Scientific Investigations Report 2007–5248

Principal Locations of Metal Loading from FloodPlain Tailings, Lower Silver Creek, Utah, April 2004

U.S. Department of the Interior

U.S. Geological Survey

Prepared in cooperation with the 

UTAH DEPARTMENT OF ENVIRONMENTAL QUALITY, DIVISION OF WATER QUALITY
Cover photo: Metal-rich, acidic water draining away from piles of tailings along the flood 

plain of Silver Creek, Utah. Photograph taken looking southeast in April 2004 by Briant A. 

Kimball.
Principal Locations of Metal Loading from 

Flood-Plain Tailings, Lower Silver Creek, 

Utah, April 2004 

By Briant A. Kimball, Robert L. Runkel, and Katherine Walton-Day

U.S. Department of the Interior

U.S. Geological Survey

Prepared in cooperation with the

UTAH DEPARTMENT OF ENVIRONMENTAL QUALITY, DIVISION OF WATER QUALITY

Scientific Investigations Report 2007–5248
U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary 

U.S. Geological Survey

Mark D. Myers, Director

Reston, Virginia: 2007

For additional information write to:

U.S. Geological Survey

Director, USGS Utah Water Science Center

2329 W. Orton Circle

Salt Lake City, UT 84119-2047

Email: GS-W-UTpublic-info@usgs.gov 

URL: http://ut.water.usgs.gov/

For more information about the USGS and its products:

Telephone: 1-888-ASK-USGS

World Wide Web: http://www.usgs.gov/ 

Suggested citation:

Kimball, B.A., Runkel, R.L., and Walton-Day, Katherine, 2007, Principal locations of metal loading from flood-plain 

tailings, lower Silver Creek, Utah, April 2004: U.S. Geological Survey Scientific Investigations Report 2007–5248, 

33 p.

Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the 

U.S. Government.

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

to reproduce any copyrighted materials contained within this report.

Scientific Investigations Report 2007–5248
Contents

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

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

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

Description of the Study Area ............................................................................................................1

Previous Work .......................................................................................................................................3

Acknowledgments................................................................................................................................5

Methods for Mass-Loading Approach.......................................................................................................5

Tracer Injection and Synoptic Sampling...........................................................................................5

Load Calculation....................................................................................................................................6

Sample Classification...........................................................................................................................9

Discharge from Tracer Dilution ...................................................................................................................9

Chemical Variation of Synoptic Samples.................................................................................................11

Inflow Samples....................................................................................................................................11

Stream Samples..................................................................................................................................13

Principal Locations of Mass Loading .......................................................................................................17

Upstream from the Study Reach ......................................................................................................17

Upper Meadow Tailings Piles ...........................................................................................................17

Lower Meadow Tailings Piles...........................................................................................................19

Upstream from Pivotal Promontory Access Road.........................................................................19

Waste-Water Treatment Plant and Old Big 4 Mill Tailings...........................................................19

Other Sources......................................................................................................................................19

Comparison between 2002 and 2004 ...............................................................................................19

Summary and Conclusions.........................................................................................................................19

References Cited..........................................................................................................................................23

Figures

1. Location of the study reach indicating upper, middle, and lower injection reaches, 

location of changes in stream-water chemistry (colors indicate classification by 

cluster analysis), and principal locations of tailings, Silver Creek, Utah, April 2004.........2

2. Photographs of major sources of metal loading along the study reach, Silver 

Creek, Utah, April 2004.................................................................................................................4

3. Variation of bromide concentration at transport sites with time for (A) upper, 

(B) middle, and (C) lower injection reaches, Silver Creek, Utah, April 2004 .......................8

4. Variation of (A) discharge measured at U.S. Geological Survey streamflow-gaging 

station 10129900 with time and (B) estimated discharge and bromide concentration 

with distance for stream and inflow samples along the study reach, Silver Creek, 

Utah, April 2004 ...........................................................................................................................10

5. Box plots showing the range of trace-element concentration among synoptic 

inflow samples collected from Silver Creek, Utah, April 2004.............................................12

6. Variation of pH with distance along the study reach for stream-water and inflow 

samples collected along Silver Creek, Utah, April 2004.......................................................14

iii
iv

7. Variation of (A) sulfate and (B) zinc concentrations with distance along the study 

reach for stream-water and inflow samples collected along Silver Creek, Utah, 

April 2004......................................................................................................................................15

8. Variation of (A) cadmium with zinc concentration and (B) mole ratio of cadmium 

to zinc with distance along the study reach for stream-water and inflow samples 

collected along Silver Creek, Utah, April 2004.......................................................................16

9. (A) Variation of sulfate load with distance along the study reach and (B) change 

in sulfate load for individual stream segments, Silver Creek, Utah, April 2004 ................20

10. (A) Variation of aluminum load with distance along the study reach and (B) 

change in aluminum load for individual stream segments, Silver Creek, Utah, 

April 2004......................................................................................................................................21

11. (A) Variation of zinc load with distance along the study reach and (B) change in 

zinc load for individual stream segments, Silver Creek, Utah, April 2004. ........................22

12. Zinc load at common sampling sites from studies in 2002 and 2004, Silver Creek, 

Utah...............................................................................................................................................23

Tables

1. Details of tracer injections for three injection reaches along Silver Creek, Utah, 

April 2004........................................................................................................................................5

2. Bromide concentration of synoptic water samples and characteristics of the sites 

at which the samples were collected, Silver Creek, Utah, April 2004 ...............................25

3. Concentration of major ions in synoptic water samples collected along Silver 

Creek, Utah, April 2004...............................................................................................................28

4. Concentration of trace elements in synoptic water samples collected along 

Silver Creek, Utah, April 2004....................................................................................................31

5. Method detection limits and relative standard deviation of quality-assurance 

samples, Silver Creek, Utah, April 2004...................................................................................11

6. Median, minimum, and maximum pH value and concentration of selected 

consituents in groups of inflow samples collected along Silver Creek, Utah, 

April 2004......................................................................................................................................13

7. Summary of principal locations of mass loading for Silver Creek, Utah, April 2004 .......18
v

Conversion Factors, Datum, and Abbreviated Water-Quality 

Units

Multiply By To obtain

Length

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi)

Area

square kilometer (km2

) 247.1 acre

Volume

liter (L) 0.264 gallon (gal)

milliliter (mL) 0.000264 gallon (gal)

microliter (μL) 0.000000264 gallon (gal)

Flow rate

liter per second (L/s) 15.85 gallon per minute (gal/min) 

Mass flow

milligram per second (mg/s) 0.1905 pound avoirdupois per day (lb/day)

kilogram per day (kg/day) 2.205 pound avoirdupois per day (lb/day)

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

°F=(1.8×°C)+32.

Horizontal coordinate information is referenced to the North American Datum of 1927 (NAD 

27).

Chemical concentration and water temperature are reported only in metric units. Chemical 

concentration is reported in milligrams per liter (mg/L), micrograms per liter (μg/L), or millimoles per liter (mM/L). Milligrams per liter is a unit expressing the mass of solute per unit volume (liter) of water. For concentrations less than 7,000 milligrams per liter, the numerical value 

is about the same as for concentrations in parts per million. Specific conductance is reported in 

microsiemens per centimeter at 25 degrees Celsius (μS/cm).
vi
Principal Locations of Metal Loading from Flood-Plain 

Tailings, Lower Silver Creek, Utah, April 2004

By Briant A. Kimball, Robert L. Runkel, and Katherine Walton-Day

Abstract

Because of the historical deposition of mill tailings 

in flood plains, the process of determining total maximum 

daily loads for streams in an area like the Park City mining 

district of Utah is complicated. Understanding the locations 

of metal loading to Silver Creek and the relative importance 

of these locations is necessary to make science-based 

decisions. Application of tracer-injection and synopticsampling techniques provided a means to quantify and rank 

the many possible source areas. A mass-loading study was 

conducted along a 10,000-meter reach of Silver Creek, Utah, 

in April 2004. Mass-loading profiles based on spatially 

detailed discharge and chemical data indicated five principal 

locations of metal loading. These five locations contributed 

more than 60 percent of the cadmium and zinc loads to Silver 

Creek along the study reach and can be considered locations 

where remediation efforts could have the greatest effect upon 

improvement of water quality in Silver Creek.

Introduction

In heavily mined watersheds, numerous tailings and 

waste-rock piles may occur that can be sources of metals and 

acidity to streams. The challenge facing those interested in 

improving water quality is thus one of source determination: 

in a given watershed, what sources of water are most 

detrimental to stream-water quality and how do they compare? 

Source determination also is particularly important in the Total 

Maximum Daily Load (TMDL) process because individual 

sources must be identified, and their relation to the total load 

from all sources must be quantified. 

In response to the source-determination question, an 

approach has been developed within the U.S. Geological 

Survey (USGS) Toxic Substances Hydrology Program 

to quantify mass loading associated with various sources 

(Kimball and others, 2002). This approach combines the 

methods of tracer dilution to quantify discharge and synoptic 

sampling to provide spatially detailed chemical information. 

Given discharge and chemical data, profiles of mass loading 

illuminate the principal locations where sources contribute 

metals and acid to a stream. The purpose of this investigation 

was to identify the principal locations of metal mass loading 

to Silver Creek in Summit County, Utah (fig. 1), a tributary to 

the Weber River, to provide information for the Silver Creek 

TMDL process for the Utah Department of Environmental 

Quality, Division of Water Quality (UDEQ).

The mass-loading approach was employed by the USGS 

to quantify mass loading of metals to Silver Creek along a 

10,000-m study reach that is listed on Utah’s 303(d) list as 

being impacted by zinc and cadmium (Michael Baker Jr., Inc., 

2004; Utah Department of Administrative Services, 2005). A 

reconnaissance mass-loading study in the southern portion of 

lower Silver Creek identified substantial loading of metals to 

Silver Creek, but the analysis only quantified the net loading; 

it did not give details about the location of particular sources 

in this portion of lower Silver Creek (Kimball and others, 

2004). Almost all of these tailings occur in the flood plain of 

Silver Creek, and thus they are commonly called “flood-plain” 

tailings.

Purpose and Scope

The purpose of this report is to document the principal 

locations of metal mass loading to Silver Creek, Utah. This 

report (1) characterizes the chemistry of stream water and 

inflows along the Silver Creek study reach, (2) quantifies 

the metal loading along the study reach, and (3) identifies 

the principal locations where metal loading occurs. These 

results will facilitate science-based decisions about targets for 

remediation.

Description of the Study Area

This study addresses the reach of Silver Creek from 

the U.S. Highway 40 overpass to the Interstate 80 overpass, 

a reach of almost 10,000 m (fig. 1). Silver Creek originates 

upstream from Park City, Utah (to the southwest of the area 

in fig. 1), and flows into the Weber River near Wanship, Utah 

(to the northeast of the area in fig. 1). This has been called 

the southern portion of the lower Silver Creek site by UDEQ 

in their Innovative Assessment (Ann Tillia, Utah Department 

of Environmental Quality, written commun., 2005). USGS 
2 Principal Locations of Metal Loading from Flood-Plain Tailings, Lower Silver Creek, Utah, April 2004

EXPLANATION

Road

Reaches with similar stream chemistry

 Upstream

 Right branch of upstream section

 Upper meadow tailings

 Lower meadow tailings

 Downstream from waste-

 water treatment inflow

Stream site indicating distance

 (in meters, m) from injection

Inflow site indicating distance

 (in meters, m) from injection 1,601 m

Start of middle 

injection reach

1,452 m

End of upper

injection reach

(diversion)

Upper meadow 

tailings piles

Area where

stream is

dispersed

Wetland area

Interstate 80

U.S. Highway 40

Highway 248

U.S. Highway 40

Upstream

tailings Richardson Flat

tailings pond

0 m

Start of

upper

injection

reach at 

overpass

1,371 m

861 m

2,171 m

3,162 m

3,901 m

5,251 m

To Park City

1,965 m

525 m

1,843 m

625 m

672 m

1,309 m

2,118 m

3,371 m

4,800 m

7,259 m

End of middle 

injection reach 7,142 m

Start of lower 

injection reach

Approximate

Big 4 mill site

9,360 m

Irrigation

return flow

9,747 m

End of lower

injection reach

8,909 m

U.S. Geological 

Survey gaging station

10129900

8,881 m

Waste-water

treatment inflow

Area of Big 4

 and

lower meadow

8,886 m 8,497 m

5,624 m

6,322 m

7,687 m

7,571 m

2,757 m

8,862 m

111°27'

0 500

.5

METERS

MILE

1,000

0 1

2,048 m

Silver

Creek

Junction

Pivotal Promontory

access road

Silver Creek

111°30'

40°44'

40°41'

1,229 m

Salt Lake City

Weber River

Silver Creek

study area

U T A H

Great

Salt

Lake

4,403 m

6,045 m

4,403 m

6,045 m

Figure 1. Location of the study reach indicating upper, middle, and lower injection reaches, location of changes in stream-water 

chemistry (colors indicate classification by cluster analysis), and principal locations of tailings, Silver Creek, Utah, April 2004.
Introduction 3

discharge-gaging station 10129900, Silver Creek near Silver 

Creek Junction, Utah, is located near the end of the study 

reach and measures flow from a drainage area of 45 km2

. The 

flow measured at the gage includes discharge from a wastewater treatment plant (WWTP) located just upstream from the 

gage (fig. 1). 

Timing of the sampling was planned so that samples 

would reflect stream-water quality under snowmelt runoff 

conditions because Silver Creek can be ephemeral along this 

study reach during typical low-flow periods. Mean annual 

discharge at the gaging station is 82 L/s, based upon discharge 

records for 2002 through 2004, which were all years with 

drought conditions (Tibbetts and others, 2004; Wilkowske 

and others, 2003). Monthly mean discharge varies from a 

low of 44 L/s in September to a high of 206 L/s in March. 

April has a monthly mean discharge of 167 L/s at the stream 

gage; this value and that from March are a result of snowmelt 

runoff. Most of the discharge at the gage during low-flow 

months is from discharge of the WWTP. Upstream from the 

WWTP, which is most of the study reach, Silver Creek can be 

ephemeral. 

Diversions of Silver Creek required that the 10,000-m 

study reach be divided into three injection reaches for the 

study (fig. 1). The upper injection reach (from 0 to 1,452 m) 

contained a wetland area that started downstream from 525 m. 

Silver Creek discharges from the wetland into two branches 

that flow under Highway 248 through two separate culverts. 

The two branches converge again upstream from 1,371 m, 

allowing for an accounting of discharge at the end of the 

upper injection reach. For the stream sites between 525 m 

and 1,371 m, no discharge estimate was possible. The upper 

injection reach included two important locations for floodplain tailings. An area just downstream from the start of the 

study reach is locally referred to as the “flood-plain” tailings, 

but has been labeled “upstream tailings” in figure 1 (fig. 2A). 

At Richardson Flat, a tailings pond is separated from direct 

contact with Silver Creek by an earthen dam.

During recent periods of drought, discharge at 1,452 

m usually has been diverted down the valley in an irrigation 

ditch along the east side of the Silver Creek valley. For the 

purposes of this study, some of the water was allowed back 

into the natural channel of Silver Creek at 1,452 m to provide 

continuous discharge along the entire middle injection reach 

(1,601 to 7,259 m). Because the study occurred at the end 

of the snowmelt period in Silver Creek, this was a diversion 

into a channel that had not been dry for a substantial period 

of time. Thus, the diverted flow was not adsorbed by a dry 

alluvial channel. Much of the channel contained flow before 

the diversion, but continuous discharge in the natural channel 

was necessary to join all the ground-water inflows and to 

quantify loading from the ground-water discharge along the 

middle injection reach. In the meadow area, from 1,601 m 

to 7,142 m, two principal areas contain visible tailings piles; 

upper areas from 1,843 m to about 3,162 m; and a lower 

area from 5,251 m to 7,142 m. Tailings in both the upper and 

lower meadow areas are present in piles (mounds, berms, and 

hummocks) along the stream that could have been created in 

preparation for shipping to be reprocessed (Ann Tillia, Utah 

Department of Environmental Quality, written commun., 

2005). Vegetation around the tailings is very scarce; the 

mounds are mostly bare. A typical inflow from mounds of 

tailings in the upper meadow area is shown in figure 2B. 

