In the long term, primary and secondary supply of refined copper satisfies demand. Numerous models exist to explain and predict demand and secondary supply; however, the projection of primary supply relies mostly on detailed knowledge of potential mining projects and on existing ore reserves and resources. Much discussion has occurred historically regarding the availability of resources and reserves for the future. Chile, being the largest copper producer, also has the largest reserves in the world; therefore, it retains its potential to be a key player in future supply. This article explores some of the most relevant resource and technological challenges that may emerge with an accelerated development of brownfield and greenfield copper mining projects in Chile through 2035, without considering economic, regulatory, and environmental constraints. A “Full Scenario” was created to accommodate these conditions and restrictions. It includes estimates of future ore reserves, copper production, plant capacity, ore grades, energy and water consumption, greenhouse gas (GHG) emissions, and generation of tailings. Maximum production would exceed 10 million tons of contained copper from 2027 to 2030, with a resulting decrease of ore grades and the growth of energy and water consumption. The growth of indirect GHG emissions through 2035 is estimated at 18.4% less than copper production growth, because all new electric energy for this scenario would be based on renewable energy. Also, all new water used by 38 out of the 42 mining projects considered would be seawater, and some of the continental water used in 2019 would cease to be used in mining.
While there are numerous theoretical models regarding future copper refined demand (Paley Commission 1952; Meadows et al. 1972; Fisher et al. 1972; Tan 1987; Vial 1988; Ayres et al. 2002; Valencia 2005; Elshkaki et al. 2016; Schipper et al. 2018) and of secondary refined production (Fisher et al. 1972; Slade 1980; Tan 1987; Vial 1988; Valencia 2005; Gomez et al. 2007; Fu et al. 2017), very few primary supply theoretical models were found in the literature (Fisher et al. 1972; Tan 1987; Vial 1988). The production function (Cobb and Douglas 1928) was applied in these models to estimate primary production, but the results proved too general in order to guide public institutions and companies as to what greenfield and brownfield projects would be developed first in the future. Future refined production forecast methods, therefore, were developed based on detailed reserve, cost, production capacity, and commissioning date knowledge of individual projects available globally, whose existence had been reported by mining and exploration companies (Wood Mackenzie 2018; Cochilco 2019a).
The most traditional forecast method is adopting the expansion plans made public by mining companies. This method is used by the Chilean Copper Commission (Cochilco) in some of its reports (Cochilco 2019a). A second method is employed by most expert commodity companies and agencies, including Cochilco (Cochilco 2019b) in some cases; it consists in modifying both the time for commissioning, and the throughput announced publically by the mining companies. They also include potential projects which have been reported, even if the companies have not yet defined the starting date. This method is justified because mining companies usually overestimate throughput rates and are optimistic about commissioning dates. During the last decade, there was a systematic bias towards over-predicting global mining production (UBS Global Research 2017; Wood Mackenzie 2017c). A third method consists in predicting the date of commissioning and the throughput using the price incentive method (Wood Mackenzie 2017a), which forces the more competitive projects to be commissioned first. It implies that demand and secondary supply are known previously and requires detailed cost data of the greenfield projects. The method, nevertheless, does not consider the time required for commissioning and only considers a modest part of the available brownfield projects.
The motivation of this article was to explore the potential production of the Chilean copper mining industry through 2035, considering that the country is the world’s largest producer and holds the biggest ore reserves and resources globally. It is of importance for the copper industry to understand such potential and also find its limitations. Therefore, the aim of this article is to analyze the production potential and some of the main challenges of Chilean copper mining through 2035, assuming that metal price, the regulatory environment, and other competitive aspects of the country should not limit project development and production growth. Therefore, the article provides an unobstructed view on what is technically possible, but does not provide all the real challenges that the industry will face in the future, since it ignores three main challenges in the future which would be economic, regulatory, and environmental.
This scenario is referred to as the “Full Scenario.” As a result, this paper estimates the maximum total copper production of Chile that could be achieved from 2019 to 2035, given the assumptions indicated.
The article addresses the production of copper in concentrates and cathodes. The earlier is employed for processing mainly primary sulfides ores and includes a concentration process based on froth flotation, which must be followed by smelting and electro refining in order to obtain refined metal. The latter starts from oxide ores or even secondary sulfides, resulting in copper cathodes via leaching, solvent extraction, and electrowinning processes (Leach/SX/EW). In 2018, Chile produced 5.8 million tons of contained copper, of which 47.8% were exported as concentrates, 25.2% were smelted in Chile, and 27% were cathodes produced via Leach/SX/EW.
