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Review

Efficient Use of Water in Tailings Management: New Technologies and Environmental Strategies for the Future of Mining

by
Carlos Cacciuttolo
1,* and
Fernando Valenzuela
2
1
Civil Works and Geology Department, Catholic University of Temuco, Temuco 4780000, Chile
2
Unit Operations Laboratory, Faculty of Chemical and Pharmaceutical Sciences, Universidad de Chile, Santiago 8320000, Chile
*
Author to whom correspondence should be addressed.
Water 2022, 14(11), 1741; https://doi.org/10.3390/w14111741
Submission received: 21 April 2022 / Revised: 17 May 2022 / Accepted: 18 May 2022 / Published: 28 May 2022

Abstract

:
Nowadays, many major copper mining projects in desert areas with extremely dry climates, as in northern Chile and the southern coast of Peru, process sulfide ores at high production rates; in some cases over 100,000 metric tonnes per day (mtpd), generating large amounts of tailings, that are commonly managed and transported to tailings storage facilities (TSF) hydraulically using fresh water. Considering the extremely dry climate, water scarcity, community demands, and environmental constraints in these desert areas, the efficient use of water in mining is being strongly enforced. For this reason, water supply is recognized as one of the limiting factors for the development of new mining projects and for the expansion of the existing ones in these areas. New water supply alternatives, such as sea water desalinization, direct use of sea water, or water recovery from tailings, represent the strategy developed by the mining industry to deal with this growing scarcity. The focus of this paper is the possibility of applying different water supply technologies or a combination of these, implementing improved water management strategies that consider: environmental issues, technical issues, stringent regulatory frameworks, community requests and cost-effective strategies, that result in a reduction of freshwater make-up water requirements for mining (m3 per metric tonnes of treated ore).

1. Introduction

Tailings are usually a very fine mud or powder, left over after ore is crushed and valuable minerals are extracted. Tailings production is immense, since only ounces or pounds of metal are extracted for every tonne of processed ore. Tailings may also contain chemicals used in metallurgical processes as well as other metals and sulphides contained in ore, which need to be considered for safe tailings management. For this reason, most tailings are not inert from a geochemical point of view and must be disposed of with control to care for the environment.
The transport and storage of tailings require relevant environmental management. This residue is generally managed and transported hydraulically using fresh water to tailings storage facilities (TSF), this alternative being cheaper than bulk transportation by conveyor belts, trains or trucks. It is relevant to mention that most of the water used for tailings transportation needs to be recovered for reuse in the metallurgical process [1].
Metal production of copper, silver, gold, lead, zinc, among others, is growing quickly, and part of the increasing water demand can be explained by the expansion of existing mines and new projects being developed. In addition, there is an important increase in copper extraction/production caused by declining copper grades at existing mines. As copper grades decline, more ore needs to be processed in order to produce the same amount of copper metal. The use of water is proportional to the amount of ore that is processed, so it follows that more water is needed to produce the same amount of copper when grades decline. The exploitation of large ore deposits with decreasing grades has led to the use of efficient large equipment for the milling and processing of ore, which enables higher production rates, that, in turn, implies an increase in water demand for the metallurgical process [2].

2. Efficient Water Management in Latin American Mining

In general, ore deposits located in Latin America, where countries with dry climates such as Chile, Peru, Mexico, Argentina, Bolivia have the following characteristics: (i) very low precipitation rates (annual precipitation of 10 mm/year or less), and (ii) high evaporation rates (monthly evaporation rates up to 10 mm/day); resulting in annual average evaporation rates over 2000 mm/year, as in the Atacama desert, where water supply becomes a major challenge [3]. These issues have raised the necessity of an efficient water management plan to transport and manage tailings during the mine lifetime. Other sites in Latin America with mining operations that lie in dry and water scarcity, where the themes of this paper can be applied, are the following areas:
  • Northern Chile—Atacama Desert (Region of Arica, Region of Tarapaca, Region of Antofagasta, and Region of Atacama).
  • Southern Peru—Atacama Desert (Tacna Department, Moquegua Department, Ica Department, and Arequipa Department).
  • Northern Peru—Sechura Desert (Piura Department, and Lambayeque Department).
  • Southern Bolivia—Atacama Desert (Potosí Department, and Oruro Department).
  • Central and Northern Argentine—Sierra y Pampa (Province of Catamarca, Province of La Rioja, Province of San Juan, and Province of Mendoza).
  • Central and Northern México (Chihuahua State, Sonora State, Zacatecas State, Durango State, and Baja California State).
Due to water scarcity in desert areas, the supply of fresh water (make-up) is not available from groundwater and surface courses, then it is necessary to use sea water. In addition, increasing water demand of communities, agriculture and other productive sectors has led to a vulnerability of freshwater resources, resulting in a conflict of needs for water between different water users. Water resources are increasingly affected by a combination of factors such as climate change, which results in the progressive decline of water supply, recharge and infiltration flows in these basins. Also, the productivity of watersheds has been affected dramatically as a result of dry hydrological conditions.
As a consequence, stakeholders have been affected and, in some cases, drinking water resources have been dramatically compromised, resulting in increasing social pressure. Figure 1 and Figure 2 show, as an example, the amount of water consumption in two northern Chile regions registered in 2007 and the consumption projected for the year 2017.
As shown in both figures, the proportion of water consumption in mining and industrial activities tends to increase, whereas in agriculture, livestock and drinking water, consumption rate tends to decrease in both regions.
These studies demonstrate a competition for water use; therefore, it is necessary to implement solutions and implement water management tools to meet the water demands of all stakeholders.

