Use of Short-Term (5-Minute) and Long-Term (18-Hour)

Leaching Tests to Characterize, Fingerprint, and Rank

Mine-Waste Material from Historical Mines in the 

Deer Creek, Snake River, and Clear Creek Watersheds

in and around the Montezuma Mining District, Colorado

By Philip L. Hageman

U.S. Geological Survey Scientific Investigations Report 2004-5104

U.S. Department of the Interior

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

Gale A. Norton, Secretary

U.S. Geological Survey

Charles G. Groat, Director

Posted online July 2004

For more information about the USGS and its products:

Telephone: 1-888-ASK-USGS

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

This publication is only available online at:

http://pubs.usgs.gov/sir/2004/5104/
Contents

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

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

Purpose of Investigation..................................................................................................................... 2

Acknowledgments............................................................................................................................... 2

Montezuma Mine-Waste Piles: Geologic Perspective........................................................................... 2

Sampling Locations ...................................................................................................................................... 2

Sample Media ............................................................................................................................................... 4

Sample Collection......................................................................................................................................... 4

Leaching Parameters................................................................................................................................... 4

Analytical Methods and Procedures......................................................................................................... 5

pH ................................................................................................................................................... 5

Specific Conductance......................................................................................................................... 5

Metals Analyses .................................................................................................................................. 5

NAP Analyses....................................................................................................................................... 5

Sulfate Analyses .................................................................................................................................. 5

Mercury Analyses ............................................................................................................................... 5

Results and Discussion................................................................................................................................ 5

Data ................................................................................................................................................... 5

Leachate Geochemical Comparisons and Trends for All Sites........................................... 5

pH and Specific Conductance......................................................................................... 6

Sulfate ................................................................................................................................. 6

Geochemical Data for Individual Sites.................................................................................... 7

Mine-Waste Rankings.................................................................................................................................. 7

Conclusions ................................................................................................................................................. 21

References................................................................................................................................................... 23

Appendix 1—Leachate Geochemical Data from 5-Minute and 18-Hour Leaches of 

13 Mine-Waste Composite Samples Included in this Study .................................................. 24

Appendix 2—Net-Acid Production for 13 Mine-Waste Composite Samples 

Included in this Study ................................................................................................................... 27

Appendix 3—Mine-Waste Geochemistry Highlights............................................................................ 28

Figures

1. Location map for 13 mine dumps sampled for this study....................................................... 3

2. Comparison of leachate pH and specific conductance data for 

13 mine-wastes included in this study...................................................................................... 6

3. Comparison of leachate sulfate data for 13 mine-wastes included in this study.............. 7

iii
4.–16. Mine-waste leachate geochemistry trends for selected major elements, 

selected trace metals, pH, and specific conductance for:

4. Arabella mine ..................................................................................................................... 8

5. Lower Radical mine........................................................................................................... 9

6. Lower Chatauqua mine................................................................................................... 10

7. General Teller mine.......................................................................................................... 11

8. Cashier mine..................................................................................................................... 12

9. Togo mine .......................................................................................................................... 13

10. Burke mine........................................................................................................................ 14

11. Superior mine ................................................................................................................... 15

12. Wild Irishman mine.......................................................................................................... 16

13. Grizzly mine....................................................................................................................... 17

14. Jack Pine mine................................................................................................................. 18

15. Waldorf mine .................................................................................................................... 19

16. Santiago mine................................................................................................................... 20

Tables

1. Mine-wastes sampled, their location, and host-rock formation .......................................... 4

2. Mine-waste rankings for potential effects of runoff due to an event 

such as a thunderstorm for 13 mine-wastes sampled ......................................................... 21

3. Mine-waste rankings for potential effects of runoff due to 

an extended leaching event (18-hour leach test) for 13 mine-wastes sampled.............. 22

4. Mine-waste rankings for net-acid production ...................................................................... 22

A1. Leachate geochemical data from 5-minute and 18-hour leaches of 

13 mine-waste composites included in this study ................................................................ 24

A2. Net-acid production for 13 mine-waste composite samples included in this study....... 27

iv
Abstract

Precipitation-induced runoff from historical mine-waste 

located adjacent to the headwaters of the Snake River, Deer 

Creek, Saints John Creek, Grizzly Gulch, Stevens Gulch, and 

Leavenworth Creek contributes to the degradation of water 

quality in these streams. Because historical mine-waste piles 

have had long-term exposure to the atmosphere, it is surmised 

that runoff from these piles, induced by meteorological events 

such as cloudbursts and snowmelt, may cause mobility of acid 

and metals into a watershed due to dissolution of soluble minerals. For this study, 13 mine-waste composite samples from 

various mine-wastes in these drainage basins were leached 

using both a short-term and a long-term leach test. Analytical 

results from this combination of leach tests are tools that allow 

the investigator to quantify (fingerprint) which geochemical components could be expected in runoff from these piles 

if they were leached by a cloudburst (5-minute leach test), 

as well as what the “worst-case” geochemical profile would 

look like if the material were subject to extended leaching and 

breakdown of the mine-waste material (18-hour leach test). 

Also, this combination of leach tests allows the geoscientist 

the ability to see geochemical changes in the mine-waste 

leachate over time. That is, does the leachate become more or 

less acidic over time; does the specific conductance increase or 

decrease; and are there changes in the concentrations of major 

or trace elements? Further, use of a ranking scheme described 

herein will aid in prediction of which historical mine-waste 

piles have the greatest potential for impact on a watershed 

should runoff occur.

Because of long-term weathering of these historical 

mine-waste piles, geochemical profiles, leachate time-trends, 

and relative ranking of the mine-wastes produced from analysis of the leachates are indicative of how the mine-waste piles 

can be expected to act in the environment and may help to 

identify the “bad actors”—this may aid in understanding the 

reasons for water-quality differences between the drainages. 

Introduction

Over time, extensive effort has been made in and around 

the Montezuma mining district to fully understand the relationship of geology, hydrology, geochemistry, and mineralogy to 

the environmental impacts observed in watersheds in these 

areas. Historical mine-wastes are known to be primary point 

sources for stream-water degradation, and it has been demonstrated that the water quality of the Snake River watershed is 

impacted by upstream geochemical processes in its headwaters 

(Munroe, 2000). However, in this study area, distinct streamwater characteristics are seen in adjacent drainage basins that 

are close to each other spatially but have very different streamwater chemistry and water quality. Examples of these differences in stream-water chemistry for several of the tributaries of 

the Snake River in the Montezuma mining district are detailed 

in Fey and others (2002). Although some of the differences in 

stream-water quality are due to the geologic complexities of 

these basins, input from mine-adit drainage and runoff from 

mine-waste piles play a significant ongoing role in streamwater chemistry and quality. These impacts vary depending on 

the geologic characteristics of the mine-waste material being 

leached, as is explained in Plumlee and others (1995). 

To further aid in the understanding of point-source inputs 

from various historical mine-wastes in these basins, this study 

provides leachate geochemical data, or geochemical “fingerprints,” of historical mine-waste samples collected from 13 historical mine-wastes in a few of these tributary watersheds. Geochemical data were compared to see if significant geochemical 

differences in leachate chemistry exist in the mine-waste material from the side-by-side drainages. Comparison of leachate 

geochemical profiles from mines in these drainage basins helps 

to explain the reasons for water-quality differences that exist in 

the streams. Data from this study were also used to profile the 

probable runoff characteristics of the mine-waste piles (how 

acidic the runoff would be and what metals could be expected 

to be mobilized). Geochemical profiling and understanding 

Use of Short-Term (5-Minute) and Long-Term (18-Hour) 

Leaching Tests to Characterize, Fingerprint, and Rank 

Mine-Waste Material from Historical Mines in the 

Deer Creek, Snake River, and Clear Creek Watersheds 

in and around the Montezuma Mining District, Colorado

By Philip L. Hageman

1
probable runoff characteristics is important because flushing of 

well-weathered mine-waste material by rain or snow can have 

significant impact as a point source of water-quality degradation due to the migration of acid, metals, and fluvial tailings 

into the watershed. In addition, this paper provides a way to 

rank the sites according to their geochemical profile. This ranking scheme can be used to predict which mine-wastes have the 

potential for greatest impact on stream-water quality.

Purpose of Investigation

The purpose of this investigation is threefold: First, this 

report provides other investigators two sets of leachate geochemical data (5-minute leach test and 18-hour leach test) for 

solid mine-waste composite samples collected from 13 different historical mine-waste sites in the Montezuma mining 

district and surrounding basins. Leachate data can be used to 

produce unique geochemical fingerprints for these sites. Further, these data will allow investigators to visualize how runoff 

from specific piles may impact water resources in these basins. 

The second purpose of this study was to use leachate geochemical data from this investigation for a comparative study 

as part of a larger effort to see whether differences can be seen 

in the geochemical characteristics and time trends of the minewaste leachates from the various basins. Specifically, observations and data were compiled and compared to see if changes 

in leachate pH, specific conductance, and metal concentrations 

change over time from the 5-minute leach to the 18-hour leach 

in order to see whether these trends reveal potential reasons 

for water-quality differences in streams draining these basins. 

Net-acid production (NAP) (Lapakko and Lawrence, 1993) 

was performed on a split of the solid portion of all 13 minewaste samples in order to determine if a correlation can be 

made between NAP and other geochemical data produced by 

leaching. Thirdly, after compiling and analyzing the leachate 

geochemical data from all the sites, this investigation presents 

a ranking scheme for use in predicting which historical minewaste piles have the greatest potential for negative impact as a 

point source of acid and metals into a watershed. 

Acknowledgments

I thank Dana Bove for insight and interpretation of the 

geology for this study and Greg Lee for help with GIS applications.

Montezuma Mine-Waste Piles: 

Geologic Perspective

The mine-wastes included in this study represent workings from mesothermal, fissure-filling lead-zinc-silver vein 

deposits (Lovering, 1938). Galena, sphalerite, pyrite, and 

quartz are present in most of the veins in the Montezuma 

mining district and surrounding area and are much more 

abundant than other vein-related minerals. Copper sulfides are 

the most abundant of the minor constituents of these ores and 

were found in most of the vein deposits. Silver, when present in these veins, was generally associated with chalcopyrite 

and tetrahedrite-tennantite (Lovering, 1935); however, most 

of the silver in the ores formed as discreet minerals, typically as silver sulfantimonides or sulfarsenides. Quartz is the 

dominant gangue mineral associated with the Montezuma 

vein deposits. Ankerite and barite are also common. Ankerite, 

when present, is reported to contain variable amounts of manganese, iron, and magnesium and weathers black due to high 

manganese content (Lovering, 1938). Although ankerite is 

reported in relative abundance in a number of the Montezuma 

mines (including the Lower Chautauqua, Wild Irishman, and 

Santiago), when present in mine-waste material, its abundance 

was probably on the order of 1 percent or less (D. Bove, written commun., 2003). Overall, vein deposits of the Montezuma 

and surrounding areas are typical of polymetallic vein deposits 

hosted in noncarbonate rocks, as summarized by Plumlee and 

others (1995) in a compendium on the geoenvironmental signatures of ore deposits (du Bray, 1995). 

