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Evolutionary and Revolutionary Technologies for Mining Executive Summary The Office of Industrial Technologies (OIT) of the U. S. Department of Energy commissioned the National Research Council (NRC) to undertake a study on required technologies for the Mining Industries of the Future Program to complement information provided to the program by the National Mining Association. Subsequently, the National Institute for Occupational Safety and Health also became a sponsor of this study, and the Statement of Task was expanded to include health and safety. The NRC formed a multidisciplinary committee of 14 experts (biographical information on committee members is provided in Appendix A) from academia, industry, state governments, and national laboratories. Committee members have recognized expertise in exploration geology and geophysics; mining practices and processes for coal, minerals, and metals; process engineering; resource economics; the environmental impacts of mining; mineral and metal extraction and processing technologies; and health and safety. The overall objectives of this study are: (a) to review available information on the U.S. mining industry; (b) to identify critical research and development needs related to the exploration, mining, and processing of coal, minerals, and metals; and (c) to examine the federal contribution to research and development in mining processes. Seven specific tasks are outlined below. Review the importance to the U.S. economy (in terms of production and employment) of the mining industries, including the extraction and primary processing of coal, minerals, and metals. Identify research opportunities and technology areas where advances could improve the effectiveness and increase the productivity of exploration. Identify research opportunities and technology areas where advances could improve energy efficiency, increase productivity, and reduce wastes from mining and processing. Review the federal research and technology resources currently available to the U.S. mining industry. Identify potential safety and health risks and benefits of implementing identified new technologies in the mining industries. Identify potential environmental risks and benefits of implementing identified new technologies in the mining industries. Recommend objectives for research and development in mining and processing that are consistent with the goals of the Mining Industry of the Future Program through its government-industry partnership. To address this charge the committee held six meetings between March and October 2000. These meetings included presentations by and discussions with the sponsors, personnel from other government programs, and representatives of industry and academia. Individuals who provided the committee with oral or written input are identified in Appendix B. As background material, the committee reviewed relevant government documents and materials, pertinent NRC reports, and other technical reports and literature published through October 2000. This report is intended for multiple audiences: the Office of Industrial Technologies, the National Institute for Occupational Safety and Health, policy makers, scientists, engineers, and industry associations. Chapter 1 provides background material. Chapter 2 provides an overview of the economic importance of mining and the current state of technology (Task 1). Chapter 3 identifies technologies that would benefit major components of the industry in the areas of exploration, mining, and processing (Tasks 2 and 3). Chapters 4 and 5 identify technologies relevant to health and safety and to the environment, respectively (Tasks 5 and 6). Health, safety, and environmental risks and benefits of individual technologies are also interwoven in the discussions in Chapter 3. Chapter 6 describes current activities in federal
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Evolutionary and Revolutionary Technologies for Mining government agencies that could be applied to the mining sector (Task 4). Chapter 7 discusses the need for federally sponsored research and development in mining technologies. Chapter 8 summarizes the committee’s conclusions and recommendations (Task 7). IMPORTANCE OF MINING TO THE U.S. ECONOMY Finding. Mining produces three types of mineral commodities—metals, industrial minerals, and fuels—that all countries find essential for maintaining and improving their standards of living. Mining provides critical needs in times of war or national emergency. The United States is both a major consumer and a major producer of mineral commodities, and the U.S. economy could not function without minerals and the products made from them. In states and regions where mining is concentrated this industry plays an important role in the local economy. TECHNOLOGIES IN EXPLORATION, MINING, AND PROCESSING Mining involves a full life cycle from exploration through production to closure with provisions for potential postmining land use. The development of new technologies benefits every major component of the mineral industries: exploration, mining (physical extraction of the material from the Earth), processing, associated health and safety issues, and environmental issues. The committee recommends that research and development be focused on technology areas critical for exploration, mining, in-situ mining, processing, health and safety, and environmental protection. These technology areas