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Lessons Learned from the Legend of Asbestos
Published in Ilise L. Feitshans, Global Health Impacts of Nanotechnology Law, 2018
This lesson learned can be applied to nanotechnologies, too. According to the ILO convention, “The term asbestos means the fibrous form of mineral silicates belonging to rock-forming minerals of the serpentine group, i.e. chrysotile (white asbestos), and of the amphibole group, i.e. actinolite, amosite (brown asbestos, cummingtonite-grunerite), anthophyllite, crocidolite (blue asbestos), tremolite, or any mixture containing one or more of these” [4]. The key feature of a flexible framework is that although many important details of the program are not expressly stated, the key elements of a good program are included within its purview. In so doing, the regulatory structure that was created in partnership between corporate decision makers and government saved the life of the industry. Transitioning away from the Wild West approach of voluntary disclosure not required by regulation that moved to demonstrating full compliance with new laws was not easy. ILO C162 Article 3 allows great leeway to regulators to create doable programs: “National laws or regulations shall prescribe the measures to be taken for the prevention and control of, and protection of workers against, health hazards due to occupational exposure to asbestos. . . . National laws and regulations drawn up in pursuance of paragraph 1 of this Article shall be periodically reviewed in the light of technical progress and advances in scientific knowledge” [4]. This provision anticipates the cyclical review of laws and their implementation, consistent with precautionary principles of risk management that can apply equally to bulk materials and substances applying nanotechnologies.
Whole-rock compositions of Precambrian iron formations and Phanerozoic ooidal ironstones: Comparative considerations and mineralogical differentiation of subtypes
Published in Adam Piestrzyński, Mineral Deposits at the Beginning of the 21st Century, 2001
Like the ironstones, the plots of the iron formations (solid symbols) summarized in Fig. 3 can also be classified according to mineralogical aspects. Field I represents the magnetite-free silicate fades iron-formation of Nigeria being composed of manganese-bearing grunerite-cummingtonite, spessartine-almandine and ± quartz. One plot belongs to the gold-bearing Wanderer iron-formation (carbonate fades) of Zimbabwe containing siderite, skelletal magnetite porphyroblasts, quartz and muscovite. This field is separated from a bigger and elongated field parallel to the SiO2-Fe2O3-line. The latter represents 4 subtypes which all contain quartz in strongly varying proportions: IIa contains magnetite and Fe-silicates (magnetite-silicate facies) comprising the Nigerian iron-formations consisting of magnetite, grunerite and spessartine-almandine, the Monarch iron-formation/ Zimbabwe containing magnetite, manganese-bearing grunerite and chlorite and the iron-formation of Gongchangling, Liaolin/China being composed of ferro-actinolite and magnetite, whereas lib is composed of magnetite (magnetite subfacies) and minor silicates. III contains martitized magnetite and newly-formed hematite and comprises banded iron-formations of the Fortescue Group, Pilbara Craton (Australia); Karna-tak, Chikuayakanhalli greenstone belt and Datari, Shingbum, Orissa (India); and Simandu (Guinea) and IV newly-formed hematite which may contain some martite relics (hematite-subfacies). Analogously to the groups II and III, group IV shows that the amount of SiO2 changes drastically from quartz-dominated iron formations [= banded iron-formations: Muro and Obajana (Nigeria); Simandu, Gueridou/ Chaime de Goiny; and Mt. Nimba/Mount Sempere (Liberia); Datari and Gandhamardan/Orissa and Karnatak (India); Neganayi/Keweenaw Peninsula /Michigan and Rapitan/Mackenzie Mountains (USA); and unmineralized ores of Brunos band from Mt. Tom Price and Mt. Sylvia, Dales Gorge member (DB 4 and DB 12) and Joffre Member (J3), Mt. Tom Price, Hamersley (Australia)] to iron formations being composed of nearly only hematite [= massive ore): Section 6 (West Pit), DB 2, and DB 15, Dales Gorge member, Mt. Tom Price, Hamersley (Australia); Daitari and Gandhamardan/Shingbum and Karnatak (India); Krivoi Rog (Ukraine); Faleme (Senegal); Mt. Nimba (Liberia); Itabira, Mutuca, Aguas Claras (Brazil); and El Pao (Venezuela)].
