Underground Mining Methods Handbook. Hustrulid, WA, ed., New York: The American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc., 1982 Jan; :1687-1711
For a long time, the prolonged inhalation of dust has been recognized as a health hazard, leading to pulmonary diseases generally termed "pneumoconiosis." In the 16th century, Agricola, the "father of mining," discussed dust inhalation during mining. and called it a "widow maker." Quartz and asbestos particles are especially hazardous, and coal-mine dust leads to coalworker's pneumoconiosis (CWP) or "black-lung" disease. Seemingly innocuous dusts such as trona, kaolin, and limestone also are believed to involve hazards, and such dusts are termed "total dusts." The health hazard of a dust is assessed by a "threshold limit value" (TLV) assigned to the material. The TLV usually refers to an 8-hr average mass dust concentration, and it usually is defined in terms of "total" dust or "respirable" dust. Respirable dust is the fraction of the particles in the parent dust cloud that penetrates into the lungs during inhalation. The respirable fraction of the dust cloud has been variously defined by the Atomic Energy Commission (AEC) and the British Medical Research Council (BMRC). Several current TLVs include: 1) Asbestos has a TLV of 0.005 fiber/mm3 (5.0 fibers/cm3 or 82 fibers per cu in.); 2) Alpha quartz has a TLV (respirable) of 0.1 mg/m3 (0.000044 grain per cu ft); 3) Crystobalite has a TLV (respirable) of 0.05 mg/m3 (0.000022 grain per cu ft); 4) Coal-mine dust has a TLV (respirable) of 2.0 mg/m3 (0.000874 grain per cu ft); and 5) Total dust has a TLV (total) of 10.0 mg/m3 (0.004370 grain per cu ft). . Coal-mine dust also must meet the TLV for alpha quartz but, otherwise, is not defined further in terms of. Chemical composition. Revision of the TLV for alpha quartz to 0.05 mg/m3 (0.000022 grain per cu ft) currently is being considered, and revision of the TLV for asbestos to 0.002 fiber/mm3 (2.0 fibers/ cm3 or 32 fibers per cu in.) also is being considered. The health hazard associated with the inhalation of dust is not a trivial matter. CWP is the most severe health and safety problem facing the coal-mining industry today; in the United States, the number of permanent disabilities and deaths of coal miners due to CWP is 3.5 times the number of disabilities and deaths due to all other mine incidents. Similar statistics have been reported in Great Britain. The cost to government and industry for CWP compensation is approximately 1.5 billion US$ per year. The necessity of devising improved methods for mining minerals at a rapid and economical rate, while maintaining a healthful mining environment, is apparent. While some work is being conducted by the mining industries, the US Bureau of Mines (USBM) initiated an intensive research and development program in 1969, intended to provide improved and new technologies for reducing the dust in the atmospheres of both coal and non-coal mining operations. This chapter reviews the current state-of-the-art in dust-control technology, and it includes sections on personal-protection technology, dust-sampling instrumentation, and methodology. All costs herein are expressed in terms of 1977 US dollars. Although mine operators should be able to independently implement some of this technology, much of it is not in a "cookbook" status yet, and technical assistance by the USBM or others may be required to adapt a general technique to a specific situation. References herein to specific equipment or manufacturers do not imply an endorsement of the equipment or the manufacturer by the Bureau of Mines or the US Department of the Interior.