EPA-670/2-75-048
June 1975
Environmental Protection Technology Series
WATER QUALITY CONTROL IN MINE SPOILS
UPPER COLORADO RIVER BASIN
National Environmental Research Center
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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EPA-670/2-75-048
June 1975
WATER QUALITY CONTROL IN MINE SPOILS
UPPER COLORADO RIVER BASIN
By
David B. McWhorter
Rodney K. Skogerboe
Gaylord V. Skogerboe
Colorado State University
Fort Collins, Colorado 80523
Grant No. R802621
Program Element No. 1BB040
Project Officer
Elmore C. Grim
Mining Pollution Control Branch (Cincinnati, Ohio)
Industrial Waste Treatment Research Laboratory
Edison, New Jersey 08817
NATIONAL ENVIRONMENTAL RESEARCH CENTER
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI. OHIO 45268
For >a!e by the Superintendent of Document!. U.S. Government
Printing Office, Washington. D.C. 20402
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REVIEW NOTICE
The National Environmental Research Center--Cincinnati has reviewed this
report and approved its publication. Approval does not signify that the
contents necessarily reflect the views and policies of the U.S. Environmental
Protection Agency, nor does mention of trade names or commercial products
constitute endorsement or recommendation for use.
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FOREWORD
Man and his environment must be protected from the adverse effects of
pesticides, radiation, noise and other forms of pollution, and the unwise
management of solid waste. Efforts to protect the environment require a
focus that recognizes the interplay between the components of our physical
environmentair, water, and land. The National Environmental Research
Centers provide this multidisciplinary focus through programs engaged in
studies on the effects of environmental contaminants on man
and the biosphere, and
a search for ways to prevent contamination and to recycle
valuable resources.
To meet the energy demands of this Nation, the coals of the western
United States must be exploited. This study is one of the first to assess
the potential degradation of ground and surface waters by surface mining.
Surface coal mines in Colorado and New Mexico were studied for a year,
and in addition, the potential water quality problems from a copper-zinc-
lead mill were evaluated.
A. W. Breidenbach, Ph.D.
Director
National Environmental
Research Center, Cincinnati
111
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ABSTRACT
Mining is an extractive industry, and the potential for adversely effect-
ing land and water utilization by other industries or municipalities
may be large. The purpose of this study was to identify potential water
quality problems associated with runoff and percolation through mine
spoils at selected sites in the Upper Colorado River Basin, and to pro-
vide a quantitative description of the interactions among geological,
chemical, hydrological, and meteorological variables influencing poten-
tial water quality degradation.
The results of this study show that the production of soluble salts from
mine spoils into receiving waters is probably the most significant water
quality problem that can be expected. No significant release of heavy
metals was observed in the coal mine spoils studied. Some signifcant
heavy metal concentrations were observed in the stream below the tailings
disposal area from a copper-zinc-lead mill, A portion of these are
contributed by the tailings, but a variety of old mines and mine dumps
also make a contribution. The quality of percolate and runoff from
spoils was found to correspond to the constituents of extracts prepared
from saturated pastes of the spoil material. A method of estimating
salt production into receiving waters was derived and found to agree
very well with measured salt pickups at one coal site studied. The
minimum quantities of salts that will eventually be released from the
spoils studied are estimated.
This report was submitted in fulfillment of Grant No. R802621 by Colorado
State University under the sponsorship of the Environmental Protection
Agency. Work was completed as of June 30, 1974.
IV
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CONTENTS
Page
Abstract . , , , ii
List of Figures , , iv
List of Tables v
Acknowledgements vi
Sections
I Conclusions 1
II Recommendations , 5
III Introduction 6
IV Geologic-Hydrologic Perspective 10
V Field and Laboratory Investigations ... 19
VI Water Quality and Relation to Spoil Characteristics .... 31
VII General Chemical and Geological Considerations 52
VIII Projected Water Quality Degradation from Strip Mine Spoils . 60
IX References 68
X Appendices 70
A. Water Quality Data - Edna Mine Site 70
B. Water Quality Data - Idarado Mine Site 77
C. Edna Mine Site - Saturated Soil Paste, and Plant
Nutrient Analysis . 87
D. Navajo Mine Site - Saturated Soil Paste and Plant
Nutrient Analysis 90
E. Idarado Mine Site - Saturated Soil Paste and Plant
Nutrient Analysis 91
F. Column Leaching Data 92
G. Infiltration Data 97
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FIGURES
No. Page
1 Location of the Navajo Mine 11
2 Location of the Edna Mine , 14
3 Location of the Idarado Mine 16
4 Edna Mine Spoils, Trout Creek, and Water Quality Monitoring
Stations 20
5 Idarado Mine, San Miguel River and Tributaries, and Water
Quality Monitoring Stations 22
6 Approximate Spoil Sample Locations at the Navajo Mine .... 27
7 Specific Conductance Profiles on an Eight Kilometer Reach
of Trout Creek 33
8 Specific Conductance on Trout Creek for a Nine Month Period . 35
9 Water Table Map Near Station C8 40
10 Water Table Map at Tailings Pond No. 6 48
11 Correlation of Calcium and Magnesium with Sulfate 54
12 Normalized Leaching Data from Three Samples of Overburden -
Navajo Mine 61
13 Normalized Leaching Data from Six Samples of Spoils and
Overburden - Edna Mine 62
VI
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TABLES
No.
1 April, 1974, Water Quality on Trout Creek 32
2 Discharge and Specific Conductance at Stations C2 and C3 - 36
3 Average Chemical Characteristics of Spoil, Runoff, and
Groundwater , , 38
4 Sediment Concentrations at Stations C2 and C8 . . , 38
5 Discharge of Total Dissolved Solids at Stations C2, C3, and
C8 41
6 April, 1974, Water Quality on the San Miguel River 44
7 Discharge of Water and Dissolved Solids at Stations T4, T5,
and T8 45
8 Average Chemical Characteristics of Water and Tailings Between
Stations T4 and T8 47
9 Average Chemical Characteristics of Water, Spoil, and Over-
burden, Navajo Mine 50
10 Sodium Absorption Ratio and Exchangeable Sodium Percentages
for Navajo Samples 57
VII
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ACKNOWLEDGEMENTS
The outstanding help and cooperation of Pittsburg and Midway Coal Mining
Company, Idarado Mining Company, and Utah International, Inc. are grate-
fully acknowledged. These companies provided maps, data, and background
information that were essential to the completion of the investigation,
as well as access to their properties and assistance in field work.
Mr. J. A. Brookman and Mr. P. Hammer, research technicians, spent many
hours of their own time attending to the details of sample collection,
chemical analysis, and field data collection. The conditions were often
adverse, making it necessary to use snowshoes and skis at temperatures
which fell below -30°F. The efforts of these individuals and those of
Mrs. D. English in doing all the typing for the project are greatly
appreciated.
Finally, the advice of Mr. E. C. Grim, EPA project officer, and Mr. R. D.
Hill, Chief of Mine Drainage Pollution Control Activities, is appreciated.
Their experience with similar investigations at other locations and their
contacts with other investigators were very helpful.
Vlll
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SECTION I
CONCLUSIONS
The most significant water pollution potential of the coal strip mine
spoils investigated results from the soluble salt content of the over-
burden materials. The major constituents in surface and subsurface
runoff from the spoils are sodium, calcium, magnesium, sulfate, and bi-
carbonate. The principal sources of sulfate are probably epsomite and
gypsum. Sodium in the runoff, apparently, results from being flushed
from cation exchange sites on the clay particles in the spoil. These
conclusions are expected to apply, in different degrees, to the majority
of strip mine spoils in the Rocky Mountain and Northern Great Plains
regions. This is *rue because almost all the surface mineable coal
reserves reside in formations of Upper Cretaceous and Early Tertiary age,
formed under generally similar geologic conditions.
The minimum soluble salt contents of the two coal mine spoils studied
are 2.4 and 23 kilograms per cubic meter of spoil. These results do
not include the effects of weathering and microbial activity that will
tend to increase the quantity of salts available for removal by water.
The 2.4 kilograms of soluble salt per cubic meter derived for the Edna
Mine on Trout Creek was determined using 34 samples from 12 locations
covering the entire disturbed area, and is believed to be reasonably
representative of the exposed spoil. The chemical characteristics of
samples of the Edna spoils and overburden exhibited a great deal of
uniformity. The 23 kilograms per cubic meter determined for the Navajo
Mine was derived from 3 samples formed by compositing 11 samples by
depth interval. All of these samples were collected in a relatively
localized area in one pit. Thus, the reported soluble salt content is
not representative of the entire disturbed area at the Navajo Mine.
Utah International personnel report a great deal of variability in
spoil and overburden characteristics.
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A net salt pickup of 6187 metric tons (6700 tons) over a nine month
period was observed between monitoring stations upstream and downstream
of the Edna Mine on Trout Creek. Salt pickup measured on one portion of
the spoil area was found to be 8.42 metric tons per hectare (3.7 tons/acre)
in a surface and subsurface runoff of 40 cm (16 in), The measured
normalized rate of salt pickup is 0.21 metric tons per hectare per centi-
meter of surface and groundwater runoff (0.23 tons/acre/in). Over 80
percent of the total load was contributed during the spring runoff in
April, May and early June. For perspective, the annual salt pickup from
irrigated crop land in Grand Valley, Colorado is about :27 metric tons per
hectare (12 tons/acre). Runoff at the Edna site was abnormally high dur-
ing the period of this study and the above quantities are not representa-
tive of the average condition, Additional water quality and quantity
measuring stations are being established at the Edna site, and the above
figures will be continually refined through June, 1976.
Estimated average annual salt pickup rates for the Edna and Navajo spoils
are 5.5 metric tons per hectare per year (2.4 tons/acre/yr) and 1.4
metric tons per hectare per year (0.6 tons/acre/yr), respectively. The
net additional salt pickup caused by mining at the Navajo site is signifi-
cantly lower than the above figures because the natural surface and sub-
surface runoff contains a relatively high concentration of dissolved
solids. The potential net additional salt pickup caused by mining at
the Edna Mine is not known precisely because the salt production from
the watershed above the mine is derived from geologic materials that
are not the same as those forming the spoil banks. Salt production from
the Edna spoils per unit area is more than 10 times greater than the
salt production from the upstream watershed, however.
Because of the difficulties involved in making accurate estimates of the
average annual surface and subsurface runoff, the average annual salt
pickup rates reported above should be regarded only as indications of
the magnitudes of average salt loading. The normalized salt pickup rate
(mass of salt per unit area per unit of surface and subsurface runoff)
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used for the Navajo Mine was calculated from the results of saturated
paste extracts and was not verified by direct measurement due to limita-
tions of time and budget. The salt pickup rate for the Navajo Mine is
expected to vary over a range corresponding to the range of spoil vari-
ability. The configuration of the graded spoils at the Navajo Mine
precludes significant quantities of surface runoff beyond the boundaries
of the disturbed area, and the estimated salt pickup refers to deep per-
colation (subsurface runoff). Given that our estimates of subsurface
runoff are reasonable and that the existing groundwater was highly mineral-
ized prior to mining, the pollution potential of the Navajo spoils must
be regarded as very low. Reclamation procedures involving spoil manipula-
tion and revegetation, currently being researched and practiced by Utah
International, should result in a return to the atmosphere of essentially
all incident precipitation.
A reliable, and probably conservative, index of the potential salt pro-
duction from the spoils studied is obtained by chemical analyses of sat-
urated paste extracts. The concentration of salts present in the extracts
from Edna samples, when combined with runoff volumes, resulted in a cal-
culated salt pickup rate that agreed very closely with the measured value.
Order of magnitude estimates of salt loading from a proposed mining site
can be made from extract analysis of overburden core samples and hydro-
logic information prior to mining activity. Optimum placement of spoils
for salt pickup control can also be judged from a saturated paste extract
analysis.
Some significant heavy metal concentrations were observed in the San
Miguel River at the Telluride site, where the mining and milling of a
copper-lead-zinc ore is in progress. Principal among them are manganese,
lead, and zinc. A portion of these are contributed by the tailings dis-
posal area, but a variety of old mines and mine dumps, scattered through-
out the watershed, also make a contribution. Equilibrium chemistry pre-
dicts smaller concentrations of these metals than observed in some ground-
water and stream samples.
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A total increase of 149 metric tons of dissolved solids was observed be-
tween the monitoring stations upstream and downstream from the active
tailings pond during the months of October, November, May and June. The
most likely source of these dissolved solids is the tailings transport
water, and not a dissolution of salts from the tailings material. The
ions with the largest observed concentrations in the stream were calcium,
magnesium, sodium, and sulfate. These ions, plus chloride, also dominate
the chemical makeup of the tailings transport water. The quality of tail-
ings' percolate corresponds to that of the transport water very well.
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SECTION II
RECOMMENDATIONS
Significant levels of nitrates were observed in the saturated paste ex-
tracts of the coal mine spoils investigated but it is not known if nitrates
represent a significant water pollution potential. It is recommended that
research into the origin, magnitude, and mobility of nitrates be persued.
The mechanisms by which heavy metals reach and maintain the concentrations
observed in this study at the Telluride site deserves further investi-
gation. Similar, unexplained observations have been made by other investi-
gators .
A program should be undertaken, in which , a detailed survey of current
and projected strip mining the the Upper Colorado River Basin is made.
The location, geology, hydrology, and areal extent of each operation and
projected operations should be inventoried. Where possible, saturated
extract analyses of overburden samples should be made. The result would
be a set of data, from which, the total salt load increase as a result
of mining in the basin could be projected. Such a projection is needed
to ascertain the significance of the problem so that an appropriate
national priority can be established.
A mathematical model of the process of salt pickup from mine spoils,
including the important geochemical and hydrological aspects, should be
developed and verified. The model would be an efficient tool for deter-
mining salt loading as a function of time and for studying the effective-
ness of various abatement procedures. Projections of salt loading on a
watershed scale under different management and mine location alternatives
could also be obtained from the model.
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SECTION III
INTRODUCTION
BACKGROUND
The basic underpinning of mankind's struggle for survival and his ability
to attain an acceptable standard of living resides directly in two funda-
mental activities: the agricultural and mineral industries. Society's
dependence on the products of agriculture is well understood and obvious
relative to that of the mining industry. Rarely is one reminded that
the mining industry provides the mineral fertilizers essential to the
production of the food and fiber so readily associated with the agricul-
tural industry. The transformation of the raw products of mining is,
often, so drastic that society does not readily recognize or appreciate
that mining is the first essential step in the transmission of electricity,
the construction of railroads, the production of concrete, the mainten-
ance of potable water supplies, the processing of food, the fabrication
of dental equipment and televisions, and a host of other activities.
The electrical energy used to heat and operate factories and homes bears
no resemblance to the coal from which it was produced. Nevertheless,
raw fuels, metals, and nonmetals, the value of which comprises only 3
percent of the Gross National Product, have a direct impact on 40 per-
cent of the national economy and an indirect impact on an additional
35 percent.
Since mining is an extractive industry, the potential for adversely
affecting land and water utilization by other industries, agriculture,
and municipalities is large. For example, numerous cases of water qual-
ity degradation caused by the production of mineral acids and sediment
from strip-mine spoils in the eastern United States can be found. Land
use is effected by the removal of vegetation and top soil, the exposure
of toxic geologic materials, the creation of unstable slopes, erosion,
and the change in aesthetic value. Many, if not most, of these potential
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side effects of mining have been largely ignored by the industry and
society, alike, until recent years. The intrinsic importance of mining
and the recognition of environmental quality as an essential component
in the social value system, now call for an appropriate balance between
economic mining and resource conservation and protection. Responsible
elements of society and industry have responded as evidenced by the
research and technology now being applied to problems associated with
mining in the eastern portion of the nation.
There exists relatively little documentation concerning potential land
use and water quality problems associated with mining in the western
states. Most of the western states receive much less precipitation than
those located in the East and Midwest, and therefore, the effect of
mining activity on the quantity and quality of water is a highly import-
ant consideration. Impairment of water quality in western rivers may
have a direct economic impact on downstream users. This is particularly
true of the Colorado River and its tributaries in which salinity has
reached levels of national and international concern. The seven basin
states sharing the water resources of the Colorado River and the Environ-
mental Protection Agency have adopted a non-degradation policy designed
to maintain the salinity in the lower basin at, or below, the current
level. Without a basin-wide salinity control program, it is estimated
that California, alone, will incur annual damages of $40 million by the
year 2000.
Other potential problems associated with large scale mining in the west
include the effect on stream biota, release of heavy metals or other
toxic elements to the receiving waters, sediment production, and the
change in the surface and subsurface hydrologic characteristics of the
watershed. All of the above aspects remain less than adequately research-
ed, and undoubtedly, many of them will be found to be insignificant.
Even methods for revegetation of strip mine spoils and tailings disposal
areas in the arid and semi-arid west have not been developed to the point
of routine application; notwithstanding the significant progress that
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has been made.
Water pollution potential, land use, revegetation, reclamation, erosion,
slope stability, etc. are all mutually inter-dependent variables. Fur-
thermore, they are functions of the geologic, hydrologic, and meteor-
ologic environment, and it is only through a thorough understanding of
the physical and chemical characteristics of the spoil materials, the
surface and subsurface hydrology, and the meteorology that rational
conclusions and recommendations can be drawn.
PURPOSE AND SCOPE
The purpose of this study was to identify potential water quality problems
associated with the runoff and percolation through mine spoils at selected
sites in the Upper Colorado River Basin, and to provide a quantitative
description of the interactions among geological, chemical, hydrological,
and meteorological variables influencing potential water quality degrad-
ation at these sites. Three sites were selected: the Navajo Mine near
Fruitland, New Mexico; the Edna Mine near Oak Creek, Colorado; and the
Idarado Mine near Telluride, Colorado. The first two sites are located
on the spoils produced by surface coal mining operations and the third
is located on the mill tailings associated with the mining of a lead-
zinc-copper ore. The hydrology, geology, and topography at each site
are significantly different, providing a wide range of conditions for
study and a partial basis for generalization of results.
