Prepared for the Bureau of Land Management

Review of Samples of Sediments, Tailings, and 

Waters Adjacent to the Cactus Queen Gold Mine, 

Kern County, California

By James J. Rytuba, Christopher S. Kim, and Daniel N. Goldstein

Open-File Report 2011-1034

U.S. Department of the Interior

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

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2011

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Suggested citation:

Rytuba, J.J., Kim, C.S., and Goldstein, D.G., 2011, Review of samples of 

sediment, tailings, and waters adjacent to the Cactus Queen gold mine, Kern 

County, California: U.S. Geological Survey Open-File Report 2011-1034, 34 p. 

[http://pubs.usgs.gov/of/2011/1034/].

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Although this report is in the public domain, permission must be secured from the individual 

copyright owners to reproduce any copyrighted material contained within this report.
iii

Contents

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

Background and Objectives...........................................................................................................1

Mining History and Geology ..............................................................................................................1

Cactus Queen Mine.......................................................................................................................1

Sample Locations and Methods........................................................................................................2

Sample Locations and Conditions ................................................................................................. 2

Field Sampling Methods....................................................................................................................2

Tailings and Sediments .................................................................................................................2

Water.............................................................................................................................................3

Analytical Methods............................................................................................................................3

Tailings and Sediment...................................................................................................................3

Waters...........................................................................................................................................4

Extended X-ray Absorption Fine Structure (EXAFS) Spectroscopy...............................................4

Results ..............................................................................................................................................5

Concentration of As in Tailings and Sediment...............................................................................5

Concentration of As Stream Water................................................................................................6

As Released in Leach Experiments...............................................................................................6

Speciation of Arsenic in Tailings....................................................................................................6

Conclusions ......................................................................................................................................7

Acknowledgments.............................................................................................................................8

References Cited ..............................................................................................................................8

Figures

Figure 1. Location map of the Cactus Queen gold mine in the western Mojave Desert.. ............19

Figure 2. Generalized geologic map showing location of volcanic fields and associated 

Au-Ag deposits including the Cactus Queen Au deposit located in the western part of 

the Mojave Desert, Kern County, California............................................................................20

Figure 3. Overview of the Cactus Queen mine, mill site and tailings on photographic 

base map. ..............................................................................................................................21

Figure 4. Topographic map the Cactus Queen Mine prior to development of the open 

pits and heap leach pad. ........................................................................................................22

Figure 5. Location of tailings, sediment, and water sample sites collected for 

geochemical analysis on the US BLM parcel adjacent to the Cactus Queen Mine. ...............23

Figure 6. View of tailings in the heap leach pad and the stream at the base of the 

tailings. ...................................................................................................................................24

Figure 7. Sediment in the linear stream constructed in tailings near the base of the heap 

leach pad. ...............................................................................................................................25

Figure 8. Water in the engineered stream channel collected from runoff on the heap 

leach pad (insert upper right) was sampled at two locations during a winter storm 

event. .....................................................................................................................................26
iv

Figure 9. Sediment in drainage channel located to the west of the heap leach pad. ..................27

Figure 10. Box plot of As concentration in tailings from the heap leach pad, and 

sediment in the drainage channel and stream. .......................................................................28

Figure 11. As concentrations as a function of distance in tailings from the heap leach 

pad, sediment from engineered stream channel, and the natural drainage channel...............29

Figure 12. Concentration of selected constituents in unfiltered and filtered rainwater 

runoff shown on a logarithmic scale........................................................................................30

Figure 13. Concentration of As in tailings increases with decreasing grain size to the S7 

size fraction, then decreases (A) and the surface area of the tailings increases with 

decreasing grain size (B). The concentration of As in water released during leach 

experiments increases with increasing concentration of initial As concentration in the 

tailings (C). The concentration of As released during leach experiments with 

simulated gastric fluid (SGF) increases with increasing initial As concentration in the 

tailings (D)...............................................................................................................................31

Figure 14. The percentage of As released in water varies as a function of grain size (A) 

and in simulated gastric fluid the percentage released increases linearly with 

decreasing grain size (B). The percent of As released in water as a function of 

surface area decreases with decreasing grain size (C) but in simulated gastric fluid 

the percentage released only gradually increases with decreasing grain size (D). .................32

Figure 15. EXAFS raw spectra and linear combination fits for size fractions of the 

08CT_T1 sample. ...................................................................................................................33

Figure 16. Color contour map of As concentration in stream sediment and soil samples 

from the NURE sample set. ....................................................................................................34

Tables

Table 1. Locations and descriptions of samples from the Cactus Queen Mine ...........................10

Table 2. Major and minor elements in tailings and sediments at the Cactus Queen Mine, 

 Kern County, California..............................................................................................................11

Table 3. Concentration of elements in sieved size fractions of tailings sample 08CT-T1 

 from the Cactus Queen Mine......... ...........................................................................................13

Table 4. Concentration of anions and selected cations in filtered waters from Cactus Queen 

Mine, Kern County, California ............................................................................................ 15

Table 5. Major- and minor- element concentration in unfiltered water at the Cactus Mine, 

 Kern County, California. .............................................................................................................16

Table 6. Major- and minor- element concentration in filtered water at the Cactus Queen Mine, 

 Kern County, California. .............................................................................................................17

Table 7. Arsenic speciation determined by EXAFS spectroscopy for selected grain size 

 fractions. ....................................................................................................................................18
v

Abbreviations, definitions, and datum used

Vertical and horizontal coordinate information is referenced to the North American Datum of 1927 (NAD 

27 CONUS).

As, generic shorthand for arsenic; does not denote speciation.

DOC, dissolved organic carbon.

DOM, dissolved organic matter.

EE/CA, Engineering evaluation/cost analysis for “non-time-critical removal actions,” as defined by the 

U.S. Environmental Protection Agency’s Comprehensive Environmental Response, Compensation, 

and Liability Act (CERCLA).

Hg, generic shorthand for mercury; does not denote speciation.

HgT,

Hg

total mercury (inorganic plus organic).

F,

mg/L, milligram per liter, approximately equivalent to one (1) part per million.

total mercury (inorganic plus organic) in a filtered sample (either 0.1 μm or 0.45 μm, as specified in 

the text).

μg/L, microgram per liter, approximately equivalent to one (1) part per billion.

ng/L, nanogram per liter, approximately equivalent to one (1) part per trillion.

ppm, parts per million, equivalent to mg/kg or μg/g.