3. Tailings Management Methodologies Description

Engineers, scientists, mine operators, and authorities are working to improve the design and operation of tailings storage facilities (TSFs), focusing on the development of optimal solutions, which considers the following aspects: (i) reliable performance of technologies; (ii) a dynamic and robust TSF water balance (considering site-specific conditions); and (iii) efficient water management with the control of water losses (evaporation and infiltration). If these key issues are successfully implemented, a reduction of water make-up requirements, decrease of negative environmental impacts and an increase of natural water supply for the community will promote sustainable development [5]
Freshwater sources for mining activities must be carefully studied given the environmental impacts and costs for their implementation. Water supply during the operation must have the capacity to grow to provide the necessary supply of fresh water during the entire useful life of the project. Figure 3 and Figure 4 show typical water flows in a mill and thickening plant and tailings disposal facility in a mining project.
In the case of sea water, the different possible locations for the water intake plant at the coast, the requirement or not for desalination, the required pumping station, and the transport pipelines must be analyzed [6]. In the design phase of the desalination and pumping plant, it is important to consider the variability of the required water flow from the ocean. In general, water losses in tailings deposits increase over time due to: (i) increased evaporation area of the pond of clear water, and (ii) increased consolidation of the deposited tailings, which implies higher seepages also involving seasonal variations.
The application of tailings dewatering technologies for increasing tailings water recovery is a relevant step to reduce water losses (resource from freshwater or seawater supplies) caused by evaporation, infiltration and retention at interstitial voids on tailings storage facilities; for this reason, it is necessary to implement new designs in order to make an environmentally friendly tailings management focus on efficiency water use.
Figure 5 shows different dewatering tailings technologies that focus on water recovery and efficient water management:

3.1. Water Recovery from Tailings with Conventional Technologies (WRCT)

In current Chilean and Peruvian large-scale mining in dry climate areas, most typical tailings disposal schemes consist of conventional or slightly thickened at modest levels of tailings solids weight concentration (Cw 48–52%). Conventional TSFs have dams built of coarse fraction of tailings obtained by hydrocyclones, or have slightly thickened tailings deposits with dams built of borrow material. Conventional tailing dams (Figure 6) may have water recoveries as high as 65–75% in very well operated TSFs, which means they have appropriate tailings distribution, good control of the pond (volume and location) and adequate seepage recovery. In conventional dams, water at the settling pond is decanted and by floating pumps, or decant towers, and dam seepages is collected by a drainage system and cutoff trench systems. However, a high seasonal evaporation rate can substantially reduce water recovery from the pond area, and infiltration from the pond in contact with natural soil can produce water losses [7].

3.2. Water Recovery from Tailings with Thickening Technologies (WRTT)

Thickened Tailings Disposal (TTD) technology (Figure 7) requires more background data than conventional tailings disposal. In the conventional approach, the properties of tailings are fixed by the concentrator plant, whereas in a TTD impoundment, the properties of the tailings and their placement are “engineered” to suit the topography of the disposal area [9]. The behavior of tailings in the two approaches is entirely different. In conventional disposal, tailings segregate as they flow and settle out to an essentially flat deposit, whereas in TTD technology, a sloping surface is obtained. The principal difference is that, in TTD technology, tailings are thickened before discharge to a homogeneous heavy consistency that results in laminar non-segregating flow. In this way, TTD produces high water recovery (80 percent of tailings water recovery) and a self-supporting deposit with sloping sides, requiring small dams [10].

3.3. Water Recovery from Tailings with Paste Tailings Technologies (WRPTT)

Paste Tailings Technology has been applied at a small production scale because a limitation of equipment manufacturing ability exists. This method permits obtaining medium make-up water requirement. However, in some cases, there are difficulties in tailings transportation requiring the use of positive displacement pumping, resulting in the highest capital/operating costs [9]. The main advantage of this method is that large dams are not required, only small dams are needed (Figure 8).

3.4. Water Recovery from Tailings with Filtering Technologies (WRFT)

In the last 20 years, many mining projects around the world have applied a tailings disposal technology called filtered dry stacked tailings (Figure 9). This technique produces an unsaturated cake that allows storage of this material without the need to manage large slurry tailings ponds. The application of this technology has accomplished: (i) an increase of water recovery from tailings (90 percent), (ii) reduction of TSF footprint (impacted areas), (iii) decrease in the risk of physical instability, because TSFs are self-supporting structures under compaction (such as dry stacks), and (iv) a better community perception.
The improvements of filtering technologies (pressure and vacuum filtering) in recent years have allowed operational reliability to increase and the development of large capacity filters, reaching in some projects 50,000 metric tonnes per day (mtpd) of filtered tailings [13].

3.5. Water Recovery from Tailings with Hybrid Technologies (WRHT)

The future trend in mining will be the complementary supply of sea water and fresh water, the greater supply being sea water. Along with this, the implementation of dewatering tailings technologies depending on the characteristics of the mineral (grain size, hardness, specific gravity, chemical composition of tailings, etc.), promote a high water recovery. An alternative process to obtain filtered tailings consists of the recovery of the coarse fraction of tailings (cycloned tailings sand) through two cycloning stages, followed by a drainage stage in dewatering vibratory screens to reduce tailings moisture and turn tailings into a paste that can easily be transported to an adjoining dumping facility (Cacciuttolo et al., 2014). On the other hand, the Sand Slimes Split (SSSTT) method is a known tailings technology. SSSTT is a combination of the conventional cyclone tailings classification and thickening, a variant of the construction of a TSF dam using tailings sand. The primary aspect of SSSTT is that the total tailings are separated to produce two streams: (1) “underflow” corresponding to the tailings coarse fraction (sand); and (2) “overflow” corresponding to the fine tailings fraction (slimes). These streams are conveyed to two independent sites: (i) a Sand Stack Facility (SASF) for the coarse fraction of tailings (Figure 10); and (ii) a Slimes Storage Facility (SLSF) for the fine fraction of tailings, which is thickened before depositing (Figure 11). The main benefit of this technology is the increase of the total water recovery by managing different particle size distribution of tailings [14,15,16,17].