Ground-water discharge from the lower meadow area is shown 

in figure 2C.

The lower injection reach (7,142 to 9,747 m) contained 

continuous discharge as a result of the ground-water discharge 

upstream in the middle injection reach. Tailings from the 

operation of the Old Big 4 mill, which was located near the 

present Pivotal Promontory access road, contribute metals to 

the lower tailings area. Additional tailings farther downstream 

also contribute metals (figs. 1 and 2D). This lower reach also 

receives discharge from the WWTP as well as return flow at 

9,360 m from the irrigation ditch that starts at 1,452 m in the 

upper injection reach. 

Details of the ore deposits in the Park City district have 

been discussed by Garmoe and Erickson (1968) and Bromfield 

(1989). Because the study reach is affected by tailings from 

the ore processing, the mineralogy of the ore deposits is the 

most important aspect of these reports. Sphalerite (ZnS) is the 

principal ore mineral contributing zinc. Cadmium commonly 

substitutes for zinc in sphalerite; thus, this mineral is the 

principal source of cadmium as well. Additionally, some of the 

ores occurred as skarn deposits, which are hosted in carbonate 

rocks. Carbonate minerals, especially rhodochrosite (MnCO3

), 

also occurred as gangue minerals in the intrusions (Rockwell 

and others, 1999). Thus, tailings from these ores should have 

abundant sphalerite and carbonate rhodochrosite.

Previous Work

A reconnaissance of this same study reach by Kimball 

and others (2004) included stream discharge and chemistry for 

four locations. These locations were upstream and downstream 

from Richardson Flat, and upstream and downstream from the 

WWTP. Loads of cadmium and zinc increased downstream 

between each of these four sampling locations. At the time 

of that study (Kimball and others, 2004), discharge from 

Silver Creek was completely diverted into an irrigation ditch, 

and there was no continuous flow in the natural channel. 

Numerous ground-water discharges from tailings in the 

meadow area were observed, but the amount of mass loading 

from the various inflows was not quantified. At the sampling 

site upstream from the WWTP, the ground-water discharge 

had combined to create continuous flow in the channel. 

Information from the study area has been compiled 

for a TMDL study (Michael Baker Jr., Inc., 2004). As 

with the USGS reconnaissance, however, there was little 

detail on sources within the meadow area. Another USGS 

study (Giddings and others, 2001) identified elevated metal 

concentrations in bed sediments of Silver Creek. The elevated 
4 Principal Locations of Metal Loading from Flood-Plain Tailings, Lower Silver Creek, Utah, April 2004

B

C D

A

Figure 2. Photographs of major sources of metal loading along the study reach, Silver Creek, Utah, April 2004. (A) Looking upstream 

toward injection point under the Highway 40 bridge and the “upstream” tailings; (B) Looking upstream while sampling an inflow draining 

from mounds of tailings in the upper meadow tailings area; (C) Looking upstream at the pond at the end of the lower meadow tailings 

area, upstream from Pivotal Promontory access road; and (D) Looking upstream at tailings in the flood plain downstream from historical 

Old Big 4 mill site.
Methods for Mass-Loading Approach 5

concentrations extended all the way from the Park City area to 

the mouth of Silver Creek.

Acknowledgments

This study was done in cooperation with the Utah 

Department of Environmental Quality, Division of Water 

Quality. Additional support was provided by the U.S. 

Geological Survey Toxic Substances Hydrology Program. 

Field assistance was provided by Andrew Burr, Jay Cederberg, 

Steven Gerner, James Mason, Judy Steiger, Ann Tillia, and 

John Whitehead. Logistical support and additional information 

were provided by John Whitehead and Ann Tillia of the Utah 

Department of Environmental Quality. Metal analyses were 

done at the University of Southern Mississippi under the 

direction of Alan Shiller; anion analyses were done by Judy 

Steiger at the U.S. Geological Survey Utah Water Science 

Center.

Methods for Mass-Loading Approach

A mass-loading approach to identify sources of metals 

combines several methods. Details of these methods are 

reported elsewhere (Kimball and others, 2002; Kimball and 

others, 2004; Kimball and others, 2006b; Kimball and others, 

2006a), but some aspects are repeated here to help understand 

the results for Silver Creek. Data collection for the approach 

is based on field methods of tracer dilution (Kilpatrick and 

Cobb, 1985) and synoptic sampling (Bencala and McKnight, 

1987). Data analysis is based on methods of calculating 

loads to obtain detailed longitudinal profiles of mass loading 

(Kimball and others, 2002; Kimball and others, 2003). Also, 

multivariate sample-classification methods help to interpret the 

detailed chemical results. 

Tracer Injection and Synoptic Sampling

The mass-loading study began with a careful evaluation 

of inflows along the study reach, which was accomplished 

by walking the entire study reach (fig. 1). Before flow was 

diverted into the middle injection reach, ground-water inflows 

were evident, and their cumulative effect created some 

perennial discharge by the end of the middle injection reach. 

Stream sites for synoptic sampling were chosen upstream 

and downstream from the inflows to allow mass-balance 

calculations. Additional stream sites were located along 

the study reach at regular intervals to check for dispersed, 

subsurface inflow to the stream. Sampling sites for the 

synoptic study are referenced by the measured distance along 

the study reach in a downstream direction, with the injection 

site assigned a distance of 0 m. Inflows are referred to as 

left and right bank with an orientation looking downstream. 

Reference to a stream segment means the section of the study 

reach between two consecutive stream sites, and is referenced 

by both the upstream and downstream distances, for example 

the segment 1,601–1,843 m. 

A continuously injected chemical tracer provides a way 

to measure discharge that includes the hyporheic flow of 

the stream because it follows the water as it moves in and 

out of the streambed. Under ideal conditions, tracer-dilution 

techniques allow the detection of increases in discharge 

of only a few percent. Once the tracer reaches a steady 

concentration at each point along the stream, called the plateau 

condition, discharge can be calculated at any stream point 

from the concentration of the tracer at that point. This typical 

application of a tracer-injection study was adequate for the 

upper and lower injection reaches, but for the middle injection 

reach the approach was modified.

Sodium bromide was selected for the injection solution 

because of the high pH of the stream. No geologic sources of 

bromide were suspected in the watershed (Nichols and Bryant, 

1990). In the analysis of this experiment, bromide is assumed 

to be a conservative tracer. No adverse effects on organisms 

were observed from the injection of the tracer solution. Details 

of the three tracer injections are provided in table 1, and the 

system of pumps and controls is detailed in Kimball and others 

(2004).

The background concentration of the tracer was much 

lower than the concentration of injected tracer in the stream 

and was mostly uniform. With these uniform background 

Table 1. Details of tracer injections for three injection reaches along Silver Creek, Utah, April 2004.

[L/s, liters per second; mg/L, milligrams per liter]

Injection 

reach

Injection 

start

Synoptic 

start

Synoptic 

end

Injection 

end Injection 

rate 

(L/s)

Tracerinjectate 

concentration

(mg/L 

as bromide)

Background 

bromide 

concentration 

(mg/L) Date Time Date Time Date Time Date Time

Upper 4/14/2004 12:00 4/15/2004 9:07 4/15/2004 13:25 4/15/2004 11:00 0.00123 159,600 0.24

Middle 4/8/2004 9:00 4/9/2004 8:55 4/9/2004 14:12 4/9/2004 15:00 .00100 162,800 .31

Lower 4/5/2004 15:27 4/6/2004 9:34 4/6/2004 14:00 4/6/2004 15:50 .00251 160,300 .31
6 Principal Locations of Metal Loading from Flood-Plain Tailings, Lower Silver Creek, Utah, April 2004

concentrations, stream discharge at any location downstream 

from the injection is given by:

(1)

where:

QD is the stream discharge at the downstream site, 

in L/s,

QINJ is the injection rate (table 1), in L/s,

CINJ is the injectate concentration, in mg/L,

CD is the tracer concentration at a downstream site, 

in mg/L, and

CB is the naturally occurring tracer concentration, in 

mg/L.

The amount of tracer dilution between two consecutive 

stream sites indicates the total inflow from surface and 

ground water for that segment of the study reach. Tracer 

dilution accounts for visible inflows, such as tributaries and 

springs, as well as dispersed, subsurface inflow. No separate 

measurement was made of tributary inflow to be able to divide 

the total inflow volume between surface- and ground-water 

components for a given stream segment.

Synoptic samples were collected at numerous stream 

and inflow locations after the bromide concentration reached 

a steady-state plateau. Sampled inflows were mostly small 

springs and some irrigation return flows; only one welldefined tributary occurred at 9,562 m. A complete listing of 

sampling locations, sample information, and the chemical 

data are provided in tables 2, 3, and 4 (located at back of 

report). Samples were collected in 1.8-L HPDE bottles usually 

by submersing the neck of each bottle into the water near 

the center of flow. Samples were transported to a central 

processing area where 125-mL aliquots were prepared 

for cation and anion analyses. Onsite processing included 

filtration and pH measurement. Filtration was completed 

with in-line capsule disk filters with an effective pore size 

of 0.45-μm (FA samples). Some total-recoverable samples 

(RA) were collected to evaluate the presence of colloidal 

concentrations of metals. The colloidal concentration 

was calculated as the difference between the RA and FA 

concentration for those samples that included both. Both FA 

and RA aliquots for cation analysis were acidified to a pH 

of less than 2.0 with ultrapure nitric acid. Total recoverable 

and dissolved cation concentrations were determined from 

unfiltered and filtered samples, respectively, by using 

inductively coupled argon plasma-mass spectrometry. Cation 

concentrations are reported for aluminum, arsenic, barium, 

calcium, cadmium, cobalt, chromium, copper, iron, potassium, 

magnesium, manganese, molybdenum, sodium, nickel, lead, 

silica (as silicon), silver, strontium, uranium, vanadium, and 

zinc. Dissolved anion concentrations were determined from 

filtered, unacidified samples by ion chromatography. Anion 

concentrations are reported for chloride, bromide, and sulfate. 

Q Q C

C C D

INJ INJ

D B

= −

Alkalinity (as calcium carbonate) was determined by titration 

from filtered, unacidified samples.

Load Calculation

Three specific load calculations are used to quantify the 

sources of loading to Silver Creek. First, the tracer injection 

provides estimated discharge ( Q) and synoptic sampling 

provides constituent concentrations (C), which are combined 

to determine sampled instream load:

M C A A = QA( . )0 0864 (2)

where:

MA is the constituent load, or mass flux, at location 

A, in kg/day, 

CA is the concentration of the selected constituent at 

location A, in mg/L,

QA is the discharge at location A, in L/s, and

 0.0864 is the conversion factor from mg/s to kg/

day. 

Sampled instream load for stream sites was calculated 

from the filtered concentration (FA sample) of the constituent. 

The longitudinal profile of sampled instream load is the basic 

result from the mass-loading study.

The second load calculation determines the net change 

in mass load in one stream segment, and is used to determine 

if the load of a given constituent increases or decreases in the 

given segment. For the change in load for the segment starting 

at location A and ending at location B, we calculate:

∆MB –A = MB – MA (3)

where:

DMB–A is the change in sampled instream load from 

locations A to B, in kg/day,

MB is the constituent load at location B, in kg/day, 

and

MA is defined in equation 2.

Gains in constituent load (DMB–A is greater than zero) 

imply that there is a source that contributes to the stream 

between the two stream sites. Instream load also can decrease 

within a stream segment (DMB–A is less than zero), meaning 

that there was a net loss of the constituent from physical, 

chemical, or biological processes. Summing all the increases 

in load between sampling sites along the study reach (positive 

values of DMB–A) leads to the cumulative instream load. At 

the end of the study reach, the cumulative instream load is the 

best estimate of the total load added to the stream but is likely 

a minimum estimate because it only measures the net loading 
Methods for Mass-Loading Approach 7

for segments and does not account for loss resulting from 

reaction.

For those segments that include a sampled inflow, a third 

load calculation is possible. If stream sites A and B surround 

an inflow sample, location I:

�M C I I = − Q Q B A ( )( . )0 0864 (4)

where:

DMI is the load attributed to the inflow, I, in kg/day,

CI is the inflow concentration, in mg/L,

QB is the discharge at site B, in L/s, and

QA and 0.0864 are defined in equation 2.

Summing the inflow loads along the study reach produces 

a longitudinal profile of the cumulative inflow load. This sum 

can be compared to the cumulative instream load to indicate 

how well the sampled inflows account for the load measured 

in the stream. The cumulative instream and cumulative inflow 

profiles would be nearly equal if the sampled inflows were 

completely representative of the constituent concentration for 

all the water entering the stream, but that is rarely the case. 

Ground-water inflow into streams affected by mine drainage 

often has higher concentrations of metals than surfacewater inflows into the same stream segment. This causes the 

cumulative instream load to be greater than the cumulative 

inflow load and can indicate important areas of unsampled 

inflow load, which is defined as:

DMU =DMB–A –DMI (5)

where:

DMU is the unsampled inflow load, in kg/day, and

DMB–A and DMI are defined in equations 3 and 4.

Unsampled inflow can be calculated for individual stream 

segments even if the segment does not include a sampled 

inflow or for the entire study reach by comparing the 

cumulative instream and inflow loads. If the value is negative 

for the entire study reach, however, it can still be positive for 

some individual stream segments. Note that DMB–A includes 

all sources of loading within a stream segment and, in most 

cases, does not distinguish the quantity added by an individual 

source. 

Because there is measurement error inherent in discharge 

estimates, chemical analysis, and sampling, a load error 

equation is used to constrain the changes of sampled instream 

load. The load error is calculated from an equation that 

accounts for these potential sources of error (McKinnon, 

2002):

Load error = + ( ) Q C C Q ( . ) A A A A

2 2 2 2 � � 0 0864 (6)

where:

DCA is the precision of chemical analysis,

DQA is the precision of discharge calculation, and

QA, CA and 0.0864 are defined in equation 2.

The value of DCA is calculated in a manner analogous to 

that used by Friedman and Erdman (1982) for single operator 

precision. The coefficient of variation (CV), representing 

precision, and the mean concentration are calculated for 

repeated analysis of a constituent in a set of standard reference 

samples spanning a range of concentrations. Values for CV are 

regressed as a power function of the mean concentrations to 

obtain an equation expressing analytical precision, DCA, as a 

function of concentration:

�C a A A C b = ( ) (7)

where:

DCA is precision for the chemical measurement at site 

A, in percent,

a is the coefficient from regression,

CA is the concentration of the constituent at site A, and

b is the exponent from regression.

The value of DQA is based on the CV for the plateau 

tracer concentration at the transport sites during the period of 

synoptic sampling. For example, for the upper injection reach 

(fig. 3A), the mean bromide concentrations at transport sites 

T1 and T3 during synoptic sampling were 4.23 mg/L and 

1.74 mg/L, respectively (site T2 was not located on the main 

channel, but on the returning ditch, an inflow). The value of 

CV for site T1 was 2.5 percent and for site T3 was 9.6 percent. 

Similar to the procedure for analytical precision, the values of 

CV for each mean are used to develop a linear regression for 

DQA:

�Q mC b A A

T = + (8)

where:

DQA is the discharge error at site A,

m is the slope from linear regression,

CT

A is the tracer concentration at site A, and

b is the intercept from linear regression.

Both DCA and DQA give the percentage of CA and QA

to be substituted into equation 6 to calculate load error. The 

load error is compared to the change in load to the next site, 

DMB–A. If the absolute value of DMB–A is greater than the load 

error, then there has been a measurable and significant change 
8 Principal Locations of Metal Loading from Flood-Plain Tailings, Lower Silver Creek, Utah, April 2004

Figure 3. Variation of bromide concentration at transport sites with time for (A) upper, (B) middle, and (C) lower injection reaches, 

Silver Creek, Utah, April 2004.