This paper also addresses the availability of ore resources and reserves in the country. In particular, if they will represent a constraint if Chile increases its copper production through 2035 according to the full scenario.
The variables included in this work to evaluate challenges of the industry in this scenario are the following: ore grades, energy and water consumptions, GHG emissions, and generation and disposal of tailings. All these elements have been considered key in studying the copper mining environmental footprint by Lagos et al. (2018), Ali et al. (2017), Aivazidou et al. (2016), European Commission (2016), IISD (2016), Northey et al. (2013, 2016), Schoenberger (2016), Spuerk et al. (2017), Mahdi Badiozamania and Askari-Nasabb (2014), Jeswiet et al. (2015), Nguyen et al. (2014), Harmsen et al. (2013), Mudd et al. (2012), Norgate and Jahanshahi (2007), Norgate and Haque (2010), Norgate and Jahanshahi (2011), Matthews et al. (2008), Kuckshinrichs et al. (2007), and Hondo (2005).
“Methods” of this paper discusses the framework used to estimate mining production and other variables. “Results” presents the results obtained. “Discussion” contains a discussion and “Conclusions” closes the article with some conclusions.
This section is divided in two parts: the first one addresses the framework for projecting production and the second presents the methods to estimate the remaining reserves, energy and water consumption, as well as tailing generation and GHG emissions.
Framework for a mining production projection
The construction of a mining project should begin once the basic engineering is concluded, environmental permits exist, and no law suits are presented against it in the justice system. Table S.1 (in Electronic Supplementary Material) contains an estimation of the minimum time required from 2019 onwards to commission the 15 greenfield and 27 brownfield projects considered in this work. These projects include extensions of the life of the mines, expansions of capacity, and new projects.
According to the information available, many of the secondary oxide deposits processed via leaching, solvent extraction, and electrowinning (Leach/SX/EW) will come to an end prior to 2030 (Table S.1). This means that there will be an economic incentive to develop the copper hypogene ore bodies that underlie the currently exploited oxide deposits, making it possible to avoid high closure costs and take advantage of existing installations. Hypogene deposits contain primary sulfide copper minerals, which at present must be processed via a concentrator plant.
A feature of almost all the Chilean sulfide deposits is that they have a greater amount of resources and reserves than the oxide deposits above them, so their useful life should extend beyond 2035.Footnote 1 A second characteristic of hypogene deposits is that the metal ore grade would begin to diminish as of the time of commissioning, because typically the higher copper grades are nearer the surface in the enrichment zone (Lagos et al. 2018).
The calculation of the copper production in concentrates was made considering the capacity of concentrator plants (Cc,j) in thousand tons of ore throughput per day (ktpd), the copper recovery at those plants (R), and copper ore grade fed to them (λj), for the year j.
Values for concentrator capacities and ore grades were adopted from the literature and from Wood Mackenzie (2017b), for each operation/project. While the plant capacity remains constant in most cases (unless there is an expansion), ore grades change every year for each mine. Recovery values were ascribed for each plant according to literature data for each project and from Wood Mackenzie. The minimum value of R assigned was 70% while the average and maximum values were 86% and 94%, respectively.
Data used for plant capacity, ore grades, and recoveries were adopted from Wood Mackenzie (2017b), from technical literature and from annual reports of companies.
The remaining reserves of copper ore in Chile were reported by the Central Bank (2001) for the period 1985–1997 and by the United States Geological Survey (USGS) from 1998 onwards (USGS 2017). Remaining reserves are those available after discounting yearly refined production. Three scenarios were considered for future copper reserves in Chile. A first scenario whereby there are no new reserves from 2019 onward, a second scenario where the average growth of reserves per year was equal to 3.4% (the same rate occurred between 1985 and 2015), and a third scenario where the reserves’ average growth per year was 5.97% (average growth rate between 2000 and 2015). Higher reserve growth during the latter period was due to great pressure for the primary refined supply to catch up with demand during the commodity boom (2003–2011), which translated into higher exploration expenditures during those years (S&P 2018).
Electric energy use to 2035 was estimated separately for open pits, underground mines, concentrator plants, leaching-SX-EW plants, smelters, electrorefining, and services. The methodology employed to estimate the energy was similar to that used by Cochilco (2017b):
where Et,j is the total electric energy used in Chilean copper mining for the year j and the subscript i is used to denote copper processes; it takes the values O, U, C, S, R, H, Ser, Des, and El, corresponding to open pit mine, underground mine, concentrator, smelter, electrorefining, hydrometallurgy (leaching-solvent extraction-electrowinning), services, as well as water desalination transport and elevation to the mine sites, respectively.