The approach used to assess the water pollution potential of the spoils
is based on the premise that the potential is directly related to the
availability of both water and pollutants within the spoil banks. Spoil
samples were collected and analyzed in the laboratory and leaching tests
were made. These data are indicative of the quantity and type of contam-
inants that are readily available in the spoil banks. Estimates of the
quantity of water required to leach the contaminants were made from the
column tests. Analyses of available hydrologic and meteorologic data
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were conducted and related to the quantities of water available for
leaching the spoils.
At the Edna and Telluride sites, water quality monitoring stations were
established in the receiving streams and groundwater aquifers to identify
the type of contamination that occurs and to measure the degree of degrad-
ation. Samples were collected monthly and subjected to chemical analyses.
In addition, several gaging stations were constructed and calibrated to
provide surface-water discharge data which were used in the interpreta-
tion of observed water quality changes and to calculate contaminant dis-
charges. The in-stream data are correlated with the chemical analysis
of the spoils to show their relationship. Limitations of time and budget
made it necessary to restrict the scope of the investigation at the
Navajo site to making a limited number of infiltration tests and analyses
of spoil and overburden.
The data and analyses outlined above provide a rather detailed descrip-
tion of the current and potential water quality impairment attributable
to the spoils studied. The influence and relationships identified among
several geological, chemical, hydrological, and meteorological character-
istics constitute the first important step toward an in-depth comprehen-
sion of the systems under consideration, notwithstanding several observ-
ations that are not well understood at this time. The necessarily limited
scope of this one-year study prevented the in-depth investigation of
several potentially important observations and the refinement of many
measurements and estimates to the degree desirable. Continuing study of
several of these aspects is under way by the authors and other investi-
gators.
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SECTION IV
GEOLOGIC-HYDROLOGIC PERSPECTIVE
NAVAJO MINE
The Navajo Mine is located in the northwest corner of New Mexico immed-
iately south of the village of Fruitland (figure 1). The mine is a
surface coal mine operation situated on an outcrop of the Fruitland
formation near the western edge of the San Juan Basin in San Juan County.
The Fruitland formation is an Upper Cretaceous sequence of interbedded
sandstone, siltstone, shale, carbonaceous shales and sandstones, and
coal (Fassett and Hinds, 1971). The interbedded units are almost entirely
discontinuous, with most individual beds pinching out in a matter of a
few hundred meters. The exceptions are the coal beds which are continu-
ous over several miles in some instances.
The outcrop on which the mine was started is near the western edge of
the Hogback Monocline, which dips to the east at about 3 percent. Thus,
the coal beds, some of which have been exposed by erosion at the outcrop,
become progressively deeper to the east. The Kirtland shale, composed
of upper and lower units of gray shale separated by the Farmington sand-
stone member, conformably overlies the Fruitland rocks and forms addi-
tional overburden to the east of the present mining operations. Immed-
iately to the west of the mine, the Pictured Cliff sandstone formation
outcrops below the Fruitland formation. This sandstone, characterized
by one or more massive sandstone beds in the upper portion, is in con-
formable contact with the Fruitland sequence. The Pictured Cliff sand-
stone is underlain by the Lewis shale, a marine deposit consisting of
light-, to dark-grey, to black shales with interbedded sandstone and
silty limestones.
The Pictured Cliffs sandstone is the result of shallow-water and beach-
sand deposits formed by the final retreat from the San Juan Basin of a
10
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ARIZONA
FARMINGTON
KIRKLANO
Figure 1. Location of the Navajo Mine.
11
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Cretaceous epeiric sea that extended from the Arctic Ocean to the Gulf
of Mexico in late Cretaceous time. This epeiric sea divided the North
American continent into eastern and western land masses and covered most
of the Rocky Mountain and Great Plains states, as well as portions of
the Gulf states. Coastal swamp, river, flood plain and lake deposits
were laid down on top of the Pictured Cliffs as the sea regressed. These
materials now form the Fruitland formation. Vegetal matter accumulated
in the shoreline swamps and was subsequently covered by river deposits.
The accumulated vegetal matter comprises the coal beds in the Fruitland
rocks.
The climate at the Navajo Mine, at an altitude of 1550 m (5100 ft), is
arid with an average annual precipitation of 17 cm. The mean monthly
temperature in January is -1°C and during July is 25°C. The mean daily
minimum and maximum temperatures in January are -8°C and 6°C, respectively.
In July the mean daily minimum and maximum temperatures are 16°C and 33°C,
respectively. The estimated average annual potential evapotranspiration
by grasses is 103 cm; a quantity which exceeds the average annual pre-
cipitation by 86 cm.
Groundwater occurrence in the mined area is erratic. Small bodies of
perched groundwater are encountered in the Fruitland rocks. The small
quantities and erratic occurrence are consistent with the local and dis-
continuous beds of this formation. Unconfined groundwater occurs, again
in small quantities, in the Kirtland shale to the east. The only
significant groundwater reservoir (in terms of size) is found in the
Pictured Cliffs sandstone below the Fruitland formation. Water quality
in this reservoir was extremely poor prior to mining. Small, local
accumulations of groundwater sometimes exist in shallow alluvial deposits
associated with the arroyos in the area.
The major drainage feature in the northwest corner of New Mexico is the
San Juan River which flows westward at the north end of the mined area
(see figure 1). Surface drainage from the mine lease is toward the west
12
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through the Chinde Wash, Cottonwood Arroyo, and Pinabete Arroyo to the
Chaco River. The Chaco River flows north along the west side of the
lease area and into the San Juan River. The mine lease is located with-
in the eastern limb of the Chaco River watershed which covers some
6 2
1.13x10 ha (4350 square miles; Rabinowitz and Billings, 1973). The
mean annual discharge of the Chaco River at the confluence with the San
Juan River is estimated to be approximately 2.22x10 m (1.8x10 acre-
feet) or nearly 2 cm (0.8 inches) over the entire watershed. The total
4
area within the mine lease boundary is approximately 1.3x10 ha (32,000
acres), or slightly over 1 percent of the Chaco River watershed.
EDNA MINE SITE
The Edna Mine is located on the extreme southeast edge of Twenty Mile
Park just northwest of Oak Creek, Colorado (figure 2). Coal is extracted
from the Wadge seam in the Williams Fork formation of the Mesa Verde
group. The Williams Fork unit is Upper Cretaceous in age but is some-
what older than the Upper Cretaceous Fruitland formation at the Navajo
Mine. The Lewis shale, which lies beneath the Pictured Cliffs unit in
the San Juan Basin, conformably overlies the Williams Fork unit in north-
west Colorado. At the Edna Mine, the Lewis shale has been eroded away,
and the overburden materials are of the Williams Fork formation. Bass,
et al. (1955) describe the lower unit of the Williams Fork, in which
the Wadge seam is located, as consisting chiefly of shale, thin sand-
stone beds and sandy shale.
Present mining operations are being carried out on the eastern limb of
the Argo syncline (Cammpbell, 1923). The dip of the formations is to-
ward the west at approximately 10 percent. The topographic surface
strikes to northeast parallel to Trout Creek and, also, dips to the west
toward the stream at about 10 percent. Trout Creek flows generally
north at the foot of the mined slope. The coal is exposed by stripping
the overburden, resulting in a series of spoil ridges oriented parallel
to the strike of the slope. The spoils are presently being regraded
13
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STEAMBOAT SPRINGS
COLORADO
Figure 2. Location of the Edna Mine,
14
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to approximate original contour.
The climate at the Edna Mine contrasts markedly with that at the Navajo
Mine. The Edna spoils are located between the elevations of 2160 m
(7100 feet) and 2380 m (7800 feet) above mean sea level. The mean annual
precipitation at the mine is estimated to be 51 cm; about one-half of
which occurs in the form of snow. The coldest month is January and the
warmest is July. The estimated annual potential evapotranspiration by
grasses at the Edna Mine is 93 cm. The potential evapotranspiration
exceeds the precipitation by some 42 cm on an average annual basis.
Trout Creek, which flows generally north at the foot of the mined slope,
is the major surface drainage in the area. The stream has eroded a
shallow canyon in the Williams Fork rocks as evidenced by nearly vertical
outcrops of the formation on both sides of the stream below the spoils.
Shallow alluvium occurs along the stream bed and forms a local alluvial
aquifer. The lateral extent of this aquifer, in directions perpendicular
to the stream, is limited by the "bed rock" outcrops formed by the stream
erosion. Groundwater occurrence in the undisturbed Williams Fork is
limited to local fracture storage as evidenced by an almost dry mining
operation.
The Trout Creek watershed, above and including the Edna Mine, is approxi-
mately 1.1x10 ha (43 square miles). The mean annual discharge of Trout
73 4
Creek, just downstream of the mine, is estimated at 2.8x10 m (2.3x10
acre-feet), or nearly 26 cm (10 inches) over the portion of the water-
shed above the mine. The total disturbed area at the Edna Mine is
approximately 597 ha (1475 acres), or slightly more than 4 percent of
the total watershed area upstream of the mine.
IDARADO MINE SITE
The Idarado Mine is an underground mine in the San Juan Mountains near
the head waters of the San Miguel at Telluride, Colorado (figure 3).
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COLORADO
Figure 3. Location of the Idarado Mine.
16
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The San Juan Mountains form the southwest limit of the Colorado mineral
belt; a long, narrow corridor that extends diagonally across the mountains
from Boulder County to southwestern Colorado. The belt is characterized
by porphyries and associated ore deposits throughout its length (Tweto
and Sims, 1963). The porphyry materials are, largely, Tertiary in age,
being formed during the Laramide orogeny by intrusion along a zone of
Precambrian shearing that forms the limits of the mineral belt. The
Laramide orogeny occurred in Late Cretaceous and Early Tertiary time and
simultaneously with the retreat of the Cretaceous epeiric sea, with which
the formation of the sedimentary Fruitland rocks in New Mexico and the
Mesa Verde group in Colorado are associated.
The San Juan Mountains are not the direct result of the Laramide mountain
building period, however. Rather, they were formed in Late Tertiary time
by extensive volcanic eruptions after the Laramide orogeny had drawn to
a close. It was. at this time that the valuable ore deposits were formed.
The present day sharp peaks, deep canyons, shear cliffs, and steep-
walled valleys are the result of subsequent glaciation that occurred
during the Pleistocene. Ore deposits in the Telluride District normally
occur in chimneys, breccia veins, and fissure veins in the volcanic
rocks near the edge of the Silverton caldera.
Early mining activity centered around the extraction of precious metals
from the oxidized zones of the veins near their outcrops. Recoverable
base metals became increasingly important with depth, and today, profit-
able operations depend, almost entirely, on base metal production. The
Idarado ore is composed mainly of galena, chalcopyrite and sphalerite,
from which lead, copper and zinc are extracted. The mine consists of a
complex system of interconnected drifts, stopes and shafts resulting
from a consolidation of several old mines dating back 100 years. The
lowest level of the mine is some 885 m (2900 feet) below ground surface.
A variety of stopes, drifts, tunnels, and natural fractures intersect
the surface, permitting significant quantities of runoff to enter the
mine workings. Portions of the mine drainage are discharged into small
17
-------
streams, immediately tributary to the San Miguel River.
An average of 1.5x10 kg (1650 tons) of ore are processed each day at
the Pandora Mill on the San Miguel River at Telluride. Mill tailings
in the amount of 1.41x10 kg (1550 tons) are transported in 4.2x10 m
(1.49x10 ft ) of water to tailings ponds each day. The tailings ponds
are located adjacent to the river where the solids in the slurry have
formed large spoil banks. The transport water and incident precipitation
evaporates and percolates downward through the spoils. Over the years,
six separate tailings ponds have been formed which are, now, largely
contiguous with one another.
The Idarado study area is located at an elevation of 2740 m (9000 feet)
in a glacial cirque. The site is surrounded on three sides by towering
mountains and sheer cliffs rising to elevations of more than 4000 m
(13,000 feet). The mean monthly temperature during January, the coldest
month, is -6°C, and the warmest month, July, has a mean temperature of
15°C. The mean annual precipitation is 61 cm (24 inches) at Telluride,
approximately 50 percent of which occurs as snow. The mean annual
snowfall in the mountains immediately surrounding Telluride is 5.1 m
(200 inches). The potential evapotranspiration for grasses at Telluride
is calculated to be 84 cm (33 inches).
The major drainage features are the San Miguel River and its tributaries:
Bridal Veil Creek, Marshal Creek, Bear Creek, and Ingram Creek. All of
these tributaries enter the river within or above the study area. The
mean annual discharge of the San Miguel at Telluride is estimated to be
734 4
4.56x10 m (3.7x10 acre-feet) from a watershed of 1.1x10 ha (43 square
miles). This is equivalent to a runoff of 42 cm (16.5 inches) over the
entire watershed above Telluride. The tailings pond spoils have a sur-
face area of approximately 43 ha (85 acres), or only 0.3 percent of the
upstream watershed area.
18
-------
SECTION V
FIELD AND LABORATORY INVESTIGATIONS
FIELD STUDIES
This section contains a description of the field experiments and proced-
ures used at each site. These include water quality sampling, spoil
sampling, infiltration tests, discharge determinations, and groundwater
observation well installation. Also included are descriptions of the
sample designation codes and locations.
Water Quality Monitoring
Eight surface water quality monitoring stations were established at the
Edna site. Five of these points are in-stream stations on Trout Creek,
and three were specifically located to sample water directly from the
mined area. The locations of the sampling points and their designations
are shown in figure 4. Station Cl is located in Trout Creek upstream of
all coal mining activity in the area, and thus, provides baseline data
to which downstream water -quality can be compared. Station C2 is also
located in Trout Creek, 1.9 km downstream of Cl. One small-scale under-
ground coal mine is located near the stream between points Cl and C2.
Water which has percolated through and over the older, "knock off graded"
spoils to the is sampled at station C3 where it collects behind
and highwall of the box cut at the foot of the mined slope. There is a
spill point, over which, water flows into the stream. Sample station C4
is on Trout Creek below the southwest mined area but above the northeast
portion. Two small tributary drainage ways join Trout Creek between
stations C2 and C4; both on the mine spoil side of the stream. Station C5
is on a small drainage way, leading directly from the northeast spoil
area. This area has been regraded to the approximate original contour.
Point C6 was established on the stream immediately above an irrigation
19
-------
I
/
SCALE: KILOMETERS
r~
Figure 4. Edna Mine spoils, Trout Creek,
and water quality monitoring stations.
20
-------
diversion point. Groundwater seepage from the mine was sampled at sta-
tion C7 on the seepage face formed by the intersection of the water table
with the stream bank, In-stream station C8 was established in an attempt
to detect differences in water quality caused by the groundwater influent
between stations C6 and C8. Groundwater samples were collected at an
observation well and designated CP1. The location of this well is also
shown in figure 4.
No water quality monitoring program was established at the Navajo site
because surface flows are intermittent and groundwater in significant
quantites was too deep to study within the scope of this project. There
are a few data on water quality, available from other sources, that will
be used later in this report.
During the first month of sampling at the Idarado site, a total of 22
water samples were collected. Based on the analysis of these samples,
the number of sampling stations was reduced to thirteen; eleven surface
stations and two groundwater stations. The locations of the first nine
surface water sampling points are designated by Tl through T9 and are
shown on the map of figure 5. Station T10 is located on the San Miguel
at the confluence of the South Fork, several kilometers downstream of
Telluride. Station Til is on the river at Placerville, Colorado near
the U. S. Geological Survey stream gaging station.
Station Tl is located just below the confluence of Ingram and Bridal Veil
Creeks above all Idarado operations on the stream. Many old mine workings
exist above the Tl station, however, and the water quality .cannot be
considered representative of that which would exist in the total absence
of mining activity. Samples collected at T2 are mine drainage samples.
Station T3, on Marshal Creek, also samples mine drainage after dilution
with normal stream water. Stations T4, T7, T8, and T9 are located on
the river. Station T5 is on Bear Creek, and water from this sampling
point is used as the datum for comparing water quality. Seepage through
the tailings pond spoils was monitored at station T6 from a drain pipe
21
-------
I I
I I
SCALE: KILOMETERS
/I Q I
Figure 5. Idarado Mine, San Miguel River and tributaries, and water quality monitoring stations
-------
and at two observation well stations; TP3 and TP8.
Beginning in October, 1973, samples were collected monthly at the above
described stations. These samples were treated and analyzed in accordance
with EPA procedures. Some difficulty with sampling was experienced from
time to time. During the winter months, the water in piezometers was
often frozen, making it impossible to collect a sample. Thick ice cover
on the streams made it necessary to collect samples through holes, chopped
in the ice with an ax. It was sometimes discovered that the water was
frozen all the way to the stream bed, in which case it was necessary to
move downstream a short distance and repeat the attempt to find water.
It was not uncommon for water samples to freeze in a short time following
their extraction. Nevertheless, a reasonably complete set of water
quality data for the period October 1, 1973 through July 1, 1974, was
generated for both the Edna and Idarado study sites.
Discharge Monitoring
Three discharge measuring stations were established at the Edna site.
The upstream station on Trout Creek was set up at quality monitoring
station C2 (figure 4) above the portion of the watershed in which the
spoils are located. The stream discharge was measured by determining
the velocity distribution in the cross-section with a current meter.
The corresponding water stage was noted from a staff gage that was con-
structed at a convenient location on the cross-section. These data,
repeated at different stages, together with measurements of the dimensions
of the flow section permitted the construction of an approximate stage-
discharge relationship. A similar procedure was used to estimate the
discharge at the C6 location (figure 4) just- above an irrigation diver-
sion point. The discharge from the boxcut at station C3 was also meas-
ured. This was accomplished by installing a 30 cm (12 inch) Parshall
flume at the spill point.