Heading 1 3

12:00 16:00 20:00 00:00 04:00 08:00 12:00 16:00

0

2

4

6

8

10

12

06:00 12:00 18:00 00:00 06:00 12:00 18:00

0

1

2

3

4

10:00 12:00 14:00 16:00 18:00 20:00 22:00 00:00 02:00 04:00 06:00 08:00 10:00 12:00 14:00

0

1

2

3

4

5

6

 T1

 T2

 T3

Period of synoptic

sampling

C

DATE AND TIME, IN HOURS

4/5/2004 4/6/2004

4/8/2004 4/9/2004

 T1

 T2

 T3

Period of synoptic

sampling

B

4/15/2004

 T1

 T2

 T3

BROMIDE CONCENTRATION, IN MILLIGRAMS PER LITER

A

Period of synoptic

sampling

4/14/2004
Discharge from Tracer Dilution 9

in load. Only the values of DMB–A that are greater than the 

load error are included in the longitudinal profiles of sampled 

instream load and the cumulative instream load.

Sample Classification

An important objective of synoptic sampling is to 

recognize patterns or chemical characteristics among samples 

that can indicate the sources of mine drainage. Water that 

interacts with distinct mineral assemblages may exhibit 

characteristic chemical signatures that can provide distinctions 

among the inflow samples. Thus, groups of inflow samples 

are identified by their similarities. In this study, distinctions 

among inflow groups lead to understanding differences in 

drainage from the various areas where tailings occur. Groups 

of stream-water samples indicate where major changes occur 

in surface-water chemistry. Sample classification was done 

separately for inflow and for stream-water samples.

A cluster analysis method called partitioning around 

medoids was used to evaluate distinctions among the inflow 

and stream-water samples (Kaufman and Rousseeuw, 1990). 

For both stream-water and inflow samples, the method uses 

the Euclidian distance between samples in multi-dimensional 

space to determine clusters or groups of samples with samples 

that are similar, and yet groups that are the most distinguished 

from each other. To emphasize the linear relations among 

variables, the chemical concentration of each constituent, is 

expressed in millimoles per liter. These values are converted 

to standardized variables in the analysis. Only filtered 

concentrations were used as input to the analysis. 

Discharge from Tracer Dilution

Understanding the effects of flood-plain tailings on mass 

loading to Silver Creek is based on three critical lines of 

evidence. First is the estimation of discharge from the tracer 

dilution, second is the pattern of chemical variation of inflow 

and instream concentrations, and third is the longitudinal 

pattern of mass loading that comes from a combination of the 

synoptic discharge and chemical data.

To estimate discharge from tracer dilution, a concentrated 

sodium bromide solution was slowly pumped into the 

stream at the upstream end of each injection reach. Details 

of the time, injection rate, and tracer concentration of the 

injectate solution for each injection reach are presented 

in table 1. During the periods of synoptic sampling, the 

tracer concentration in the middle (fig. 3B) and lower (fig. 

3C) reaches appeared to attain a steady-state plateau at 

each transport site. During synoptic sampling for the upper 

injection reach (fig. 3A), however, a plateau occurred at site 

T1, but tracer concentrations at sites T2 and T3 appeared to 

be increasing. Thus, discharge estimates downstream from 

525 m for the upper injection reach were not calculated. 

For the middle and lower injection reaches, however, where 

concentrations vary with downstream distance, but not with 

time, values of bromide concentration for each synoptic 

stream site can be used to estimate a discharge value by using 

equation 1. Smoothed bromide concentrations, using the 

method of Velleman and Hoagland (1981), were used in the 

discharge calculations, and the smoothed concentrations of 

the bromide tracer and estimated discharge at all of the stream 

sites are listed in table 2 (located at back of report).

Bromide concentrations of inflow samples were variable 

(fig. 4B). The median bromide concentration among inflows 

(excluding those inflows that directly drained roads) was 0.3 

mg/L (fig. 4B), which is a likely background concentration for 

this study reach. Twelve samples had a bromide concentration 

of greater than 0.5 mg/L (fig. 4B), and those samples most 

likely had some portion of stream water in them. Most of these 

samples were collected in the middle injection reach where the 

diversion of water could have caused some back mixing with 

inflows. Because higher bromide concentrations among inflow 

samples were likely the result of injected bromide, and not 

the result of natural sources of bromide, the instream bromide 

concentrations should remain acceptable for calculating 

discharge with equation 1.

Discharge estimates must be viewed in the context 

of variation that occurred during the 10-day period of the 

injections (fig. 4A). Hourly-scale variation in the gagingstation record resulted from variable discharge of the WWTP, 

and this variation did not occur upstream from the WWTP. 

Daily scale variation was a result of diel variations from 

snowmelt. Two periods of rain occurred and discharge peaked 

at the gaging station at about 0:00 hours on April 8 and 0:00 

hours on April 9. The period of synoptic sampling for each 

injection is indicated by vertical lines, and discharge at the 

gage varied from an average of 110 L/s during the lower 

injection, to 209 L/s during the middle injection, to 67 L/s 

during the upper injection. 

Discharge at the end of the middle injection reach (fig. 

4B), was substantially greater than at the beginning of the 

lower injection reach. In a temporal context (fig. 4A), the 

difference is explained by the storms that occurred between 

the two injections. The base discharge at the gaging station 

was 123 L/s higher during the middle than during the lower 

injection and mostly accounts for the difference of 142 L/s 

(fig. 4A) between the two injection reaches. The comparable 

values of discharge at the end of the upper injection reach on 

April 14 and the beginning of the middle reach on April 9 

should differ by much more than they do, because discharge 

at the end of the upper injection reach on April 9 should have 

been greater after the storms. Not all the discharge from the 

upper injection reach, however, was diverted to the natural 

channel for the middle injection reach, and the amount that 

was diverted was nearly equal to the discharge at the beginning 

of the middle injection reach on April 9. Thus, the temporal 

variations over the 10-day period can explain the discharges 

illustrated in figure 4B.
10 Principal Locations of Metal Loading from Flood-Plain Tailings, Lower Silver Creek, Utah, April 2004

Figure 4. Variation of (A) discharge measured at U.S. Geological Survey streamflow-gaging station 10129900 with time and (B) 

estimated discharge and bromide concentration with distance for stream and inflow samples along the study reach, Silver Creek, Utah, 

April 2004.

0 2,000 4,000 6,000 8,000 10,000

0

20

40

60

80

100

120

140

160

180

200

0

1

2

3

4

5

6

7

8 Discharge, upper

 Discharge, middle

 Discharge, lower

 Bromide, upper

 Bromide, middle

 Bromide, lower

 Bromide, inflows

DISTANCE ALONG STUDY REACH, IN METERS

DISCHARGE, IN LITERS PER SECOND

BROMIDE CONCENTRATION, 

IN MILLIGRAMS PER LITER

Ditch from

Richardson Flat

Start of middle reach

Start of lower reach

Waste-water

treatment plant

inflow

Irrigation return

4/4/2004 4/6/2004 4/8/2004 4/10/2004 4/12/2004 4/14/2004 4/16/2004

0

100

200

300

400

B

Upper injection

Middle injection

DISCHARGE, IN LITERS PER SECOND

Lower injection

A

U.S. Geological Survey

streamflow gaging station 10129900
Chemical Variation of Synoptic Samples 11

Chemical Variation of Synoptic 

Samples

The discharge profiles of each injection reach are 

combined with an equally detailed profile of stream and 

inflow chemistry. For this 10,000-m study reach, 52 stream 

and 46 inflow sites were sampled to provide the desired 

characterization (table 2). Results of chemical determinations 

are listed in table 3 for major ions and table 4 for trace 

elements (both tables located at back of report). All samples 

were evaluated for charge balance and all but two samples had 

a balance less than 5.2 percent; the median balance was 1.97 

percent.

New spectroscopic technology, inductively coupled 

argon plasma/mass spectrometry, (ICP-MS), makes the 

determination of low concentrations of metals possible. 

Method detection limits for the analyses of the synoptic 

samples are listed in table 5; many detection limits were 

less than one part per billion. Precision for each element 

was determined by a modification of the method for single 

operator precision (Friedman and Erdmann, 1982). Statistics 

for calculating single operator precision were developed 

by running certified standards and field standard reference 

samples at regular intervals throughout the chemical analysis. 

By calculating the CV for a given concentration from these 

reference standards, power function equations for CV as a 

function of concentration were developed; coefficients and 

exponents for these equations are listed in table 5, and, as 

described in the “Methods” section, are used in the load error 

calculation to determine the DCA term in equation 6.

Inflow Samples

Metal concentrations measured for inflow samples span 

nine orders of magnitude, and a comparison using box plots 

(Velleman and Hoaglin, 1981) demonstrates this range (fig. 5). 

Such a large range of concentration suggests that the inflows 

sampled in this study most likely represent the possible range 

of inflow chemistry affecting Silver Creek in the study reach. 

A substantial percentage of the samples had cadmium, iron, 

manganese, strontium, and zinc concentrations that were 

greater than 100 μg/L. Zinc concentration in samples from 4 

inflows exceeded 100,000 μg/L, and one of these exceeded 

1,000,000 μg/L (fig. 5; table 4). These 

high concentrations indicate the potential 

importance of these flood-plain tailings as 

sources of metals to Silver Creek.

Inflow samples have been classified 

using cluster analysis into four groups on 

the basis of their chemical composition. 

Distinctions among the groups are evident 

from variations in pH and concentrations of 

selected constituents (table 6). The groups 

have been arranged in an order of decreasing 

pH and increasing concentration (with the 

exception of alkalinity), and this order could 

represent the extent of weathering of floodplain tailings or weathering of tailings having 

variable content of sphalerite and other 

metal-rich minerals such as rhodochrosite. 

None of the inflow samples can be considered 

totally unaffected by interaction with tailings 

material, but the groups may represent the 

extent of interaction or else the effect of 

differing mineralogy in the tailings material. 

Inflow samples that have the highest values of 

pH (least and moderately affected groups) also 

have the lowest concentrations of calcium, 

sulfate, and zinc, but the highest concentration 

of alkalinity. On the other hand, samples with 

the lowest pH have the highest concentrations 

of calcium, sulfate, and zinc (substantially 

affected and most affected groups).

Spatially, general distinctions exist 

among the groups of inflow samples. Inflows 

most affected by tailings occurred at the 

Table 5. Method detection limits and relative standard deviation of qualityassurance samples, Silver Creek, Utah, April 2004.

[MDL, method detection limit]

Constituent

MDL, 

in micrograms 

per liter

Coefficient of variation

Coefficient Exponent

Calcium 416 7.7586 -.2861

Magnesium 101 2.4179 -.3756

Sodium 302 3.7271 -.2209

Potassium 36 2.2376 .1502

Alkalinity as CaCO3 500

Sulfate 1,760 6.6228 -.3185

Chloride 480 3.7271 -.2209

Bromide 80 5.7087 -.3406

Silica, as Si 309 3.0626 .0624

Aluminum .2 1.6461 -.4146

Arsenic .01 3.6077 -.176

Barium .1 1.2463 -.1304

Cadmium .09 .6576 -.3452

Cobalt .01 .1594 -.57

Chromium .05 .8397 -.305

Copper .04 3.7668 .0892

Iron .3 1.3058 -.2804

Lead .01 .7153 -.1152

Lithium .5 1.0295 -.3813

Manganese 5 1.249 -.0496

Molybdenum .04 .8158 -.2531

Nickel .37 1.3722 -.4094

Silver .01 3.2254 -.2851

Strontium 2 11.556 .0854

Uranium .003 1.0411 -.0962

Vanadium .01 .08742 -.2047

Zinc 22 .8362 -.7002
12 Principal Locations of Metal Loading from Flood-Plain Tailings, Lower Silver Creek, Utah, April 2004 Aluminum Arsenic Barium Cadmium Cobalt Chromium Copper Iron Lead Manganese Molybdenum Nickel Silver Strontium Uranium

Vanadium

Zinc

0.01

0.1

1

10

100

1,000

10,000

100,000

1,000,000

2,000,000

FILTERED CONCENTRATION, IN MICROGRAMS PER LITER

EXPLANATION

Whiskers 5th, 95th

 percentiles

Mean

Box 25th, 75th

 percentiles

Maximum,

 minimum

Figure 5. Box plots showing the range of trace-element concentration among synoptic inflow samples collected from 

Silver Creek, Utah, April 2004.
Chemical Variation of Synoptic Samples 13

beginning and near the end of the middle injection reach 

(fig. 6, orange triangles at 1,965 m and 5,928 m). Both 

these inflows originated directly from tailings piles (table 

2). Moderately affected inflows (light blue triangles) mostly 

occurred from the beginning of the study reach (0 m) to near 

4,403 m. Substantially affected inflows (yellow triangles) 

mostly occurred from 5,251 m to 8,497 m. In general, this 

group of substantially affected inflows not only had lower pH 

than the least and moderately affected groups, but also had 

higher concentrations of sulfate and zinc (fig. 7A and B).

If the mining wastes were derived from ore deposits that 

had the same age of mineralization, the sphalerite might have 

a uniform ratio of cadmium to zinc. In a plot of cadmium with 

zinc, a constant ratio is represented by a line of unit slope (fig. 

8A). Not all samples plot along a line of unit slope (fig. 8A). 

Samples from the least and the moderately affected inflows 

had the most variable cadmium to zinc ratio, and samples from 

the substantially and most-affected inflows had a relatively 

constant ratio. This corresponds to a spatial pattern of higher 

ratios occurring among inflow samples between 2,000 and 

4,800 m (fig. 8B), or the area of the upper meadow tailings 

piles (fig. 1). Stream-water samples from this same area and 

also downstream to the end of the study reach generally had 

the same ratio and plot along the line of unit slope (fig. 8A). 

This result indicates that zinc and cadmium in the middle and 

lower injection reaches were mostly obtained from the tailings 

piles in those areas rather than from 

upstream sources. This is consistent 

with the substantial increases in zinc 

concentration among samples collected 

downstream from 2,000 m (fig. 7B) and 

has implications for remediation.

Stream Samples

Distinctions that occur among 

groups of stream-water samples have a 

different implication than distinctions 

among groups of inflow samples. As 

noted, distinctions among inflow sample 

groups could result from the degree 

of interaction with flood-plain tailings 

or the variable chemical character of 

tailings, both possibilities reflecting 

catchment sources of zinc. Distinctions 

among stream-water groups along the 

study reach in Silver Creek, however, 

represent changes in stream-water 

chemistry in response to inflows from 

the various sources. Consequently, 

the resulting classification of streamwater samples into groups represents 

a sequence of changes along the study 

reach. The locations of different groups 

are indicated in figure 1.

Sulfate and zinc concentrations 

illustrate the pattern of change for stream-water samples 

collected along the study reach (diamond symbols for streamwater samples; fig. 7A and B). From upstream to downstream, 

five groups were distinguished by cluster analysis and are 

designated as A-E.

•	 Group A (dark blue diamonds; 0 to 1,843 m) – Sulfate 

concentration at the beginning of the study reach was 

consistently near a median concentration of 294 mg/L. 

Zinc concentration progressively increased along the 

upper injection reach from 1,300 to almost 1,700 μg/L 

at 1,452 m. The increase could indicate a contribution 

from the “upstream” tailings (fig. 1), but the median 

zinc concentration of 1,590 μg/L was relatively low 

compared to concentrations downstream. 

•	 Group B (light blue diamonds; 861 m to 1,309 m) 

– The chemical character of samples from the right 

branch of the upper injection reach (stream-water 

samples collected at 861 m, 1,229 m, and 1,309 

m) differed from that of the main channel, with a 

slightly higher sulfate concentration, but a lower zinc 

concentration. The difference in chemistry indicates 

that ground water may flow into the right branch 

after the stream splits, but it is of note that metal 

concentrations are lower as a result.

Table 6. Median, minimum, and maximum pH value and concentration of selected 

consituents in groups of inflow samples collected along Silver Creek, Utah, April 2004. 

Groups are labeled by the degree to which they are affected by interaction with mining 

wastes. 