4. Water Recovery Performance Tailings Management Technology Comparison

In recent years, the improvements in tailings dewatering technologies (thickening and filtering) have allowed an increase in water recovery. These technologies have been successfully applied for production rates up to 25,000 mtpd. There is still a need for more reliable equipment for the thickening and filtering processes at large-scale, focused tailings water recovery and reuse in mining processing.
Studies, operational experiences, and TSF water balances performed in the last decades show that make-up water requirement for projects without slimes thickening is in the range of 0.35–0.70 m3/t (Conventional Tailings Technology), while make-up water requirement for slimes thickening (SSSTT) is in the range of 0.30–0.40 m3/t.
Table 1 shows a comparison between different tailings management technologies, considering water make-up requirements (TSF water losses). Data come from some projects located in extremely dry areas of Chile and Peru.
Figure 12 shows a comparison between different tailings management technologies, considering make-up water requirements and water recovery results at some projects with desert areas.
Water losses at TSFs come from water retained in deposited tailings and in the evaporation from beaches formed at the TSF. To reduce these losses, new management technologies have been developed, which seek to maximize the reclamation of water before tailings are discharged to the TSF, by cycloning, thickening, and/or filtering tailings. Improvements in conventional, thickened, paste and filtered tailings disposal technologies need to be managed to increase water recovery and decrease water make-up (fresh water) in mining operations. These challenges have been met during the past decade at copper mining.
Table 2 shows a comparative analysis with water recovery quantities obtained with different dewatering tailings technologies.

5. Case Study of Evaluation Dewatered Tailings Methodologies and Different Sources of Water at Large-Scale Mining Sites

A case study is presented, based on a typical large copper mine that processes 100,000 mtpd, with 20 years’ mine life and current deposition of conventional slurry tailings with 50% of solid content by weight. Water recovery from the TSF is very low, mainly because of a high evaporation rate in the extreme dry area and infiltration. Different tailings management alternatives need to be evaluated to select a cost-effective solution, considering fresh water and sea water supply options, focused on obtaining a high water recovery from tailings and the proper disposal of tailings. Table 3 presents the parameters considered for Alternatives Comparison.
Considering this comparative analysis, Figure 13 shows the graphical view of a mining project with the use of sea water for the metallurgical process and tailings management.
Table 4 presents the results of total cost of comparative analysis of alternatives of this study case.
Costs are evaluated on the basis of water usage relative to the production efficiency of the mine. In copper ore deposits where the quality of ore grade is low, the cost of water used per unit weight of metal obtained is high. Therefore, mining companies have to assess the cost effectiveness of using brackish or desalinated water. To avoid the costs of desalination or brackish water use, mining companies are attempting to improve the efficiency of their water use in operations, by reducing water losses due to infiltration, evaporation or effluent generation.
Because average copper grades of copper sulphide ores in Chile and Peru have decreased from 1.18% to 0.90% over the period of the last 2 decades, greater consumption of water, energy and chemical reagents is required to efficiently process low-grade copper sulphide ores. In particular, the consumption of collectors, frothers and modifiers in froth flotation is increasing because higher amounts of low-copper grade ore are processed [39]. For example, the average concentration of collectors and frothers being used in 2012 was 50 g/t ore and 30 g/t ore, respectively. These concentrations correspond to 26,243 tonnes of collectors and 15,745 tonnes of frothers per year [39].
On the other hand, new trends consider the reprocessing of historic tailings that can have important economic and environmental benefits, as these materials have already been mined and ground, reducing the operating costs and the energy required to reprocess them. The reprocessing of these old tailings, however, entails considerable challenges, such as processing fine particles containing complex ores and gangues. The reprocessing methodologies, therefore, vary depending on the requirements of each TSF [40,41].
Technologies available to treat or reprocess copper mine tailings fall into the three categories below.
  • Flotation/concentration: The copper is separated from the gang material using froth flotation collected and dewatered using thickening and filtration.
  • Leach hydro-metallurgical: Copper mine tailings are leached using sulfuric acid (or other agents) and the pregnant Leach solution is sent to a solvent extraction—electro winning (SXEW) circuit.
  • Biological treatment: Bacterial action is used in mine tailings to transfer the copper from the solid matrix to a solution which subsequently is sent to SXEW.
Figure 14 shows the graphical results of the 8 alternatives and a comparative analysis of costs estimate.
The results indicate that fresh water supply use, given the specific characteristics of this large-scale mining production study case, thickened tailings technology is the most cost-effective alternative. The second options, not too far from the first place, are conventional tailings technology and hybrid tailings technology. Competitiveness of these alternatives against thickened tailings technology will depend heavily on the unit cost of fresh water and the efficient management performance to control water loss.
On the other hand, filtered tailings technology is the less cost-effective alternative with the use of fresh water. However, when the cost of sea water is incorporated, the situation changes and the technology becomes the most cost-effective alternative. Finally, depending on the characteristics of the project being evaluated (distance/level from the coast, cost of energy, equipment cost and reliability, etc.), the filtered tailings alternative could become the most feasible alternative.
Although the development of thickening and filtering technologies has advanced significantly in the last years, more investigations/studies need to be conducted to understand their behavior, focusing on obtaining good performance at a larger production scale with different tailings particle size distributions and mineralogy. This shows the high variability of the characteristics of treated ore in the grinding and flotation process in the metallurgical plants.

6. New Mine Operation Cases—Greenfield Projects

Greenfield projects are defined like new mining projects that are starting operations, where greenfield projects have additional complications because of the limited knowledge of project conditions. For example, early ore samples may not appropriately reflect the final source of tailings. For this reason, in a greenfield project evaluation, it is necessary to include a risk analysis of the water use and the technologies considered for tailings management. These projects, in particular, would do well to consider options and experiences from existing projects at the same production scale. Community, environmental and social issues should be given significant consideration.
The main economic and environmental drivers to consider the conversion to thickened/paste or tailings/filter cake deposition systems are:
  • Major increase in water losses from the tailings in conventional technologies (slurry tailings) at extreme dry climates.
  • Eliminate high capital/operation costs for new water sources (sea water desalination) to maintain and/or increase production.
  • Substantial capital/operation cost reduction in the TSF as compared to conventional slurry tailings disposal.
  • It is important to note that for some specific cases, extracting water from the tailings has the potential to be a better option than sourcing water make-up from the sea.
  • The main economic and/or environmental drivers to consider a seawater supply are:
  • Potential depletion of freshwater make-up, and/or the need of a major increase in water recovery from tailings.
  • Sustainable use of water, promoting economic, environmental and quality life development of stakeholders in the region.