SC, specific (electrical) conductivity, reported in units of millisiemens per centimeter (mS/cm).
Review of Samples of Sediments, Tailings, and 

Waters Adjacent to the Cactus Queen Gold Mine, 

Kern County, California

By James J. Rytuba1, Christopher S. Kim2, and Daniel N. Goldstein1

Introduction

Background and Objectives

The Cactus Queen Mine is located in the western Mojave Desert in Kern County, 

California (fig. 1). The Cactus Queen gold-silver (Au-Ag) deposit is similar to other AuAg deposits hosted in Miocene volcanic rocks that consist of silicic domes and associated 

flows, pyroclastic rocks, and subvolcanic intrusions (fig. 2). The volcanic rocks were 

emplaced onto a basement of Mesozoic silicic intrusive rocks. A part of the Cactus 

Queen Mine is located on Federal land managed by the U.S. Bureau of Land 

Management (BLM) (fig. 3). Staff from the BLM initially sampled the mine area (figs. 3 

and 4) and documented elevated concentrations of arsenic (As) in tailings and sediment 

(table 1). BLM then requested that the U.S. Geological Survey (USGS), in collaboration 

with Chapman University, measure and characterize As and other geochemical 

constituents in sediment, tailings, and waters on the part of the mine on Federal lands 

(fig. 4). This report is made in response to the request by the BLM, the lead agency 

mandated to conduct a Comprehensive Environmental Response, Compensation, and 

Liability Act (CERCLA) - Removal Site Investigation (RSI). The RSI applies to the 

potential removal of As-contaminated mine waste from the Cactus Queen Mine as a 

means of reducing As release and exposure to humans and biota. 

This report summarizes data obtained from field sampling of sediments, mine 

tailings, and surface waters at the Cactus Queen Mine on January 27, 2008. Our results 

provide a preliminary assessment of the sources of As and associated chemical 

constituents that could potentially impact humans and biota. 

Mining History and Geology

Cactus Queen Mine

The Cactus Queen Mine is located on the southwest slope of Middle Buttes, 10 

miles southwest of Mojave in the southern half of Sec. 17, T. 10 N., R. 13 W. (fig. 4). 

Gold was discovered at the Cactus Queen Mine site in 1934, and shortly after, Clifford 

 

1 U.S. Geological Survey, Menlo Park, Calif. 2 Chapman University, Orange, Calif.
2

Burton purchased the property and sold it to Cactus Mines Co. Ore was initially mined in 

a quartz vein occurring in dacite that strikes N. 45° E. and dips 35° SE with a width of 

about 16 ft (Julihn and Horton, 1937). Very fine free gold occurs in the quartz vein, 

along with finely disseminated cerargyrite. The vein lies along a major fault separating 

Mesozoic quartz monzonite bedrock from Tertiary quartz latite porphyry, and the main 

ore minerals include proustite, argentite, electrum, and finely divided free gold (Julihn 

and Horton, 1937). The mine operated from 1935 until WWII when underground mine 

operations were shut down by the War Production Board. During this period 230,000 

tons of ore with an average 0.35 ounces per ton of gold and 10 ounces per ton of silver 

were mined, resulting in a total production of 92,000 ounces of Au and 2,300,700 ounces 

of Ag (Terra-Gen Power, 2009). Some of the ore extracted at the Cactus Queen mine was 

hauled to the Tropico Mill for processing (Julihn and Horton, 1937). 

In 1986, Cactus Gold Mines Co. began open-pit mining combined with heap 

leaching in the Middle Buttes area. Open-pit mining ceased in 1992, but heap leaching of 

stockpiled ore continued through 1996. Total production during this period was about 

400,000 ounces of gold and 3,000,000 ounces of silver (Terra-Gen Power, 2009). The 

ores contained a significant amount of mercury (Hg) in the mineral corderoite and Hg 

was recovered as a byproduct (Blaske and others, 1991). Subsequent exploratory drilling 

in 1997 by Summo Minerals Corp. discovered an additional gold resource, which may 

contain as much as 600,000 additional ounces of gold; however, no further mining has 

occurred at the mine (Terra-Gen Power, 2009). 

Sample Locations and Methods

Sample Locations and Conditions

Samples were collected to assess the concentrations of As and associated 

elements in sediments, tailings, and waters on Federal land at the Cactus Queen Mine. 

The tailings occur in a heap leach pad, and stream sediment samples were taken from a 

channel constructed at the base of the leach pad (figs. 6 and 7). The tailings sample sites 

have a prefix T and sediment samples have a prefix S, as shown in figure 5 and listed in 

table 1. A naturally occurring drainage channel occurs below and runs roughly parallel to 

the tailings pad (figs. 6 and 7); sediment sample sites with prefix D were taken from this 

channel. Samples were collected at 500-foot intervals along the heap leach pad, the 

constructed stream channel beneath the tailings, and the natural drainage channel (fig. 5, 

table 1). During sampling a brief rainstorm resulted in significant runoff from the heap 

leach pad and resulted in water flow in the constructed channel at the base of the pad (fig. 

8). Samples of filtered and unfiltered water were collected at stream sites 08CT_S12 and 

08CT_S18 during this storm event (fig. 5, table 4). 

Field Sampling Methods

Tailings and Sediments

Samples consisting of 100 to 500 g of mine tailings were collected from the heap 

leach pad and sediments from the constructed and natural drainage channels below the 

heap leach pad at the Cactus Queen Mine. Tailings and sediment were stored and shipped 
3

in Ziploc® bags at ambient temperature. Before chemical analysis, samples were airdried in a laboratory fume hood at room temperature. One sample of tailings from the 

heap leach pad was weighed and then sieved into 10 size fractions to evaluate the 

concentration of As as a function of grain size. The sample was passed through a series of 

10 stainless steel 13-inch sieves featuring increasingly finer meshes with the aid of a RoTap Testing Sieve Shaker Model B from Tyler Industrial Products. The sample was 

agitated for a period of 30 minutes to insure effective size separation, resulting in 10 

distinct size fractions (table 3); no material was observed to pass through the 10th sieve.

Splits of 5-10 g from the initial bulk sample and from each fraction size weighing >5 g 

were analyzed by ICP-MS. 

Water

Stream samples were collected with new 60-mL sterile polypropylene syringes. 

Bulk water samples were subsampled for analysis of metal(loid)s and anions. Subsamples 

for metal(loid) determinations were acidified to pH<2 with trace metal (Ultrex, J.T. 

Baker)-grade HNO3 and stored in acid-washed, high-density polyethylene (HDPE) 

bottles. Subsamples for anion and alkalinity measurements were filtered, stored in HDPE 

bottles, and refrigerated at approximately 4°C until analysis, in accordance with USGS 

protocols for trace metals (http://pubs.water.usgs.gov/twri9A). Water samples were 

filtered with disposable 25 mm-diameter sterile cellulose acetate filters (0.45 μm and 

0.20 μm pore size) in the field for analysis of anions, alkalinity, and ICP-MS and -AES 

analysis. 

Water variables including pH, conductivity, and temperature were measured in 

the field with a battery-powered pH meter (Orion Model 290, with low-maintenance 

sealed gel triode electrode) and a specific conductivity meter (Orion Model 120). The pH 

triode, which has automatic temperature compensation, was also used for temperature 

measurements. Measurements were taken by placing the probe directly into the flowing 

stream water.

