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Vermiculite deposits are associated with volcanic ultramafic rocks rich in magnesium silicate minerals, and flakes of the mineral range in color from black to shades of brown and …
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Vermiculite, in ore concentrate and exfoliated state, may contain small quantities of crystalline silica, as quartz. This is usually only present as non-respirable particles but ... Some countries will even require any material containing more than 0.1% crystalline silica to be labelled as a carcinogen. Information given in this booklet is only ...
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2020, a U.S. exfoliating plant in Florida closed, while another in New Mexico ceased producing exfoliated vermiculite. Exploration and development of vermiculite deposits containing medium, large, and premium (coarser) grades (greater than 5-millimeter particle size) are likely to continue (mostly in China and South Africa) because of the higher
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Vermiculite comprises a group of hydrated, laminar magnesium-aluminum-iron silicate minerals resembling mica. They are secondary minerals, typically altered biotite, iron-rich phlogopite or other micas or clay-like minerals that are themselves sometimes alteration products of amphibole, chlorite, olivine and pyroxene. Vermiculite deposits are associated with volcanic ultramafic …
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Vermiculite, when subjected to heat, exfoliates to form elongated concertina like particles which are lightweight, incombustible, compressible, highly absorbent, and non-reactive. Exfoliated vermiculite particles can have high cation …
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Vermiculite ore mined near Libby, Montana was contaminated with ... When working with asbestos, including asbestos-containing vermiculite, the goal at a minimum is to reduce asbestos exposure to below the OSHA 8-hour time-weighted average permissible exposure limit of 0.1 fiber/cm . To ensure this
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Flakes of raw vermiculite concentrate are micaceous in appearance and contain interlayer water in their structure. When the flakes are heated rapidly to a temperature above 870 degrees …
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Vermiculite ore--containing high concentrations of asbestos--was mined at Libby between 1923 and 1990, and accounted for most of the world's vermiculite. Mining, processing, or any disturbance of the contaminated vermiculite releases asbestos fibers into the air, which can lead to respiratory illnesses, including asbestosis.
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ATSDR issued cooperative agreements to select state public health agencies to conduct health statistics reviews related to potential human exposure to contaminated vermiculite ore (an asbestos-containing mineral) at sites across the United States.
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Vermiculite ore deposits, like most other rocks, contain an assemblage of other minerals besides the vermiculite (Addison and Davies 1990). There may be major components such as feldspars, pyroxenes, amphiboles, carbonates, and quartz, as well as minor components such as phosphates, iron oxides, titanium oxides and zircon (Atkinson et al 1982).
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Vermiculite is produced from ore mined throughout the world. In the United States, mines are located in Montana, South Carolina, and ia. When heated, the ore expands into a light, …
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BackgroundLibby, Montana, was home to the largest vermiculite ore mine in the United States. The processing, use, and transport of the ore, which was contaminated with amphibole asbestos, led to generalized contamination of the community. The mine closed in 1990.ObjectivesWe examined the prevalence of respiratory symptoms in 2000–2001 and their …
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the patent discloses that the dispersions can be prepared by treating vermiculite crystal with a solution containing a cation which can diffuse between the interlayers of the crystal's mineral structure and cause gross swelling in a direction normal to the main cleavage plane of the layer during immersion in water, immersing the treated vermiculite in water and permitting the …
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Asbestos-Contaminated Vermiculite in Libby, Montana 2001-S-7 March 31, 2001 . Report 2001-S-7 Inspector General Staff ... contaminated vermiculite ore, which has been mined near Libby since the 1920s. Subsequently, ... posed by friable asbestos-containing materials in school buildings and commercial and industrial
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W.R. Grace acquired Zonolite in 1963 and operated the vermiculite mine until Sept. 1990. The Montana Supreme Court's ruling noted that the vermiculite "contained a significant amount of amphibole asbestos" and that ore processing "released dust containing fine asbestos fibers into the air." Ore concentrate was loaded on BNSF railcars.
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Actively engaged in the mining of vermiculite ore and/or the production of vermiculite concentrate, or 3. A sales agent or broker of a person, firm, organization or corporation which qualifies as, but is not, a Mining Member ... Actively engaged in the manufacture of products containing vermiculite, or 3. A mining company that produces 10,000 ...
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contaminant of vermiculite ore that was mined in Libby, Montana. Vermiculite is a silver-gold to gray-brown mineral that has been used as building insulation or as a soil amendment. Because asbestos fibers are so small, this contamination is not evident with the naked eye. Shipments of the asbestos-containing vermiculite were sent to processing
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Vermiculite, in ore concentrate and exfoliated state, may contain small quantities of crystalline silica, as quartz. This is usually only present as non-respirable particles but mechanical action such as milling may reduce any quartz that may be present to a respirable particle size. Silica …
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This case analysis raises several concerns: risks of vermiculite induced disease among former workers of the more than 200 expansion plants throughout the United States; health effects of brief but very high-intensity exposures to asbestos; and possible health effects in end-users of consumer products containing vermiculite.