7. Expansion Mine Operation Cases—Brownfield Projects

Brownfield projects are defined like old mining projects that are continuing or expanding their operation, where brownfield Projects are less risky, as ore composition from the mine is better understood and tailings management methodology is well known, but since most ore resources have been largely exploited, the economical reward is decreasing. The exploitation of a low-grade deposit requires extracting a greater quantity of ore and using more water, to obtain a competitive advantage in the market, which is why the concentration process and use of water resources requires a higher efficiency.
Engineers and mining operators have completed studies for 15 years on highly dewatered tailings disposal methods for a number of large-scale mining operations/projects in northern Chile. The lesson learned is that there are potential cost savings motivating change from conventional slurry tailings disposal systems to alternative highly dewatered tailings disposal systems in existing operations [42].
Make-up water for mining operations has historically been obtained from surface streams and underground water located in the Andes Mountains within environmentally sensitive areas. The majority of these water sources are currently considered to be exploited to their limits, whilst some are nearing depletion or will have to be closed down to limit environmental damage. Mining operations in places with water scarcity that have expansion plans are now turning their attention to the sea as a source of water for their future water needs [43], for this please see Figure 15. Table 5 presents mining operations that have taken the decision to supply their metallurgical processes and tailings management with sea water.

8. Conclusions

Water is a resource requested by many stakeholders such as population, industry, agriculture, among others. Inadequate control of freshwater distribution and excessive use of fresh water for industrial purposes may cause a shortage of water for local population in northern Chile and southern Peru in the future.
In this context, mining companies can make a significant contribution to society in terms of water management, with focus on sustainable development and long-term vision. Efficient use of water for industrial purposes should recover as much water as possible, reducing possible losses to the environment, and must be distributed properly between users, according to their demands and requirements with the compliance of local quality standards.
While industrial activities generate economical value and allow businesses transacting goods and services, this activity should also generate social value by improving the quality of life of people, mitigate negative impacts and promote sustainable development. Industrial and wastewater from mining activities should be recycled instead of increasing freshwater make-up. Also, the use of seawater and wastewater reuse should be considered.
In many cases, the ability of a mine to operate is contingent on having sufficient water make-up to compensate for the losses incurred during the operations, which are mostly account in the TSF. For this reason, considering water recovery measures in the design of TSF and developing an accurate water balance model are important factors for the success of the project.
A water management plan can provide an improvement of water recovery from tailings for its reuse in metallurgical process, hydraulic transport of tailings/concentrate and mine site reclamation. The implementation of a good water management plan can significantly reduce water make-up (fresh water) requirements and costs in the long term.
Taking into account the reasons announced above in this article, economic (cost savings) and environmental (less water use and community approval) drivers exist in desert areas of Chile and Peru to: (i) consider the conversion to thickened/paste or tailings/filter cake disposal technology, and (ii) consider the supply of sea water for mining processes. These aspects will be the new design and operation trends of Greenfield and Brownfield mining projects.
The adequate water management is the major challenge for mining, agriculture, industries, population, and authorities nowadays. We have not solved all our difficulties yet, and there are many interesting solutions waiting to be found.

Author Contributions

Conceptualization, C.C. and F.V.; formal analysis, C.C.; investigation, C.C.; resources, F.V.; writing—original draft preparation, C.C.; writing—review and editing, C.C.; visualization, C.C.; supervision, F.V. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Data Availability Statement

The data presented in this study are available on request from the corresponding author.

