United States
           Environmental Protection
           Agency
Office of Water
(4303)
EPA821-B-01-012
December 2001
FINAL
vvEPA    Development Document for Final Effluent
           Limitations Guidelines and Standards for
           the Western Alkaline Coal Mining
           Subcategory

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                                       EPA821-B-01-012
          DEVELOPMENT DOCUMENT
       FOR FINAL EFFLUENT LIMITATIONS
     GUIDELINES AND STANDARDS FOR THE
WESTERN ALKALINE COAL MINING SUBCATEGORY
                 December 2001
                 Office of Water
          Office of Science and Technology
          Engineering and Analysis Division
        U.S. Environmental Protection Agency
             Washington, DC 20460

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                                  Development Document - Western Alkaline Coal Mining Sub category
                               Acknowledgments
       This document was developed under the direction of William A. Telliard and John linger
of the Engineering and Analysis Division (BAD) within the U.S. Environmental Protection
Agency's (EPA) Office of Science and Technology (OST). This manual was made possible
through the efforts of a Western Coal Mining Work Group (WCMWG) consisting of
representatives from the Office of Surface Mining Reclamation and Enforcement (OSMRE), the
Western Interstate Energy Board (WIEB), the National Mining Association (NMA), industry,
and consulting firms. EPA gratefully acknowledges the contributions of the WCMWG for the
preparation and submittal of technical information packages, reports, and performance in support
of the proposed rulemaking.  EPA also wishes to thank DynCorp Information and Enterprise
Technology for its invaluable support.
                                    Disclaimer

       The statements in this document are intended solely as guidance. This document is not
intended, nor can it be relied upon, to create any rights enforceable by any party in litigation with
the United States.  EPA may decide to follow the guidance provided in this document, or to act
at variance with the guidance, based on its analysis of the specific facts  presented. This guidance
is being issued in connection with amendments to the Coal Mining Point Source Category.
The primary contact regarding questions or comments on this document is:

William A. Telliard
Engineering and Analysis Division (4303)
U.S. Environmental Protection Agency
Ariel Rios Building, 1200 Pennsylvania Avenue
Washington, DC   20460
Phone: 202/260-7134
Fax: 202/260-7185
email: telliard.william@epamail.epa.gov
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                                  Development Document - Western Alkaline Coal Mining Sub category
                                Table of Contents
Acknowledgments  	/
Table of Contents	/'//'
List of Figures	  vii
List of Tables  	ix
Acronyms 	xi
Glossary  	xiii
Executive Summary	 xix
1.0    BACKGROUND

1.1    Legal Authority                                                             1-1

1.2    Regulatory History  	1-1

       1.2.1  Clean Water Act	1-4
       1.2.2  Surface Mining Control and Reclamation Act  	1-6
       1.2.3  State Regulatory Guidelines for Sediment Control	1-11



2.0    INDUSTRY CHARACTERIZATION

2.1    Location and Production                                                     2-1

2.2    Environmental Conditions 	2-6
       2.2.1  Temperature	2-6
       2.2.2  Precipitation	2-6
       2.2.3  Erosion Prone Soils 	2-8
       2.2.4  Hydrology and Sedimentation	2-8
       2.2.5  Vegetation 	2-10
       2.2.6  Watershed Runoff Characteristics	2-10
       2.2.7  Cumulative Effect 	2-11
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3.0    BEST MANAGEMENT PRACTICES

3.1    Sediment                                                                   3-1

3.2    Sedimentation Pond Use and Impacts in Arid and Semiarid Regions            3-1
       3.2.1  Surface Disturbance	3-2
       3.2.2  Water Impoundment  	3-3
       3.2.3  Sediment Retention  	3-6
       3.2.4  Scouring and Seeps  	3-6

3.3    Sediment Control BMPs                                                     3-7
       3.3.1  Managerial BMPs  	3-9
       3.3.2  Structural BMPs	3-10
       3.3.3  BMP Implementation	3-13

3.4    Prediction Models for BMP Design and Implementation 	3-21
       3.4.1  Revised Universal Soil Loss Equation (RUSLE)  	3-22
       3.4.2  SEDCAD	3-24
       3.4.3  SEDIMOT II 	3-25
       3.4.4  HEC-6  	3-26
       3.4.5  MULTSED	3-26
4.0    BENEFITS OF SEDIMENT CONTROL BMPS