Equation (2) is also expressed in the following form:
where Ωi,j is the unit coefficient by process for each year and its units are in MJ/t of refined copper (copper contained in final products like concentrates, electrowon cathodes, or electrorefined cathodes) for all processes except for the concentrator (MJ/t processed mineral) and the smelter (MJ/t of processed concentrate). The variable Q in the equation is tons of refined copper per year for all processes except the concentrator (tons of mineral treated) and the smelter (tons of concentrate treated).
The average unit coefficients for each of these processes (Ωi,j) were estimated by Cochilco (2015, 2017a) for the period 2001–2016; then, a logarithmic linear regression was employed to project those coefficients until 2035. This method was used by Cochilco (2017b) for its own forecasts. The effects of newer technologies, reducing ore grades, changes in rock hardness, and increasing haulage distances are included in the estimation of future energy unit coefficients.
The consumption of electric energy for water desalination (EDes,j), transport, and elevation (EEl,j) to the mine sites for the year j was estimated in two steps (Untec 2013; Cochilco 2017b). First, the power to desalinize is given by the following equation:
where χ is the standard unit coefficient for the desalination of water and VD,j is the desalinized water volume in the year j. The second step involves estimating the energy required to transport and elevate the water (desalinized or not desalinized seawater):
where g is the gravitational acceleration constant, VEl,j is the water volume for the year j, h is the height (the average of all operations), ηb is the efficiency of pumps, and ηm is the efficiency of the motors. The average altitude above sea level of all projects considered was estimated to be 2750 m.
The total electric energy needed for using desalinized seawater is equal to the sum of both components.
In the case of the traditional process via concentration, the following equation was used to estimate the electric energy consumed by mines, mill plants, and services in the production of copper concentrates, where QCon,j represents the production of copper contained in concentrates and QT,j is the Chile’s total copper contained production:
For the estimation of mine and Leach/SX/EW energy consumption, the following equation was used:
where QH,j is the electrowon cathode production.
The methodology used to estimate the consumption of fuel was the same used for electric energy, and hence was estimated separately for open pits, underground mines, concentrator plants, leaching-SX-EW plants, smelters, electrorefining, and services. The corresponding unit coefficient by process for each year was projected until 2035 using a logarithmic linear regression of the unit coefficients for the 2001–2016 period (Cochilco 2015, 2017a), except in the case of open pit mines where a linear regression was used.
New water usage estimations were made considering average data reported by Cochilco for 2015 (Cochilco 2016a). Unit consumption coefficients for 2015 were used for all years up to 2035, assuming that there would be no recirculation or efficiency improvements in the future. These calculations were compared to the estimates made by US Geological Survey (Bleiwas 2012). Then, new water consumed was calculated considering the methodology used by Cochilco (2017c) using the following expression:
where Wt,j refers to total new water for the year j. The subscript i takes the values C, H, SR, and Ot for concentration, hydrometallurgical process (Leach/SX/EW), smelting and refining, and other processes, respectively. Smelters and refineries are considered only for the current production since no expansions or closures are expected during the study period. The term Ψ refers to the new water unit coefficient by process for each year j expressed in m3/t of refined copper but for the mill plants (m3/t processed mineral); and Q is tons of refined copper produced per year except for the concentrators (tons of mineral processed).
It was assumed that Vizcachitas, Andina expansion, El Teniente expansion, and a fraction of the Cerro Casale project would use new continental water. It also assumes that all new seawater requirements would be desalinized unless particular mines currently using direct seawater. Consumption for processed material at the mill remained constant at 0.63 m3/t of mineral in concentrators. Specific unit coefficients for Leach/SX/EW processes, for smelters, and for other uses, including mines, services, and human consumption, were considered constant in terms of m3/t of copper contained. It also assumes that permits for the 2 cubic meters per second that would cease to be used in hydrometallurgy by 2035 would not be rescinded and therefore companies that exploit hypogene deposits underneath the oxide deposits would use these rights.
Estimation of new water consumed in the traditional process via concentration by mines, mill plants, and services used the same partitioning method as that expressed in equation 6, whereas new water consumed in the mine for Leach/SX/EW processes used the same method expressed in equation 7.
The mass of tailings disposed per year was estimated with a mass balance considering an average concentrate grade of 26.6% of copper content (equation 9). This value corresponds to the global average grade of copper concentrates from 2013 to 2015 according to Wood Mackenzie (2015). Chile’s average is similar to this value.
where QTail,j is the tailing mass disposed on year j, QC,j is the mineral processed in the concentrator, and QCp,j is the concentrate produced on the same year, all expressed in tons.