Procedures, similar to those used at the Edna site, were used to estimate
23
-------
the discharges at several locations at the Idarado site. These include
the mine drainage at station T2 (figure 5), Marshal Creek (T3), Bear
Creek (T5) and the San Miguel River at two locations (T4 and T8). The
appropriate stage measurements at each station were taken monthly at the
same time water quality samples were obtained. Difficulties with thick
ice and deep snows made it impossible to obtain a complete record of
discharges at some locations, and also influenced the accuracy of the
discharge estimates. The significance of both the discharge measurements
and their inherent errors are discussed in a subsequent section of this
report.
Groundwater Monitoring
Several observation wells were installed at strategic locations at both
the Edna and Idarado sites. The wells consist of a 3.2 cm (1^ inch)
galvanized pipe casing with a screened well point (sand point) on the
lower end. Several feet of pipe were extended above the ground surface
for easy location and access in deep snow. The pipe and well points were
installed in holes augered by a trailer-mounted boring unit. The annular
space between the hole wall and the pipe was filled with available soil
and cuttings. No attempt was made to completely seal the annulus with
an impermeable material. Thus, the well points act as observation wells
rather than piezometers.
Eleven wells were installed in the alluvium adjacent to Trout Creek be-
tween the stream and the toe of the spoil banks. The wells were installed
in areas where preliminary observations indicated groundwater influent
from the mined area. Eight wells were installed near the active tailings
pond at the Idarado site, and three wells already existing in the tailings
were incorporated into the network. The locations of the wells were
determined by a survey and plotted on appropriate maps. Arbitrary eleva-
tion datum points were established at both sites, and the elevations
(relative to the datum points) of each observation well were determined.
24
-------
The depth to water in the observation wells was measured monthly. These
data were then converted to water table elevations from which water table
maps showing the gradient and direction of groundwater movement were pre-
pared. The water table maps are presented in a subsequent section of
this report.
Infiltration Tests
Ten infiltration tests were performed in this study; four on the Edna site,
four on the Navajo site, and two on the Idarado site, Infiltration was
measured using the well known cylinder infiltrometer method. Open ended
cylinders, approximately 36 cm (14 inches) in diameter and 46 cm (18 inches)
long, were driven into the material to be tested to a depth of at least
15 cm. A berm was constructed around the cylinder at a distance of approxi-
mately 20 cm (8 inches). A staff gage was installed inside the cylinder,
and a sheet of plastic was placed so that the soil surface and the inside
surface of the cylinder were completely covered. Water was poured into
the cylinder on the plastic to a depth of about 15 cm. When all was in
readiness, the plastic sheet was slowly and carefully removed, allowing
infiltration to begin. Simultaneously, the moat around the outside of
the cylinder was filled with water. The depth of water in the infil-
trometer was recorded as a function of time to obtain the cumulative
infiltration curve.
At the Edna and Navajo sites, infiltration curves were measured for both
graded spoils and undisturbed soil. Revegetated tailings and fresh tail-
ings were tested at the Idarado site. Infiltration was allowed to proceed
until the intake rate appeared to be constant. The final constant rate
can be taken as an approximate measure of the hydraulic conductivity of
the materials in an undisturbed state. Downward and lateral spreading
of the wetted volume by capillary pressure gradients that still exist,
even after long periods of time, cause the hydraulic conductivity estim-
ated by this method to be somewhat high. It is believed that this dis-
advantage is far outweighed by the advantages of making the tests in the
25
-------
field on relatively undisturbed material, however.
Spoil Sampling
Spoil samples to be used for physical and chemcial characterization were
collected at eight locations of the Edna spoils. Samples were taken
every 15 cm (6 inches) of depth from the surface to a depth of 120 cm at
three locations on the extreme north end of the mined area (see figure 4).
Samples from the up-slope limit of mining are denoted by NSI, from near
mid-slope by NSII, and from the foot of the slope by NSIII. The depth
interval for each sample is appended to the above location code. A
similar procedure was used to collect and code samples in the spoils
immediately east of station C4 in figure 4. These samples were given the
code MSI, etc.. Samples from the older spoils south of station C3 in
figure 4, were collected at two locations and given the designation SSI
and SSII, appended with the appropriate depth interval.
In addition to the above samples, native soil was collected at intervals
to a depth of a meter at one location. Also, a number of drill cuttings
were sampled along the active highwall. This was accomplished by collect-
ing a drill sample in every 3 m interval from the surface to the coal
seam at four locations along the active high wall. These samples were
subsequently composited by depth interval and designated as DC with the
appropriate depth interval appended.
The approximate locations of the sampling sites on the Navajo Mine are
indicated in figure 6. Samples designated by R-l through R-6 were
collected on an east-west line, traversing a series of ungraded spoil
ridges ranging in age from June, 1973 to September, 1970. These samples
are all surface samples. Sample R-l is the youngest and R-6 the oldest
spoil material in the three year time interval.
Overburden samples were collected on the high wall in the Hosteen Pit in
approximate 1.5 m intervals from the surface to the top of the uppermost
26
-------
MORGAN
LAKE
INFILTRATION
TESTS
OVERBURDEN
SAMPLES
SCALE .-KILOMETERS
fl
Figure 6. Approximate spoil sample
locations at the Navajo Mine.
27
-------
coal seam (No. 6 seam). Seams numbered 7 and 8, which normally occur
above the No. 6 seam, are not present in the Hosteen Pit. A total of
eleven overburden samples were collected in approximate 1.5 m intervals
from the soil surface to the top of the No. 6 seam in the Barber Pit.
At this location, seams No, 7 and 8 are present above the No. 6. Thus,
the partings between the No. 8 and No. 7 seam and between the No. 7 and
No. 6 seam were sampled. The material in the latter parting is the sur-
face material after stripping.
Samples of the tailings at the Idarado site were collected from each of
the six tailings ponds, A trailer-mounted boring unit was used to col-
lect samples in 15 cm intervals over depths ranging from 1.5 m to 7 m.
The most extensive areal distribution of sampling was conducted on tail-
ings pond No. 6. Deep sampling was accomplished at ponds No. 1, 2, and
5. The first number in the sample code indicates from which pond the
sample was extracted. The second set of numbers designates the depth
interval.
LABORATORY STUDIES
A variety of laboratory tests and experiments were performed during the
course of this study. These include water analysis, spoil sample analysis,
and leaching experiments. The pertinent features of the experiments and
procedures are described in the following paragraphs.
Water Analysis
Water samples were analyzed for: total acidity and alkalinity, total
hardness, pH, specific conductance, suspended solids, total dissolved
solids, total solids, and concentrations of aluminum, calcium, chloride,
copper, dissolved iron, undissolved iron, total iron, potassium,, magnesium,
manganese, sodium, lead, sulfate, and zinc. These determinations were
made on 22 water samples collected each month from the locations pre-
viously described. All samples were collected and treated in accordance
28
-------
with the standard Environmental Protection Agency "Methods for Chemical
Analysis of Water and Wastes" (U, S, Department of Interior, 1970). Those
analyses and sample treatment steps which were designated by this manual
for completion within 24 hours after collection were accomplished in the
field, and those which must be completed within seven days were accom-
plished immediately upon return to the laboratory. The samples for all
other analyses were stored under the conditions stipulated in the manual.
Usually, all analyses were completed within two months after collection.
Spoil Analysis
Based on the assumption that the minimum pollution potential of the spoils
is best indicated by the quantities of water soluble cations and anions
present, the saturated paste method was used to chemically characterize
the spoils and overburden. It was recognized that such factors as
weathering, microbial activity, acid formation, cation exchange capacity
and nonequilibrium chemical reactions, among other factors, all influence
the pollution potential of spoils in ways not characterized by the sat-
urated paste method. Preliminary tests of leachate and surface water
samples indicated, however, that the saturated paste analyses should
account for the observed contaminants in these water samples. The
expected correlation between the major constituents of the saturated
pastes and those observed in field water samples was subsequently veri-
fied and will be discussed in a following section of this report.
The procedures used in the saturated paste method are described in detail
by Hergert (1971a). The sample is first completely dried and then the
material is reduced in size to the point where it will pass a 2 mm (ten
mesh) screen. The sample is saturated with distilled water, thoroughly
mixed, and allowed to stand for 16 hours. The saturation percentage is
determined on a portion of the sample by normal gravimetric techniques
and the water is extracted from the remainder of the sample. The extract
is then subjected to a variety of analyses for the chemical constituents.
In this study, determinations of pH, specific conductance, calcium,
29
-------
magnesium, sodium, potassium, carbonate, bi-carbonate, chloride, sulfate
and nitrate were made. The concentrations of the ions are reported as
mass of the particular species per million parts (by weight) of the
extract.
Standard plant nutrient analyses were also performed on spoil and over-
8
burden samples. The details of the procedures are given by Hergert (1971b)
Concentrations reported in the plant nutrient analysis are reported as
the mass of particular nutrient per million parts (by weight) of soil.
Leaching Experiments
Leaching tests were conducted with the two-fold purpose of estimating
the total quantity of removable salts in the spoils and of determining
the relationship between salt removal and water through-put volume. These
tests were conducted by passing distilled water downward through columns
of spoil, collecting the leachate in increments and measuring the specific
conductance of each increment. The columns were approximately 30 cm long
and the through-put rate was maintained equal to or below the hydraulic
conductivity of the material in each column. A total of thirteen columns
were subjected to leaching; 3 columns of Navajo Mine overburden, 3 columns
of Edna Mine spoils, 3 columns of Edna drill cuttings and 4 columns of
tailings from the Idarado site. A sample from each column was subjected
to the saturated paste analysis to provide data on initial conditions.
30
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SECTION VI
WATER QUALITY AND RELATION TO SPOIL CHARACTERISTICS
This section of the report is devoted to a presentation and discussion
of the observed water quality and its relationship to the chemical char-
acteristics of the spoils. Only the salient features of the data,
pertinent to this discussion, have been extracted. Liberal use has been
made of averages, summaries, and indicative parameters (such as total
dissolved solids and specific conductance). Complete and detailed sets
of data are tabulated in the appendices.
EDNA MINE SITE
Chemical Degradation
An example of the analysis of in-stream water samples on Trout Creek at
the Edna site is presented in Table 1. Average results have little
meaning, in this case, because of the variation from month to month over
the sampling period and with location with respect to the spoil banks.
The data in Table 1 is for the month of April, 1974, and for the sampling
station immediately downstream of the spoils. Thus, Table 1 contains
the data for the time and location at which the poorest water quality
was observed. Public Health Service drinking water standards are also
included in Table 1 for perspective. Note that soluble salts are appar-
ently the major contaminants.
The observed water quality in the streams varied significantly with both
location and time, particularly at the Edna site. Figure 7 shows the
measured water quality (as indicated by specific conductance) profiles
along Trout Creek at the foot of the mined slope. No significant water
quality deterioration was observed between stations Cl and C2. There
is no surface mining nor irrigated agricultural land between these sta-
tions.
31
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Table 1. APRIL, 1974, WATER QUALITY ON TROUT CREEK.
Parameter
Acidity, mg CaC03/Jl
Alkalinity,mg CaC03/Jl
Total hardness, mg/£
Specific cond..,umohs/cm
Total dissolved solids, mg/Jl
Suspended solids, mg/Jl
Total solids, mg/Jl
pH
Aluminum, mg/Jl
Calcium, mg/Jl
Chloride, mg/Jl
Copper, mg/Jl
Dissolved iron, mg/Jl
Undissolved iron, mg/fc
Potassium, mg/Jl
Magnesium, mg/Jl
Manganese, mg/Jl
Sodium, mg/Jl
Lead,mg/Jl
Sulfate,mg/Jl
Zinc, mg/Jl
Trout Creek
station C8
<1
120
470
894
660
6
666
7.8
<0.5
210
1.9
<0.1
<0.05
-
3
49
0.04
17
<0.14
250
0.017
U. S. drinking
water standards
-
-
-
-
500
-
-
8.0
-
-
250
1.0
0.3
-
-
125
0.05
-
0.05
250
5
S. Public Health Service (1962).
32
-------
1000
O-J
o
800
M
u
o
I
o
o
c
600
400
200]
J_
I 23456
DISTANCE DOWNSTREAM FROM STATION Cl, kilometers
APRIL
MARCH
FEB.
OCT.
8
Figure 7. Specific conductance profiles on an eight kilometer reach of Trout Creek.
-------
A very pronounced increase in conductivity occurs between stations C2
and C4, however. Surface and subsurface flows from the inactive spoil
area directly south of station C3 and from irrigated meadows on the
northwest side of the stream enter Trout Creek between stations C2 and
C4. An additional increase in specific conductance was observed in the
reach of stream between stations C4 (5.8 km downstream of Cl) and sta-
tion C8 (8 km downstream of Cl). There are relatively fresh spoils
immediately east of this reach (see figure 4), and irrigated meadows
to the west.
It is noted from figure 7 that the specific conductance increases by a
factor greater than two in the reach of stream investigated, and that
the relative increase becomes larger through the winter and early spring.
These results are more apparent in figure 8 which shows the specific
conductance at the upstream station C2 and at the downstream station C8
plotted as functions of time. The conductivity at C8 exhibits a gradual
increase between October and January, reflecting an increased fraction
of relatively poor quality groundwater during these months of nearly
base flow. The specific conductance of the groundwater at station C7
averaged 4105 \i mohs/cm for the nine month period.
The more pronounced increase in conductivity evident from January to
March is attributed to an even larger groundwater contribution, relative
to the surface water, as the surface water sources froze in the upper
reaches of the watershed. Discharge measurements at station C2 indicate
a significant reduction of the influx of dilution water from above the
study area during February and March and, presumably, during January.
The discharge at stations C2 and C3 are presented in Table 2.
Figure 8 shows that the specific conductance peaked in April and declined
sharply in May and June. This is a reflection of an increase in surface
and subsurface inflows from the study area relative to the quantity of
water from the upper reaches of the watershed. This is evident in Table
2 which shows that, during the first week of April, when the samples
34
-------
IOOO
E
o
800
o
E
°»600
eg
Ul
o
5 400
H
O
O
o
o
o
£
hi
0.
CO
200-
OCT NOV DEC JAN FEB MAR APR MAY
Figure 8. Specific conductance on Trout Creek for a nine month period.
-------
Table 2. DISCHARGE AND SPECIFIC CONDUCTANCE AT STATIONS C2 § C3.
Time
Oct,1973
Nov
Dec
Jan, 1974
Feb
Mar
Apr
May
Jun
Gage,
cm
15.0
14.0
18.5
-
12.0
13.0
13.0
53.5
58.0
Station C2
Discharge,
m3/sec
0.37
0.31
0.56
-
0.22
0.26
0.26
4.45
5.32
Station C3
EC*,
pmohs/cm
65
164
187
187
211
240
200
209
147
Gage,
cm
-
4.6
4.3
4.6
4.3
4.9
10.7
>34.2
9.8
Discharge,
m3/sec
-
0.006
0.006
0.006
0.006
0.007
0.023
>0.134
0.020
EC3,
ymohs/cra
2450
2580
2510
2350
2200
2130
1890
2450
2400
Specific conductance at 25°C.
were collected, the stream flow at station C2 remained very close to the
normal winter discharge, while the surface and subsurface runoff from
the study area as indicated at C3, increased by a factor of three.
Unfortunately, the Trout Creek gaging station at C6 was disrupted in
January by ice, and a direct measure of the quantity of runoff from the
watershed between stations C2 and C8 is not available. The data col-
lected at station C3 is representative of both the timing and the qual-
ity of the mine discharge, however. The maximum observed runoff from
the spoil area was observed in early May and, undoubtedly, the maximum
contribution of salts from the study area occurred during the maximum
runoff period. This is not reflected directly in figure 8, however,
because of the dilution effect resulting from large discharges of better
quality water observed at station C2 in May (Table 2).
The results presented above leave little doubt that water quality degrad-
ation occurs in the reach of stream investigated, but there remains a
question concerning the actual increased contribution caused by the mine
36
-------
spoils. It is observed from figure 8 and Table 2 that the specific
conductance at station C2 did not change greatly from April to June; a
time period, over which, the discharge at C2 increased several fold.
This observation indicates that the water produced on the upper reaches
of the watershed does not pick up an appreciable salt load from the un-
disturbed soils found there. The soils in the portion of the watershed
immediately above the study area are derived from the lies member of the
Mesa Verde group (Bass et al., 1955), however, and the fact that no
appreciable salt loading was observed at C2 may not be indicative of the
quantity of salts that are derived from the undisturbed portion of the
Williams Fork formation in the study area. Therefore, the specific con-
ductance of surface and subsurface water entering the stream from the
west side (not mined) was measured at eight locations along the reach
between station C2 and C8. The specific conductance of the groundwater
samples from the west side averaged 504 y mohs/cm, with the highest
observed conductivity being 806 y mohs/cm. The conductivities of two
groundwater samples collected upstream of both the agricultural and mined
lands were 560 and 714 y mohs/cm. These numbers are to be compared with
the conductivity of groundwater on the east bank, directly below the
spoils, which averaged 4105 u mohs/cm. The specific conductance of sur-
face runoff from the agricultural land averaged 267 y mohs/cm.
There exists a general correspondence between the chemical characteristics
of the spoils and overburden at the Edna Mine and the chemical character-
istics of the runoff and groundwater. The average results from the sat-
urated paste analysis of 14 samples of spoils, 20 samples of drill cut-
tings, and one composite sample of native soil are given in Table 3.
Also included in Table 3 are the corresponding average results from
samples of runoff and groundwater. It is noted that the ions that are
dominant in the saturated paste extract are dominant in the water samples.
One significant anomaly exists, however. The calcium concentration in
the water samples is much larger than would be expected from the satur-
ated paste results. This observation will be discussed in conjunction
with the leaching experiments, but it remains largely unexplained.