are listed in Table ES-1 and are summarized below. Exploration Modern mineral exploration is largely technology driven. Many mineral discoveries since the 1950s can be attributed to geophysical and geochemical technologies developed by both industry and government. Further research in geological sciences, geophysical and geochemical methods, and drilling technologies could increase the effectiveness and productivity of mineral exploration. Because many of these areas overlap, developments in one area will most likely cross-fertilize research and development in other areas. In addition, many existing technologies in other fields could be adapted for use in mineral exploration. Technological development, primarily miniaturization in drilling technologies and analytical tools, could dramatically improve the efficiency of exploration, as well as aid in the mining process. At the beginning of the twenty-first century, even as the U.S. mining industry is setting impressive records in underground and surface mine production, productivity, and health and safety in all mining sectors (metal, industrial minerals, and coal), major technological needs have still not been met. Continued government support for spaceborne remote sensing, particularly hyperspectral systems, will be necessary to ensure that this technology is developed to a stage that warrants commercialization. In the field of geological sciences, increasing support of basic science, including support for geological mapping and geochemical research, would provide a significant, though gradual, increase in the effectiveness of mineral exploration. Filling the gaps in fundamental knowledge, including thermodynamic-kinetic data and detailed four-dimensional geological frameworks of ore systems, would aid mineral exploration and development, as well as mining and mineral processing. Focused research on the development of exploration models, particularly for “environmentally friendly” ore deposits, could yield important beneficial results in the short term. If attention were focused on the most important problems, as identified by industry, the effectiveness of research would be greatly increased. Mining In simple terms, mining involves breaking apart in-situ materials and hauling the broken materials out of the mine, while ensuring the health and safety of miners and the economic viability of the operation. A relentless search has been under way since the early 1900s for new and innovative mining technologies that would improve health and safety and increase productivity. In recent decades another driver has been a growing awareness of the adverse environmental and ecological impacts of mining. Although industry currently supports the development of most new geochemical and geophysical technologies, basic research, such as determining the chemistry, biology, and spectral character of soils, would significantly benefit the minerals industry. For example, uncertainty about rock stability and gas and water conditions that will be encountered during underground mining impedes rapid advances and creates health and safety hazards. As mining progresses to greater depths, increases in rock stress require innovative designs to ensure the short-term and long-term stability of the mine structure. Truly continuous mining will require an accelerated search for innovative fragmentation and material-handling systems. Sensing, analyzing, and communicating data and information will become increasingly important. Mining environments present unique challenges to the design and operation of equipment, which must be extremely reliable. Increasing the productive operating time of equipment and mining systems will require innovative maintenance strategies, supported by modern monitoring technologies. Substantial research and development opportunities could be investigated in support of both surface and underground mining. The entire mining system—rock fracturing, material handling, ground support, equipment utilization, and maintenance—would benefit from research and development in many sectors. However, focus should be primarily in four
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Evolutionary and Revolutionary Technologies for Mining TABLE ES-1 Key Research and Development Needs for the Mining Industries Research and Development Needs Exploration, Chapter 3a Mining, Chapter 3a In-Situ, Chapter 3a Processing, Chapter 3a Health & Safety, Chapter 4a Environmental Protection, Chapter 5a Basic Research Basic chemistry – thermodynamic and kinetic data, electrochemistry X X X X Fracture processes – physics of fracturing, mineralogical complexities, etc. X X X Geological, geohydrological, geochemical, and environmental models of ore deposits X X X X Biomedical, biochemical, and biophysical Sciences X X X X X X Applied Research Characterization – geology (including geologic maps), hydrology, process mineralogy, rock properties, soils, cross-borehole techniques, etc. X X X X X X Fracture processes – drilling, blasting, excavation, comminution (including rock-fracturing and rubblization techniques for in-situ leaching and borehole mining) X X X X Modeling and visualization – virtual reality for training, engineering systems, fluid flow X X X X X X Development of new chemical reagents and microbiological agents for mining-related applications (such as flotation, dissolution of minerals, grinding, classification, and dewatering) X X Biomedical, biochemical, and biophysical sciences X X X X