Greenhouse gas emissions
The greenhouse gas emissions (GHG) were estimated for scopes 1 (direct emissions) and 2 (indirect emissions). However, Matthews et al. (2008) argue that scopes 1 and 2 emissions of an average industry are only 14% and 12% of the emissions of the total supply chain up to the production gate, respectively; and Downie and Stubbs (2013) affirm that scope 3 emissions often may constitute up to 75% of the overall GHG footprint in many industrial firms. In this work, the direct emissions were calculated from the combustion of fossil fuels in all the processes, considering the emission of gases relevant to this industry: CO2, CH4, and N2O. The method for scope 1 was adopted from the Tier 1 approach from the Intergovernmental Panel on Climate Change (IPCC 2006):
where GHG includes CO2, CH4, and N2O. The subscript i takes the values of the most relevant fuels in the industry, in this case diesel oil, fuel oil, and natural gas, whose relative shares were obtained from Cochilco (2016b). The emissions of a given GHG are expressed in kg of CO2 equivalent, the fuel consumption is expressed in (TJ), the emission factors in kg GHG/TJ (IPCC 2006), and the Global Warming Potential index takes the value of 1 for CO2, 25 for CH4, and 298 for N2O.
The GHG scope 2 emissions were derived from purchased electric energy consumption with the location-based method, using grid average emissions factor data (WRI, WBCSD 2015). Until 2017, the copper mining industry in Chile consumed electric energy from two independent grids, the SING (Sistema Interconectado del Norte Grande) and SIC (Sistema Interconectado Central), which serve the north and central regions of the country, respectively. The SING grid has a predominant share of fossil fuel-based generation and SIC a predominant hydroelectric-based technologies. From 2018 onwards, these grids were merged into the National Electric Grid System (SEN). The average emission factor for these grids, for each year j, was calculated with the following equation:
EFg,j: grid average emission factor (kg GHG CO2eq/TJ), for grid g and year j.
i: electric energy generation technology.
Efi: emission factor of electric generation technology i (kg GHG CO2eq/TJ).
Eg,i,j: sold energy by the grid g from electric generation technology i (TJ).
The emission factors for all electric generation technologies were obtained from Schlömer et al. (2014) and BERR (2008). The historic energy sold by both grids and by different electric generation technologies was obtained from the Comision Nacional de Energia (2017), and the projected data to 2035 was estimated considering that all the additional electric energy required by mining would originate from solar plants (CDEC-SIC 2016). Finally, the GHG scope 2 emissions for every year j were obtained from Eq. (12):
Production projections for Chile’s four mining regions are presented first, followed by concentrate production, ore grades, remaining reserves, and yearly production. Energy and water consumption, tailing generation, and GHG emissions associated to those productions are then presented.
Figures 1, 2, 3, and 4 show the production of contained copper in Chile and in the copper-producing regions of the country in a full scenario until 2035. These figures show peaks in production between 2027 and 2030, depending on the region analyzed. As expected, the production estimated for Chile is much higher than those reported by Cochilco (2019a) and Wood Mackenzie (2017c). These numbers show that Tarapaca and Antofagasta will continue to lead national production, and the central macro zone, which includes Coquimbo, Valparaiso, Santiago, and O’Higgins regions, would more than double its present output.
Figure 5 shows that copper produced via Leach/SX/EW will substantially decline after 2025, due to the exhaustion of oxide reserves in most mines.
Ore grades decline
The cause for the severe decline of ore grades to be fed to concentrators between 2017 and 2025 is the commissioning of hypogene deposits with initial low ore grades (between 0.5 and 0.7% of copper contained), whereas the decline of ore grades in the very large sulfide ore deposits already being exploited is moderate, as observed in Fig. 6. This behavior can be expected to continue beyond 2035. Figure 6 also indicates that ore grades fed to Chilean mills until 2025 would decline at a rate of 0.58% per year. The decrease from these levels to ore grades below 0.5% should be very slow. These results agree with the conclusions of Northey et al. (2014) who found that ore grade decline may abate in the future because mined ore are approaching average ore grades in reserves. A complementary view is provided by West (2011) who contends that improved extractive technologies to exploit very low grade deposits drove the decline in ore grades in the last two decades.
