In cooperation with the Environmental Protection Agency

Solid-Phase Data from Cores at the Proposed Dewey 

Burdock Uranium In-Situ Recovery Mine, near 

Edgemont, South Dakota

By Raymond H. Johnson, Sharon F. Diehl, and William M. Benzel

Open-File Report 2013–1093

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia: 2013 

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Suggested citation: 

Johnson, R.H., Diehl, S.F., Benzel, W.M., 2013, Solid-phase data from cores at the proposed Dewey 

Burdock uranium in-situ recovery mine, near Edgemont, South Dakota: U.S. Geological Survey, 

Open-File Report 2013–1093, 13 p., http://pubs.usgs.gov/of/2013/1093/.

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iii

Contents

Abstract...............................................................................................................................................................1

Introduction.........................................................................................................................................................1

Methods..............................................................................................................................................................2

Results................................................................................................................................................................3

Observations.......................................................................................................................................................3

Acknowledgments...............................................................................................................................................4

References Cited................................................................................................................................................4

Figures

1. Map showing approximate location of study area ....................................................................................... 5

2. Map showing satellite imagery overlain with core locations ........................................................................ 6

3. Expanded view of Dewey area with core locations...................................................................................... 7

4. Expanded view of Burdock area with core locations ................................................................................... 8

5. Summary of mineralogy from the Fall River Formation in the Dewey area.................................................. 9

6. Summary of mineralogy from the Chilson Formation in the Burdock area ................................................ 10

7. Scanning electron microscopy and cathodoluminescence images of the same constituent quartz 

grains from the Fall River Formation in the Dewey area ........................................................................... 11

8. Scanning electron microscopy backscatter and cathodoluminescence images of the same constituent 

quartz grains from the Fall River Formation in the Dewey area................................................................. 12

9. Scanning electron microscopy backscatter and cathodoluminescence images of the same constituent 

quartz grains from the Chilson Formation in the Burdock area.................................................................. 13

Tables

1. Solid-phase geochemistry data ................................................................................................................link

2. X-ray diffraction data ................................................................................................................................link

Appendix Files

1. Carbon/sulfur data file ...............................................................................................................................link

2. Uranium isotopes ......................................................................................................................................link

3. Transmitted light images ...........................................................................................................................link

4. SEM images..............................................................................................................................................link

5. SEM elemental maps ................................................................................................................................link

 
Solid-Phase Data from Cores at the Proposed Dewey 

Burdock Uranium In-Situ Recovery Mine, near 

Edgemont, South Dakota

By Raymond H. Johnson, Sharon F. Diehl, and William M. Benzel

Abstract

This report releases solid-phase data from cores at the proposed Dewey Burdock uranium 

in-situ recovery site near Edgemont, South Dakota. These cores were collected by Powertech 

Uranium Corporation, and material not used for their analyses were given to the U.S. Geological 

Survey for additional sampling and analyses. These additional analyses included total carbon and 

sulfur, whole rock acid digestion for major and trace elements, 234U/238U activity ratios, X-ray 

diffraction, thin sections, scanning electron microscopy analyses, and cathodoluminescence. This 

report provides the methods and data results from these analyses along with a short summary of 

observations.

Introduction

Powertech Uranium Corporation (Powertech) has proposed to mine uranium at the Dewey 

Burdock site using in-situ recovery methods. The Dewey Burdock site is located in the 

southwestern region of the Black Hills of South Dakota (fig. 1). The uranium-recovery license 

application submitted by Powertech to the United States Nuclear Regulatory Commission (NRC) is 

publicly available and contains background information about the site along with technical details 

and baseline sampling data. The NRC application website is 

http://www.nrc.gov/materials/uranium-recovery/license-apps/dewey-burdock.html (with detailed 

application documents under the “application documents” link). A brief summary of the site history 

is provided by Powertech at http://www.powertechuranium.com/s/DeweyBurdock.asp.

