Search Results - "Raymond H. Johnson"

Cross-Hole and Vadose-Zone Infiltration Tracer Test Analyses to Determine Aquifer Reactive Transport Parameters at a Former Uranium Mill Site (Grand Junction, Colorado) by Raymond H. Johnson, Ronald D. Kent, Aaron D. Tigar, C. Doc Richardson, Charles J. Paradis, Paul W. Reimus

“…The U.S. Department of Energy Office of Legacy Management is responsible for the long-term care and maintenance of former uranium mill sites in the United…”
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Using Fission-Track Radiography Coupled with Scanning Electron Microscopy for Efficient Identification of Solid-Phase Uranium Mineralogy at a Former Uranium Pilot Mill (Grand Junction, Colorado) by Johnson, Raymond H., Hall, Susan M., Tigar, Aaron D.

“…At a former uranium pilot mill in Grand Junction, Colorado, mine tailings and some subpile sediments were excavated to various depths to meet surface…”
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Column-Test Data Analyses and Geochemical Modeling to Determine Uranium Reactive Transport Parameters at a Former Uranium Mill Site (Grand Junction, Colorado) by Raymond H. Johnson, Aaron D. Tigar, C. Doc Richardson

“…The long-term release of uranium from residual sources at former uranium mill sites was often not considered in prior conceptual and numerical models, as…”
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Single-Well Push–Pull Tracer Test Analyses to Determine Aquifer Reactive Transport Parameters at a Former Uranium Mill Site (Grand Junction, Colorado) by Raymond H. Johnson, Charles J. Paradis, Ronald D. Kent, Aaron D. Tigar, Paul W. Reimus

“…At a former uranium mill site where tailings have been removed, prior work has determined several potential ongoing secondary uranium sources. These include…”
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Modelling of palladium(II) adsorption onto amine-functionalised zeolite using a generalised surface complexation approach by Mosai, Alseno K., Johnson, Raymond H., Tutu, Hlanganani

“…The many uses of palladium in medicine, catalysts and other industries make it a very important precious element. Many industries using palladium discharge…”
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Modelled and Measured Adsorption of Rare Earth Elements onto Bentonite with Various Geochemical Conditions Using a Generalised Surface Complexation Approach by Mosai, Alseno K., Johnson, Raymond H., Tutu, Hlanganani

“…The demand for rare earth elements (REEs) is likely to outweigh supply. As such, every effort should be taken to salvage REEs from waste streams and other…”
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Combining fission-track radiography and scanning electron microscopy to identify uranium host phases by Sultana, Rakiba, Dangelmayr, Martin A., Paradis, Charles J., Johnson, Raymond H.

“…Residual solid-phase uranium from former mill tailings leachate can contribute to persistent concentrations of uranium in groundwater that exceed regulatory…”
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Desorption and Co‐Dissolution of Uranium‐Bearing Solids During Alkalinity‐Enhanced Flushing of Contaminated Sediments by Dangelmayr, Martin, Meurer, Cullen, Tigar, Aaron, Johnson, Raymond H., Paradis, Charles

“…Elevated uranium concentrations in groundwater remain a persistent challenge at contaminated sites. Several sites rely on natural flushing of uranium as a…”
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Modeling evaluation of the impact of residual source material on remedial time frame at a former uranium mill site by Kent, Ronald D., Johnson, Raymond H., Laase, Alan D., Nyman, Jennifer L.

“…Groundwater contamination at legacy uranium processing sites is an ongoing global challenge. Plumes at many uranium-contaminated sites are more persistent than…”
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Contaminant mobilization from the vadose zone to groundwater during experimental river flooding events by Sultana, Rakiba, Johnson, Raymond H., Tigar, Aaron D., Wahl, Timothy J., Meurer, Cullen E., Hoss, Kendyl N., Xu, Shangping, Paradis, Charles J.

“…Natural river flooding events can mobilize contaminants from the vadose zone and lead to increased concentrations in groundwater. Characterizing the mass and…”
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Field experiments of surface water to groundwater recharge to characterize the mobility of uranium and vanadium at a former mill tailing site by Paradis, Charles J., Johnson, Raymond H., Tigar, Aaron D., Sauer, Kirsten B., Marina, Oana C., Reimus, Paul W.

“…Characterizing the mobility of uranium and vanadium in groundwater with a hydraulic connection to surface water is important to inform the best management…”
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Elucidating mobilization mechanisms of uranium during recharge of river water to contaminated groundwater by Paradis, Charles J., Hoss, Kendyl N., Meurer, Cullen E., Hatami, Jiyan L., Dangelmayr, Martin A., Tigar, Aaron D., Johnson, Raymond H.

“…The recharge of stream water below the baseflow water table can mobilize groundwater contaminants, particularly redox-sensitive and sorptive metals such as…”
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Predictive Reactive Transport Modeling at a Proposed Uranium In Situ Recovery Site with a General Data Collection Guide by Johnson, Raymond H., Tutu, Hlanganani

“…Restoration of uranium in situ recovery (ISR) sites to predevelopment conditions is often very difficult. Future downgradient groundwater geochemistry can be…”
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Uncertainty and variability in laboratory derived sorption parameters of sediments from a uranium in situ recovery site by Dangelmayr, Martin A., Reimus, Paul W., Johnson, Raymond H., Clay, James T., Stone, James J.

“…This research assesses the ability of a GC SCM to simulate uranium transport under variable geochemical conditions typically encountered at uranium in-situ…”
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Alternative waste residue materials for passive in situ prevention of sulfide-mine tailings oxidation: A field evaluation by Nason, Peter, Johnson, Raymond H., Neuschütz, Clara, Alakangas, Lena, Öhlander, Björn

“…•Sewage sludge and fly ash were evaluated in novel field-scale dry cover amendments.•Sewage sludge was ineffective at mitigating ARD formation in underlying…”
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Refining the site conceptual model at a former uranium mill site in Riverton, Wyoming, USA by Dam, William L., Campbell, Sam, Johnson, Raymond H., Looney, Brian B., Denham, Miles E., Eddy-Dilek, Carol A., Babits, Steven J.

“…Milling activities at a former uranium mill site near Riverton, Wyoming, USA, contaminated the shallow groundwater beneath and downgradient of the site…”
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2006 Robley D. Evans Commemorative Medal--Ludwig Feinendegen by Johnson, Jr, Raymond H

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Using hydrogeology to identify the source of groundwater to Montezuma Well, a natural spring in Central Arizona, USA: part 1 by Johnson, Raymond H, DeWitt, Ed, Arnold, L. Rick

“…Montezuma Well is a natural spring located within a “sinkhole” in the desert environment of the Verde Valley in Central Arizona. It is managed by the National…”
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Sorption Testing and Generalized Composite Surface Complexation Models for Determining Uranium Sorption Parameters at a Proposed In-situ Recovery Site by Johnson, Raymond H., Truax, Ryan A., Lankford, David A., Stone, James J.

“…Solid-phase iron concentrations and generalized composite surface complexation models were used to evaluate procedures in determining uranium sorption on…”
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GIS and statistical approach to identify variables that control water quality in hydrothermally altered and mineralized watersheds, Silverton, Colorado, USA by Yager, Douglas B, Johnson, Raymond H, Rockwell, Barnaby W, Caine, Jonathan Saul, Smith, Kathleen S

“…Hydrothermally altered bedrock in the Silverton mining area, southwest Colorado, USA, contains sulfide minerals that weather to produce acidic and metal-rich…”
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