Figure 7 shows future (2019–2035) production and remaining reserves for Chile’s full scenario. It is observed that the decrease in production is not due to reserve scarcity, even in the most conservative scenario. This is in agreement with the findings in Mudd and Jowitt (2018) who showed strong evidence of growth in known mineral resources rather than evidence of resource depletion. The fixed base scenario considers that none of the existing resources will become reserves after 2015. The highest reserve growth rate of the 2000–2015 period illustrates that a demand/price boom, as the one that occurred between 2003 and 2012, not only fosters exploration but also transforms mineral resources into reserves that would not be economically extractable at lower prices (Tilton 2003; Tilton et al. 2018).
Figure 7 illustrates that even in the “Full scenario”, existing reserves cannot be extracted faster in the period studied with the current knowledge and technology. It also shows that the peaks observed in production (Figs. 1, 2, 3, and 7) are not due to an exhaustion of reserves but to other constraints.
Mining environmental footprint: energy, water, greenhouse gas emissions, and tailing generation
Figure 8 presents indices for copper production, use of energy (electricity and fuels) and water, the generation of tailings, and the emission of greenhouse gases per year until 2035, considering that the index for 2015 is one. The data used to construct these figures also can be found in Table S.2 (in Electronic Supplementary Material). As previously stated, the electric energy estimation for the full scenario considers that all the additional electric energy required by the Chilean mining would originate from solar energy plants (CDEC-SIC 2016). This assumption is justified considering the evolution of electric energy costs and the excellent conditions of northern Chile to produce solar power. An additional reason for replacing coal and natural gas by solar energy is that the time required for obtaining environmental permits, and the potential challenges from the community to thermal power, would be reduced on solar-based projects.
Figures 9a and b show the allocation of electric consumption in 2015 and 2035. The main electric energy consumption in 2035 would be in concentrators, followed by desalinization plus water transport to the mines. Production in Leach/SX/EW operations decreases from 24.5% in 2015 to 1.7% in 2035. The electric consumption participation of underground and open pit mines decreases moderately from 7.4% in 2015 to 6% in 2035. While growth of electric energy occurs fundamentally in concentrators due to increased throughput and rock hardness, reaching 69.7% of the total electric energy (Fig. 9b), growth of fuel consumption occurs mainly in open pit due to increased material extraction and haulage distances, reaching 81.6% of total fuel energy in 2035 compared to 77% in 2015. Table 1 shows that electric energy consumption per ton of copper of mine to concentrator in 2015 and in 2035 is within range of the values reported by Northey et al. (2013).
More seawater used in mining implies higher electric energy consumption; thus, synergies for minimizing impacts of both variables should be identified (Nguyen et al. 2014). This is particularly important for Chile, considering that extraction of seawater and desalination does not have local standards.
Electric energy consumption due to desalination and water pumping was added to these estimations. While in 2015, 3.5% of electric energy was allocated to these activities; in 2035, this value would be 16% of total demand. Nevertheless, due to deepening of open pit and ore grades decline, the electric energy usage would double in this period without considering seawater extraction, desalinization, and transport.
Seawater began to be used at a massive scale in recent years, increasing from 2.5% in 2009 to 14.8% in 2015 (Cochilco 2017a) and would be 60.5% in 2035 in the full scenario. Such change was motivated by the severe continental water scarcity in most producing regions in the country, generating uncertainty in the supply for mining activities. This fact was indicated by Northey et al. (2017) for copper resources globally.
Hydrometallurgy used to consume 2.4 cubic meters per second of water in 2015, representing 15.7% of the total water required by copper mining operations. Almost all this amount came from the extraction of fresh water. In 2035, hydrometallurgy would only be using 0.38 cubic meters per second in this full scenario, i.e., 1% of the total water used in copper mining.
Figure 10 shows that consumption of continental water should decrease from 13.1 m3/s in 2015 to 10.8 m3/s in 2021 because of the projected construction of desalination plants and pumping systems of seawater announced until 2017. Growth of continental water consumption after 2021 would occur only in the central region of Chile. Values shown in Table 1 for concentrate production are within the values reported by Northey et al. (2013) of 33.8 to 350 m3/t of copper contained, with an average of 70.4 m3/t. Northey et al. (2013) also indicate that water consumption for processes including mine and Leach/SX/EW varies between 22 and 47 m3/t of copper contained, which is similar to the value cited in Table 1.