4.1    Environmental Benefits	4-1
       4.1.1  Source Control	4-1
       4.1.2  Minimizes Disturbance to the Hydrologic Balance	4-2
       4.1.3  Maintains Natural Sediment Yield  	4-3
       4.1.4  Minimizes Surface Disturbance	4-4
       4.1.5  Encourages Vegetation 	4-5
       4.1.6  Improves Soil and Promotes Soil Conservation  	4-5
       4.1.7  Addresses Site-Specific Environmental Conditions 	4-6
       4.1.8  Stabilizes Landforms	4-6
       4.1.9  Minimizes Disruptions to Flow Regime  	4-7

4.2    Implementation and Enforcement Benefits	4-8
       4.2.1  Implements Existing Requirements	4-8
       4.2.2  Improves Monitoring and Inspection Capability	4-8
       4.2.3  Provides Control and Treatment Flexibility  	4-9
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5.0    CASE STUDIES

5.1    Case Study 1 (Western Coal Mining Work Group, 1999c)                      5-2
       5.1.1  Modeling Results	5-4
       5.1.2  Cost 	5-7

5.2    Case Study 2 (Western Coal Mining Work Group, 2000a)                     5-10
       5.2.1  Modeling Results	5-11
       5.2.2  Costs	5-15

5.3    Case Study 3 (Western Coal Mining Work Group, 2000b)                     5-21
       5.3.1  Modeling Results	5-22
       5.3.2  Costs	5-25

5.4    Case Study 4 (Bridger Coal Company, Jim Bridger Mine)	5-27
       5.4.1  Justification of Alternate Sediment Controls	5-27
       5.4.2  Description of Alternate Sediment Control Techniques 	5-29
       5.4.3  Alternate Sediment Control Design	5-30
       5.4.4  Monitoring Program  	5-35
       5.4.5  Data Reduction  	5-36
       5.4.6  Data Analysis	5-37
       5.4.7  Summary  	5-44

5.5    Case Study 5 (Water Engineering and Technology, Inc., 1990)                 5-45
       5.5.1  Background Sediment Yield  	5-46
       5.5.2  Evaluation of Watershed Computer Models  	5-49
       5.5.3  Rainfall Simulation Data Collection 	5-51
       5.5.4  Calibration and Validation of the MULTSED Model	5-61
       5.5.5  Evaluation of Alternative Sediment Control Techniques 	5-61
6.0    REFERENCES	  6-1
APPENDIX A:     Wyoming Coal Rules and Regulations, Chapter IV
APPENDIX B:     Wyoming Guideline No. 15
APPENDIX C:     19 NMAC 8.2 Subpart 20 Section 2009
APPENDIX D:     Mine Modeling and Performance Analysis - Model Input and Output
                   Data
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List of Figures

SECTION i.o
Figure la:    Timeline of Selected Mining Regulations Affecting the
             Coal Mining Industry  	1-3
SECTION 2.0
Figure 2a:    Coal Producing Areas                                               2-2

SECTION 5.0
Figure 5a:    Mine Model Approach: A Method for Evaluating Erosion
             and Sediment Control Options                                       5-5
Figure 5b:    Initial Receiving Stream TSS Data                                   5-28
Figure 5c:    Sediment Yield vs. Water Yield 	5-43
Figure 5d:    Navajo Mine Sediment Yield vs. Plot Slope                           5-63
Figure 5e:    Navajo Mine Sediment Yield vs. Percent Ground Cover	5-63
Figure 5f:    Navajo Mine Sediment Yield vs. Slope Length	5-64
Figure 5g:    Navajo Mine Sediment Yield vs. Depression Storage	5-64
Figure 5h:    McKinley Mine Sediment Yield vs. Plot Slope                        5-65
Figure 5i:    McKinley Mine Sediment Yield vs. Plot Slope                        5-65
Figure 5j:    McKinley Mine Sediment Yield vs. Slope Length  	5-66
Figure 5k:    McKinley Mine Sediment Yield vs. Percent Ground Cover 	5-66
Figure 51:    McKinley Mine Sediment Yield vs. Depression Storage 	5-67
Figure 5m:   Black Mesa/Kayenta Mines Sediment Yield vs. Plot Slope	5-67
Figure 5n:    Black Mesa/Kayenta Mines Sediment Yield vs. Plot Slope	5-68
Figure 5o:    Black Mesa/Kayenta Mines Sediment Yield vs. Slope Length 	5-68
Figure 5p:    Black Mesa Mine Sediment Yield vs. Slope Length	5-69
Figure 5q:    Black Mesa/Kayenta Mines Sediment Yield vs. Percent
             Ground Cover	5-69
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List of Tables