Analytical Methods

Tailings and Sediment

Multi-element analyses for all dry sediments and tailings were performed in the 

laboratories of ALS Chemex. Bulk samples were ground in a zirconia ring mill and 

subjected to a near-total four-acid digestion. Major elements were determined by ICPAES. Minor elements, other than Hg, were determined by ICP–MS. Mercury 

concentrations were determined by cold vapor atomic absorption spectroscopy (CVAAS) 

following methods similar to those described by Crock (1996) and O’Leary and others 

(1996). 

The bioaccessibility of As in each size fraction of the tailings that was prepared 

by sieving was evaluated by leach experiments. The leach experiments used water and 

simulated gastric fluid (SGF) to assess the amount of As released from the tailings. The 

water-based extractions simulate the natural leaching of As by rainfall and were 

conducted by exposing 3.0 g of each size fraction to 12.0 mL of slightly acidified water 
4

(pH=5.5, the pH of rainfall) for 18 hours. Samples were rotated end-over-end at room 

temperature. 

The in vitro simulated gastric fluid (SGF) extractions mimic the acidity of the 

human stomach at an internal core temperature. SGF was synthesized by mixing 2.0 L of 

deionized water with 60.06 g glycine and heating in a 37.0°C water bath. The SGF fluid 

was then acidified to pH 1.50 ± 0.05 using Ultrex concentrated nitric acid. A 0.5 g 

aliquot of each size fraction was then exposed to 50.0 mL SGF at pH 1.50 for a period of 

one hour to reflect human stomach pH and the time allotted for absorption in the 

stomach. Samples were agitated and incubated at 37.0°C, the body’s resting internal 

temperature.

Following exposure to each leach fluid, all samples were centrifuged at 3,000 

revolutions per minuteRPM for 15 minutes and the supernatants passed through 0.45 μm 

filters before acidification with a small volume of concentrated nitric acid. The fluid 

supernatants were then analyzed for extracted metal concentrations using ICP-MS. The 

elemental concentrations in the supernatants were then taken to reflect the corresponding 

amount of metals leached into rainwater or the body via the gastrointestinal system.

Waters

Alkalinity as CaCO3 was determined in the laboratory by titration with H2SO4

using Gran’s technique (Orion Research, Inc., 1978) within 2-4 days after sample 

collection. Sulfate, chloride, nitrate, and fluoride concentrations were determined by ion 

chromatography (Fishman and Pyen, 1979). 

Cations were analyzed by inductively coupled plasma–atomic emission 

spectrometry (ICP–AES) and inductively coupled plasma–mass spectrometry (ICP–MS). 

Ion chromatography and alkalinity analyses were performed by USGS laboratories under 

the direction of Paul Lamothe. The ICP-AES analyses were determined by USGS 

laboratories under the direction of Monique Adams. 

Extended X-ray Absorption Fine Structure (EXAFS) Spectroscopy

Bulk As K-edge EXAFS spectroscopic analysis was conducted at the Stanford

Synchrotron Radiation Lightsource (SSRL) at room temperature in fluorescence mode 

with a Lytle detector (for high-concentration samples, that is, [As]T > 1,000 ppm) or Ge 

30-element detector (for low-concentration samples, that is [As]T < 1,000 ppm). The

speciation of arsenic in the S3, S5, S7, and S9 size fractions of the size-separated tailings 

sample and the S9 size fraction following SGF extraction was then determined by 

comparison of its EXAFS spectrum with those from an arsenic model compound EXAFS 

library of 16 homogeneous As(-I), As(III), and As(V) phases including crystalline, 

amorphous, and sorbed compounds collected in transmission mode. Each model EXAFS 

spectrum, reflecting the distinct structural arrangement of arsenic in that particular 

sample, is unique and can therefore be utilized as a component phase in combination with 

other model spectra to characterize a heterogeneous, natural As-bearing sample. The 

EXAFS spectra of the mine waste samples were analyzed using a linear least-squares 

fitting method that has been employed in a wide range of environmental systems (Foster 

and others, 1998; Paktunc and others, 2004) to deconvolute the composite spectrum of 

the natural sample into the sum of its individual As-bearing components. 
5

EXAFS spectra were averaged, background-subtracted and fit over a k-range of 3-

12 Å-1 using the SixPack software program (Webb, S.M., 2005). Each model compound 

was first applied individually, with the compound yielding the best fit (that is, the lowest 

reduced χ2

 value, an indicator of the quality of fit) selected as the first component for 

subsequent fits. Additional model compound spectra were then individually paired with 

the first component to generate two-component fits, repeating the process until no more 

significant contributors, those representing ≥10 percent of the total fit, could be added 

that caused the reduced χ2 value to decline by ≥10 percent. The final fit, providing both 

the identification of the relevant arsenic species and their percent contributions to the fit, 

represents the EXAFS-determined arsenic speciation of that sample. This method, while 

providing a direct, non-destructive route to characterizing arsenic speciation, is limited to 

the spectra in one’s model compound database, has detection limits of ~100 ppm [As]T, 

and is considered to have errors of ±10 percent in the final quantitative phase 

determinations (Wang and others, 2008; Kim and others, 2000). 

Results

Concentration of As in Tailings and Sediment 

The concentrations of As in tailings in the heap leach pad at the Cactus Queen 

Mine range from 254 to 8,850 ppm with most samples containing over 2000 ppm As 

(table 2). The As concentrations are comparable to As concentrations in the initial 

samples collected by the BLM staff, which ranged from 783 to 7,890 ppm (samples 

CMH1-5, table 2). Sediments in the channel constructed at the base of the heap leach pad 

to collect runoff from the pad have comparable concentrations of As to that in the 

tailings, ranging from 775 to 6,690 ppm (fig. 5, table 2). Sediment samples from the 

natural drainage channel that occurs to the west of the heap leach pad also have elevated 

concentrations of As, 139 to 2,200 ppm, but are consistently lower in concentration than 

those in the constructed channel (figs. 5 and 9, table 2). Base metal concentrations in the 

tailings and sediments are all relatively low. The mean concentration of As is highest in 

sediment from the constructed channel in comparison to the mean concentration in the 

tailings and sediment in the natural drainage channel (fig. 10). The majority of the 

stream sediment samples from the constructed channel exceed the As concentrations 

present in the tailings from which the sediment is derived (fig. 11). The sediment 

samples from the natural drainage channel, however, are consistently lower in As 

concentration than either the tailings or the sediments from the engineered stream 

channel.

The results of grain size analysis are listed in table 3. The As concentration in the 

bulk sample was 4740 ppm. The As concentration in the largest grain size fraction was 

2,710 ppm and As concentration increased with decreasing grain size, reaching a 

maximum concentration of 8,540 ppm in the S7 size fraction 125 μm to 75 μm. The As 

concentration then decreased with decreasing grain size to 5,740 ppm in the smallest 

grain size fraction, 32 μm to 20 μm (fig. 13A). However, the surface area of the particles 

as measured by N2 adsorption using the BET method increased linearly with decreasing 

grain size (fig. 13B).
6

Concentration of As Stream Water 

During the rainstorm event, runoff from the tailings in the heap leach pad 

collected in and flowed along the constructed stream channel at the base of the pad. The 

two water samples collected from the stream channel have a pH of 7.2 and high 

concentrations of suspended sediment. The concentrations of As in the unfiltered water 

samples are extremely high and range from 84,000 to 97,600 μg/L (table 5, fig. 12). 

