U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2007–1241

Prepared in Cooperation with the U.S. Environmental Protection Agency

Selected Water-Quality Data for the Standard Mine,

Gunnison County, Colorado, 2006-2007
Front Cover: View of the Standard Mine facilities near Crested Butte, Colorado, taken from the Level 1 portal, July 2005.
Selected Water-Quality Data for the 

Standard Mine, Gunnison County, Colorado, 

2006-2007

By Philip L. Verplanck, Andrew H. Manning, M. Alisa Mast, Richard B. Wanty,

R. Blaine McCleskey, Todor Todorov, and Monique Adams

Open-File Report 2007–1241

U.S. Department of the Interior

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

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director

U.S. Geological Survey, Reston, Virginia 2007

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Suggested citation:

Verplanck, P.L., Manning, A.H., Mast, M. A., Wanty, R.B., McCleskey, R.B., Todorov, Todor, and Adams, Monique, 2007, 

Selected water-quality data for the Standard Mine, Gunnison County, Colorado, 2006-2007: U.S. Geological Survey

Open-File Report 2007-1241, 12 p.
iii

Contents

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

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

Location and Climate............................................................................................................................1

Purpose and Scope ..............................................................................................................................1

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

Methods...........................................................................................................................................................4

Sampling Sites.......................................................................................................................................4

Water-Chemistry Sampling .................................................................................................................9

Laboratory Methods.............................................................................................................................9

Quality Assurance and Quality Control ...........................................................................................11

References Cited..........................................................................................................................................12

Figures

1. Index map of Colorado with expanded view showing the Standard Mine.........................2

2. Topographic map of Elk Basin and vicinity...............................................................................3

3. Cross-sectional view of the Standard Mine workings ...........................................................5

4. Aerial photograph of Elk Basin showing surface-sample sites............................................6

5. Level 3 of the Standard Mine showing sample sites ..............................................................7

6. Level 5 of the Standard Mine showing sample sites ..............................................................8

7. Comparison of analytical results by ICP-AES and ICP-MS with A, barium

concentration, B, manganese concentration, and C, strontium concentration...............11

Tables

1. Sample site locations...................................................................................................................4

2. Methods of analysis and detection limits...............................................................................10

3. Water analyses of study samples.................................................. click here to open table 3

4. ICP-MS analyses of study samples ............................................... click here to open table 4
iv

Conversion Factors

Inch/Pound to SI

Multiply By To obtain

Length

inch (in.) 25,400. micrometer (μm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

square mile (mi2

) 259.0 hectare (ha)

square mile (mi2

) 2.590 square kilometer (km2) 

Volume

cubic inch (in3

) 16,390. microliter (μL)

Flow rate

inch per year (in/yr) 25.4 millimeter per year (mm/yr)

acre-foot per day (acre-ft/d) 0.01427 cubic meter per second (m3

/s)

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows: 

°F=(1.8×°C)+32

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 

(NAVD 88).

Horizontal coordinate information is referenced to the insert North American Datum of 1983 

(NAD 83).

Altitude, as used in this report, refers to distance above the vertical datum.

Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius (μS/cm at 

25 °C). Concentrations of chemical constituents in water are given either in milligrams per liter 

(mg/L) or micrograms per liter (μg/L).
Abstract

Mine drainage and underground water samples were 

collected for analysis of inorganic solutes as part of a 1-year, 

hydrogeologic investigation of the Standard Mine and vicinity.

The U.S. Environmental Protection Agency has listed the 

Standard Mine in the Elk Creek drainage near Crested Butte, 

Colorado, as a Superfund Site because discharge from the 

Standard Mine enters Elk Creek, contributing dissolved and 

suspended loads of zinc, cadmium, copper, and other metals 

to Coal Creek, which is the primary drinking-water supply for 

the town of Crested Butte.

Water analyses are reported for mine-effluent samples 

from Levels 1 and 5 of the Standard Mine, underground samples from Levels 3 and 5 of the Standard Mine, mine effluent 

from an adit located on the Elk Lode, and two spring samples 

that emerged from waste-rock material below Level 5 of the 

Standard Mine and the adit located on the Elk Lode. Reported 

analyses include field parameters (pH, specific conductance, 

water temperature, dissolved oxygen, and redox potential) and 

major constituents and trace elements.