37
-------
Table 3. AVERAGE CHEMICAL CHARACTERISTICS
OF SPOIL, RUNOFF AND GROUNDWATER.
Specific Ca Mg Na K Ci S04
Sample pH cond. ppm ppm ppm ppm ppm ppm
Edna spoils 8,0 3110 39 221 41 28 15 650
Edna drill 8.1 2970 38 162 83 39 31 544
cuttings
Edna native 8.1 340 3 9 13 11 20 30
soil
Station C3 7.6 2330 400 140 21 5 4 800
(runoff $ percol.)
Station C5 7.7 3025 363 225 80 18 4 800
(runoff § percol.)
Station C7 7.5 4105 312 168 541 14 8 800
(groundwater)
Table 4. SEDIMENT CONCENTRATIONS
AT STATIONS C2 AND C8.
Suspended solids cone en. , ing/ £.
Month
Oct
Nov
Dec
Jan
Feb
Mar
Apr
Station C8
3.9
1.4
M)
X0
M)
3.0
6.2
Station C2
2.4
1.4
^Q
2.2
'vO
'v.O
-vO
Net
1.5
0
0
-2.2
%o
3.0
6.2
38
-------
The correspondence observed between the results of the spoil analyses
and the water analyses does not extrapolate to the chemical character-
istics of the soil. The levels of calcium, magnesium and sulfate in the
spoil are less than one-tenth of the levels in the spoils, drill cuttings,
or water samples, and are of insufficient magnitude to produce the levels
of water quality degradation observed in the stream.
There are other indications that the spoils are the major cause of the
water quality changes observed. During October, a salt deposit was
observed along a 30 m reach of Trout Creek between stations C6 and C8.
The salt was the result of evaporation of groundwater on the seepage
face formed by the intersection of the water table with the stream bank.
A small network of observation wells was installed in the alluvium to
help determine the source of the groundwater. The measured water-table
elevations are the basis for the map of figure 9 which indicates the
direction of flow is from the mine, into the stream. Other groundwater
seeps near the toe of the spoil banks were noted from place to place.
Sediment Pollution
The concentrations of suspended solids at the upper and lower sampling
stations on Trout Creek are shown in Table 4. Data for the high runoff
months of May and June are not available at the time of this writing.
Since May and June are the months when the sediment concentrations are
expected to be highest, no conclusions can be drawn concerning sediment
loads.
Contaminant Loading
The magnitude of salt loads added to Trout Creek between stations C2 and
C8 were computed by combining the discharge and concentration data into
discharge rates for total dissolved solids. Because of the lack of dis-
charge measurements at station C8 after December, it was assumed that
the discharge at C8 was equal to that at C2. This assumption is probably
39
-------
CONTOUR INTERVAL =0-5m,
SCALE: METERS
0 5
27-5
10
Figure 9. Water table map near station C8.
-------
Table 5. DISCHARGE OF TOTAL DISSOLVED
SOLIDS AT STATIONS C2, C3 $ C8.
(metric tons/month)
Month
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
*»
Station C8
Qds
186
151
294
-
173
314
451
5610
2655
Station C2
Qds
55
130
177
-
64
75
82
1636
1537
Net
Qds
131
21
117
-
109
239
369
3974
1118
Station C3
Qds
39
39
36
36
35
37
118
>746
110
quite good from October to March, but will certainly result in an under-
estimate at C8 during the spring runoff. Thus, the calculated stream
loading is believed to be conservative.
The calculated discharges of total dissolved solids at stations C2, C3,
and C8 are given by month in Table 5. Using the February results for
January and adding the columns in Table 5 results in an estimated inflow
of salts equal to 3820 metric tons at C2 and an estimated outflow of
10,007 metric tons at station C8. The net pick up of salt load during
the nine month period is 6187 metric tons in the reach of stream between
C2 and C8. The quantity of dissolved solids added at station C3 is 1196
metric tons, or nearly 20 percent of the total. It is important to note
that more than 80 percent of the total load is contributed during the
spring runoff in April, May, and June.
The water at station C3 is composed of both surface and groundwater run-
off from the spoils immediately south of the station. It is estimated
that the maximum spoil area contributing at station C3 is 142 ha (350
41
-------
acres). Thus, the total salt load of 1196 metric tons measured at this
station translates to 8.42 metric tons per hectare or 3.7 tons per acre
for the nine month period. The corresponding quantity of surface and
groundwater runoff over the same area and time period is 40 cm (16 inches)
resulting in an average salt pickup rate of 0.21 metric tons per hectare
per centimeter of surface and groundwater runoff (0.23 tons/acre/in).
A review of the conditions under which the above numbers were derived is
important. The spoil area contributing to station C3 was mined during
the period from 1947 to 1962. A substantial portion was mined by
placing the spoils on undisturbed ground; thus, leaving ribbons of virgin
ground beneath the spoil banks. Both the age and the method by which
the spoils were handled tend to make their contribution to the salt load
somewhat smaller than from fresh spoils placed in the pit. The data
in Table 3 show that the station C3 water, indeed, exhibited a signific-
antly lower specific conductance than that measured at stations C5 and
C7 below the more recent spoils. Variability in spoil characteristics
could also account for this observation, however. The discharge measure-
ments at station C3 are believed to be quite accurate except for the
month of May when the Parshall flume was submerged by the large flows.
The maximum capacity of the flume, which was obviously less than the
flow, was used for the May calculation. The pond behind the high wall
at C3 dampens normal flucturations in the runoff hydrograph which helped
to obtain representative flow rates.
It is believed that the figures of 6187 metric tons of salt pickup, 1196
metric tons from the area south of C3, and the per hectare pickup of
8.42 metric tons are valid estimates, and probably somewhat conservative.
The 1974 spring runoff, however, was exceptionally large and definitely
cannot be considered normal. Since the total salt loading is highly
dependent upon the quantity of surface and subsurface runoff, it is
expected that the salt production from the spoils in a normal runoff
year is much less than that observed in this study. The normalized
figure of 0.21 metric tons of salt pickup per hectare per centimeter of
42
-------
surface and groundwater runoff is not sensitive to the magnitude of run-
off, however, and can be used to estimate total salt loads for other
runoff conditions. Estimates for normal runoff conditions are discussed
in a subsequent section of this report.
Unfortunately, there are no other data on salt loading from strip mine
spoils in the Rocky Mountain region to which the results of this study
can be directly compared. There are, however, estimates of salt loading
from irrigation return flows which help to place the above results in
perspective. Annual salt loading from irrigation return flow has been
estimated to be about 27 metric tons per hectare '(12 tons/acre) in Grand
9
Valley, Colorado (Skogerboe and Walker, 1972), which is roughly three
times the quantity estimated herein. The irrigated areas in Colorado's
Uncompahgre and Lower Gunnison River Valleys contribute an estimated
salt load of 13 metric tons per hectare (6 tons/acre) annually to the
streams.
IDARADO MINE SITE
An example of the analysis of in-stream water samples on the San Miguel
River is presented in Table 6. The variability in water quality with
time and location makes average results meaningless, and therefore, the
data set which indicates the poorest water quality appears in Table 6.
Again, the poorest water quality was observed at station T4 above the
point of dilution by Bear Creek but downstream of four tailings ponds.
Both the hydrology and potential sources of water contaminants are much
more complex at the Idarado site than at the Edna site, and it was not
possible to obtain a completely clear description of the influence of
the tailings piles. During the spring runoff, water enters the stream
almost everywhere along the reach investigated. It was possible to
determine neither the quality nor quantity of the runoff with sufficient
^curacy to prepare a dissolved solids budget for the entire reach of
investigated. It was possible, however, to calculate the dissolved
43
-------
Table 6. APRIL, 1974, WATER QUALITY ON THE SAN MIGUEL RIVER.
Parameter
Acidity, mg CaC03/Jl
Alkalinity, rag CaC03/Jl
Total hardness, mg/ A
Specific cond. ,umohs/cm
Total dissolved solids, mg/Jl
Suspended solids ,mg/Jl
Total solids, mg/Jl
PH
Aluminum, mg/fc
Calcium, mg/fc
Chloride, mg/Jl
Copper, mg/Jl
Dissolved iron, mg/Jl
Undissolved iron, mg/Jl
Potassium, mg/i
Magnesium, mg/jt
Manganese, mg/Jl
Sodium, mg/Jl
Lead, mg/Jl
Sul fate, mg/Jl
Zinc, mg/Jl
aU. S. Public Health Service
San Miguel River
station T4
2
36
250
468
370
-
-
7.7
<0.5
150
3.8
<0.1
<0.05
-
<1
5.9
0.72
6.9
<0.14
150
0.14
(1962).
U. S. drinking water
standards4
-
-
-
500
-
-
8.0
-
-
250
1.0
0.3
-
-
125
0.05
-
0.05
250
5
mineral pickup between stations T4 and T8 for the months of October,
November, May, and June.
The measured discharges, 0 , at stations T4, T5, and T8 are tabulated,
along with the corresponding dissolved solids concentrations, in Table 7.
Also included are the calculated discharges of dissolved solids, Q, .
44
-------
Table 7. DISCHARGE OF WATER AND, DISSOLVED SOLIDS AT STATIONS T4, T5 AND T8.
(metric tons)
L/1
Month
Oct
Nov
May
Jun
m^/sec
0.11
0.06
0.88
2.01
Station T4
Dis. solids
208
270
160
100
Qds
tons /mo
60
43
370
528
m-Vsec
0.08
0.05
0.32
0.67
Station T5
Dis. solids
mg/i
81
150
120
44
Qds
tons /mo
17
20
101
78
m^/sec
0.18
0.17
1.04
2.33
Station T8
Dis. solids
165
200
190
110
Qds
tons/mo
78
90
519
679
-------
Station T5 is on Bear Creek, the only tributary to the river between
stations T4 and T8. Thus, the difference between the dissolved solids
discharge at T8 and the sum of the discharges at T4 and T5 is the rate
of dissolved solids pickup between T4 and T8. The total dissolved solids
pickup for the four months listed in Table 7 is 149 metric tons.
The source of the dissolved solids accumulated between stations T4 and
T8 is tailings pond no. 6, the only presently active disposal area. The
quality of percolate from tailings pond no. 6 was monitored from three
groundwater sampling stations and form a subsurface drain extending under
the tailings. The average water quality from the groundwater stations
and from the drain are given in Table 8. Also included are the water
quality parameters for the water which is used to transport the solid
tailings, as well as the results from the saturated paste analysis of
sample 6-5. This sample is a composite of 12 samples of tailings at
different depths from four different locations on tailings pond no. 6.
Incident precipitation and tailings transport water percolate into the
interior of the spoil bank and build up a groundwater mound from which
leachate moves toward the boundaries of the pile. This is evident from
the water table map shown in figure 10, which shows the direction of
groundwater flow to be toward Bear Creek on the west and the San Miguel
River on the north. No piezometers were installed on the east end of
talings pond no. 6, but there is undoubtedly a component of flow to the
northeast. A portion of the groundwater which moves northeast probably
enters the river above station T4.
The source of salts in the tailings ponds is, evidently, quite different
from that in the strip mine spoils. The water used to transport the
tailings to the disposal area contains 720 mg/J, of dissolved solids.
Combining this number with the 4.2x10 m of transport water used in
each operational day results in an estimated daily discharge of 3 metric
tons of soluble salts to the disposal area. Over a sufficiently long time
46
-------
Table 8. AVERAGE CHEMICAL CHARACTERISTICS OF
OF WATER AND TAILINGS BETWEEN STATIONS T4 AND T8.
Parameter
Acidity, mg CaC03/A
Alkalinity,mg CaC03/fc
Total hardness, mg/fc
PH
Specific cond.,pmohs/cm
Dissolved solids, mg/A
Aluminum, mg/&
Calcium, mg/Jl
Chloride, mg/£
Copper, rngA
Dissolved iron,mg/Ji,
Potassium, mg/l
Magnesium, mg/£
Manganese,mg/£
Sodium, mg/A
Lead,mg/£
Sulfate,mg/£-
Zinc,mg/£
Groundwater
samples
22
83
576
7.2
1406
1000
<0.5
219
4
<0.1
<0.08
20
7.2
21
29
<0.15
389
-
Drainage
samples
3
52
394
7.6
1276
975
<0.8
238
81
10
<0.05
34
1.4
<0.5
70
<0.15
345
0.17
Transport
samplea
~0
160
310
11
1200
720
1.9
260
>250
20
<0.05
27
0.04
<0.01
53
0.21
180
<0.01
Tailings
-
-
-
7.7
2047
-
-
39
20
-
-
58
15
-
64
-
240
-
Results for one sample only.
period, it is reasonable to assume that storage of these salts in the
pile approaches zero. It is expected, therefore, that the long term
average contribution of dissolved solids to the receiving waters is 3
metric tons per operational day. This conclusion is derived, however,
on the basis that the concentration of dissolved solids of 720 mg/£,
obtained from one sample of transport water, is representative. Contin-
ued monitoring of the quality of the transport water is being accomplish-
ed in order to establish an average value.
47
-------
00
TELLURIDE SITE
6 TAILING POND
£&?SSSM*m*S*&&^^
ISO
100
SCALE : METERS
90 0
ISO
Figure 10. Water table map at Tailings Pond no. 6.
-------
The observed salt pickup between stations T4 and T8 is not as great as
might be expected from the above computation. It has already been indi-
cated that some groundwater movement from the northeast side of tailings
pond no. 6 probably enters the river above station T4 and thus accounts
for part of the discrepancy. Stream depletion by flow from the stream
to the groundwater aquifer is believed to contribute to the discrepancy
as well. The discharge measurements on Bear Creek were made immediately
above the point where Bear Creek enters the alluvium in the valley floor.
This alluvium is composed of sand, coarse gravel, and cobbles. It is
quite possible for significant quantities of water to flow from the
stream into the alluvium on the west side of Bear Creek, while ground-
water from the tailings pond flows into Bear Creek from the east side.
There is also a high probability of water loss from the San Miguel River
to the alluvium between the confluence with Bear Creek and station T8.
These comments are strongly supported by the measured discharges at T4,
T5, and T8 reported in Table 7 which show that the cumulative discharge
over the four months at station T8 is only 89 percent of the sum of the
cumulative discharges at T4 and T5. A loss of 11 percent to the alluvium
is indicated. In addition, groundwater from the tailings pond may be
moving across Bear Creek as underflow and returning as surface water
downstream of station T8.
NAVAJO MINE SITE
A water quality monitoring program was not established at the Navajo
site because of the intermittent nature of the runoff and limitations of
time and budget. Samples of the spoil and overburden were collected,
however, and subjected to saturated paste analyses. The average results
of these characterizations are presented in Table 9. Also included are
the corresponding chemical characteristics of a water sample from a pond
located in the pit near the north end of the mine (figure 6), and of
2
water samples collected and analyzed by Rabinowitz and Billings (1973).
There exists a general correspondence among the chemical characteristics
49
-------
Table 9. AVERAGE CHEMICAL CHARACTERISTICS OF
WATER, SPOIL, AND OVERBURDEN, NAVAJO MINE.
Parameter
pH
Dissolved solids, mg/i
Specific cond. ,ymohs/cm
Calcium, mg/S,
Magnesium,mg/A
Sodium, mg/A
Potassium,mg/£
Bicarbonate, mg/£
Chloride,mg/£
Sulfate,mg/fc
Copper, mg/Jt
Dissolved iron,mg/Jl
Mang anes e , mg / 4
Zinc, rag/ £
Lead, rag/ Z
Aluminum, mg/£
Nitrate,mg/£
Spoils
8.0
-
3960
31
212
622
27
149
30
768
-
-
-
-
-
-
-
Overburden
8.1
-
9390
40
229
1800
36
607
32
1490
-
-
-
-
-
-
-
Pit water
8.7
-
17300
-
19
5000
64
-
1850
-
<0.9
-
-
0.02
<0.1
<0.5
20
Shallow
wellsa
7.7
2609
-
153
31
631
11
347
53
1384
<0.1
0.1
0.4
0.2
<0.1
-
-
Pictured
Cliff
aquifer3
7.8
47000
-
170
73
18700
290
3270
24200
17
<0.1
<0.1
<0.01
-
<0.01
-
-
From Rabinowitz and Billings, 1973.
of the spoils, overburden, pit water and the shallow wells, even though
the magnitude of the various quality parameters vary rather widely.
The significant difference in the magnitude of corresponding ions in
the saturated pastes prepared from the spoils and from the overburden
samples can probably be explained by exposure to leaching action. The
spoil samples were taken directly on the surface and ranged in age from
about one year to four years, while the overburden was sampled from the
high wall. Almost certainly, natural areal variability of overburden
also contributes to the differences observed.
50
-------
Chloride concentrations in the pit water are significantly higher than
in the shallow wells. This observation is explained by the fact that
the chloride ion is highly mobile in porous materials and is readily
leached from the relatively fresh spoils. Most of the chloride in the
materials in which the shallow wells are dug would be expected to be
leached out long ago. The same reasoning applies to the difference noted
in the sodium concentrations, except in this case, sodium is flushed
from exchange sites on the clay particles and replaced by calcium and
magnesium. The above observations and discussion indicate that surface
and subsurface runoff, from spoils with chemical characteristics similar
to those determined from the limited number of samples analyzed, will
contain larger concentrations of soluble salts, principally sodium and
chloride, than runoff from undisturbed ground. Because of the variabil-
ity in spoil and overburden characteristics and the very limited areal
distribution of sampling, the degree to which the above discussion applies
to the entire disturbed area is unknown.
The sodium and chloride concentrations in the Pictured Cliff aquifer
below the Fruitland formation are extremely high. A reasonable explan-
ation of this observation is the gradual concentration of these ions by
percolating water from the Kirtland and Fruitland formations above.
