Document 37bGN6JGZMo2QM4OwMz4gv7dy

United Stales Department of the Interior BUREAU OF MINES <900 L A S A L L i ROAD AVONDALE, MARYLAND 20781 A pril 26, 1984 - -'VM * __ . . . ; ' i w A ' '!>*.'y 'l :"+?i Mr. George J. Dippold, Vice President Whittaker, Clark & Daniels, Inc. 1000 Coolidge Street South Plainfield, New Jersey 07080 1000 Dear Mr. Dippold: The 18 talc samples received in March 1 9 M have been examined using polarised light microscopy (PLM), X-ray diffraction (XRD), and transmission electron ' >. microscopy (TEH). The samples were examined for the presence of asbestiform mineral particulates. . >K\ Tne mineral serpentine i6 present in minor amounts in samples 720TGRRx, 720TGRPd, 720TTPRX, 720TTPPd,_ 720TTERx, and 720TTPd. Only the platy variety =' of serpentine was observed; no chrysotile, the asbestos variety of serpentine, was observed by PLM or TEMr Approximately 1/2 to ] weight percent tremolite is present in samples 720TTPPd, 720TTPRx, and 720 TTEPd. Trace amounts (<l/2 weight percent) were observed in samples 720TGR|ki, 720T02Pd, 720TDMPd, 720T13Pd, and 720TDMRx. Ail tremolite particles observed using PLM were blocky with maximum aspect ratios of approximately 8 to 1. Some short, thin tremolite particles with widths below the resolution of the light microscope, were observed using TEM. The maximisr aspect ratio observed by TEM was 20 to 1 with most of "the elongated tremolite particles being 10 to 1 or less in aspect ratio. Some of Che ' tremolite observed in these samples would meet the current regulatory dimensional definition of asbestos (>5 pc in length and >3 to 1 aspect ratio), Fourteen of the eighteen samples contained fibrous talc in trace to minor amounts. Aspect ratios of the fibrous talc particles were generally less than 1C to 1 with s fev particles- approaching an aspect ratio of 20:1. Many of these particles exceed 5 pm in length and meet the morphological criteria of a regulatory fiber, however, they would not be classified as asbestos. lj4 CLAStv 4 J. IM. PLAINTIFFS EXHIBIT WCD-185 WCD 001685 These analyses represent only the samples submitted for examination. If yovj have any questions concerning the analyses, please contact Robert Virta at . >ri (301)436-7541, or call me at (301)436-7501. Sincerely, > . Enclosures: Figures 1 and 2 cc: Robert A. Clifton, Jr. William J. Campbell . Research Director ; y.ti\ : -,f bcw %?. Is $ - *] H9 ' M il -- L< -v; - (Vi <<;< j : M * > -*. M ; *.'-r*'*kC *.ftir.r*) rV S .-V * ,- jv WCD 001686 FIGURE 1. - Electron micrograph showing platy talc particles observed in sample 720TEEPd <sr-r:. c <: -S. U.C- l' FIGURE 2 - Konrepresentative field of view of sample 720TGRRx showing talc ranging from platy to fibrous in morphology WCD 001687