European Geologist Journal 45
Mining non-renewable mineral resources in a sustainable way
by Tommi Kauppila1
1 Geological Survey of Finland
The concept of environmental sustainability is crucial for the mineral sector, which utilises non-renewable natural resources. This paper introduces concepts that allow sustainable mining. The natural capital lost during mining can be substituted with other forms of capital, and revenues from mining are invested in reproducible capital or renewables-based substituting materials. Furthermore, a deposit-based sustainability model is described in which the ability of future generations to utilise mineral deposits rather than minerals themselves is intentionally maintained through investments in exploration, data collection, research, and development of improved technologies. At the same time, any losses of natural capital during mining are minimised and attempts are made to maximise the local social and economic benefits in a sustainable way.
Sustainability, environmental sustainability, and sustainable development
Sustainability is one of the most commonly used buzzwords of our modern, environmentally conscious society. As a concept, sustainability is the ability of systems and processes to remain functional and continue their intended behaviour, basically indefinitely. From a human point of view, sustainability refers to our ability to manage environmental, economic, and social issues and to maintain these ‘pillars of sustainability’ in the long term.
For a long time, sustainability was considered to be more or less synonymous with sustainable development, the most popular definition of which appears in the Brundtland Commission’s final report in 1987 as development that meets the needs of the present without compromising the ability of future generations to meet their own needs. The report emphasises that a new era of economic growth is required to meet even the essential needs of people in a world where poverty is widespread. The Brundtland report also points out that environment and development are inseparable, because the environment is where we all live and it does not exist as a sphere separate from human actions and needs.
To solve the sustainability problem of the human economy, the environmental sustainability part of the equation also must be balanced. Since the seminal paper of Daly (1990), environmental sustainability has commonly been divided into three conditions that need to be satisfied: the harvest rates for renewable resources should not exceed their regeneration rates; the rates of waste emissions should not exceed the natural assimilative capacities of the ecosystems into which the wastes are emitted; and the depletion of non-renewable (exhaustible) resources should be matched by the rate of creation of renewable substitutes for these resources.
Non-renewable resources and sustainable development
Non-renewable resources, such as those obtained from mining, are particularly problematic in the sustainability context due to their inherently finite quantity. Fortunately, many non-renewable materials, especially metals, can be reused and recycled many times over without losing their intrinsic properties. Many products that are made of metals also stay in use for long periods of time. However, sustainability is a critical issue for the primary mineral sector, which is mining deposits that future generations could also utilise to meet their material needs.
For utilisation of non-renewable resources to be sustainable, the concept of weak sustainability needs to be invoked. It allows the use of natural capital (e.g., mineral deposits) as long as the capital lost is substituted with an equal amount of other types of capital such as manufactured, human or social capital. This is taken into account when investing the revenue generated by resource utilisation in reproducible capital such as machines (Solow, 1973; Hartwick, 1977). Weak sustainability is in agreement with the human-centric, Brundtland type of sustainable development which emphasises the alleviation of poverty and both global and intergenerational equity. In addition, many new environmental and energy technologies are based on the use of technology metals and other mineral-based materials, enhancing the environmental pillar of sustainability.
The Daly type of substitution is more restrictive than the interchangeability of different forms of capital in the concept of weak sustainability. Daly emphasises efforts to directly substitute non-renewable materials with other, renewables-based materials (or energy) as the main form of substitution to achieve ‘quasi-sustainable’ development. This is a more technically oriented approach and, if successful, is especially beneficial for the environmental sustainability pillar.
Minerals are mined from deposits
Besides substitution between different types of capital or between types of materials, a third type of substitution can be envisaged for the mineral sector. A unique feature of the mining industry is the concept of commercially valuable (ore) deposits in which minerals and elements are found in concentrations, volumes, and forms that provide for technically feasible and economically viable mining. It is these deposits that future generations also could benefit from, but individual deposits and their geodiversity are eventually depleted if we mine them now.
While it may be theoretically possible for humankind to mine out the whole crust of the earth, this is exceedingly difficult in practice. At least the topmost two kilometres of the 30-50 km thick, 150 × 106 km2 continental crust are within reach for humans, even with current mining technologies. For the foreseeable future, therefore, we can make an assumption that, assuming high levels of recycling, the earth’s crust as a whole contains enough useful minerals and elements to satisfy the needs of a human population of a size that the renewable resources on Earth can sustain. However, mineral deposits that readily lend themselves for economically and technically feasible mining are in much shorter supply. The deposit-based sustainability approach thus presents us with a third mode of substitution unique to the mining industry – the possibility to identify new mineral deposits and develop methods to utilise them for future generations. In the following sections, individual approaches to make mining of non-renewable materials more sustainable are discussed in more detail.