Mines west of the upper Snake River drainage basin—

i.e., Deer Creek and Sts. John drainage basins—are hosted in 

hornblende gneiss or amphibolites (Lovering, 1938). Rocks 

west of the upper Snake River basin are generally unaltered 

and lacking in pervasive pyritization except locally around 

vein deposits (D. Bove, written commun., 2003). In contrast, 

rocks in the eastern part of the upper Snake River basin are 

dominantly biotite-quartz-sillimanite schist and gneisses that 

have been strongly affected by hydrothermal alteration related 

to Tertiary-age intrusions (Neubert and others, 2004). The 

most intense alteration and pyritization is focused in the Webster Pass and Handcart Gulch areas. 

Clinochlore is present in many of the metamorphic rocks 

in the Montezuma area and also formed as a replacement of 

biotite and other iron-magnesium silicates during hydrothermal 

alteration. Calcite is rarely observed in lithologies of this area, 

but has been observed along faults and fractures in the hornblende gneisses and amphibolites (D. Bove, written commun., 

2003). Although rare, it is also reported in late supergene veinlets that cut vein ores not far from the ground surface, and in 

late-stage hypogene veinlets and vugs (Lovering, 1938). 

Sampling Locations

In the summers of 2001 and 2002, 13 mine-waste composite samples were collected from a variety of historical 

mine-wastes located in and around the Montezuma mining 

district in Colorado. Many of these mine-wastes are identified in Wilson and LaRock (1992) and Munroe (2000). Locations of mine-wastes sampled for this study are identified 

2 Leaching Tests to Characterize Mine-Waste Material from Historical Mines, Montezuma Mining District, Colo.
Figure 1. Location map for 13 mine dumps sampled for this study.

Sampling Locations 3
in figure 1. Specific information about each site—including 

the mine name, drainage basin in which the mine-wastes are 

located, and the host rock in which the mines reside—is given 

in table 1.

Sample Media

For this study, focus was applied to the leachate geochemical profile of the outer “skin” or upper 15 cm of the 

surface of the mine-waste pile. It is important to characterize 

the geochemical potential of the outer skin of mine-waste piles 

because the skin of a mine-waste pile is very geochemically 

reactive. This reactivity is due to contact with the atmosphere. 

In the case of these historical mine-waste piles, the outer surface of the piles have been exposed to atmospheric oxygen and 

severe weathering for extended periods of time. Weathering 

processes include wide temperature fluctuations, innumerable freeze/thaw cycles, high winds, solar influences, biologic 

activity, and precipitation in all forms. As a result of these factors, wet/dry cycles cause repeated leaching, that, in turn, produce continuous wicking, rinsing, and reformation of soluble 

mineral salts and other secondary minerals. At the same time, 

the body of the pile acts as a huge sulfide reservoir, providing 

acid and metals to replenish material leached from the surface.

Sample Collection

Mine-wastes were sampled using a composite sampling 

technique (Smith and others, 2000). The sampling procedure 

consisted of collecting at least 30 random samples from a 

mine-waste pile using a steel trowel and a plastic bucket. 

Coarse material (material that was larger than the top knuckle 

of the thumb) was discarded during collection. All increments were put into a 5-gallon plastic bucket and mixed. If the 

sample was wet, it was first air-dried on a plastic tarp and then 

mixed. The mine-waste composite was then sieved to pass a 

2-mm stainless steel screen. The <2-mm fraction was saved 

for leaching and further analysis, and all material >2 mm was 

discarded.

Leaching Parameters

The <2-mm mine-waste composite samples were leached 

using the simplified USGS field leach test described in Hageman and Briggs (2000), followed by an 18-hour end-over-end 

leaching test. In the USGS field leach test, 100.0 g of the <2-

mm fraction of the composite sample was put in a plastic bottle 

and 2.0 L of deionized water was slowly added. The container 

was capped and shaken vigorously for 5 minutes. After shaking, 

the mixture was allowed to settle for ~10 minutes. Leachates 

produced from these tests were measured for pH and specific 

conductance and then syringe-filtered (0.45-μm pore-size nitrocellulose capsule filters). Portions of the filtrate were taken and 

preserved for analysis by inductively coupled plasma–atomic 

emission spectroscopy, inductively coupled plasma–mass spectroscopy, ion chromatography, and for mercury analysis. The 

containers were then recapped and placed on an end-over-end 

rotator for 18 hours. After rotation for 18 hours, the leachates 

were allowed to settle. The leachate was then sampled, measured, and preserved in the manner described above.

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4 Leaching Tests to Characterize Mine-Waste Material from Historical Mines, Montezuma Mining District, Colo.
Analytical Methods and Procedures

Similar analytical methods and procedures were used for 

all samples. Following is a brief explanation of analytical techniques and equipment used in this study.

pH

Laboratory pH measurements for unfiltered leachates 

were obtained using an Orion Model 230-A pH meter and an 

Orion combination pH electrode. The meter was calibrated 

prior to each set of measurements, and calibration checks were 

obtained on mid-range buffers between readings. For calibration to be successful, buffers must not exceed known concentration by ±0.02 pH units. The analysis of pH required no 

sample treatment, and the sample was analyzed immediately. 

Specific Conductance

Laboratory measurements were made on unfiltered leachate using a Myron L portable conductivity meter (Model 

DC4). Prior to initial use, the meter was calibrated with commercially obtained conductivity standards. Prior to each set of 

observations, aliquots of commercially obtained 100-μS/cm 

and 1,000-μS/cm standards were checked and their values 

recorded. Conductivity analysis required no sample treatment, 

and samples were analyzed immediately.

Metals Analyses

Concentrations of metals were determined by the following methods: inductively coupled plasma–atomic emission 

spectroscopy (ICP-AES) (Meier and others, 1994), and inductively coupled plasma–mass spectroscopy (ICP-MS) (Lamothe 

and others, 1999). Preservation of the samples for metals 

analysis required that the sample be filtered and acidified to 

pH ≤1.5 with Ultrex II ultrapure HNO3 . Maximum hold time 

for the sample was 180 days.

NAP Analyses

NAP (net-acid production), sometimes referred to as 

“net-acidity,” was determined for all 13 mine-waste composites using a modification of the technique described by 

Lapakko and Lawrence (1993). This procedure is carried out 

on 1.00-g split of finely ground (–200 mesh) material taken 

from each <2-mm mine-waste composite sample. Results are 

given in kg CaCO3 per metric ton (parts per thousand). 

Sulfate Analyses

Sulfate was determined by ICP-MS (Lamothe and others, 

1999). This method required that the sample be filtered and 

acidified with HNO3 as described above. Maximum hold time 

was 180 days. 

Mercury Analyses

Leachate mercury concentrations were determined by 

cold vapor–atomic fluorescence spectrometry (CV-AFS) 

(Hageman, 2002). For this method, the filtrate was acidified/

preserved with a 1-percent sodium dichromate/concentrated 

HNO3 solution in a ratio of 1:19 (one part sodium dichromate/

HNO3 solution to 19 parts leachate sample). Leachate samples 

were collected in nitric-acid-washed flint-glass bottles with 

Teflon-lined lids.

Results and Discussion

In this report, leachate geochemical comparisons are 

made (5-minute USGS field leach test vs. 18-hour leach test) 

for all 13 mine-waste composite samples. Complete leachate 

geochemical data for all sites are given in tabular form in 

Appendix 1. NAP results for solid mine-waste samples are 

given in Appendix 2. Data plots comparing leachate pH, specific 

conductance, and sulfate for all 13 mine-wastes are presented 

(figs. 2 and 3) and discussed. In addition to comparing relative 

trends for all sites, plots detailing leachate geochemical data and 

trends for individual mine-wastes are presented in figures 4–16. 

Leachate geochemical summaries for individual mine-wastes 

are presented in Appendix 3. Data in the summaries include: site 

location, host rock, leachate pH, specific-conductance trends, , 

sulfate, selected major-element trends, selected trace-element 

trends, and NAP on the solids. Finally, this paper presents, 

describes, and discusses three mine-waste-ranking schemes. 

Data

Important note.—Concentrations presented in this paper 

are leachate concentrations. All samples were leached at 20:1 

ratio (20 parts deionized water to 1 part solid), except for NAP, 

which was measured from a split of the mine-waste composite 

<2-mm solid material.

Leachate Geochemical Comparisons and 

Trends for All Sites

Following is a brief summary comparing selected leachate geochemistry for all 13 sites. 

Results and Discussion 5
pH and Specific Conductance

Figure 2 shows the data and trend lines for all 13 minewaste leachate samples for pH and specific conductance over 

time. In this plot, pH data from the 5-minute USGS field 

leach test are compared to pH data from the 18-hour leach 

test. Leachate pH values went down over time in leachate 

produced from the Togo, Arabella, Lower Radical, and Jack 

Pine mine-waste composites. The lowest pH (3.0) was found 

in leachate from the Togo mine-waste (located in the upper 

Snake River watershed). However, the greatest drop in pH 

over time occurred in the leachate from the Lower Radical 

mine-waste (upper Deer Creek watershed), which dropped 

from pH 4.8 in the 5-minute leachate to pH 4.6 after 18 hours 

(–0.2 pH units). Other mine-waste leachates that dropped in 

pH over time were: Togo (–0.1), Arabella (–0.1), and the Jack 

Pine (–0.1). The largest increase in pH occurred in leachate 

from the Santiago mine-waste composite (Leavenworth Creek 

watershed), which showed a spike in pH from 3.6 after 5 minutes to 5.2 after 18 hours (+1.6 pH units). pH also increased 

over time in leachate from the Wild Irishman (+1.1), Lower 

Chatauqua (+0.4), Superior and Cashier (+0.3), Waldorf 

(+0.2), and the Burke and General Teller (+0.1). The pH in 

leachate from the Grizzly mine-waste stayed the same over 

time. 

pH trends produced from the 5-minute leach test correlated to pH trends produced from the 18-hour leach test. 

Figure 2 also shows specific conductance data and trends 

for all 13 mine-waste composites. 18-hour leachate values 

for specific conductance ranged from 8.78 μS/cm in the General Teller leachate (located in Upper Deer Creek watershed) 

to 1,730 μS/cm for leachate from the Santiago mine-waste 

(located in the Leavenworth Creek/Clear Creek watershed). 