Water treatment X Closure X X Alternatives to phosphogypsum production and management X Technology Development Sensors – analytical (chemical and mineralogical; hand-held and down-hole), Geophysical (including airplane drones, shallow seismic data, and hyperspectral data), surface features, personal health and safety, etc. X X X X X X Communications and monitoring X X X X Autonomous mining X X Total resource recovery without environmental impact X X X X Fine and ultrafine mineral recovery (including solid-liquid separation, recovery of ultrafine particles, disposal) X X X In-situ technologies for low-permeability ores directional drilling, drilling efficiencies, casing for greater depths) (includes some of the technologies under fracture processes as well as X X X Biomining X X X Fracture processes – applications of petroleum and geothermal drilling Technologies to mining X X X aJustification for including these research and development needs are found in the following chapters indicated. key areas: (1) fracture, fragmentation, and cutting with the goal of achieving continuous mining (while conserving overall energy consumption); (2) sensors and sensor systems for mechanical, chemical, and hydrological applications; (3) data processing and visualization methods that produce real-time feedback; and (4) automation and control systems. In-Situ Mining In-situ mining is the removal of a mineral deposit without physically extracting the rock. In-situ leaching is a type of in-situ mining in which metals are leached from rocks by aqueous solutions, a hydrometallurgical process. There are many opportunities for research and technology development related to in-situ mining and related approaches to direct extraction. The chief hurdle to using in-situ leaching with more types of mineral deposits is the permeability of the ore body. Technologies that would fracture and rubblize ore so that fluids would preferentially flow through the ore body and dissolve ore-bearing minerals are a high priority. For some commodities, such as phosphate rock and coal, the removal of the entire mass without dissolving specific minerals through bore-hole mining may be a promising approach. Key environmental and health concerns related to in-situ leaching are bringing potentially toxic elements or lixiviants to the surface or mobilizing them into groundwater. The development of lixiviants and microbiological agents that
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Evolutionary and Revolutionary Technologies for Mining could selectively dissolve the desired elements and leave the undesired elements in the rock would be extremely beneficial. The closure of in-situ leaching facilities raises additional environmental concerns. Therefore, research that would increase the overall availability and effectiveness of in-situ mining technologies should also include evaluations of how these facilities could be closed without impacting the long-term quality of groundwater. Processing Mineral processing encompasses unit processes for sizing, separating and processing minerals, including comminution, sizing, separation, dewatering, and hydrometallurgical or chemical processing. Research and development would benefit mineral processing in the metal, coal, and industrial mineral sectors. Every unit process—comminution (pulverization), physical separation, and hydrometallurgy/chemical processing—could benefit from technological advances, ranging from a better understanding of fundamental principles to the development of new devices and the integration of entire systems. Because comminution is extremely energy intensive, the industry would significantly profit from technologies that enhance the efficiency of comminution (e.g., new blasting and ore-handling schemes) and selectively liberate and size minerals. Areas for research include fine-particle technologies, from improved production methods for the ultra-fine grinding of minerals to the minimization of fine-particle production in coal preparation, and the monitoring and controlling of properties of fine particles. Technology needs in physical separation processes are focused mainly on minimizing entrained water in disposable solids, devising improved magnetic and electrical separators, developing better ore-sorting methods, and investigating selective flocculation applications. Although flotation is a well developed technology, the mining industry would benefit from the availability of more versatile and economic flotation reagents, on-stream analyses, and new cell configurations. The most important transformation of the mineral industry in the next 20 years could be the complete replacement of smelting by the hydrometallurgical processing of base metals. For this to happen, the trend that began with dump and heap leaching coupled with solvent extraction/ electrowinning and that was followed by bioleaching and pressure oxidation would have to be accelerated. Future research and development should be focused on innovative reactor designs and materials, sensors, modeling and simulation, high-pressure and biological basics, leaching, and metal-separation reagents. HEALTH AND SAFETY RISKS AND BENEFITS Several factors have contributed to improvements in the overall safety conditions in mines. The U.S. Bureau of Mines (whose health and safety function is now partly handled by the National Institute of Occupational Safety and Health) and industry have conducted pioneering research on hazards identification