Association Committee on Radiation Protection as recorded in table II, this data indicates that approximately half of all the working areas sampled required corrective measures to make them safe. Furthermore, 64 samples (26 percent) of the 224 total were 10 times the safe working level or over. Again, on the basis of the recommendations in table II, mining activities should have been suspended in about one-fourth of all the areas sampled until corrective measures reduced the radiation hazard to a safe level. RECOMMENDATIONS 1. Each mine should have available means for determining radiation levels (radon daughter and gamma radiation). The American Standards Committee recommends that air samples be taken in all working areas at 3-month intervals, and whenever new areas are opened or ventilation conditions are changed. 2. Whenever samples collected indicate excessive radiation hazard, as indicated by table II, the appropriate corrective measures should be begun imme diately. In most cases the application of sound engineering principles, i.e., ventilation, bratticing, etc., would be sufficient for adequate control. The survey indicates that in most mines, a ventilation plan which would control siliceous dust would also satisfactorily control the miner's exposures to radioactive dust and gas. 3. In special cases, where unusual problems exist, competent engineering advice should be obtained from private firms, the State or U.S. Public Health Service in seeking a solution. 4. Periodic surveys should be conducted by the State to (a) evaluate corrective measures taken by mine operators, (b) check the procedure and instruments used by the mines for sampling and advise operators as to suitable control procedures. In the table are the action points indicated for a given radon daughter concentration (expressed as multiples of the safe working level) found in a single grab sample collected in a mine working area. ACTION TO BE TAKEN Safe for 8 hour workday indefinitely. Should be resampled to determine if actual weighted average (Report on AEC control program for uranium mill operations follows:) Hon. CLINTON P. ANDERSON, ATOMIC ENERGY COMMISSION, Washington, D.C., February 12, 1960. Chairman, Joint Committee on Atomic Energy, DEAR SENATOR ANDERSON: As you may recall, early AEC exploration on withdrawn lands resulted in the discovery of a number of uranium ore deposits. Many of these deposits were leased to private operators in support of the uranium production program. Although no new leases have been issued for several years, leases are still in effect covering 17 active underground mining operations. Last spring arrangements were made with the U.S. Bureau of Mines to make quarterly inspections of each of the mines operated under AEC lease. The purpose of these inspections, which were begun in July 1959, was to determine the need to improve safety practices and to measure concentrations in the air of radioactive decay products of radon (daughters) and levels of radiation from the ore. The first reports were received in October 1959. Such reports of inspections are furnished to the operators, to the State authorities, to the U.S. Public Health Service, to the Department of Labor, and to the AEC. In these reports, radon daughter concentrations are expressed as multiples of a working level. According to the testimony of Duncan A. Holaday of the U.S. Public Health Service before the Joint Committee on Atomic Energy at hearings on employee radiation hazards and workmen's compensation in March 1959, a working level was adopted at an interagency meeting in 1954 for use in uranium mines as a number to which it would be desirable to see concentra. tions reduced. The value of the working level is 300 micromicrocuries per liter of air of alpha emitting daughters of radon. The working level is considered to be the average concentration to which a man can be continuously exposed 40 hours a week throughout his working life without suffering discernible respiratory damage. The following is a summary of the results as they pertain to radiation levels: 1. Inspection reports covering the 17 active underground mining operations have been received. A total of 57 air samples were taken in various mine working areas for the measurement of the concentration of alpha emitting daughters of radon. From two to seven samples were taken in each mine. 2. Based on the data collected, the average of samples from 3 mines had radon daughter concentrations below the working level; 1 had an average concentration of between 1 and 3 times; 7 had 3 to 10 times; and 6 exceeded 10 times the working level. 3. In none of the mines was the external radiation found to be above the permissible exposure level as set forth in appendix C of title 10, CFR, part 20. 4. The Bureau of Mines notes that the data reported show conditions only at the time and place sampled. Concentrations of radon daughters at any given location are known to vary widely with a number of operating conditions. Also, the readings do not assess the individual miners' exposure. It will be seen from the foregoing that in most of the mines the radon daughter concentrations exceed the working level. Adequate ventilation should in nearly all cases correct this situation. As a result of the Bureau's inspections and conferences between the mine operators and the staff of AEC's Grand Junction office, most of the lessees are installing ventilating equipment or have it on order. In addition, in some instances, old workings of the mines are being closed off and the necessity for new air entries are being studied or engineered. Our Grand Junction staff is following this work closely. Also, reinspections of those mines which have had sufficient opportunity to take corrective action are now being scheduled by the Bureau. Every effort is being made to expedite the work of the Bureau of Mines and to obtain conclusive data. The aggregate production of the leased mines is on the order of 8,000 tons a month, or about 1.3 percent of the total domestic uranium mine production. At the time of the inspections 8 of the mines employed a total of 5 men or less each, 8 from 6 to 20 men each, and 1 mine employed 34 miners underground. AEC leases, most of them short term, contain provisions requiring the lessee to perform all mining operations in a manner consistent with good safety standards and to provide adequate mine ventilation. The AEC will take such steps as may be necessary, including termination of leases, to insure that all of its leased mines are operated in a manner consistent with established safety standards. As noted above, the State authorities, which have regulatory authority over safety conditions in mines, including radiation hazards in uranium mines, are being kept fully informed of the findings of the Bureau of Mines and of the AEC activities in this area. We will keep you advised of further developments. Sincerely yours, A. R. LUEDECKE, General Manager, APRIL 4, 1960. Gen. A. R. LUEDECKE, General Manager, U.S. Atomic Energy Commission, DEAR GENERAL LUEDECKE: Confirming telephone conversation of this date between Mr. William Finan, Assistant General Manager for Licensing and