Other leachates with high specific conductance were the Waldorf (located in the Leavenworth Creek/Clear Creek watershed) (1,092 μS/cm), and the Togo (718 μS/cm) (located in the 

Upper Snake River watershed).

Generally, the leachate specific conductance trend line for 

the 13 leachates corresponded very well to the trend for pH. 

That is, leachate samples with higher pH had lower specific 

conductivities and leachates with lower pH values had higher 

conductivities. Also, the relatively simple 5-minute test does a 

good job portraying the general trend for specific conductance 

for these 13 sites.

Sulfate

Figure 3 shows the 5-minute and 18-hour leachate sulfate 

concentration, and the sulfate trend for all 13 sites. Sulfate 

concentration was generally low (<200 mg/L) at 11 of the 13 

sites. However, the Waldorf and Santiago mine-wastes, located 

in the Leavenworth Creek/Clear Creek watershed, had much 

higher sulfate concentration, with 443 mg/L in the 5-minute 

Waldorf leachate and 736 mg/L sulfate in the 5-minute Santiago leachate.

Like many of the other geochemical data, sulfate data 

Leachate pH and Specific Conductance (5-minute vs 18-hour)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

Arabella

Lower Radical

Grizzly

Jack Pine

Togo

Lower Chatauqua

Cashier

Burke

Superior

General Teller

Wild Irishman

Waldorf

Santiago

pH (Standard Units)

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Specific Conductance (μS/cm)

pH 5 minute pH 18 hour Conductivity 5 minute Conductivity 18 hour

Figure 2. Comparison of leachate pH and specific conductance data (5 minute and 18 hour) for 13 mine-wastes 

included in this study.

6 Leaching Tests to Characterize Mine-Waste Material from Historical Mines, Montezuma Mining District, Colo.
produced using the simple 5-minute USGS field leach test 

gives an accurate indication for the sulfate trend produced 

after 18 hours. This comparison indicates that leachate sulfate 

trends are fairly predictable and that none of the samples fell 

out of line or changed much during the extended leaching 

period. There was not much change in sulfate concentration in 

the leachate over time. 

Geochemical Data for Individual Sites 

In figures 4–16, plots are presented for selected leachate geochemical data for each site. Each figure has three plots 

comparing leachate geochemistry for both the 5-minute and 

18-hour leaches. Data presented includes: A, selected major 

elements; B, selected trace metals; and C, pH, and specific 

conductance. The plots provide a visual depiction of the data 

so that geochemical trends are more easily seen.

Mine-Waste Rankings

The following tables show the relative ranking of all 

mine-wastes included in this study. These rankings were established after compiling and analyzing the leachate geochemical 

data. This simple ranking scheme was devised in order to rank 

each mine-waste relative to one another, for their potential to 

release acid, certain metals, and other constituents into the 

Leachate Sulfate Concentration for Thirteen Mine Dumps: 5-Minute vs 18-Hour

0

200

400

600

800

1000

1200

Arabella

Lower Radical

Grizzley

Jack Pine

Togo

Lower Chatauqua

Cashier

Burke

Superior

General Teller

Wild Irishman

Waldorf

Santiago

Sulfate (ppm)

Sulfate (5 min) Sulfate (18 Hr)

Figure 3. Comparison of leachate sulfate data (5 minute and 18 hour) for 13 mine-wastes included in this study.

environment should runoff occur from the mine-waste pile. 

Although many factors go into making a mine-waste leachate potentially toxic to the environment, for the purposes of 

this investigation, I used what I consider major contributing 

factors for potential toxicity. These factors are leachate pH, 

leachate conductivity, leachate sulfate, and, finally, the sum 

of concentrations of selected leachate metals (Al, Cd, Cu, Fe, 

Mn, Ni, Pb, and Zn). For this ranking procedure, each minewaste leachate was ranked for each of these four parameters. 

Each site was given a rank ranging from 1 to 13 (13 is the total 

number of sites included in this study) for each factor listed 

above. A rank of 1 represents the worst site (most impacted) 

for that particular factor, whereas a rank of 13 represents the 

least impacted site for that factor. As an example, a minewaste-producing leachate with the lowest pH of all 13 sites 

would get a ranking of “1.” If the same mine-waste leachate 

were 5th highest in leachate conductivity, it would receive a 

“5“ for that parameter. The same leachate would be ranked for 

sulfate and sum of metals (listed above). Cumulative results 

from all these tests would then be totaled. After all sites are 

tallied in this manner, the totals for all sites are ranked. The 

mine-waste leachate with the lowest cumulative score would 

then be ranked first in the probability that, should runoff occur, 

its effluent would have the most likely possibility of negatively 

affecting water quality should its effluent reach a water body. 

All other sites are ranked accordingly. 

Text continues on page 21

Results and Discussion 7
0

0.5

1

1.5

2

2.5

Ca Mg Na Si

Major Elements (

mg/L)

Arabella (5 min) Arabella (18 hr)

0

100

200

300

400

500

600

700

800

900

1000

Al Cd Co Cr Cu Fe Mn Ni Pb Zn

Trace Metals (μg/L )

Arabella Mine (5 min) Arabella Mine (18 hr)

4.3

4.3

4.3

4.4

4.4

4.4

4.4

4.4

4.5

5 minutes 18 hours

pH (Standard Units)

0

10

20

30

40

50

60

Specific Conductance

(μS/cm)

pH Conductivity

Figure 4. Arabella mine-waste leachate geochemistry trends (5 minutes vs. 18 hours) for A. 

selected major elements (ICP-AES); B, selected trace metals (ICP-MS); and C, pH and specific conductance.

A

B

C

8 Leaching Tests to Characterize Mine-Waste Material from Historical Mines, Montezuma Mining District, Colo.
0

0.5

1

1.5

2

2.5

3

3.5

Ca Mg Na Si

Major Elements (mg/L)

Low er Radical (5 min) Low er Radical (18 hr)

0

500

1000

1500

2000

2500

3000

Al Cd Co Cr Cu Fe Mn Ni Pb Zn

Trace Metals (μg/L)

Low er Radical Mine (5 min) Low er Radical Mine (18 hr)

4.5

4.6

4.6

4.7

4.7

4.8

4.8

4.9

5 minutes 18 hours

pH (Standard Units)

0

10

20

30

40

50

Specific Conductance

(μS/cm)

pH Conductivity

Figure 5. Lower Radical mine-waste leachate geochemistry trends (5 minutes vs. 18 hours) for 

A, selected major elements (ICP-AES); B, selected trace metals (ICP-MS); and C, pH and specific 

conductance.

A

B

C

Results and Discussion 9
0

2

4

6

8

10

12

14

16

Ca Mg Na Si

Major Elements (mg/L)

Lower Chatauqua (5 min) Lower Chatauqua (18 hr)

0

1000

2000

3000

4000

5000

6000

7000

Al Cd Co Cr Cu Fe Mn Ni Pb Zn

Trace Metals (μg/L)

Lower Chatauqua Mine (5 min) Lower Chatauqua Mine (18 hr)

4.8

4.9

5.0

5.1

5.2

5.3

5.4

5.5

5 minutes 18 hours

pH (Standard Units)

0

50

100

150

200

Specific Conductance

(μS/cm)

pH Conductivity

A

B

C

Figure 6. Lower Chatauqua mine-waste leachate geochemistry trends (5 minutes vs. 18 hours) for A. 

selected major elements (ICP-AES); B, selected trace metals (ICP-MS); and C, pH and specific conductance.

10 Leaching Tests to Characterize Mine-Waste Material from Historical Mines, Montezuma Mining District, Colo.
0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

Ca Mg Na Si

Major Elements (mg/L)

General Teller (5 min) General Teller (18 hr)

0

50

100

150

200

250

Al Ba Cd Co Cr Cu Fe Mn Ni Pb Zn

Trace Metals (μg/L)

General Teller Mine (5 min) General Teller Mine (18 Hr)

5.4

5.5

5.5

5.5

5.5

5.5

5.6

5.6

5 minutes 18 hours

pH (Standard Units)

0

2

4

6

8

10

Specific Conductance

(μS/cm)

pH Conductivity

A

B

C

Figure 7. General Teller mine-waste leachate geochemistry trends (5 minutes vs. 18 hours) for A. 

selected major elements (ICP-AES); B, selected trace metals (ICP-MS); and C, pH and specific conductance.

Results and Discussion 11
0

2

4

6

8

10

12

14

16

Ca Mg Na Si

Major Elements (mg/L)

Cashier (5 min) Cashier (18 hr)

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

Al Cd Co Cr Cu Fe Mn Ni Pb Zn

Trace Metals (μg/L)

Cashier Mine (5 min) Cashier mine (18 hr)

4.5

4.6

4.7

4.8

4.9

5.0

5.1

5 minutes 18 hours

pH (Standard Units)

0

50

100

150

200

250

Specific Conductance

(μS/cm)

pH Conductivity

Figure 8. Cashier mine-waste leachate geochemistry trends (5 minutes vs. 18 hours) for A. 

selected major elements (ICP-AES); B, selected trace metals (ICP-MS); and C, pH and specific 

conductance.

A

B

C

12 Leaching Tests to Characterize Mine-Waste Material from Historical Mines, Montezuma Mining District, Colo.
0

0.5

1

1.5

2

2.5

3

3.5

Ca Mg Na Si

Major Elements (mg/L)

Togo (5 min) Togo (18 hr)

0.1

1

10

100

1000

10000

100000

Al Ba Cd Co Cr Cu Fe Mn Ni Pb Zn

log of Trace Metal

Concentration (μg/L)

Togo (5 min) Togo (18 Hr)

2.8

2.8

2.9

2.9

3.0

3.0

5 minutes 18 hours

pH (Standard Units)

0

200

400

600

800

Specific Conductance

(μS/cm)

pH Conductivity

A

B

C

Figure 9. Togo mine-waste leachate geochemistry trends (5 minutes vs. 18 hours) for A. selected 

major elements (ICP-AES); B, selected trace metals (ICP-MS); and C, pH and specific conductance .

Results and Discussion 13
0

0.5

1

1.5

2

2.5

Ca Mg Na Si

Major Elements (mg/L)

Burke (5 min) Burke (18 hr)

0

100

200

300

400

500

600

Al Ba Cd Co Cr Cu Fe Mn Ni Pb Zn

Trace Metals (μg/L)

Burke Tunnel Mine FLT Burke Tunnel Mine 18 Hour

5.0

5.0

5.0

5.0

5.0

5.1

5.1

5.1

5 minutes 18 hours

pH (Standard Units)

0

2

4

6

8

10

12

14

Specific Conductance

(μS/cm)

pH Conductivity

Figure 10. Burke mine-waste leachate geochemistry trends (5 minutes vs. 18 hours) for A. 

selected major elements (ICP-AES); B, selected trace metals (ICP-MS); and C, pH and specific 

conductance .

