Libby Montana Vermiculite MineLibby Montana Vermiculite Mine

W.R. GraceW.R. Grace

Maps and geologic information from: Boettcher, A.L., 1966, The Rainy Creek alkaline-ultramafic igneous complex near Libby Montana J Geology v 75 p 526-553Libby, Montana, J. Geology, v. 75, p. 526 553.

Location ofLocation of Facilities

Libby Vermiculite MineLibby Vermiculite Mine

Rainy Creek PlutonPluton

Rainy Creek Pluton

Definitions – rock names

• Fenite – narrow hydrothermally altered zone f N t ti h d l i dof Na-metasomatism, hydrolysis, and

oxidation, with increased sodium, hydrous ili t d h titsilicates and hematite

• Biotitite – rock composed almost entirely of biotite

• Syenite – plutonic rock w/y plow Quartz, 10<P/A+P<35

Minerals• Biotite – K(Mg,Fe2+)3(AlSi3O10)(OH)2

• Hydrobiotite – formula about halfway in between Bt• Hydrobiotite – formula about halfway in between Bt and Vermiculite, considered to be a high T alteration product of Biotite (Boettcher, 1966)p ( , )

• Vermiculite –(Mg,Ca)0 3(Mg,Fe3+,Al)3(Al,Si)4O10(OH)4 - 8H2O(Mg,Ca)0.3(Mg,Fe ,Al)3(Al,Si)4O10(OH)4 8H2Ooriginated by leaching of biotite by ground waters (removal of alkalis and oxidation of Fe2+ to Fe3+(Boettcher, 1966)

• Amphiboles – useless byproduct (from hydrothermal y ( yalteration of pyroxene), more later

W R Grace wanted the vermiculiteW.R. Grace wanted the vermiculite

• Mostly in BiotititeMostly in Biotitite• Amphibole asbestos is intimately

associated with vermiculite but is uselessassociated with vermiculite, but is useless

Rainy Creek Pluton

Sheet silicate structuresVermiculite Structure

Expansion Processi lit hi d ll th- vermiculite was shipped all over the

US for processing

• Vermiculite is heated for a few seconds to 1100oC

• Water present in vermiculite structureWater present in vermiculite structure vaporizes to steam and forces layers of sheet silicate apartsheet silicate apart

• This creates the usable product

Unexpanded and Expanded p pVermiculite

Location ofLocation of Facilities

Uses of Expanded VermiculiteUses of Expanded Vermiculite

• InsulationInsulation• Fireproofing

B lki t• Bulking agents• Absorbents• Soil amendments• Industrial fillersIndustrial fillers• Packing material

Libby A hib lAmphibole analyses –

t F 3+note Fe3+

and Fe2+

From Gunter, et al., 2003, Composition … of amphiboles from Libby, MT, American y, ,Mineralogist, v. 88, p. 1970-1978.

Naming AmphibolesNaming Amphiboles

• Why should we care?Why should we care?• Only reibeckite, grunerite, anthophyllite,

actinolite and tremolite amphiboles areactinolite and tremolite amphiboles are regulated as asbestos by the US EPA

• Non-mineralogists call Libby amphibolesNon mineralogists call Libby amphiboles tremolite; are they, really?

• No, they are other amphiboles calledNo, they are other amphiboles called winchite or richterite

• Other amphibole asbestos minerals areOther amphibole asbestos minerals are just as bad, but are not regulated!

Naming AmphibolesNaming Amphiboles

• How is it done?How is it done?• Follow specific rules for assigning

elements in chemical analysis of anelements in chemical analysis of an amphibole to different sites in the formulaL k t l 1997 N l t f• Leake, et al., 1997, Nomenclature of amphiboles…, American Mineralogist, 82, 1019 10371019-1037.

Amphibole FormulaAmphibole FormulaAB2C5T8O22(OH)2

(Na K) (Ca Na Fe Mg) (Mg Fe Al) (Si Al) O (OH F)(Na,K)0-1(Ca,Na,Fe,Mg)2(Mg,Fe,Al)5(Si,Al)8O22(OH,F)2large medium small tetrahedral

Libby Amphiboles

• (Na.14K.13) (Ca1.25Na.73) (Mg4.24Fe3+.41Fe2+

.30)Si8.0O22(OH,F)

• (Na.32K.19) (Ca1.12Na.85) (Mg4.43Fe3+.34Fe2+

.18)Si8.0O22(OH1.63F.37)

Naming sodic-Naming sodiccalcic amphiboles

L k t lper Leake, et al., 1997

Mineralogist’s Names for Libby A hib lAmphiboles

• They are sodic-calcic amphiboles• Some classify as richteriteSome classify as richterite• Some classify as winchite

• They are not even in the same group as tremolite (a calcic amphibole), which is the name used in the media

Selections from Libby, Montana idvideo

• Big Sky Pictures• Produced directed and edited by DruryProduced, directed and edited by Drury

Gunn Carr & Doug Hawes-Davis

Libby, Montana Asbestos Cleanup Reaches Major Milestone With Mountaintop ParkMajor Milestone With Mountaintop Park

In this April 28, 2011 photo, D.C. Orr, a city councilman in Libby, Mont., stands in th iddl f t h b k d d hi t i t d iththe middle of a storage area, where bark and wood chips contaminated with undetermined levels of lethal asbestos were stored. Test results from huge piles of woodchips that were being sold from a Montana Superfund site for use in landscaping show they contain minimal levels of asbestos, according to a report p g y , g pFriday Jan. 13, 2012.The findings appear to offer a rare bit of relief for this town of Libby, where wide