and control. Other factors are major improvements in mine design, the passage of stringent health and safety regulations, and the introduction of more productive systems. Although the frequency of major disasters has been reduced, death and disabling injuries caused by machinery, roof falls, and electrical accidents continue to occur, and are a major concern. On the health front, miners have long been aware of the hazards posed by the gases, dusts, chemicals, and noise encountered in the work environment and in working under conditions of extreme temperatures (hot or cold) and high altitudes. Although progress has been made, occurrences of silicosis, pneumoconiosis (black lung disease), occupational hearing loss, and other health problems have long been associated with and continue to occur in mining operations. Much remains to be accomplished to make the mine environment healthier. The committee examined the risks and benefits associated with the introduction of new technologies in terms of equipment size, automation, ergonomics, alternate power sources, noise, communications, and training. Relatively new technologies, such as in-situ mining, better designed equipment, and automation, have reduced exposures to traditional hazards. As production and productivity increase with the increasing size of equipment, exposures to health and safety threats are decreased. At the same time, these advancements may introduce new hazards and in some cases may exacerbate known hazards. Developing the knowledge and skills through education and training to recognize and overcome threats to health and safety during both the design and operational stages of a system is critical. New monitoring and control systems could effectively address issues related to mining equipment and mine system safety. Advances in industrial training technology have immense potential for improving miner training. Most of these advancements could be realized through combinations of sensors, analyses, visualizations, and communication tools that would enable miners to eliminate hazards altogether or enable them to take steps to avoid an emerging hazard. Finding. Advances in technology have greatly enhanced the health and safety of miners. However, potential health hazards arising from the introduction of new technologies, which may not become evident immediately, must be addressed as soon as they are identified. RESEARCH OPPORTUNITIES IN ENVIRONMENTAL TECHNOLOGIES The mining of coal, base and precious metals, and industrial minerals raises several environmental issues. Some are common to all of these sectors; others are specific to one
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Evolutionary and Revolutionary Technologies for Mining sector, or even to one commodity within a sector. The creation of large-scale surface disturbances, the production of large volumes of waste materials, and exposures of previously buried geologic materials to the effects of oxidation are intrinsic to the mining industry and continue to present complex environmental problems even when the best available practices are conscientiously followed. Research options that would provide the greatest environmental benefits for the mining industry would focus primarily on protecting surface and groundwater quality. The most urgent needs are for accurate, real-time methods of characterizing the potential of waste materials that generate acid rock drainage and improved techniques for managing these wastes. Research is also needed to further develop and optimize treatment technologies for acid rock drainage, such as biologic reduction, and to address issues associated with the creation of pit lakes. Improved technologies are also necessary for managing nonacidic wastewaters, including the development of effective, low-cost techniques for removing low concentrations of elements, such as selenium, from large volume flows and removing nitrates from wastewater discharges. Beneficial research could also be focused on techniques to enhance the long-term environmental stability of closed dump and heap-leaching operations and tailings impoundments. Areas for research include the dewatering of phosphate slimes and other slurried mine wastes, as well as the long-term stability of disposal units for these wastes. Better techniques of recovering methane from underground coal mines would provide significant environmental, health, safety, and economic benefits. Research on technologies to control the emission of fine particulates is also needed. Finding. The need for a better understanding of the scientific underpinnings of environmental issues and for technologies to address them effectively cannot be overemphasized. Recommendation. Technologies that attempt to predict, prevent, mitigate, or treat environmental problems will be increasingly important to the economic viability of the mining industry. Improved environmental technologies related to mine closures present the greatest opportunity for increasing productivity and saving energy. Research is also needed on water quality issues related to mine closures, which are often challenging and costly to address for all types of mining. ROLE OF THE FEDERAL GOVERNMENT Successful research and development has led to new technologies that have reduced production costs; enhanced the quality of existing mineral commodities; reduced adverse environmental, health, and safety impacts; and created or made available entirely new mineral commodities. Consumers, producers, and