Concentrations of iron (Fe) and aluminum (Al) are also very high in the unfiltered water 

samples. Filtration of the runoff water by 0.45 μm and 0.2 μm filters effectively removes 

approximately 90% of the As, which is presumed to be in the solid phase (table 6, fig. 

11). However, with concentrations of As in the filtered samples between 9,540-10,100 

μg/L, the presumed dissolved As is still well above environmental regulatory levels. In 

contrast, more than 99 percent of Al and Fe is removed through filtration, with Fe 

concentrations below the detection limit in the 0.2 μm filtered fractions. This indicates 

that As in the water is not primarily sorbed to particles of Fe or Al oxyhydroxides. 

As Released in Leach Experiments 

The results of the leach experiments are presented in figures 13 and 14. The 

amount of As released from the water leach was relatively low, ranging from 0.64 to 1.08 

percent of the As present in the tailings (fig. 14A). The percentage of As released is 

inversely correlated with the amount of As in each grain size fraction with the least 

percentage released in the size fraction 125 μm to 75 μm which has the highest As 

concentration (S7, fig. 14A). However, when normalized to surface area, the percentage 

of As released in water decreases with decreasing grain size (fig. 14C). The percentage of 

As released from the SGF leaches ranges from 6 percent to 46 percent and increases with 

decreasing grain size (fig. 14B). However, when normalized to surface area, the trend is 

largely reduced, indicating that surface area is the primary factor affecting As solubility 

when exposed to gastric fluid (fig. 14D). Even after surface area normalization, however, 

there is still a slight inverse trend between particle size and As released, suggesting that 

other factors such as the chemical speciation of As may play a role in As solubility. 

Speciation of Arsenic in Tailings

Fits of the As EXAFS spectra collected from different size fractions of the sizeseparated tailings sample are shown in figure 15 with quantitative fits provided in table 7. 

All samples reveal a significant proportion of scorodite (FeAsO4•2H2O), while 3 of the 4 

samples also show evidence for the existence of As(V) sorbed to goethite (FeOOH) and 2 

of the samples indicate the presence of amorphous ferric arsenate. No strong trends can 

be observed in As speciation as a function of particle size, although there is a general 

decline in the proportion of scorodite present with decreasing particle size. Additionally, 

the finest grain size fraction (S9) is the only size fraction to contain all three identified 

phases and features the lowest proportion of scorodite of all samples. This suggests that 

at very fine particle sizes, scorodite (which is among the least soluble oxidized arsenic 

phases) may be more readily solublized, with released arsenic sorbing to goethite and/or 

forming amorphous ferric arsenate.

Comparison of the speciation of the S9 size fraction before and after the SGF 

extraction indicates that the SGF remobilizes all of the As sorbed to goethite and a 
7

portion of the amorphous ferric arsenate, while leaving the amount of scorodite relatively 

constant. This shows the differential solubility of the various As-bearing phases and 

might have implications for the variable percentages of As released as a function of 

(surface area-normalized) particle size in figure 14D. 

Conclusions

Highly elevated concentrations of As are present in the gold-mine tailings in the 

heap leach pad at the Cactus Queen Mine. The As concentrations in tailings are generally 

above 2,000 ppm and as high as 8,850 ppm. The As concentration in tailings is a function 

of grain size and increases with decreasing grain size, reaching a maximum concentration 

in the size fraction 250 μm to 125 μm. The As concentration decreases in the finest two 

grain size fractions but still remains higher than the As concentration in the bulk sample. 

In the 250 μm to 125 μm grain size fraction, the concentration is two times higher than in 

the bulk concentration (8,540 ppm and 4,740 ppm, respectively). During rainstorms, Asenriched sediment is eroded from the tailings in the heap leach pad and collects in the 

constructed stream channel at the base of the leach pad. The As concentration of 

sediment in this channel is typically above 4,000 ppm. The generally higher As 

concentration in the sediment as compared to that in the tailings results from erosion and 

release of fine-grained tailings particles that are enriched in As above that in bulk tailings 

concentrations. Unfiltered water samples from the stream channel sampled during a 

storm event had concentrations of As from 84,000 to 97,600 μg/L. The high As 

concentration in the unfiltered water results from the suspension of fine-grained Asenriched particles released from the tailings. In filtered waters, the As concentration 

decreases to about one-tenth of that present in the unfiltered water indicating that a 

substantial amount of the As present occurs as particulates. However, the concentration 

of As in the filtered waters is still relatively high (~10,000 μg/L) in both the 0.45 μm and 

0.20 μm filtered waters. 

The results of the water leach experiments indicate that only a small amount of 

the As in the tailings is released into water, typically less than 1.1 precent. In SGF leach 

experiments, much higher concentrations of As are released. The percentage of As 

released in the SGF leach increases with decreasing grain size of the tailings, ranging 

from 6 percent in the largest grain-size fraction to 46 percent in the finest grain size 

fraction. Thus the As phases in the tailings are bioaccessible if the pathway of exposure 

to humans and biota is by ingestion. 

The high concentrations of As in tailings and sediments at the Cactus Queen Mine 

are similar to other mineralized areas in the western Mojave Desert that have As-enriched 

sediments and soils present (fig. 16). Hydrothermal systems associated with emplacement 

of volcanic centers have mobilized As and concentrated it in and adjacent to Au-Ag 

deposits. Erosion of these As-enriched mineralized and altered areas has resulted in areas 

with anomalously high As in sediment and soils (fig. 16). In mine and mill site areas, 

such as the Cactus Queen Mine, processing of Au-Ag ores has resulted in tailings with 

exceptionally high As concentrations that are released during storm events into adjacent 

streams. The As-enriched sediments and tailings are of potential environmental concern 

to both humans and biota. 
8

Acknowledgments

The authors thank Peter Graves for his assistance in accessing the mine site and 

providing assistance during sampling. 

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of arsenic in gold ores and cyanidation tailings using X-ray absorption 

spectroscopy: Geochimica et Cosmochimica Acta, v. 68, no. 5, p. 969-983. 

Rytuba, J.J., 1996, Cenozoic metallogeny of California, in Coyner, A.R., and Fahey, P.L., 

eds., Geology and ore deposits of the American cordillera: Geological Society of 

Nevada Symposium Proceedings, Reno/Sparks, Nevada, p. 803-822. 

Smith, S.M., 1999, National Geochemical Database: U.S. Geological Survey Open-File 

Report 97-492. 
9

Terra-Gen Power, 2009, Alta-Oak Creek Mojave Project—Final Environmental Impact 

Report: Terra-Gen Power, LLC and Kern County Planning Department, accessed 

February 4, 2011at http://www.co.kern.ca.us. 

Troxel, B.W., and Morton P.K., 1962, Mines and mineral resources of Kern County, 

California: California Division of Mines and Geology, County Report 1, p. 120-

124. 