SECTION 2.0

Table 2a:    United States Coal Production by Region (short tons)                   2-3

Table 2b:    Operation and Production Statistic of Potentially Affected Coal
             Mines in the Arid and Semiarid Coal Producing Region	2-4

Table 2c:    Average Annual Precipitation in Arid and Semiarid Coal States	2-7


SECTION 3.0

Table 3a:    Area Disturbance and Watershed Drainage of Sedimentation Ponds
             at Four Western Mine Operations	3-3

Table 3b:    Examples of Managerial Sediment and Erosion Control Practices 	3-10

Table 3c:    Examples of Structural Best Management Practices	3-11

Table 3d:    Summary of Coal Quality Data in Western and Eastern Coal
             Regions 	3-20


SECTION 5.0

Table 5a:    Representative Mine Characteristics and Model Input Information       5-3

Table 5b:    Comparison of Hydrology and Sedimentology Results  	5-8

Table 5c:    Cost of Compliance with Numeric Limitations vs. Cost to Implement
             Alternative  Sediment Control BMPs                                  5-9

Table 5d:    Comparison of Hydrology and Sedimentology Results  for the
             Intermountain Reclamation Model  	5-13

Table 5e:    Comparison of Hydrology and Sedimentology Results  for the
             Northern Plains Reclamation Model	5-14

Table 5f:     Model Mine Design Criteria                                        5-16


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Table 5g:     Cost of Meeting Numeric limits vs. Cost to Implement Alternative
             Sediment Control BMPs for the Intermountain Model Mine	
Table 5h:     Cost of Meeting Numeric limits vs. Cost to Implement Alternative
             Sediment Control BMPs for the Northern Plains Model Mine ....
. 5-19
. 5-20
Table 5i:     Comparison of Hydrology and Sedimentology Results  	5-24

Table 5j:     Cost of Sedimentation Pond System vs. Cost to Implement Alternative
             Sediment Controls	5-26

Table 5k:     Pre-mining Surface Water Quality Data                              5-31

Table 51:     Existing Database, Undisturbed TSS Concentration Data  	5-34

Table 5m:    Order of Simulation of Sediment Control Best Management Practices .  . 5-35

Table 5n:     Example Water and Sediment Yield Data (1984-1998)                  5-38

Table 5o:     Measured Sediment Yields at Navajo and McKinley Coal Mines  	5-47

Table 5p:     Ranking of Five Computer Models                                   5-50

Table 5q:     Rainfall, Runoff and Sediment Yield Data for Navajo Mine             5-52

Table 5r:     Rainfall, Runoff and Sediment Yield Data for McKinley Mine          5-55

Table 5s:     Rainfall, Runoff and Sediment Yield Data for Black Mesa and
             Kayenta Mines                                                    5-58
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                                    Acronyms

acre-ft: acre-feet
ASCM: Alternative Sediment Control Measure
BAT: Best Available Technology
BMP:  Best Management Practice
BPT: Best Practicable Control Technology Currently Available
BTCA: Best Technology Currently Available
Btu: British thermal unit
cfs: cubic feet per second
CHIA: Cumulative Hydrologic Impact Assessment
CWA: Federal Water Pollution Control Act of 1972; the Clean Water Act
DEQ: Department of Environmental Quality
EASI: Erosion and Sediment Impacts Model
EPA: U.S. Environmental Protection Agency
FEIS: Final Environmental Impact Statement
LQD: Land Quality Division
mg/L: milligrams per liter
ml/L: milliliters per liter
MMD: New Mexico Mining and Minerals Division
MUSLE: Modified Universal Soil  Loss Equation
NMA: National  Mining Association
NOV: Notice of Violation
NPDES: National Pollution Discharge Elimination System
NRCS: Natural Resource Conservation Service
NSPS: New Source Performance Standard
OSMRE: Office of Surface Mining and Reclamation Enforcement
PHC: Probable Hydrologic Consequence

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RUSLE: Revised Universal Soil Loss Equation
SCS: Soil Conservation Service
SEDCAD: Sediment, Erosion, Discharge by Computer Aided Design
SEDIMOT II: Sedimentology by Distributed Model Treatment
SMCRA: Surface Mining Control and Reclamation Act
SS: Settleable Solids
TSS: Total Suspended Solids
DOT: Department of Transportation
USDA: United States Department of Agriculture
USLE: Universal Soil Loss Equation
WIEB: Western Interstate Energy Board
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                                      Glossary
Alkaline Mine Drainage: Mine drainage which, before any treatment, has a pH equal to or
       greater than 6.0 and a total iron concentration of less than 10 mg/L.

