One of the goals of the industry now is to focus on the abundance of opportunities for improvement. What better place to affect visible change, than an industry that has faced significant scrutiny in the past? Mining’s link to primary resources doubles as its function, while other industries have layers of production between their product and primary resources, making the extent of their impact less visible. Mining and other primary industries deliver the energy and raw materials that fuel human activity and economic development.

Mining and sustainability is more than a discussion of what we take out of the ground and how effectively and efficiently the product is put to use involves the socioeconomic impact and the sustainability of the communities we touch. This represents a meaningful opportunity to use engineering talents to minimize the footprint of the mining industry.

The Evolution of Sustainability in Mining
The question of sustainability with respect to mining has its origins not in the environmental field, but in the social and economic impacts the primary extractive industries have had on the communities in which they work. The issues confronting mining are older, well known, and long overlooked by governments, sometimes because of the wealth created or strategic significance of the product derived. More than 500 years ago the Incas mined silver at Potosí to fund the Spanish Armada. Exposure, brutal labor conditions and mercury poisoning contributed to the death of the people who worked in the mines. The mountain continues to yield silver today, and those who work at the mines still live in poverty and have a shortened life expectancy. The historic wealth generated by mining has not eliminated all impacts on the surrounding communities.

Pumped storage facilities help meet energy demands during peak-use hours.

The chief executive officers of some of the world’s largest mining companies formed the Global Mining Initiative (GMI) through the World Business Council for Sustainable Development (WBCSD) in 1999. The GMI commissioned a review of the mining and minerals industry’s transition to sustainable development, which resulted in the Mining, Minerals and Sustainable Development Project (MMSD). The MMSD North America project produced several documents that describe the current situation in the mining industry, assess possible outcomes for the future and develop a framework for evaluating a project’s contribution to sustainable development.

The International Council of Mining and Metals (ICMM) was formed in 2002 to implement the findings of the MMSD project and continues to commission and publish guidelines for business conduct, such as the following principles:
• Implement and maintain ethical business practices and sound systems of corporate governance.
• Integrate sustainable development considerations within the corporate decisionmaking process.
• Seek continual improvement of our health and safety performance.
• Seek continual improvement of our environmental performance.
• Facilitate and encourage the responsible design, use, re-use, recycling and disposal of our products.
• Contribute to the social, economic and institutional development of the communities in which we operate.

As a mine exists only to satisfy a market, does a mining company have a moral obligation to preserve the sustainability of the community it serves? It is not the mine itself that is sustainable, as our activities may by definition be transient. But our impacts are lasting, and it is the sustainability of the local community and environment, and society and the planet, that are the measure of our actions. As good stewards of the world’s resources we should do what we can to encourage the wise use of our products.

Applying Technology to Improve Mine Sustainability
A major challenge for the mining industry is overcoming the sometimes conflicting pressures of the short-term market and long-term sustainability goals. The most effective way to achieve sustainability goals is to provide realistic, long-term solutions that can be reasonably implemented in a short-term timeframe. Can some short-term value be derived from an action with much longer-term benefits?

Resource Efficiency
One area with an obvious connection to sustainability is the efficient use of natural resources required to supplement the extraction process. Improved efficiency in the use of these resources is beneficial for both the mine, through enhanced capability for production, and the community in which they operate, through preservation of non-renewable resources.

Water is likely the most controversial resource required for mining operations. Many mining sites are located in arid desert regions where precipitation is scarce and water resources are not rapidly replenished. Expansion of existing facilities or creation of new facilities is frequently in competition with other water users due to the scarcity of water.

Mining companies have responded by modifying their processes to use less water per unit of material produced, creating an opportunity to learn and implement these practices at other facilities where they are not currently in need of water, but may be in the future. These modifications could also help reduce the cost for water treatment by reducing the volume of water that is used in mine processes.

Pristine water is not required for all processes in the mine, and mine wastewater can be treated and re-used for alternate purposes. Impacted water from mines can also be treated to provide high quality potable water as a supplement to the existing water supply of surrounding communities. This example of reuse is typically used in instances of closed mine facilities, but operational mines present a multitude of opportunities to utilize recycled water.

Frequently the mine needs to be dewatered before extraction can proceed. Aquifer re-injection has been implemented at several iron ore mines by the MWH Perth team. For aquifer re-injection, mine water is pumped back in to the aquifer to help achieve the goals of resource conservation and limiting environmental impact, while still maintaining a store of water for future use. The MWH Perth team is also now investigating the feasibility of detaining cyclonic (hurricane) run-off in catchments for longer periods to both better manage the impacts of seasonal flooding but also enhance the infiltration of recharge to the local groundwater system. These examples show opportunities where technology would help to increase the availability of water at the site, sometimes in a manner that is even more efficient than the natural system.