Even extremely small interchanges of water between the Pictured Cliff
and the overlying materials are sufficient to account for the high
concentrations, given the millions of years over which the flow could
take place. In any case, deep percolation that may occur through the
mine spoils and eventually into the Pictured Cliff aquifer cannot signific-
antly degrade the already unuseable water.
51
-------
SECTION VII
GENERAL CHEMICAL AND GEOLOGICAL CONSIDERATIONS
The problem of salinization of land and water resources in the arid and
semi-arid regions of the world is one of long standing; dating back to
the early civilizations in the Tigris and Euphrates Valleys. Salts in
soils-generally originate from the weathering process. In humid climates,
natural precipitation is typically sufficient to leach out the soluble
salts as rapidly as they are formed. This is not true in arid regions,
however. Much of the soil in arid regions has been derived from shales,
sandstones, glacial and wind-borne deposits, and unconsolidated alluvium
of various geologic ages. Shales commonly contain substantial amounts
of soluble salts. Kelley (1951) reports that the soluble salts found
in soils of dry climates can be traced to such secondary formations.
Regardless of the original source of the salts in the parent materials,
the salts usually remain inadequately leached in arid and semi-arid
climates, except possibly in the top few centimeters of the soil profile.
Disruption of saline shales and sandstones exposes fresh surfaces for
leaching, and for a period of time, will influence the quality of surface
and subsurface runoff. There is evidence that the spoils produced by
strip mining throughout Rocky Mountain and Northern Great Plains regions
will contain significant quantities of soluble salts. Hodder and
Sindelar (1972) report saline spoils in the Decker, Montana area.
Sandoval et al. (1973) present saturation extract data on 12 spoil
samples in the Northern Great Plains region which are quite similar to
that reported herein. All of these spoils, including those studied in
this investigation, are produced from Upper Cretaceous and Early Tertiary
overburden materials.
An examination of the water quality data (appendix A) and the saturated
soil paste analyses (appendix C) for the Edna Mine indicates that magnes-
ium and calcium are the primary cations while sulfate and bicarbonate
are the principle anions. The sodium, potassium, chloride and nitrate
52
-------
are of secondary prominence. Correlation analyses of the various anion/
cation combinations possible indicates (figure 11) that the sulfate con-
centrations in both the soil/overburden samples and the water are cor-
related with the total calcium plus magnesium concentrations (in mil-
limole units). Neither sodium nor potassium correlate with the sulfate.
The total millimole amounts of these last two cations do correlate well,
however, with the total millimoles of chloride plus nitrate in the soil
analysis results. The soil bicarbonate levels do not correlate with any
cation/anion combination. These observations imply that gypsum (CaSO.
2H-0) and epsomite (MgSo *7H 0) account for the major portion of the
£ *f ^
sulfate present in the ground water and the stream input. Alkali metal
contributions appear to be primarily due to the presence of lesser
amounts of sodium and potassium chlorides and nitrates (with the nitrates
being more prominent).
This inference is supported by X-ray powder diffraction analysis of salt
deposits accumulated along the banks of Trout Creek. The deposit con-
tained primarily calcium and magnesium sulfate with lesser amounts of
the sodium and potassium analogs. The analyses distinctly show the pre-
dominance of sulfate equilibria in the ground water. The most obvious
implication is that the primary sulfate input is due to dissolution of
gypsum and epsomite present in the overburden. The presence of these
minerals in formations of this type is quite common (Kelley, 1951;
Boyko,13 1966; Richards,14 1954). An alternate source of sulfate may be
the action of sulfur-oxidizing (chemotrophic) bacteria within the soil
matrix to form sulfate. The characterization of such production has
been discussed by Galbraith et al. (1972). While this type of mechan-
ism may be operative, the present authors believe that it is unlikely
to be of prominent significance for the systems studied.
Other equilibrium considerations of importance may involve reactions
between soluble and exchangeable cations. Cation exchange phenomena
often occur in soils. The reaction between calcium saturated soil and
a sodium chloride solution, for example, can be written:
53
-------
10
V
o
o
c/i
*
o
o
111
o
1*0
oo
o
o oo
-------
+ 2NaCl = 2NaX
where X denotes the soil exchange site (e.g. clay). As long as soluble
calcium is available, the reaction will not go to completion, but an
equilibrium will be established between calcium ion and complexed cal-
cium. Such ion exchange sites have an almost universally higher affin-
ity for calcium ion relative to that for sodium ion, i.e., calcium ion
will readily replace sodium or potassium on the ion exchange sites. The
same applies to magnesium. As a result, the addition of gypsum (CaSO.)
to saline soils has been widely recommended as a means of forcing alkali
metals from the exchange sites so they can be flushed from the soil via
adequate subsoil drainage (Richards, 1954). The presence of gypsum and
epsomite in the present systems indicates that this phenomenon could be
operative and could serve as a source of sodium/potassium input to the
ground water and thence the stream. The possible extent of such mechan-
isms depends, of course, on the total cation concentration of the ground
water. The USDA Soil Salinity Lab (Richards, 1954) has pointed out that
the sodium adsorption ratio (SAR) may be employed for discussing the
equilibrium relation between soluble and exchangeable cations. The SAR
may be computed from:
SAR =
2
where ( ) denotes the milliquivalent concentrations of the respective
ions. Another important quantity is the exchangeable-sodium-percentage
(ESP), which indicates the number of total exchange sites in the soil
which contain sodium. The ESP thus serves as a measure of the amount
of sodium which could be "flushed" from the exchange sites under the
proper conditions, for example, through the addition of gypsum or
epsomite.
The SAR values calculated from the saturated paste results for the Edna
spoils produced an average value of 0.5. Such low SAR values are indic-
ative of ESP values of less than 1-2 percent. In essence, there is very
55
-------
little sodium or potassium available in these samples which could be
removed from exchange sites. This implies that; (1) there are very
few cation exchange sites available in the materials; or, (2) the
exchange sites have already been flushed free of sodium or potassium.
The relatively high clay contents of the samples in question indicates
that the latter possibility is most likely. The general prominence of
calcium and magnesium in the soil and ground water samples is also
supportive of this possibility.
The data presented above strongly imply that gypsum and epsomite are
primary sources of calcium, magnesium, and sulfate. Because dolomite
(Ca Mg (CO,) ) and calcite (CaCO ) constitute a large fraction of the
total carbonate rocks, it would not be unreasonable to expect that these
two minerals might serve as contributors to the calcium, magnesium, and
total carbonate concentrations. Hsu (1963) has pointed out that sub-
surface waters tend to have Ca /Mg concentration ratios indicative of
the type of carbonate with which they are in equilibrium. Strum and
Morgan have developed stability relations for Ca -Mg , CO^-H-O sys-
tems which may be used to crudely infer the identity of the carbonate
mineral/water system. The water quality data for Trout Creek generally
shows Ca/Mg ratios of 1.5 to 2.0. Such ratios imply the predominance of
calcite dissolution if carbonates are primary sources of the calcium
and magnesium. The fact that calcium carbonates are generally 3 to 4
orders of magnitude less soluble than the sulfate implies that carbonate
dissolution plays a minimal role. The water quality measurements and
the soil analyses, however, both indicate the existence of carbonate
equilibria. A simple model of aqueous carbonate solutions predicts that
the prominent carbonate species in water with a pH of about 7.7 will be
the bicarbonate ion. This explains the fact that no carbonate ion was
detected in the saturated paste analyses.
The results of the saturated paste analysis (appendix D) for the Navajo
spoils and overburden are significantly different than for the Edna
spoils. In particular, the sodium concentrations exceed the combined
56
-------
concentrations of calcium and magnesium. Correlation analysis of these
results indicates that the sulfate concentration correlates better with
the sodium concentration than with the total calcium plus magnesium con-
centration. This implies that sodium sulfate is the major source of
sulfate in the Navajo spoils, but does not rule out contributions from
calcium and magnesium sulfates. The clay minerals in the Navajo spoils
can be characterized as sodium saturated, as indicated by the sodium
adsorption ratios and the exchangeable sodium percentages listed in
Table 10. Such materials are notorious for their low water-intake
capacity caused by clay particle expansion.
Table 10. SODIUM ADSORPTION RATIOS
AND EXCHANGEABLE SODIUM PERCENTAGES
FOR NAVAJO SAMPLES.
Sample
R-l
R-2
R-3
R-4
R-5
R-6
FBI
FB2
FB3
SAR
12.1
4.7
15.9
14.4
22.7
15.5
36.3
38.9
28.1
ESP
16
5.5
22
20
37
22
50
57
40
The mineral composition of the water in the San Miguel River and its
tributaries would be expected to be quite different from that at the
Edna or Navajo sites because the origins of the minerals are igneous,
intrusive rocks. The overall chemical composition of the water samples
is extremely difficult to explain in detail and will require a great
deal more research before it is adequately understood. It is possible,
however, to take a quantitative approach to the sulfide equilibria that
57
-------
are certainly involved. Using the zinc sulfide mineral, sphalerite, as
a specific example, the dissolution reactions may be represented by
ZnS,,* Zn+2 -t- S"2
-22
The solubility product constant for ZnS is 3x10 suggesting that its
solubility in water and therefore its contribution to the degradation
of water quality would be very low. Actually, the solubilities of metal
sulfides are controlled by acid-base (hydrolysis) reactions involving
the sulfide ion and by reactions involving the conversion of the metal
sulfides to more soluble salts. The hydrolysis of the sulfide ion pro-
duced from the dissolution of metal sulfides is a two-step process des-
cribed by:
s-2 + H Q+
HS" + H30+
S-2 + 2H/
2 HS"
Z H2S
^ H2S
+ H20
.H20
+ 2H20
(a)
(b)
(c)
(c) (overall reaction)
The equilibirum constants of these reactions are given by:
(H 0+) (S=)
(HS~)
K = _ - =1.2x10""
HS~) (H30 ;
(H2S)
- iYin
" XAXvl
K,
and
(S-2)(H30*) IMC,,
(H2S) (HjO)
Therefore: -2 l,2xlO-20
These equations show that the sulfide released during the dissolution
of metal sulfides is essentially all converted to HS~ at pH values
ranging from approximately 8 to 11; if the pH is below approximately 7,
the sulfide is converted largely to H S. The result is the effective
removal of sulfide ion itself from the system, thereby allowing dissolution
58
-------
of more metal sulfide. Using the equilibria constants outlined above,
the calculated solubility of ZnS at pH of 6 is approximately 2 ppm.
This value is below that often observed for the water quality measurements.
Some of this discrepancy is due to the formation of soluble zinc hydrox-
ide and Zn(HS) complexes which effectively increase the solubility of
the metal sulfide. The presence of sulfate in the water may offer a
more logical explanation for the discrepancy. Sulfate ion reacts quite
readily with most metal sulfides to form the corresponding sulfates.
These sulfates are universally more soluble than the sulfides. Galbraith
et al. (1972) have considered this possibility as a likely explanation.
59
-------
SECTION VIII
PROJECTED WATER QUALITY DEGRADATION FROM STRIP MINE SPOILS
The discussion thus far has centered around the nature and magnitude of
water quality degradation observed at the study sites over a nine month
period. The data presented are not indicative of the average situation,
however; nor do they provide direct information on the total quantities
of salt that will eventually be produced nor the time period over which
the salt pickup will remain above ambient levels. The most efficient
and reliable method of obtaining answers to the above questions is
through the use of a well verified mathematical model. Such a model is
not available at this time, and therefore, the estimates presented in
this section are derived by methods requiring more assumptions, judgment,
and speculation than is desirable. The authors believe, however, that
it is important to establish "order of magnitude" values for average
salt pickup rates and total salt pickup so that the problem of salt
production from strip mine spoils can be more accurately judged in
relation to national priorities and future research needs. The authors
regard the numerical quantities reported in this section as indicators
of magnitude and attach a limited significance to the actual numbers.
TOTAL LEACHABLE SALTS
Estimates of the total quantities of soluble salts were derived from the
leaching experiments described earlier in this report. The results of
the leaching experiments are summarized in figures 12 and 13. The
relationshops shown in these figures were prepared from the data tabu-
lated in appendix F. The specific conductance of each increment of
leachate has been normalized by dividing by the conductance of the
saturated paste extract corresponding to each column. These values
were then plotted as a function of the cumulative leachate volume
expressed as a ratio to the bulk volume of sample. This method of
handling the data caused the results from the three Navajo columns to
60
-------
O
u
O
lil
QC
i
>-
H
O
S
i
0-02
2 4 6 8 10 12
CUMULATIVE LEACHATE VOLUME/ BULK SAMPLE VOLUME
Figure 12. Normalized leaching data from three
samples of overburden - Navajo Mine.
-------
0-03
2468
CUMULATIVE LEACHATE VOLUME / BULK SAMPLE
10
VOLUME
12
Figure 13. Normalized leaching data from six
samples of spoils and overburden - Edna Mine.
-------
define a single relationship fairly well as shown in figure 12. The
same procedure was used to obtain the curve shown in figure 13 for the
six Edna columns. Before normalizing the data in the above manner, each
test defined a distinct and individual relationship.
Assuming that the soluble salt concentration is proportional to the
specific conductance, the area under the curves in figures 12 and 13
in any increment of leachate volume is proportional to the quantity of
salts removed in that increment. The total quantity of soluble salts
per unit volume of spoil can be determined by this procedure, only if
an effectively infinite volume of leachate is collected. Therefore,
it is arbitrarily assumed that removal of salt is negligible after the
conductivity of the leachate has decreased to 5 percent of the saturated
paste conductivity. It is noted from figures 12 and 13 that this criter-
ion requires a total throughput of water equal to 10.1 times the volume
of the Navajo samples and 6.8 times the volume of the Edna samples. The
average saturated paste conductivities for the Edna samples and for the
Navajo spoils are 3110 and 9390 micro-mohs/cm, respectively. Using the
14
Handbook 60 (1954) correlation between specific conductance and total
dissolved solids, the corresponding dissolved salts concentrations are
2200 ppm and 7300 ppm. Using these concentrations and integrating the
funetions in figures 12 and 13 to the cumulative leachate volumes cor-
responding to a 95 percent reduction in specific conductance, results
in estimated removable salt contents of 2.4 kg/m for the Edna spoils
3
and 23 kg/m for the Navajo overburden.
The numbers computed above imply that 2.4 kg of salts must be removed
from each cubic meter of Edna spoil and 23 kg from each cubic meter of
Navajo material before the concentration of salts in the throughput
water is reduced to a negligible level. Strictly speaking, these
quantities apply precisely only to the samples subjected to leaching.
Very significant variations in salt content with location can be
expected, especially at the Navajo Mine. Literally hundreds of such
tests might be required to establish a statistically significant
63
-------
distribution of salt contents. This procedure was beyond the scope of
this work. Weathering and microbial activity over long time periods are
very likely to cause the total quantity of soluble salts to be even
higher than calculated from the leaching experiments. The weathering
rate of some shales and siltstones exposed on the spoil surface was
observed to be very rapid. Apparently competent shale fragments were
observed to crumble and disseminate in a matter of a few weeks upon
exposure at the surface. Traces of salt deposits formed by evaporation
from the shale surfaces were evident upon close examination. In addition,
no statistically significant increase of soluble-salt content with depth
of sampling was observed in the Edna spoils. These observations indicate
that continual exposure of fresh surfaces by weathering processes will
tend to make the total quantity of salts eventually removed to be higher
than that observed in the leaching experiments.
AVERAGE ANNUAL SALT PICKUP
The salt pickup rate and, therefore, the time required for salt removal,
depend heavily upon the quantity of surface and subsurface runoff from
the spoils. The average annual surface and subsurface runoff are dif-
ficult to estimate, however. Approximately one-half of the annual pre-
cipitation of 51 cm (20 in) that falls at the Edna site is in the form
of snow. Thus, the quantity of water that becomes available for infil-
tration, runoff, or evaporation during the spring months of April and
May is much larger than the quantity of precipitation during these months
and the infiltration capacity is exceeded. Surface runoff from the spoils
is quite small at all other times of the year, however.
Based on an estimated mean annual discharge of 2.84x10 m (2.3x10 acre-
feet) for Trout Creek at the downstream limit of the Edna Mine and a
4
watershed area of 1.1x10 ha(43 square miles), the average annual surface
and subsurface runoff is 26 cm (10 in). The large fraction of the water-
shed is at higher elevations and receives more precipitation than the
Edna study area, however. This fact indicates that the surface and
64
-------
subsurface runoff from the spoils would probably be less than 26 cm.
On the other hand, most of the watershed is very well vegetated which
would tend to increase evapotranspiration relative to the less vegetated
spoils. In the absence of a better estimate, 26 cm of surface and sub-
surface runoff is assumed to apply to the Edna spoil area. The normal-
ized salt pickup rate of 0.21 metric tons per hectare per centimeter of
runoff, derived in a previous section of this report, and the above
figure of 26 cm results in an estimated average annual salt pickup rate
of 5.5 metric tons per hectare per year (2.4 tons/acre/year). Surface
and subsurface runoff and precipitation measurements at the Edna site
will continue through June, 1976, in an attempt to refine and establish
a reliable average annual salt pickup.
It is interesting and important to calculate the normalized annual salt
pickup rate from the results of the saturated paste analyses. The
average saturated paste conductivity for the Edna spoils is 3110 micro-
mohs/cm which corresponds to a dissolved solids concentration of 2200 ppm
14
(USDA, 1954). Assuming that the dissolved solids concentration in
surface and subsurface runoff is also 2200 ppm, the calculated normalized
salt pickup rate is 0.22 metric tons per hectare per centimeter of sur-
face and subsurface runoff, which agrees quite closely with the measured
value of 0.21. The agreement is important because it implies that total
salt pickup can be estimated from the relatively simple saturated spoil
analysis and a knoivledge of the hydrology; thus, providing a method of
judging one of the impacts of strip mining before ground is broken.
