valuable secondary metal sources (van Zyl et al., 2016;Solomons, 2017) combining metals recovery and environmental management (Bellenfant et al., 2013) with developed technologies, such as biomining (Johnson, 2014). One single tailings area can contain valuable and critical metals worth up to hundreds of millions of euros (e.g., Metals X Ltd, 2017). ...
... One single tailings area can contain valuable and critical metals worth up to hundreds of millions of euros (e.g., Metals X Ltd, 2017). Tailings have already been quarried and crushed, which significantly lowers the actual treatment costs compared to primary ores needing mining since mining and processing can constitute 40e60% of the total mineral processing costs (Cox et al., 2011;Zhao et al., 2012;Patent US, 2012). Mine wastes contain mineral and energy resources, which may become valuable, e.g., through the development of new technologies, new market demands or improved commodity prices (Lottermoser, 2011). ...
... Mine wastes contain mineral and energy resources, which may become valuable, e.g., through the development of new technologies, new market demands or improved commodity prices (Lottermoser, 2011). Currently, it is estimated that approximately 75 major tailings re-mining projects are taking place globally on the reclamation of gold, diamonds, and copper (van Zyl et al., 2016). ...
Article
Current management of mining waste is based on linear economy thinking. However, the use of mining waste as a raw material resource can be one solution to the limited metal supply. The objective of this study was to fill in the knowledge gaps of business opportunities, drivers, needs and barriers for tailings valorization, since the transformation towards a circular economy needs advancements in understanding these factors. Based on a workshop and theme interviews, the utilization of tailings in the mining industry is currently in its infancy, but there is clear raw material potential for the future. The handling of sidestreams at mine sites depends on mine lifecycle. The identified opportunities and drivers were categorized under the circular economy mindset, technological, environmental, institutional and economic drivers. The needs were new value chains, technology development, the decrease in the amount of waste, stability, taxation, and predictability of regulation. Challenges and bottlenecks were categorized under new value chains, technological, environmental, institutional, economic and knowledge bottlenecks. The identified needs and barriers need to be properly addressed to speed up the transformation towards the circular economy in the mining industry.
... However, there is need to assess the economic stability of the mining waste reprocessing via a cost and benefits method to include the economic value of metals recovered, the cost of the reprocessing, the cost of the residual materials, the final and long-term safe disposal and the environmental benefit of this final disposal [126]. It has been stated that globally, there are presently about 75 major tailings mining reprocessing projects [127]. Economically, Ergo Project is one of the utmost prosperous projects that utilizes tailings as a resource. ...
... Relatively, in the course of this process, a 'paste' can be made via a simple chemical reaction. Contingent on the components available in the paste, the paste could be designed to 'bond' with diverse waste streams, like mine tailings and mine dumps [127]. This process can convert tailings or waste dump into a novel raw materials that will be supply for infrastructure construction such as roads, highways and commercial buildings [136]. ...
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Mining is very vital to the production of goods, services and infrastructure; it advances the quality of lives in the society. However, the possible hazard of waste and radioactivity generated by mining, dumping and tailing, has called on the society to find ways of seeking remedy that will adequately treat mining waste from mine dump, tailing and abandoned mine. Mine waste reuse and recycling in mining industries could offer cost-effective benefits through offsetting raw material requirements and decreasing the volumes of waste to be managed. This review discussed mine dump pollution monitoring and mine dump management strategies for some selected countries. Impact and mechanism of mine damage to the environment was discussed together with the remediation principles. It further examines the mining Act and regulations of the same selected countries. Emphasised was placed on the enforcement of environmental laws, regulations, and standards. Practical ways in which country’s state authority and civil society can keep a close watch and enhance the enforcement of laws and regulations were highlighted. The prediction for the control of mineral exploration and environmental assessment was also discussed for executing a specific control to take preventive measures. Management techniques used in combating the impact of mine dump, stockpiles and tailing on the environment were discussed. In addition, radioactivity in mine and its monitoring and control was discussed.
... van Zil et al. (2016) Why waste is important? Because waste occupies large spaces and is potentially dangerous from a physical and chemical point of view. ...
... Mine wastes, they grow and grow …(van Zil et al 2016). ...