the economies of neighboring communities are likely to benefit from the results of further research and development. Mining companies that would benefit from research and development in exploration, mining, and mineral processing presumably have an incentive to pay for some of the costs. The major concern for public policy, however, is that in commercial firms, areas for research and development are selected based on benefits expected to be captured. The external benefits (i.e., benefits realized by consumers and other producers) of research and development often constitute a large portion of the total benefits. Government funding for basic research is a dominant factor, and its role in applied research and technology development is significant (NRC, 1995c). Funding for basic research and long-term technology development also leads to benefits for other industries. If funding also involves universities, it can support the training of scientists and engineers (including industry and government professionals, researchers, and trainers of the next generation of employees) who will benefit the mining industry, as well as other technology-intensive sectors of the economy. Finding. The market will not support an optimal amount of research and development, possibly by a wide margin. Without government support, the private sector tends to underfund research and development, particularly high-risk projects with long-term payoffs. Finding. Although research in a broad range of fields may eventually have beneficial effects for the mining industry, the committee identified a number of areas in which new basic scientific data or technology would be particularly beneficial (Table ES-1). Recommendation. The federal government has an appropriate, clear, and necessary role to play in funding research and development on mining technologies. The government should have a particularly strong interest in what is sometimes referred to as high-risk, “far-out,” “off-the-path,” or “blue-sky” research. A portion of the federal funding for basic research and long-term development should be devoted to achieving revolutionary advances with the potential to provide substantial benefits to both the mining industry and the public. AVAILABLE FEDERAL RESOURCES For more than a century the federal government has been involved in research and development for basic industries. In addition, many federal agencies are involved in science, engineering, and technology development that could be useful to the mining industry. Many federal research and development programs dealing with
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Evolutionary and Revolutionary Technologies for Mining transportation, excavation, basic chemical processes, novel materials, and other subjects could ultimately be beneficial to the mining industry. The only active federal program that deals solely with the development of more efficient and environmentally benign mining technologies is the Mining Industries of the Future Program of the Office of Industrial Technologies of the U.S. Department of Energy. Finding. The committee recognizes that federal agencies undertake worthwhile research and development for their own purposes. Research and development that could benefit the mining sector of the U.S. economy is being pursued by many federal agencies. The problem is not the lack of skilled researchers but the lack of direct focus on the problems of most interest to the mining industry. It would be helpful if progress in these programs were systematically communicated to all interested parties, including the mining sector. Recommendation. Because it may be difficult for a single federal agency to coordinate the transfer of research results and technology to the mining sector, a coordinating body or bodies should be established to facilitate the transfer of appropriate, federally funded technology to the mining sector. The Office of Industrial Technologies has made some progress in this regard by organizing a meeting of agencies involved in research that could benefit the mining industry. Office of Industrial Technology Mining Industries of the Future Program The OIT has adopted a consortia approach in its Industries of the Future Program, a model that has proved to be extremely successful (NRC, 1997). The Mining Industries of the Future Program is subject to management and oversight by the U.S. Department of Energy and receives guidance from the National Mining Association and its Technology Committee. The NRC’s Committee on Technologies for the Mining Industries recognizes that the research and technology needs of the mining industry draw upon many disciplines, ranging from basic sciences to applied health, safety, and environmental sciences. Recommendation. Consortia are a preferred way of leveraging expertise and technical inputs to the mining sector, and the consortia approach should be continued wherever appropriate. Advice from experts in diverse fields would be helpful for directing federal investments in research and development for the mining sector. Consortia should include universities, suppliers, national laboratories, any ad hoc groups considered to be helpful, government entities, and the mining industry. The Office of Industrial Technologies should institute periodic, independent program reviews of the Mining Industries of the Future Program to assure that industry needs are being addressed appropriately.
Representative terms from entire chapter: