Part III. Supervision, education, and discipline-Continued.. Application of disciplinary measures. Mine safety organization.... Safety programs. Safety committees.. General Safety Committee.. Departmental Committeemen's General Safety Committee. Smelter Investigation Committee.. Branch Safety Committee... Safety and Employment Department. Accident investigations... Codes of safe practice - Systematic plant inspection. Foremanship conferences Physical examinations. Safety suggestions... References on miscellaneous accident-prevention subjects. List of miners' circulars____ ILLUSTRATIONS 1. Comfort zones for heavy work in still air. 2. Carbon monoxide recorder connected to compressed-air line in compressor room__ 3. Relation of average dust concentration and duration of dust exposure to workers having pneumoconiosis... 4. Midget impinger sampling apparatus. 5. Dust sampling with midget impinger. 10. Air-water spray at face of drift. 11. Dust-collecting system over conveyor in shaft house 12. Respirator worn by attendant at shaft-pocket ore dump 14. Change room. 15. Incorrect position for lifting. 16. Correct position for lifting 13. Boot-washing room at shaft collar. 17. Emergency dam, timbers overhead. 18. Emergency bulkhead to sealed pump room 21. Lighting in timbered haulageway . 22. Wheat electric cap lamp.... 23. Edison electric cap lamp. 24. Student miner learning to timber in instruction class. TABLES 1. Constituents of metal-mine rocks_ 2. Dust produced during work at face 4 5 8 11 12 13 14 15 15 16 17 18 23 24 26 27 35 36 42 43 44 47 48 51 61 62 3. Dust concentrations, mine and mill 4. Accidents from handling materials, underground metal-mines, 1931-43.. HEALTH AND MISCELLANEOUS HAZARDS IN METAL MINES 1 Metal-Mine Accident-Prevention Course-Section 7 INTRODUCTION PURPOSE AND SCOPE This miners' circular is the seventh of a series covering various phases of accident prevention in metal and nonmetal mines. These circulars are compiled and published with the intent that they will be a textbook for courses of instruction on accident prevention in metal mining, serving as a general reference to which may be added other material applicable to the district in which the course is presented. This section deals with health, safety organization, and other accident-prevention factors in metal mines, including supervision, education of mine bosses and miners in safe practices, illumination, and the use of goggles and protective clothing. Miscellaneous causes of accidents are also discussed; some deserve consideration because of their prevalence and others because of their interesting aspects or possible serious consequences. Other circulars in the series are: Accident Statistics as an Aid to Prevention of Accidents in Metal Mines (Miners' Circular 51); deals with general statistics on accidents in metal and nonmetal mines, including causes, costs, and the uses of investigations and reports of all accidents. Accidents from Falls of Rock or Ore in Metal Mines (Miners' Circular 52); discusses the selection of mining methods to minimize the hazard of falling ground, the uses of various types of support, and the protection of miners from falling ground. Hoisting and Haulage Accidents in Metal Mines (Miners' Circular 53); presents the hazards of hoisting and haulage and means of prevention. Explosives Accidents in Metal Mines (Miners' Circular 54); gives information on accidents due to storing, handling, and using explosives in mines and precautions by which they can be prevented. Fires, Gases, and Ventilation in Metal Mines (Miners' Circular 55); explains causes of mine fires and the measures used to prevent them, describes gases found in mines and methods of detection, and discusses necessity for and standards of proper ventilation. Electrical and Mechanical Hazards in Metal Mines (Miners' Circular 56); covers accidents from these causes and their prevention. Accidents from falls of persons are also discussed in this section. These seven miners' circulars do not contain all the material that may be desired on any of the various phases of accident prevention in metal 1 Work on manuscript completed February 1946. mines, but it is hoped that they will be inclusive enough to serve as a basis for discussions. To these may be added supplementary material of particular interest in the field where the course is being presented. ACKNOWLEDGMENTS Accident statistics and charts in this circular were prepared with the assistance of W. W. Adams and F. J. Kennedy of the Accident Analysis Division of the Bureau. Drawings, charts, and photographs for the illustrations were prepared through the assistance of L. F. Perry and G. L. Henneman of the Graphic Section of the Office of Minerals Reports of the Bureau. S. J. Davenport and D. O. Kennedy reviewed the manuscript of the circular and gave many valuable suggestions. HEALTH HAZARDS OF METAL MINERS Although industrial hygiene in the field of public health work is a comparatively recent development, it is rapidly increasing in importance as appreciation grows of the responsibility to provide working conditions for industrial employees that are safe from danger to health as well as from chances of injury. The purpose of industrial hygiene services is the protection of health, the improvement of efficiency, and the prolongation of life of