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Research about Libby, Montana

Source-linked reports with geographic coverage including Libby, Montana.

6 recordsLinked to original sources
USGS2012

Preparation and characterization of "Libby Amphibole" toxicological testing material

The U.S. Environmental Protection Agency (USEPA) began work in Libby, Mont. in 1999 when an Emergency Response Team was sent to investigate local concern and media reports regarding asbestos-contaminated vermiculite. Since that time, the site has been granted Superfund status and site remediation to a safe level of asbestos has been ongoing. The amphibole asbestos from the Vermiculite Mountain vermiculite deposit near Libby, Mont. (Libby amphibole) is unusual in the sense that it is currently not classified as one of the regulated six asbestos minerals—chrysotile (a serpentine mineral) and the amphibole minerals amosite (asbestiform cummingtonite-grunerite), crocidolite (asbestiform riebeckite), asbestiform anthophyllite, asbestiform tremolite, and asbestiform actinolite. The amphiboles from the Vermiculite Mountain vermiculite deposit, primarily winchite and richterite, are related to tremolite and in the past have been referred to as sodium-rich tremolite or soda tremolite (Larsen, 1942; Boettcher, 1966; Wylie and Verkouteren, 2000; Gunter and others, 2003; Meeker and others, 2003). The public health issues in Libby, Mont. have brought to light many of the inconsistencies in the literature regarding fiber characteristics, nomenclature, and toxicology. To better understand the toxicological characteristics of the Libby amphibole, investigators require a sufficient quantity of material representing the range of fibrous amphiboles present in the vicinity of Vermiculite Mountain to use in toxicology studies. The material collected in 2000 (Meeker and others, 2003) has been exhausted and a second collection and preparation effort, funded by the USEPA, was conducted in 2007. Both the 2000 (LA2000) and 2007 (LA2007) materials were generated to support research needs identified by the USEPA and the National Toxicology Program, and new in-vivo and in-vitro toxicology studies are underway. This Open-File Report describes the process of preparation and summarizes the chemistry and mineralogy of the LA2007 toxicological testing material.

Libby, Montana↗
USGS2010

The dispersion of fibrous amphiboles by glacial processes in the area surrounding Libby, Montana, USA

Mining operations began at a world-class vermiculite deposit at Vermiculite Mountain near Libby, Montana, circa 1920 and ended in 1990. Fibrous and asbestiform amphiboles intergrown with vermiculite ore are suspected to be a causative factor in an abnormally high number of cases of respiratory diseases in former mine and mill workers, and in residents of Libby. The question addressed in this report is whether some of the amphibole from Vermiculite Mountain could have been dispersed by Pleistocene glacial processes rather than by human activity after vermiculite mining began. The history of Pinedale glaciation in the Libby area provides a framework for estimating the presence and distribution of asbestiform amphiboles derived from Vermiculite Mountain and found in naturally occurring sediments of Glacial Lake Kootenai that underlie the Libby Valley area. There were two situations where sediments derived from Vermiculite Mountain were deposited into Glacial Lake Kootenai: (1) as lake-bottom sediments derived from meltwater flowing down Rainy Creek when the valley south of Vermiculite Mountain was free of ice but active ice still covered Vermiculite Mountain; and (2) as lake-bottom sediments eroded from the Rainy Creek outwash and re-deposited during a re-advance of the Purcell Trench Glacier lobe near Moyie Springs, Idaho.

Montana↗
USGS2002

Reconnaissance study of the geology of U.S. vermiculite deposits: Are asbestos minerals common constituents?

Unusually high incidences of asbestos-related mortality and respiratory disease in the small town of Libby, Montana, have been linked to amphibole mineral fibers intergrown with the vermiculite deposits mined and milled near the town from 1923 to 1990. A study conducted by the U.S. Agency for Toxic Substances and Disease Registry concluded that mortality due to asbestosis in Libby mine and mill workers and residents during 1979 to 1998 was much higher than expected for a similar Montana or United States population group. Recent medical testing of past and present mineworkers and residents of Libby showed lung abnormalities in nearly one-fifth of the adult study participants. The U.S. Environmental Protection Agency, under Superfund authority, is completing sampling and cleanup of asbestos-bearing materials in the mine, mill, and town sites. The U.S. Geological Survey is conducting a study, reviewed herein, to investigate the mineral content of other U.S. vermiculite deposits and to determine if the amphibole asbestos minerals like those found in the Libby deposits are common in other vermiculite deposits.

Montana↗
USGS1934

Gold-quartz veins south of Libby, Montana

The area described in this paper is one of rugged mountains, composed chiefly of folded and faulted sedimentary rocks of the Belt series. In the nearby region the beds are intruded by diorite sills and granitic stocks. Glacial drift, including silt deposited in a lake, covers much of the lower slopes of the mountains and partly fills the valleys. Incomplete records show a production of $200,000 in gold, mostly from the oxidized free-milling parts of quartz veins. Except a few in the Wallace formation the veins are found in sandstone and shale of the Prichard formation. They partly replace the country rock along fractures that commonly follow bedding planes but also cut across them at moderate angles. The veins average between 1 and 2 feet in thickness and reach a maximum of 6 feet. They are cut by faults of small displacement, with which the ore bodies are commonly associated. Quartz forms 95 percent or more of the veins. Of the remainder, one or more of the minerals pyrite, galena, sphalerite, and pyrrhotite are relatively abundant, and chalcopyrite, arsenopyrite, tetrahedrite, and scheelite are present sparingly. A little silver is present, and in some veins it exceeds the gold considerably. In many veins an original quartz filling has been slightly brecciated or sheared by movement parallel to the walls. Sulphides and gold have been introduced along the shear planes, partly replacing the quartz and giving the vein a "ribbon" structure. The gold is closely associated with the sphalerite, and silver is more plentiful in the veins that carry galena. As a rule oxidation has not extended far below the surface, and its chief product is limonite. Cerusite and anglesite are present in some veins, and a little malachite, azurite, pyromorphite, or manganese oxide occurs in a few. Native gold is present in both the oxidized and unoxidized ores. Although mining of these veins in the past may have been unprofitable, that result was due partly, at least, to difficulties of transportation and milling. With improvement in roads and methods, not to mention appreciation in the value of gold, the deposits are believed to have a promising future.

Montana↗