A

B

C

14 Leaching Tests to Characterize Mine-Waste Material from Historical Mines, Montezuma Mining District, Colo.
0

1

2

3

4

5

Ca Mg Na Si

Major Elements (mg/L)

Superior (5 min) Superior (18 hr)

0

200

400

600

800

1000

1200

1400

1600

Al Ba Cd Co Cr Cu Fe Mn Ni Pb Zn

Trace Metals (μg/L)

Superior Mine (5 min) Superior Mine (18 Hr)

4.9

5.1

5.3

5.5

5 minutes 18 hours

pH (Standard Units)

0

10

20

30

40

50

60

70

Specific

Conductance

(μS/cm)

pH Conductivity

A

B

C

Figure 11. Superior mine-waste leachate geochemistry trends (5 minutes vs. 18 hours) for A. 

selected major elements (ICP-AES); B, selected trace metals (ICP-MS); and C, pH and specific conductance .

Results and Discussion 15
0

2

4

6

8

10

12

14

Ca Mg Na Si

Major Elements (mg/L)

Wild Irishman (5 min) Wild Irishman (18 hr)

0

100

200

300

400

500

600

700

Al Ba Cd Co Cr Cu Fe Mn Ni Pb Zn

Trace Metals (μg/L)

Wild Irishman Mine (5 min) Wild Irishman Mine (18 Hr)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

5 minutes 18 hours

pH (Standard Units)

0

20

40

60

80

100

120

Specific Conductance

(μS/cm)

pH Conductivity

Figure 12. Wild Irishman mine-waste leachate geochemistry trends (5 minutes vs. 18 hours) for 

A. selected major elements (ICP-AES); B, selected trace metals (ICP-MS); and C, pH and specific 

conductance .

A

B

C

16 Leaching Tests to Characterize Mine-Waste Material from Historical Mines, Montezuma Mining District, Colo.
0

1

2

3

4

5

6

7

8

Ca Mg Na Si

Major Elements (mg/L)

Grizzly (5 min) Grizzly (18 Hr)

0

50

100

150

200

250

300

350

400

Al Ba Cd Co Cr Cu Fe Mn Ni Pb Zn

Trace Metals (μg/L)

Grizzly Mine (5 min) Grizzly Mine (18 Hr)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

5 minutes 18 hours

pH (Standard Units)

0

10

20

30

40

50

60

70

80

Specific Conductance

(μS/cm)

pH Conductivity

Figure 13. Grizzly mine-waste leachate geochemistry trends (5 minutes vs. 18 hours) for A. 

selected major elements (ICP-AES); B, selected trace metals (ICP-MS); and C, pH and specific 

conductance .

A

B

C

Results and Discussion 17
0

2

4

6

8

10

12

14

16

Ca Mg Na Si

Major Elements (mg/L)

Jack Pine (5 min) Jack Pine (18 hr)

1

10

100

1000

10000

100000

Al Ba Cd Co Cr Cu Fe Mn Ni Pb Zn log of Trace Metal Concentration (μg/L)

Jack Pine Mine (5 min) Jack Pine Mine (18 Hr)

5.0

5.0

5.1

5.1

5.2

5 minutes 18 hours

pH (Standard Units)

0

50

100

150

200

250

300

Specific

Conductance

(μS/cm)

pH Conductivity

Figure 14. Jack Pine mine-waste leachate geochemistry trends (5 minutes vs. 18 hours) for A. selected 

major elements (ICP-AES); B, selected trace metals (ICP-MS); and C, pH and specific conductance .

A

B

C

18 Leaching Tests to Characterize Mine-Waste Material from Historical Mines, Montezuma Mining District, Colo.
0

20

40

60

80

100

120

140

Ca Mg Na Si

Major Elements (mg/L)

Waldorf (5 min) Waldorf (18 hr)

1

10

100

1000

10000

100000

Al Ba Cd Co Cr Cu Fe Mn Ni Pb Zn

log of Trace Metal 

Concentration (ug/L )

Waldorf Mine (5 min) Waldorf Mine (18 Hr)

3.0

3.1

3.1

3.2

3.2

3.3

3.3

3.4

5 minutes 18 hours

pH (Standard Units)

1000

1020

1040

1060

1080

1100

Specific Conductance

(μS/cm)

pH Conductivity

Figure 15. Waldorf mine-waste leachate geochemistry trends (5 minutes vs. 18 hours) for A. selected 

major elements (ICP-AES); B, selected trace metals (ICP-MS); and C, pH and specific conductance .

A

B

C

Results and Discussion 19
0

50

100

150

200

250

300

350

400

Ca Mg Na Si

Major Elements (mg/L)

Santiago (5 min) Santiago (18 hr)

1

10

100

1000

10000

100000

Al Ba Cd Co Cr Cu Fe Mn Ni Pb Zn log of Trace Metal Concentration (μg/L)

Santiago Mine (5 min) Santiago Mine (!8 Hr)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

5 minutes 18 hours

pH (Standard Units)

0

500

1000

1500

2000

Specific Conductance

(μS/cm)

pH Conductivity

Figure 16. Santiago mine-waste leachate geochemistry trends (5 minutes vs. 18 hours) for A. 

selected major elements (ICP-AES); B, selected trace metals (ICP-MS); and C, pH and specific conductance .

A

B

C

20 Leaching Tests to Characterize Mine-Waste Material from Historical Mines, Montezuma Mining District, Colo.
Using the ranking scheme in this way allows the investigator to see which mine-waste piles are potentially the worst 

point-source contributors and which basins have problem sites. 

It should be noted that this ranking scheme only relates 

and pertains to the mine-waste runoff geochemistry because, 

once effluent from any of these sites enters a drainage system 

and is mixed with other waters, a multitude of changes both 

positive and (or) negative may occur in the water body. 

Table 2 shows mine-waste rankings using short-term 

leaching characteristics (5-minute test). This ranking indicates 

which sites produce the most toxic leachate if the piles were 

subject to a meteorological event that produces runoff. The 

Santiago mine-waste is ranked first, followed by the Waldorf 

mine-waste. These two sites are located in the Leavenworth 

Creek drainage. The Togo mine-waste, located in the upper 

Snake River, was ranked third. It is important to note that the 

Santiago mine-waste also produced leachate with detectable 

mercury, the only site in this study to do so.

Table 3 shows mine-waste rankings using longer term 

leaching characteristics (18-hour test). This ranking indicates which sites produce the most toxic leachate after being 

agitated and leached for an extended period of time. These 

rankings are generally the same as those for the 5-minute 

leach test. Leachate from the Waldorf mine-waste was shown 

to have the most toxic geochemical profile according to 

the parameters explained above. The Togo mine-waste was 

second, followed by the Santiago.

Table 4 shows a ranking of the mine-wastes according to NAP results for all the mine-wastes included in this 

study. This ranking of results according to NAP is somewhat 

different than the rankings produced using leachate results. 

However, there also are some similarities. Four of the top five 

ranked using NAP are the same as for the 5-minute and 18-

hour leaching tests, albeit in slightly different order. The Togo 

mine-waste ranked first, meaning it required the most CaCO3

in order to neutralize the waste. The Santiago mine-waste 

was second, followed by the Lower Radical mine-waste. NAP 

Results for all the sites are given in the summaries for individual mine-waste sites and in Appendix 1.

Conclusions

The use of leaching tests like the 5-minute USGS field 

leach test are very effective in providing geochemical data to 

investigators. Data produced from these tests aid in predicting 

the geochemical characteristics of runoff from historical minewaste piles. Leachate geochemical data can be used to fingerprint individual historical mine-wastes, that is, to establish the 

unique leachate geochemical signature for a mine-waste pile. 

When used as an assessment tool on a number of mine-waste 

piles, geochemical fingerprints from individual mine-waste 

can be compared to the geochemical signature of other piles. 

These comparisons allow an investigator to identify the worst 

point-source contributors to stream-water-quality degradation. 

Comparison of the leachate geochemical fingerprints from the 

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Conclusions 21
13 mine-wastes included in this study revealed significant differences in the geochemical characteristics from mine-wastes 

located in adjacent basins.

I found that it is also effective to look at changes in leachate geochemistry over time. Comparison of changes in leachate 

geochemistry after the 5-minute leach test (simulated cloudburst) to those produced from the longer term 18-hour leach 

test showed that not all leachates behave in a similar manner, 

even though they were derived from mine-waste piles located 

relatively close together. Whereas comparative time trends for 

all 13 sites for pH, specific conductance, and sulfate correlated 

well, major- and trace-element concentration changed, sometimes dramatically, as the leachate pH went up or down over 

time. Leachate time trends showed that some wastes are net 

acid producing, while others are net acid consuming over time. 

It was interesting to note that, even though pH went up over 

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22 Leaching Tests to Characterize Mine-Waste Material from Historical Mines, Montezuma Mining District, Colo.
time in leachates from the Santiago and Waldorf mine-wastes, 

these two wastes produced some of the most potentially toxic 

leachate geochemical profiles of all the sites studied. 

Finally, the use of leaching tests in conjunction with 

ranking protocols like those presented here is a very useful 

tool in showing which mine-wastes have the most potential to 

produce toxic runoff. Use of a consistent ranking criteria for 

basin-to-basin comparison can reveal which drainage basins 

contain mine-waste piles having the most impact on tributary 

river systems, as well as which individual mine-waste piles 

may be the greatest contributors as point-source inputs for 

water-quality problems. Examples of the use of relative ranking schemes given in this paper show that, according to the 

leachate geochemical data from the mine-wastes included in 

this study and the criteria used for this investigation, the minewaste piles with the most toxic geochemical profiles were produced from mines in the Leavenworth drainage basin (Waldorf 

and Santiago mines); whereas mine-waste piles located in the 

Deer Creek drainage basin generally had less potential for producing highly toxic leachates.

References

du Bray, Edward A., 1995, Preliminary compilation of descriptive 

geoenvironmental mineral deposit models: U.S. Geological Survey 

Open-File Report 95-0831, 272 p.

Fey, D.L., Church, S.E., Unruh, D.M., and Bove, D.J., 2002, Water 

and sediment study of the Snake River watershed, Colorado: U.S. 

Geological Survey Open-File Report 02-0330, 41 p.