Introduction

In 2006, the U.S. Environmental Protection Agency 

(USEPA) listed the Standard Mine in the Elk Creek drainage 

basin near Crested Butte, Colorado (fig. 1) as a Superfund Site 

because drainage from the Standard Mine enters Elk Creek, 

contributing dissolved and suspended loads of zinc, cadmium, 

copper and other metals to the stream. Elk Creek flows into 

Coal Creek, which is the main drinking-water supply for the 

town of Crested Butte. As part of the site characterization, the 

U.S. Geological Survey (USGS) was asked to characterize the 

ground-water flow system in the vicinity of the Standard Mine 

in order to assist the USEPA in evaluating remedial options for 

the mine. One aspect of the study was to collect water-quality 

samples from mined areas within the Elk Creek drainage.

Location and Climate

The Standard Mine lies within the upper Elk Creek 

drainage basin (Elk Basin), a roughly 1-mi2 alpine watershed 

located approximately 4 mi west-northwest of the town of 

Crested Butte in west-central Colorado (fig. 1). Land-surface 

elevations in Elk Basin range from 10,800 to 12,200 ft, and 

topographic gradients generally range from 0.2 to 0.6, typical 

of rugged mountain settings (fig. 2). Vegetation is subalpine to 

alpine, dominantly mixed spruce and fir forest or tundra. The 

closest meteorological stations are in the town Crested Butte 

at an elevation of 8,860 ft (http://www.wrcc.dri.edu) and at 

Crested Butte Ski Area about 6 mi to the east at an elevation 

of 10,160 ft (http://www.wcc.nrcs.usda.gov/snotel). Data from 

these stations indicate that Elk Basin has a mean annual air 

temperature of about 1°C and mean annual precipitation of 

about 31 in/yr, with about 65 percent of precipitation typically 

falling as snow. Snow cover generally persists from November 

through May. Elk Basin is drained by Elk Creek, a perennial 

stream and a tributary to Coal Creek.

Purpose and Scope

The purpose of this report is to present water-quality 

data from the ground-water investigation conducted from 

July 2006 to June 2007 in Elk Basin, Colorado. Use of these 

data will aid in characterization of the ground-water system 

in the study area. Data presented in this report include 

field measurements of pH, specific conductance, dissolved 

oxygen, redox potential (Eh), and water temperature; and 

laboratory determinations of major constituent and selected 

trace element concentrations. Water samples include seasonal sampling of the Standard Mine drainage, ground-water 

samples from inside the Standard Mine, Elk Mine effluent, 

and selected springs that emerge from waste-rock material.

Selected Water-Quality Data for the Standard Mine, 

Gunnison County, Colorado, 2006-2007

By Philip L. Verplanck, Andrew H. Manning, M. Alisa Mast, Richard B. Wanty, R. Blaine McCleskey,

Todor Todorov, and Monique Adams
Mt. Emmons

Standard

Mine

Daisy

Mine

Keystone

Mine

Peeler Lakes

Copley

Lake

Crested Butte

Scarp Ridge

Elk Cr.

Coal Cr.

Oh-Be-Joyful Cr.

Redwell Cr.

Slate

River

Nicholson

Lake

38o52'30"

38o55'00"

107o 107 00' o

05'

0 0.5 1MILE

0 0.5 1 KILOMETER

Colorado

Colorado

Plateau

Southern

Rocky

Mountains

Great Plains

Denver

Crested Butte

Figure 1. Index map of Colorado with expanded view showing location of the Standard Mine.

2 Selected Water-Quality Data for the Standard Mine, Gunnison County, Colorado, 2006-2007
Elk Basin 

107o05' 107o04' 107o03' 

38o52'

38o53'

0 0.5 1 MILE

0 0.5 1 KILOMETER

Base from U.S. Geological Survey Oh-Be-Joyful and Mt. Axtel Quadrangles, 1:24,000 (1961)

Figure 2. Topographic map of Elk Basin and vicinity.

Introduction 3
Acknowledgments

This work was done in cooperation with the USEPA. We 

greatly appreciate the efforts of Steve Renner, Jim Herron, and 

Jeff Graves of the Colorado Division of Reclamation, Mining, 

and Safety (CDRMS) for escorting us into the mine. We thank 

David L. Fey and JoAnn M. Holloway of the USGS for their 

constructive comments during the preparation and review of 

this report.

Methods

Sampling Sites

The largest mine within Elk Basin is the Standard Mine, 

which consists of five levels with multiple stopes and raises. 

