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Forum on the Geology of Industrial Minerals, Saturday, October 10, 9:00 AM, Session 2

  • 1.  Forum on the Geology of Industrial Minerals, Saturday, October 10, 9:00 AM, Session 2

    Posted 10-02-2020 12:22 PM
    Steven Stokowski is inviting you to a scheduled Zoom meeting.
    Topic: Forum on the Geology of Industrial Minerals,  Session 2
    Time: Saturday, Oct 10, 2020 09:00 AM Eastern Time (US and Canada)
    Join Zoom Meeting
    Meeting ID: 870 4118 2266
    Wednesday, September 30th presentations:
    9:00 AM - 9:05 Welcome
    9:05 - 9:35 PM, Roger S. Austin, PhD, PG, Milledgeville, GA, "Bauxite, Kaolin, a Meteor, Volcanism, and the Early Tertiary Super-Pluvial Climate in Georgia"
    9:40 – 10:10 PM, Steve Stokowski, Stone Products Consultants, Lawrenceville, GA,  "Uses for Quarry Fines from Aggregate Plants in the Southeast"
    10:15 – 10:45 PM, W. Crawford Elliott, PhD, Georgia State University, Daniel J. Gardner, Georgia State Univ., Parkash Malla, PhD, Thiele Kaolin Co., Ed Riley, Thiele Kaolin Co., & Ya Peng Yu, PhD, NanoEarth, Virginia Institute of Technology and State University, "Rare Earth Minerals in Kaolin Grit Fraction"
    10:45 – 11:00 PM, Questions and Answers
    Bauxite, Kaolin, a Meteor, Volcanism, and the Early Tertiary Super-Pluvial Climate in Georgia
    Roger S. Austin, PhD, PG 
    Geologist and Mining Consultant, Milledgeville, GA 
    Bauxite and kaolin laterites developed across middle Georgia and the adjoining coastal states in the Early Tertiary as the great Cretaceous sea retreated and exposed ancient crystalline rocks and Late Cretaceous sedimentary strata. Sea level fluctuations brought new periods of inundation. Erosion of upland deposits provided bauxite- and kaolin-enriched detritus to form new sedimentary layers. Subsequent retreat of the sea exposed even these sediments to laterization. This 18 My episode lasted into the Early Eocene. Formation of bauxite and kaolin also took place in Australia, South America, Central Africa and elsewhere. The formation of the typical layered sequence of the bauxite-over-kaolin (gibbsite-over-kaolinite or AlOH₃-over-Al₄Si₄O₁₀(OH)₈), requires a heavy flux of ground water with extremely low concentrations of alkalis and silica. To achieve this globally requires a prolonged super-pluvial event. Consequences of the Chicxulub meteor or asteroid impact 66.0 Mya and the extraordinary volcanism of the Deccan plateau 67.4 Mya have been called on to explain the mass extinction as the Cenozoic Era began. Both would charge the atmosphere with particulate matter, CO₂, and SO₂. Acidic rainfall, elevated global temperatures, and acidified oceans may have resulted. Inference of warming and a Late Paleocene Thermal Maximum (LPTM) based on carbon and oxygen isotope ratios in ocean sediments could have been exaggerated by the lowering of heavy isotope ratios brought about by heavy rainfall. The long duration of the event might reflect an earlier climatic tipping point brought about by the two episodes. The LPTM could have begun then, peaked at the Late Paleocene, and declined thereafter. In the Southeastern US, the bauxite has been substantially resilicated to form kaolin. Kaolin also formed by resilication of bauxite. This kaolin can be differentiated from kaolin that formed beneath the early bauxite and kaolin formed from younger sedimentary deposits by their contrasting textures and minor mineral components.
    Uses for Quarry Fines from Aggregate Plants in the Southeast
    Steven J. Stokowski, CPG, PG
    Stone Products Consultants, Lawrenceville, GA
     Quarry fines, the material washed from construction aggregate, could potentially yield over 100 industrial products in the abrasive, agricultural, ceramic, construction, mineral co-product, mineral filler, and pollution-control categories. The potentially highest-volume uses are in construction, agriculture, and pollution control. The over 1-billion ton recoverable stockpiled resource is sustainable with the estimated 350-million tpy annual production.
    The materials usually have inherently high moisture contents, about 20-30% when recovered from a settlement pond and decreasing to 5-15% during stockpiling. Pond clays from sand and gravel processing have the highest moisture contents; associated flume sands have the lowest. Pond screenings from crushed stone or slag washing usually have about 20-25% moisture upon recovery. The fine materials can be dewatered with cyclones, thickeners, and filter presses or even rotary dried in a variable speed dryer.
    The optimum potential products take advantage of the fineness while minimizing the potentially negative impact of the high moisture content, or the presence of agglomerates in moisture-reduced fine products. High fineness materials are valuable in chemical applications or for intermixing with fine wet materials (such as in brick manufacture). A high moisture content can be beneficial during further processing, such as mineral recovery or chemical beneficiation, or if the material is added back into standard aggregate products.
    In the Southeastern US, successful products from quarry fines include these application areas: as manufactured soils and agricultural sands, as cement stabilized base in Inverted Pavement construction, as engineered concrete sand with improved shape and yield, as drying sand for sludge, and as feldspathic sand for a variety of Industrial Minerals applications.
    Rare-Earth Elements in Kaolin Grit Fraction
    W. Crawford Elliott1
    Daniel J. Gardner1
    Prakash Malla2
    Ed Riley2
    Ya Peng Yu3
    1. Geosciences Department, Georgia State University, Atlanta, GA,, 404-413-5756
    2. Thiele Kaolin Company, Sandersville GA 
    3. NanoEarth, Virginia Institute of Technology and State University, Blacksburg, VA
    The heavy mineral subfractions were separated from grit fractions from two kaolin producing units (Cretaceous Buffalo Creek Member of the Galliard Formation and the middle Eocene Jeffersonville Member of the Huber Formation) in the Georgia Coastal Plain. The total concentrations of the rare-earth elements varied from 0.16 (Jeffersonville Member) to 0.50 wt. % (Buffalo Creek). The heavy mineral subfractions were enriched in the heavy rare-earth elements (Y, Gd-Lu) from 10 to 150 times relative to their concentrations in the Upper Continental Crust (UCC).  This heavy rare-earth element enrichment differed from the typical enrichment pattern of the light rare-earth elements found in crustal rocks. The heavy mineral subfraction was composed of titanium oxide minerals (anatase, rutile), zircon, and trace staurolite through X-ray diffraction measurements.  Xenotime was observed using scanning electron microscopy with energy dispersive spectroscopy.  Xenotime contained 1 - 2.6 wt. percent of Dy, Er, Gd, and Yb.   Xenotime and zircon contained the rare-earth elements in these heavy mineral subfractions. The heavy mineral subfractions of kaolin grit comprised a novel domestic resource of the rare-earth elements.  
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    Steven J. Stokowski
    Co-Chair, FGIM Georgia