Hageman, Philip L., 2002, Mercury in water by flow injection–cold 

vapor–atomic fluorescence spectrometry, chap. N of Taggart, J.E., 

ed., Analytical methods for chemical analysis of geologic and 

other materials: U.S. Geological Survey Open-File Report 02-

0223.

Hageman, Philip L., and Briggs, Paul H., 2000, A simple field leach 

for rapid screening and qualitative characterization of mine-waste 

material on abandoned mine lands, in ICARD 2000: Proceedings 

from the Fifth International Conference on Acid Rock Drainage, 

Denver, Colorado, May 21–24, 2000: Society for Mining, 

Metallurgy, and Exploration, Inc., p. 1463–1475.

Lapakko, K.A., and Lawrence, R.W., 1993, Modification of the netacid production (NAP) test, in Proceedings, British Columbia 

Mine Reclamation Symposium, Port Hardy, B.C., May 4–7, 1993, 

p. 145–159.

Lovering, T.S., 1935, Geology and ore deposits of the Montezuma 

quadrangle, Colorado: U.S. Geological Survey Professional Paper 

178, 119 p.

Lamothe, P.J., Meier, A.L., and Wilson, Stephen, 1999, The 

determination of forty-four elements in aqueous samples by 

inductively coupled plasma–mass spectrometry: U.S. Geological 

Survey Open-File Report 99-151, 14 p.

Meier, A.L., Grimes, D.J., and Ficklin, W.H., 1994, Inductively 

coupled plasma–mass spectrometry: A powerful tool for mineral 

resource and environmental studies: U.S. Geological Survey 

Circular 1103-A, p. 67–68.

Munroe, E.A., 2000, Abandoned mine lands in Peru Creek, Deer 

Creek, upper Snake River, and Swan River watersheds: Sources 

of metal contamination to the environment and their amelioration 

through passive treatment options: [Report prepared for White 

River National Forest, Dillon Ranger District, Colorado].

Neuerberg, G.J., 1971, Maps showing distribution of selected 

accessory minerals in the Montezuma stock, Summit County, 

Colorado: U.S. Geological Survey Miscellaneous Geologic 

Investigations Map I-608, scale 1:48,000.

Neubert, J.T., Kurtz, J.P., Bove, D.J., Bird, D.A., and Sares, M.A., 

2004, Natural acid rock drainage associated with hydrothermally 

altered terrane in Colorado: Colorado Geological Survey Bulletin 

54, 182 p.

Plumlee, Geoff, and Nash, J.T., 1995, Polymetallic vein and 

replacement deposits, in du Bray, Edward, ed., Preliminary 

compilation of descriptive geoenvironmental mineral deposit 

models: U.S. Geological Survey Open-File Report 95-0831, p. 

121–129.

Smith, K.S., Ramsey, C.A., and Hageman, P.L., 2000, Sampling 

strategy for the rapid screening of mine-waste dumps on 

abandoned mine lands, in ICARD 2000: Proceedings from the 

Fifth International Conference on Acid Rock Drainage, Denver, 

Colorado, May 21–24, 2000: Society for Mining, Metallurgy, and 

Exploration, Inc., p. 1453–1461.

Wilson, A.B., and LaRock, E.J., 1992, Map showing mineralized 

areas and principal lodemines in southern Summit County, 

Colorado: U.S. Geological Survey Miscellaneous Field Studies 

Map MF-2163, scale 1:50,000.

Manuscript approvd for publication June 17, 2004

Published in the Central Region, Denver, Colorado

Editing, layout, photocomposition—Richard W. Scott, Jr.

Section 508 compliance—David G. Walters

Webmaster—Tracy A. Pinto

Graphics by the author

References 23
Appendix 1—Leachate Geochemical Data from 5-Minute and 18-Hour Leaches of 13 

Mine-Waste Composite Samples Included in this Study

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24 Leaching Tests to Characterize Mine-Waste Material from Historical Mines, Montezuma Mining District, Colo.
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Appendix 1 25
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26 Leaching Tests to Characterize Mine-Waste Material from Historical Mines, Montezuma Mining District, Colo.
Appendix 2—Net-Acid Production for 13 Mine-Waste Composite Samples 

Included in this Study

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Appendix 2 27
Arabella Mine

The Arabella mine is located in the Deer Creek drainage 

in the Snake River watershed. The mine is hosted in the Swandyke hornblende gneiss. 

Net-Acidity

4.0 kg CaCO3/ton. 

pH Trend

There was a slight decrease in pH over time in the 

Arabella mine-waste leachate. pH dropped from 4.5 after 5 

minutes to 4.4 after 18 hours. (–0.1 pH units). This indicates 

minor net-acid production in the leachate over time.

Specific Conductance Trend 

Leachate from the Arabella mine-waste had low specific 

conductance with measurements of 30 μS/cm after 5 minutes 

rising to 52 μS/cm after 18 hours.

Sulfate

Arabella leachate sulfate concentration was low and rose 

over time from 0.08 mg/L after 5 minutes to 12 mg/L after 18 

hours. 

Selected Major-Element Trends

The concentration of calcium in the Arabella leachate 

ranged from 0.9 mg/L in the 5-minute leach to 2.1 mg/L after 

18 hours. 

Selected Trace-Metal Trends

Following are summaries of selected trace-element trends 

portrayed in the time study (5-minute vs. 18-hour) of the Arabella mine-waste leachate. 

 Aluminum (Al).—Arabella leachate aluminum 

concentration decreased slightly over time. The 

concentration ranged from 35 μg/L in the 5-minute 

leachate and dropped to 22 μg/L after 18 hours. 

 Cadmium (Cd).—Slightly elevated concentrations 

of cadmium were found with concentrations of 

0.96 μg/L after 5 minutes, rising to 2.3 μg/L after 

18 hours.

 Copper (Cu).—Arabella leachate copper concentrations increased from 57 μg/L in the 5-minute 

leachate to 120 μg/L after 18 hours.

 Iron (Fe).—The Arabella leachate iron concentration was low and a drop in iron concentration was 

observed over time. Iron concentration dropped 

from 38 μg/L in the 5-minute leachate to <1 μg/L 

after 18 hours.

 Mercury (Hg).—Mercury was not detected in the 

Arabella leachate. 

 Manganese (Mn).—Manganese was found in 

the leachate from the Arabella mine-waste. The 

5-minute concentration was 200 μg/L and rose to 

470 μg/L after 18 hours. 

 Nickel (Ni).—Minor concentrations of nickel were 

found in the leachate with slight increase in leachate concentration over time. 5-minute concentration 

was 0.6 μg/L; this value rose to 1.1 μg/L after 18 

hours.

 Lead (Pb).—There were elevated lead concentrations in the Arabella leachate. Also, leachate lead 

concentration rose over time from 270 μg/L after 5 

minutes to 870 μg/L after 18 hours. 

 Zinc (Zn).—Very high concentrations of zinc were 

found in the Arabella leachate, and zinc concentrations rose over time. The 5-minute concentration 

was 230 μg/L; this value rose to 510 μg/L after 18 

hours.

Lower Radical Mine

The Lower Radical mine is located in the Deer Creek 

drainage in the Snake River watershed. The mine is hosted in 

the Swandyke hornblende gneiss. 

Net-Acidity

32 kg CaCO3/ton.

pH Trend

There was a slight decrease in pH over time in the Lower 

Radical mine-waste leachate. pH dropped from 4.8 after 5 

minutes to 4.6 after 18 hours. (–0.2 pH units). This indicates 

slight net-acid production in the leachate over time.

Appendix 3—Mine-Waste Geochemistry Highlights

28 Leaching Tests to Characterize Mine-Waste Material from Historical Mines, Montezuma Mining District, Colo.
Specific Conductance Trend 

Leachate from the Lower Radical mine-waste had low 

specific conductance with measurements of 18 μS/cm after 5 

minutes, rising to 45 μS/cm after 18 hours.

Sulfate

Lower Radical leachate sulfate concentrations were low 

and rose over time from 2.0 mg/L after 5 minutes to 11 mg/L 

after 18 hours. 

Selected Major-Element Trends

Lower Radical leachate had minor concentration of 

calcium, ranging from 0.4 mg/L in the 5-minute leach to 1.5 

mg/L after 18 hours. 

Selected Trace-Metal Trends

Following are summaries of selected trace-element trends 

portrayed in the time study (5-minute vs. 18-hour) of the 

Lower Radical mine-waste leachate. 

 Aluminum (Al).—Lower Radical leachate had low 

concentrations of aluminum, and the concentration 

remained almost constant over time. Concentration 

ranged from 23 μg/L in the 5-minute leachate to 24 

μg/L after 18 hours. 

 Cadmium (Cd).—Minor concentrations of cadmium were found. Values ranged from 0.58 μg/L 

after 5 minutes, rising to 2.2 μg/L after 18 hours.

 Copper (Cu).—Lower Radical leachate copper 

concentrations were minor. Values were 7 μg/L in 

the 5-minute leachate and 16 μg/L after 18 hours.

 Iron (Fe).—Lower Radical leachate iron concentrations were low and dropped over time from 5.2 

μg/L in the 5-minute leachate <1 μg/L after 18 

hours. 

 Manganese (Mn).—Manganese was found in the 

leachate from the Lower Radical mine-waste. The 

5-minute concentration was 260 μg/L and rose to 

930 after 18 hours. 

 Mercury (Hg).—Mercury was not detected in the 

Lower Radical leachate. 

 Nickel (Ni).—Minor concentrations of nickel 

were found in the leachate with a slight increase 

in leachate concentration over time. The 5-minute 

concentration was 1.1 μg/L; this value rose to 2.6 

μg/L after 18 hours.

 Lead (Pb).—There was elevated lead in the leachate and concentration increased over time from 390 

μg/L after 5 minutes to 2,600 μg/L after 18 hours. 

 Zinc (Zn).—Zinc was found in the Lower Radical 

leachate, and zinc concentrations rose over time. 

5-minute concentration was 93 μg/L; this value 

rose to 310 after 18 hours.

Lower Chatauqua Mine

The Lower Chatauqua mine is located in the Deer Creek 

drainage in the Snake River watershed. The mine is hosted 

in the Swandyke hornblende gneiss and schist with galena 

in branching veins or breccias cemented by Manganese-rich 

ankerite and quartz. 

Net-Acidity

3.0 kg CaCO3/ton.

pH Trend

There was an increase in pH over time in the Lower 

Chatauqua mine-waste leachate. pH rose from 5.0 after 5 minutes to 5.4 after 18 hours. (+0.4 pH units). This indicates netacid neutralization of the leachate over time.

Specific Conductance Trend 

Leachate from the Lower Chatauqua mine-waste had low 

specific conductance with measurements of 65 μS/cm after 5 

minutes, rising to 147 μS/cm after 18 hours.

