752 RADIATION PROTECTION Other Safety and Health Recommendations Fortunately, small operations can accomplish results in accident prevention corresponding to those at large operations with a complex program. Two ingredients are essential at both large and small mines competent supervision and a sincere belief in safety and safety education of employees. A competent supervisor is difficult to obtain where pay is low, future operations uncertain, and living conditions poor. Nevertheless, a competent supervisor who believes in accident prevention is essential for safe, efficient operation. The money spent to retain such an individual is an intelligent investment. Safety education should instill a desire to work safely in the minds of the employees and teach them how to work safely. Competent supervision will then require that the work be done in a safe manner. Employees may be educated in safety at little expense. Their immediate supervisors, through day-to-day contacts, have an excellent opportunity to instruct employees in safe working methods. Setting a good example is still a good method of teaching a new man, whether the good example is set by the supervisor or an experienced fellow worker. First-aid training is a good way to begin safety instructions. A course in first-aid training will show employees the consequences of an unsafe act, and frequently will produce immediate improvement in the accident rate. First-aid training has an additional advantage of teaching employees to care for their injured fellow workers. This training is doubly valuable in isolated locations. The Bureau of Mines also offers a metal-mine accident-prevention course that treats more specifically with the hazards and problems of a particular property. Both courses are available through the Federal Bureau of Mines. Inexperienced miners have been found working in isolated mines or remote parts of mines with little or no supervision. Even experienced miners need dayto-day supervision and discussions with an experienced supervisor to maintain safe working habits and make efficient progress. Inexperienced men have even greater need of guidance and adequate training if they are to develop into safety-conscious employees. Much makeshift equipment has been observed in uranium mines, sometimes because it is difficult to repair or replace equipment owing to the isolation of the mine and sometimes because expenditures for equipment must be kept at a minimum. Certainly, where human life is at stake, expenditures should be adequate to afford safe working conditions. Following expediency in repairing or replacing equipment too often has caused needless injuries, resulting in a high frequency and severity of accidental injuries. General carelessness in storing and handling explosives also has been noted. In isolated places, realization of the need for safe storage is probably dulled, but accidents from explosives have injured people not directly connected with the mining operation, even in the far reaches of the Navajo Reservation. Safe storage should always be provided for explosives. Both carelessness and inexperience have caused explosives accidents in uranium mines. Miners must be instructed in the safe use of explosives and given enough supervision to see that these safe methods are followed. RADIATION PROTECTION 753 As there are potentially dangerous gaps in our knowledge of the effects on health of a combination of hazards in uranium mines, all recommended measures should be strictly followed, including the use of respiratory protective equipment, personal cleanliness, proper nutrition, periodic physical examinations, and chest X-rays. FIELD METHOD FOR SAMPLING AND DETERMINING Relatively simple and inexpensive equipment has now been designed and tested in the field for sampling and determining atmospheric concentrations of radon daughters. Filter paper, a filter holder, a small hand-cranked or battery-operated pump, and a calibrated alpha survey meter are the only equipment needed. The method follows: 1. Draw a known quantity of mine atmosphere (14 to 23 liters per minute) through a hand-cranked vacuum pump or other suitable air-moving device for either a 5- or 10-minute period. The sampling head, affixed to the pump, holds an aerosol molecular-type filter paper upon which the radon daughter product particles are deposited. As the pump is previously calibrated for a standard rate of operation, the time required to draw the sample will indicate how many liters of air has passed through the filter paper. When the plunger-type pump is used, each stroke represents the intake of 1 liter of air. 2. Remove the filter paper for each sample from the mine, after placing each in a glassine envelope for protection until the radiation on the filter paper is measured. 3. Take an alpha survey meter reading of the filter activity from 40 to 90 minutes after end of sampling. Convert the alpha survey meter reading to disintegrations per minute (dpm). 