Direct GHG emissions in 2035 increase 55% more than copper production, while indirect GHG emissions increase 18.3% less than copper contained production up to 2035. The latter is due to the interconnection of the two electric grids of the country and to the growth of non-conventional renewable energies (CDEC-SIC 2016). The direct GHG emissions per ton of copper will change from 0.98 t CO2 eq/t of copper in 2015 to a maximum of 1.53 t CO2 eq/t of copper in 2035, if the continuation of use of diesel trucks and other vehicles occurs, whereas indirect GHG emissions per ton of copper contained has a maximum coefficient of 2.68 t CO2 eq/t of copper reached in 2016, decreasing to a minimum of 1.62 t CO2 eq/t of copper in 2019, to increase again afterwards because the composition of the grid will incorporate liquified natural gas (LNG) and small sources of diesel and fuel oil. These values are within GHG emission ranges of scopes 1 to 3, as reported by Northey et al. (2013), which contain high variability from mine to mine due to processing configurations, ore mineralogy, sources of energy, hardness of the rock, and transport distances.
The tailing mass produced per year by 2035 would be 3.25 times the 2015 value. Replacing the grinding/flotation process by a technology that generates a more favorable waste to ore ratio remains as one of the greatest technological challenges for the mining industry (Gutberlet 2015).
The full scenario predicts that from 2027 to 2030, Chile would produce over 10 million tons of copper per year, decreasing afterwards to reach 8.6 million in 2035 due to the closure of oxide mines and a reduction in the ore grades of sulfide operations. It is estimated that copper exports in concentrates would reach 8.1 million tons in 2029, compared with 2.5 million in 2015. This would accentuate the vulnerability of Chile with respect to treatment and refining charges.
Three technological issues were identified as barriers to swift production expansion rates. The first barrier stems from a vertical morphology of several large deposits, including Escondida, Andina, and others. This may preclude very large expansions such as the one designed for the Andina mine a few years ago, with a 350 ktpd capacity of its concentrator. Whatever the method chosen by Andina to exploit its deposit, the full extent of reserves may not be recovered due to limitations imposed by nearby glaciers and the design rules elaborated by Codelco to guarantee that glaciers would not be affected by copper extraction. Similar issues would be possibly faced by Los Bronces and Pelambres minesites.
The second technological barrier is the complexity of expanding the throughput capacity of very large underground mines, such as Chuquicamata and El Teniente, which are the largest in the world for these types of operations.
The third technological barrier arises in Escondida where material moved reached close to 1.5 million tons per day in 2017 (Wood Mackenzie 2017b). Adding the OGP2 concentrator (Table S.1) would increase this number to approximately 1.7 million tons per day. The need for introduction of new equipment and transport methods to handle this load is a serious matter for the future.
What emerges from the analysis is that mine reserves and resources are not equivalent to production potential but in a prolonged period of time. Therefore, country production potential in the short to mid-term is not the same as the sum of all its mine reserves and resources. While many very large mines in Chile have enough known reserves and resources to produce well beyond 2050 at the rates required by the full scenario, not all of them could increase the rate of extraction beyond the full scenario unless there are breakthroughs in technology.
Chile’s copper production projections up to 2035, shown in Fig. 1, are limited by factors not associated with known reserves, as is illustrated in Fig. 7. In fact, reserves and resources for the mines considered in this work were 610 million tons of copper in 2017 (detailed data is shown in Table S.3, in Electronic Supplementary Material), more than enough to sustain production up to 2035 even in this full scenario. Namely, the identified limitations consist of the knowledge of the projects that could be developed as well as the aforementioned technology limitations. Both of these reasons caused production peaks in Figs. 1, 2, 3, 5, and 7, and in projections elaborated by other authors such as Hernandez (2009) and Wood Mackenzie (2017c).
The summits shown by these production projections, nevertheless, are very different from production peaks, as defined by the peak production theory, which assumes that these maximums are caused by resource exhaustion (Northey et al. 2014; Ali et al. 2017). After peaks occur, primary production should start to diminish, according to convention. The peak production theory was originated for oil production and dates back to the beginning of the XXth century (Radetzki and Warrel 2017). It affirms that oil production will peak when one half of recoverable resources have been exploited. This theory is supported by the Association of the Study of Peak Oil (ASPO) which has been predicting for several decades that peak oil production should occur one or two decades later.
It can be argued, therefore, that the summit production identified in this paper is only an apparent one. When climbers get closer to the summit, a second summit may be in view, an effect that may continue until the ultimate physical peak is reached. A more appropriate denomination for such production maximums, therefore, could be “false summits.”
Three environmental issues are of top priority for the mining industry in Chile in 2020. First, the construction of new tailings deposits or their expansion, second, mining in the vicinity of glaciers, and third the use of continental water.
