Health and Safety Risks and Benefits
Chapter 3 identified technologies that will benefit major components of the industry in the areas of exploration, mining, and processing. This chapter discusses concerns for potential new health hazards arising from the introduction of new technology.
At the beginning of the twentieth century approximately 3,000 coal miners and 1,000 metal/nonmetal workers were killed annually in mine accidents (Ramani and Mutmansky, 2000). In 1910 the U.S. Congress created the USBM in the U.S. Department of the Interior to conduct research on the health and safety problems associated with the extraction and processing of coal and minerals. Since that time, overall safety conditions in mines have improved as a result of several factors, including the pioneering research by the USBM on hazards identification and control, major improvements in mine design, the passage of stringent health and safety legislation, and the introduction of more productive systems. Cooperative efforts on the part of industry and the USBM led to advances in mining sciences and technology that dramatically reduced deaths and injury-causing accidents (Figures 4-1 and 4-2) (Ramani and Mutmansky, 2000).
The declining trends in fatal and nonfatal incidents have continued to this day (Figures 4-3 and 4-4). Major changes that have influenced these trends are the prevalence of surface mining, larger mining equipment and record setting mine production and productivity rates (Adamczyk, 2000; Phelps, 2000; Ramani and Mutmansky, 2000; Carter, 1999; Shuey, 1999; Wheeler and Walls, 1998; Hartman, 1987).
In the last three decades, industry-specific health and safety legislation has progressed from the state level to the federal level. The 1969 Coal Mine Health and Safety Act and the 1977 Mine Safety and Health Act were landmark laws that brought significant advances in mine health and safety. As a consequence, at the end of the twentieth century, yearly coal mine fatalities had dropped to one-sixtieth, and metal/nonmetal mine fatalities to one-twentieth of the rates at the beginning of the century; at the same time, production today dwarfs production then.
According to the National Safety Council statistics of selected industries, safety in the mining industry is near the top one-third of industries reported (National Safety Council, 1999). Major disasters have been effectively controlled, although death and disabling injuries continue to occur from machinery, roof falls, and electrical accidents. Nevertheless, the fact that fatalities and injuries continue to occur is a cause for concern.
On the health front, miners have long been aware of the hazards posed by the gases, dusts, chemicals, and noise in the work environment and in working in extreme temperatures (hot or cold) and at high altitudes. Silicosis, pneumoconiosis (black lung disease), occupational hearing loss, and other medical problems have long been associated with mining operations. The 1969 Coal Act established, for the first time, stringent requirements for the control of airborne, respirable coal-mine dust as a means of reducing incidences of pneumoconiosis and silicosis, and major reductions have been made in airborne, respirable dust concentrations in underground coal mines (Figure 4-5).
Although health conditions in coal mines have improved considerably since 1969, new cases (almost 150 in 1999) of these lung diseases are still being reported (U.S. Department of Labor, 2000b). At the present time, about 40,000 former miners are disabled from lung diseases, such as black lung disease and silicosis (U.S. Department of Labor, 2000b). Potential health hazards introduced by new technologies must be addressed proactively because they may not be immediately apparent. For example, the use of diesel equipment in the mine environment has raised concerns because of the presence of other contaminants in the mine atmosphere.
Chemical and biological hazards must also be given more attention. The use of chemicals in many areas of mining, particularly in hydrometallurgy and in-situ leaching, is also increasing. The introduction of new lixivants in hydrometallurgy and bioagents to facilitate the leaching of metals may create new health and safety hazards.
SIZE OF EQUIPMENT
One technological trend in the mining industry is the steady increase in the size of mining equipment. As the level of automation increases, large machines may be able to operate in a fully automated mode (Shuey, 1999). Larger equipment will certainly decrease individual exposures to hazardous conditions in the mine environment. However, they will also introduce new problems. For example, the increasing size of mobile mining machinery, particularly large hauling equipment, has increased the likelihood of accidents by decreasing all-around visibility for the operator. If the operator does not know his precise location in the mine, near a berm or where nearby objects, such as other miners and smaller equipment are, fatal and costly accidents can result. Technology that can alert equipment operators to the presence of obstructions (e.g., other equipment, berms, miners) and their relative distances would mitigate this problem. In addition to the extensive use of closed-circuit television, automatic control of the equipment, aided by onboard sensors and GPS monitors, could reduce these hazards.
Several mining systems (e.g., longwall systems in underground coal mining) are already highly automated. Semiautonomous and fully autonomous systems can result in higher levels of production and productivity, as well as better health and safety conditions. However, automated equipment, even remotely controlled equipment, can create new hazards. Because the number of automated systems in the mining industry is small, no extensive data on health and safety are available. However, it is known that automation has been responsible for a small number of mine accidents involving deaths and disabling injuries (NIOSH, 1999).
Automated equipment is also subject to unexpected or unplanned movements. Unique challenges presented by the mining environment to the designer and operator of automated equipment include the lack of precise knowledge of operating conditions, mostly because of variations in geology; a demanding operating environment exacerbated by extremely dusty, noisy, and vibrational conditions; specialized equipment design to meet the stringent
safety standards required to operate in mines; and more rigorous maintenance programs for proper operation. Research could focus on understanding the design specifications for automated operation in the mining environment and ensuring the robustness and reliability of equipment and systems. At the same time, new training programs will be necessary to address new hazards. Virtual reality systems for training miners and operators would be useful.