A normalized salt pickup rate for the Navajo spoils was not measured,
and therefore, is calculated from the specific conductance of the over-
burden sample analyses. The only justification for this approach is
the observed agreement between the measured and calculated values of
normalized salt pickup rate at the Edna Mine. The average specific
conductance is 9390 micro-mohs/cm which corresponds to a concentration
of 7500 ppm; a value considerably lower than that observed in a drainage
pond in the pit (see Table 9). The normalized salt pickup rate is 0.73
65
-------
metric tons per hectare per centimeter of surface and subsurface runoff
(0.79 tons/acre/in).
The average annual surface and subsurface runoff from the Navajo spoils
is difficult to determine with accuracy. The spoils are regraded so as
to preclude surface runoff in significant quantities beyond the boundaries
of the disturbed area. Many small closed basins are formed, in which,
all incident precipitation evaporates and percolates into the subsurface.
The problem is to estimate the quantity which eventually results in deep
percolation. Actual measurement of the quantity of deep percolation
from a statistically significant number of the small basins over a time
period sufficient to establish an average value would constitute an
expensive and time consuming project. Therefore, an indirect estimate
was made. Although the accuracy of the following estimate of subsurface
runoff (deep percolation) is certainly open to question, the resulting
salt pickup rate is so low that a concerted effort to refine it by dir-
ect measurement seems unwarranted. This is especially true since the
possibility of the estimated deep percolation being grossly lower than
the actual value is quite remote, and since the pre-existing groundwater
is highly mineralized.
An estimate of the quantity of subsurface runoff was based on laboratory
and field measurements of evaporation from bare soil by Gardner '
19
(1973,1974). Gardner found that 69 percent of the total quantity of
water applied to three columns of a loamy sandy soil, in a variety of
time and quantity distributions, was evaporated under conditions in
which the ability of the soil to transmit water to the evaporating sur-
face was limiting. In field experiments with a fallow silty loam soil
20
over a four year period, Gardner's data shows that an average of 70
percent of the incident precipitation was evaporated. The low was 65
percent and the high was 74 percent. The quantities of precipitation
were not reported in the above referenced papers, but were obtained by
personal communication. The measurements were conducted in eastern
Colorado during the summer growing season when the potential evaporation
66
-------
was not limiting.
The spoil materials at the Navajo Mine weather to produce soils with a
variety of textural classifications. Many of them are heavier soils than
a silty loam, however, and the percent of infiltrated water that eventually
evaporates is likely to be larger in the heavier soil. Thus, the percent
of infiltrated water which eventually evaporates from the Navajo spoil
was arbitrarily taken as 90 percent. This results in an estimated annual
deep percolation of 1.7 cm which was rounded to a value of 2 cm. The
annual salt pickup rate is estimated to be 1.4 metric tons per hectare
(0.6 tons/acre). The net salt pickup caused by mining is even lower
because the dissolved solids concentration in surface and subsurface
runoff from undisturbed ground may be 2500 ppm or more (Rabinowitz and
Billings,2 1973).
67
-------
SECTION IX
REFERENCES
1. Fassett, J. E. and J. S. Hinds. 1971. Geology and Fuel Resources of
the Fruitland Formation and Kirtland Shale of the San Juan Basin,
New Mexico and Colorado. U. S. Geological Survey Professional Paper
676.
2. Rabinowitz, D. D. and G. K. Billings. 1973. Estimate of Surface Water
and Effect on Mining. Private Report, Utah International, Inc..
3. Bass, N. W. , J. B. Eby, and M. R. Campbell. 1955. Geology and Mineral
Fuels of Parts of Routt and Moffat Counties, Colorado. U. S. Geological
Survey Bulletin 1027D.
4. Campbell, M. R.. 1923. The Twenty-Mile Park District of the Yampa
Coal Field, Routt County, Colorado. U. S. Geological Survey Bulletin
748.
5. Tweto, 0. and P. K. Sims. 1963. Precambrian Ancestry of the Colorado
Mineral Belt. Geological Society of America Bulletin V. 74.
6. U. S. Department of Interior. 1970. Environmental Protection Agency
Methods for Chemical Analysis of Water and Wastes.
7. Hergert, G. W. 1971a. Methods for Soil Characterization. CSU Soil
Testing Laboratory, Colorado State University, Fort Collins, Colorado.
8. Hergert, G. W. 1971b. Soil Testing Methods. CSU Soil Testing Labora-
tory, Colorado State University, Fort Collins, Colorado.
9. Skogerboe, G. V. and W. R. Walker. 1972. Evaluation of Canal Lining
for Salinity Control in Grand Valley. Report 13030 DOA/1-72. U. S.
Environmental Protection Agency, Washington, D. C. .
10. Kelley, W. D. 1951. Alkali Soils. Reinhold Publishing Corp., New York.
11. Hodder, R. L. and B. W. Sindelar. 1972. Coal Mine Land Reclamation
Research. Montana Agricultural Experiment Station Research Report
No. 21.
12. Sandoval, F. M., J. J. Bond, J. F. Power, and W. 0. Willis. 1973.
Lignite Mine Spoils in the Northern Great Plains - Characteristics
and Potential for Reclamation. Research and Applied Technology Sym-
posium on Mined-Land Reclamation, Pittsburg, Pa.
68
-------
13. Boyko, H. 1966. Salinity and Aridity, Dr. W. Junk Publications, The
Hague.
14. Richards, L. A. 1954. Diagnosis and Improvement of Saline and Alkali
Soils. U. S. Department of Agriculture, Handbook No. 60.
15. Galbraith, J, H., R. E. Williams, and P. L. Siems. 1972. Migration
and Leaching of Metals from Old Mine Tailings Deposits. Groundwater,
Vol. 10, No. 3.
16. Hsu, K. J. 1963. Correspondance with Editor. Journal of Hydrology,
Vol. 1.
17. Strumm, W. and J. Morgan. 1971. Aquatic Chemistry. Wiley Interscience,
New York.
18. Sindelar, B. W., R. L. Hodder, and M. E. Majerus. 1973. Surface Mined
Land Reclamation Research in Montana. Montana Agricultural Experiment
Station, Research Report No. 40.
19. Gardner, H. R. 1973. Prediction of Evaporation from Homogeneous
Soil Based on the Flow Equation. Soil Sci. Society of Amer. Proc.,
Vol. 37.
20. Gardner, H. R. 1974. Prediction of Water Loss from a Fallow Field
Soil Based on Soil Water Flow Theory. Soil Sci. Society of Amer.
Proc., Vol. 38, No. 3.
69
-------
APPENDIX A
WATER QUALITY DATA - EDNA MINE SITE
Table A-l. DESCRIPTION OF WATER SAMPLE LOCATIONS AT EDNA MINE SITE.
Sample
designation
Description*
Cl
C2
C3
C4
Surface water sample from Trout Creek above all active
mining on the water shed.
Surface water sample from Trout Creek immediately above
the Edna Mine.
Water sample from surface and subsurface drainage tribu-
tary to Trout Creek near the southwest limit of spoil area.
Surface water sample from Trout Creek below the south
mined area and immediately above the active north mined
area.
Water sample from surface and subsurface drainage tribu-
tary to Trout Creek between the south and north mined area.
Surface water sample from Trout Creek near the downstream
limit of mining and immediately above irrigation diversion.
Groundwater sample from seepage face immediately below
the north mined area.
Surface sample from Trout Creek at the downstream limit
of mining activity.
Groundwater sample from observation well near station C4.
Direct surface runoff from a spoil bank in the south mined
area.
figure 4 in text.
C5
C6
C7
C8
CP1
May Runoff
70
-------
Table A-2. h'ATUR ANALYSIS DATA TOR OCTORf.R 1973.
«4
< X* "V
"^ u ^. 5fl
. 0 .- *1 ./I £
XO = O in
U - U 3 tr .
_ .*»"*>£*
% Temp 2 J JJ " "22
a °r -j =t a n a .
in v < e <. e u
Cl 5.0 85 06
C2 5.5 96 96
C3 10.0 110 1930
C4 11.7 100 120
CS 13.5 180 2590
C6 12.5 110 160
C7 6,5 >200 1450
C3 7,2 170 200
CP1
-3
O
>
M
« 3« o -3 "3
J1S £. 4 P! -< fl -(
CCO1^" w *-^.
nit O6 3 O 2O O =4
1 uj « H « H a
T.2 61 50 19 b'J
7.1 65 2.4 57 59
7.4 24SO 1.3 2-JS2 M83
7.7 273 2.4 132 134
7.7 3480 6.8 3467 3474
7.8 270 2.6 82 85
7.2 3680 34 3414 344R
7.5 277 3.9 192 196
Al Ca Cl Cu
mg/t mg/l ng/l mg/t
<0.1 24 <1 <0.1
<0.1 23 <1 <0.l
<0. 1 320 6 <0.1
<0.1 39 <1 <0.1
<0.1 290 S <0. 1
<0.1 38 1 <0.1
<0.1 210 8 <0.t
<0.1 38 1 <0.1
Fe Fe Fe
ills. unJis. total K Mg
nj/t mg/l ng/t mg/i rag/t
<0.03 0.2H 0,29 <1 7-6
0.13 0.16 O.:n 1000
C8 5.0 100 150
CP1 - 300 290
-3
> «
- w . of m
«! ^- 3 *» -3
U OA 'yi io -,
C "3 E r. B
u n '> -< o
.- u ~3 -3 * in
u. u e in *
-. ~ '-" t> "3 * "^ ^^
J-3.C i. ' fl rj ««
OCO'n ~ « w-v
oil OS 3 O 0 O O =4
« ' e/i o s v/i w =- '/i t- E
".S 161 - 160
7.6 164 1.4 ll>0 160
3. i 25SO 9.2 ::>oo 2310
7.7 222 - 210 -
7. T 3080 - .3180
7.1 270 .73 220 220
6.0 3S50 27 3400 3430
7.7 278 1.4 185 190
7.4 3680 - 2200 -
Al d Cl Cu
mg/l mg/l mg/t ng/f
<0.1 31 <1 <0.1
<0.1 31 <1 <0.1
<0. 1 360 4.8 <0.1
400 0.0!
400 0.015
400 13
-------
Table A-4. WATER ANALYSIS DATA TOR niiCP.MBLR Ij
is)
* «J
« x-« >>
>. «j -v. a
. n) .- M in g
xo e p m
O w '_) i O O
e. Temp 2 "3 j» <3 | a
:j »r uu->wno
/i u < « < a = w
C1 0.0 0 110 100
c: o.o 6 no too
C3 1.0 6 110 1800
C4 1.2 0 100 160
CS 1.2 0 160 2300
C6 0.5 6 58 140
C7 4.2 '6 330 1600
C3 0.0 6 44 ISO
CP1 - IS 270 1800
|
W ** t/l
O *» O ->v -3
0 ' « «.«-<
C -3 a n H
O rj «> -< O
.. w -3 -3 «
u. u e (ft <«
« 3 '/I O O T "
war o.-- n .-. n *j
t> C D W. *l ~ W's,
pll i.as a o o o o u
r" to un l/» in H in 1- e
7.7 183 -0 100 100
7.6 137 -0 120 120
7.4 2510 -0 2300 2300
7.4 305 '0 160 160
7.4 3160 "0 3200 3200
7.2 355 '0 170 170
7.5 4700 5.1 3400 34! 0
7.2 285 '0 200 * 200
7.4 3610 680 2660 3440
Al Ca Cl Cu
i*K/' i»i/l as/ 1 »6/t
460 0.094
0.019 4.7 >800 0.03i
<0.010 S.9 <0.16 50 0.008
<0.010 1099 0.20 >450 0.019
<0.010 7.3 <0.16 59 0.014
1.3 22 <6.16 >400 3'J
Table A-S. KATI:H ANALYSIS DATA FOR JANUARY 1974.
«l
" >, » ~»
s. *J x. M
. -» rt M 5
o ?8 .53 3^.
§ ~fp i3 2* 13
n Jc -j « « 13 a
'A
* M " ml 'A
'> -^ O »x -3
U DO V. Zti '
C "3 fi me
^ n c/ i 3
- w T5 » "5 tf»
' u - <^ -f.
.--.-. ^ -3 ^ _
'w ^^ » -^ r: -3 **
'* ~ ~ -J. ~* ** -* ^ ^
nil :-ss is a a o -.1
y;u_it/>« r-«r-e
7.7 is3 -o no no
7.8 187 2.J 110 110
7.9 2310 4.7 2JOO 2300
S.O :53 3.7 170 170
7.7 2nOO "0 2SOO 2800
8.1 2SO 6.0 190 200
7.9 4340 23 3700 3720
8.1 310 -0 210 210
Al Ca Cl Cu
m;j'» r-£ll ""R/1 "S/1-
100 «0.01
<0.05 46 800 0.044
0.022 4.0 <0.14 100 <0.01
<0.01 95 <0.14 >800 0.019
0.026 4.6 <0.14 100 <0.01
<0.01 1050 <0.14 >800 <0.01
O.C24 6.0 <0.14 110 0.024
-------
Tuble A-6. KATER ANALYSIS DATA FOR>FEBHUARY 1974.
*4
'>%' -X
"X. ** >^ SO
KI .^4 w v) a
xo so KI
v *> u .-. u u .
§ rwip ? 3 % & 72
5 rr v w a r: o
« < e < I* = u
Cl 1.1 0 100 111)
C2 1.0 0 100 110
C3 l.S 0 120 1SOO
C4 0.0 0 120 190
r.:-, o.o o 73 >iooo
C6 0.0 0 100 210
C7 3.S 188 350 1500
C8 0.5 0 120 250
CP1
|
-i - in
800 0.042
0.04 5.6 <0.1 91 <0.02
0.015 83 <0.1 >800 <0.02
0.04 7.5 <0.1 92 800 0.015
O.OS 8.6 <0.1 96 <0.02
CM
Table A-7. KATIiR XXALYSTS DATA TOR M\HCII 19T4.
« B<
»* x * >,
^ *J *^. St.
. If. .-1 tf. -A g
^O CO "i
4) . « y -j i .
TO-IP "*^ iJ fl u - n
a '*- " J< »« w
-! °f 'J M « r. 3
V! * < B < E «
Cl 0.5 :! 110 1^0
C2 0.5 <1 120 120
C3 0.5 <1 66 1500
C4 0.5 <1 i:0 280
CS 2.0 5.5 ICO 1300
C6 0.5 <1 100 340
C7 3-0 <1 330 2000
CS 0.5 <1 110 360
CP1 - <1 240 2000
3
>
w mi in
J --» O -x -3
J x in :.:
= -3 S « £
j n -s o
- - *^ "^ -^ » /!
**. y " '/) vi
>=/! j -3 -J
^ "TJT C ' n -» rt «J
li i 3 V: » w *-->.
nil 3=30 O O CU
r^" X -j 3. 'f, in r- vi r- s
7.9 245 2.6 150 ISO
7.9 240 -Q 11!) 110
7.4 2 no i.s :ooo :ooo
7.7 525 -0 370 370
7.j 2850 2.7 276v) 2'GO
6.9 700 4.2 4SO 480
7,3 4250 3.4 3640 3640
7.7 630 3.0 460 460
7.5 3000 67 2520 2590
Al Ca Cl Cu
^S/«- ^S/J ras/1 m£fi
'O.S SI 1 <0.1
'0.5 51 <1 <0.1
0.5 450 5 <0.1
-0.5 97 1 <0.1
803 0.071
0.03 7.0 <0.1 230 0.017
<0,02 74 800 0.012
0.04 11 -.0.1 20S <0.01
<0.02 500 <0.1 >800 <0.01
0.06 13 <0.1 270 <0.01
O.SS 19 <0.1 >800 17
-------
Table A-8. HATER ANALYSIS DATA FOR APRIL 1974.
» x»» ^
.-fcs^i.sr
£8 .58 S .
1 reap 2*3 ««3 |3
3 °c i! Sf 3 ? 2 2
ct - <1 120 460
C7 S.O U 210 1850
CS 4.S <1 120 470
CP1 - <1 100 18PO
|
» M < n
O "^, O v. &
u u X u -
C -3 B Kl B «
UB « 0
-» u -O - -3 «
W U C tft M
" aw o rs ^ *
u-ac n < a «r
oeowi-^ w-4 *-»*<»,
PH *65 Ji 2 S 2 £ if
8.2 190 '0 130 130
8.0 200 -0 120 120
7.3 1890 -0 19SO 1950
8.1 853 9.8 690 700
8.0 2600 43 2530 2S9U
7.8 785 10 590 6CO
7.7 2620 -0 2520 2520
7.8 894 6.2 6CO 670
7.7 i970 4S 1730 3780
Al Ca Cl Cu
mg/i mj/l mg/t ng/t
-------
Table A-9. hATI'R ANALYSIS DATA POIl M\Y l'J74.
ol
» x»< -x
*H. M -V. 30
,*..- *> IT. S
XO e O >
Cl M (_' U O
g iCSll ._ jj ^ ,_,
n °r u M > eo n o
*
«i «4 w tn
O >. o -3
u
-------
Table A-10. h'ATIiR ANALYSIS DATA FOR ,IUNC 1974,
O".
*
1 X«» -»
S, « V. M
. M .- HI MB
u J?8 58 S .
-« «*«*««{;»«
g- T«np 30 jJ«J f 3
a "c < < ? a s
Cl 16 »
*« -* W tfl
W >. O >«. t)
U M vi C4 -
c T) a « B
Ort 5 -.0
4 4J *O «W to
<*
*«3wi5TJ ^y «
u-is: s.-i n -> a *
nt| S.5e So p o o M
' v> ua vt *> K* u> t- a
7.7 147 - 110
7.8 147 - 110
7.7 2400 - 2100
7.5 201 - ISO
7.3 3100 - 2800
7,9 286 - 180
7,5 5200 - 4400
7.7 303 - 190
7.2 2400 - 2100
Al Ca Cl Cu
mu/t rag/t ng/l "K/t
<0,5 - <1 «0.09
<0.5 - <1 <0.09
<0.5 - 3,2 <0.09
-------
APPENDIX B
WATER QUALITY DATA - IDARADO MINE SITE
Table 6-1. DESCRIPTION OF WATER SAMPLE LOCATIONS AT IDARADO MINE SITE.