[mg/L, milligrams per liter; LD, less than detection limit; μg/L, micrograms per liter]

Constituent Group Number of 

samples Median Minimum Maximum

pH, in 

standard 

units

Least 3 7.92 7.64 8.16

Moderate 28 7.79 6.94 8.24

Substantial 12 7.37 5.98 7.57

Most 2 3.75 3.36 4.13

Calcium, in 

mg/L

Least 3 67.4 44.1 107

Moderate 28 220 52.9 463

Substantial 12 388 271 537

Most 2 458 436 479

Alkalinity as 

CaCO3

, 

in mg/L

Least 3 161 125 230

Moderate 28 150 33.6 279

Substantial 12 103 24.9 177

Most 2 LD LD LD

Sulfate, in 

mg/L

Least 3 51.5 9.4 107

Moderate 28 343 29.0 761

Substantial 12 1,083 667 3,250

Most 2 3,595 3,510 3,680

Zinc, in μg/L Least 3 178 25.6 657

Moderate 28 3,380 12.8 25,500

Substantial 12 37,443 8,380 1,070,000

Most 2 200,838 132,000 270,000
14 Principal Locations of Metal Loading from Flood-Plain Tailings, Lower Silver Creek, Utah, April 2004

 Stream, upstream from upper meadow tailings

 Stream, east branch of upper injection reach

 Stream, area near upper meadow tailings

 Stream, area including lower meadow tailings

 Stream, downstream from waste-water treatment

 Inflow, least affected by tailings

 Inflow, moderately affected by tailings

 Inflow, substantially affected by tailings

 Inflow, most affected by tailings

0 2,000 4,000 6,000 8,000 10,000

3.00

4.00

5.00

6.00

7.25

7.50

7.75

8.00

8.25

8.50

Stream gathered in channel

pH, IN STANDARDS UNITS

DISTANCE ALONG STUDY REACH, IN METERS

Ditch from Richardson Flat

Start of middle reach

Start of lower reach

Waste-water treatment plant inflow

Irrigation return

Figure 6. Variation of pH with distance along the study reach for stream-water and inflow samples collected along Silver Creek, Utah, 

April 2004. 

•	 Group D (orange diamonds; 5,251 m to 8,862 

m) – Concentrations of sulfate and zinc increased 

substantially a second time from the influence of 

the lower meadow tailings piles (fig. 7). Increases 

in both sulfate and zinc concentration occurred at 

the end of the middle injection reach, and again at 

the start of the lower injection reach. Particularly for 

zinc concentration, the increases were substantial 

and reflect the effect of the tailings, both in the lower 

meadow area (about 5,000 m to 7,142 m) and the Old 

•	 Group C (yellow diamonds; 2,171 m to 4,800 m) – 

Downstream from the point where water was diverted 

to the middle injection reach at 1,452 m, the first two 

stream-water samples (1,601 m and 1,843 m) were 

similar to the upstream stream-water samples (group 

A). However, there was a distinct change at 2,171 m 

that reflects the influence of the upper meadow tailings 

piles (fig. 1). Inflows from the upper meadow tailings 

piles caused substantial increases in both sulfate and 

zinc concentrations. Median concentrations between 

2,174 m and 4,800 m increased to 332 mg/L sulfate 

and 3,730 μg/L zinc (fig. 7A and B).

Big 4 mill area (7,142 m to 8,909 m). The mole ratio of 

the stream water for cadmium to zinc varies as a result 

of inflows in both these locations; first a decrease 
Chemical Variation of Synoptic Samples 15

 Stream, upstream from upper meadow tailings

 Stream, east branch of upper injection reach

 Stream, area near upper meadow tailings

 Stream, area including lower meadow tailings

 Stream, downstream from waste-water treatment

 Inflow, least affected by tailings

 Inflow, moderately affected by tailings

 Inflow, substantially affected by tailings

 Inflow, most affected by tailings

0 2,000 4,000 6,000 8,000 10,000

0

2,000

4,000

6,000

8,000

10,000

100,000

1,000,000

2,000,000

0 2,000 4,000 6,000 8,000 10,000

0

200

400

600

800

1,000

2,000

3,000

4,000

B

Stream gathered in channel

ZINC CONCENTRATION, IN MICROGRAMS PER LITER

DISTANCE ALONG STUDY REACH, IN METERS

Ditch from Richardson Flat

Start of middle reach

Start of lower reach

Irrigation return

SULFATE CONCENTRATION, IN MILLIGRAMS PER LITER

Ditch from Richardson Flat

Start of middle reach

Stream gathered in channel

Start of lower reach

Waste-water treament plant inflow

Irrigation return

A

Waste-water treament plant inflow

Chronic toxicity standard (Utah Department of Administrative Services (2005))

Figure 7. Variation of (A) sulfate and (B) zinc concentrations with distance along the study reach for stream-water and inflow samples 

collected along Silver Creek Utah, April 2004.
16 Principal Locations of Metal Loading from Flood-Plain Tailings, Lower Silver Creek, Utah, April 2004

0 2,000 4,000 6,000 8,000 10,000

0.000

0.001

0.002

0.003

0.004

0.005

0.006

0.007

0.008

DISTANCE ALONG STUDY REACH, IN METERS

Ditch from Richardson Flat

Start of middle reach

Start of lower reach

Waste-water treatment plant inflow

Irrigation return

10 -1 10 010 110 210 32x10 3

10 -4

10 -3

10 -2

10 -1

10 0

3x10 0

 Stream, upstream from upper meadow tailings

 Stream, east branch of upper injection reach

 Stream, area near upper meadow tailings

 Stream, area including lower meadow tailings

 Stream, downstream from waste-water treatment

 Inflow, least affected by tailings

 Inflow, moderately affected by tailings

 Inflow, substantially affected by tailings

 Inflow, most affected by tailings

B

CADMIUM CONCENTRATION, IN MILLIMOLES PER LITER

ZINC CONCENTRATION, IN MILLIMOLES PER LITER

A

Line of 

unit slope

MOLE RATIO OF CADMIUM TO ZINC

Figure 8. Variation of (A) cadmium with zinc concentration and (B) mole ratio of cadmium to zinc with distance along the study reach 

for stream-water and inflow samples collected along Silver Creek, Utah, April 2004.
Principal Locations of Mass Loading 17

occurred in the ratio from 5,251 m through 6,322 m, 

and then a steady ratio occurred near 7,571 m (fig. 8). 

•	 Group E (red diamonds; 8,909 m to 9,747 m) 

– Compared to the upstream group, almost all 

concentrations were lower as a result of dilution 

by the inflow of the WWTP (fig. 7), which entered 

Silver Creek at 8,881 m. Further dilution occurred 

downstream from the irrigation return flow at 9,360 m.

As described, the mole ratio of cadmium to zinc in 

stream-water samples indicates the influence of inflows from 

the tailings piles in the upper and the lower meadow areas (fig. 

8B). Waters from group A (dark blue diamonds) had a ratio 

near 0.0012, but at 2,171 m, the ratio increased to a nearly 

constant value of 0.0033 in response to high ratios of inflow 

waters. At 5,251 m, the instream ratio began to decrease in 

response to lower ratios of inflows from the lower meadow 

tailings piles, as noted above. In the lower injection reach, 

downstream from 7,142 m, the instream cadmium to zinc 

ratios in the stream-water samples were nearly constant. The 

initial change at 2,171 m and the subsequently constant ratio 

suggest the effect of tailings piles in the upper meadow area as 

a source of these metals. 

Concentrations of cadmium and zinc in stream-water of 

Silver Creek exceeded chronic aquatic-life standards (Utah 

Department of Administrative Services, 2005). All the streamwater samples exceeded the hardness-based chronic toxicity 

level for zinc (fig. 7B). For cadmium, water samples collected 

from all stream sites downstream from 1,601 m exceeded 

the hardness-based chronic toxicity standard. All instream 

concentrations of copper, lead, and nickel were less than the 

calculated hardness-based chronic toxicity standards.

Ten locations from the lower injection reach included 

analysis of both the filtered and unfiltered samples (table 4). 

In all but the replicate sample at 9,438 m, aluminum, arsenic, 

copper, iron, lead, and silver were substantially in the colloidal 

phase. Cadmium and zinc were partly colloidal in some of the 

samples, but the remaining metals were mostly in the filtered 

phase. These metals commonly form or are sorbed to colloids 

in streams affected by mine drainage (Kimball and others, 

1995; Nordstrom and Alpers, 1999; Smith, 1999), particularly 

in the pH range of these Silver Creek samples. The presence of 

these metals in the colloidal phase suggests they may present a 

chronic toxicity problem in addition to the acute toxicity.

Principal Locations of Mass Loading

Detailed longitudinal profiles of loading along the 

study reach come from the combination of the spatially 

detailed discharge and chemical data and indicate where the 

most substantial loads enter the stream. Although the three 

separate injection reaches were studied on different days 

and under different flow regimes, the combination of results 

from all three can be unified to present a profile for the entire 

stream. This combination was accomplished by calculating 

significant changes (using equation 5) for each stream segment 

within each injection reach. These significant changes were 

then summed incrementally along each injection reach. 

The resulting load at the end of the upper injection reach 

was then used as the starting load for the middle injection 

reach. Likewise, the sum of changes at the end of the middle 

injection reach was used as the starting load for the lower 

injection reach. 

This calculation leads to a detailed longitudinal profile 

of mass loading for each element that represents sums of 

significant changes along the entire study reach. Note that 

the profile calculated in this manner does not represent the 

absolute load. For almost all the constituents, the profile can 

be summarized with reference to five principal locations, 

summarized in table 7, that account for most of the mass 

loading along the study reach. Three of the locations consist of 

only one stream segment (1, 4, and 5), while two locations are 

sums of the load contributions from several stream segments 

(2 and 3). Photographs of some of the principal locations 

are shown in figure 2. Mass loading at these five principal 

locations is illustrated with the load profiles of sulfate, 

aluminum, and zinc (figs. 9, 10, and 11, respectively).

Upstream from the Study Reach

The first stream segment, represented by the load at 0 

m, indicates the net loading from all upstream sources (fig. 

2A). Metal loading has been documented at several locations 

upstream from the study reach (Kimball and others, 2004). 

These upstream sources contribute more than 10 percent of the 

cumulative instream loads of calcium, magnesium, sodium, 

potassium, sulfate, chloride, aluminum, barium, chromium, 

and strontium. For example, sulfate load (fig. 9A) at the 

upstream end of the study reach was greater than 1,300 kg/

day; this segment contributed the second largest load of any 

individual stream segment for sulfate (fig. 9B).

Upper Meadow Tailings Piles

Six stream segments, from 2,171 m to 2,757 m (fig. 2B) 

represent the next principal location of mass loading. This 

stream reach is notable for the increase in loads of several 

metals, including aluminum (41 percent of total load), barium 

(31 percent), cadmium (23 percent), copper (23 percent), 

iron (33 percent), lead (19 percent), nickel (29 percent), and 

strontium (19 percent). This stream reach had the greatest 

loading for aluminum (fig. 10B), but the loadings of sulfate 

(fig. 9B) and zinc (fig. 11B) were relatively small in this 

stream reach. The sampled inflow load of aluminum for 

this area was about twice the sampled instream load (fig. 

10A). This result indicates that either the sampled inflow 

concentrations at the three inflows upstream from 2,171 

m were higher than the concentration of aluminum that 

actually affected the stream load, or else there was substantial 
18 Principal Locations of Metal Loading from Flood-Plain Tailings, Lower Silver Creek, Utah, April 2004

Table 7. Summary of principal locations of mass loading for Silver Creek, Utah, April 2004.

[<, less than]

Constituent

Area

Total

1 2 3 4 5 Others

Loading 

upstream 

from the 

study 

reach

Upper 

meadow 

tailings 

piles

Lower 

meadow 

tailings 

piles

Upstream 

from Pivotal 

Promontory 

access road

Downstream 

from waste-water 

treatment plant; 

Big 4 tailings

Sum of all 

other 

segments

Sum of all 

segments

Stream reach, in meters

0, start of study 

reach

2,171-2,337 

2,337-2,519 

2,519-2,637 

2,637-2,757

4,403-4,800 

4,800-5,251 

5,251-5,624 

5,624-5,950 

5,950-6,093 

6,093-6,322

6,332-7,142 8,862-8,909

Load, in kilograms per day

Calcium 725 236 980 559 480 1,098 4,078

Magnesium 184 53.6 222 121 88.3 249 919

Sodium 705 158 265 289 540 537 2,494

Potassium 14.1 2.31 15.4 14.9 31.1 35.4 113

Sulfate 1,320 443 1,877 1,400 683 2,019 7,743

Chloride 1,630 328 1,000 967 1,190 1,063 6,179

Silicon 16.2 9.29 22.3 27.6 28.8 72.6 177

Aluminum .067 .213 .115 .048 .032 .043 .518

Arsenic .010 .002 .063 .008 .018 .053 .154

Barium .304 .505 .061 .168 .134 .449 1.62

Cadmium .012 .145 .138 .122 < .001 .206 .623

Chromium .002 .001 .011 .000 .001 .002 .017

Copper .009 .052 .079 .028 .008 .052 .228

Iron .061 .749 .713 .281 .042 .431 2.28

Lead .007 .031 .030 .024 < .001 .071 .163

Manganese 1.41 .813 5.31 3.32 < .001 5.14 16.0

Molybdenum .007 .009 .008 .006 .048 .017 .095

Nickel .012 .038 .027 .030 < .001 .023 .130

Strontium 3.53 4.24 3.70 3.41 1.78 5.70 22.4

Zinc 5.98 9.90 40.5 27.5 < .001 41.0 125
Summary and Conclusions 19

precipitation of aluminum from the stream before the 

samples were collected at 2,171 m. The kinetics of aluminum 

precipitation as hydroxide phases are rapid, and at the 

relatively high pH of Silver Creek, rapid precipitation is likely 

(Broshears and others, 1996; Lydersen and others, 1991).

Lower Meadow Tailings Piles

Six stream segments, from 4,403 m to 6,322 m, 

represent the lower meadow mass loading (fig. 2C and D). 

This area was important for loading of several constituents, 

including calcium, magnesium, sulfate, aluminum, arsenic, 

chromium, copper, iron, nickel, and zinc. Zinc loading was 

particularly important, and the sum of the six stream-segment 

contributions resulted in the largest contribution of zinc along 

the entire study reach (fig. 11B). 

Upstream from Pivotal Promontory Access Road

A single segment, from 6,332 m to 7,120 m, accounts 

for a substantial amount of the total mass loading (fig. 2C). 

This single segment contributed more than 10 percent of the 

total load for every constituent except aluminum, arsenic, and 

chromium. The pond upstream from the access road (fig. 2C) 

area may be a result of ground-water discharge to the stream 

and merits further study. 

Waste-Water Treatment Plant and Old Big 4 Mill 

Tailings

Another single segment, from 8,862 m to 8,909 m, is the 

last principal location of mass loading to the stream (fig. 2D). 

The single segment that receives discharge from the WWTP 

also receives inflow from the right bank that drains tailings. 

This location differs from the other four principal locations 

of loading because it essentially contributed no cadmium, 

manganese, lead, nickel, or zinc load (table 7). Individual 

discharge measurements were not made on these two inflows, 

but chemical mass balance indicates that the metal loading that 

did occur came principally from the tailings while major ion 

loading came from the WWTP.

Other Sources

The sum of all other stream segments (table 7) indicates 

the importance of dispersed locations of mass loading. 

Contributions of metals from other areas of the study reach 

are substantial for calcium, magnesium, potassium, sulfate, 

silica, arsenic, cadmium, lead, and zinc. These dispersed metal 

loadings reflect the widespread occurrence of tailings along 

the study reach. Tailings are not just localized in the principal 

locations where loading occurred.

Comparison between 2002 and 2004

Comparison of the loads between the 2002 and 2004 

studies can help evaluate whether loads from 2004 were high 

because of the storm and snowmelt runoff. Four sampling 

points were common between the two studies, and the 

relation of zinc loads for the two studies is shown in figure 

12. Although zinc load in 2004 was initially smaller than zinc 

load in 2002 both upstream and downstream from Richardson 

Flat (fig. 12, bars A and B), the 2004 load upstream from 

the WWTP (bar C) was substantially greater than the load in 

2002. Part of the difference is a result of the diversion of flow 

for this study at 1,492 m. This additional water in the channel 

could have released the zinc from the streambed or facilitated 

release of greater loads from the tailings piles. However, even 

though the 2004 loads are much greater, the pattern of loading 

that indicates the principal locations of loading is still valid.