Back injuries, especially strains, are common among miners (NIOSH, 2000). As thinner seams and narrower veins are mined, new technologies and more ergonomic designs will be necessary to reduce the number of injuries and to enable workers to operate in confined, awkward spaces. Workplace risk factors that lead to musculoskeletal disorders (e.g., low back pain) should be identified and taken into account in the design of equipment and training programs. Remote control and autonomous operation would eliminate the problem.
ALTERNATIVE POWER SOURCES
Alternative power sources are being explored for mining for increasing the efficiency of production systems and reducing hazards from electrical power. Although hydrogen-powered vehicles are under development, the use of diesel-powered equipment has been on the rise. The benefits of research on cleaner, more efficient diesel engines for other applications (e.g., surface highway vehicles) will be useful to mining equipment manufacturers.
Safe operation of diesel-powered equipment in mines is affected by the gas, dust, visibility, vibrations, noise, and degree of confinement. The impact on the health and safety of miners requires research on a number of fronts: the development of monitoring equipment that can discriminate among the sources of airborne pollutants (blasting, diesels, oxidation, cutting, etc.) and an instrument that can reliably measure the amount of particulates in the mine. A related need is for accurate, real-time monitors of personal exposure. For example, a device that indicates in real time the level of a miner’s exposure to respirable coal-mine dust (personal exposure) will be essential to controlling excessive exposures. Another area for study is health effects of mixed-mode exposures to mineralogical constituents of the mined materials and particulates in diesel exhaust.
Audiometric data on coal and metal/nonmetal miners shows that noise-induced hearing loss in miners has become a substantial problem (U.S. Department of Labor, 1999). The Mine Safety and Health Administration (MSHA) recently issued the final rule for occupational noise exposure. Risk of hearing loss for an individual increases with the level of noise and the duration of the exposure. Minimizing the risk of hearing loss must be an essential aspect of new technology development. Research should focus on the development of materials that reduce noise levels (source control) and remote, automatic control technology for noisy mining equipment. Training miners in safe operating procedures in a noisy environment and the correct use of personal noise protection devices will also be necessary.
Research linking computer-oriented monitoring of conditions in mines with a safety information system and a rapid communication system for transmitting that information in real time to miners could have tremendous payoffs for the entire industry. As equipment and mining systems become increasingly automated, miners may not be working in close proximity or in visual contact with each other. In fact, most miners may be in remote areas of the mine. Therefore, the need to communicate with each miner, based on real-time data and analyses, will be critical. Some components, such as atmosphere-monitoring systems, equipment-monitoring systems, and pager systems, have already been developed. These advancements must now be integrated so specific, immediate safety information and instructions can be communicated to individual miners.
Any change in the mining system — a new environment, new equipment, new rules, or new personnel—requires that miners be trained to accommodate it. Mandatory health and safety training would be greatly improved by computer-oriented training tools and techniques for miners and supervisors. Computer-based training would use the capabilities of computers to overcome some of the limitations of traditional classroom and on-the-job training programs. Computer-based training would also promote better designed and higher quality lessons and self-learning. Virtual-reality training modules would improve miners’ ability to react appropriately to hazardous situations.
Advances in technology have historically improved the health and safety of miners. Relatively new technologies, such as in-situ mining and automation, can significantly reduce exposures to traditional mine hazards. Increasing production and productivity with larger equipment can also
TABLE 4-1 Recommendations for Research and Development in Health and Safety
• technology to alert equipment operators of the existence and location of obstructions (such as equipment, berms, miners)
• design specifications for automated operation in the mining environment that enhance robustness and reliability
• miner-training programs to address special hazards that are created by the introduction of automated systems
• identification and elimination of workplace hazards introduced by new chemicals and bioagents
• identification of workplace risk factors that lead to musculoskeletal disorders (e.g., low back pain) and the design of equipment and training programs to eliminate them
• technology for assessing health and safety conditions in mine atmospheres; monitoring equipment that can distinguish the sources of airborne pollutants (blasting, diesels, oxidation, cutting); an instrument that can reliably measure the amount of diesel particulate matter; instruments that can accurately measure real-time personal exposures, particularly exposures to airborne respirable coal-mine dust
• determination of the health effects of mixed mode exposures in mine environments
• new materials and technologies to reduce noise in mining equipment and systems
• linking of computer-oriented monitoring of conditions in mines with a safety information system and a rapid communication system to provide specific information in real-time to each miner
• virtual-reality training modules for miners and mining-equipment operators
reduce exposures to health and safety threats. At the same time, these advancements will certainly introduce new hazards and, in some cases, may exacerbate known hazards.
New monitoring and control systems could effectively address the mining-equipment and mine-system safety issues. Advances in industrial training technologies, for example, have immense potential for improving safety. Most of these advancements would be realized through intelligent combinations of sensors, analyses, visualization, and communication tools that will either eliminate a hazard or enable a miner to take rapid actions to avoid an emerging hazard. Several areas for research and development are identified in Table 4-1.