4. Divide this reading by the number of liters sampled to give dpm per liter. 5. Divide the dpm per liter by the factor on the graph shown in figure 1. 6. The resulting figure gives the multiple or fraction of the suggested working level (1.3 x 105 Mev/1) existing in the air. Multiply this figure by 1.3 x 105 to determine the amount of potential alpha energy in million electron volts of energy per liter of air. Details of the sampling method are described in a recent article.10/ Advice regarding the purchase of equipment may be obtained from the Field Station, Occupational Health Program, United States Public Health Service, Box 2537, Fort Douglas, Salt Lake City, Utah. 10/ Kusnetz, H. L., Radon Daughters in Mine Atmospheres A Field Method of Determining Concentrations: Am. Ind. Hyg. Assoc. Quart., vol. 17, March 1956, pp. 85-88. At present the Federal Bureau of Mines has clear responsibility under Order 1940, issued by the Secretary of the Interior, for all mine safety inspections in mining operations on the Public Domain, Indian lands, and other Government-leased lands. In an opinion dated May 18, 1956, however, the associate solicitor of the Department of Interior concluded that the Federal Bureau of Mines has no authority to make safety inspections of uranium mines located on the Public Domain, where the lessee obtained his lease from the Atomic Energy Commission or where, instead of a lease, the operator or owner has filed a mineral claim. The Bureau of Mines has no authority to inspect uranium mines on privately owned land. STATE REGULATORY MEASURES Mining laws are formulated by the Governments of the States to protect both employees and mine operators. In the interest of mine safety, it is strongly recommended that everyone concerned with mining should familiarize themselves with the State laws and comply with them. Excerpts from regulations of the three major uranium producing States New Mexico, Utah, and Colorado are quoted as follows: RADIATION PROTECTION (b) New Mexico Mine Safety Code for All Mines Including In any underground uranium mine producing radioactive ores in which radon gas is present, the operator shall provide on the surface or underground, a fan or other mechanical device for producing and controlling air circulation within the mine capable of delivering fresh air at the rate of five hundred cubic feet per minute for each man or at a higher rate where it is necessary to reduce to acceptable levels the danger from radon gas encountered where men are working. For this purpose the Mine Inspector may, in his discretion, prescribe the rate or rates for the delivery of fresh air by mechanical means for any such mine or any particular workings therein. Passed by the Industrial Commission of Utah, Salt Lake City, Utah, IT IS ORDERED: 1. 2. 3. That the General Safety Orders issued by The Industrial The operator of every uranium mine, whether operated by shaft, slope, The atmospheric concentration of the immediate daughters of radon Rule on Determination of Concentration of the Immediate Daughters It shall be the duty of every operator to cause an inspection of Recording of Determinations It shall be the duty of the operator to maintain a record book at 755 In places containing radon gas and its decay products the maximum allowable concentration for the alpha emitting decay products of radon should not exceed one hundred (100) micro-microcuries per liter of air. 4. The maximum allowable concentration of toxic dusts, mineral dusts, and fumes shall be according to the standards in Regulation Three (3) on Occupational Hazards, as set forth by the Colorado State Department of Public Health. 5. When employees are exposed for only short periods of time to dust 6. Drill holes underground shall not be collared dry, but drilling water shall be turned on before the air drill is put in operation, or other means used to control dust. 7. All chutes from which dusty ore or rock is taken shall be equipped with a sprinkler or other such device which will effectively dampen such rock or ore, which will prevent the escape of dust in the atmosphere. 8. Wherever the sprinkling device is installed in a chute for the purpose of preventing the escape of dust, it shall be so placed that it can be operated by the employees loading cars at the chute. 9. Wherever it is necessary for an employee to use a respirator in the performance of his duty, such respirator must be furnished by the employer. 10. Respirators shall be of an approved type, kept clean and sanitary, and the employee must wear them where needed. 11. Before starting mucking or shoveling in any working place, the working place, and ore or rock piles, shall be sprinkled before starting work, and kept sprinkled as often as necessary so that no dust will arise from such pile of ore or rock. 12. In underground workings where dusty waste is being used for back filling, it shall be kept damp so that it cannot contaminate any air course with dust. 13. District mine inspectors will, as frequently as necessary, |