Maintaining our stock of identified mineral resources through public and private research
To replace the deposits that we exhaust by mining, we must identify and study new deposits, also considering future generations and the very long lead times from prospecting to mining. A major part of this work must rely on commercial exploration activities. However, exploration is a high risk economic undertaking with low and declining success rates (see e.g. Grennan & Clifford, 2017). The attractiveness of a region for exploration and mining investment depends on several factors such as the geological potential, security of tenure, effectiveness and predictability of the administrative process, manageable taxation and trade regime, and adequate infrastructure.
The geological potential of a region may seem like a fixed endowment, but even this feature can be improved, or at least boosted. This is done by investing in high quality geological research and education, and in collection, management, and delivery of geological, geophysical, and geochemical data. Modern methods for digital geodata management, analysis, presentation, and delivery provide unprecedented possibilities for disseminating geological databases to promote exploration. In addition, a great deal of progress has been made in the field of standardisation of spatial data specifications and interoperability of spatial data sets and services in Europe. It makes a lot of sense to invest in national level data management, attempting to collect all relevant data from all sources and manage them in a coherent way.
Besides the geological potential and geological databases, exploration and mining companies look at what is commonly called the policy potential of the jurisdiction. It consists of factors such as the administrative processes regarding exploration and mining projects, security of mineral tenure, public acceptance of mining, the taxation regime, human and physical infrastructure, and trade and labour conditions. A clearly stated and widely accepted mineral policy is essential in informing investors about the intentions and priorities of the jurisdiction regarding the mineral sector. The policy should be implemented efficiently through consistent regulations and ensure conditions that are scientifically valid and protective of the environment, combined with the ability of the authorities to plausibly enforce them. This is the easiest way for a company to show stakeholders and its shareholders that it is operating responsibly.
In many cases commercial exploration activity is not enough to increase the stock of identified mineral occurrences for deposit sustainability. Commodities and deposits that cannot yet be utilised commercially should still be studied for future needs, and the role of public actors such as geological surveys and research institutes is essential here. Public institutions can look for emerging minerals and elements, for instance those with potential to substitute current commodities or elements that can be used in cleantech applications. In addition, more attention can be paid to such minerals in current exploration projects, even if the primary target minerals are conventional ones. A special case here is scanning deposits for minerals that could be used at the mine site itself, typically for environmental applications such as water treatment or waste storage facilities.
Responsible mining is based on viable mines
Environmentally responsible mining is only possible with healthy projects. Not only is it necessary to include all foreseeable environmental expenditures in the feasibility studies, including costs of mine closure and post closure activities, but also to do this with a large enough margin of safety against market fluctuations. This is important especially because poorly planned and premature mine closures can be detrimental from an environmental point of view. In addition, only economically sound mining projects are capable of minimising any mining-related losses of economic, social, and natural capital to make mining more sustainable. They are also in best position to sustain local benefits from mining, both during the life of the mine and after mine closure.
Sustainable mining of individual deposits
Besides maintaining the inventory of identified deposits, individual deposits need to be utilised prudently to minimise any unnecessary losses of natural capital and to maximise the benefits from the project. To this aim, the treated ores must be utilised to the fullest and deposits mined wisely, the lives of mines and their infrastructures must be extended, and waste rocks taken for beneficial uses.
Mining, crushing, and grinding consume a lot of energy and processing typically requires considerable amounts of water. Therefore, it makes sense to utilise the crushed and ground ore as fully as possible. This means recovering as many commodities from the ore as possible and looking for possibilities to use the rest of the material, e.g. for cemented paste backfilling. Fractions that have potential to be valuable at a later stage can be separated and stored for future markets, especially if their removal results in cost savings in waste management.
In addition to utilising the comminuted ore to the fullest, care must be taken not to waste any of the ore in the mining phase or sterilize the rest of the deposit by making its future utilization difficult. Geometallurgical approaches have become a common practice in the industry and this holistic view of the deposit and its processing contributes a great deal to making mining more sustainable. All this needs to be based on adequate drilling of the deposit and skilful modelling of the results to determine optimal cutoffs and processing pathways for the ore.
Environmental sustainability can in many cases also be boosted by seeking to extend the lives of existing operations by brownfield and deep ore exploration. Instead of opening several mines with their own processing plants and waste facilities, well managed single sites could be a more environmentally benign option. Utilisation of existing and shared infrastructure makes sense if deposits are available within reasonable transport distances.
Minimising local impacts and maximising long-term benefits
In addition to utilising the deposit wisely, all other losses of natural capital should be minimised to make mining as sustainable as possible. The highest level of environmental performance is called for here and industry-specific research and development is required to tackle the unique issues in mining that affect environmental management.
Mining operations typically rely on economies of scale to control their operating costs. Processing large quantities of ore requires considerable amounts of water that need to be managed. While other water intensive industries can seek for locations near large water bodies, the location of a mine is fixed at the deposit. After processing, most of the treated ore becomes waste, the amount of which can be considerable. Furthermore, some types of mining waste are reactive and may produce acid, metal-laden drainage for long periods of time if not properly managed. The long timescales involved and the fact that mines have an inherently limited lifetime require that special attention be paid to mine closure and the post-closure period.
Despite these challenges, environmentally responsible mining is possible if the unique features of the industry are taken into account. Tailored environmental management methods for mining are available and best practice manuals and guidance have been published for various topics such as conducting EIAs for mining projects, waste management, acid drainage management and mine closure. The availability of skilled environmental professionals, consulting companies, authorities, and researchers is critical for a properly managed mining industry. Nevertheless, it is clear that the industry is moving towards low impact, low waste mining in which most processes happen underground and any moving of materials is minimised, contributing to the lowest possible losses of natural capital during mining.
According to the principles of weak sustainability, low impact mining should be complemented with measures to ensure sustainable social and economic benefits locally and regionally. This work starts already in the early EIA phase and with early mine closure planning, where post mining land uses are discussed with the local stakeholders. As a general rule, best outcomes are only possible if all planning is done in close collaboration with the local authorities and other stakeholders. A mining project is a large industrial undertaking that in many cases affects the regional labour markets, economy, and demand for public services and housing. However, all mines eventually close and economic diversification has to be promoted early on to secure long-term benefits from the mining project.
Sustainable mineral policies
Besides helping to attract exploration activity through stability and predictability, mineral policies are also one of the main vehicles to promote the sustainability of the mineral sector as a whole. Governments and public administration can manage and stimulate the mineral industry and sustainability aspects can be included in this work. For successful political decision-making on sustainable mineral industry, data and information on the sector needs to be collected, analysed, and distributed in a suitable format (see e.g. Machacek et al. 2017). Data are needed not only on the primary minerals but also secondary sources, because recycling and anthropogenic deposits are becoming increasingly important for the markets of non-renewable material.
Perhaps the trickiest issue in mineral policies is how to best invest the wealth and revenue generated by mining according to the principles of sustainable development. In addition to generating local sustainable benefits through infrastructure and economic diversification, mining revenues should be invested transparently in generating sustainable industries and productive capacities on the national level for long-term net benefits. In doing so, it makes sense to emphasise activities that contribute to sustainability in their own right, such as cleantech and energy technologies. This is also in line with the approach of Daly (1990), who suggested investing specifically in material substitution to compensate for the loss of natural capital due to mining.
One responsible way to invest the revenues from mining is to promote research and development in low impact exploration, mining, processing, environmental technologies, recycling, and substitution for the benefit future generations. New technologies not only reduce the impacts of mining but also make new deposits accessible and their beneficiation feasible, indirectly increasing the stock of deposits we leave behind for future use (e.g., Langefeld, 2017). We should continue accumulating geoscientific observations, developing geological, deposit, and geoenvironmental models, and investing in tailored environmental technologies for mining. Indeed, the EU and many of its member states have invested in research in the mineral sector and non-renewable raw materials through targeted research funding, greatly advancing sustainability in the raw materials sector.
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Daly, H. 1990. Commentary: Toward some operational principles of sustainable development. Ecological Economics 2: 1-6.
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Hartwick, J.M. 1977. Intergenerational Equity and the Investing of Rents from Exhaustible Resources. The American Economic Review 67: 972-974
Langefeld, O. 2017. Future Mining – Thoughts on Mining Trends. European Geologist 44: 15-18.
Machacek, E., Falck, E.W., Delfini, C., Erdmann, L., Petavratzi, E., van der Voet, E. & Cassard, D. 2017. Clearing the sky from the clouds – The Mineral Intelligence Capacity Analysis (MICA) project. European Geologist 44: 48-53.
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This article has been published in European Geologist Journal 45 – Environmentally sustainable mining in Europe
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