Summary and Conclusions

Detailed mass-loading profiles provide information 

to facilitate science-based decisions about targets for 

remediation. The significance of any particular source must 

be evaluated in the context of its metal loading. The study 

done on the southern portion of lower Silver Creek in Summit 

County, Utah, by the U.S. Geological Survey in cooperation 

with the Utah Department of Environmental Quality, Division 

of Water Quality, has provided discharge and chemical data 

to develop mass-loading profiles to indicate the principal 

locations where historical mill tailings are sources of metal 

load to the stream. Discharge was estimated by using a 

bromide tracer injection in three separate injection reaches. 

Although storms occurred between the injections, causing 

changes in discharge, the discharge values obtained in the 

separate injections were adequate to combine for mass-loading 

profiles. Detailed synoptic sampling provided an indication of 

the types of inflows affecting Silver Creek and also the major 

changes in stream chemical character along the study reach. 

These changes corresponded to the principal locations of metal 

loading to the stream, including (1) the beginning of the study 

reach, where an accounting of loading from upstream sources 

was possible, (2) the upper meadow tailings piles, from 

ground-water discharge, (3) the lower meadow tailings piles, 

from ground-water discharge, (4) the stream segment upstream 

from the Pivotal Promontory access road (6,322 m – 7,142 

m), and (5) the stream segment where WWTP and additional 

ground-water discharge from Old Big 4 tailings occurs (8,862 

m – 8,909 m). With loading data these principal sources can be 

appropriately compared.
20 Principal Locations of Metal Loading from Flood-Plain Tailings, Lower Silver Creek, Utah, April 2004

0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000

-250

0

250

500

750

1,000

1,250

1,500

0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000

0

1,500

3,000

4,500

6,000

7,500

9,000

Ditch from Richardson Flat

B

CHANGE IN SULFATE LOAD, IN KILOGRAMS PER DAY

DISTANCE ALONG STUDY REACH, IN METERS

 Sampled load

 Unsampled load

 Loss

Sources upstream from

study reach

Start of middle reach

Stream gathered in channel

Start of lower reach

Irrigation return

5 3 4

2

 DISTANCE ALONG STUDY REACH, IN METERS

 Dissolved load

 Cumulative instream load

 Cumulative inflow load

A

SULFATE LOAD, IN KILOGRAMS PER DAY

Ditch from Richardson Flat

Start of middle reach

Stream gathered in channel

Start of lower reach

Irrigation return

1

Waste-water treatment plant inflow Waste-water treatment plant inflow

2 Number indicates area of principal loading

Figure 9. (A) Variation of sulfate load with distance along the study reach and (B) change in sulfate load for individual stream 

segments, Silver Creek, Utah, April 2004.
Summary and Conclusions 21

0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000

0.0

0.3

0.6

0.9

1.2

1.5

Ditch from Richardson Flat

B

DISTANCE ALONG STUDY REACH, IN METERS

 Sampled load

 Unsampled load

 Loss

Sources upstream from

study reach

Start of middle reach

Stream gathered in channel

Start of lower reach

Irrigation return

4 5

2 3

 DISTANCE ALONG STUDY REACH, IN METERS

 Dissolved load

 Cumulative instream load

 Cumulative inflow load

A

ALUMINUM LOAD, IN KILOGRAMS PER DAY

Ditch from Richardson Flat

Start of middle reach

Stream gathered in channel

Start of lower reach

Irrigation return

1

CHANGE IN ALUMINUM LOAD,

IN KILOGRAMS PER DAY

Waste-water treatment plant inflow Waste-water treatment plant inflow

2 Number indicates area of principal loading

Figure 10. (A) Variation of aluminum load with distance along the study reach and (B) change in aluminum load for individual stream 

segments, Silver Creek, Utah, April 2004.
22 Principal Locations of Metal Loading from Flood-Plain Tailings, Lower Silver Creek, Utah, April 2004

0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000

-15

-10

-5

0

5

10

15

20

25

30

0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000

0

40

80

120

160

200

240

280

Ditch from Richardson Flat

B

DISTANCE ALONG STUDY REACH, IN METERS

 Sampled load

 Unsampled load

 Loss

Sources upstream from

study reach

Start of middle reach

Stream gathered in channel

Start of lower reach

Waste-water

treatment plant inflow

Irrigation return

2 3 4 5

 DISTANCE ALONG STUDY REACH, IN METERS

 Dissolved load

 Cumulative instream load

 Cumulative inflow load

A

ZINC LOAD, IN KILOGRAMS PER DAY

Ditch from Richardson Flat

Start of middle reach

Stream gathered in channel

Start of lower reach

Irrigation return

1

Waste-water

treatment plant inflow

CHANGE IN ZINC LOAD, IN KILOGRAMS PER DAY

2 Number indicates area of principal loading

Figure 11. (A) Variation of zinc load with distance along the study reach and (B) change in zinc load for individual stream segments, 

Silver Creek, Utah, April 2004.
References Cited 23

A B C D 0

10

20

30

40

50

60

70

80

90

100

110

120

130

ZINC LOAD, IN KILOGRAMS PER DAY

COMMON SAMPLING SITES

 2002

 2004

Upstream from Richardson Flat

Downstream from Richardson Flat

Upstream from

waste-water treatment plant

Downstream from

waste-water treatment plant

Figure 12. Zinc load at common sampling sites from studies in 

2002 and 2004, Silver Creek, Utah.

References Cited 

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instream variability: Sampling iron in an acidic stream, in

Averett, R.C., and McKnight, D.M., eds., Chemical Quality 

of Water and the Hydrologic Cycle: Chelsea, Mich., Lewis 

Publishers, Inc., p. 255-269.

Bromfield, C.S., 1989, Gold deposits in the Park City Mining 

District, Utah: U.S. Geological Survey Bulletin 1857, 26 p.

Broshears, R.E., Runkel, R.L., Kimball, B.A., Bencala, K.E., 

and McKnight, D.M., 1996, Reactive solute transport in an 

acidic stream: Experimental pH increase and simulation of 

controls on pH, aluminum, and iron: Environmental Science 

& Technology, v. 30, no. 10, p. 3016-3024.

Friedman, L.C., and Erdmann, D.E., 1982, Quality assurance 

practices for the chemical and biological analyses of water 

and fluvial sediments: U.S. Geological Survey Techniques 

of Water-Resources Investigations, book 5, chap. A6, 181 p.

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the Park City District, in Erickson, A.J., Jr., Phillips, W.R., 

and Garmoe, W.J., eds., Park City District, Utah: Salt Lake 

City, Utah, Utah Geological Society, p. 30-39.

Giddings, E.M., Hornberger, M.I., and Hadley, H.K., 2001, 

Trace-metal concentrations in sediment and water and 

health of aquatic macroinvertebrate communities of streams 

near Park City, Summit County, Utah: U.S. Geological Survey Water-Resources Investigations Report 01-4213, 22 p.

Kaufman, L., and Rousseeuw, P.J., 1990, Finding groups in 

data: An introduction to cluster analysis: New York, Wiley, 

368 p.

Kilpatrick, F.A., and Cobb, E.D., 1985, Measurement of discharge using tracers: U.S. Geological Survey Techniques of 

Water-Resources Investigations, book 3, chap. A16, 27 p.

Kimball, B.A., Callender, E., and Axtmann, E.V., 1995, 

Effects of colloids on metal transport in a river receiving acid mine drainage, upper Arkansas River, Colorado, 

U.S.A.: Applied Geochemistry, v. 10, p. 285-306.

Kimball, B.A., Johnson, K.K., Runkel, R.L., and Steiger, 

J.I., 2004, Quantification of metal loading to Silver Creek 

through the Silver Maple Claims area, Park City, Utah, May 

2002: U.S. Geological Survey Water-Resources Investigations Report 03-4296, 40 p.

Kimball, B.A., Nordstrom, D.K., Runkel, R.L., Vincent, K.R., 

and Verplanck, P.L., 2006a, Questa baseline and pre-mining 

ground-water quality investigation. 23. Quantification of 

mass loading from mined and unmined areas along the 

Red River, New Mexico: U.S. Geological Survey Scientific 

Investigations Report 2006-5004, 53 p.

Kimball, B.A., Runkel, R.L., and Walton-Day, K., 2003, Use 

of field-scale experiments and reactive solute-transport 

modelling to evaluate remediation alternatives in streams 

affected by acid mine drainage, in Jambor, J.L., Blowes, 

D.W., and Ritchie, A.I.M., eds., Environmental aspects of 

mine wastes: Vancouver, British Columbia, Mineralogical 

Association of Canada, p. 261-282.

Kimball, B.A., Runkel, R.L., Walton-Day, K., and Bencala, 

K.E., 2002, Assessment of metal loads in watersheds 

affected by acid mine drainage by using tracer injection and 

synoptic sampling: Cement Creek, Colorado, USA: Applied 

Geochemistry, v. 17, no. 9, p. 1183-1207.

Kimball, B.A., Runkel, R.L., Walton-Day, K., and Williamson, 

J.E., 2006b, Quantification of mass loading to Strawberry 

Creek near the Gilt Edge mine, South Dakota: U.S. Geological Survey Scientific Investigations Report 2006-5006, 

41 p.

Lydersen, E., Salbu, B., Paleo, A.B.S., and Muniz, I.P., 1991, 

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metal and arsenic concentrations in the surface water of the 

Clark Fork River Basin, Montana: University of Montana, 

Master of Science thesis, 115 p.
24 Principal Locations of Metal Loading from Flood-Plain Tailings, Lower Silver Creek, Utah, April 2004

Michael Baker Jr., Inc., 2004, Silver Creek Total Maximum 

Daily Load for dissolved zinc and cadmium: Utah Department of Environmental Quality, Division of Water Quality, 

accessed April 3, 2005, at http://www.waterquality.utah.gov/

TMDL/Silver_Creek_TMDL.pdf

Nichols, D.J., and Bryant, Bruce, 1990, Geologic map of the 

Salt Lake City 30’ x 60’ quadrangle, north-central Utah, 

and Uinta County, Wyoming: U.S. Geological Survey IMap 

1944, scale 1:100,000.

Nordstrom, D.K., and Alpers, C.N., 1999, Geochemistry of 

acid mine waters, in Plumlee, G.S., and Logsdon, M.J., eds., 

The environmental geochemistry of mineral deposits Part 

A: Processes, techniques, and health issues: Littleton, Colo., 

Society of Economic Geologists, p. 133-160.

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Kokaly, R.F., and Vance, J.S., 1999, Preliminary materials 

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the 8th annual JPL airborne earth science workshop: JPL 

Publication, p. 365-375.

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resources data, Utah, Water year 2003: U.S. Geological 

Survey Water-Data Report UT-03-1, 458 p.

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of quality for waters of the State: Division of Administrative 

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publicat/code/r317/r317-002.htm

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and computing of exploratory data analysis: Boston, Mass., 

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perspective: U.S. Geological Survey Fact Sheet 037-03, 6 p.
Table 2 25

Table 2. Bromide concentration of synoptic water samples and characteristics of the sites at which the samples were collected, Silver 

Creek, Utah, April 2004.

[Source: S, stream; LBI, left-bank inflow; RBI, right-bank inflow; Bromide: mg/L, milligrams per liter; Discharge: L/s, liters per second; NC, not calculated; NM, 

not measured; <, less than]

Sample 

identification

Distance, 

(meters) Source Description Northing, (meters)

Easting, 

(meters)

Sample date 

and time

Bromide, 

(mg/L)

Discharge, 

(L/s)

Upper injection reach

SQ1-0000 0 S T0 Upper - Injection site below U.S. Highway 

40 bridge

4503080 461067 4/15/04 11:57 0.13 53.2

SQ1-0061 61 LBI Discharge with iron staining from willows 4503135 461094 4/15/04 11:53 .58 NC

SQ1-0101 101 S Upstream from “upstream tailings” 4503166 461120 4/15/04 11:46 4.14 53.2

SQ1-0250 250 S Midway along the tailings in the left bank 4503278 461186 4/15/04 11:41 4.23 53.2

SQ1-0428A 428 S T1 Upper - Upstream from Richardson Flat tailings influence4503443 461292 4/15/04 11:35 4.11 53.2

SQ1-0428B 428 S T1 Upper - Upstream from Richardson Flat tailings influence4503443 461292 4/15/04 11:36 3.98 53.2

SQ1-0525 525 S Upstream from pond area and bridge 4503456 461289 4/15/04 11:25 4.24 53.2

SQ1-0625 625 LBI Pace-Homer ditch inflow; left of bridge 4503635 461337 4/15/04 11:20 3.25 NC

SQ1-0681 672 LBI Small ditch upstream from highway 4503706 461323 4/15/04 11:03 1.79 NC

SQ1-0682 682 LBI Black pipe spewing orange floc; source unknown4503716 461326 4/15/04 10:58 1.28 NC

SQ1-0731 731 S Downstream end of left, smaller culvert at 

highway

4503751 461331 4/15/04 13:16 4.22 NC

SQ1-0757 757 LBI Ditch downstream from highway 4503764 461316 4/15/04 10:31 3.63 NC

SQ1-0770 770 LBI Draining ditch on downstream side of highway 4503790 461331 4/15/04 10:01 < .03 NC

SQ1-0861 861 S Right channel - downstream end of larger culvert 

at highway

4503690 461409 4/15/04 10:15 2.07 NC

SQ1-1050 1,050 RBI Right channel - ditch from area of Richardson 

Flat

4503814 461499 4/15/04 10:08 .24 NC

SQ1-1095 1,095 S Upstream end of culvert under rail trail 4503991 461348 4/15/04 9:55 4.01 NC

SQ1-1148 1,148 RBI Right channel - second ditch from area of Richardson Flat?4503896 461517 4/15/04 9:52 3.59 NC

SQ1-1229 1,229 S Right channel - downstream from small pond in 

channel

4504001 461523 4/15/04 9:41 1.97 NC

SQ1-1235 1,235 RBI Channel draining meadow area 4504147 461456 4/15/04 9:49 .16 NC

SQ1-1300 1,300 S Upstream from return of irr ditch 4504211 461461 4/15/04 9:18 3.87 NC

SQ1-1309 1,309 RBI T2 Upper - Right channel - returning ditch 4504220 461465 4/15/04 13:25 2.01 NC

SQ1-1371A 1,371 S At old flume in stream 4504277 461445 4/15/04 9:13 3.30 64.0

SQ1-1371B 1,371 S At old flume in stream 4504277 461445 4/15/04 9:14 3.30 64.0

SQ1-1452 1,452 S T3 Upper - At diversion to wetland 4504334 461388 4/15/04 9:07 3.17 66.8

SQ1-1744 1,744 S Irrigation ditch blw culvert near wetland; 2002 

sample site

4504394 461305 4/15/04 9:26 NM NM

Middle injection reach

SQ2-1601 1,601 S T0 Middle - Injection site downstream from 

wetland culvert

4504379 461263 4/9/04 11:55 .11 70.9

SQ2-1843B 1,843 S T1 Middle - At fence at end of wetland 4504455 461182 4/9/04 11:50 2.63 70.9

SQ2-1843C 1,843 S T1 Middle - At fence at end of wetland 4504455 461182 4/9/04 11:51 2.58 70.9

SQ2-1843A 1,843 S T1 Middle - At fence at end of wetland 4504455 461182 4/9/04 8:58 2.47 70.9

SQ2-1959 1,959 S Upstream from tailings inflow - questioned 

chemistry

4504540 461108 4/9/04 11:57 2.49 70.9

SQ2-1965 1,965 RBI Pond at end of long talings pile 4504550 461114 4/9/04 11:10 .14 NC

SQ2-2048 2,048 RBI Location of several inflows 4504602 461073 4/9/04 11:04 2.58 NC

SQ2-2118 2,118 RBI Homer Spring inflow to irrigation ditch; no input 

to stream

4504707 461143 4/9/04 11:08 .03 NM

SQ2-2171 2,171 S Downstream from area of right bank inflows 4504698 461039 4/9/04 12:00 2.60 70.9

SQ2-2337 2,337 S After braids have come back together 4504854 460993 4/9/04 12:07 2.64 70.9

SQ2-2387 2,387 LBI Near tailings piles on right bank 4504904 460970 4/9/04 10:50 .91 NC
26 Principal Locations of Metal Loading from Flood-Plain Tailings, Lower Silver Creek, Utah, April 2004

Table 2. Bromide conentration of synoptic water samples and characteristics of the sites at which the samples were collected, Silver 

Creek, Utah, April 2004—Continued. 