Approximate Original Contour: Surface configuration achieved by backfilling and grading of
       mined areas so that the reclaimed land surface closely resembles the general surface
       configuration of the land prior to mining and blends into and complements the drainage
       pattern of the surrounding terrain.

Arid and semiarid area: An area of the interior western United States, west of the  100th
       meridian west longitude, experiencing water deficits, where water use by native
       vegetation equals or exceeds that supplied by precipitation. All coalfields located in
       North Dakota west of the 100th meridian west longitude, all coal fields in Montana,
       Wyoming, Utah, Colorado, New Mexico, Idaho, Nevada, and Arizona, The Eagle Pass
       field in Texas, and the Stone Canyon and the lone fields in California are in  arid and
       semiarid areas (30 CFR Ch. VII § 701.5).

Armoring: Lining drainage channels with rock to limit re-transport of the channel bottom.

Arroyo: A term applied in the arid and semiarid regions of southwest United States to the small
       deep flat-floored channel or gully of an ephemeral stream or an intermittent  stream,
       usually with vertical or steeply cut banks of unconsolidated material at least 60 cm high.
       It is usually dry, but may be transformed into a temporary water-course or short lived
       torrent after heavy rainfall (Bates and Jackson,  1980).

Bank Carving: A form of erosion in which the foundation of the banks of a stream  or river are
       undermined due to an increase in flow rate causing the bank to fail.

Bank Slumping: See bank carving.

Berming: An engineering technique which creates a long mound of earth to control the flow of
       water.

Best Management Practice: Schedules of activities, prohibitions or practices,  maintenance
       procedures, and other management or operational practices to prevent or reduce the
       pollution of waters of the United States.

British Thermal Unit: The amount of heat needed to raise the temperature  of 1 pound of water
       by 1 degree Fahrenheit, approximately equal to 252 calories. The Btu is a convenient
       measure by which to compare the energy content of various fuels.
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Channel Head: The upper reaches of a stream where the kinetic energy of water is highest.

Channel Head-Cutting: Loss of sediment from the upper reaches of a stream.

Channel Bed: The sediment at the deepest portion of a stream.

Coal Surface Mine: A coal-producing mine that extracts coal that is usually within a few
       hundred feet of the surface. Earth and rock above the coal (overburden) is removed to
       expose the coal seam which is then excavated with draglines, bulldozers, front-end
       loaders, augering and/or other heavy  equipment. It may also be known as an area,
       contour, open-pit, strip, or auger mine.

Concentration of Contaminant: The amount of pollutant parameter proportional to the total
       volume.

Contour Furrowing:  A soil-loss prevention technique adapted to control sediment runoff. The
       sediment is plowed along the contour lines which helps impede water flow.

Disturbed Area: An area which has  been altered in generally an unacceptable manner by human
       or natural actions.

Diverting Runoff: An engineering technique to force water away from natural watercourses,
       allowing for reduction in water velocity and volume.

Dry wash: A wash (stream or gully)  that carries water only at infrequent intervals and for brief
       periods, as after a heavy rainfall.

Ephemeral Stream: A stream which flows only in direct response to precipitation  in
       the immediate watershed or in response to snow melt, and which has a channel bottom
       that is always above the prevailing water table.

Erosion: A natural process by the action of water, wind, and ice in which soil and rock material
       is loosened and removed.  The major factors affecting soil erosion are soil characteristics,
       climate, rainfall intensity and duration, vegetation or other surface cover, and
       topography.

Evapotranspiration: That portion of precipitation returned to the air through direct evaporation
       or by transpiration of vegetation.

Ferruginous: Of coals, minerals and rocks containing iron. Water running off such materials is
       usually rust colored, and will  tend to  be acidic.

Flash Flooding: A large surge of water runoff from a storm event. Flash floods are worsened
       by lack of vegetation or natural flow-retarding elements such as soils, lakes  or
       impoundments.

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Flow Naturally: The course of water unimpeded or altered by man-made activity or structures.

Fluvial: Relating to, or occurring in a river.

Fluvial Processes: The physical actions of water on sediments, changing and being changed by
       the results of those actions.

Fluvial Morphology: Landforms and structures created by the activity of water both in motion
       and at rest.

Forb: A broad-leaved herbaceous plant, as distinguished from grasses, shrubs and trees.

Geotextiles: Porous fabrics composed of woven synthetic materials. Geotextiles also are known
       as filter fabrics, road rugs, synthetic fabrics, constructions, or geosynthetic fabrics.