New and expanded tailing dams would use additional territory, as is evident from the volume growth of tailings estimated in the full scenario, and this should constitute a key obstacle to the production growth of copper mining in highly populated areas and in agricultural regions (Zegarra 2016), both conditions that are present in Coquimbo, Valparaiso, Santiago, and O’Higgins regions (Valor Minero 2017). New tailing deposits could possibly be authorized in this extensive region of the country only for filtered tailings, with a maximum water content of 15%, compared with up to 70% water of the traditional tailings deposit technology. Filtered deposits not only reduce the use of water and land, but also present less risk of catastrophic failure when properly managed (Davies 2011; Klohn 2017). The 15 largest Chilean tailings dams, which serve 93% of copper production in the country, are constructed using the downstream method and coarse particle material for the dam wall. These deposits successfully withstood all large earthquakes in Chile during the last 55 years, including the 8.8 Richter scale earthquake of March 11, 2010, offshore of the Maule Region in the south of the country, and the 8.3 Richter scale earthquake of September 16, 2015 offshore of the Coquimbo Region in the north of the country. The last catastrophic failure of a large tailing deposit in Chile occurred on March 28, 1965 in the El Cobre deposit, and was caused by the earthquake of La Ligua district (Richter scale 7.2), located 130 km north of Santiago. It killed an estimated 200 people. This deposit had been constructed with the upstream method, which was prohibited by regulation ever since.
The two large catastrophic failures of tailings deposits that occurred since 2015 in the region of Minas Gerais, Brazil, were constructed with the upstream method and produced worldwide alarm due to their consequences. First, the Samarco tailing dam collapsed on November 5, 2015 and afterwards the Brumadinho tailings dam collapsed on January 25, 2019, generating large loss of life and also significant destruction of the environment.
The events described in Brazil elevated the social and regulatory resistance to the construction of tailing dams in Chile, in spite of the fact that no new regulations were issued. The construction of new tailing dams and the expansion of existing deposits is possibly the greatest environmental challenge that the copper mining industry faces for its expansion and even for its continuation in a large area of Chile that does not include the northern regions, largely desertic, of Antofagasta, Tarapaca, and parts of Atacama.
Another environmental obstacle faced by the copper mining industry in Chile are the potential effects of mining operations close to existing glaciers in the Andes Mountains. A law project was created in the Senate on July 4th, 2018 (Chilean Senate 2018) which aimed to restrict new mining developments close to existing glaciers. This law was under intense discussion in the country since 2018 and its approval would possibly restrict the expansion of several of the very large copper and gold tailings deposits in Chile, including El Teniente, Andina, Los Bronces, Los Pelambres, and Pascua Lama, among others. One alternative is to require case-by-case evaluation and eventual acceptance of mining greenfield and brownfield projects under the Environmental Evaluation System that operates in the country.
The discussion about glaciers intensified in 2019 and 2020 due to the prolonged drought in large regions of Chile, causing a heated debate in the communication media, accusing the mining industry’s use of continental water rights which were essential for human consumption and for agriculture, especially in the regions south of Atacama. The solution proposed by some environmental NGOs, would be that mining should yield these rights in benefit of the population and of the country.
This debate lead the mining companies located south of this region to plan for the use of seawater, either raw or desalinized, in order to meet operational mining extraction and processing demand in the future. The replacement of continental water by seawater was not considered for this part of the country in the full scenario.
It is assumed that all new electric energy demand required by the full scenario would be met by renewable energies, especially, solar energy.
It was estimated that 14.6 TWh will be required for new copper mining projects and expansions by 2035, including water desalination and pumping, in the full scenario. This could be achieved with renewable energy, especially solar power. It is unlikely that it will be based on hydropower because most mining in Chile is located in desert regions, and there are no new plans to construct important hydroelectric power dams in central Chile. The land used by solar power installations that could deliver the new energy required by the full scenario, was conservatively estimated to be 2% of the surface of the Antofagasta region, whose population density is 4.6 inhabitants per square kilometer. The investment to do so would be competitive with the investment required for installing gas powered stations.
The country would use 144 TWh in 2035, of which mining will use 53.2 TWh in the full scenario. This total corresponds to the non conventional renewable energy scenarioFootnote 2 of the CDEC SIC 2016 study, plus the requirements of the full mining scenario. The total renewable energy of the country grid would be 61.7% in 2035. This paper assumed that the composition of the mining electric grid will be the same as that of the country’s grid, in spite of the fact that some mining companies have already subscribed contracts to fund total solar power for their operations.