A more-detailed description of the Standard Mine is provided 

in a Colorado Geological Survey report on the mine (Bird and 

Wood, undated). The adits are designated Levels 1, 2, 3, and 

5, in sequence from lowermost to uppermost (fig. 3). Levels 

Table 1. Sample site locations.

[Ft, feet; UG, underground ;m, meter; coordinates are Universal Transverse Mercator (UTM) coordinate system, North American Datum of 1983, Zone 13S]

Site name Northing

(m)

Easting

(m) Description Elevation (Ft)

EC-MSTD1 4305516.8 320123.7 Standard Mine, Level 1-portal 11,008

EC-MUSTD1 4305674.2 320315.2 Standard Mine, Level 2-waste-rock seep near collapsed portal 11,208

EC-MSTDL31 UG UG Standard Mine, Level 3-132 ft in from portal UG

EC-MSTDL32 UG UG Standard Mine, Level 3-145 ft in from portal UG

EC-MSTDL33 UG UG Standard Mine, Level 3-327 ft in from portal UG

EC-MSTDL34 UG UG Standard Mine, Level 3-386 ft in from portal UG

EC-MSTDL35 UG UG Standard Mine, Level 3-639 ft in from portal UG

EC-M11600 4305941.1 320666.6 Standard Mine, Level 5-portal 11,581

EC-M116001 UG UG Standard Mine, Level 5-546 ft in from portal, left drift UG

EC-M116002 UG UG Standard Mine, Level 5-228 ft in from portal UG

EC-M11400B 4305948.8 320403.8 Elk Lode-portal 11,380

EC-S1 4305935.9 320609.7 Seep from base of waste-rock pile below Level 5 adit 11,509

EC-S11 4305911.6 320345.2 Seep at waste-rock pile below Elk Lode portal 11,356

1, 2, and 3 are connected by a series of raises. The Level 5 tunnel, however, is not connected to the other levels. The Level 1 

and Level 5 portals are the only portals that consistently drain 

water. In August 2006, water was observed in Level 3 and 

drained to lower levels via raises.

Table 1 and figure 4 provide the locations of surface 

samples. Figures 5 and 6 show the location of samples collected inside the Standard Mine. Sample collection of the 

Level 1 portal (EC-MSTD1) was the most comprehensive 

and included samples in July, August, and October 2006 

and February, March, April, May, and June 2007. In July 

2006, a seep emanating from waste-rock material near the 

caved entrance to Level 2 was collected (EC-MUSTD1). 

In August 2006, five samples from Level 3 (EC-MSTDL31 

through 35) were collected between 132 and 639 ft in from 

the entrance (fig. 5), three samples from Level 5 (fig. 6) 

including the adit effluent (EC-M11600) and two inside the 

mine (EC-M116001 and 2), a seep emanating from wasterock material below the Level 5 adit (EC-S1), one sample 

from the collapsed Elk Lode portal (EC-M11400B), and 

one sample from waste-rock material below the Elk Lode 

(EC-S11).

4 Selected Water-Quality Data for the Standard Mine, Gunnison County, Colorado, 2006-2007
Level 1

Level 2

Level 3

Level 4

Level 5

0 0 

Figure 3. Cross-sectional view of the Standard Mine workings. Sketch from U.S. Environmental Protection Agency.
0

0 300 600 900 1200 1500

100 200 300 400 500

FEET

METERS

Elk Creek 

EC-S1 EC-S11 

EC-MSTD1 

EC-MUSTD1 

EC-M11600 EC-M11400B 

0

0 300 600 900 1200 1500 FEET

100 200 300 400 500 METERS

Elk Basin 

Level 5 portal 

Level 1 portal 

Level 2 portal 

Level 3 portal 

N 

Elk Lode 

portal 

Figure 4. Aerial photograph of Elk Basin showing surface sample sites.

6 Selected Water-Quality Data for the Standard Mine, Gunnison County, Colorado, 2006-2007
LEVEL 3

0

0 10 20

50 100 FEET

30 METERS

E

EC-MSTDL31

EC-MSTDL32

EC-MSTDL33

EC-MSTDL34

Figure 5. Level 3 of the Standard Mine showing sample sites. Draft mine map courtesy of Colorado Division of Reclamation, Mining, and Safety.
0

0 10 20

50 100 FEET

30 METERS

EC-M11600

EC-M116002

LEVEL 5

Fault-dip 

Figure 6. Level 5 of the Standard Mine showing sample sites. Draft mine map courtesy of Colorado Division of Reclamation, Mining, and Safety.
Water-Chemistry Sampling