Tucker, W.B., 1923, Kern County, Mojave mining district: California Division of Mines 

and Geology, County Report 1, p. 43-45. 

Tucker, W.B., and Sampson, R.J., 1933, Kern County, Mojave mining district: 

California Division of Mines and Geology, County Report 31, p. 465-485. 

Wang, S.L., and Mulligan, C.N., 2008, Speciation and surface structure of inorganic 

arsenic in solid phases: A review. Environment International, v. 34, no. 6, p. 867-

879. 

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IFEFFIT: Physica Scripta, v. T115, p. 1011-1014. 
10

Table 1. Locations and descriptions of samples from the Cactus Queen Mine.

Field Latitude Longitude Sampling Notes

Number Date

Stream Samples

08CT_S0 34.96689 118.28435 1/27/08 Stream sediment sample directly below T1 sample

08CT_S3 34.97123 118.27912 1/28/08 Stream, some small rocks

08CT_S6 34.97026 118.28027 Stream, sand, light brown

08CT_S9 34.96925 118.28147 Stream, sand, light brown

08CT_S12 34.96836 118.28256 Stream sample

08CT_S15 34.96734 118.28377 Stream sample

08CT_S18 34.96639 118.28497 Stream sample

08CT_S21 34.96534 118.28618 Stream sample

08CT_S24 34.9645 118.28728 Stream sample

Drainage Channel

08CT_D4 34.97154 118.27944 1/28/08 Drainage Channel

08CT_D7 34.97055 118.28054 Drainage Channel

08CT_D10 34.96962 118.28163 Drainage Channel

08CT_D13 34.96858 118.28285 Drainage Channel

08CT_D16 34.96755 118.28391 Drainage Channel

08CT_D19 34.9665 118.28524 Drainage Channel

08CT_D22 34.96553 118.28635 Drainage Channel

08CT_D25 34.96472 118.28756 Drainage Channel

Tailings

08CT_T1 34.96688 118.28433 1/27/08 From large leach pad (not near breach)

08CT_T2 34.97112 118.27991 1/28/08 Tailings

08CT_T5 34.97046 118.28117 Tailings

08CT_T8 34.9692 118.28221 Tailings

08CT_T11 34.9683 118.28346 Tailings

08CT_T14 34.96733 118.28458 Tailings

08CT_T17 34.96636 118.2858 Tailings

08CT_T20 34.96537 118.28699 Tailings

08CT_T23 34.96448 118.28817 Tailings
11

Table 2. Major and minor elements in tailings and sediments at the Cactus Queen Mine, Kern County, California. 

[ppm: parts per million; %: percent]

Field Ag Al As Ba Be Ca Co Cr Cu Fe Hg K La Mg Mn Mo Na Ni P Pb S Sb Sc Sr Ti V Zn Au

Number ppm % ppm ppm ppm % ppm ppm ppm % ppm % ppm % ppm ppm % ppm ppm ppm % ppm ppm ppm % ppm ppm ppm