In some situations, other natural materials may exist at the site that could pose a hazard to the safety of mining operations, but also represent an opportunity to improve efficiency in the process. One example is when an Australian underground coal mining company found that methane was present in the underground coal seams, presenting an explosion hazard for the mine. Rather than looking at the natural methane as a burden, the company developed a power generation plant that turns methane into electricity and significantly reduces the equivalent CO2 emissions of the site. (Guerin, 2006)

On-site monitoring initiatives can focus on critical areas through the use of remote sensing.

Pumped storage facilities also can be applied to help meet energy demands during peak-use hours. By combining this technology with an operational or abandoned mine pit, this could be a powerful opportunity to utilize mine land for an alternate and possibly sustainable purpose.

Waste Management and Minimization
Waste minimization is an area with perhaps the greatest potential for improvement in mining operations, where the quantity of waste material vastly exceeds the end product, and waste management facilities represent some of the greatest liabilities at closure due to their immense size. Improved mine planning in initial stages of project development can lead to reduced costs for waste management at closure. Waste reduction is truly a winwin proposition, yielding immediate and long-term benefits.

One example is implementation of waste rock segregation programs that incorporate in-situ sampling to separate high quality material in operations. By storing this material in a location more efficient for use to cover or regrade facilities at closure, transportation costs associated with re-handling large quantities of material can be greatly reduced.

There are many opportunities to implement alternate tailings disposal techniques, and possibly create alternative uses for material previously considered to be a waste product. Minimization opportunities include methods such as reducing the volume of tailings through dewatering or dry stacking. Dry tailings also can be recycled into building materials or used as input for asphalt in paving operations.

Improving efficiency of mining methods, waste disposal practices and ore processing will improve the economic viability of extracting low grade ore from existing mine areas, thereby decreasing the area of new land disturbance. The benefit of preserving undisturbed areas combined with the increased value of precious and base metals has made reprocessing existing waste piles more attractive. This has been the case for gold tailings in the Witwatersrand, for example.

In addition to considering waste rock and tailings generated through mining activities, there are many opportunities to eliminate waste throughout the production process. One aluminum mine in Australia noticed that it was wasting a large amount of raw material by sending it to the landfill in the early years of its smelting operations. It addressed this concern by setting the goals of having no process materials going to the landfill, and zero general waste going to the landfill at the end of five years. In order to accomplish these goals, the company went back to the chemical and physical aluminum production process to determine the cause of this waste and applied technological solutions to embrace cleaner production processes. This challenge has made waste minimization an integral part of its operations, helped to reduce environmental risk, created a healthier, safer work environment and has motivated other smelters to improve their performance through similar programs. (Guerin, 2006)

Remote Sensing
Mine waste storage facilities generally represent the greatest liability at closure since they cover a very large footprint and often contain residual chemicals that could present a post-closure environmental threat. Remote sensing provides an opportunity to supplement traditional monitoring techniques that cover a limited spatial and temporal scale. As satellite information becomes more available through government programs, this data can be used for multiple purposes to look at different aspects of mine sites. Improved monitoring of these facilities could reduce costs associated with clean-up and environmental degradation resulting from leaking or improperly performing closure mechanisms. The use of remote sensing imagery can also help to focus on-site monitoring initiatives in critical areas, possibly decreasing overall monitoring costs and avoiding compounded liabilities through earlier intervention.

Sustainable approaches to mine reclamation help achieve a beneficial post-mining land use.

Opportunities for use of alternative energy can be coupled with reclamation activities as a potential post-mining land use option. The U.S. Environmental Protection Agency (EPA) Superfund Redevelopment Program (2008), for example, describes how abandoned mine lands can be ideal sites for the development of wind energy resources, because they are often located in remote, mountainous areas that receive consistent wind flows and provide large, open areas with adequate space for large-scale wind turbines. Existing infrastructure from mining operations can be incorporated into the project to help reduce startup costs. Solar energy may present similar opportunities in the future, as most mines are already connected to the grid and have key infrastructure.

Whole-System Design
One of the greatest challenges to recognizing opportunities for improvement in operations is that the focus is typically on one component of a greater system. Mining companies sometimes hire multiple engineering firms, each focusing on one element or facility and providing solutions to manage energy, water or waste resulting from that single component of the system. It is not unusual for a mining service firm to hear conflicting complaints about a shortage of water from one manager and an excess from another. We cannot consider such concepts as resource efficiency or waste management without looking at the system as a whole, and it is important for mining service companies to show their clients the benefits of that type of design.

Although this is a simple concept, whole system design is one that is commonly overlooked in engineering design. Hydraulic design is frequently finalized before the structural engineers are called in to provide insight on how to support the system. Rarely are they given the opportunity to suggest how a small change in the size of pipeline or sluice gate could lead to big savings in costs or energy for structural aspects, and vice versa. Often, one design decision is made and everything moves forward, but this should actually be an integrated process where we identify the range of options that would work for each component.

This concept is illustrated exceptionally well by Lovins et al. in their paper A Road Map for Natural Capitalism, (1999a). They cite an example where the design engineer achieved a 92% savings in power requirements through two simple design decisions; choosing larger pipes and smaller pumps than traditional design would suggest, and by laying out the pipes first and then positioning the associated pumps and equipment. Choosing larger pipes that are laid out with fewer bends reduced friction and the amount of pumping energy required. The cost for larger pipes and smaller pumps alone was cheaper than the initial design; however when the reduced cost for the required length of pipe and special fittings, reduced cost to insulate the straight pipelines, and the energy savings were included, this design change provided huge resource savings and return on investment. A whole system design approach should be used to look for opportunities to improve efficiency of resource use and mining processes, eliminate waste and minimize liabilities.

Quantifying the Benefits of Investment Opportunities
To provide a quantitative assessment of the value received by implementing different technology to improve sustainability, we need to be able to quantify the non-economic value for different investment alternatives. Current business accounting systems typically are not set up to consider intangible assets, such as human or natural capital. This makes it difficult to represent the value of concepts such as resource efficiency, if the true cost of that resource cannot be incorporated.

This is an area of on-going research, as many organizations face similar challenges. It is important that we recognize that the costs to deliver the resources do not necessarily reflect the actual value of those resources. Management consulting tools that have been developed to address all tangible and intangible organizational assets may aid in this endeavor, however they generally focus on the concept of human capital. These tools could be reworked in the future to address the concept of natural capital from a financial perspective.

Probability or range analysis also is a key tool to incorporate into our financial analyses. In many situations where we develop feasibility–level cost estimates for activities such as closure, there are huge uncertainties in individual quantities. In these situations, providing a single cost can be misleading, and by allowing a range of values for many of these quantities, a range of likely costs can be identified. There are several software packages available that integrate probabilistic analyses into a modeling framework and can facilitate the development of sustainability. This approach can provide additional insight into which tasks could greatly reduce the overall liability if addressed during operations.

The sustainability of life as it’s known on this planet cannot be addressed by the mining industry alone. But the mining industry can contribute in meaningful ways and it can have a significant positive impact on the communities in which it operates. We are leaders in efficiency and conservation of the resources we use. We continue to educate the users of the resources we provide in their efficient use and re-use. We strive to extract as much value as possible from the deposits we have access to. We consider the whole lifecycle of our product, including post-mining impacts and liabilities. We work to achieve these goals not only because it’s sustainable, but because it’s good business.

References
• Evan, L. R., and Youngs, J., 2007. Conservation of trial dewatering discharge through re-injection in the Pilbara region, Western Australia. IAH XXXV Congress – Ground-water and Ecosystems, Lisbon, Portugal.
• Guerin, T. F., 2006. A Survey of Sustainable Development Initiatives in the Australian Mining and Minerals Industry. Minerals and Energy, 3-4,11-44.
• International Council on Mining and Metals (ICMM). Sustainable Development Framework. ICMM Homepage, 2008. 20 Oct. 2008 <http://www.icmm. com/our-work/sustainable-developmentframework>.
• Lovins, A. B.; Lovins, L. H., and, P., 1999a. A Road Map for Natural Capitalism. Reprint from Harvard Business Review, Reprint Number 99309, 145-158.
• MMSD-North America, 2002. Towards Change: The Work and Results of MMSD-North America Final Report. International Institute for Sustainable Development, 88p.
• U.S. Environmental Protection Agency, 2008. A Breath of Fresh Air for America’s Abandoned Mine Lands: Alternative Energy Provides a Second Wind. Superfund Redevelopment Program, 22p.
• Youngs, J., and Brown, D. M., 2005. Aquifer re-injection as a low impact groundwater investigation tool – a case study from the Pilbara region, Western Australia. ISMAR05, Berlin, Germany.

Andrew Watson is vice president and principal engineer, MWH, Global Mining Services. For more information, visit www.mwhglobal.com