Acknowledgments

The authors of this paper wish to express their appreciation to Fernando Valenzuela for reviewing and assisting with key contributions to create this article.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Barrera, S.; Arredondo, M.; Madariaga, P.; Scognamillo, C. Tailings management a simple way to increase water reclaim. In Proceedings of the 11th International Conference on Tailings and Mine Waste, Vail, CO, USA, 10–13 October 2004; A.A. Balkema: Rotterdam, The Netherlands, 2004; pp. 39–44. [Google Scholar]
  2. Cacciuttolo, C.; Scognamillo, C. Improving Water Recovery with Different Tailings Management Technologies. In Proceedings of the 4th International Congress on Water Management in Mining WIM 2014, Viña del Mar, Chile, 10–13 May 2014. [Google Scholar]
  3. Wels, C.; MacG, A.R. Water recovery for Pampa Pabellon tailings impoundment, Collahuasi, Chile. In Proceedings of the 11th International Conference on Tailings and Mine Waste, Vail, CO, USA, 10–13 October 2004; A.A. Balkema: Rotterdam, The Netherlands, 2004; pp. 77–88. [Google Scholar]
  4. Samad, M.A.; Singh, S. Mine Water Management Strategies in Dry Areas of Chile. In Proceedings of the 1st International Conference on Mine Water Solutions in Extreme Environments, Lima, Peru, 15–17 April 2013. [Google Scholar]
  5. Tabra, K.; Lange, S. Active Treatment of Tailings Seepage with Focus on Sulphate and Manganese Removal. In Proceedings of the 2nd International Seminar on Tailings Management TAILINGS 2014, Antofagasta, Chile, 6–8 August 2014. [Google Scholar]
  6. Tabra, K.; Gaete, O. Ways to Deal with Mine/Plant Effluent Residues: A roadmap process. In Proceedings of the 142th SME Annual Meeting, Denver, CO, USA, 24–27 February 2013. [Google Scholar]
  7. Valenzuela, L. Design, construction, operation and the effect of fines content and permeability on the seismic performance of tailings sand dams in Chile. Obras Y Proy. 2016, 19, 6–22. [Google Scholar] [CrossRef] [Green Version]
  8. FCX (Freeport McMoran). 2018 Working toward Sustainable Development Report. Available online: https://www.fcx.com/sites/fcx/files/documents/sustainability/wtsd_2018.pdf (accessed on 10 April 2022).
  9. Schoenbrunn, F. Dewatering to higher densities. In Proceedings of the 14th International Seminar on Paste and Thickened Tailings, Perth, Australia, 5–7 April 2011; Jewell, R.J., Fourie, A.B., Eds.; ACG: Perth, Australia, 2011; pp. 19–24. [Google Scholar]
  10. Robinsky, E.I. Thickened Tailings Disposal in the Mining Industry; E.I. Robinsky Associates Ltd.: Lydia Court, TO, Canada, 1999. [Google Scholar]
  11. Ministerio de Minería. Plan Nacional de Depósitos de Relaves para una Minería Sostenible. 2019. Available online: https://www.minmineria.cl/media/2021/05/Plan_Nacional_de_Despositos_de_Relaves_para_una_Mineria_Sostenible_2021.pdf (accessed on 1 April 2022).
  12. Cacciuttolo, C.; Holgado, A. Management of Paste Tailings in Chile: A Review of Practical Experience and Environmental Acceptance. In Proceedings of the 19th International Seminar on Paste and Thickened Tailings Paste, Santiago, Chile, 3–6 July 2016. [Google Scholar]
  13. Cacciuttolo, C.; Barrera, S.; Caldwell, J.; Vargas, W. Filtered Dry Stacked Tailings: Developments and New Trends. In Proceedings of the 2nd International Seminar on Tailings Management, Antofagasta, Chile, 15–17 August 2014. [Google Scholar]
  14. Caldwell. Presentation Tailings Facility Failures in 2014 and an Update on Failure Statistics. Available online: https://www.riskope.com/wp-content/uploads/2015/10/Tailings-Facility-Failures-in-2014-and-an-Update-on-Failure-Statistics.pdf (accessed on 5 December 2012).
  15. Barrera, S.; Riveros, C. Caserones: Option of tailings classifying to improve water reclaim. In Proceedings of the 12th International Seminar on Paste and Thickened Tailings, Viña Del Mar, Chile, 21–24 April 2009. [Google Scholar]
  16. Lyell, K.A.; Copeland, A.M.; Blight, G.E. Alternatives to paste disposal with lower water consumption. In Proceedings of the 11th International Seminar on Paste and Thickened Tailings, Kasane, Botswana, 5–8 May 2008; Fourie, A.B., Jewell, R.J., Slatter, P., Paterson, A., Eds.; Australian Center of Geomechanics: Perth, Australia, 2008; pp. 171–178. [Google Scholar]
  17. Wels, C.; Caldwell, J. Challenges in tailings water balance analysis—Make-up water, seepage and consolidation. In Proceedings of the 1st Mine Water Solutions in Extreme Environments Conference, Lima, Peru, 15–17 April 2013. [Google Scholar]
  18. Consejo Minero. Plataforma Online de Relaves Mineros. Available online: https://consejominero.cl/comunicaciones/plataforma-de-relaves/ (accessed on 2 April 2022).
  19. Wels, C.; MacG, A.R. Conceptual Model for Estimating Water Recovery in Tailings Impoundments. In Proceedings of the 10th International Conference on Tailings and Mine Waste, Vail, CO, USA, 10–13 October 2004. [Google Scholar]
  20. Barrientos, S. Design, operation and control of the Mauro tailings dam. In Proceedings of the Plenary Presentation at 1st International Seminar on Tailings Management, Santiago, Chile, 1–3 September 2013. [Google Scholar]
  21. Mineria Los Pelambres. Presentation about El Mauro Tailings Storage Facility. Available online: https://www.antofagasta.co.uk/investors/news/2019/statement-on-the-stability-of-our-tailings-dams-and-deposits/ (accessed on 7 April 2022).
  22. Ecometales. Presentation about Candelaria Mine and Tailings Management. Available online: https://www.ecometales.cl/ecometales/site/docs/20191111/20191111114704/7_lundin_mining_candelara.pdf (accessed on 6 April 2022).