At the Dewey Burdock site, uranium occurs as roll-front ore bodies in several sandstone 

units of the Inyan Kara Group of Early Cretaceous Age. The Late Jurassic Morrison Formation

(shale) underlies the Inyan Kara Group. In the vicinity of the mine site, the Inyan Kara Group is 

composed of the Fall River Formation (upper sandstone unit) and the Lakota Formation (lower 

sandstone unit). The Lakota Formation is composed of the Chilson and the Fuson Members, with 

the Fuson Member occurring between the Fall River and Lakota Formations. The Fuson Member 

(shale) is considered a confining unit between the Fall River Formation and the Chilson Member of 

the Lakota Formation. Uranium roll-front deposits occur in the Fall River Formation and the 

Chilson Member of the Lakota Formation. 

In 2007, Powertech completed several exploration holes that included core collection. Much 

of the core they collected was not used for their own analyses and was given to the U.S. Geological 
2

Survey (USGS) for additional sample analyses and long-term storage. These analyses were

completed with funding from the U.S. Environmental Protection Agency (EPA) Region 8’s 

Regional Applied Research Effort (RARE) program. The EPA is responsible for evaluating the site 

through its underground injection control program (http://www.epa.gov/region8/water/uic) and 

Powertech has submitted a separate permit application to EPA (see documentation in a link within 

the above EPA website). 

Sampling was completed at 31 selected core locations for total carbon and sulfur, whole 

rock acid digestion for major and trace elements, 234U/238U activity ratios (AR), X-ray diffraction

(XRD), thin sections, scanning electron microscopy (SEM) analyses, and cathodoluminescence. 

Locations of these cores are provided in figures 2, 3, and 4, and latitudes and longitudes are shown 

in table 1. These location maps are similar to maps of well samples provided in Johnson and others 

(2012). A well from those previous maps is shown in figures 3 and 4, for reference. The following 

sections discuss all of the analyses methods, data results, and a few general observations.

Methods

Total sulfur and carbon concentrations as weight percent were analyzed by the EPA at their 

laboratory in Ada, Oklahoma. Replicate analyses were performed for several samples and the 

values for one standard deviation of error are provided along with the average carbon and sulfur 

concentration (Appendix 1). Samples were analyzed using a ThermoScientific Flash 2000 CHNS-O 

analyzer. The samples were combusted at greater than 1,200°C, and the resulting combustion gases 

were swept into a chromatographic column by a carrier helium gas. Gases were separated in the 

column and detected by a thermal conductivity column. Five blank analyses were found to be 

below detection limits (Appendix 1). Total sulfur was analyzed using ASTM method D4239-11

(ASTM, 2011) and total carbon was analyzed using ASTM method D5373-08 (ASTM, 2008).

Uranium concentrations and 234U/238U activity ratios were measured by Dr. Michael 

Ketterer at the Northern Arizona University in Flagstaff, Arizona. Details on the analytical 

procedures can be found in Appendix 2. In addition, three samples were analyzed in duplicate with 

no differences being greater than 7 percent (Appendix 2). 

Whole rock analyses were completed at the USGS Central Mineral and Environmental 

Resources Science Center (CMERSC) Laboratories in Denver, Colorado. Rock and sediment 

samples were prepared by air drying and grinding to less than 150 microns (Taylor and 

Theodorakos, 2002) and then digested using multiple acids. The elemental concentrations in the 

digestion fluid were analyzed using inductively coupled plasma–mass spectroscopy (ICP–MS) with 

the procedure described by Briggs and Meier (2002).

Mineral phases were identified using X-ray diffraction analysis with Material Data Inc. 

(MDI) Jade (version 9.1) search-match software from the International Centre for Diffraction 

Data’s “2009 PDF-4” and the Inorganic Crystal Structure Database developed cooperatively by the 

National Institute of Standards and Technology and Fachinformationszentrum Karlsruhe. Semiquantitative mineral estimates were calculated using MDI Whole Pattern Fit software, which 

simultaneously calculates a whole pattern fit and a Rietveld refinement of the minerals. Reference 

minerals are selected from the database; some of these reference materials are “structure” 

references that represent perfect crystals of the mineral, and other entries are more typical mineral 

specimens. Each reference contains a full crystallographic description of the mineral. A calculated 

model of the observed pattern is produced by nonlinear, least-squares optimization. The 

calculations, performed by the software, involve the application of various parameters to improve 

the fit of the model to the observed data. Modeling parameters include background reduction, 
3

profile fitting, and lattice constants. The software iterates and minimizes a residual error between 

the calculated X-ray diffraction patterns from the selected references in comparison to the 

measured scan of the sample. All data were normalized to 100 percent based on the identified 

minerals, within a 1-percent error. A full description of the Whole Pattern Fit algorithm is available 

from MDI. 