Grading: Cutting and/or filling land surfaces with heavy equipment to create a desired
       configuration,  slope or elevation.

Grass Filter Strips: Sections of land with planted grass to help retain eroding sediment.

Harvested Precipitation: The rainfall that is channeled by gutters or ditches to a storage area or
       for an immediate specific use.

Head-cut Erosion: The sudden change in elevation or knickpoint at the leading edge of a gully.
       Head-cuts can range from less than an inch to several feet in height, depending on  several
       factors. The formation and movement of a gully head-cut are often the dominant form of
       damage observed in an earth spillway.

High-Yield Storm: A rain storm with a large amount of impact.

Hydrophytic Vegetation: Water-loving vegetation requiring considerable water to survive.

Hydrologic Balance:  The relationship between the quality  and quantity of water inflow to,
       outflow from, and storage in a hydrologic unit such  as a drainage basin, aquifer, soil
       zone, lake or reservoir. A water budget that encompasses the dynamic relationships
       among precipitation, surface runoff, evaporation, and changes in surface water and
       ground water storage.

Infiltration: Surface water sinking into the sediment column as the first step towards becoming
       ground water.

Irrigation: Application of water to agricultural or recreational land for promoting plant growth.

Kinetic Energy: Energy contained by mass in motion. In particular, rapidly moving water will

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       have relatively high kinetic energy, allowing for the movement of large amounts of
       sediment (see turbulent flow).

Mass wasting: The movement of regolith downslope by gravity without the aid of a transporting
       medium. Mass wasting depends on the interaction of soils, rock particles and moisture
       content.

Morphology: The form and structure of the landscape, i.e., slope, errosional features, hills, etc.

Mulch: A temporary soil stabilization or erosion control practice where materials such as grass,
       hay, woodchips, wood fibers, or straw are placed on the soil surface. A natural or
       artificial layer of plant residue  or other materials  covering the land surface that conserves
       moisture, holds soil in place, aids in establishing  plant cover, and minimizes temperature
       fluctuations.

Non-consumptive retention: The impoundment of water without its extraction for other uses.

Non-process Area: The surface area of a coal mine that  has been returned to required contour
       and on which revegetation (specifically seeding or planting) work has commenced.

Perennial Rivers: Rivers which flow during particular seasons in a predictable manner.

Periodic Releases: An infrequent discharge of water either by design or by naturally intermittent
       precipitation.

Precipitation: The discharge of water, in liquid or solid  state, from the atmosphere, generally
       onto a land or water surface. The term "precipitation" is also commonly used to
       designate the quantity of water that is precipitated.  Forms of precipitation include
       drizzle, rainfall, glaze, sleet, snow, and hail.

Receiving Stream: A down-gradient stream that catches runoff from a mining area.

Reclaimed Area: A disturbed area that is restored by remediation activities to an acceptable
       condition.

Regolith: The layer or loose unconsolidated rock material, including soil, resting on bedrock,
       constituting the surface of most land.

Rill Erosion: Rill erosion is the removal of soil by concentrated water running through little
       streamlets, or head-cuts.

Riparian Habitat: Areas adjacent to rivers and streams that have a high density, diversity, and
       productivity of plant and animal species relative to nearby uplands.

Runoff:  That part of precipitation, snow melt, or irrigation water that runs off the land into

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       streams or other surface waterbody.

Runoff Event: In arid and semiarid areas, the majority of the annual precipitation occurs during
       infrequent rainfalls causing surface water runoff events that result in most of the erosion.

Scouring:  The clearing and digging action of flowing water, especially the downward erosion
       caused by stream water in sweeping away mud and silt from the stream bed and outside
       bank of a curved channel.

Sediment:  Soil and rock particles washed from land into  waterbodies, usually after significant
       rain. For the purpose of this document,  sediment  is all material transported by surface
       water drainage, including total settleable solids, suspended solids, and bedload.

Sediment Control Measures: Engineering and biological techniques and practices to control the
       quantity and location of sedimentation.

Sediment Imbalance: An abnormally high increase or decrease in sedimentation rates caused by
       some activity.

Sediment Yield: the sum of the soil losses minus deposition in macro-topographic depressions,
       at the toe of the hillslope, along field boundaries,  or in terraces and channels sculpted into
       the hillslope.

Sedimentation: The process of depositing soil particles,  clays, sand, or other sediments
       transported by flowing water.