Sample
designation ^ Description
Tl Surface water sample above tailings and immediately below
the confluence of Bridal Veil and Ingram Creeks.
T2 Mine drainage discharge.
T3 Surface water sample from Marshall Creek; contains some
mine discharge.
T4 Surface water sample from San Miguel River immediately
above active tailings pond No. 6.
T5 Surface water sample from Bear Creek at entry onto valley
floor and upstream of tailings pond No. 6.
T6 Subsurface drainage sample from pipe extending beneath
tailings pond No. 6.
T7 Groundwater seep sample below tailings pond No. 6.
T8 Surface water sample from San Miguel River below the con-
fluence of Bear Creek.
X9 Surface water sample from San Miguel River at confluence
of Prospect Creek.
T10 Surface water sample from San Miguel River at confluence
of the South Fork of the San Miguel several kilometers
below Telluride.
Til Surface water sample from San Miguel River near Placerville,
Colorado.
TP2,TP3,TP8 Groundwater samples from observation wells in vicinity of
- tailings pond No. 6.
TRP Sample from tailings transport system at point of discharge.
aSee figure 4 in text.
77
-------
Table B-2. WATER ANALYSIS DATA FOR OCTOBUK 1973.
00
V
* V *
-V ***. ~^
.-T '* JT- '* 3
X p s £ vi
tt ** C .-_;&
1 Tenp 3 ° 5 5 ! 2
3 °c JJ if S V 5 3
Tl I. IS Jl 1|
Ti J.O 14 190
N b.Q 26 1S»)
la 5.0 71 %
T6 5.1> 41 i;n
T.' i.f. Sij ij->
H 3.4 49 t'.n
T9 4,6 78 19'i
TIO 4.6 83 2iW
ria - 03 i"i
rn
;rs
1
*!* -n
V -^ C * "3
u * ' :; <
C "3 E '^ t3 M
J B 6 - 0
.- i- -j - -3 «
'* 'J S '/I VI
S rt V -3 ~3
JTJ; i..- n - n <
OSO *-* »J * *J*^
.. C.3U3O 03 v a
;M1 v> u a vi m H f t- a
e.o ro s.j ! ;io
6.1 SOO 12 !!><> 208
7.9 l«Si O.SS 4(1 SI
6. ft 1110 5« 342 600
ij . i 39 1 92 :!)2 3S-I
7.0 :»3 0.:: l':5 165
7.1 Ji)8 J.U 117 IJO
7.0 304 1.5 U: 14 1
'.2 . Ji9 1.1 173 171
Al Ca Cl Cu
ms/l ng.'t mj/t ȣ/"
- »"S/t ag/t
"0.05 - <1 1.2
:" 2.4 I
-------
Table B-J. K,VTI:R ANALYSIS :>AVA FOR XOU.MHI.R 1973.
<£>
«J
rJ lK«« ^
-v *- ^*
«-. .*. p* /, ij
£3 5« 3 -
j; f1 _-: _S
1" Ter.:> - " .* "* - i.
r _ ' ., v M - ;
C -5 a « s = "
TI 0.2 3 290
T2 U.J 17 360
13 1.0 2.5 130
TJ 4.7 1J IfrO
T5 3.n 0 9S
T6 5.8 0 MOO
T7 6.2 1.2 1S(>
: TS :.9 J6 13')
T9 2.0 82 160
T10 2.3 -13 250
m 2.4 s: 200
IPS
TP9 ' 71 290
3
5
> «
«*«!* M
W "v. 0 -s. T3
U W Lfl M «-
C T S ' B
y n s> - o-
- w -a - T - j/i
'» -j c r in
Z ifl *J -3 -* "3
O "S £-- " -* fl *
'^ r 5 /- b. -* *- -^
., L_-sa=i oo a --*
i'il --f. -^ -i wj /) : irt - S
t. 1 533 4.0 390 390
'i.4 _*9l> 170 580 750
5.8 :~0 6.6 200 '210
t,.4 2D9 "0 270 2"0
3.4 3t>J 3.2 ISO ISO
:.S 1300 <1.2 940 9-tO
(».h 40? 0.^3 250 2T.O
5.h ^8J 2.9 200 200
9. ft 300 4.4 120 120
6.6 420 1,6 300 300
6.8 310 5.2 220 220
7.0 575 430
Al Ca Cl Cu
*2/l rt£/i r.j/C nj/t
<0.1 100 400 0.015
0.75 4.4 <0,1 120 1.3
0.30 3.6 ;:
\
S.3 20 <0.i 250 b.O
-------
Table B-l. *ATER ANALYSIS DATA TOR DECEMBER l-»73.
00
o
< £ " *-
>:="!£ S S"
> u U -. U 0 -
-^ fl - .1 e ~»
C. T -3 U r] U -3 ;-.
B Tc-p u «. u
3 n- -j wr « n 3
« . C < B < K = -
Tl O.I 17 41 S7t>
TJ 13 20 0.0 170
T3 0.7 in 2.0 310
T4 0.6 7 38 260
T5 0.0 6 64 HO
T6 5.3 17 35 SfoU
T7 t).0 6 40 22H
TS $.} 10 0.0 150
T9 2.7 fi 38 190
T10 1.76 10 230
111 0.6 6 59 210
TPJ
TP3 - 6 35 270
3
* «V *.' v^
tj -v. o ^*s. "a
y ic '/i ^c -*
c -3 e /i e
o n ^ - o
.- _ -3 . -3 . ,n
t*« 'J C W ^
- 3 irt 0 TJ -" -3
M"3 J= C.-- fl - fl W
V = O I/'-' « ~* *-»*^.
PM ^35 5 8 43 2S1
6.3 870 - 840
3.0 91S 630 410 1040
4.i S5" 38 450 490
6.6 J20 - 370
6.7 530 - 140
6.4 915 - 730
6.4 300 310
3.2 333 - 240
6.1 555 '0 240 240
4.2 US -0 330 350
6. I 2i: - 290
7.3 545 .ilO 340 630
At Ca Cl Cu
mv;/t. nf/t op/I mg/t
-------
Table B-S. KATT.R ANALYSIS DATA I'OR JANUARY 1374.
00
w x ** *-
»» - -*- %
- « ^". /: *
>. C s O -/;
u *- ^ *j ^j
H _ -^ u -i * J -2 "~
S Tt-r.p - .* U -
2 >c 2 B < £ 5 2
Tl 0.5 0.0 34 71
T: 12 3.0 so iso
T3 3.0 4.5 IS 150
T4 2.5 J.O 1=; HO
1 T3 0,0 1.0 73 120
T6 4.5 0.0 42 4iO
17 -0 2.0 23 180
' T3 30 i.O 10 140
T9 4.0 0.0 76 160
TlO "0 0.0 55 360
Til -0 0.0 69 230
m ,
i TP8
1
>
j -. ~ ^- '~
j u r. M -
i -i. S » B -
^ i -- 1
... -7 . -g - *
'-*- -J = T. f.
- Z /) - "3 "3 --
j TJ :- '- n -^ r:
V s o '.' *- »- **.
S-3B3O 03 ,9M
[ill I/; -J i V; wi 1-
-------
Table B-6. KATTR ANALYSIS DATA FOR rEBRUARV 1<)74.
00
N>
* **
** », W «V
.>, Z > B If
o fr8 53 S .
S- T«V 2° r-3 f 2
a 'c 3 if < if 5 S
- - - - -
T'
T: S.O 9 S6 400
TJ 0.5 9 55 ZSf)
T4 0.0 4 42 19(1
T3 0.0 S 81 121
T6 4.2 0 i:0 3«0
T7
T8 2.0 4 57 IV,
T9 O.S t 86 17t
T10 O.S 0 SS ISC
Til O.S 0 49 23f
TP3
TP8
2
«--<-'
S -fe ?& 2
vS ? S^ 3
^=5 ?.- »» «
~ a « 5 a TJ
ni «= 2- si
Pii *3 1 3 S 5 S j2 g
7.6 7RO 16 fijn 650
7.5 S35 U 400 400
8.S 390 2.1 290 290
7.7 230 z.e> no no
11.1 1170 21 780 8i)0
7.6 309 190
7.6 J59 1.8 240 240
7.4 363 2.: ?50 250
7.2 490 '0 JIO 310
'
Al Ca Cl Cu
R£/t ng/i *£/£ B£/*
O.S 170 «1 <0.1
<0.5 93 <1 2SO 12
<0.5 67 «1 «0.1
<0.5 69 l.S '0.1
S04 Zn
"R/I Ki/* "S/( °il/1 "S/1
i
0.30 IS <0.1 320 S.4
1.6 8.1 <0,l 300 2.S ]
0.32 S.2 <0.1 120 0.66
<0.02 1.9 <0,l SO
-------
h-7. K,\TI:R ANALYSIS DATA roa MARCH 1971
oo
*f
w x«J *^
>» fc- -^ tf
-* -. r-» 7t g
>. C S C v;
| .Ten? i* 31J f 2
1/5 'C £ S < 9 = ~
Tl
T: 14 1.0 51 450
T3 3.0 3.0 19 160
T4 1.5 4.0 IS 190
; T5 2.0
TP3 - 3 69 890
rrs
~s
J
"J -W 'rt
a »> c ». -a
'J U '/^ 51 '-
e -3 e /. e
- n i 'J
u -3 -3 . /.
' -J S / vi
S 'n y -3 -3
'f~2 n n "
iiaa'o "^ 3=i
pl( (/J-Jicnsrt f-w r-C
7.3 760 160 600 760
6.S 335 0.26 220 220
6.9 390 O.S6 :70 270
7.0 31S 0.64 120 120
9.6 1170 2.S 790 790
7.5 270 0.69 170 170
7.7 343 1.9 230 230
7.4 700 2.0 490 490
8.0 475 1.9 TOO 320
7.1 2000 - 1650
Al Ca Cl Cu
aj.fl nj/i ng/i mg/i
-------
T«ble B-8. KAll'iR ANALYSIS DATA TOtt APISH 1074.
00
*J
» X"< -x
*H w <, £
. fi .. Pi in ff
>.p c o *.
9 * O " 'J O -
a. _._ 3 <3 "5-3 -f ~
Ten? .M t- «<
* ' 7 a Sf < S' 3 £
Tt
TJ IS 50 43 3SO
rs 2.5 i so 230
TJ 3.0 2 36 230
z
M.**J m
s >, s-a a
ug ^D ^# o
cs 1-,- "« "
'Svi V-3 -«-3
JTJ: CL n .- « w
«eo « * '- *>**
pit *8 5 A 2 ,28 ,2 Sf
7.4 749 M 610
7.3 420 11 390
7.7 468 370
TS 5.0 «l 79 ljnjr.8 192 1*0
T8 6.0 2 56 -IhOir.r 1100 6.4 930
T7 J,0 2 45 ;60| 7. 7 4J7 -fl 340
TS J.S 0.14
tO.Ol 2.3 <0.14 32 0.041
3.3 62 <0.14 170 ' a.42
O.U 6.0 <0.14 iSn 1.3
0.02C 5.0 <0,14 97 0.3!)
O.ti! 7.5 <0.14 5i ').2:
0.11 ' 2. a 'C.U "2 0.042
0.046 4.S t'J.U Cl O.OSu
55 35 <0.14 - '.7
2.4 2* <0.14 260 1?
-------
Table B-9. WATl-R ,V..\t.VSIS DATA 1:OU MAY .974.
oo
" X * -*~
~, VJ ^ -..
xg"' '=9 v *
I/ fr* W 'J "rf -
1. ':' < e < " 5 5
Tl 0.0 M N 40
1 T2 li '1 40 360
73 1.3 2 6.4 I'D
T4 1.5 1 24 89
. T3 2.0 <1 83 99
T6 5.0 1 56 t>2
T7 5.0 1 30 110
T8 2.0 <1 3S 110
1 T9 -1.3 <1 66 i:0
710 3.3 <1 64 130
ill 4.0 <1 94 HO
,
> *
t * >* m
« ^v 0 -v "7J
J ^0 ^ to -H
= -js r. E -
V .*£>-- O
*- "3 - -3 - «
** y c r. -/^
TJ5 2 & "^ -3
os"? IT w-« ii-^.
i-H «-2 i J! 3 55 4 if
7.1 53 - SO
;.o 8ii - s:o
6.7 270 - 130
7.0 233 - 160
".9 211 - i:0
7.7 1470 - 1080
7.6 256 - 190
7.6 250 - 190
7.S ZSb - 200
7,8 411 - 300
8.1 31S - 190
ypj - - - ~i \ rin^D ...
TP8 - , 4 47 270
TP2 - 14 150 820
TRP - <1 160 310
7.3 7S4 - 490
7.3 2680 - 2270
1 1200 .- 720
Al Ca Cl Cu
nj;/t ng/l nj/i mg/t
Fc ft Fc
uis. undis. total X Mg
r;/^ mg/l Bg/l BB/I ag/t
<0.5 20 <1 <0.0250 20
0.05 - - . 27 g
0.06 - - 12 3.4
-------
Table B-10. KATtR ANALYSIS DATA I'OR JUNC 19T4,
Ml
«!>,» »~
V. *1 -V fc.
m ..* *) w B
xC = O »
0 M t_' - U O
- - .3 a C ~*
=. - OLjrs'J-Sn
3 »c 2 ? S if 3 3
TI 2.0 -t i" j:
T: 13 <1 42 340
T3 4.5 2 21 1JO
T4 3.5 1 IS 78
T5 3.0
«j * ** 1/1
it *. 0 V. -3
j e* « M -
c -3 a r, m
o .-. 5 -< o
fc> -5 T . *
u- u e wi wi
-<3in y-3 ~-3
o j: s--» s.-« ««
C.5 8 3 O O O O tt
pti viuaiom r-« HE
7.2 42 - 45
7. 1 670 - 530
6.6 270 - 180
6.5 172 - 100
7.0 90-44
7.6 1440 - 1100
7.2 132 - 42
6.8 172 - 110
7.1 190 - 130
7.0 370 - 250
7.6 230 - 130
7.3 2500 - 2400
6.8 680 - 400
Al Ca Cl Cu
raj/t Big/ i mC/Z ne/l
1200 72
3.4 18 <0.1 290 6.0
00
-------
APPENDIX C
EDNA MINE SITE - SATURATED SOIL PASTE AND PLANT NUTRIENT ANALYSES
Table C-l. SATURATED PASTE ANALYSES OF SPOIL SAMPLES - EDNA MINE.
Sample
no.
NSI
0-2
2-4
NSII
0-4
NSIII
0-2
2-4
MSI
0-2
2-4
MS 1 1
0-2
2-4
MSI 1 1
0-2
2-4
SSI
0-4
SSII
0-2
2-4
pH
8.2
8.0
8,1
8.2
8.1
8.0
8.1
8.2
8.1
7.9
8.1
8.1
7.8
7.8
Cond.
2979
3191
4475
3967
3402
3699
3826
1186
1539
3247
3360
3826
1765
3064
Ca
ppm
45
50
42
52
41
42
46
11
15
47
39
42
20
49
Mg
ppm
122
226
320
270
247
342
290
82
107
207
247
335
116
182
Na
ppm
32
41
209
41
57
27
28
9
18
16
23
31
14
27
K
ppm
32
33
44
24
35
31
31
21
23
31
29
27
12
19
C03
ppm
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0,0
0.0
0.0
0.0
0.0
HC03
ppm
193
162
199
280
149
181
149
187
174
162
212
168
168
143
Cl
ppm
20
15
15
15
15
15
15
15
15
15
15
15
15
15
so4
ppm
590
670
1000
820
800
850
830
151
180
710
690
820
320
640
N03
ppm
53
87
115
77
99
81
74
9
65
12
6
130
37
99
micro-mohs/cm.
87
-------
Table C-2. SATURATED PASTE ANALYSES OF DRILL
CUTTINGS AND NATIVE SOIL - EDNA MINE.
Sample
no.
DC- 0-10
DC- 10- 20
DC-20-30
DC-30-40
DC-40-50
soil
pH
8.1
8.1
8.0
8.0
8.3
8.1
Cond.
2753
2372
3600
3374
2753
339
Ca
ppm
34
31
50
44
28
3
-Mg
ppm
140
130
107
227
205
9
Na .
ppm
83
77
71
103
79
13
K
ppm
-22*
16
46
51
58
11
co3
ppm
0.0
0.0
0.0
0.0
0.0
0.0
HC03
ppm
168
93
162
311
206
124
Cl
15
8
15
75
15
20
S04
ppm
420
390
700
740
470
30
N03
ppm
223
136
74
43
99
53
*micro-raohs/cm.
Table C3. PLANT NUTRIENT ANALYSES OF SPOIL SAMPLES - EDNA MIKE.
Sample
no.
NSI
0-2
2-4
NSI I
0-4
NSI 1 1
0-2
2-4
MSI
0-2
2-4
MSI I
0-2
2-4
MSI 1 1
0-2
2-4
SSI
0-4
SSII
0-2
2-4
pH
7.5
7.4
7.2
6.6
7.4
7.3
7.5
7.8
7.7
7.5
7.1
7.5
7.5
7.1
O.M.
3.8
4.6
3.1
4.8
4.0
3.9
3.1
3.6
3.9
3.0
3.4
6.1
5.9
3.5
Lime
Med
Med
Med
Med
Med
Med
Med
Med
Med
Med
Med
Med
Med
Mod
P
ppm
2
2
3
7
2
7
4
0
0
2
4
1
2
4
K is
ppm
124
121
140
104
128
128
143
136
149
146
120
93
85
93
I03~N
ppm
4
6
9
5
7
8
5
1
6
2
0
9
3
8
Zn
ppm
15.80
19.60
17.80
8.30
7.50
18.00
16.48
12.96
21.60
8.30
9.30
16.60
7.20
8.38
Fe
ppm
30.