workers. Although the recognition of occupational diseases, as such, dates back to ancient times, the growth of remedial measures has been slow up to recent times. Intensive efforts to determine health hazards and to eradicate them or supply protective methods are now seen in all industries. Health hazards in mining are being investigated and gradually reduced or eliminated by the mine operators, State and Federal Public Health Services, and the Bureau of Mines. Reasons for the attention given this subject in recent years are the desire to improve efficiency and economy of operation, promote higher standards of health and living, and secure the enactment of compensation laws that cover disability from occupational disease. In addition, great strides have been made in the development of instruments for accurate study and control of conditions causing occupational diseases. Extensive research work and clinical and laboratory studies have definitely fixed the toxic threshold or maximum safe concentrations of many of the potentially harmful materials encountered in industry. Disbelief may be the general attitude of mining men when told that occupational diseases take a greater toll in money, as well as in health, than do accidents, but the fact can be demonstrated for industry in general and the situation in mining or a mining field will certainly bear investigation. The efficiency of a worker suffering from an occupational disease or an unrelated illness is diminished long before he reaches the point where he is unable to work or is awarded compensation. Absenteeism in mining caused by illness can only be estimated, and the proportion of this lost time due to occupational disease or illness is also undetermined. Neither accurate figures nor reliable estimates are obtainable on the total costs of occupational health hazards in the mining industry, but attempts to estimate the costs show that, in general, they are much greater than those from accidents. Factors that should be included in such an estimate are time lost through sickness, inefficiency of affected workers on the job, accidents due wholly or in part to illness of workers, compensation, and medical care of disabled workers. Dr. R. R. Sayers, Director of the Bureau of Mines, stated in an address at Charleston, W. Va., in 1945 that the experience of the St. Joseph Lead Co. affords an example of the practical value of improving living and working conditions at mines. Improvements in living conditions included housing, water and food supply, sanitation, schools, and recreation. Particular attention was given to community health. The occupational hazards to health at the mines were surveyed, and steps were taken to remove or control them. As a result, the labor turn-over was reduced in a few years from 250 to 3.6 percent, with an annual saving of about $250,000 for hiring and training new employees and about $40,000 for accidents. Accounts were not kept of costs directly chargeable to health hazards. Daniel Harrington, chief of the Health and Safety Branch, Bureau of Mines, summarized many years' study of the problems as follows:2 Health is probably of greater value to the miner than to most people as his occupation almost invariably demands the possession of far more than ordinary physical abilities. When his health fails, he is usually relegated to the scrap heap. The miner has numerous advantages, as well as some very definite disadvantages, as regards health, in comparison with persons engaged in other types of industrial endeavor. Practically all miners are forced to take considerable amounts of exercise; in general, the mine worker, in reasonably well-conducted mines, has almost ideal conditions in his working place as to temperature and humidity. There are, however, exceptions, Many deep mines have high temperatures, others have both high temperatures and high humidities, and open or shallow mines are exposed to extreme changes of weather. AIR TEMPERATURE AND HUMIDITY Working under conditions of high temperature and high humidity is enervating and decreases the efficiency of workers as well as making them more susceptible to disease. These effects and the relationship of abnormal atmospheric conditions are discussed in Miners' Circular 55, page 82. Studies of human comfort in relation to temperature and humidity, which were made by the American Society of Heating and Ventilating Engineers in cooperation with the Bureau of Mines and the Federal Public Health Service, showed that the best working conditions were between 50° and 75° F., with the humidity between 20 and 95 percent. The limiting conditions are shown by the chart, figure 1. The zones of comfort and discomfort shown by this chart are for heavy work in still air; movement causes the air to feel cooler because of the better transfer of heat from the body to the surrounding atmosphere. When the rate of transfer is too slow or too fast, the body temperature is raised or lowered to the point of discomfort. Under extreme conditions weakness may be produced with impairment of breathing and pulse. 2 Harrington, D., The Miner's Health: Nat. Safety News, October 1933, p. 82. 3 Sayers, R. R., and Davenport, Sara J., Review of Literature on the Physiological Effects of Abnormal Temperatures and Humidities: U. S. Pub. Health Repts. Repr. 1150, 1927, 63 pp. |