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uc INTERNAL. CORRESPONDENCE UNION CABS3DE CORPORATION ?70 PARK AVENUE, NEW YORK. NEW YORK 10017 To (Nom) Diyiiia/i l acts Non Copy to Mr. J. A. Riddle Mining & Metals.Division P. 0. Box K King City, California Mr. J. F. Crow Mr. E. A. Piersall Mr. R. 0, Marsden Dr. J. J. Welsh/Dr. K. S. Lane g.r. August 21, 1970 Originating B.pL AntWtiflfi sbM DISTRIBUTION J. A. Riddle R. O. Marsten R. O. Houpsr L. F. Crc.v R.J . Krcnnyfe B. E. Us'?y R. Crce an J.M. Andersen A A. ArJ.rado K. A. V` -t-1 G, L Ver.eu X. West R. Rivera n D. Sewell D. Garcia Dear Mr. Riddle: The results for particle counts of air samples collected at the asbestos mine near King City are given below. They are reported as fibers of length equal to or greater than 5 microns and as total particles of all sizes visible by microscope at a magnification of 400 times. For safety, all particles having a dimension greater than 5 microns have been reported as fiber. It is understood of course, that some of these particles may not be fiber at all; on the other hand we know from earlier studies that fibers when agglomerated may appear to be a single large particle that cannot be better delineated except by much greater magnification. Particles per ml. A I 02 1 3 Sampling Location = 5/ Total Remarks Beside bulldozer operator while moving ore to loader. 13 65 Open cab. Sunny 11 80 dry day. Light breeze. Beside front loader operater while moving ore to grizzly. Floor of pit around grizzly. 41 53 7 123 Closed, air conditioned 130 cab. Dust leaks. 60 UCC 000064 Mr. J. A. Riddle -2- August 21, 1970 You will note that in all instances the 5 micron and larger material exceeds the limit of 5 per ml. Except for the two lowest readings, the total particle count can, by further computation, be shown to exceed the alternative limit of 2 million particles per cubic foot of air. Thus, for safety, personnel working at the mine should wear respirators. It is strongly indicated for the operator of the front loader. I also suggest that consideration be given to a means for providing a cover for the ore during haulage. I feel that in the near future this will be required by the state. Very truly yours, PWM: dp a*-.' L- * / ' ' Paul W. McDaniel Industrial Hygiene Engineer UCC 000065 A 1 02 !