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The southeast of Spain is a mythical land for geology in Europe. Its geological marvels include a Miocene volcanic chain, marine sedimentary basins in which were recorded the events of the Messinian Salinity Crisis and the two westernmost metamorphic complexes of the Alpine chain: Nevado Filábride and Alpujárride. This is only “the geology” of this realm, because in relation to the volcanism, important clusters of ore deposits were formed, among them, Rodalquilar (gold), and Mazarrón and La Unión (lead-zinc), which gave rise to famous mining districts. These two new GMMM documents are “teaching field guides”, because the reader will find in them more than just raw data and photos for a “geotour”. The authors go further explaining the regional and local geology, the history of mining and how mining was done, and how the ore deposits were formed, also providing a base for the analysis of the environmental scenario left after mining ceased. http://www.aulados.net/GEMM/Libros_Manuales/Field_Teaching_Guide_Mazarron_La_Union.pdf
... According to Van Zyl et al. [35], there is currently approximately 75 major mine tailing re-mining projects underway around the world. The ERGO project, located in Johannesburg, South Africa, is one successful venture that re-mines gold from mine tailings [35]. Other examples include the Kaltails project, which was established to reprocess tailings from mine dumps in Kalgoorlie, Western Australia, in order to obtain gold [36,37]. ...
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Mining has advanced primarily through the use of two strategies: pyrometallurgy and hydrometallurgy. Both have been used successfully to extract valuable metals from ore deposits. These strategies, without a doubt, harm the environment. Furthermore, due to decades of excessive mining, there has been a global decline in high-grade ores. This has resulted in a decrease in valuable metal supply, which has prompted a reconsideration of these traditional strategies, as the industry faces the current challenge of accessing the highly sought-after valuable metals from low-grade ores. This review outlines these challenges in detail, provides insights into metal recovery issues, and describes technological advances being made to address the issues associated with dealing with low-grade metals. It also discusses the pragmatic paradigm shift that necessitates the use of biotechnological solutions provided by bioleaching, particularly its environmental friendliness. However, it goes on to criticize the shortcomings of bioleaching while highlighting the potential solutions provided by a bespoke approach that integrates research applications from omics technologies and their applications in the adaptation of bioleaching microorganisms and their interaction with the harsh environments associated with metal ore degradation.
... However, those wastes, or what we think of as wastes, can be transformed into useable products via reuse, recycling, and recovery. This is very important to decrease the demand for new nonrenewable resource quarries and the associated environmental impacts, and more importantly to generate economic profits [53][54][55][56]. The need to explore alternative and sustainable resources is becoming an urgent task for decision makers and stakeholders. ...
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The phosphate industry produces huge volumes of waste (hundred million tons per year). These wastes are generally surface landfilled, leading to significant environmental impacts and a large footprint. The current practices of phosphate waste management, the typology of the waste streams and their characteristics, and finally their potential applications are reviewed. All the waste streams generated during the life cycle of phosphoric acid production going from the extraction of phosphate rock to its enrichment and transformation are considered. Great circularity opportunities have been identified and they aim (i) to recover the residual phosphorus and other critical minerals and metals, and (ii) to consider phosphate wastes as alternative resources in the civil engineering and building sectors. The purpose is to shift from linear thinking to circular thinking where synergy between different mining and other industries is highly encouraged. By doing so, opportunities to safeguard natural resources and to minimize the environmental and societal impacts are limitless. However, many challenges are still limiting this shift: economic and technical constraints, societal and policy-makers' awareness, regulation harmonization and finally knowledge gaps. More efforts and investment in research and development are still required to reach the zero-waste target.
... While some authors state that the mining industry is apart and excluded from restorative circular loops (Fig. 2) [228], the efforts made by mining companies' contributions to a circular economy have been overlooked. For example, there have been approximately 75 major tailings remining projects that aim to extract gold, diamonds and copper [230]. These remining activities do not only provide mineral resources, but they also conserve finite mineral resources and reduce environmental impacts of waste repositories and mine sites. ...
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Note that significant contributors are Bernd Lottermoser, Eberhardt Falck, Franke Winde, Sven Altfelder, Olena Pylypenko. Typically, discussions of the uranium production cycle are focused on either the economic extraction of resources, or on the environmental and remediation aspects as parallel aspects in a linear cradle-to-grave process. In this publication, resource evaluation is expanded to the full life of the mine to include evaluation of resources in residual waste products. This is viewed in the context of potential reuse or remining of so-called anthropogenic resources in a circular economy. The publication is intended to not only provide a preliminary inventory of uranium contained in mine wastes including the desirable goal of comprehensive extraction in the (uranium) mining industry, but also to provide an initial framework to integrate this aim with those of environmental and remediation considerations in achieving zero waste.