Stream Sediment

08CT-S0 3 1.43 5080 160 0.5 0.54 2 7 31 2.19 4 0.41 10 0.17 149 4 0.05 4 400 26 0.29 43 2 36 0.03 14 49

08CT-S3 2.8 1.16 5960 110 0.5 0.3 2 8 26 2.06 6 0.36 20 0.17 186 4 0.07 4 460 29 0.06 40 2 27 0.04 16 38

08CT-S6 2.5 1.54 4380 110 0.6 0.42 4 11 24 2.4 2 0.44 20 0.29 258 4 0.07 6 540 41 0.05 32 3 27 0.08 27 50

08CT-S9 2.2 1.27 2770 90 0.5 0.33 3 10 18 1.97 2 0.37 20 0.23 230 2 0.08 5 450 18 0.05 18 2 26 0.06 20 40

08CT-S12 3 0.97 6690 80 <0.5 0.28 2 7 22 1.93 3 0.29 20 0.18 171 3 0.05 5 620 22 0.05 37 2 23 0.04 17 39

08CT-S15 0.5 1.75 775 100 0.7 0.46 4 13 12 2.17 <1 0.47 20 0.38 321 2 0.08 8 510 10 0.02 6 4 33 0.1 31 43

08CT-S18 3.5 2.81 5070 420 0.7 0.35 3 9 29 2.6 7 0.72 20 0.21 213 4 0.12 6 420 24 0.34 38 3 54 0.06 23 44

08CT-S21 3.1 0.84 5360 170 <0.5 0.23 2 5 26 1.87 4 0.23 10 0.12 112 3 0.03 3 390 20 0.09 41 2 22 0.02 12 36

08CT-S24 3 0.87 4820 130 <0.5 0.28 2 6 25 1.77 3 0.25 10 0.15 133 3 0.04 3 370 21 0.08 39 2 24 0.03 13 37

Tailings

08CT-T2 1 2.07 852 120 0.7 0.61 5 15 16 2.53 <1 0.51 20 0.46 377 2 0.11 8 670 11 0.03 8 4 38 0.13 37 60

08CT-T5 5.5 2.29 8850 150 0.8 0.39 3 11 43 2.77 6 0.78 20 0.26 211 7 0.08 6 580 86 0.08 69 3 31 0.04 25 68

08CT-T8 0.3 1.88 254 90 0.7 0.43 6 13 11 2.19 <1 0.42 20 0.39 355 1 0.09 8 540 7 0.01 3 4 31 0.12 34 47

08CT-T11 2 1.99 2790 120 0.7 0.52 5 14 21 2.59 3 0.54 20 0.4 335 2 0.1 8 700 22 0.04 21 4 38 0.1 33 58

08CT-T14 1.1 1.9 1525 120 0.6 0.46 5 12 16 2.27 2 0.44 20 0.37 313 2 0.09 7 560 13 0.07 15 4 35 0.1 31 49

08CT-T17 3.4 1.99 2430 190 0.6 0.46 5 11 27 2.49 5 0.51 20 0.33 274 2 0.08 7 680 19 0.21 32 3 41 0.07 27 66

08CT-T20 2.6 2.29 2330 180 0.6 0.6 4 12 24 2.37 3 0.49 20 0.34 279 3 0.1 8 550 18 0.18 24 4 39 0.09 29 51

08CT-T23 2.3 1.53 4220 190 0.5 0.39 2 8 22 2.02 2 0.45 20 0.21 183 3 0.09 5 380 22 0.05 30 3 32 0.06 20 35

Sediment from Drainage

08CT-D4 0.2 2.35 139 110 0.9 0.78 9 18 17 3.16 <1 0.52 20 0.73 574 1 0.07 10 940 9 0.01 2 6 44 0.15 47 81

08CT-D7 0.5 2.1 1430 100 0.8 0.83 7 15 15 2.87 <1 0.45 20 0.63 452 1 0.08 8 800 14 0.02 10 5 43 0.12 42 67

08CT-D10 0.3 3.27 258 140 1 1.41 9 23 18 3.5 <1 0.63 20 0.88 582 1 0.14 11 780 11 0.02 5 7 74 0.18 56 79

08CT-D13 0.6 1.88 1410 120 0.6 0.62 4 12 11 2.18 <1 0.48 20 0.35 306 1 0.2 7 420 9 0.03 7 4 45 0.12 31 36

08CT-D16 0.2 2.64 259 110 1 1.83 8 17 16 3.18 <1 0.36 30 0.75 544 1 0.09 8 690 8 0.01 4 6 75 0.15 48 77

08CT-D19 0.7 1.94 2200 280 0.7 1 5 15 17 2.91 1 0.38 40 0.42 382 2 0.17 8 510 11 0.08 14 5 51 0.21 44 43

08CT-D22 1.3 1.93 2010 140 0.7 0.79 4 14 19 2.57 1 0.4 20 0.39 349 2 0.09 7 560 18 0.06 17 4 42 0.12 35 54

08CT-D25 1.3 3.22 1225 200 0.9 1.19 6 18 17 3.36 2 0.65 30 0.54 436 2 0.24 9 560 15 0.11 13 6 74 0.21 55 55
12

Table 2. Major and minor elements in tailings and sediments at the Cactus Queen Mine, Kern County, California-Continued.

[ppm, parts per million; %, percent]

Field Ag Al As Ba Ca Co Cr Cu Fe Hg K La Mg Mn Mo Na Ni P Pb S Sb Sc Sr Ti V Zn Au

Number ppm % ppm ppm % ppm ppm ppm % ppm % ppm % ppm ppm % ppm ppm ppm % ppm ppm ppm % ppm ppm ppm

BLM Samples

CMH 1 0.9 1.47 783 100 0.88 5 15 13 2.03 2 0.17 20 0.16 212 1 0.22 9 1180 14 0.08 9 2 171 0.07 46 45 0.02

CMH 2 3.5 0.66 1960 60 0.2 3 5 12 1.34 6 0.18 10 0.14 148 1 0.01 3 350 18 0.02 23 1 19 0.03 12 31 0.062

CMH 3 5 0.6 5540 40 0.11 9 4 96 1.32 3 0.14 10 0.05 67 9 0.02 13 190 50 0.82 38 1 10 0.01 5 101 0.123

CMH 4 10 0.87 7890 90 0.33 4 5 66 1.88 4 0.31 20 0.11 114 9 0.03 4 510 98 0.14 79 1 26 0.01 12 107 0.276

CMH 5 5.5 1.37 5130 140 0.43 5 8 49 2.75 4 0.46 30 0.27 246 5 0.01 6 700 52 0.13 61 2 34 0.04 22 105 0.178

CMWB 1 0.2 1.67 43 60 3.13 7 11 12 2.34 <1 0.18 10 0.62 359 <1 0.03 11 570 13 0.01 3 3 92 0.09 31 70 0.005

CMW 1 1.5 0.73 2270 80 0.37 2 4 14 1.41 4 0.17 10 0.15 142 2 0.01 2 330 12 0.04 22 1 23 0.03 12 30 0.067

CMW 2 2.9 0.49 3290 130 0.19 1 3 18 1.29 5 0.14 10 0.07 79 2 0.01 1 240 17 0.05 35 1 17 0.01 7 24 0.33

CMW 3 2.5 0.47 2310 80 0.16 1 3 12 1.17 3 0.14 10 0.06 101 1 0.01 3 200 14 0.06 19 1 16 0.01 7 21 0.077

CMF 1 4.8 0.45 1935 130 0.11 2 3 13 1.23 7 0.12 10 0.06 95 1 0.01 3 220 10 0.03 26 1 16 0.01 7 21 0.082

CMDITCH 

1

4.4 0.42 3210 200 0.13 1 2 18 1.39 7 0.14 10 0.04 60 3 0.02 2 170 11 0.09 30 1 16 0.01 5 19 0.307

CMDITCH 

2

5.6 0.59 3830 140 0.22 3 4 27 1.75 8 0.2 10 0.08 87 4 0.01 3 270 27 0.13 39 1 23 0.01 8 41 0.211

(*Not detected: B (<10ppm), Bi <2ppm, Cd <0.5 ppm, Ga (<10ppm), Th (<20ppm), Tl (<10ppm), U (<10ppm), W (<10ppm)
13

Table 3. Concentration of elements in sieved size fractions of tailings sample 08CT-T1 from the Cactus Queen Mine. 

[ppm: parts per million; %: percent]

Field Size Range Ag Al As Ba Be Bi Ca Cd Ce Co Cr Cs Cu Fe Ga Ge Hf

Number ppm % ppm ppm ppm ppm % ppm ppm ppm ppm ppm ppm % ppm ppm ppm

Bulk 5.88 6.56 4740 620 1.42 0.2 0.15 0.03 42.5 0.9 104 4.35 26.9 1.58 14.4 0.08 1.3

S1 > 2830 m 23 5.62 2710 470 1.35 0.11 0.06 0.09 36.7 0.4 8 2.83 84.3 2.64 12.8 0.09 1.4

S2 2830 m -1700 m 13.7 5.58 5660 450 1.55 0.14 0.09 0.02 45.7 0.8 101 4.45 24.4 1.6 13.35 0.08 1.3

S3 1700 m -1000 m 10.5 6.15 5910 620 1.34 0.16 0.13 0.04 44 0.9 7 4.73 47.4 2.11 13.6 0.09 1.3

S4 1000 m -500 m 7.55 7.08 6890 590 1.37 0.17 0.18 0.02 53.8 1.6 428 5.13 34.4 2.3 14.8 0.11 1.3

S5 500 m -250 m 7.88 7.53 7650 620 1.49 0.2 0.23 0.04 53.6 1.2 9 5.77 50.1 2.36 16.3 0.12 1.3

S6 250 m - 125 m 6.8 8.42 8110 710 1.45 0.2 0.31 0.04 52.9 1.3 90 6.31 57.7 2.33 17.5 0.12 1.2

S7 125 m - 75 m 6.33 8.69 8540 720 1.43 0.23 0.37 0.06 60.3 2.8 24 6.89 73.1 2.68 19.75 0.15 1.5

S8 75 m -45 m 7.06 10.05 6930 690 1.34 0.23 0.33 0.05 58.7 1.7 41 7.24 72.4 2.35 21.2 0.13 1.4

S9 45 m -32 m 7.9 10.85 5800 700 1.26 0.23 0.29 0.05 50.4 1.8 87 7.17 73.2 2.15 22.3 0.11 1.3

S10 32 m - 20 m 6.97 11.1 5740 690 1.29 0.22 0.31 0.09 62.2 1.7 28 6.74 75.3 2.3 20.5 0.13 1.2

Field Size Range Hg In K La Li Mg Mn Mo Na Nb Ni P Pb Rb S Sb Sc

Number ppm ppm % ppm ppm % ppm ppm % ppm ppm ppm ppm ppm % ppm ppm

Bulk 7.48 0.034 2.24 22.7 56.2 0.16 56 5.05 0.15 9.4 2.6 320 58.8 112 1.4 84.4 3.3