Flotation of Iron Ores: A Review
Published in Mineral Processing and Extractive Metallurgy Review, 2021
Xiaolong Zhang, Xiaotian Gu, Yuexin Han, N. Parra-Álvarez, V. Claremboux, S. K. Kawatra
A characteristic example of direct flotation in alkaline media can be found in the Republic Mine. Republic Mine’s ore is a specular hematite with small amounts of magnetite and martite. The gangue is a recrystallized chert containing sericite, grunerite, cummingtonite, and chlorite. Figure 1 outlines the refining process at Republic Mine. Key highlights of this flowsheet are: Two stages of desliming involving two cyclones, the underflow of which is treated with tall oil in a series of conditioners.Regrinding to liberate residual quartz and silicates from the iron minerals.Steam injection into the pulp conditioner, which is used to progressively raise the temperature to boiling.
Characterization of pulmonary responses in mice to asbestos/asbestiform fibers using gene expression profiles
Published in Journal of Toxicology and Environmental Health, Part A, 2018
Naveena Yanamala, Elena R. Kisin, Dmitriy W. Gutkin, Michael R. Shurin, Martin Harper, Anna A. Shvedova
Asbestos is a term for a set of commercially important naturally occurring fibrous silicate minerals. Crocidolite (asbestiform riebeckite), amosite (asbestiform cummingtonite-grunerite), actinolite-tremolite asbestos, and anthophyllite asbestos belong to the amphibole minerals, while chrysotile is a serpentine mineral (Wylie and Candela 2015). The term “asbestiform” corresponds to a mineralogical habit or form of a mineral in which single fibers (fibrils) occur in bundles that can be detached into finer fibers and display curvature (Lowers and Meeker 2002). Similar to main asbestos types described above, there are “other regulated asbestiform minerals” fibers such as durable asbestiform zeolite minerals (e.g., erionite). The term asbestos has been used in commerce and regulations, but is not recognized in geology as referring to species separate from non-asbestos analogs of these minerals (Lowers and Meeker 2002). These materials were widely used for textiles and in construction, as well as in industrial application, until the 1970’s in the USA (Williams, Phelka, and Paustenbach 2007). Although the use has declined, asbestos continues to be utilized for certain applications in the USA and elsewhere (Dodson 2016; LaDou et al. 2010). Known human diseases associated with exposure to asbestos/asbestiform fibers include asbestosis, bronchial adenocarcinoma, squamous cell carcinoma of the respiratory epithelium and large/small cell lung carcinoma and diffuse malignant mesothelioma (Andujar et al. 2016; Lemen 2016; Ndlovu et al. 2017).
Anthophyllite asbestos from Staten Island, New York: Longitudinal fiber splitting
Published in Archives of Environmental & Occupational Health, 2022
Mining of anthophyllite asbestos on Staten Island occurred locality on Ward Hill near Tompkinsville. We had previously sampled the exposure of the mine site in 1980 but now find it has been remediated and is largely covered by soil. During our re-visit we found several boulders of rock on the former mine floor that were partially covered by soil. The boulders measure up to 4 m across with an average diameter of about the size of a basketball (0.3 m) and were used as sample material. The multiple slickenside surfaces on and within the boulders exhibited striations with ridges and furrows, indicating that they were from a sheared zone produced by strike-slip faulting. The rock samples are therefore distinctly schistose. Behm12 describes the anthophyllite schist occurrence of Ward Hill as a 2 m thick ledge located ¾ up from the bottom to the top of the exposure with abrupt contacts with the enclosing serpentinite. More specifically he12 describes the serpentinite along Homer Street where we collected our samples as “contorted, and fractured” consisting largely of antigorite, talc, and anthophyllite with talc intimately associated with anthophyllite including small scales of talc between the folia of anthophyllite. None of the talc that we observed was fibrous although some talc was found intergrown with anthophyllite within fibers. We generally agree with Behm (1954)12 who proposed that the anthophyllite was derived from the enstatite-bastite component of the ultramafic peridotite protolith of the serpentinite. His chemical analysis of the anthophyllite indicates that the rock is composed largely of SiO2 (52%), FeO (11%), MgO (28%), and H2O (4%). These values are approximately consistent with an enstatite-orthoferrosilite solid solution (En75-Fs25) that was hydrated and replaced by an anthophyllite-cummingtonite-talc assemblage during the conversion of the peridotite and pyroxenite complex to serpentinite and anthophyllite. Magnesium rich orthopyroxenes are typical of ultramafic rocks so it is unlikely that ferrous pyroxene or their alteration products occur in the Staten Island mineral assemblage and have not been observed to date. Layers, lenses, and exclaves of enstatite pyroxenite are commonly found within peridotite bodies.