Onsite measurements of pH, specific conductance, 

temperature, dissolved oxygen, and Eh were obtained. At 

each site the pH electrode calibration was checked and, when 

necessary, recalibrated using two buffers that bracketed the 

measured pH. Samples were filtered onsite through a syringe 

filter having a pore size of 0.45 μm. Several sample aliquots 

were collected for determination of concentrations of inorganic constituents and redox species (Fe+2/Fe+3). Container 

preparation and stabilization of filtered samples included 

an unfiltered, nitric acid acidified aliquot (RA) for totalrecoverable major cation and trace element determinations; a 

filtered, nitric acid acidified aliquot (FA) for dissolved major 

cation and trace element determinations; a filtered, nonacidified aliquot (FU) for anion and alkalinity determinations; 

and a filtered, hydrochloric acid acidified aliquot for iron 

redox species determinations. Bottles for FA and RA aliquots 

were presoaked in nitric acid, rinsed in distilled water, and 

prerinsed with sample water. Bottles for FU aliquots were 

presoaked in distilled water and prerinsed with sample water. 

Opaque bottles for iron redox aliquots were presoaked in 

hydrochloric acid, rinsed in distilled water, and prerinsed 

with sample water. Appropriate aliquots were acidified with 

ultrapure acid and then stored on ice until refrigerated.

Laboratory Methods

All reagents were of a purity at least equal to the 

reagent-grade standards of the American Chemical Society. 

Double-distilled deionized water, and re-distilled acids using a 

sub-boiling purification technique (Kuehner and others, 1972), 

were used in all preparations. The methods and detection limit 

for each analysis are summarized in table 2. USGS standard 

reference water samples and blanks were included with each 

sample suite for inductively coupled plasma atomic-emission 

spectroscopy (ICP-AES) and inductively coupled plasma-mass 

spectrometry (ICP-MS). Major cations (Ca, Mg, K, and Na) 

and silica and selected selected trace elements (aluminum, 

boron, barium, copper, iron, manganese, lead, strontium, and 

zinc) for total-recoverable and dissolved samples were determined using a Perkin Elmer Optima 3000TM ICP-AES (Briggs, 

2002). Trace elements for total-recoverable and dissolved 

samples were analyzed with the ICP-MS using a method 

developed by the U.S. Geological Survey (Meier and others, 1994; Lamothe and others, 2002). This method is used to 

directly determine the elements in the water samples without 

need for any preconcentration or dilution. Elemental detection 

limits are in the sub-parts per billion range (table 2), and the 

working linear range is six or more orders of magnitude.

Concentrations of major anions (Cl-

, F-, NO3

-

 and SO4

-

) 

were determined by ion chromatography (Theodorakos and 

others, 2002) using a Dionex DX500TM ion chromatograph 

with 5-μL and 10-μL sample loops. Standards were prepared 

from compounds of the highest commercially available 

purity. USGS standard reference water samples were used as 

independent quality-control standards. Alkalinity (as HCO3

-

) 

was determined using an Orion 960TM autotitrator and standardized H2

SO4 (Barringer and Johnsson, 1989). Samples 

were diluted as necessary to bring the analyte concentration within the optimal range of the method. Iron (II) redox 

species and total iron, in filtered, HCl-acidified samples, 

were determined using a modification of the FerroZineTM 

colorimetric method (Stookey, 1970; To and others, 1999) 

with a Hewlett Packard 8453TM diode array ultraviolet/visible 

(UV/VIS) spectrophotometer.

Methods 9
Table 2. Methods of analysis and detection limits

[mg/L, milligram per liter; μg/L, microgram per liter; IC, ion chromatography; ICP-MS, inductively coupled plasma-mass spectrometry; ICP-AES, 

inductively coupled plasma-atomic emission spectroscopy]