S1 > 2830 m 29.7 0.019 2.27 19.4 54 0.08 69 3.71 0.07 8.9 3.3 180 121.5 113 0.17 94.5 2.7

S2 2830 m -1700 m 13.9 0.032 2.12 23 57.5 0.14 49 4.29 0.11 8.3 2.6 450 42 117 0.63 100 2.8

S3 1700 m -1000 m 11.7 0.032 2.18 23.5 48.7 0.14 99 5.1 0.14 8.5 3.8 330 63.9 112 0.91 112.5 3

S4 1000 m -500 m 10.9 0.037 2.3 29.1 44.9 0.16 69 5.41 0.18 8.7 7.3 430 40.8 116.5 1.14 113.5 3.2

S5 500 m -250 m 10.9 0.044 2.49 28.4 44.3 0.17 86 5.91 0.21 9.5 4.3 470 57.1 124 1.33 118.5 3.6

S6 250 m - 125 m 10.9 0.048 2.68 26.8 40.1 0.19 70 5.92 0.27 10 3.9 520 45.1 107.5 1.75 117 3.9

S7 125 m - 75 m 10.2 0.051 2.75 31.9 44.5 0.48 97 6.84 0.29 12.8 40.2 530 56.5 138.5 1.88 128 4.7

S8 75 m -45 m 12.4 0.052 3 28.5 37.9 0.25 68 6.95 0.37 13.8 10.5 620 52.4 134.5 2.96 124.5 4.9

S9 45 m -32 m 12.5 0.048 3.2 22.7 33.9 0.21 63 7.59 0.44 12.6 13.8 640 55.4 128 3.82 120.5 4.6

S10 32 m - 20 m 12.6 0.045 3.27 30 33.2 0.2 79 7.98 0.46 13.1 14.8 630 62 125 4.07 111.5 4.8
14

Table 3. Concentration of elements in sieved size fractions of tailings sample 08CT-T1 from the Cactus Queen Mine-Continued.

[ppm: parts per million; %: percent]

Field Size Range Se Sn Sr Ta Te Th Ti Tl U V W Y Zn Zr

Number ppm ppm ppm ppm ppm ppm % ppm ppm ppm ppm ppm ppm ppm

Bulk 2 3.1 206 0.9 0.06 10.5 0.154 1.12 3.9 18 4.9 7.2 39 35.5

S1 > 2830 m 3 2.7 147.5 0.82 0.08 8.6 0.177 1.42 4 17 3.2 6.4 44 41.7

S2 2830 m -1700 m 2 2.8 147.5 0.84 0.07 10.3 0.141 1.18 4.9 15 3.5 7.5 28 35.5

S3 1700 m -1000 m 2 2.9 167 0.82 0.08 10.5 0.146 1.22 4.2 16 4.4 7.7 48 36.4

S4 1000 m -500 m 3 3.1 202 0.83 0.06 11.9 0.15 1.2 4.3 19 4.6 7.2 48 33.6

S5 500 m -250 m 3 3.3 227 0.97 0.08 12 0.167 1.26 4.5 19 7.5 8.2 61 36.6

S6 250 m - 125 m 3 3.5 263 0.93 0.09 12 0.183 1.37 4.4 22 6.4 7.4 74 31.3

S7 125 m - 75 m 5 3.9 269 1.22 0.09 13.3 0.224 1.38 4.2 25 8.1 9.2 86 37.6

S8 75 m -45 m 5 4.2 363 1.25 0.09 13.2 0.244 1.37 4.1 27 9 7.7 86 34.1

S9 45 m -32 m 4 4.2 436 1.11 0.08 12.6 0.226 1.27 4.2 31 8.9 6.5 101 31.9

S10 32 m - 20 m 4 4.6 436 1.14 0.08 13.2 0.242 1.23 4.4 30 9.3 7.2 96 31.5
15

Table 4. Concentration of anions and selected cations in filtered waters from Cactus Queen Mine, Kern County, California.

Sample pH Temp Conductivity Cl F NO3 SO4 CaCO3 Ca Fe K Li Mg Na

deg C μS ppm ppm ppm ppm ppm mg/L ug/L mg/L ug/L mg/L mg/L

08CT-S12 7.2 18 610 18.1 <.08 69.1 191 52.9 43.4 15.3 <5 3.87 52.2

08CT-S18 7.25 18 604 17.8 <.08 65.3 187.4 45.99 56.1 219 12.6 <5 4.24 57.9

08CT-FB 8.02 18 76 <.08 <.08 <.08 <.08 1.295 <0.1 <20 <0.1 <5 <0.1 <0.1
16

Table 5. Major- and minor- element concentration in unfiltered water at the Cactus Mine, Kern County, California.

Field No. Ag Al As Ba Be Ca Cd Ce Co Cr Cs Cu Dy Er Eu Fe Ga

ug/L ug/L ug/L ug/L ug/L mg/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L

08CT-S12 9.87 89100 84000 1060 9 223 2.34 308 95.4 72 3.87 1600 26.2 13.1 6.59 117000 30.2

08CT-S18 16.1 105000 97600 1630 8.8 213 2.25 353 96.2 88.8 7.43 1760 27.8 13.4 7.25 153000 41.5

08CT-FB <1 <2 13 <0.2 <0.05 <0.2 <0.02 < 0.01 <0.02 <1 < 0.02 <0.5 < 0.005 < 0.005 < 0.005 <50 < 0.05

Field No. Gd Ge Ho K La Li Lu Mg Mn Mo Na Nd Ni P Pb Pr Rb

ug/L ug/L ug/L mg/L ug/L ug/L ug/L mg/L ug/L ug/L mg/L ug/L ug/L mg/L ug/L ug/L ug/L

08CT-S12 33.8 2 4.66 53.2 136 87.2 1.5 45.2 5800 7.5 59.9 126 85.4 4.8 22.1 33.5 151

08CT-S18 35.6 2.6 4.89 59.5 156 108 1.6 49.8 5560 9.9 62.5 129 87.1 5.9 69.9 34.5 227

08CT-FB < .005 < 0.05 < .005 <0.03 < 0.01 < 0.1 < 0.1 <0.01 <0.2 < 2 <0.01 < 0.01 <0.4 < 0.01 <0.05 < 0.01 0.01

Field No. Sb Sc Se SiO2 Sm SO4 Sr Tb Th Ti Tl Tm U V Y Yb Zn

ug/L ug/L ug/L mg/L ug/L mg/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L

08CT-S12 3.49 38.1 19.5 251 28 144 697 4.75 5.79 96.8 3.7 1.65 34.7 140 135 10.4 3480

08CT-S18 5.88 39.3 20.4 249 28.8 144 734 5.06 10.1 282 4.8 1.74 36.6 179 146 11 3680

08CT-FB <0.3 < 0.6 < 1 < 0.2 < 0.01 < 2 < 0.5 < 0.005 < 0.2 < 0.5 <0.1 < 0.005 < 0.1 <0.5 < 0.01 < 0.005 <0.5

Field No. Zr

ug/L

08CT-S12 0.4

08CT-S18 0.99

08CT-FB < 0.2

Not detected: Bi, Nb, Ta, W
17

Table 6. Major- and minor- element concentration in filtered water at the Cactus Queen Mine, Kern County, California.