Sample 

identification

Distance, 

(meters) Source Description Northing, (meters)

Easting, 

(meters)

Sample date 

and time

Bromide, 

(mg/L)

Discharge, 

(L/s)

Middle injection reach—Continued

SQ2-2431 2,447 LBI Drains large area with tailings off to left 4504936 460948 4/9/04 10:45 .24 NC

SQ2-2560 2,519 S Between upstream left bank inflows and downstream right bank inflows4505061 460919 4/9/04 12:13 2.42 78.4

SQ2-2569 2,528 RBI Drains from tailings pile 4505069 460916 4/9/04 10:42 < .03 NC

SQ2-2678 2,637 S Downstream from tailings inflow; to collect 

inflows

4505174 460886 4/9/04 12:20 2.28 84.0

SQ2-2718 2,677 RBI Pond from tailings drainage 4505213 460880 4/9/04 10:36 .17 NC

SQ2-2730 2,757 S At fence below property corner 4505275 460870 4/9/04 12:24 2.14 86.5

SQ2-2785 2,847 S Downstream from where stream cuts through 

corner of property

4505276 460872 4/9/04 12:33 2.32 88.3

SQ2-2780 2,892 RBI Direct drainage from tailings pile with Ulothrix 4505410 460823 4/9/04 10:30 1.92 NC

SQ2-2810 2,927 S At old skull in stream 4505430 460789 4/9/04 12:28 2.16 89.9

SQ2-3027 3,144 LBI Drains flat area; no tailings piles visible 4505480 460761 4/9/04 10:19 1.37 NC

SQ2-3045 3,162 RBI Draining from tailings piles 4505495 460766 4/9/04 10:17 1.82 NC

SQ2-3254B 3,371 S T2 Middle - Upstream from old tree 4505676 460685 4/9/04 12:41 2.28 96.3

SQ2-3254A 3,371 S T2 Middle - Upstream from old tree 4505676 460685 4/9/04 21:54 2.09 96.3

SQ2-3379 3,496 S Downstream from area where stream is ponded 4505790 460634 4/9/04 12:46 2.00 98.1

SQ2-3598 3,715 RBI Small pool on right bank; sample puddle 4505963 460558 4/9/04 10:04 .33 NC

SQ2-3602 3,719 LBI Drains tailings to left of stream 4505965 460544 4/9/04 10:01 .84 NC

SQ2-3784A 3,901 S Upstream from point where flow disperses; 

made a new diversion to right

4506113 460461 4/9/04 12:55 2.03 100

SQ2-3784B 3,901 S Upstream from point where flow disperses; 

made a new diversion to right

4506113 460461 4/9/04 12:56 2.03 100

SQ2-4000 4,117 RBI Inflow from natural channel; ditch from left of 

rail trail; strm water

4506264 460493 4/9/04 9:52 .81 NC

SQ2-4050 4,167 S Location to check with discharge measurement 

and Br

4506351 460427 4/9/04 13:04 1.87 106

SQ2-4286 4,403 S After gathering back together into channel; 

could be irrigation ditch

4506561 460311 4/9/04 13:10 1.75 116

SQ2-4292 4,409 LBI Draining area where stream dispersd 4506560 460310 4/9/04 9:44 .25 NC

SQ2-0054 4,517 LBI Draining wide area to left of stream 4506643 460231 4/9/04 9:40 .43 NC

SQ2-0061 4,800 S Downstream from gathered dispersion 4506713 460011 4/9/04 13:19 2.22 122

SQ2-0080 5,251 S Downstream from area where stream is ponded 4507164 460015 4/9/04 13:32 1.57 133

SQ2-0096 5,493 RBI Drainage has some flow to stream; tailings in 

soil to right

4507409 460024 4/9/04 9:23 .35 NC

SQ2-0100 5,624 S Downstream from possible tailings inflow 4507538 460003 4/9/04 13:39 1.49 143

SQ2-0108 5,833 RBI Orange stained inflow 4507710 459965 4/9/04 9:15 < .03 NC

SQ2-0109 5,843 RBI Draining tailings 4507703 459959 4/9/04 10:15 .26 NC

SQ2-0149 5,878 RBI Sample away from stream; water not draining to 

stream

4507755 459965 4/9/04 9:12 < .03 NC

SQ2-0113 5,950 S Upstream from many tailings mounds 4507805 459931 4/9/04 13:50 1.34 145

SQ2-0120 6,045 RBI Draining tailings, maybe from storm, orange 

plume

4507870 459866 4/9/04 9:05 .06

SQ2-0122 6,093 S To account for inflows and separate tailings 

below

4507907 459836 4/9/04 13:55 1.87 146

SQ2-0135 6,322 S T3 Middle - Upstream from pond above Promontory Road4508017 459664 4/9/04 14:04 1.45 147

SQ2-0137 6,353 RBI Orange inflow; farther right 4508045 459653 4/9/04 8:55 .63 NC

SQ2-0005 7,259 S End of middle injection reach 4508154 459567 4/9/04 14:12 1.48 177
Table 2 27

Table 2. Bromide conentration of synoptic water samples and characteristics of the sites at which the samples were collected, Silver 

Creek, Utah, April 2004—Continued. 

Sample 

identification

Distance, 

(meters) Source Description Northing, (meters)

Easting, 

(meters)

Sample date 

and time

Bromide, 

(mg/L)

Discharge, 

(L/s)

Lower injection reach

SQ3-005 7,142 S T0 Lower - Injection site downstream from 

Promontory culvert

4508154 459567 4/6/04 12:20 .29 53.8

SQ3-008 7,161 S First site downstream from injection for discharge4508170 459557 4/6/04 12:22 7.37 53.8

SQ3-010 7,185 RBI Draining tailings toward old “Big 4” mill site 4508186 459550 4/6/04 11:35 2.17 NC

SQ3-012 7,208 S T1 Lower - Downstream from first tailings 

inflow

4508206 459530 4/6/04 12:30 7.78 53.8

SQ3-018 7,276 S To capture right bank inflows 4508258 459504 4/6/04 12:35 7.52 55.8

SQ3-024 7,365 RBI Ponds along berm line to east 4508333 459470 4/6/04 11:30 .08 NC

SQ3-025 7,366 LBI Draing from pond toward BFI Disposal land 4508333 459462 4/6/04 11:25 .28 NC

SQ3-032 7,397 S To capture both inflow upstream 4508385 459469 4/6/04 12:40 7.32 57.3

SQ3-039 7,470 S Upstream from inflow from marsh draining 

along fence

4508519 459468 4/6/04 12:45 7.27 57.7

SQ3-042 7,491 LBI Draining from marsh area along much of BFI 

land

4508512 459419 4/6/04 11:20 .85 NC

SQ3-048 7,571 S Downstream from inflow along fence 4508596 459474 4/6/04 12:50 6.86 59.9

SQ3-056 7,687 S Downstream from area where stream is ponded 4508682 459466 4/6/04 12:55 6.91 60.9

SQ3-060 7,730 LBI Draining tailings toward old mill site; pool away 

from stream

4508724 459465 4/6/04 11:10 .76 NC

SQ3-066 7,825 S Near right bank talings in flood plain 4508802 459510 4/6/04 13:00 6.91 60.9

SQ3-083 8,009 RBI Small, unconnected pools along ditch 4508923 459558 4/6/04 11:05 .13

SQ3-097 8,225 S Downstream from tailings inflows on both sides 

of stream

4509047 459627 4/6/04 13:10 6.92 60.9

SQ3-115 8,449 RBI Pond on right bank away from stream 4509256 459651 4/6/04 10:50 .13 NC

SQ3-121 8,497 LBI Draining in small grassy channel 4509258 459596 4/6/04 10:45 .27 NC

SQ3-127 8,591 S Gathering of the upstream inflows 4509340 459649 4/5/04 13:15 7.22 60.9

SQ3-131 8,701 LBI Pond by waste-water treatment plant 4509394 459683 4/6/04 10:38 .13 NC

SQ3-140 8,862 S T2 Lower - Upstream from waste-water treatment plant inflow4509453 459779 4/6/04 13:22 7.29 60.9

SQ3-141 8,881 LBI Discharge from waste-water treatment plant 4509467 459792 4/6/04 10:22 .13 NC

SQ3-142 8,886 RBI Drains area to right including pond 4509471 459795 4/6/04 10:11 .11 NC

SQ3-145 8,909 S Stream below gage and waste-water treatment 

plant inflow

4509493 459803 4/5/04 13:34 3.99 96.3

SQ3-172 9,355 S Upstream from irrigation return flow 4509894 459888 4/6/04 13:45 4.50 96.3

SQ3-173 9,360 RBI Return flow from irrigation ditch, through dairy 

farm

4509899 459889 4/6/04 9:54 .40 NC

SQ3-178A 9,438 S Downstream from irrigation return flow 4509965 459867 4/6/04 13:48 4.22 103

SQ3-178B 9,438 S Downstream from irrigation return flow 4509965 459867 4/6/04 13:50 4.22 103

SQ3-186 9,562 LBI Discharge from stream on left 4510076 459820 4/6/04 9:48 .03 NC

SQ3-189 9,598 LBI Seep inflow of very high conductance 4510111 459829 4/6/04 9:45 .13 NC

SQ3-193 9,719 S Dowstream from high conductance seeps 4510190 459901 4/6/04 13:58 3.81 115

SQ3-194 9,725 RBI Draining dairy farm 4510194 459905 4/6/04 9:34 .06 NC

SQ3-196 9,747 S T3 Lower - Downstream from bridge to dairy 4510215 459905 4/6/04 14:00 3.65 121
28 Principal Locations of Metal Loading from Flood-Plain Tailings, Lower Silver Creek, Utah, April 2004

Table 3. Concentration of major ions in synoptic water samples collected along Silver Creek, Utah, April 2004.

[Source: S, stream; LBI, left-bank inflow; RBI, right-bank inflow; Filter: FA, filtered acidified; RA, unfiltered acidified; Temperature: °C, degrees Celsius; pH, 

in standard units; mg/L, milligrams per liter; NV, no value; <, less than; NR, not recorded]

Sample 

identification

Distance

(meters) Source Filter

Temperature

(°C)

pH Calcium

(mg/L)

Magnesium

(mg/L)

Sodium

(mg/L)

Potassium

(mg/L)

Alkalinity 

as CaCO3

(mg/L)

Sulfate

(mg/L)

Chloride

(mg/L)

Silica

as Si

(mg/L)

SQ1-0000 0 S FA 7.0 8.06 158 40.1 153 3.06 135 286 354 3.53

SQ1-0061 61 LBI FA 9.0 7.68 231 54.5 117 2.33 188 424 332 8.25

SQ1-0101 101 S FA 7.5 8.04 158 39.7 153 2.91 137 287 357 3.65

SQ1-0250 250 S FA 7.5 8.01 159 40.1 156 2.87 134 286 361 3.65

SQ1-0428A 428 S FA 7.0 8.04 166 41.4 160 2.91 132 291 367 3.68

SQ1-0428B 428 S FA 7.0 8.01 163 41.0 158 2.90 134 293 365 3.72

SQ1-0525 525 S FA 7.0 8.08 162 40.6 157 2.86 135 291 369 3.96

SQ1-0625 625 LBI FA 7.0 7.89 194 47.4 152 3.36 141 318 383 4.76

SQ1-0681 672 LBI FA 6.5 7.60 225 58.5 238 3.17 150 270 687 6.76

SQ1-0682 682 LBI FA 9.0 6.94 267 67.8 213 2.28 174 551 568 9.41

SQ1-0731 731 S FA 6.5 7.93 168 42.1 166 3.03 137 297 393 4.04

SQ1-0757 757 LBI FA 7.0 7.95 172 42.8 169 2.92 137 297 392 3.48

SQ1-0770 770 LBI FA 7.0 7.62 463 96.8 646 3.14 156 194 1,880 7.90

SQ1-0861 861 S FA 6.0 7.82 179 41.9 123 2.92 160 337 281 6.09

SQ1-1050 1,050 RBI FA 6.0 7.87 218 45.2 130 5.71 178 322 379 NV

SQ1-1095 1,095 S FA 6.0 8.01 177 43.9 177 3.04 138 295 426 4.01

SQ1-1148 1,148 RBI FA 5.5 7.90 189 46.0 182 3.03 141 309 442 3.86

SQ1-1229 1,229 S FA 5.0 7.84 185 42.9 123 3.23 165 344 291 7.11

SQ1-1235 1,235 RBI FA 5.0 7.35 286 72.6 116 4.03 157 761 307 12.2

SQ1-1300 1,300 S FA 6.0 7.96 182 44.3 178 3.03 141 304 434 4.12

SQ1-1309 1,309 RBI FA 5.5 7.81 184 42.2 120 3.22 167 344 294 7.45

SQ1-1371A 1,371 S FA 5.5 7.91 185 43.9 158 3.12 149 316 374 4.95

SQ1-1371B 1,371 S FA 5.5 7.97 184 43.9 157 3.11 148 315 375 5.00

SQ1-1452 1,452 S FA 5.5 7.98 181 43.6 154 2.97 149 320 375 5.10

SQ2-1601 1,601 S FA NR 8.12 163 39.4 143 3.30 141 302 338 6.73

SQ1-1744 1,744 S FA 4.0 7.25 230 60.2 152 3.70 158 525 386 9.98

SQ2-1843A 1,843 S FA NR 8.12 167 39.4 160 3.40 144 292 361 6.63

SQ2-1843B 1,843 S FA NR 8.03 166 39.8 152 3.44 144 301 360 6.64

SQ2-1843C 1,843 S FA NR 7.95 167 39.9 153 3.34 144 300 359 6.67

SQ2-1959 1,959 S FA NR 8.19 169 40.5 154 3.55 145 302 362 6.77

SQ2-1965 1,965 RBI FA NR 3.36 479 286 177 4.26 < .5 3,510 492 29.7

SQ2-2048 2,048 RBI FA NR 7.79 174 40.3 144 3.57 138 343 332 7.22

SQ2-2118 2,118 RBI FA NR 8.16 44.1 10.4 17.1 2.29 125 9.41 39.7 21.8

SQ2-2171 2,171 S FA NR 8.07 172 40.1 156 3.53 140 319 371 6.93

SQ2-2337 2,337 S FA NR 8.03 175 41.5 157 3.59 142 318 374 7.23

SQ2-2431 2,447 LBI FA NR 7.95 179 47.4 123 4.13 194 104 454 8.72

SQ2-2560 2,519 S FA NR 8.01 179 42.4 154 3.59 140 321 386 7.34

SQ2-2569 2,528 RBI FA NR 7.03 275 67.0 140 7.16 127 730 361 15.8

SQ2-2678 2,637 S FA NR 7.98 180 42.4 154 3.57 141 330 381 7.39

SQ2-2718 2,677 RBI FA NR 7.31 247 61.9 116 4.84 176 604 301 14.7

SQ2-2730 2,757 S FA NR 7.94 184 43.3 154 3.69 141 332 384 7.56

SQ2-2785 2,847 S FA NR 7.94 186 43.5 155 3.71 142 331 382 7.67

SQ2-2780 2,892 RBI FA NR 7.80 198 45.6 152 4.22 138 365 380 8.85

SQ2-2810 2,927 S FA NR 7.94 184 43.5 155 3.75 139 331 383 7.59

SQ2-3027 3,144 LBI FA NR 7.80 193 47.1 128 4.40 142 336 363 9.82

SQ2-3045 3,162 RBI FA NR 7.76 213 48.8 148 4.71 137 411 374 9.49

SQ2-3254A 3,371 S FA NR 7.91 188 44.3 153 3.90 141 335 378 7.86

SQ2-3254B 3,371 S FA NR 7.97 187 43.9 152 3.69 141 341 377 7.83

SQ2-3379 3,496 S FA NR 7.94 190 44.8 153 3.72 141 343 380 7.95

SQ2-3598 3,715 RBI FA NR 7.27 438 117 185 10.1 85.7 1,300 469 8.45

SQ2-3602 3,719 LBI FA NR 7.35 247 63.2 123 4.09 121 600 370 12.1

SQ2-3784A 3,901 S FA NR 7.98 190 44.7 149 3.61 141 355 383 7.93

SQ2-3784B 3,901 S FA NR 7.96 192 45.2 152 3.55 141 355 383 8.09
Table 3 29

Table 3. Concentration of major ions in synoptic water samples collected along Silver Creek, Utah, April 2004—Continued.

