30 CFR 57.5047 - Gamma radiation surveys.
(a) Gamma radiation surveys shall be conducted annually in all underground mines where radioactive ores are mined.
(b) Surveys shall be in accordance with American National Standards (ANSI) Standard N13.8-1973, entitled “Radiation Protection in Uranium Mines”, section 14.1 page 12, which is hereby incorporated by reference and made a part hereof. This publication may be examined in any Metal and Nonmetal Mine Safety and Health District Office, Mine Safety and Health Administration, or may be obtained from the American National Standards Institute, Inc., 25 W. 43rd Street, 4th Floor, New York, NY 10036; http://www.ansi.org.
(c) Where average gamma radiation measurements are in excess of 2.0 milliroentgens per hour in the working place, gamma radiation dosimeters shall be provided for all persons affected, and records of cumulative individual gamma radiation exposure shall be kept.
(d) Annual individual gamma radiation exposure shall not exceed 5 rems.