Northey et al. (2014) assert that the increase of energy and water usage, as well as GHG emissions resulting from increasing production and declining ore grades, will present barriers to the continuing expansion of the global mining industry this century. The scenario developed in this paper challenges this view because all the new electric energy required for copper mining would be based on solar power, which is very abundant in the country (especially in the mining regions of the north). Regarding the environmental footprint of seawater extraction, desalination, and transportation, the use of solar energy would not imply a significant increase in GHG emissions. The extraction of seawater and the return of salt brines to the ocean may imply, nevertheless, important environmental impacts if a proper facility design based on comprehensive environmental information is not carried out (Roberts et al. 2010; Missimer and Maliva 2018).
This article provides an unobstructed view on what is possible, from a technical and resource perspective, for the Chilean copper mining industry through 2035, but by design, it does not provide all the real challenges that mining will face, since it ignores three main challenges in the future, which would be economic, regulatory, and environmental.
The accelerated mining extraction of Chilean copper reserves and parts of its resources were studied in the upcoming 15-year period in a “Full Scenario,” identifying and quantifying productive and resource impacts and challenges.
In this scenario, Chile would produce 143.7 million tons of copper from 2019 to 2035, short of the 210 million tons of remaining reserves estimated by the USGS in 2017 (USGS 2018). Reserves and resources for the mines considered in this work were 610 million tons of copper in 2017.
The maximum production identified in this work for 2027 to 2030 and its subsequent decrease is associated with a lack of present knowledge about the projects that could be developed, and with the technologies to economically increase the rate of extraction, rather than to the lack of ore reserves and resources. Therefore, the maximum production estimated is associated with a false summit rather than with peak production. Once a false summit is reached, the real summit or another false summit appears in view, and climbing can continue. On the contrary, after reaching the peak, the only alternative is to go down.
Exploitation of the highest-grade reserves first cannot be achieved optimally because these are mainly present in the very large deposits where this work identified technological barriers to increase the rate of extraction. Therefore, low grade deposits would start to be exploited simultaneously with the expansion of high-grade existing mines.
The construction of new tailings dams and the expansion of existing deposits is possibly the greatest environmental challenge that the copper mining industry faces for its expansion and even for its continuation in a large area of Chile located from the Atacama region towards the south of the country. The existing tailing deposits in this part of the country have the capacity to accommodate tailings estimated in the “full scenario” up to 2035, and possibly beyond, without resourcing to the construction of new deposits. But the exploitation of the very large copper deposits could continue for many more decades, and new tailing deposits will be required. It is likely, that environmental permits to construct such new tailings deposits in this part of Chile, would require the most advanced available technologies. In spite of the fact that existing large tailings deposits in Chile have successfully withstood all earthquakes occurred during the last 55 years, new tailing dams using the most advanced technologies should reduce even more, the risk of catastrophic failure.
New water required for the expansion of copper mining does not represent a resource obstacle in the country, because all of it would be extracted from the ocean, for 38, out of the 42 projects considered in this work. The remaining mining projects could, if required, bring seawater for extraction and processing of the ores.
A restrictive regulation prohibiting to operate in the vicinity of glaciers could hinder the expansion of some of the largest copper and gold deposits located from the Atacama region towards the south of the country.
The new electrical energy required for the expansion of copper mining would not represent a resource obstacle anymore because it would be based on solar power or other renewable resources, which are abundant and cheap in the country, especially in its mining regions. This, added to the merge of the two electric grids in Chile during 2018, is estimated to cause a modest increase in the indirect GHG emissions of copper mining in the country, with a significant decrease of the unit coefficient per ton of copper produced.
Only a couple of oxide operations in Chile are based on exotic copper deposits that do not have a sulfide orebody below them: Mina Sur in Chuquicamata district and El Tesoro in Centinela district.
This scenario includes conventional renewable energies.
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We thank the many people in industry and academia that commented on the potential mining projects that could be constructed in Chile in the period through 2035. We specially thank comments by Diego Hernandez of the National Society for Mining (Sonami), Nelson Pizarro of Codelco (former CEO), Gerhard von Borries of Codelco, Ricardo Alvarez of Mitsui, Juan Carlos Román of Anglo American, Rodrigo Moya of Antofagasta Minerals (AMSA) and Robert Mayne Nichols of Empresa Nacional de Minería (Enami), and Professors Julio Beniscelli, Juan Carlos Salas and Patricio Lillo of the Department of Mining Engineering at the Pontificia Universidad Católica de Chile.
This research was funded by the Mineral Economics Program of the Pontificia Universidad Católica de Chile.
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Lagos, G., Peters, D., Lima, M. et al. Potential copper production through 2035 in Chile. Miner Econ 33, 43–56 (2020). https://doi.org/10.1007/s13563-020-00227-2
- Copper production
- Scenario 2035