Core samples with elevated uranium concentrations from the Dewey Burdock site were 

selectively collected to identify uranium and vanadium mineralogy at the Denver Microbeam Lab. 

Polished thin sections of this core material were examined, using transmitted light microscopy, and 

a JOEL 5800LV scanning electron microscope (SEM) with an Oxford ISIS energy dispersive X-ray 

spectrometer (SEM/EDS). Because uranium did not occur as discrete minerals in the Burdock 

sample(s), element intensity maps, also known as element distribution maps, were gathered on an 

electron microprobe (EMPA) to determine the spatial distribution of uranium in carbonaceous 

material. In these element maps, cool blue colors denote lower concentrations of an element, and 

bright green to yellow and red colors signify higher concentrations. In addition, scanning electron 

microscope cathodoluminescence (SEM–CL) images were acquired on the SEM with a Centaurus 

CL detector and photomultiplier, operated at 20 kilovolts (kV) and 10 nanoamps (nA), to identify 

radiation damage halos in quartz grains.

Results

All of the resulting data from total sulfur and carbon, uranium isotopes, and whole rock

analyses are provided in table 1. Table 1 also indicates the depths for all of the samples. The 

original carbon/sulfur analyses data file from the EPA is provided in appendix 1, which includes 

quality assurance/quality control (QA/QC) sampling with duplicates, blanks, and an internal 

standard. The original data file on 234U/238U activity ratios is provided in appendix 2, which 

includes QA/QC data from duplicate samples. X-ray diffraction analyses with comments are 

provided in table 2. The mineralogy from the Dewey Burdock core thin sections and SEM analyses 

is summarized in figs. 5 and 6. Results of cathodoluminescence in the Fall River Formation in the 

Dewey area are shown in figs. 7 and 8, and results of cathodoluminescence in the Chilson 

Formation in the Burdock area are shown in fig. 9. Selected additional core images are provided in 

appendices 3 through 5 (transmitted light, SEM images, and SEM elemental maps, respectively)

with file names matching the sample names in table 1. 

Observations

The primary purpose of this report is to release data. However, in looking at the data, major 

differences in the Dewey and Burdock areas are quite significant. Overall, the samples from the 

Dewey area (Fall River Formation, DB07-32 series) have higher calcite concentrations, no organic 

carbon is seen in SEM images, and radiation damage halos are seen in the SEM–CL images (which 

indicates the past presence of uranium that has later been dissolved away, leaving radiation damage 

on quartz grains). In addition, vanadium concentrations are quite high in the uranium ore samples 

(DB07-32-4C-3, 4, and 5). The Burdock area samples (Chilson Formation, DB07-11 series) have 

lower calcite concentrations, more organic carbon seen in SEM images, and lower vanadium 

concentrations in the uranium ore samples (DB07-11-14C-5, 6, and 7). In addition, the SEM 

elemental maps in the Burdock area show uranium that is sorbed to the organic carbon and 

cathodoluminescence results do not show any radiation damage halos.
4

Acknowledgments

The authors thank John Horton for his geographic information system (GIS) assistance in 

preparing the map figures and Heather Lowers in the USGS Denver Microbeam Lab for doing the 

SEM elemental mapping. 

References Cited

ASTM Standard D4239-11, 2011, Standard test methods for sulfur in the analysis sample of coal 

and coke using high-temperature tube furnace combustion: ASTM International, West 

Conshohocken, Penn., 4 p., DOI: 10.1520/D4239-11, accessed February 04, 2013, at 

http://www.astm.org/.

ASTM Standard D5373-08, 2008, Standard Test Methods for Instrumental Determination of 

Carbon, Hydrogen, and Nitrogen in Laboratory Samples of Coal: ASTM International, West 

Conshohocken, Penn., 9 p., DOI: 10.1520/D5373-08, accessed February 04, 2013, at

http://www.astm.org/. 