... In fact, their repurposing can be a suitable approach to give them a second life in terms of circular economy (e.g. maximization of mineral exploitation), while mitigating the possible environmental impacts related to their long-term disposal [13,20,21]. The repurposing and valorization of mine waste is also in line with the United Nations' Sustainable Development Goals (SDGs) as well as the implementation of the Paris Agreement. ...
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For decades, the world has experienced a steadily increasing demand in the extraction of a variety of different minerals from the earth's crust through mining processes. This has resulted in two major consequences: i) depletion of limited mineral resources of the earth, and ii) generation of large amounts of residual products in the mining and metallurgical sectors, that are disposed of in tailing ponds or landfill sites. These issues have caused that the world is encountering with incredibly serious economic and environmental challenges. Reuse, repurposing and valorization of these residues have been determined as effective and sustainable approaches towards struggling with economic and environmental issues related to the exploitation of low-grade deposits. These residues are divided into several categories according to their chemical and mineralogical compositions, since these parameters play essential roles in their repurposing/valorization. Among these residues, aluminosilicate bearing residues have demonstrated promising potential as inexpensive raw resources to produce valuable materials. In the recent years, these residues have been intensively investigated for their use in the production of cost-effective zeolites, which are crucial materials for catalysis and adsorption–separation industries. This alternative in zeolite production is of continuous interest in the field of zeolite science due to: i) important reduction in zeolite production costs, ii) sustainable development concepts as well as iii) helping to tackle the environmental concerns related to long-term management of residues. Herein, the endeavor is to discuss about the state-of-the-art technologies for zeolitization of aluminosilicate bearing residues including coal fly ash, clay minerals residues, Li slag, Al production residues, with an emphasis on the ongoing struggles in improvement of their corresponding zeolitization processes.
... A significant shift in public opinion on the management of waste facilities and the ability and intent to repurpose tailings materials (Van Zyl et al., 2017) has changed the economic driving force for many projects. Examples are noted in this Paper where this has been achieved. ...
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Supply of resources, a growing population, and environmental pollution are some of the main challenges facing the contemporary world. The rapid development of mining activities has produced huge amounts of waste. This waste, found in abandoned mine sites, provides the potential opportunity of extracting raw material. The current study, therefore, focuses on testing the validation of a shared methodology to recover extractive waste from abandoned mines, and applies this methodology to a case study in Gorno, northwest Italy. The methods focused on: (1) analyzing the impact of tailings and fine fraction of waste rock (<2 mm) on plants (Cress - Lepidium Sativum) to assess usability of both as soil additive, and (2) recovering raw materials from tailings and coarse fraction (>2 mm) of waste rock, by means of dressing methods like wet shaking table and froth flotation. The results indicated that the fine fraction of waste rock and tailings did not have detrimental effects on seed germination; however, there was marked decrease in plant growth. As for the recovery of raw materials, the coarse waste rock samples, crushed to <0.5 mm, produced a recovery of Cd, Ga, and Zn—as much as 66%, 56%, and 64%, respectively—using the wet shaking table. The same samples when crushed to 0.063–0.16 mm and used for froth flotation produced a recovery of Cd, Ga, and Zn of up to 61%, 72%, and 47%, respectively. The flotation experiment on tailings showed a recovery of Cd, Ga and Zn at pH 7 of 33%, 6% and 29% respectively. The present investigation highlights the methodologies used for extracting raw materials from extractive waste.
Article
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Dematerialization can serve as a measurable and straightforward strategy for sustainability and requires changes in management of material inputs and waste outputs of the economy. Currently, waste management is strongly inspired by the waste hierarchy, an influential philosophy in waste and resource management that prioritizes practices ranging from waste prevention to landfill. Despite the inclusion and prioritization of prevention in the hierarchy, the positive contribution of the application of the waste hierarchy to dematerializing the economy is not inevitable, nor has it been conclusively studied. In this paper, the waste hierarchy is analyzed on a conceptual level by studying its original aims, its potential to fulfill those aims, and its actual policy implementation. Issues with the hierarchy include limited specification and implementation of prevention, a lack of guidance for choosing amongst the levels of the hierarchy and the absence of a distinction between open-loop and closed-loop recycling. Also, the hierarchy only communicates relative priorities and therefore does not support decisions that affect other sectors as well as waste management. The article concludes that the waste hierarchy in its current form is an insufficient foundation for waste and resource policy to achieve absolute reductions in material throughput. Suggested improvements are the adoption of a value-based conception of waste and related collection practices, more stringent and targeted policies on least desirable options like landfill, the specification of waste management targets based on dematerialization ambitions, and the use of the waste hierarchy within a resource productivity-oriented framework.