Sulfate

Sulfate concentrations were low and rose over time from 

23 mg/L after 5 minutes to 57 mg/L after 18 hours. 

Selected Major-Element Trends

Lower Chatauqua leachate had calcium that ranged from 

5.3 mg/L in the 5-minute leach to 15 mg/L after 18 hours. 

Selected Trace-Metal Trends

Following are summaries of selected trace-element trends 

portrayed in the time study (5-minute vs. 18-hour) of the 

Lower Chatauqua mine-waste leachates. 

 Aluminum (Al).—Lower Chatauqua leachate had 

minor aluminum concentration. The aluminum 

concentration went down over time. Concentration 

ranged from 17 μg/L in the 5-minute leachate and 

decreased to 7.3 μg/L after 18 hours. 

Appendix 3 29
 Cadmium (Cd).—Minor concentration of cadmium 

was found with concentrations of 2.9 μg/L after 5 

minutes, rising to 8.3 μg/L after 18 hours.

 Copper (Cu).—Minor leachate copper concentration was found, and concentration went down over 

time. Values ranged from 12 μg/L in the 5-minute 

leachate to 5 μg/L after 18 hours.

 Iron (Fe).—Iron was not detected at instrument 

detection limits. Both 5-minute and 18-hour leachates had iron concentrations of <1 μg/L. 

 Manganese (Mn).—Moderately high concentration of manganese was found in the leachate. 

The 5-minute concentration was 1,700 μg/L and 

increased to 4,500 μg/L after 18 hours. 

 Mercury (Hg).—Mercury was not detected in the 

Lower Chatauqua mine-waste leachate.

 Nickel (Ni).—Minor concentration of nickel was 

found with an increase in leachate concentration 

over time. The 5-minute concentration was 5 μg/L 

and rose to 9.6 μg/L after 18 hours.

 Lead (Pb).—High leachate lead concentration was 

found and lead concentration rose over time from 

2,600 μg/L after 5 minutes to 5,800 μg/L after 18 

hours. 

 Zinc (Zn).—Moderately elevated concentrations 

of zinc were found in the Lower Chatauqua leachate, and zinc concentrations rose over time. The 

5-minute concentration was 460 μg/L; this value 

dropped to 1,200 μg/L after 18 hours

General Teller Mine

The General Teller mine is located in the Deer Creek 

drainage in the Snake River watershed. The mine is hosted in 

Swandyke hornblende gneiss with pegmatite intrusions.

Net-Acidity

0.5 kg CaCO3/ton.

pH Trend

There was a slight increase in pH over time in the General Teller mine-waste leachate. pH rose from 5.5 after 5 

minutes to 5.6 after 18 hours. (+0.1 pH units). This indicates 

net-acid neutralization of the leachate over time.

Specific Conductance Trend 

Leachate from the General Teller mine-waste had low 

specific conductance with measurements of 3.7 μS/cm after 5 

minutes, rising to 8.8 μS/cm after 18 hours.

Sulfate

General Teller leachate sulfate concentration was low and 

decreased over time from 5 mg/L after 5 minutes to 3 mg/L 

after 18 hours. 

Selected Major-Element Trends

General Teller leachate had very minor concentration of 

calcium that ranged from 0.15 mg/L in the 5-minute leach to 

0.28 mg/L after 18 hours. Interestingly, sodium concentration 

dropped over time from 1.2 mg/L after 5 minutes to <0.1 mg/L 

after 18 hours.

Selected Trace-Metal Trends

Following are summaries of selected trace-element trends 

portrayed in the time study (5-minute vs. 18-hour) of the General Teller mine-waste leachate. 

 Aluminum (Al).—General Teller leachate had 

low concentrations of aluminum. Concentrations 

ranged from 146 μg/L in the 5-minute leachate and 

rose to 195 μg/L after 18 hours. 

 Cadmium (Cd).—Low concentrations of cadmium 

were found with concentrations of <0.02 μg/L after 

5 minutes, rising to 0.91μg/L after 18 hours.

 Copper (Cu).—General Teller leachate had low 

copper concentrations and ranged from 1.0 μg/L in 

the 5-minute leachate to 1.3 μg/L after 18 hours.

 Iron (Fe).—General Teller leachate iron concentrations were low. Iron concentrations ranged from 67 

μg/L in the 5-minute leachate and rose to 135 μg/L 

after 18 hours. 

 Manganese (Mn).—Low concentrations of manganese were found in leachate from the General 

Teller mine-waste. Manganese values ranged from 

4.8 μg/L to 22.8 after 18 hours. 

 Mercury (Hg).—Mercury was not detected in the 

General Teller leachate. 

 Nickel (Ni).—Minor concentrations of nickel were 

found in the leachate with a very slight increase 

in leachate concentration over time. The 5-minute 

concentration was <0.4 μg/L, rising to 0.5 μg/L 

after 18 hours.

 Lead (Pb).—Leachate lead concentration was 

minor and rose over time from 3 μg/L after 5 minutes to 12.6 μg/L after 18 hours. 

 Zinc (Zn).—Minor concentrations of zinc were 

found in the General Teller leachate and the concentration rose over time. The 5-minute zinc concentration was 5.4 μg/L; this value rose to 29.8 

μg/L after 18 hours.

30 Leaching Tests to Characterize Mine-Waste Material from Historical Mines, Montezuma Mining District, Colo.
Cashier Mine

The Cashier mine is located in the very upper reach of 

the Snake River. The mine is hosted in Swandyke hornblende 

gneiss, with barite gangue, and no ankerite. 

Net-Acidity

10.5 kg CaCO3/ton.

pH Trend

There was an increase in pH over time in the Cashier 

mine-waste leachate. pH rose from 4.7 after 5 minutes to 5.0 

after 18 hours. (+0.3 pH units). This indicates net-acid neutralization in the leachate over time.

Specific Conductance Trend 

Leachate from the Cashier mine-waste had low specific 

conductance with measurements of 155 μS/cm after 5 minutes, 

rising to 212 μS/cm after 18 hours.

Sulfate

Cashier leachate sulfate concentration was low and went 

up over time from 60 mg/L after 5 minutes to 91 mg/L after 18 

hours. 

Selected Major-Element Trends

The leachate had minor concentration of calcium that 

ranged from 8.5 mg/L in the 5-minute leach to 14 mg/L after 

18 hours.

Selected Trace-Metal Trends

Following are summaries of selected trace-element trends 

portrayed in the time study (5-minute vs. 18-hour) of the 

Cashier mine-waste leachate. 

 Aluminum (Al).—Cashier leachate had low concentrations of aluminum. Concentration ranged from 

54 μg/L in the 5-minute leachate and decreased to 

28 μg/L after 18 hours. 

 Cadmium (Cd).—Low concentrations of cadmium 

were found, with concentrations of 6.5 μg/L after 5 

minutes, rising to 14 μg/L after 18 hours.

 Copper (Cu).—Copper concentration was moderately high and decreased over time from 740 μg/L 

in the 5-minute leachate to 640 μg/L after 18 hours.

 Iron (Fe).—No iron was found at instrument detection limits in the leachate from the Cashier minewaste. Both the 5-minute and 18-hour leachate 

concentration were <1 μg/L. 

 Manganese (Mn).—Very high concentration of 

manganese was found. Manganese values ranged 

from 12,000 μg/L in the 5-minute leachate to 

19,000 after 18 hours.

 Mercury (Hg).—Mercury was not detected in the 

Cashier leachate. 

 Nickel (Ni).—Minor concentrations of nickel were 

found in the leachate with an increase in leachate 

concentration over time. The 5-minute concentration was 11 μg/L, rising to 18 μg/L after 18 hours.

 Lead (Pb).—Leachate lead concentration was elevated and did not change over time staying at 1,200 

μg/L in both the 5-minute and 18-hour tests. 

 Zinc (Zn).—High concentrations of zinc were 

found in the Cashier leachate and the concentration 

rose over time. The 5-minute zinc concentration 

was 1,100 μg/L; this value rose to 2,200 μg/L after 

18 hours.

Togo Mine

The Togo mine is located in the upper reach of the Snake 

River prior to confluence with Deer Creek. The mine is hosted 

in the Idaho Springs formation.

Net-Acidity

83 kg CaCO3/ton.

pH Trend

There was a slight decrease in pH over time in the Togo 

mine-waste leachate. pH went down from 3.0 after 5 minutes 

to 2.9 after 18 hours. (–0.1 pH units). This indicates net-acid 

production the leachate over time.

Specific Conductance Trend 

Leachate from the Togo mine-waste had moderate conductance with measurements of 556 μS/cm after 5 minutes, 

rising to 718 μS/cm after 18 hours.

Sulfate

Togo leachate sulfate concentration went up over time 

from 124 mg/L after 5 minutes to 139 mg/L after 18 hours. 

Appendix 3 31
Selected Major-Element Trends

Togo leachate had minor concentration of calcium that 

ranged from 0.9 mg/L in the 5-minute leach to 1.1 mg/L after 

18 hours.

Selected Trace-Metal Trends

Following are summaries of selected trace-element trends 

portrayed in the time study (5-minute vs. 18-hour) of the Togo 

mine-waste leachate. 

 Aluminum (Al).—Togo leachate had high concentrations of aluminum. Concentration ranged from 

5,890 μg/L in the 5-minute leachate and rose to 

5,940 μg/L after 18 hours. 

 Cadmium (Cd).—Low concentrations of cadmium 

were found with concentrations of 0.21 μg/L after 5 

minutes, rising to 0.26μg/L after 18 hours.

 Copper (Cu).—Togo leachate copper concentrations ranged from 83.8 μg/L in the 5-minute leachate to 114 μg/L after 18 hours.

 Iron (Fe).—Togo leachate iron concentrations were 

the highest of all 13 sites studied. Iron concentration ranged from 22,100 μg/L in the 5-minute 

leachate and rose to 22,600 μg/L after 18 hours. 

 Manganese (Mn).—Somewhat high concentrations 

of manganese were found in leachate from the 

Togo mine-waste. Manganese values ranged from 

238 μg/L in the 5-minute leachate to 284 after 18 

hours. 

 Mercury (Hg).—Mercury was not detected in the 

Togo leachate.

 Nickel (Ni).—Minor concentrations of nickel were 

found in the leachate with a minor increase in 

leachate concentration over time. The 5-minute 

concentration was 11.7 μg/L, rising to 15.6 μg/L 

after 18 hours.

 Lead (Pb).—Leachate lead concentration was 

minor and decreased over time from 3 μg/L after 5 

minutes to 1.2 μg/L after 18 hours. 