45.
71.
117.
46.
69.
76.
37.
45.
39.
Texture
0
0
0
0
0
0
0
6
0
0
27.8
27.
6
35.0
57.0
Sandy
Sandy
Sandy
Sandy
Sandy
Clay
Clay
issa
Clay
Sandy
Sandy
Sandy
Sandy
Sandy
clay
clay
clay
clay
clay
clay
clay
clay
clay
clay
'insufficient sample.
88
-------
Table C-4. PLANT NUTRIENT ANALYSES OF DRILL
CUTTINGS AND NATIVE SOIL - EDNA MINE.
Sample
no.
DC- 0-10
DC-10-20
DC- 20- 30
DC-30-40
DC- 40- 50
soil
pH
7.7
7.8
7.5
7.5
7.6
6.6
O.M.
3.0
1.7
3.6
3.2
5.0
4.3
Lime
Med
Med
Med
Med
Med
Med
P
ppm
0
0
0
0
0
6
K
ppm
108
70
133
144
151
301
ppm
16
8
7
8
7
3
Zn
ppm
39,00
7.40
29.00
80.00
31.60
1.70
Fe
ppm
30.4
20.4
29.9
37.6
45.0
44.4
Texture
Sandy
Sandy
Sandy
Sandy
Sandy
Sandy
clay
clay
clay
clay
clay
clay
loam
loam
89
-------
APPENDIX D
NAVAJO MINE SITE - SATURATED SOIL PASTE AND PLANT NUTRIENT ANALYSES
Table D-l. SATURATED SOIL'PASTE ANALYSES OF
SPOIL AND OVERBURDEN -*NAVAJO MINE.
Sample
R-l
R-2
R-3
R-4
R-5
R-6
FBI
FB2
FB3
pH
8.1
8.1
8.0
7.9
4.6
7.8
8.2
8.1
7.9
Cond.a
3600
2217
4744
5224
11873
4024
9092
11916
7158
Ca
ppm
34
22
34
41
35
24
36
41
44
Mg
ppm
140
190
275
307
831
147
220
297
170
Na
ppm
500
218
890
857
2150
644
1840
2277
1271
K
ppm
25
16
29
33
24
30
21
53
34
3
ppm
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
HCO-
ppm
174
130
168
162
19
112
634
734
454
Cl
ppm
15
10
50
40
55
35
55
20
20
S04
ppm
740
270
930
1230
2340
670
1500
1750
1220
ppm
189
170
121
170
713
409
360
1829
744
micro-mobs/on.
Samples R-l through R-6 are
FB2, and FB3 are composited
surface spoil samples. Samples FBI,
samples of fresh overburden.
Table D-2. PLANT NUTRIENT ANALYSES OF
SPOIL AND OVERBURDEN - NAVAJO MINE.
Sample
no.
R-l
R-2
R-3
R-4
R-5
R-6
FBI
FB2
FB3
pH
7.3
7.9
7.5
7.3
4.3
7.4
7.1
6.9
7.0
%
O.M.
1.3
0.2
2.0
2.6
6.5
0.6
1.1
4.5
3.9
Lime
Med
Med
Med
Low
Low
Low
low
Low
Med
P
ppm
2
5
5
5
7
1
4
9
6
K
ppm
101
73
206
190
153
'289
148
181
194
NO.-N
ppm
12
9
11
20
98
48
30
160
90
Zn
ppm
0,59
0,16
1.58
1.03
17.80
0.49
2.04
6.26
3.40
Fe
ppm
9.9
4.4
16.4
19.7
272.0
7.1
134.0
124.0
74.0
Texture
Sand}'
Sandy
Sandy
Sandy
Sandy
Clay
Clay
Clay
Sandy
clay
loam
clay
clay
clay
clay
loam
loam
loam
loam
loam
90
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APPENDIX E
IDARADO MINE SITE - SATURATED SOIL PASTE AND PLANT NUTRIENT ANALYSES
Table E-l. SATURATED PASTE ANALYSES*OF TAILINGS - IDARADO MINE.
Sample
no.
4-2
5-2
5-3
5-5
5-6
6-2
6-5
2-1
2-2
3-2
pH
7.
7.
7.
t
*
7.
8.
7.
7.
7.
6
5
6
6
6
0
7
8
9
7.6
Cond.!
2612
2372
2435
3078
2428
537
2047
2499
2442
2824
Ca Mg
ppm ppm
52 55
5* 18
51 55
62 122
52 76
6 16
39 15
54 34
46 39
52 92
Na
ppm
61
49
58
39
29
6
64
12
64
54
K
ppm
37
29
48
24
33
12
58
23
29
59
Cwf* riL*U wl
ppm ppm ppm
0.0 87
0.0 81
0.0 87
0.0 93
0.0 99
0,0 118
0.0 105
0.0 105
0.0 171
0.0 93
15
15
15
15
15
10
20
10
25
35
ppm
430
480
450
440
550
61
240
450
370
590
ppm
112
96
105
558
50
6
3
53
130
43
*micro-mohs/cm.
Table
Sample
no.
4-2
5-2
5-3
5-5
5-6
6-2
6-5
2-1
2-2
3-2
E-2.
pH
7.
7.
7.
7.
7.
7.
7.
7.
7.
7.
4
4
5
4
3
8
5
6
7
5
PLANT NUTRIENT ANALYSES OF
O.M.
0.7
0.3
0.4
0.3
0.4
0.2
1.4
0.3
0.2
1.2
P
Lime ppm
Med 0
Med 1
Med 0
Med 3
Med 0
Med 1
Med 0
Med 2
Med 6
Med 1
K
ppm
36
25
39
25
24
21
36
29
58
70
ppm
2
7
6
36
3
0
0
3
12
10
TAILINGS - IDARADO MINE.
Zn Fe
ppm Ppm
122,0 25.
114,0 14.
34.8 +9.
167.0 22.
148.0 12.
150.0 16.
41.0 23.
230.0 12.
310.0 41.
211.0 64.
Texture
3
4
99
5
9
9
2
0
8
,4
issa
Sand
Sand
Loamy
Loamy
Loamy
Loamy
Loamy
Sandy
Silty
sand
sand
sand
sand
sand
loam
loam
Insufficient sample.
91
-------
APPENDIX F
COLUMN LEACHING DATA
Table F-l. DESCRIPTIONS OF EDNA MINE SAMPLES USHD IN LEACHING TESTS.
Sample Description
NSI Sample formed by compositing samples every 15 cm to a depth
of 120 cm near the up-slope limit of mining on the north
and of the Edna spoils. Gray and black shale fragments
with some sandstone. Shales appear to crumble and decom-
pose readily in water. Bulk volume of sample is 1293 cm
and dry weight is 1829 gin. Length of column is 35 cm.
Conductivity of saturated paste = 3000 ymohs/cm.
MSII Sample formed by compositing samples every 15 cm between
the depths of 60 and 120 cm near the center of mined area.
Gray and black shale fragments. Relatively more stable in
water than other samples. Bulk volume of sample is 1293 cm
and dry weight is 1941 gm. Length of column is 35 cm.
Conductivity of saturated paste = 1540 pmohs/cm.
SSI Sample formed by compositing samples every 15 cm to a depth
of 120 cm at the south end of mined area disturbed before
1962. Gray and black shale fragments which crumble readily
in water. Bulk volume of sample is 1367 cm and dry weight
is 1922 gm. Length of column is 37 cm. Conductivity of
saturated paste = 3830 ymohs/cm.
DC-10-20 Sample formed by compositing samples between 3 and 6 meters
below the surface from four locations along the highwall.
Fraction larger than 0.351 mm used in column. Mostly light
tan shale and siltstone with some gray and black shale.
Bulk volume is 1960 cm and dry weight is 1320 gm. Length
of column is 26 cm. Conductivity of saturated paste =
2370 pmohs/cm.
92
-------
Table F-l. DESCRIPTIONS OF EDNA MINE SAMPLES USED IN LEACHING TESTS.
(continued)
Sample Description
DC-30-40 Sample formed by compositing samples between 10 and 13
meters below the surface from four locations along the
highwall. Fraction larger than 0.351 mm used in column.
3
Gray and black shale cuttings. Bulk volume is 1071 cm
and dry weight is 1496 gm. Length of column is 29 cm.
Conductivity of saturated paste = 3370 ymohs/cm.
DC-40-SO Sample formed by compositing samples between 13 and 16
meters below the surface from four locations along the
highwall. Fraction larger than 0.351 mm used in column.
3
Gray and black shale cuttings. Bulk volume is 997 cm
and dry weight is 1439 gm. Length of column is 27 cm.
Conductivity of saturated paste = 2750 ymohs/cm.
93
-------
Table F-2. LEACHING DATA FOR COLUMNS OF
SPOILS AND DRILL CUTTINGS - EDNA MINE.
Volume of
leachate
Sample can3 pH
NSI 279
642
811
2761
3174
3487
3821
4275
5300
5690
6057
MSI I 931
1152
1823
3367
5127
8718
9302
SSI 271
513
2259
4006
6966
12984
14270
7.5
7.8
8.1
8.0
7.9
8.0
8.0
7.9
8.0
8.0
8.0
7.1
7.8
8.0
7.8
8.2
8.3
8.2
7.4
7.4
7.6
7.8
7.7
8.0
7.9
Specific
conduct .
ymohs/cm
3250
2330
816
510
333
260
280
240
237
222
204
814
300
350
187
130
120
110
3850
3820
2030
500
500
150
120
Volume of
leachate
Sample crn^ pH
DC-10-20 101
656
3368
3426
6331
7899
8918
10368
10638
DC- 30-40 133
2822
3601
5407
6109
6258
6319
6499
DC-40-50 639
1009
1353
1688
2016
2520
3383
5079
6697
7121
7313
7402
7460
7.7
7.9
7.8
8.0
8.0
8.0
7.9
7.9
-
7.2
7.7
7.8
7.8
7.9
8.0
8.0
8.0
7.9
8.0
8.0
7.9
7.9
8.0
7.9
8.0
8.1
8.1
8.1
8.1
8.2
Specific
conduct .
ymohs/cm
980
1140
230
230
126
91
78
76
74
2860
930
210
240
161
202
240
222
1900
910
560
370
303
260
190
150
140
170
225
250
278
94
-------
Table F-3. DESCRIPTION OF NAVAJO MINE SAMPLES USED IN LEACHING TESTS.
Sample Description
FBI Sample formed by compositing samples between 2 and 5 meters
below surface and above No. 8 seam in Barber pit. Fraction
larger than 0.351 mm used in column. Tan shale and silt-
stone with some yellow clay nodules and some gray shale.
Crumbles readily in water. Bulk volume of sample is
3
1182 cm and dry weight is 1467 gm. Column length 32 cm.
Conductivity of saturated paste = 9100 ymohs/cm.
FB2 Sample formed by compositing samples between the No. 8
and No. 7 seams in the Barber pit. Fraction larger than
0.351 mm used in column. Light gray shale with some tan
3
shale and clay. Bulk volume of sample is 1182 cm and
dry weight is 1727 gm. Column length is 32 cm. Conductiv-
ity of saturated paste = 11900 ymohs/cm.
FB3 Sample formed by compositing samples between the No. 7 and
No. 6 seams in the Barber pit. Fraction larger than 0.351
mm used in column. Light gray shale with some tan shale
3
and clay. Bulk volumn of sample is 1000 cm and dry weight
is 1265 gm. Length of column is 27 cm. Conductivity of
saturated paste = 7200 ymohs/cm.
95
-------
Table F-4. LEACHING DATA FOR COLUMNS OF OVERBURDEN - NAVAJO MINE.
Volume of
leachate
Sample cm3
FBI 457
729
1007
1891
2511
3220
3602
5644
7226
7913
8254
8492
9903
10345
12005
14508
FB2 175
2776
4794
5501
7756
pH
7,2
7.4
7.3
7.2
7.2
7.2
7.2
7.1
7.2
7.6
7.5
7.5
7.4
7.6
7.7
8.0
6.7
6,9
7.2
7.4
7.4
Specific
conduct .
umohs/cm
8200
8700
8000
6900
4100
3400
3100
2630
2150
2340
2380
2220
1300
1250
1040
493
7100
3640
1760
1960
966
Volume of
leachate
Sample cm3
FB2 8187
8543
8880
9073
11049
12528
FB3 1966
4261
4488
5017
5334
5631
6073
7946
9050
9831
pH
7.4
7.5
7.6
7.6
-
8.0
6.9
6.9
7.0
7.0
7.2
7.3
7.3
-
-
8.0
Specific
conduct .
ymohs/cm
1140
1080
1000
950
470
470
4650
1920
2170
1970
1840
1670
1450
625
377
384
96
-------
APPENDIX G
INFILTRATION DATA
Table G-l. INFILTRATION DATA AT EDNA MINE SITE.
Cumulative infiltration, cm
Time
min.
0.0
0.5
1.0
1.5
2.0
3.0
4.0
6.0
8.0
10.0
15.0
20.0
30.0
45.0
60.0
90.0
120.0
150.0
Graded spoils
#1
0.0
1.2
1.7
1.8
1.8
1.83
1.9
-
2.1
2.3
2.3
-
2.5
-
3.1
3.5
3.8
-
Graded spoils
#2
0.0
0.4
0.8
-
1.0
1.4
1.7
2.2
-
2.7
3.3
-
4.4
-
6.2
7.9
9.3
10.5
Native soil
#1
0.0
1.0
1.6
1.9
2.2
2.8
3.4
4.3
-
5.9
8.1
10.0
-
-
-
-
-
-"
Native soil
#2
0.0
0.8
1.5
1.7
2.0
2.4
3.0
3.8
-
5.1
6.4
-
9.8
12.8
15.6
-
-
97
-------
Table G-2. INFILTRATION DATA AT NAVAJO MINE SITE.
Cumulative infiltration, cm
Time
min.
0.0
0.5
1.0
2.0
4.0
5.0
6.0
8.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
60.0
70.0
90.0
100.0
130.0
160.0
Sprinkler
plot - 1
0.0
0.5
0.8
0.9
-
1.1
-
-
1.4
-
1.65
-
-
-
2.3
-
-
3.0
-
3.7
4.2
5.2
Sprinkler
pJLot - 2
0.0
0.5
0.8
0.9
-
1.2
-
-
1.65
-
2.0
-
-
-
2.7
-
3.0
-
3.6
-
-
-
Drip Irrig.
plot - 1
0.0
0.4
0.45
0.51
0.51
-
0.56
-
0.64
-
-
-
1.0
-
-
-
-
-
1.5
-.
1.65
2.4
Native
soil
0.0
1.3
1.8
2.4
3.3
-
3.9
4.3
4.6
5.5
6.2
7.0
7.8
8.6
9.3
10.0
-
-
-
-
-
-
98
-------
Table G-3. INFILTRATION
DATA AT IDARADO SITE.
Cumulative infiltration, cm
Time Tailings pond Tailings pond
min . #5 #6
0.0
0.5
1.0
1.25
1.5
2.0
4.0
6.0
10.0
15.0
30.0
60.0
90.0
120.0
150.0
0.0
1.1
1.7
1.8
-
2.3
3.1
3.6
4.0
4.3
4.9
5.9
7.0
8.1
9.5
0.0
0.8
1.2
-
1.4
1.4
1.6
1.8
2.0
2.3
3.0
3.6
4.1
4.5
-
99
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-670/2-75-048
3. RECIPIENT'S ACCESSION-NO.
». TITLE AND SUBTITLE
WATER QUALITY CONTROL IN MINE SPOILS
UPPER COLORADO RIVER BASIN
5. REPORT DATE
June 1975; Issuing Date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
David B. McWhorter, Rodney K. Skogerboe, and
Gaylord V. Skogerboe
8. PERFORMING ORGANIZATION REPORT NO.
3. PERFORMING ORGANIZATION NAME AND ADDRESS
Colorado State University
Fort Collins, Colorado 80523
10. PROGRAM ELEMENT NO.
1BB040; ROAP 21BDU: Task 02
11. JEaMXKAOOVGRANT NO.
R802621
12. SPONSORING AGENCY NAME AND ADDRESS
National Environmental Research Center
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
IS. SUPPLEMENTARY NOTES
16. ABSTRACT
The purpose of this study was to identify potential water quality problems associated
with runoff and percolation through mine spoils at selected sites in the Upper
Colorado River Basin. The results show that the production of soluble salts from
mine spoils into receiving waters is probably the most significant water quality
problem that can be expected. No significant release of heavy metals was observed
in the coal mine spoils studied. Some significant heavy metal concentrations were
observed in the stream below the tailings disposal area from a copper-lead-zinc mill.
A portion of these metals are contributed by the tailings, but a variety of old mines
and mine dumps also make a contribution. The quality of percolate and runoff from
spoils was found to correspond to the constituents of extracts prepared from saturated
pastes of the spoil material. A method of estimating salt production into receiving
waters was derived and found to agree very well with measured salt pickup at one coal
site. The minimum quantities of salts that will eventually be released from the
spoils studied are estimated.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
COSATI Field/Group
Coal mines, *Strip mining, Waste disposal,
*Drainage, Mine waters, Spoil, *Water
pollution, Water quality, *Ground water,
Water chemistry, Salinity, Soil chemistry,
Solubility, Runoff, Tailings
Strip mine wastes,
Upper Colorado River
Basin
081
13B
18. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (ThisReport)
UNCLASSIFIED
21. NO. OF PAGES
108
20. SECURITY CLASS (Thispage)
UNCLASSIFIED
22. PRICE
EPA Form 222O-1 (9-73)
100
#U.$.60WMMEIITr«IIITIIIGOmCE: 1975-657-593/5390 Region No. 5-11
------- |