Field No. Ag Al As Ba Ca Cd Ce Co Cs Cu Fe Ge K Mg Mn Mo Na Ni P

ug/L ug/L ug/L ug/L mg/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L mg/L mg/L ug/L ug/L mg/L ug/L mg/L

08CT-S12 <1 12 9540 6.43 52.9 0.09 0.02 6.01 0.04 16.5 43.4 0.1 15.3 3.87 10.9 52.3 52.2 2.2 0.1

08CT-S18 1.29 8.3 10100 5.39 56.1 0.08 0.01 6.4 0.05 18 219 0.2 12.6 4.24 9.6 51.9 57.9 1.8 0.1

08CT-FB <1 <2 2 <0.2 <0.2 <0.02 <0.02 < 0.02 <0.5 <50 < 0.05 <0.03 < 0.1 <0.01 <0.2 < 2 <0.01 <0.4 < 0.01

Field No. Pb Rb Sb Se SiO2 SO4 Sr Ta Ti U V W Zn Zr

ug/L ug/L ug/L ug/L mg/L mg/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L

08CT-S12 0.07 6.07 8.61 15.5 4 184 69.4 0.09 2.8 0.9 2 0.56 262 1.5

08CT-S18 <0.05 6.56 10 14 4.4 162 62.9 < 0.02 2.6 0.9 2 0.52 7.3 < 0.2

08CT-FB 0.1 < .01 <0.3 < 1 < 0.2 < 2 < 0.5 < 0.02 < 0.5 < 0.1 <0.5 < 0.5 <0.5 < 0.2

Not detected: Be, Bi, Ce, Cr, Dy, Er, Eu, Ga, Gd, Ho, La, Lu, Nb, Nd, Pr, Sc, Sm, Tb, Th, Tl, Tm, Y, Yb
18

Table 7. Arsenic speciation determined by Extended x-ray absorption fine structure spectroscopy for selected 

grain size fractions.

Sample Name Size Range [As] (ppm) As Speciation R-factor

 Scorodite As(V)-goethite

Amorphous 

Ferric Arsenate

08CT_T1_S3 1000-1700 μm 5910 61% 40% 0.049

08CT_T1_S5 250-500 μm 7650 49% 46% 0.043

08CT_T1_S7 75-125 μm 8540 62% 44% 0.044

08CT_T1_S9 32-45 μm 5800 27% 41% 43% 0.045

08CT_T1_SGF_S9 32-45 μm 3109* 55% 52% 0.046

*Estimated based on SGF extractions.
19

Figure 1. Location map of the Cactus Queen gold mine in the western Mojave Desert. Gold mines are indicated by yellow squares and mercury (Hg) mines 

by red squares. 
20

Figure 2. Generalized geologic map showing location of volcanic fields and associated Au-Ag deposits including the Cactus Queen Au deposit located in the 

western part of the Mojave Desert, Kern County, California.
21

Figure 3. Overview of the Cactus Queen mine, mill site and tailings on photographic base map. The U.S. 

Bureau of Land Management parcel of land shown in yellow includes the northwest part of the mine and part 

of the heap leach pad. Samples collected by US BLM staff are shown in purple.
22

Figure 4. Topographic map of the Cactus Queen Mine before development of the open pits and heap leach 

pad. The U.S. Bureau of Land Management parcel is shown in yellow. Samples collected by BLM staff are 

shown in blue. 
23

Figure 5. Location of tailings, sediment, and water sample sites collected for geochemical analysis on the U.S. Bureau of Land Management parcel adjacent 

to the Cactus Queen Mine. The drainage ditch is the white linear line to the west of the heap leach pad containing samples with prefix D.
24

Figure 6. View of tailings in the heap leach pad and the stream at the base of the tailings at the Cactus Queen Gold Mine. In the foreground is a natural 

drainage channel also sampled in this study. 
25

Figure 7. Sediment in the linear stream constructed in tailings near the base of the heap leach pad at the Cactus Queen Gold Mine.
26

Figure 8. Water in the engineered stream channel collected from runoff on the heap leach pad (insert upper right) at the Cactus Queen Gold Mine was 

sampled at two locations during a winter storm event. Sample sites for sediment and water in the stream channel are shown in figure 5.
27

Figure 9. Sediment in drainage channel located to the west of the heap leach pad at the Cactus Queen Gold Mine. Sediment sample sites within the channel 

are shown in figure 5.
28

Figure 10. Box plot of As concentration in tailings from the heap leach pad and sediment in the drainage channel and stream at the Cactus Queen Gold Mine.
29

Figure 11. As concentrations as a function of distance in tailings from the heap leach pad, sediment from engineered stream channel, and the natural drainage 

channel at the Cactus Queen Gold Mine.
30

Figure 12. Concentration of selected constituents in unfiltered and filtered rainwater runoff from the Cactus 

Queen Mine shown on a logarithmic scale. Aluminum and iron (top two panels) decrease dramatically in 

filtered samples, suggesting both elements are exclusively present in the solid phase. Arsenic (bottom 

panel) shows a smaller decrease from unfiltered to filtered samples, suggesting a significant proportion 

(~10%) of the As in the water is dissolved or present as colloidal particles.
31

Figure 13. Concentration of As in tailings at the Cactus Queen Gold Mine increases with decreasing grain size to the S7 size fraction, then 

decreases (A) and the surface area of the tailings increases with decreasing grain size (B). The concentration of As in water released during 

leach experiments increases with increasing concentration of initial As concentration in the tailings (C). The concentration of As released during 

leach experiments with simulated gastric fluid (SGF) increases with increasing initial As concentration in the tailings (D).
32

Figure 14. The percentage of As released in water varies as a function of grain size (A) and in simulated gastric fluid (SGF) the percentage released 

increases linearly with decreasing grain size (B). The percent of As released in water as a function of surface area decreases with decreasing 

grain size (C) but in simulated gastric fluid the percentage released only gradually increases with decreasing grain size (D). 
33

Figure 15. Extended x-ray absorption fine structure (EXAFS) spectroscopy raw spectra (black) 

and linear combination fits (red) for size fractions of the 08CT_T1 sample from the Cactus 

Queen Gold Mine, specifically the (a) S3, (b) S5, (c) S7, (d) S9, and (e) S9 (residual after 

simulated gastric fluid (SGF) extraction). See table 7 for quantitative fitting results.
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Figure 16. Color contour map of As concentration in stream sediment and soil samples from the NURE sample set. Sample locations show by white 

circles. Highest concentrations of As shown by red and orange colors (maximum As concentration 5,000 ppm) and low As concentrations shown 

by blue and green colors (lowest As concentration 0.50 ppm). The locations of the Cactus Queen mine Au and other Au-Ag deposits in the 

western Mojave Desert are shown by triangles.