Briggs, P.H., and Meier, A.L., 2002, The determination of forty-two elements in geological 

materials by inductively coupled plasma–mass spectrometry, chap. I of Taggart, J.E., ed., 

Analytical methods for chemical analysis of geologic and other materials, U.S. Geological 

Survey: U.S. Geological Survey Open-File Report 02–223-I, 14 p. (Also available at 

http://pubs.usgs.gov/of/2002/ofr-02-0223/I20NAWQAPlus_M.pdf.) 

Johnson, R.H., 2012, Geochemical data from groundwater at the proposed Dewey Burdock 

uranium in-situ recovery mine, Edgemont, South Dakota: U.S. Geological Survey, Open-File 

Report 2012–1070, 11 p. (Also available at http://pubs.usgs.gov/of/2012/1070/.) 

Taylor, C.D., and Theodorakos, P.M., 2002, Rock sample preparation, chap. A1 of Taggart, J.E., 

ed., Analytical methods for chemical analysis of geologic and other materials, U.S. Geological 

Survey: U.S. Geological Survey Open-File Report 02–223-A1, 7 p. (Also available at 

http://pubs.usgs.gov/of/2002/ofr-02-0223/A1RxSampPrep_M.pdf.) 
5

Figure 1. Map showing approximate location of study area.
6

Figure 2. Map showing satellite imagery overlain with core locations. White 

boxes indicate locations of expanded views for figures 3 and 4.
7

Figure 3. Expanded view of Dewey area with core locations. Location of well 

687 is included for reference.
8

Figure 4. Expanded view of Burdock area with core locations. Location of well 

688 is included for reference.
9

Figure 5. Summary of mineralogy from the Fall River Formation in the Dewey area.
10

Figure 6. Summary of mineralogy from the Chilson Formation in the Burdock area. (qtz, quartz; μm, micrometers) 

Carbon, sulfur, insoluble residue in

pressure solution seam (stylolite)
11

• Constituent quartz grains show varying cathodoluminescence (CL) = different source areas and different internal 

chemistry

• Quartz overgrowths (QO) are dark = no CL; therefore a different generation of quartz cement

• Pale-gray halos (double arrows) within quartz grains suggest radiation damage rims 

Figure 7. Scanning electron microscopy (SEM, left) and cathodoluminescence (CL, right) images of the same constituent quartz (qtz) grains from the Fall River 

Formation in the Dewey area (sample 32-4C-4, 567'11" to 570'2"). Radiation damage halos (indicated by double arrows) suggest places that uranium was 

formerly present, but has since been locally remobilized. Grains are subrounded to angular, with the degree of rounding suggesting varying transport distance. 

The contrasting cathodoluminescence of the quartz grains are evidence of different geologic source terrains. Cathodoluminescence is dependent on trace 

metal content in the quartz. Aluminum is a common trace metal in quartz, and it varies on orders of magnitude. Note that the euhedral quartz overgrowths

(QO) are nonluminescent; this clearly demonstrates that the overgrowths precipitated on these grains post deposition, and they lack luminescing trace metals.

QO QO
12

Figure 8. Scanning electron microscopy (SEM) backscatter (left) and cathodoluminescence (right) images of the same constituent quartz (qtz) 

grains from the Fall River Formation in the Dewey area (sample 32-4C-4, 567'11" to 570'2"). Microfractures exhibit radiation damage halos (white 

area along microfractures). Radiation damage halos suggest places that uranium was formerly present, but has since been locally remobilized.
13

Figure 9. Scanning electron microscopy (SEM) backscatter (left) and cathodoluminescence (right) images of the same constituent quartz grains from the 

Chilson Formation in the Burdock area (sample 11-11C-6, 436'10.5" to 441'1'). Grains are subrounded to angular, with the degree of rounding suggesting

varying transport distance. The contrasting cathodoluminescence of the quartz grains is evidence of different geologic source terrains. 

Cathodoluminescence is dependent on trace metal content in the quartz. Aluminum is a common trace metal in quartz, and it varies on orders of

magnitude. Note that the euhedral quartz overgrowths (QO) are nonluminescent; this clearly demonstrates that the overgrowths precipitated on these 

grains post deposition, and they lack luminescing trace metals. (μm, micrometers)