  23. Sotil, A.; Soto, V.; Brouwer, K. Reducing Long Term Risk at Candelaria Tailings Storage Facility. In Proceedings of the Tailings and Mine Waste 2020, Vancouver, Canada, 15–18 November 2020; Available online: https://www.knightpiesold.com/en/news/publications/reducing-long-term-risk-at-the-candelaria-tailings-storage-facility/ (accessed on 4 April 2022).
  24. Teck. Tailings Management of Quebrada Blanca Phase 2 Mining Project. Available online: https://www.teck.com/media/Connect-vol-25-ES.pdf (accessed on 23 April 2022).
  25. Chambers, B.; Howard, P.; Pottie, J.; Murray, L.; Burgess, A. Water recovery from a mine in the Atacama Desert. In Proceedings of the 10th Water in Mining Conference, Brisbane, Australia, 27–28 October 2003. [Google Scholar]
  26. Thiele, C.; Parraguez, L. Minera Esperanza Presentation. In Proceedings of the 3rd Paste Tailings Seminar, RELPAS, Amsterdam, Netherlands, 26 October 2011; Available online: https://issuu.com/revistamch/docs/mch_358 (accessed on 23 December 2011).
  27. Engels, J.; Gonzalez, H.; Aedo, G.; Mcphail, G. Implementation of Spigot Discharge Systems for High-Density Tailings at Sierra Gorda Sociedad Contractual Minera, Chile. Paste 2018; Jewell, R.J., Fourie, A.B., Eds.; Australian Centre for Geomechanics: Perth, Australia, 2018; ISBN 978-0-9924810-8-7. [Google Scholar]
  28. Engels, J.; Gonzalez, H.; Aedo, G.; McPhail, G.I. Implementation of spigot discharge systems for high-density tailings at Sierra Gorda Sociedad Contractual Minera, Chile. Available online: https://www.photosat.ca/wp-content/uploads/2019/09/PhotoSat-Advances-in-Tailings-surveying-using-optical-satellites-Report.pdf (accessed on 25 April 2022).
  29. Pino, R. Presentation Depositacion de Relaves Espesados en Proyecto Cerro Negro Norte. In Proceedings of the 5th Paste Tailings Seminar, RELPAS, Santiago, Chile. Available online: http://www.plataformacaldera.cl/biblioteca/589/articles-64617_documento.pdf (accessed on 2 December 2013).
  30. Barrera, S.; Cacciuttolo, C.; Caldwell, J. Reassessment of best available tailings management practices. Tailings Mine Waste Int. Conf. 2015. [Google Scholar] [CrossRef]
  31. Lara, J.L.; Pornillos, E.; Loayza, C. The application of highly dewatered tailings in the design of tailings storage facilities—Experience in Mining Projects in Peru. In Proceedings of the 16th International Conference on Tailings and Mine Waste, Keytone, SD, USA, 14–17 October 2012. [Google Scholar]
  32. Lara, J.L.; León, E. Design and Operational Experience of the Cerro Lindo Filtered Tailings Deposit. In Proceedings of the Paste and Thickened Tailings 2011 Seminar, Perth, Australia, 5–7 April 2011. [Google Scholar]
  33. Pizarro, N. SCMLCC Presentation. In Proceedings of the 1st Mining Symposium, ATACAMAMIN, Copiapo, Chile, 20–23 May 2012. [Google Scholar]
  34. Obermeyer, C.; Enriquez, J.; Alexieva, T. Enviable water recovery in a desert environment: A case study. In Proceedings of the 1st International Conference on Mine Water Solutions in Extreme Environments, Lima, Peru, 15–17 April 2013. [Google Scholar]
  35. Obermeyer, J. Cerro Verde Mine Tailings Storage Facility Webinar. Available online: https://www.stantec.com/en/ideas/topic/energy-resources/webinar-recording-cerro-verde-mine-tailings-storage-facility (accessed on 12 April 2022).
  36. Stantec. Cerro Verde Mine Tailings Storage Facility Webinar. 2022. Available online: https://www.youtube.com/watch?v=V2bULqEo3j0 (accessed on 11 April 2022).
  37. Serpa, B.; Walqui, H.B. Tailings disposal at Quebrada Honda Toquepala. In Proceedings of the 11th International Seminar on Paste and Thickened Tailings, Kasane, Botswana, 5–9 May 2008; Fourie, A.B., Jewell, R.J., Slatter, P., Paterson, A., Eds.; Australian Center of Geomechanics: Perth, Australia, 2008. [Google Scholar]
  38. Quellaveco. El Proyecto: Así se construye Quellaveco. Quellaveco Webpage. 2022. Available online: https://peru.angloamerican.com/es-es/quellaveco (accessed on 10 April 2022).
  39. Reyes-Bozo, L.; Godoy-Faúndez, A.; Herrera-Urbina, R.; Higueras, P.; Salazar, J.L.; Valdés-González, H.; Vyhmeister, E.; Antizar-Ladislao, B. Greening Chilean copper mining operations through industrial ecology strategies. J. Clean. Prod. 2014, 84, 671–679. [Google Scholar] [CrossRef] [Green Version]
  40. Mesa, D.; Barriga, D.; Berríos, P.; Rodríguez, E.; Amelunxen, R. Reprocessing historic tailings—Three Chilean case studies. In Proceedings of the Procemin Geomet 2020, 16th International Mineral Processing Conference, Santiago, Chile, 25–27 November 2020. [Google Scholar]
  41. Edraki, M.; Baumgartl, T.; Manlapig, E.; Bradshaw, D.; Franks, D.M.; Moran, C.J. Designing mine tailings for better environmental, social and economic outcomes: A review of alternative approaches. J. Clean. Prod. 2014, 84, 411–420. [Google Scholar] [CrossRef]
  42. Araya, N.; Ramirez, Y.; Cisternas, L.; Kraslawsky, A. Use of real options to enhance water-energy nexus in mine tailings management. Appl. Energy 2021, 303, 117626. [Google Scholar] [CrossRef]
  43. Avila, P.; Brantes, R.; Perez, P. Sin Agua No hay Minería: Impacto de la Desalinización en la Posición Competitiva de la Industria Chilena de Cobre. In Proceedings of the 2nd International Seminar on Desalination and Water Reuse, Antofagasta, Chile, 2–4 November 2010. [Google Scholar]
  44. Consejo Minero. Políticas de Sustentabilidad y Relación con las Comunidades en el Uso del Agua en la Minería. 2022. Available online: https://consejominero.cl/ (accessed on 12 April 2022).
  45. Cochilco. Proyección Demanda de Agua Fresca en la Minería del Cobre, 2013–2021. 2013. Available online: https://www.cochilco.cl/Listado%20Temtico/2020%2012%2024%20Proyeccion%20agua%20mineria%20del%20cobre%202020-2031_v1.0.pdf (accessed on 10 April 2014).