Sample 

identification

Distance

(meters) Source Filter

Temperature

(°C)

pH Calcium

(mg/L)

Magnesium

(mg/L)

Sodium

(mg/L)

Potassium

(mg/L)

Alkalinity 

as CaCO3

(mg/L)

Sulfate

(mg/L)

Chloride

(mg/L)

Silica

as Si

(mg/L)

SQ2-4000 4,117 RBI FA NR 7.79 208 48.2 140 3.77 151 402 370 9.04

SQ2-4050 4,167 S FA NR 7.99 202 47.5 150 3.83 142 380 376 8.52

SQ2-4286 4,403 S FA NR 8.02 200 46.9 148 3.80 142 378 380 8.45

SQ2-4292 4,409 LBI FA NR 7.61 271 69.8 146 4.72 134 601 458 8.69

SQ2-0054 4,517 LBI FA NR 7.81 306 82.7 162 5.51 154 475 638 11.6

SQ2-0061 4,800 S FA NR 8.01 205 48.2 151 3.87 141 376 384 8.44

SQ2-0080 5,251 S FA NR 7.96 213 49.9 152 4.27 143 388 390 8.76

SQ2-0096 5,493 RBI FA NR 7.57 294 70.1 107 4.63 141 667 345 12.4

SQ2-0100 5,624 S FA NR 7.88 232 53.5 146 4.33 141 437 389 9.05

SQ2-0108 5,833 RBI FA NR 7.65 237 50.4 61.0 3.76 132 556 215 13.3

SQ2-0109 5,843 RBI FA NR 7.32 321 76.7 68.4 6.28 109 1,040 181 14.3

SQ2-0149 5,878 RBI FA NR 5.98 453 181 104 20.0 24.9 3,250 301 15.1

SQ2-0113 5,950 S FA NR 7.86 238 55.2 145 4.40 140 452 386 9.29

SQ2-0120 6,045 RBI FA NR 4.13 436 154 145 9.36 < .1 3,680 136 28.7

SQ2-0122 6,093 S FA NR 7.83 231 53.9 141 4.46 141 457 381 9.42

SQ2-0135 6,322 S FA NR 7.83 236 55.3 144 4.32 140 460 384 9.35

SQ2-0137 6,353 RBI FA NR 7.46 271 70.8 72.2 11.4 53.2 988 141 15.7

SQ2-0005 7,120 S FA NR 7.88 233 54.0 139 4.57 134 475 383 9.60

SQ3-005 7,142 S FA 10.5 7.97 239 61.8 147 4.49 144 538 409 10.0

SQ3-008 7,161 S FA 10.5 7.97 231 62.0 148 4.34 146 535 407 9.72

SQ3-008 7,161 S RA 10.5 7.97 243 62.7 149 4.35 146 535 407 9.98

SQ3-010 7,185 RBI FA 12.0 7.54 429 88.4 167 6.22 120 1,120 435 9.33

SQ3-010 7,185 RBI RA 12.0 7.54 424 88.4 165 6.03 120 1,120 435 8.79

SQ3-012 7,208 S FA 11.0 7.93 235 61.8 152 4.51 138 533 412 9.77

SQ3-018 7,276 S FA 10.5 7.92 241 63.0 150 4.49 142 541 413 9.83

SQ3-024 7,365 RBI FA 14.0 7.42 311 68.0 53.1 7.70 78.3 1,050 81.1 9.46

SQ3-025 7,366 LBI FA 7.0 7.09 510 123 121 6.59 80.2 1,610 423 11.0

SQ3-032 7,397 S FA 10.5 7.93 241 62.2 153 4.53 138 542 407 9.99

SQ3-032 7,397 S RA 10.5 7.93 240 61.8 147 4.37 138 542 407 9.83

SQ3-039 7,470 S FA 10.5 7.95 244 62.4 152 4.42 143 438 404 9.97

SQ3-042 7,491 LBI FA 12.0 7.69 234 65.8 185 4.17 173 333 549 13.5

SQ3-048 7,571 S FA 10.0 8.05 237 61.4 150 4.60 143 544 408 9.84

SQ3-056 7,687 S FA 9.5 8.11 239 62.6 150 4.56 141 546 414 10.2

SQ3-060 7,730 LBI FA 7.5 6.89 537 127 221 6.69 177 1,480 645 11.9

SQ3-060 7,730 LBI RA 7.5 6.89 532 128 218 6.53 177 1,480 645 11.6

SQ3-066 7,825 S FA 10.0 8.10 238 61.4 149 4.49 141 552 407 9.96

SQ3-083 8,009 RBI FA 15.0 7.53 461 89.8 94.4 10.5 96.6 1,450 177 7.27

SQ3-097 8,225 S FA 10.0 8.12 243 62.0 151 4.55 139 554 406 10.5

SQ3-115 8,449 RBI FA 5.0 7.59 52.9 10.6 24.0 .85 33.5 131 58.1 2.25

SQ3-121 8,497 LBI FA 11.0 7.50 346 73.2 140 4.93 116 976 349 11.5

SQ3-127 8,591 S FA 10.0 8.12 242 63.1 147 4.52 147 568 409 9.95

SQ3-127 8,591 S RA 10.0 8.12 239 61.2 144 4.07 147 568 409 9.64

SQ3-131 8,701 LBI FA 12.0 7.80 222 45.5 124 5.06 146 516 271 8.47

SQ3-140 8,862 S FA 10.5 8.13 261 64.6 156 4.75 142 567 411 10.2

SQ3-141 8,881 LBI FA 12.0 8.24 156 39.7 211 11.8 147 268 399 11.0

SQ3-142 8,886 RBI FA 7.0 7.93 260 58.8 74.5 3.02 206 521 262 13.0

SQ3-145 8,909 S FA 12.0 8.15 223 51.5 164 6.74 145 441 403 9.91

SQ3-145 8,909 S RA 12.0 8.15 227 53.1 170 7.43 145 441 403 10.2

SQ3-172 9,355 S FA 12.5 8.12 237 55.1 161 6.66 142 467 397 10.5

SQ3-173 9,360 RBI FA 7.5 7.91 201 49.3 62.5 6.11 188 310 247 15.9

SQ3-178A 9,438 S FA 13.0 7.87 235 54.6 158 6.74 145 458 385 11.0

SQ3-178A 9,438 S RA 13.0 7.87 239 55.2 157 6.56 145 458 385 11.2

SQ3-178B 9,438 S FA 13.0 8.12 235 54.2 154 6.57 147 460 384 10.8

SQ3-178B 9,438 S RA 13.0 8.12 260 65.4 151 4.93 147 460 384 10.6

SQ3-186 9,562 LBI FA 9.5 7.92 67.4 16.8 26.2 3.24 161 51.5 55.9 18.2
30 Principal Locations of Metal Loading from Flood-Plain Tailings, Lower Silver Creek, Utah, April 2004

Table 3. Concentration of major ions in synoptic water samples collected along Silver Creek, Utah, April 2004—Continued.

Sample 

identification

Distance

(meters) Source Filter

Temperature

(°C)

pH Calcium

(mg/L)

Magnesium

(mg/L)

Sodium

(mg/L)

Potassium

(mg/L)

Alkalinity 

as CaCO3

(mg/L)

Sulfate

(mg/L)

Chloride

(mg/L)

Silica

as Si

(mg/L)

SQ3-189 9,598 LBI FA 7.5 7.75 438 121 286 50.4 279 29.0 1,400 15.9

SQ3-193 9,719 S FA 13.0 7.82 221 51.8 145 6.50 148 422 363 11.7

SQ3-193 9,719 S RA 13.0 7.82 220 51.4 144 6.35 148 422 363 11.8

SQ3-194 9,725 RBI FA 7.0 7.64 107 20.4 24.5 10.6 230 107 61.1 16.8

SQ3-196 9,747 S FA 13.5 7.89 208 49.4 147 6.88 147 409 361 12.1

SQ3-196 9,747 S RA 13.5 7.89 216 50.4 144 6.63 147 409 361 11.9
Table 4 31

Table 4. Concentration of trace elements in synoptic water samples collected along Silver Creek, Utah, April 2004.[Distance, in meters along the study reach; Source: S, stream; LBI, left-bank inflow; RBI, right-bank inflow; Filter: FA, 0.45-micrometer filtration; RA, unfiltered acidified; chemical concentrations reported in micrograms per liter; <, less than]

Sample 

identification

Distance Source Fil- ter Alumi- num Arse- nic Bari- um Cad- mium Co- balt Chro- mium Cop- per Iron Lead Manga- nese Molyb- denum Nickel Sil- ver Stron- tium Ura- nium Vana- dium Zinc