Sedimentation Pond: A sediment control structure designed, constructed, and maintained to
       slow down or impound precipitation runoff that allows the water to drop its sediment
       load and reduce sediment concentrations at the point  source discharge.

Seep: A point where water oozes or flows from the earth.

Semiarid: Landscape characterized by scanty rainfall. Pertaining to a subdivision of climate in
       which the associated ecological conditions are distinguished by short grass and scrubby
       vegetation.

Sheet Erosion: The detachment of land surface material by raindrop impact and thawing of
       frozen grounds and its subsequent removal by overland flow.

Sodic: Pertaining to or containing sodium: sodic soil.

Soil Erodibility Factor: The inability of a soil to resist erosive energy of rains A measure of the
       erosion potential for a specific soil type based on  inherent physical properties such as
       particle size, organic matter, aggregate stability, and permeability.
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Soil Loss: that material actually removed from the particular hillslope or hillslope segment. The
       soil loss may be less than erosion due to on-site deposition in microtopographic
       depressions on the hillslope.

Steepness Factor: Combination factor of for slope length and gradient.

Terrace Levels: Sediment platforms within stream channels, where different volumes of water
       periodically flow.

Turbulent Flow: Chaotic water movement with high kinetic energy which allows for fast
       sediment erosion and sediment high carrying capacity.

Underfit: A small water flow eroding a sub-channel within a large currently dry stream channel.

Vegetation Encroachment: Abnormal vegetative growth which impedes the natural flow of a
       water course.

Volume of Flow: A measure of the quantitu of water moving per unit of time.

Water-monitoring Program: A sampling of water at designated locations and times to
       characterize how its qualitites and quantities change over space and time.

Watershed: An area contained within a drainage divide above a specified point on a stream.
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                              Executive Summary
Purpose

       This document supports the United States Environmental Protection Agency's (EPA's)
promulgation of a new Western Alkaline Coal Mining Subcategory under existing regulations at
40 CFR part 434 for the Coal Mining industry. The document was developed primarily using
information supplied by a Western Coal Mining Work Group consisting of representatives from
federal and state regulatory agencies and industry.  The purpose of this document is to provide a
summary of the information collected and used by EPA to support promulgation of this
subcategory and to develop the requirements under the final rule.

Western Alkaline Coal Mining Subcategory

       The Western Alkaline Coal Mining Subcategory addresses sedimentation and erosion
control issues that are characteristic to the arid and semiarid coal producing regions of the
western United States. EPA finds that the use of additional or alternative  sediment control best
management practices (BMP) in non-process areas within these regions can be less harmful to
the environment than the impacts resulting the use of sedimentation ponds only to comply with
numeric limits. EPA believes that controlling sediment generation at the source with the
implementation of BMPs will reduce erosion and sedimentation. EPA also believes that the
implementation of appropriate  BMPs in these regions can prevent the formation of unnatural
geomorphic land and stream forms, and will improve water management,  vegetation,  and land
uses.
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       This rulemaking effort adds a Western Alkaline Coal Mining subcategory to 40 CFR part
434 for coal mining operations conducted in arid and semiarid regions in the western United
States. The Western Alkaline Coal Mining Subcategory is applicable to alkaline mine drainage
from non-process areas, brushing and grubbing areas, topsoil stockpiling areas, and regraded
areas at western coal mining operations.  "Western coal mining operation" is defined as a surface
or underground coal mining operation located in the interior western United States, west of the
100th meridian west longitude, in an arid or semiarid environment with an average annual
precipitation of 26.0 inches or less. "Alkaline mine drainage is defined in the existing
regulations as "mine drainage which, before any treatment, has a pH equal to or greater than 6.0
and total iron concentration of less than 10 mg/L." The regulation applies to the following areas:
       •       "Non-process area" is the  surface area of a coal mine which has been returned to
              required contour and on which revegetation (specifically, seeding or planting)
              work has commenced.
       •       "Brushing and grubbing area" is the area where woody plant materials that would
              interfere with soil salvage operations have been removed or incorporated into the
              soil resource that is being  salvaged.
       •       "Topsoil stockpiling area" is the area outside the mined-out area where soil is
              temporarily stored for use in reclamation, including containment berms.
       •       "Regraded area" is  the surface area of a coal mine which has been returned to
              required contour.