  46. Pincock, P.; Allen, K.; Holt, G. Technical Report for the Sierra Gorda Project, Chile. Available online: https://minedocs.com/20/Sierra_Gorda_Project_Technical_Report_2907887_06082011.pdf (accessed on 25 April 2022).
  47. SEA (Servicio de Evaluacion Ambiental). Environmental Impact Assesment of Quebrada Blanca Phase 2 Mining Project. Available online: https://seia.sea.gob.cl/documentos/documento.php?idDocumento=2131794108 (accessed on 23 April 2022).
  48. Codelco. Proyecto RT Sulfuros. 2012. Available online: https://www.codelco.com/prontus_codelco/site/edic/base/port/rt_sulfuros.html (accessed on 18 September 2012).
  49. Lara, J.L. Presentacion de relaves espesados y filtrados en Perú, Insituto de Ingenieros de Minas, Jueves Minero. Available online: https://www.youtube.com/watch?v=0vcYR2gSPjk (accessed on 12 April 2022).
  50. MDO (Mining Data Online). Bayovar 12 Phosphate Project. 2022. Available online: https://miningdataonline.com/property/3299/Bayovar-12-Project.aspx (accessed on 10 April 2022).
  51. Shougang. Video Proceso Expansion Proyecto Shougang. 2022. Available online: https://www.youtube.com/watch?v=0QwRKwhAalc (accessed on 5 April 2022).
  52. Marcobre. Modificación del EIAD del Proyecto Mina Justa. 2022. Available online: https://www.marcobre.com/wp-content/uploads/2019/08/Resumen-Ejecutivo-del-EIA-Semi-detallado-3era-Modificaci%C3%B3n-del-Proyecto-de-Exploraci%C3%B3n-Mina-Justa-2013.pdf (accessed on 10 April 2022).
Figure 1. Water consumption in Antofagasta Region (Region II) of Chile [4].
Figure 1. Water consumption in Antofagasta Region (Region II) of Chile [4].
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Figure 2. Water consumption in the Atacama Region (Region III) of Chile [4].
Figure 2. Water consumption in the Atacama Region (Region III) of Chile [4].
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Figure 3. Typical flows into and out of a mill and thickening mining plant.
Figure 3. Typical flows into and out of a mill and thickening mining plant.
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Figure 4. Typical Flows into and out of a mine tailings disposal facility.
Figure 4. Typical Flows into and out of a mine tailings disposal facility.
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Figure 5. Dewatering Tailings Technologies—Efficient Water Management.
Figure 5. Dewatering Tailings Technologies—Efficient Water Management.
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Figure 6. Conventional Tailings Technology—Quebrada Enlozada TSF Cerro Verde Mine Peru [8].
Figure 6. Conventional Tailings Technology—Quebrada Enlozada TSF Cerro Verde Mine Peru [8].
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Figure 7. Thickened Tailings Technology—Esperanza TSF Centinela Mine Chile [11].
Figure 7. Thickened Tailings Technology—Esperanza TSF Centinela Mine Chile [11].
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Figure 8. Paste Tailings Technology—Paste Tailings Demo Plant at Collahuasi Mine Chile [12].
Figure 8. Paste Tailings Technology—Paste Tailings Demo Plant at Collahuasi Mine Chile [12].
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Figure 9. Filtered Tailings Technology—Tailings Filters at Mantos Blancos Mine Chile [11].
Figure 9. Filtered Tailings Technology—Tailings Filters at Mantos Blancos Mine Chile [11].
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Figure 10. Sand Stack TSF (Cycloned Sand Tailings) SSSTT—Caserones Mine, Chile [18].
Figure 10. Sand Stack TSF (Cycloned Sand Tailings) SSSTT—Caserones Mine, Chile [18].
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Figure 11. Slimes Storage Facility (Cycloned Fine Tailings) SSSTT—Caserones Mine, Chile [18].
Figure 11. Slimes Storage Facility (Cycloned Fine Tailings) SSSTT—Caserones Mine, Chile [18].
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Figure 12. Make-up tailings management technologies comparison of performance.
Figure 12. Make-up tailings management technologies comparison of performance.
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Figure 13. Schematic view of mining project with desalinated water use.
Figure 13. Schematic view of mining project with desalinated water use.
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Figure 14. Results of Cost Estimate for Tailings Management Alternatives.
Figure 14. Results of Cost Estimate for Tailings Management Alternatives.
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Figure 15. Escondida Mine Sea Water Desalination Plant, Chile [44].
Figure 15. Escondida Mine Sea Water Desalination Plant, Chile [44].
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Table 1. Tailings management methodologies and average water make-up (TSF water losses).
Table 1. Tailings management methodologies and average water make-up (TSF water losses).
Tailings Management MethodologyTailings Storage Facility NameCountryTSF Disposal and Water Management ParametersReference
Production Rate (mtpd)PSD d50 (µm)Solids Content Cw (%)Average Make-Up (m3/mt)
FWS—WRCTPampa Pabellon TSFChile170,0005252 (TT)0.70[19]
FWS—WRCTTalabre TSFChile180,0007055 (TT)0.64[19]
FWS—WRCTLos Quillayes TSFChile115,0003640 (SL)0.35[20]
FWS—WRCTMauro TSFChile205,0003640 (SL)0.35[21]
FWS—WRCTCandelaria TSFChile75,0006551 (TT)0.34[22,23]
FWS—WRCTCandelaria (Los Diques TSF)Chile75,0006551 (TT)0.34[22,23]
FWS—WRCTCarmen de Andacollo TSFChile55,0007053 (TT)0.44[24]
SWS—WRCTLaguna Seca TSFChile370,0006550 (TT)0.66[25]
SWS—WRTTEsperanza (Centinela TSF)Chile95,0004565 (TT)0.50[26]