Element Detection limit Method Element Detection limit Method

Ag 1 μg/L ICP-MS Mn 0.2 μg/L ICP-MS

Al 20 μg/L ICP-AES Mo 2 μg/L ICP-MS

Al 2 μg/L ICP-MS Na 0.1 mg/L ICP-AES

As 1 μg/L ICP-MS Nb 0.2 μg/L ICP-MS

B 5 μg/L ICP-AES Nd 0.01 μg/L ICP-MS

Ba 1 μg/L ICP-AES Ni 0.4 μg/L ICP-MS

Ba 0.2 μg/L ICP-MS NO3

- 0.05 mg/l IC

Be 0.05 μg/L ICP-MS P 10 μg/L ICP-MS

Bi 0.2 μg/L ICP-MS Pb 50 μg/L ICP-AES

Ca 0.1 mg/L ICP-AES Pb 0.05 μg/L ICP-MS

Cd 0.02 μg/L ICP-MS Pr 0.01 μg/L ICP-MS

Ce 0.01 μg/L ICP-MS Rb 0.01 μg/L ICP-MS

Cl- 0.05 mg/l IC Sb 0.3 μg/L ICP-MS

Co 0.02 μg/L ICP-MS Sc 0.6 μg/L ICP-MS

Cr 1 μg/L ICP-MS Se 1 μg/L ICP-MS

Cs 0.02 μg/L ICP-MS SiO2 0.1 mg/L ICP-AES

Cu 10 μg/L ICP-AES SO4

- 0.05 mg/l IC

Cu 0.5 μg/L ICP-MS Sm 0.01 μg/L ICP-MS

Dy 0.005 μg/L ICP-MS Sr 1 μg/L ICP-AES

Er 0.005 μg/L ICP-MS Sr 0.5 μg/L ICP-MS

Eu 0.005 μg/L ICP-MS Ta 0.02 μg/L ICP-MS

F- 0.05 mg/l IC Tb 0.005 μg/L ICP-MS

Fe 20 μg/L ICP-AES Th 0.2 μg/L ICP-MS

Fe 2 μg/L FerroZine Ti 0.5 μg/L ICP-MS

Fe (II) 2 μg/L FerroZine Tl 0.15 μg/L ICP-MS

Ga 0.05 μg/L ICP-MS Tm 0.005 μg/L ICP-MS

Gd 0.005 μg/L ICP-MS U 0.1 μg/L ICP-MS

Ge 0.05 μg/L ICP-MS V 0.5 μg/L ICP-MS

Ho 0.005 μg/L ICP-MS W 0.5 μg/L ICP-MS

K 30 μg/L ICP-MS Y 0.01 μg/L ICP-MS

La 0.01 μg/L ICP-MS Yb 0.005 μg/L ICP-MS

Li 0.2 μg/L ICP-MS Zn 20 μg/L ICP-AES

Lu 0.1 μg/L ICP-MS Zn 0.5 μg/L ICP-MS

Mg 0.1 mg/L ICP-AES Zr 0.2 μg/L ICP-MS

Mn 10 μg/L ICP-AES

10 Selected Water-Quality Data for the Standard Mine, Gunnison County, Colorado, 2006-2007
Quality Assurance and Quality Control

Quality control included replicate samples, field equipment blanks, analyses by alternative methods, and calculation 

of charge imbalance. Replicate samples are two field-collected 

samples that are considered to be essentially identical in composition and are used to estimate variability in environmental 

data. Replicate samples were collected immediately following 

the environmental sample. Each replicate sample was processed through all the steps of the environmental sample using 

a new filter and clean equipment. Replicate samples were 

analyzed at the same time using the same instruments as the 

other samples collected during the same sampling trip. Analytical results of replicate samples are included in tables 3 and 

4, and follow the corresponding water sample (sample name 

ending with R). Most major, minor, and trace element replicate 

concentrations are within ±10 percent of the corresponding 

water-chemistry sample.

A field equipment blank is a sample prepared using 

deionized water passed through all the sampling and processing equipment. This type of sample is used to check for 

the potential contamination of the water-chemistry samples 

during collection, processing, handling, and analysis. Analytical results are included in tables 3 and 4, designated EB-01 

through EB-05 (Equipment Blank). All analytes were below 

analytical detection limits except for bicarbonate alkalinity, 

which was consistently measured at 2 mg/L, just above the 

reporting limit.

Concentrations of cations were determined by ICP-AES 

and ICP-MS, and if concentrations of trace elements were at 

least three times the detection limit, good agreement between 

ICP-AES and ICP-MS results was observed (fig. 7). Barium, 

manganese, and strontium were chosen for this comparison 

because the range in concentrations of these elements was 

within the working range of both analytical techniques.

Data for all samples with complete analyses were 

checked using the computer program WATEQ4F (Ball and 

Nordstrom, 1991) for charge imbalance (C.I.), using the following calculation:

 anions) sum cations (sum

- cations (sum * 100 anions) sum (percent) C.I.