Presumptive Rulemaking

       The Western Alkaline Coal Mining Subcategory was developed using a presumptive
rulemaking effort, implementing recommendations of EPA's Effluent Guidelines Task Force for
streamlining the regulations development process and expediting promulgation of effluent
limitations guidelines (May 28, 1998, 63  FR 29203). Under these recommendations, this
rulemaking effort relies on stakeholder support for various stages of information gathering;
utilizes existing information; focuses on an industry segment for which controls have been
identified that would result in environmental improvements; and is based on early presumptions

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regarding effective control technologies and key pollutant parameters.  Development of this
subcategory relies on existing technical and economic information compiled from demonstrated
successful state approaches, federal regulatory requirements, and regulated community
partnerships.
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Section 1.0      Background

1.1    Legal Authority

       EPA is promulgating the Western Alkaline Coal Mining Subcategory under the authority
of Sections 301, 304, 306, 307, 308, and 501 of the Federal Water Pollution Control Act (Clean
Water Act; CWA). EPA is promulgating this Subcategory also under Section 304(m) of the
Clean Water Act which requires EPA to publish a biennial Effluent Guidelines Plan, set a
schedule for review and revision of existing regulations and identify categories of dischargers to
be covered by new regulations.

       EPA's legal authority to promulgate BMP regulations is found in Section 304(e),  Section
307(b) and (c), Section  308(a), Section 402(a)(l)(B), Section 402(a)(2) and Section 501(a) of the
Clean Water Act, 33 U.S.C. §  1251, et. seq. EPA's legal authority also relies on 40 CFR part
122.44(k).  This BMP regulation is consistent with the Pollution Prevention Act of 1990, 42
U.S.C. § 13101, et. seq.

       This Subcategory is being promulgated in response to the consent decree in NRDC et. al.
v. Browner (D.D.C. Civ. No. 89-2980, January 31, 1992, as modified) which commits EPA to
schedules for proposing and taking final action on effluent limitations guidelines. The consent
decree publication date  for final revised effluent limitations guidelines for the coal mining
industry was published  on August 31, 2000 at 65 FR 3008.

1.2    Regulatory History

       The coal mining industry in the United States has a history covering over two centurie.
During the last thirty years, the proliferation of federal environmental laws has altered the coal
mining industry considerably (Figure la), and environmental impact considerations are now

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commonly woven into most regulatory and industry decision-making. Laws such as the Surface
Mining Control and Reclamation Act (SMCRA) and the Clean Water Act (CWA) reflect a
strong consideration for preservation of resources and protection of fragile and life-supporting
ecosystems.
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Figure la:      Time line of Selected Events Affecting the Coal Mining Industry (modified
                   from EIA, 1995)
                                            Mechanical stokers introduced

                                   Coal-mining machines brought into use

                           United Mine Workers of America formed (1890)

                              Machine developed to undercut coalbeds

             5,000-kilowatt steam turbine introduced to generate electricity
                   Coal mined with steam-powered stripping shovel
                 Short-flame or "permissible" explosives developed
                   Pulverized coal-firing in electric powerplants
                   Mechanical coal-loading machine introduced
      Dragline excavators built especially for surface coal mining
                              1880
                           1890
                                                                                       World War I, increased demand for coal
                                                        1930
                Walking dragline excavators developed

                    Auger surface mining introduced
        1940
 Continuous underground mining systems developed

    Roof bolting introduced in underground mines^


   Longwall mining with powered roof supports
   1950
1960
                                      All-time high employment of 179,679
                                       anthracite miners (1914)
                                  Anthracite production peak of 99.6 million tons (1917)

                                 Federal Mineral Leasing Act of 1920

                               All-time high employment of 704,793
                                 bituminous coal and lignite miners (1923)
        World War II: Coal production increase for the war effort
         and the postwar Marshall Plan
    Railroads converting from coal to diesel fuel

                             /
Unit coal trains introduced by railroads
          Final guidelines promulgated
                at40CFRpart434
Revised effluent limitations guidelines
  promulgated at 40CFR part 434 .
                                         1970
                                      1980
                                  1990
                Federal Clean Water Act of 1972
                Federal Coal Mine Health and Safety Ad of 1969
                Federal Clean Air Act of 1970
                Federal Water Pollution Control Act of 1972
                Arab Oil Embargo; coal production and prices rise
                Federal Coal Leasing Amendments Act of 1976
                Federal Surface Mine Control and Reclamation Act of 1977
                Federal Clean Water Act Amendments of 1977
               >
         Federal Clean Air Act Amendments of 1990
       I Coal Production in excess of 1 billion tons
       '-Federal Energy Policy Act of 1992
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This section presents a summary of SMCRA and CWA regulations affecting the coal mining
industry and, in particular, sedimentation requirements in the arid and semiarid western coal
mining region.  This section also describes selected state programs that deal successfully with
sedimentation issues of coal mines in arid and semiarid regions.