SWS—WRTTSierra Gorda TSFChile110,0004060 (TT)0.50[27,28]
SWS—WRTTCerro Negro Norte TSFChile20,0007565 (TT)0.45[29]
FWS—WRPTTLas Cenizas (Chinchorro TSF)Chile25004465 (TT)0.39[30]
FWS—WRPTTENAMI (Delta Plant TSF)Chile20002560 (TT)0.48[30]
FWS—WRPTTCoemin TSF Chile80005060 (TT)0.42[30]
FWS—WRPTTAlhue TSFChile30005565 (TT)0.40[30]
FWS—WRFTLa Coipa TSFChile20,0006880 (TT)0.22[31]
FWS—WRFTEl Peñon TSFChile30006284 (TT)0.20[32]
FWS—WRFTMantos Verde TSFChile12,0005782 (TT)0.23[32]
FWS—WRHTMantos Blancos TSFChile12,0008682 (TT)0.28[31]
FWS—WRHTCaserones (La Brea/Sand TSF)Chile90,0007460 (TT)0.37[15,33]
FWS—WRFTCerro Lindo TSFPeru70006588 (SL)0.20[32]
FWS—WRCTQuebrada Enlozada TSFPeru120,0004540 (SL)0.38[34,35]
FWS—WRCTQuebrada Linga TSFPeru240,0004540 (SL)0.38[35,36]
FWS—WRCTQuebrada Honda TSFPeru150,0007537 (SL)0.62[37]
FWS—WRCTQuebrada Cortadera TSFPeru127,5007545 (TT)0.40[38]
Note: The following terms mean: TT: Total Tailings, SL: Slimes (fine particle size distribution of total tailings), FWS: Fresh Water Supply and SWS: Sea Water Supply.
Table 2. Water Recovery Comparison between Tailings Management Methodologies.
Table 2. Water Recovery Comparison between Tailings Management Methodologies.
DescriptionUnitConventional Tailings
Management
Thickened Tailings
Management
Hybrid Tailings ManagementFiltered Tailings
Management
Tailings Productionmtpd100,000100,000100,000100,000
Cw before Thickening%28282828
Water on Conventional TailingsL/s2976297629762976
Cw after Thickening%506070 (*)80
Water on Dewatered TailingsL/s1157772496289
Water Recovery from ThickenersL/s1819220524802687
Water Recovery from TSFL/s38225516495
Total Water RecoveryL/s2201245926442782
Water Recovery Efficiency%74838993
Note: The following terms mean: Cw: Tailings solid content by weight (%). (*): 70 % signifies a mean target Cw value, considering dewatering tailings technologies applied.
Table 3. Parameters considered for Alternatives Comparison.
Table 3. Parameters considered for Alternatives Comparison.
ParametersValueUnit
Tailings Production Rate100,000mtpd
Sea-Concentrator Plant Distance150km
Sea-Concentrator Plant Difference of Level2000m.a.s.l.
Mine Lifetime20years
Discount Rate for Cost Estimate10%
Table 4. Comparative Analysis—Tailings Management Methodology Alternatives Cost Estimate.
Table 4. Comparative Analysis—Tailings Management Methodology Alternatives Cost Estimate.
Tailings Management MethodologyConventional Technology
Cw 50%
Thickened Technology
Cw 60%
Hybrid Technology
Cw 70%
Filtered Technology
Cw 80%
(a)
Tailings Disposal
Case 1Case 2Case 3Case 4Case 5Case 6Case 7Case 8
CAPEX, million US$225225150150250250450450
Total SUSTAINING Cost, million US$1001002002001251255050
OPEX, million US$ per year1515252535355050
Make-up water flow rate, L/s691691432432346346173173
Tailings Disposal Cost, US$/t0.90.91.21.21.51.52.12.1
(b)
Make-Up Water Supply
Case 1Case 2Case 3Case 4Case 5Case 6Case 7Case 8
CAPEX, million US$5075025650155005250
Make-up water, m3/t0.80.80.50.50.40.40.20.2
Water Cost, US$/m3 (Fresh Water)1.7-1.7-1.7-1.7-
Water Cost, US$/m3 (Sea Water)-4.0-4.0-4.0-4.0
OPEX, million US$ per year (Fresh Water)50-31-25-12-
OPEX, million US$ per year (Sea Water)-117-73-58-29
Make-Up Water Cost US$/t (Fresh Water)1.4 0.9 0.7 0.3-
Make-Up Water Cost US$/t (Sea Water)-4.2-2.9-2.3-1.1
(c)
Integral Tailings/Water Management
Case 1Case 2Case 3Case 4Case 5Case 6Case 7Case 8
Unit Cost, US$/t2.35.12.04.12.23.82.43.2
Net Present Cost, Million US$925 2197 852 1834 899 1670 934 1424
Note: (1) Par number cases considers fresh water supply, and impair number cases consider sea water supply. (2) Capex considers the following items: process equipment, pipelines/conveyors, embankment, direct/indirect costs, owner costs, and contingency. (3) Sustaining Costs considers the following items: deferred equipment, pipelines/conveyors and installations. (4) Opex considers the following items: power, flocculant, labor, maintenance, and earth-moving equipment.
Table 5. Sea water use at mine operations for metallurgical and tailings process.
Table 5. Sea water use at mine operations for metallurgical and tailings process.
Mine Operation NameCountryTailings Production (mtpd)Sea Water Pumping Capacity (L/s)Seawater Supply (%)StatusReference
EscondidaChile370,000380075In Operation[45]
Esperanza (Centinela)Chile95,0001500100In Operation[45]
CandelariaChile75,00050085In Operation[45]
Cerro Negro NorteChile20,000200100In Operation[45]
Sierra GordaChile100,0001315100In Operation[45,46]
Quebrada Blanca IIChile140,000850100In Operation[47]
RT SulfurosChile200,0002000100Project[48]
Cerro LindoPeru15,000120100In Operation[49]
BayovarPeru15,000450100In Operation[50]
ShougangPeru20,000231100In Operation[51]
Mina Justa (Marcobre)Peru15,000250100In Operation[52]
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Cacciuttolo, C.; Valenzuela, F. Efficient Use of Water in Tailings Management: New Technologies and Environmental Strategies for the Future of Mining. Water 2022, 14, 1741. https://doi.org/10.3390/w14111741

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Cacciuttolo C, Valenzuela F. Efficient Use of Water in Tailings Management: New Technologies and Environmental Strategies for the Future of Mining. Water. 2022; 14(11):1741. https://doi.org/10.3390/w14111741

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Cacciuttolo, Carlos, and Fernando Valenzuela. 2022. "Efficient Use of Water in Tailings Management: New Technologies and Environmental Strategies for the Future of Mining" Water 14, no. 11: 1741. https://doi.org/10.3390/w14111741

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