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Some previously marketed asbestos-containing products, such as amphibole-contaminated vermiculite insulation, remain in many homes and other buildings in the United States. ... Vermiculite contaminated with asbestos was produced as late as 1990 from a mine near Libby, Montana. The mined vermiculite ore contained amphibole asbestos. It was ...
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Libby, Montana, was home to the largest vermiculite ore mine in the United States. The processing, use, and transport of the ore, which was contaminated with amphibole asbestos, led to generalized ...
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It is believed that about 70% of the deposits are not pure vermiculite, but rather mixed-layer mica-vermiculite structures containing vermiculite and biotite (phlogopite) in various proportions . Such a structure can be regular or irregular, but in any case it affects the properties of vermiculite ore, in particular expansion.
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&EPA EPA910-R-01-002 United States Environmental Protection Agency Region 10,1200 Sixth Avenue, Seattle, WA 98101-1128 Feasibility for Identifying Mineralogical and Geochemical Tracers for Vermiculite Ore Deposits February, 2001 Prepared By David Frank and Lorraine Edmond U.S. Environmental Protection Agency Office of Environmental Assessment Region 10
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The U.S. Department of Health and Human Services (DHHS) is addressing public health concerns regarding a fibrous amphibole that occurs in vermiculite ore in the Libby, Montana, area. Scientists agree that exposure to this mineral increased the risk of nonmalignant respiratory and pleural disorders, lung cancer, and mesothelioma in groups of people who worked in the now …
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Do you manufacture products containing vermiculite? Yes. Do you supply equipment or materials, other than vermiculite ore and/or vermiculite concentrate, used in vermiculite industry? No. Are you engaged in the technical or scientific advancement of vermiculite and its uses? Yes.
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Dry the exfoliated product either on a hotplate or in an oven. 8.3.6 Soil Samples Containing Crude Vermiculite Ore Soil samples containing crude (unexfoliated) vermiculite ore probably also contain organic constituents which need to be removed prior to analysis. Exfoliation in a muffle furnace is the optimum approach, because in one operation ...
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Technically, vermiculite is a hydrated magnesium iron aluminium silicate mineral in the form of shiny flakes, which are usually golden brown to blackish in colour. Vermiculite is expanded …
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Vermiculite ore containing hazardous Libby asbestos was processed in Northeast Minneapolis from 1938-1989. This page contains information about the vermiculite, ways people were exposed, potential health …
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Europe PMC is an archive of life sciences journal literature.
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Lump of vermiculite ore, screened vermiculite, exfoliated vermiculite (Picture courtesy of Palabora Europe) Vermiculite is a hydrated magnesium aluminum silicate mineral which resembles mica in appearance. It is found in various parts of the world including Australia, Brazil, Bulgaria, Kenya, Russia, South Africa, Uganda, USA and Zimbabwe. ...
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Vinikoor LC, Larson TC, Bateson TF, et al. Exposure to asbestos-containing vermiculite ore and respiratory symptoms among individuals who were children while the mine was active in Libby, Montana. Environ Health Perspect. 2010;118:1033–1128. doi: 10.1289/ehp.0901680. This is the first study to examine health outcomes among Libby residents who ...
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Strategy for Further Assessment of Vermiculite Ore Asbestos Sites September 30, 2008 I. Background : The Agency is committed to developing a strategy by the end of FY08 for conducting further assessments of vermiculite ore asbestos sites: "We agree it would be prudent to take another look at the completed site assessments
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When vermiculite (Zonolite ore) is disturbed it can release billions of asbestos fibers into the air which increases the risk of lung cancer, mesothelioma, asbestosis and other asbestos related diseases. If the area containing the vermiculite is avoided and left undisturbed, then risk of exposure to asbestos fibers is decreased.
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BackgroundLibby, Montana, was home to the largest vermiculite ore mine in the United States. The processing, use, and transport of the ore, which was contaminated with amphibole asbestos, led to ge...
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vermiculite ore (an asbestos-containing mineral) at sites across the United States. These sites were identified by the U.S. Environmental Protection Agency (USEPA) as having possibly received vermiculite from a mine in Libby, Montana. Specifically, the purpose of these health
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There were veins of asbestos in the mined ore that ended up in the final product, and it is estimated that between 3 million and 30 million homes have vermiculite insulation in the attic. Peak period of production was the 1950s through the 1970s, and the estimate of homes affected varies so widely because it was primarily sold for homeowner ...
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