From The Vermiculite Institute website:
revised June 13, 2002
RJ LeeGroup, Inc.
The Materials Characterization Specialists
June 03, 2002
Mr. David DuVal
RE: Laboratory Analysis of Uganda Vermiculite
RJ Lee Group Project Number: LSC205805 (Ref No. MAC2O5O19)
Dear Mr. DuVal:
Enclosed are the results from the scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) analyses of the Uganda vermiculite sample. The sample was received on May 24, 2002 and was assigned Ri Lee Group sample number 3030664.
The as-received samples were reduced into representative 100 gram portions through the use of a riffle splitter. Each portion was then dried at 50 °C until no further weight loss was observed. The dried sample was then separated into greater than 500 micrometer and less than 500 micrometer fractions using wet (methanol) sieving techniques. Each portion was then dried and the mass of each fraction obtained.
Both size fractions were analyzed by polarized light microscopy (PLM) using the analytical method as outlined in EPA/600/R-93/l16. The PLM report was sent to you on May 30, 2002. The less than 500 micrometer fraction was also prepared and analyzed using SEM/EDS techniques.
Sample preparation for the SEM/EDS analyses involved suspending a known (approximately 200 mg) of less than 500 micrometer diameter material in 100 ml of methanol and sonicated for two minutes. A 0.5 ml aliquot was removed from the center of the suspension and then redeposited onto a 0.4 micrometer pore size 25 mm filter using vacuum filtration techniques. The entire filter was then mounted to an SEM stub using colloidal graphite. A thin layer of carbon was then applied to each prepared specimen using evaporative deposition under vacuum to minimize charging while in the SEM.
The identifications of fibrous structures during the SEM/EDS analyses were based on fiber morphology and elemental chemical analysis (i.e. EDS). Each fibrous particle was then measured during the analyses. Morphological characteristics such as parallel sides, presence or absence of cleavage sides / ends, parallel fibers occurring in bundles, bundles having splayed ends or fibers displaying curvature were used to determine fiber classifications. The sample was analyzed at magnifications up to 5000X for structures that were >5 micrometers in length and having a length to width ratio greater than >5:1.
The weight percentages were estimated by summing the individual calculated masses of the structures detected in the area analyzed and then extrapolated to the total weighed subsample. The mass of the individual structures were calculated using the structure dimensions and a density of 2.66 g/cc for chrysotile and 3.25 g/cc. for amphiboles.
The following table summarizes the SEM data for the < 500 micrometer fraction:
No regulated asbestos minerals were observed during this analysis.
RJ Lee Group is accredited by the National Voluntary Laboratory Accreditation Program (NVLAP #101208-00) for asbestos fiber analysis. This report may not be used to claim product endorsement by NVLAP or any agency of the US government.
These results are submitted pursuant to RJ Lee Group's current terms and conditions of sale, including the company's standard warranty and limitation of liability provisions. No responsibility or liability is assumed for the manner in which the results are used or interpreted. Unless notified in writing to return the samples covered by this report, RJ Lee Group will store the samples for a period of ninety (90) days before discarding. A shipping and handling fee will be assessed for the return of any samples.
If you have any questions or comments regarding the information contained herein, please feel free to contact me.
Sincerely,
Drew R.Van Orden, P.E.
Senior Scientist
The RJ Lee Group also tested this new deposit and mine of vermiculite using the less critcal PLM (polarized light microscopy) test method. In a letter dated May 30, 2002, they reported that "no asbestos was detected in the sample covered by this report." Copies of this report are availabe from Mr DuVal representing the Ugandan vermiculite in the United States.
The Vermiculite Institute Back to
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Client Identification
Ri Lee Group ID
Asbestos Content
Sensitivity, %
Uganda Vermiculite
3030664
None Detected
<0.002
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