+ =

where sum cations is the sum of the cations in milliequivalents per liter, and sum anions is the sum of the anions in milliequivalents per liter. The percent-charge imbalance reflects 

how well the major anions and cations balance and usually 

is an independent measure of the accuracy of the analytical 

techniques. The percent-charge imbalance was low (less than 

10 percent) for all samples (tables 3). 

0 5 10 15 20 25 30 35 40

0

5

10

15

20

25

30

35

40

0 100 200 300 400 500 600 700

0

100

200

300

400

500

600

700

0 5,000 10,000 15,000 20,000 25,000

0

5,000

10,000

15,000

20,000

25,000

Barium

C

B

ICP-MS, IN MICROGRAMS PER LITER ICP-MS, IN MICROGRAMS PER LITER ICP-MS, IN MICROGRAMS PER LITER

Strontium

A

ICP-AES, IN MICROGRAMS PER LITER

ICP-AES, IN MICROGRAMS PER LITER

ICP-AES, IN MICROGRAMS PER LITER

Manganese

Figure 7. Comparison of analytical results by ICP-AES 

and ICP-MS with A, barium concentration, B, manganese 

concentration, and C, strontium concentration. Diagonal line 

is 1:1 correspondence and dashed lines indicate 10-percent 

variation.

Methods 11
Lamothe, P.J., Meier, A.L., and Wilson, S.A., 2002, The 

determination of forty-four elements in aqueous samples by 

inductively coupled plasma-mass spectrometry, in Taggart, 

J.E., Jr., ed., Analytical methods for chemical analysis of 

geologic and other materials, U.S. Geological Survey: U.S. 

Geological Survey Open-File Report 02-223, chapt. H, 13 p.

Meier, A.L., Grimes, D.J., and Ficklin, W.H., 1994, Inductively coupled plasma-mass spectrometry—A powerful 

analytical tool for mineral resource and environmental 

studies [abs], in Carter, L.M.H., Toth, M.I., and Day, 

W.C., eds., U.S. Geological Survey Research on Mineral 

Resources—1994, Part A—Program and Abstracts, Ninth 

V.E. McKelvey Forum on Mineral and Energy Resources: 

U.S. Geological Survey Circular 1103-A, p. 67-68.

Stookey, L. L., 1970, FerroZine – a new spectrophotometric 

reagent for iron: Analytical Chemistry, v. 42, p. 779-781.

Theodorakos, P.M., d’Angelo, W.M., and Ficklin, W.H., 2002, 

Fluoride, chloride, nitrate, and sulfate in aqueous solution 

utilizing auto suppression chemically suppressed ion chromatography, in Taggart, J.E., Jr., ed., Analytical methods 

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

Geological Survey: U.S. Geological Survey Open-File 

Report 02-223, chapt. V, 7 p.

To, T.B., Nordstrom, D.K., Cunningham, K.M., Ball, J.W., and 

McCleskey, R.B., 1999, New method for direct determination of dissolved Fe(III) concentrations in acid mine waters: 

Environmental Science and Technology, v. 33, p. 807-813.

References Cited

Ball, J.W., and Nordstrom, D.K., 1991, User’s manual for 

WATEQ4F, with revised thermodynamic data base and test 

cases for calculating speciation of major, trace, and redox 

elements in natural waters: U.S. Geological Survey OpenFile Report 91-183, 189 p.

Barringer, J.L., and Johnsson, P.A., 1989, Theoretical considerations and a simple method for measuring alkalinity and 

acidity in low-pH waters by gran titration: U.S. Geological 

Survey Water-Resources Investigations Report 89-4029, 35 p.

Bird, D., and Wood, R., undated, History, geology, and 

environmental setting of the Micawber Mine and Elk Lode 

in the Ruby Mining District, Gunnison National Forest, 

Gunnison County, Colorado: Denver, Colorado Geological 

Survey Open-File Report (un-numbered).

Briggs, P.H., 2002, The determination of twenty-seven elements in aqueous samples by inductively coupled plasmaatomic emission spectrometry, in Taggart, J.E., Jr., ed., 

Analytical methods for chemical analysis of geologic and 

other materials, U.S. Geological Survey: U.S. Geological 

Survey Open-File Report 02-223, chapt. F, 11 p.

Kuehner, E.C., Alvarez, R., Paulsen, P.J., and Murphy, T.J., 

1972, Production and analysis of special high-purity acids 

purified by sub-boiling distillation: Analytical Chemistry, 

v. 44, p. 2050-2056.

12 Selected Water-Quality Data for the Standard Mine, Gunnison County, Colorado, 2006-2007