Regulation, and David R. Toll, Joint Committee staff counsel, it is requested that the AEC prepare a report for the Joint Committee on safety conditions in uranium mills and AEC actions in enforcing regulations for protection against radiation hazards. It is suggested that the report include a summary of inspections made, the radiation conditions found, and the enforcement action contemplated, if any, by AEC with respect to each mill. It is requested that 30 copies of the report be submitted to the Joint Committee by May 1, 1960. Sincerely yours, JAMES T. RAMEY, Executive Director. U.S. ATOMIC ENERGY COMMISSION, Mr. JAMES T. RAMEY, Executive Director, Joint Committee on Atomic Energy, Congress of the United States. DEAR MR. RAMEY: In reply to your letter dated April 4, 1960, there are attached 50 copies of a report on the uranium ore processing mills licensed under AEC, 10 CFR 40. We have included a brief report of the radiation problems associated with the operation of uranium mills, a discussion of the enforcement program, a résumé of the inspection program for the uranium mills, and a list of the mills, together with a summary of inspections made and enforcement actions taken, and a statement of radiation conditions in each mill. Sincerely yours, R. E. HOLLINGSWORTH, ATOMIC ENERGY COMMISSION AEC RADIATION Control PROGRAM FOR URANIUM MILL OPERATIONS MAY 11, 1960 Radiation problems associated with the operation of uranium mills may be divided into two categories: potential radiation exposure to employees within the mill and the release of radioactivity to the environment. Mill employees may be exposed to airborne dust-bearing uranium because of rock-crushing operations in the milling process. Also, the final product of the mill is a powdery substance that is easily airborne. The amount of airborne dust varies greatly from one location to another throughout the mill. The crushing, sample preparation, and final product packaging areas generally have the highest concentrations. In some mills, airborne uranium dust concentrations are such at certain locations that if a person were continuously present in these areas for all of his 40-hour workweek, he would be exposed to concentrations of uranium in excess of those permitted by AEC regulations. There is some external radiation from uranium ore. However, studies conducted by the mills and a personnel monitoring program conducted by the AEC have not indicated that there are situations where employees are exposed to external radiation in excess of the permissible limits. In addition to occupational radiation problems, there are environmental problems arising from mill operations. Radioactive materials are released in the form of liquid wastes to holding ponds, drywashes, and streams, and uraniumbearing dusts escape into the atmosphere. Uranium ore contains radioactive materials such as radium and thorium in addition to uranium. These materials are waste products and are frequently discharged from the mills in the form of liquid effluents. The effluents from some mills contain concentrations of radioactive material in excess of limits allowed by AEC regulations which require that concentrations be at drinking water levels just prior to the point where they are discharged into streams. The regulations provide that upon request to the Commission, the considerable dilution factors provided by stream waters may be taken into consideration when determining whether the regulations are being met. The dusts released to the atmosphere are primarily derived from mill processes involving the handling, grinding, and roasting of ores. For the most part, these are the same processes which create dust problems within the mill. Studies thus far do not indicate that dust released to the environment is a significant problem. The permissible concentrations of uranium in air are based on the premise that a certain amount of the dust in the air reaches the lower lung where it causes the greatest radiation exposure. Experts on dust problems in milling operations have been consulted and they have suggested that a large portion of the dust created in uranium mills may be composed of particles which are too large to be inhaled and reach the lower lung. In an effort to determine the characteristics of the dust, the Los Alamos Scientific Laboratory has sampled the dust in a uranium mill where concentrations are particularly high. Preliminary results indicate that a portion of the dust may not reach the lower lung and the particle size of the dust is significant in defining the potential radiation hazard in the mill. The AEC's Winchester Laboratory has been experimenting with chemical treatment processes designed to reduce the concentration of radioactive material released as liquid effluent. Results of its studies have been promising and some mills have adopted processes devloped by Winchester. Inspections of the uranium mills have been conducted since the Commission's regulation 10 CFR, "Part 20: Standards for Protection Against Radiation," became effective in 1957. It is the policy of the AEC to inspect all uranium mills which have been in operation over 6 months. To date, a total of 46 initial, interim, and followup inspections have been conducted throughout the industry. In conjunction with the inspection program, a personnel monitoring program has been conducted in 25 mills to determine exposure of employees to external radiation. A program for spot sampling liquid effluents and concentrations of airborne radioactivity was conducted in 24 mills in 1959. Results of these programs were made available to the mills. In addition visits to 13 mills were made in December 1959 to review their survey programs. Two meetings have been held with mill management to explain the requirements of 10 CFR 20 as it relates to uranium milling. Two other meetings were held to discuss techniques and procedures associated with radiation survey programs and to provide training in radiochemical analysis techniques. The AEC follows its "Rules of Practice," contained in 10 CFR, part 2, in enforcing its regulations. The mills are notified, in writing, of areas where they were not in compliance with AEC regulations. The mills are required to inform: the AEC as to the corrective action taken. The AEC has issued 23 such notices of violation to date. If followup inspections of mills reveal that appropriate action has not been taken to correct deficiencies which were previously brought to their attention, the AEC then, as provided in its "Rules of Practice," issues orders to the mills, requiring them to correct their deficiencies and specify in detail how and by when these corrections will be accomplished. Eleven such orders have been issued. Each AEC order included an opportunity for a hearing. One mill has requested a hearing, which is scheduled to be held on May 17, 1960, in Denver, Colo. As a result of these regulatory actions, the mills appear to have made progress over the past 2 years toward resolving their radiation problems and achieving full compliance with AEC regulations. Many currently have programs for controlling exposure to airborne dust within the mill, such as limiting the time an |