 Zinc (Zn).—Moderate concentrations of zinc were 

found in the Togo leachate and the concentration 

rose over time. The 5-minute zinc concentration 

was 99.7 μg/L; this value rose to 112 μg/L after 18 

hours.

Burke Mine

The Burke mine is located in the Snake River watershed 

below the confluence with Deer Creek. The mine is hosted in 

the Swandyke hornblende gneiss. 

Net-Acidity

5.0 kg CaCO3/ton.

pH Trend

There was a slight increase in pH over time in the Burke 

mine-waste leachate. pH rose from 5.0 after 5 minutes to 5.1 

after 18 hours. (+0.1 pH units). This indicates net-acid production in the leachate over time.

Specific Conductance Trend 

The Burke leachate had the second lowest conductance of 

the 13 sites studied, with measurements of 9.38 μS/cm after 5 

minutes, rising to 13.3 μS/cm after 18 hours.

Sulfate

The sulfate concentration was very low with concentrations of 4 mg/L after 5 minutes and 5 mg/L after 18 hours. 

Selected Major-Element Trends

Burke leachate had very low calcium concentration that 

ranged from <0.2 mg/L in the 5-minute leach to 0.4 mg/L after 

18 hours. 

Selected Trace-Metal Trends

Following are summaries of selected trace-element trends 

portrayed in the time study (5-minute vs. 18-hour) of the 

Burke mine-waste leachate. 

 Aluminum (Al).—This leachate had aluminum 

concentration that ranged from 19.5 μg/L in the 5-

minute leachate and increased to 182 μg/L after 18 

hours. 

 Cadmium (Cd).—Minor concentration of cadmium 

was found in the Burke mine-waste leachate with 

values of <0.02 μg/L after 5 minutes, rising to 0.38 

μg/L after 18 hours.

 Copper (Cu).—Minor leachate copper concentration was found and the concentration rose over 

time. Values ranged from 0.97 μg/L in the 5-minute 

leachate to 1.6 μg/L after 18 hours.

 Iron (Fe).—Iron was found in moderate concentration in leachate from the Burke mine-waste. Leachate concentration increased over time from 96 μg/L 

in the 5-minute leachate to 563μg/L after 18 hours. 

 Manganese (Mn).—Low concentration of manganese was found in the leachate. 5-minute leachate 

concentration was 1.5 μg/L and increased to 6.3 

μg/L after 18 hours. 

 Mercury (Hg).—Mercury was not detected in the 

Burke leachate.

 Nickel (Ni).—Very minor concentration of nickel 

32 Leaching Tests to Characterize Mine-Waste Material from Historical Mines, Montezuma Mining District, Colo.
was found. The 5-minute leachate concentration 

was <0.4 μg/L, increasing to 0.5 μg/L after 18 

hours.

 Lead (Pb).—Low leachate lead concentration was 

found and concentration increased over time from 

1.5 μg/L after 5 minutes to 15.4 μg/L after 18 

hours. 

 Zinc (Zn).—Minor concentration of zinc was found 

in the Burke leachate, and zinc concentration 

increased over time. The 5-minute leachate concentration was 11.3 μg/L; this value rose slightly to 

12.6 μg/L after 18 hours.

Jack Pine Mine

The Jack Pine mine is located in Stevens Gulch in the 

Clear Creek watershed. The mine is hosted in the Idaho 

Springs Formation. 

Net-Acidity

17.5 kg CaCO3/ton.

pH Trend

There was a slight decrease in pH over time in the Jack 

Pine mine-waste leachate. pH dropped from 5.1 after 5 minutes to 5.0 after 18 hours. (–0.1 pH units). This indicates netacid production in the leachate over time.

Specific Conductance Trend 

Jack Pine leachate had low specific conductance with 

measurements of 163 μS/cm after 5 minutes, rising to 261 

μS/cm after 18 hours.

Sulfate

Sulfate concentration was low with concentrations of 68 

mg/L after 5 minutes and 106 mg/L after 18 hours. 

Selected Major-Element Trends

Jack Pine leachate had moderately low calcium concentration that ranged from 10.4 mg/L in the 5-minute leach to 

14.6. mg/L after 18 hours. 

Selected Trace-Metal Trends

Following are summaries of selected trace-element trends 

portrayed in the time study (5-minute vs. 18-hour) of the Jack 

Pine mine-waste leachate. 

 Aluminum (Al).—No aluminum was found in the 

leachate. Both the 5-minute and 18-hour values 

were <2 μg/L.

 Cadmium (Cd).—Elevated concentration of cadmium was found in the leachate with values of 160 

μg/L after 5 minutes, increasing to 313 μg/L after 

18 hours.

 Copper (Cu).—Moderate leachate copper concentration was found and the concentration decreased 

slightly over time. Values ranged from 20.6 μg/L in 

the 5-minute leachate to 15.2 μg/L after 18 hours.

 Iron (Fe).—No iron was found in the Jack Pine 

leachate at the ICP-MS detection limit. Both the 5-

minute and 18-hour leachates were <50 μg/L. 

 Manganese (Mn).—Elevated manganese was found 

in the Jack Pine leachate. The 5-minute concentration was 2,280 μg/L, increasing to 3,560 μg/L after 

18 hours. 

 Mercury (Hg).—Mercury was not detected in the 

Jack Pine leachate.

 Nickel (Ni).—Nickel was found in the leachate 

with a 5-minute concentration of 2.4 μg/L, increasing to 4.7 μg/L after 18 hours.

 Lead (Pb).—High leachate concentration of 

leachate lead was found, and lead concentration 

increased over time from 1,860 μg/L after 5 minutes to 2,000 μg/L after 18 hours. 

 Zinc (Zn).—Very high concentration of zinc was 

found in the Jack Pine leachate, and zinc concentration increased over time. The 5-minute concentration was 19,000 μg/L; this value increased to 

37,700 μg/L after 18 hours. This is one of the highest concentrations of zinc found in the 13 minewaste sites included in this study. .

Superior Mine

The Superior mine is located in the Snake River drainage 

just below the confluence with Deer Creek. The mine is hosted 

in the Swandyke hornblende gneiss. 

Net-Acidity

5.0 kg CaCO3/ton.

pH Trend

There was an increase in pH over time in the Superior 

mine-waste leachate. pH rose from 5.0 after 5 minutes to 5.4 

after 18 hours. (+0.4 pH units). This indicates net-acid neutralization of the leachate over time.

Appendix 3 33
Specific Conductance Trend 

Superior leachate had low specific conductance with 

measurements of 33.9 μS/cm after 5 minutes, rising to 61.8 

μS/cm after 18 hours.

Sulfate

Sulfate concentration was low in the leachate with concentrations of 13 mg/L after 5 minutes and 21 mg/L after 18 

hours. 

Selected Major-Element Trends

Superior leachate had low calcium concentration that 

ranged from 2.02 mg/L in the 5-minute leach to 4.31 mg/L 

after 18 hours. 

Selected Trace-Metal Trends

Following are summaries of selected trace-element trends 

portrayed in the time study (5-minute vs. 18-hour) of the 

Superior mine-waste leachate. 

 Aluminum (Al).—This leachate had aluminum concentration that ranged from 18 μg/L in the 5-minute 

leachate and decreased to 8.4 μg/L after 18 hours.

 Cadmium (Cd).—Minor concentration of cadmium 

was found in the Superior mine-waste leachate 

with values of 0.7 μg/L after 5 minutes, rising to 

1.69 μg/L after 18 hours.

 Copper (Cu).—Minor leachate copper concentration was found and the concentration decreased 

slightly over time. Values ranged from 0.24 μg/L in 

the 5-minute leachate to 0.22 μg/L after 18 hours.

 Iron (Fe).—Iron was found in low concentration in 

the leachate, and concentration decreased over time 

from 3.3 μg/L in the 5-minute to 1.7 μg/L after 18 

hours. 

 Manganese (Mn).—Moderate concentration of 

manganese was found in the Superior leachate. The 

5-minute concentration was 520 μg/L and increased 

to 1,380 μg/L after 18 hours. 

 Mercury (Hg).—Mercury was not detected in the 

Superior leachate.

 Nickel (Ni).—Nickel was found in the leachate, 

with a 5-minute concentration of 1.8 μg/L, increasing to 4.2 μg/L after 18 hours.

 Lead (Pb).—Low leachate lead concentration was 

found and concentration decreased over time from 

1.6 μg/L after 5 minutes to 1.0 μg/L after 18 hours. 

 Zinc (Zn).—Moderate concentration of zinc was 

found in the Superior leachate, and zinc concentration increased over time. The 5-minute concentration was 180 μg/L, increasing to 387 μg/L after 18 

hours.

Wild Irishman Mine

The Wild Irishman mine is located in the Upper Saints 

John Creek drainage basin. Saints John Creek flows into the 

Snake River below the confluence of Deer Creek and the 

Snake River. Host rock for this mine is Swandyke hornblende 

gneiss and ore on dump from lower adit indicates veins consisted largely of “manganosiderite” with moderate amounts 

of galena. On dump above lower adit, manganosiderite is rare 

and quartz is the dominant gangue mineral. The mine is hosted 

in the Swandyke hornblende gneiss. 

Net-Acidity

6.5 kg CaCO3/ton.

pH Trend

There was a significant increase in pH over time in the 

Wild Irishman mine-waste leachate. pH rose from pH 5.5 after 

5 minutes to pH 6.6 after 18 hours. (+1.1 pH units). This indicates net-acid neutralization in the leachate over time.

Specific Conductance Trend 

The leachate had low specific conductance with measurements of 33.5 μS/cm after 5 minutes, rising to 113 μS/cm after 

18 hours.

Sulfate

The sulfate concentration was low with concentrations of 

13 mg/L after 5 minutes and 30 mg/L after 18 hours. 

Selected Major-Element Trends

Wild Irishman leachate had low calcium concentration 

that ranged from 2.8 mg/L in the 5-minute leach to 12.4 mg/L 

after 18 hours. 

Selected Trace-Metal Trends

Following are summaries of selected trace-element trends 

portrayed in the time study (5-minute vs. 18-hour) of the Wild 

Irishman mine-waste leachate. 

 Aluminum (Al).—This leachate had aluminum 

34 Leaching Tests to Characterize Mine-Waste Material from Historical Mines, Montezuma Mining District, Colo.
concentration that ranged from 20.1 μg/L in the 5-

minute leachate and decreased to 2.6 μg/L after 18 

hours. There was a net aluminum loss in the leachate over time.

 Cadmium (Cd).—Minor concentration of cadmium 

was found in the leachate with values of 0.16 μg/L 

after 5 minutes, increasing to 0.43 μg/L after 18 

hours.

