Document X7LXdLnYJL829zeDw8bZgeGZx
CAMBRIDGE
TO: h. C. Duecker
FROM:
J. C. fang
CC: K. A. Brown T. ?. Felt A. M. 3osenberg B. R. Williaas J. L. Wright
OATE: June 26, 1973
SUBJECT:
The possible occuranee of asbestos in Monokote
E:cyanded Vcrmiculite samples and Monokote products frca various mining locations and plants have been analyzed since Dec.. 1972, by quantitative X-ray diffraction method (developed by Arthuz D. Little, Inc.). This is supplemented by up sic el micrsecojy (dispersioa staining techniques de/eloped by Arthur D. Little, Inc.), transmission electron microscopy (rub-cut method, developed by Johns-Manville, but used ourselves at WRC) and scanning electron microscopy vith X-ray fluorescence analysis attachments (Arthur D. Little, Inc.).
Based on the experimental results collected up to date, tentative con clusions and comments are summarized as follovs:
1. Vermicuiite contains a small amount of asbestos in the range of Q.%. The only asbestos species detected is tremolite; it can be either in platy or fibrous mor phology. The analyses ere presented in Table 1.
2. Sampling technique for the analysis is extremely important all the analytical techniques mentioned above require very small specimens. Because of the heterogeneous nature of mineral species present, difference in density and forms, segregation, tends to occur. Representative analysis of a trace mineral in tills material can be achieved only by collecting a large number of samples, perhaps 10 or more randomly and average the findings. Repetitious sampling (in Tables 1 and 2) show the variations in the determinations.
7 Monokot : product contains approximately a maximum of 39Tj
-1 .0 * i vermicuiite, 56-60^2 gypsum and a minor amount (-'.)
of ilc materials. The only asbestos containing ir.mred-
vermiculite. Since she tremolite content of the
ex
: ? + <
.bout Q.%, Monokote prod
ha- :-ss than 0.tr lite by computation. Lu aiory
m Table 2 confirms the computed results.
To. Identification I?o. 1 22203-2
2 22209-9 3 222C9-10 1 22209-'ll 5 22209-12
Dascriptiion of Sanpies Location o: Ore Locations of Inpandins
Trenoiitn Content Anal:,'sed Zy: ADii XI
South Carolina
Trenton
0.30
-
East Hampton
0.30
0
Montana
Denver
0.c5
-
South Carolina
Little P.ock
^o.a.o. 45 -
South Carolina
Znoree
<0.2
0
Average;: .ADD j!-:
Total
0.43 0.33
Table 2 - Analysis of Honchote Pro facts
VJI
,.o. Identification !!o. t - 22203-9 12 22203-10 13 22203-11 14 22203-12
22209-1 2220>2 9O
Jescriotion of Sarnies location of Ore Looaticn of Tana.
Denver
Montana
Los Angeles
Montana
Oregon
"'a*'*
,*a - - *
ATT 0 0 0 0
0.3
<0.2
0.7.<0.2
.r.-croge - .ot:
2
V.
k. Vie fcre continuously inproving the techniques for these analyses such as to determine the ratio of platy fora vs. fibrous fora of trenolite, to distinguish the fibrous trenoiite vs. other fibrous-lihe minerals such as horn blende and contaminants which may lead to sore accurate resolutions and identifications. In addition, ve are trying to ceteraine the number of samples required to give a statistically reliable analysis.
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