Upper injection reach

SQ1-0000 0 S FA 14.6 2.13 66.2 2.69 0.59 0.47 1.96 13.2 1.62 308 1.50 2.63 0.01 767 1.96 0.133 1,300

SQ1-0061 61 LBI FA 14.1 1.98 67.0 24.0 .65 .36 1.63 2.55 .347 428 1.29 4.35 < .01 1,260 2.71 .404 8,800

SQ1-0101 101 S FA 15.1 1.97 68.2 2.66 .65 .45 2.20 5.57 .813 369 1.51 2.96 < .01 779 1.98 .130 1,340

SQ1-0250 250 S FA 13.9 1.95 68.1 2.83 .65 .36 1.98 14.4 1.36 373 1.47 3.49 < .01 779 1.99 .129 1,410

SQ1-0428A 428 S FA 12.9 1.99 66.2 4.22 .66 .25 1.96 19.0 2.09 371 1.41 2.62 < .01 776 1.97 .128 1,620

SQ1-0428B 428 S FA 12.3 2.06 69.7 4.08 .68 .45 1.88 21.9 2.13 379 1.48 2.79 < .01 766 2.05 .129 1,680

SQ1-0525 525 S FA 12.7 2.04 68.8 4.09 .69 .44 2.11 18.8 1.87 369 1.48 2.96 .01 783 2.02 .127 1,620

SQ1-0625 625 LBI FA 25.6 2.21 65.1 3.48 .41 .49 2.16 132 4.38 230 1.29 7.09 .02 955 2.09 .126 1,690

SQ1-0681 672 LBI FA 13.2 4.38 130 < .09 .90 .58 .62 629 .160 642 1.11 .56 .02 1,300 2.51 .408 204

SQ1-0682 682 LBI FA 13.5 9.75 90.7 3.54 2.24 .69 1.09 1,390 .835 1,920 5.67 3.44 .02 1,630 1.88 .341 5,110

SQ1-0731 731 S FA 13.4 2.58 71.0 2.89 .51 .60 1.55 37.5 .948 302 1.45 2.54 < .01 839 2.01 .118 1,510

SQ1-0757 757 LBI FA 13.1 2.46 66.2 2.72 .42 .27 1.88 17.4 1.04 252 1.37 2.21 < .01 809 1.98 .119 1,390

SQ1-0770 770 LBI FA 13.4 1.96 443 1.42 .34 1.22 1.49 30.8 3.06 74.0 1.46 .62 .28 2,710 6.24 .764 352

SQ1-0861 861 S FA 3.98 2.28 48.7 .81 .27 .77 1.22 50.3 .501 184 1.18 1.56 .01 825 2.06 .145 932

SQ1-1050 1,050 RBI FA 13.2 7.50 113 .54 2.06 .52 1.63 96.5 .269 < 5 2.57 2.40 < .01 1,100 2.12 .782 757

SQ1-1095 1,095 S FA 14.8 2.80 78.4 2.89 .53 .37 1.64 35.6 1.32 328 1.44 2.54 .01 873 2.06 .116 1,560

SQ1-1148 1,148 RBI FA 37.5 3.43 73.3 9.66 .50 .59 5.59 160 17.2 309 1.50 2.37 .08 937 2.10 .231 2,160

SQ1-1229 1,229 S FA 13.5 3.13 54.3 .76 .53 .53 1.31 50.4 .539 419 1.33 1.80 .01 840 2.05 .156 1,010

SQ1-1235 1,235 RBI FA 14.9 .54 40.7 77.1 1.27 .54 9.52 18.2 .922 743 .37 13.0 .03 1,310 1.02 .028 25,500

SQ1-1300 1,300 S FA 13.2 2.65 77.3 4.88 .54 .41 2.05 17.6 2.03 337 1.81 2.63 .03 894 2.09 .120 1,950

SQ1-1309 1,309 RBI FA 12.9 3.10 56.1 .64 .55 .65 1.33 41.3 .714 419 1.36 1.91 < .01 853 2.13 .156 979

SQ1-1371A 1,371 S FA 11.6 2.80 68.2 3.45 .53 .21 2.06 27.2 1.85 367 1.37 2.28 <.01 876 2.07 .143 1,560

SQ1-1371B 1,371 S FA 11.9 2.48 68.6 3.40 .53 .25 2.05 24.6 1.67 369 1.39 2.34 .01 867 2.07 .136 1,570

SQ1-1452 1,452 S FA 13.8 2.66 70.9 3.33 .54 .36 3.06 18.3 1.61 378 1.42 2.52 < .01 886 2.14 .145 1,690

SQ2-1601 1,601 S FA 4.35 2.70 54.7 9.62 .76 .47 3.39 16.4 1.62 269 1.47 2.68 .01 714 2.01 .249 2,380

SQ1-1744 1,744 S FA 15.1 13.8 48.9 28.2 4.33 .68 4.37 362 .736 1,150 1.69 6.97 .03 1,250 2.29 .107 7,120

Middle injection reach

SQ2-1843A 1,843 S FA 3.45 2.83 56.0 12.7 .54 .31 3.66 12.6 2.35 220 1.53 2.78 .02 714 2.12 .271 2,440

SQ2-1843B 1,843 S FA 2.60 2.90 56.3 12.8 .63 .40 4.08 19.5 2.92 233 1.54 2.54 .03 735 2.08 .292 2,380

SQ2-1843C 1,843 S FA 2.59 2.90 55.8 12.9 .63 .37 4.04 22.2 3.10 234 1.50 2.62 .03 726 2.11 .283 2,380

SQ2-1959 1,959 S FA 1.65 2.93 130 < .09 .10 .23 .56 91.4 .510 241 .24 .44 < .01 258 .586 3.71 2,470

SQ2-1965 1,965 RBI FA 37,000 2.55 9.91 1014 318 10.5 959 34,400 892 23,600 .09 346 1.20 1,620 12.8 .944 270,000

SQ2-2048 2,048 S FA 35.1 1.41 49.8 22.0 2.52 .34 6.24 94.8 .941 308 1.41 5.10 .02 672 1.93 .147 4,350

SQ2-2118 2,118 RBI FA 4.79 2.64 56.9 13.0 .71 .42 4.32 16.2 2.71 36.3 1.49 2.94 .02 820 2.12 .284 26

SQ2-2171 2,171 S FA 25.6 1.83 58.3 18.8 2.24 .39 5.90 15.5 1.71 313 1.52 4.44 .01 752 2.23 .229 3,350

SQ2-2337 2,337 S FA 25.1 2.01 58.5 19.4 2.30 .35 6.80 28.5 4.34 305 1.61 5.01 .04 746 2.36 .237 3,380

SQ2-2431 2,447 LBI FA 1.78 8.99 145 19.7 .19 .41 8.59 6.00 3.12 48.3 3.37 1.43 .04 1,020 6.02 1.11 1,590

SQ2-2560 2,519 S FA 28.6 1.66 60.3 18.9 3.24 .32 6.78 21.2 1.76 300 1.66 6.56 .02 854 2.46 .236 3,360

SQ2-2569 2,528 RBI FA 26.2 2.10 44.7 73.7 14.2 .35 74.3 350 35.8 399 1.23 29.0 .08 1,370 2.14 .063 11,300

SQ2-2678 2,637 S FA 30.2 1.43 59.9 19.9 3.51 .37 6.59 21.2 1.42 309 1.64 5.87 .01 801 2.42 .217 3,470

SQ2-2718 2,677 RBI FA 8.48 3.14 48.2 40.1 8.66 .33 18.2 103 5.26 554 1.60 14.1 .06 1,270 4.98 .571 6,110
32 Principal Locations of Metal Loading from Flood-Plain Tailings, Lower Silver Creek, Utah, April 2004 Table 4. Concentration of trace elements in synoptic water samples collected along Silver Creek, Utah, April 2004—Continued. Sample identification Dis- tance Source Fil- ter Alumi- num Arse- nic Bari- um Cad- mium Co- balt Chro- mium Cop- per Iron Lead Manga- nese Molyb- denum Nickel Sil- ver Stron- tium Ura- nium Vana- dium Zinc SQ2-2730 2,757 S FA 31.2 1.61 57.7 21.1 3.65 .26 7.60 48.7 2.45 314 1.62 6.20 .04 737 2.35 .194 3,580 Middle injection reach—Continued SQ2-2785 2,847 S FA 29.9 1.58 61.3 21.5 3.69 .30 7.01 21.5 1.49 317 1.69 6.80 .02 819 2.56 .219 3,590 SQ2-2780 2,892 RBI FA 13.7 3.17 56.2 29.1 2.91 .28 7.25 28.2 1.60 305 1.70 6.32 .04 888 2.55 .240 4,690 SQ2-2810 2,927 S FA 28.2 1.59 59.7 21.4 3.60 .34 7.00 22.2 1.54 315 1.64 6.07 .02 831 2.48 .213 3,740 SQ2-3027 3,144 LBI FA 6.53 8.71 65.2 26.0 1.15 .29 9.10 25.6 3.10 152 1.74 4.01 .05 977 2.43 .306 3,320 SQ2-3045 3,162 RBI FA 8.20 4.67 53.7 32.2 2.63 .32 8.39 32.5 2.54 348 1.64 5.73 .05 965 2.57 .232 4,840 SQ2-3254A 3,371 S FA 21.6 1.95 54.9 23.2 3.56 .29 7.04 24.3 1.62 317 1.56 6.26 .04 715 2.33 .175 4,230 SQ2-3254B 3,371 S FA 26.0 1.85 59.9 22.6 3.68 .38 7.60 22.6 1.79 315 1.73 6.12 .02 861 2.46 .220 3,840 SQ2-3379 3,496 S FA 25.9 1.82 61.1 22.8 4.21 .38 7.31 28.6 1.77 329 2.10 7.45 .03 864 2.55 .210 3,960 SQ2-3598 3,715 RBI FA 15.1 2.08 89.1 155 36.3 .43 19.8 129 4.31 3,540 2.99 20.3 .28 2,030 3.22 .063 24,400 SQ2-3602 3,719 LBI FA 15.1 5.66 71.6 62.8 7.58 .35 16.8 125 13.7 658 1.72 12.5 .04 1,280 2.11 .209 11,300 SQ2-3784A 3,901 S FA 24.7 1.94 61.9 24.3 4.52 .38 7.73 21.8 1.62 341 1.71 7.58 .02 878 2.53 .213 4,150 SQ2-3784B 3,901 S FA 25.3 1.84 61.4 24.6 4.51 .41 7.75 23.2 1.70 346 1.69 7.65 .02 894 2.55 .216 4,200 SQ2-4000 4,117 RBI FA 9.85 4.37 58.8 26.7 3.77 .48 7.95 48.9 6.74 484 1.89 5.96 .05 982 2.60 .281 4,840 SQ2-4050 4,167 S FA 14.8 2.81 58.9 25.8 4.23 .29 8.21 21.9 2.73 373 1.77 6.96 .03 840 2.44 .232 4,390 SQ2-4286 4,403 S FA 14.3 2.82 60.5 25.7 4.03 .35 7.62 24.4 3.17 366 1.69 7.24 .03 913 2.59 .247 4,250 SQ2-4292 4,409 LBI FA 1.55 9.41 65.2 60.6 1.09 .66 16.1 17.8 13.5 258 2.81 7.78 .14 1,280 2.73 .127 8,400 SQ2-0054 4,517 LBI FA 2.16 18.2 113 23.4 .44 .32 7.81 12.6 4.74 160 1.83 2.99 .06 1,710 3.21 .333 2,600 SQ2-0061 4,800 S FA 13.3 3.31 63.0 26.3 4.02 .43 7.89 20.8 3.75 368 1.79 7.23 .03 967 2.67 .257 4,250 SQ2-0080 5,251 S FA 3.60 6.59 61.2 23.4 2.43 .24 12.5 19.0 2.85 271 1.98 6.19 .03 1,040 2.67 .270 3,450 SQ2-0096 5,493 RBI FA 3.53 6.77 50.4 38.4 5.75 .30 9.76 76.8 6.13 1,950 2.32 8.32 .02 1,510 2.62 .101 8,380 SQ2-0100 5,624 S FA 3.59 7.33 58.4 27.3 2.55 .86 8.03 33.8 4.12 506 2.02 5.23 .04 1,130 2.55 .244 4,460 SQ2-0108 5,833 RBI FA 2.25 6.70 23.0 4.74 1.47 .24 3.28 30.4 .574 619 1.15 3.10 .01 1,100 1.31 .035 3,440 SQ2-0109 5,843 RBI FA 2.34 3.47 26.3 188 6.00 .28 16.4 144 7.70 2,010 .85 21.2 .14 1,540 1.72 .035 53,400 SQ2-0149 5,878 RBI FA 337 16.5 33.4 2038 229 .42 33.5 1,910 104 10,900 2.15 281 .49 1,320 .068 .064 1,070,000 SQ2-0113 5,950 S FA 3.60 6.75 56.0 28.5 2.63 .49 7.90 24.3 3.00 552 1.92 5.98 .03 1,130 2.52 .221 5,140 SQ2-0120 6,045 RBI FA 9,520 20.3 34.8 562 278 2.62 304 63,000 539 9,860 .02 221 .06 2,340 1.45 .331 132,000 SQ2-0122 6,093 S FA 12.7 5.11 57.3 30.7 3.43 .41 8.77 65.1 3.31 597 1.96 7.33 .03 1,150 2.59 .209 5,600 SQ2-0135 6,322 S FA 10.5 4.55 56.4 31.8 3.50 .53 8.55 29.8 2.04 644 1.93 7.10 .02 1,150 2.57 .193 6,110 SQ2-0137 6,353 RBI FA 7.01 7.53 58.2 151 20.9 .27 24.5 58.8 4.61 4,080 2.08 26.7 .06 1,340 1.01 .094 45,300 SQ2-0005 7,120 S FA 11.9 4.30 58.0 34.5 3.76 .31 8.99 43.2 3.26 754 1.97 7.89 .05 1,180 2.65 .196 6,890 Lower injection reach SQ3-005 7,142 S FA 8.36 4.26 60.6 38.1 4.92 .19 10.2 17.9 2.83 952 2.26 8.62 .03 1,250 2.80 .184 6,800 SQ3-008 7,161 S FA 7.88 4.33 62.6 38.7 5.00 .24 10.3 18.5 3.02 945 2.29 8.69 .03 1,280 2.89 .184 6,800 SQ3-008 7,161 S RA 37.2 10.1 63.0 39.1 5.17 < .15 14.2 433 35.1 959 2.39 8.97 .30 1,220 2.94 .308 7,130 SQ3-010 7,185 RBI FA 2.52 2.71 92.2 183 3.47 .27 11.0 6.05 5.85 1,980 1.67 12.4 .07 2,100 2.87 .117 30,100

SQ3-010 7,185 RBI RA 15.3 4.31 91.5 190 3.51 .11 13.3 95.0 15.8 1,960 1.69 12.9 .38 1,940 2.89 .154 30,000

SQ3-012 7,208 S FA 8.07 4.54 62.8 37.0 4.95 .22 10.1 22.4 3.30 950 2.30 8.58 .03 1,330 2.93 .191 6,730

SQ3-018 7,276 S FA 7.79 4.55 61.8 38.9 4.82 .29 10.2 24.8 3.55 940 2.23 8.42 .02 1,250 2.90 .176 6,890

SQ3-024 7,365 RBI FA 2.15 5.15 69.7 117 2.13 .21 21.9 21.3 76.9 2,200 2.24 6.37 .35 1,370 .984 .029 26,300

SQ3-025 7,366 LBI FA 2.72 2.90 48.8 224 3.80 .28 20.3 7.63 15.1 1,040 .85 17.5 .09 2,630 1.78 .094 44,800

SQ3-032 7,397 S FA 7.10 4.45 60.1 38.0 4.69 .16 10.0 19.4 3.37 935 2.25 8.46 .02 1,300 2.81 .185 7,370

SQ3-032 7,397 S RA 33.8 9.92 62.4 41.0 4.91 .05 14.3 409 34.7 920 2.29 8.96 .30 1,190 2.93 .300 7,510
Table 4 33

Table 4. Concentration of trace elements in synoptic water samples collected along Silver Creek, Utah, April 2004—Continued.

Sample 

identification

Distance Source Fil- ter Alumi- num Arse- nic Bari- um Cad- mium Co- balt Chro- mium Cop- per Iron Lead Manga- nese Molyb- denum Nickel Sil- ver Stron- tium Ura- nium Vana- dium Zinc

SQ3-039 7,470 S FA 6.40 4.47 61.0 40.3 4.69 .22 10.7 18.9 3.57 952 2.25 8.38 .02 1,320 2.74 .187 7,930

Lower injection reach—Continued

SQ3-042 7,491 LBI FA 2.03 4.42 86.7 7.27 .27 .31 2.39 3.37 .840 144 1.91 6.15 .02 1,400 8.33 .981 8,740

SQ3-048 7,571 S FA 6.68 4.60 63.2 40.5 4.63 .25 10.8 18.6 3.78 932 2.25 8.54 .03 1,320 3.00 .206 7,880

SQ3-056 7,687 S FA 5.92 4.45 62.3 42.8 4.56 .24 11.1 16.8 3.75 944 2.23 8.98 .03 1,280 2.89 .199 8,420

SQ3-060 7,730 LBI FA 2.33 3.82 32.9 462 9.81 .32 478 6.34 100 6,200 3.97 36.5 .29 2,480 3.61 .036 117,000

SQ3-060 7,730 LBI RA 3.59 4.02 32.4 478 9.97 .19 508 17.1 103 6,200 3.95 38.5 .55 2,370 3.66 .039 117,000

SQ3-066 7,825 S FA 5.57 4.46 63.3 40.9 4.35 .20 11.0 14.3 3.82 902 2.31 8.52 .03 1,380 2.92 .199 8,420

SQ3-083 8,009 RBI FA 3.54 9.70 94.4 134 8.47 .24 15.5 111 33.2 3,970 3.69 7.72 .38 1,780 1.68 .089 25,200

SQ3-097 8,225 S FA 4.61 4.43 62.7 42.9 4.05 .19 11.2 17.0 4.49 884 2.30 8.54 .03 1,340 2.92 .201 8,420

SQ3-115 8,449 RBI FA 2.24 17.9 11.6 16.9 1.07 .38 1.37 116 1.17 636 1.05 1.89 .01 201 .236 < .01 9,150

SQ3-121 8,497 LBI FA 2.06 4.37 60.3 189 1.87 .20 13.5 12.5 18.0 1,540 1.98 10.3 .10 1,800 2.35 .085 46,000

SQ3-127 8,591 S FA 5.08 4.36 63.6 48.6 4.22 .24 12.6 24.2 7.89 885 2.30 8.78 .03 1,310 2.87 .179 9,280

SQ3-127 8,591 S RA 24.5 8.95 61.9 47.5 3.80 < .05 16.1 321 40.0 856 2.28 8.66 .27 1,240 2.90 .277 9,310SQ3-131 8,701 LBI FA 1.66 7.16 38.6 31.4 4.41 .23 8.56 17.5 13.9 3,050 4.07 6.51 .06 954 2.19 .083 14,800

SQ3-140 8,862 S FA 3.58 4.29 64.1 46.7 3.75 .26 12.4 14.5 7.73 936 2.33 8.45 .02 1,380 2.89 .190 9,040

SQ3-141 8,881 LBI FA 8.36 4.86 51.0 0.81 .33 .42 4.51 22.4 2.59 60.9 14.2 2.46 .03 782 1.49 .889 357

SQ3-142 8,886 RBI FA 1.67 9.24 34.8 1.35 .61 .20 2.87 24.9 .366 347 2.33 1.52 < .01 1,230 6.07 .258 765

SQ3-145 8,909 S FA 6.09 4.84 56.7 25.3 2.10 .29 8.81 14.2 2.79 518 7.26 5.70 .03 1,090 2.45 .550 4,370

SQ3-145 8,909 S RA 20.3 7.50 58.0 27.1 2.13 .13 12.0 206 31.1 535 7.30 5.73 .22 1,040 2.52 .625 5,390

SQ3-172 9,355 S FA 3.72 7.00 57.8 27.1 2.32 .30 9.00 8.63 2.60 675 5.97 6.00 .01 1,120 2.55 .460 5,100

SQ3-173 9,360 RBI FA 1.66 2.30 89.7 < .09 .65 .21 .48 22.7 .297 2,060 .83 .91 < .01 946 2.23 2.10 13

SQ3-178A 9,438 S FA 3.95 7.07 61.6 24.2 2.29 .27 8.15 9.44 2.55 757 5.76 5.61 .02 1,200 2.50 .606 5,890

SQ3-178A 9,438 S RA 66.4 11.8 64.2 28.0 2.37 .24 16.2 430 98.2 789 5.74 5.99 .38 1,070 2.60 .740 5,910

SQ3-178B 9,438 S FA 4.02 6.91 59.5 24.8 2.20 .25 8.20 22.4 2.73 754 5.67 5.53 .02 1,090 2.52 .588 4,800

SQ3-178B 9,438 S RA 3.57 4.88 67.4 51.6 3.84 .13 13.4 17.1 7.34 980 2.50 9.02 .05 1,360 2.96 .186 10,600

SQ3-186 9,562 LBI FA 1.76 10.3 114 < .09 .23 .25 .76 49.5 2.88 104 1.08 .50 < .01 341 1.77 3.51 178

SQ3-189 9,598 LBI FA 2.09 2.06 372 0.82 2.52 .23 6.04 44.9 .849 4,760 3.02 5.02 .02 2,760 9.11 .084 380

SQ3-193 9,719 S FA 3.01 8.08 66.2 21.3 2.01 .27 7.45 9.59 2.92 713 5.40 5.17 .02 1,000 2.48 .985 4,270

SQ3-193 9,719 S RA 77.8 14.1 68.5 24.7 2.13 .29 15.1 503 102 724 5.38 5.28 .38 960 2.51 1.25 5,260

SQ3-194 9,725 RBI FA 3.34 32.4 60.3 0.69 2.24 .33 1.16 366 3.15 4,390 7.09 1.83 < .01 381 1.61 .876 657

SQ3-196 9,747 S FA 3.42 8.35 66.5 19.2 2.01 .30 7.12 11.3 2.23 689 5.95 4.93 < .01 1,100 2.39 1.04 3,900

SQ3-196 9,747 S RA 66.5 13.4 66.8 22.9 1.95 .26 13.7 473 87.8 705 5.59 5.05 .35 932 2.43 1.24 5,070
34 Principal Locations of Metal Loading from Flood-Plain Tailings, Lower Silver Creek, Utah, April 2004

B.A. Kimball and others—Principal Locations of Metal Loading from Flood-Plain Tailings, Lower Silver Creek, Utah, April 2004—SIR 2007-5248