Conference Paper
In this paper, a preliminary study is performed on utilization of copper mine tailings as road base material through geopolymerization. The mine tailings studied is from a copper mine in Arizona, USA and contains mainly silica, alumina and calcium. Sodium hydroxide (NaOH) solution is used as the alkaline geopolymerization agent. Unconfined compression tests are conducted on compacted mine tailings specimens prepared at different NaOH content and cured for different time at room temperature to measure their unconfined compressive strength (UCS). The results show that when an appropriate amount NaOH is used, the strength of compacted mine tailings can be improved. Based on this preliminary study, it can be concluded that mine tailings are a promising road base material if the geopolymerization technology is utilized.
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This paper studies the feasibility of utilizing copper mine tailings for production of eco-friendly bricks based on the geopolymerization technology. The procedure for producing the bricks simply includes mixing the tailings with an alkaline solution, forming the brick by compressing the mixture within a mold under a specified pressure, and curing the brick at a slightly elevated temperature. Unlike the conventional method for producing bricks, the new procedure neither uses clay and shale nor requires high temperature kiln firing, having significant environmental and ecological benefits. In this study, the effects of four major factors, sodium hydroxide (NaOH) solution concentration (10 and 15M), water content (8–18%), forming pressure (0–35MPa), and curing temperature (60–120°C), on the physical and mechanical properties of copper mine tailings-based geopolymer bricks are investigated using water absorption and unconfined compression tests. Scanning electron microscopy (SEM) imaging and X-ray diffraction (XRD) analysis are also performed to investigate the microstructure and phase composition of the mine tailings-based geopolymer bricks prepared at different conditions. The results show that copper mine tailings can be used to produce eco-friendly bricks based on the geopolymerization technology to meet the ASTM requirements.
Article
Atmospheric CO(2) is sequestered within ultramafic mine tailings via carbonation of Mg-bearing minerals. The rate of carbon sequestration at some mine sites appears to be limited by the rate of CO(2) supply. If carbonation of bulk tailings were accelerated, large mines may have the capacity to sequester millions of tonnes of CO(2) annually, offsetting mine emissions. The effect of supplying elevated partial pressures of CO(2) (pCO(2)) at 1 atm total pressure, on the carbonation rate of brucite [Mg(OH)(2)], a tailings mineral, was investigated experimentally with conditions emulating those at Mount Keith Nickel Mine (MKM), Western Australia. Brucite was carbonated to form nesquehonite [MgCO(3)·3H(2)O] at a rate that increased linearly with pCO(2). Geochemical modeling indicated that HCO(3)(-) promoted dissolution accelerated brucite carbonation. Isotopic and aqueous chemistry data indicated that equilibrium between CO(2) in the gas and aqueous phases was not attained during carbonation, yet nesquehonite precipitation occurred at equilibrium. This implies CO(2) uptake into solution remains rate-limiting for brucite carbonation at elevated pCO(2), providing potential for further acceleration. Accelerated brucite carbonation at MKM offers the potential to offset annual mine emissions by ∼22-57%. Recognition of mechanisms for brucite carbonation will guide ongoing work to accelerate Mg-silicate carbonation in tailings.
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This paper reviews the tools and methodologies used for incorporating sustainability considerations into the design of mineral processing operations. It was found that while there is a range of tools and methodologies that contribute to Design for Sustainability, there is no consistent, integrated approach to support the mineral industry in incorporating a greater level of sustainability into the design process. This paper identifies the required elements in such an approach and discusses the ways in which its development would progress the industry towards sustainability.
Land reclamation: a Mongolian citizen's guide
Asia Foundation, The, 2009. Land reclamation: a Mongolian citizen's guide [online]. Available from: http://sgpmongolia.org/upload/Land%20reclamation.pdf
Report on the Immediate Causes of the Failure of the Fundão Dam
  • N Morgenstern
  • S Vick
  • C Viotti
  • B Watts
Morgenstern N, Vick S, Viotti C and Watts B, 2016. Report on the Immediate Causes of the Failure of the Fundão Dam. Fundão Tailings Dam Review Panel.
Innovations in tailings management: from risk to revenue
  • B Tisch
  • S Beauchemin
  • Clemente J Zinck
Tisch B, Beauchemin S, Clemente J and Zinck J, 2015. Innovations in tailings management: from risk to revenue, in Proceedings CIM Montreal 2015.