 Copper (Cu).—Minor leachate copper concentration was found and the concentration increased 

slightly over time. Values ranged from 0.50 μg/L in 

the 5-minute leachate to 0.55 μg/L after 18 hours.

 Iron (Fe).—No iron was found in the Wild Irishman leachate at the ICP-MS detection limit. Both 

the 5-minute and 18-hour leachates were <50 μg/L. 

 Manganese (Mn).—Moderate concentration of 

manganese was found in the leachate. The 5-

minute concentration was 281 μg/L and increased 

to 661 μg/L after 18 hours. 

 Mercury (Hg).—Mercury was not detected in the 

Wild Irishman leachate.

 Nickel (Ni).—Nickel was found in the leachate with 

a 5-minute concentration of 0.60 μg/L, increasing 

to 1.0 μg/L after 18 hours.

 Lead (Pb).—Low concentration of lead was found 

and lead concentration decreased over time from 

2.6 μg/L after 5 minutes to 1.3 μg/L after 18 hours. 

 Zinc (Zn).—Moderate concentration of zinc was 

found in the Wild Irishman leachate, and the zinc 

concentration increased over time. 5-minute concentration was 6.0 μg/L, increasing to 43.8 μg/L 

after 18 hours.

Grizzly Mine

The Grizzly mine is located in Grizzly Gulch in the Clear 

Creek watershed. The mine is hosted in the Idaho Springs formation. 

Net-Acidity

1.3 kg CaCO3/ton.

pH Trend

There was no change in pH over time in the Grizzly 

mine-waste leachate. pH stayed at 6.9 in both the 5-minute and 

18-hour leachates. The leachate was neither net-acid producing nor net-acid consuming.

Specific Conductance Trend 

Grizzly leachate had low specific conductance with 

measurements of 25 μS/cm after 5 minutes, increasing to 

70 μS/cm after 18 hours.

Sulfate

Sulfate concentration was very low with concentrations 

of 5 mg/L after 5 minutes and 8 mg/L after 18 hours. 

Selected Major-Element Trends

This leachate had low calcium concentration that ranged 

from 1.8 mg/L in the 5-minute leach to 6.9 mg/L after 18 

hours. 

Selected Trace-Metal Trends

Following are summaries of selected trace-element trends 

portrayed in the time study (5-minute vs. 18-hour) of the Grizzly mine-waste leachate. 

 Aluminum (Al).—This leachate had moderate aluminum concentration that ranged from 57.1 μg/L 

in the 5-minute leachate and increased to 364 μg/L 

after 18 hours.

 Cadmium (Cd).—Minor concentration of cadmium 

was found in the Grizzly mine-waste leachate with 

values of <0.02 μg/L after 5 minutes, and 0.03 μg/L 

after 18 hours.

 Copper (Cu).—Minor leachate copper concentration was found. Values ranged from 2.0 μg/L in the 

5-minute leachate to 2.2 μg/L after 18 hours.

 Iron (Fe).—Iron was found in low concentration in 

the leachate, and concentration increased over time 

from <50 μg/L in the 5-minute to 129 μg/L after 18 

hours. 

 Manganese (Mn).—Minor concentration of manganese was found in the Grizzly leachate. The 5-

minute concentration was 2.7 μg/L and increased to 

7.4 μg/L after 18 hours. 

 Mercury (Hg).—Mercury was not detected in the 

Grizzly leachate. 

 Nickel (Ni).—Nickel was found in low concentration in the leachate with a 5-minute concentration 

of <0.4 μg/L that increased to 0.8 μg/L after 18 

hours.

 Lead (Pb).—Low concentration of leachate lead 

was found and concentration increased over time 

from 4.8 μg/L after 5 minutes to 11.1 μg/L after 18 

hours. 

 Zinc (Zn).—Minor concentration of zinc was found 

in the Grizzly leachate, and zinc concentrations 

increased slightly over time. The 5-minute concentration was 5.7 μg/L; this value increased to 9.9 

μg/L after 18 hours.

Appendix 3 35
Waldorf Mine

The Waldorf mine is located in the very upper reach of 

Leavenworth Creek in the Clear Creek watershed. The mine 

is hosted in Idaho Springs schist and rhyolitic intrusive rocks, 

although Silver Plume granite is present near the adit and is 

exposed within the tunnel as well. Lovering (1938) reports 

that the walls of the tunnel were coated with a copper “lime” 

during his visit

Net-Acidity

24.0 kg CaCO3/ton.

pH Trend

An increase in pH occurred in leachate from the Waldorf 

mine-waste composite that showed a rise in pH from 3.1 after 

5 minutes to 3.3 after 18 hours. (+0.2 pH units). This indicates 

some neutralization of the leachate over time.

Specific Conductance Trend 

Leachate from the Waldorf mine-waste had high specific 

conductance with measurements of 1,040 μS/cm after 5 minutes, rising to 1,092 μS/cm after 18 hours.

Sulfate

Waldorf leachate sulfate concentration increased over 

time from 443 mg/L after 5 minutes to 504 mg/L after 18 

hours.

Selected Major-Element Trends

Waldorf leachate had the second highest leachate concentration of calcium that ranged from 82 mg/L in the 5-minute 

leachate to 120 mg/L after 18 hours. 

Selected Trace-Metal Trends

Following are summaries of selected trace-element trends 

portrayed in the time study (5-minute vs. 18-hour) of the Waldorf mine-waste leachate. 

 Aluminum (Al).—Waldorf leachate had the highest 

aluminum concentration of the 13 dumps included 

in this study. Aluminum concentration decreased 

slightly over time. Concentration was 8,230 μg/L in 

the 5-minute leachate and decreased to 8,010 μg/L 

after 18 hours. 

 Cadmium (Cd).—Elevated concentrations of cadmium were found with concentrations of 122 μg/L 

after 5 minutes, rising to 140 μg/L after 18 hours.

 Copper (Cu).—Waldorf leachate copper concentration was second highest of all the leachates studied. 

Only leachate from the Santiago mine-waste had 

higher copper concentrations. Waldorf leachate 

copper ranged from 4,400 in the 5-minute leachate 

to 4,410 μg/L after 18 hours.

 Iron (Fe).—Waldorf leachate iron concentration 

was high, especially in the 5-minute leachate. A 

decrease in iron concentration was seen over time 

from 7,910 μg/L in the 5-minute leachate to 744 

μg/L after 18 hours. This is a decrease in iron concentration of more than an order of magnitude. 

 Manganese (Mn).—Very high concentration of 

manganese was found in leachate from the Waldorf 

mine-waste, second only to the Santiago. The 5-

minute concentration was 31,500 μg/L; this value 

increased to 40,900 after 18 hours. 

 Mercury (Hg).—Mercury was not detected in the 

Waldorf leachate.

 Nickel (Ni).—Elevated concentrations of nickel 

were found in the leachate with a slight increase 

in leachate concentration over time. The 5-minute 

concentration was 117 μg/L; this value increased to 

126 μg/L after 18 hours.

 Lead (Pb).—Leachate lead concentration increased 

over time from 190 μg/L after 5 minutes to 1,290 

μg/L after 18 hours. 

 Zinc (Zn).—Very high concentrations of zinc were 

found in the Waldorf leachate and zinc concentrations increased over time. The 5-minute concentration was 23,900 μg/L, increasing to 25,500 after 18 

hours.

Santiago Mine

The Santiago mine is located near the Waldorf mine in 

the Leavenworth Creek/Clear Creek watershed. Host rock is 

Silver Plume granite and biotite-quartz-sillimanite schist. One 

of the largest producers in the area the ore consisted of galena, 

sphalerite, pyrite and some chalcopyrite; quartz and ankerite 

comprise the dominant gangue minerals and ankerite was 

reported to be very abundant in some of the deeper workings. 

Net-Acidity

73.0 kg CaCO3/ton.

pH Trend

An increase in pH occurred in leachate from the Santiago 

mine-waste composite that showed a spike in pH from 3.6 

36 Leaching Tests to Characterize Mine-Waste Material from Historical Mines, Montezuma Mining District, Colo.
after 5 minutes to 5.2 after 18 hours (+1.6 pH units). This indicates neutralization of the leachate over time.

Specific Conductance Trend 

Leachate from the Santiago mine-waste had the highest 

specific conductance of all the 13 dumps studied, with specific 

conductance of 1,730 μS/cm after 18 hours. This followed the 

5-minute reading of 1,396 μS/cm.

Sulfate

Santiago leachate had the highest concentration of sulfate, and the concentration increased over time from 736 mg/L 

after 5 minutes to 1,040 mg/L after 18 hours. 

Selected Major-Element Trends

Santiago leachate had the highest concentration of calcium, ranging from 230 mg/L in the 5-minute leachate to 370 

mg/L after 18 hours. The high calcium concentration is probably responsible for the increase in the leachate pH over time. 

Selected Trace-Metal Trends

Following are summaries of selected trace-element trends 

portrayed in the time study (5-minute vs. 18-hour) of the Santiago mine-waste leachate. 

 Aluminum (Al).—Found to be high in the 5-minute 

leachate at 2,060 μg/L but decreased after 18 hours 

to a concentration of 11.3 μg/L. 

 Cadmium (Cd).—Slightly elevated concentrations 

of cadmium were found with concentrations of 174 

μg/L after 5 minutes, and 180 μg/L after 18 hours.

 Copper (Cu).—Copper concentration was high in 

the 5-minute leachate at 6,590 μg/L but decreased 

to 236 μg/L after 18 hours.

 Iron (Fe).—Leachate iron was elevated in the 5-

minute leachate at 836 μg/L and decreased to <50 

μg/L after 18 hours. 

 Manganese (Mn).—Very high concentration of 

manganese was found in leachate from the Santiago. The 5-minute concentration was 44,200 μg/L 

increasing to 56,100 after 18 hours. 

 Mercury (Hg).—Mercury was detected in the 

leachate from the Santiago mine-waste pile. Mercury concentration was 25 ng/L (ppt) after 5 minutes, rising to 30 ng/L (ppt) after 18 hours. 

 Nickel (Ni).—Slightly elevated in the leachate with 

a slight increase in leachate concentration over 

time. 5-minute concentration was 120 μg/L; this 

value increased to 133 μg/L after 18 hours.

 Lead (Pb).—Leachate lead decreased from 234 μg/

L after 5 minutes to a concentration of 28.1 μg/L 

after 18 hours. 

 Zinc (Zn).—Very high concentration of zinc was 

found in the leachate and zinc concentration 

decreased over time. The 5-minute concentration 

was 26,000 μg/Lthe 18-hour value dropped to 

22,600 μg/L.

Appendix 3 37