1.2.1  Clean  Water Act

       The Clean Water Act of 1972 and the Clean Water Act Amendments of 1977 established
a comprehensive program to "restore and maintain the chemical, physical, and biological
integrity of the Nation's waters."  To implement the program, EPA was charged with issuing
effluent limitation guidelines standards, pretreatment standards, and new source performance
standards (NSPS) for industrial discharges. These regulations were to be based principally on
the degree of effluent reduction attainable through the application of control technologies.

       On October 17, 1975 (40 FR 48830), EPA proposed regulations adding part 434 to Title
40 of the Code of Federal Regulations.  These regulations, with subsequent amendments,
established effluent limitations guidelines for coal mine operations based on the use of the "best
practicable control technology currently available" (BPT) for existing sources in the coal mining
point source category. These regulations were followed on April 26, 1977 (42 FR 21380) by
final BPT effluent limitations guidelines for the coal mining point source category. BPT
guidelines were established for total suspended solids, pH, total iron, and/or total manganese for
three subcategories: Acid Mine Drainage, Alkaline Mine Drainage, and Coal Preparation Plants
and Associated Areas. At that time the guidelines did not apply to discharges from non-process
areas, nor did TSS limitations apply to any discharges from coal mines located in Colorado,
Montana, North Dakota, South Dakota, Utah, and Wyoming.

       On October 9,  1985 (50 FR 41296), EPA promulgated the revised effluent limitations
guidelines and standards that are in effect to date under 40 CFR part 434.  Currently, there are
four subcategories: Coal Preparation Plants and Coal Preparation Plant Associated Areas, Acid
or Ferruginous Mine Drainage, Alkaline Mine Drainage, and Post-Mining Areas, along with a

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subpart for Miscellaneous Provisions with BPT, BAT, and NSPS limitations for TSS, pH, total
iron, total manganese, and settleable solids (SS). Specifically, effluent limitations for discharges
from non-process areas include SS and pH at 0.5 ml/L and 6 to 9 standard units, respectively.

       On October 18, 1997, Vice President Gore called for a renewed effort to restore and
protect water quality.  EPA and other federal agencies were directed to develop a Clean Water
Action Plan that addressed three major goals: (1) enhanced protection from public health threats
caused by water pollution; (2) more effective control of polluted runoff; and (3) promotion of
water quality protection on a watershed basis.  The Clean Water Action Plan was to be based on
three principles:

       •       Develop cooperative approaches that promote coordination and reduce
              duplication among federal, state, and local agencies and tribal governments
              wherever possible;

       •       Maximize the participation of community groups and the public, placing
              particular emphasis on ensuring community and public access to information
              about water quality issues; and

       •       Emphasize innovative approaches to pollution control, including incentives,
              market-based mechanisms, and cooperative partnerships with landowners and
              other private parties.

       Based on the efforts of interagency work groups and comments from the public, EPA and
other federal  agencies developed the final Clean Water Action Plan that was submitted on
February 14,  1998. One of several Key Actions specifically identified to implement the goals of
the Clean Water Action Plan was EPA's project to re-examine 40 CFR part 434 to better address
coal mining in arid western areas.
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       On May 28, 1998 (63 FR 29203), EPA announced plans for developing new and revised
effluent limitations guidelines for selected industrial categories, and described revisions to its
regulations development process. Included in this program was the re-examination of 40 CFR
part 434. The program and schedule announced in May 1998 were established in response to a
consent decree resulting from legal action taken by the Natural Resources Defense Council
(D.D.C. No. 89-2980, January 31, 1992).

1.2.2  Surface Mining Control and Reclamation Act (SMCRA)

1.2.2.1 SMCRA History

       In 1977, Congress enacted the Surface Mining Control and Reclamation Act, 30 U.S.C.
1201 etseq, to address the environmental problems associated with coal mining.  The previous
lack of uniformity among state surface mining programs and the increase in unreclaimed land
and associated pollution of water and other resources forced the federal regulation of surface
coal mining activities.  SMCRA established a coordinated effort between the states and the
federal government to prevent the abuses that had characterized surface and underground coal
mining in the past, and created two major programs:

       •      An environmental protection program to establish standards and procedures for
              approving permits and inspecting active coal mining and reclamation operations
              both surface and underground; and

       •      A reclamation program for abandoned mine lands,  funded by fees on coal
              production, to reclaim land and water resources adversely affected by pre-1977
              coal mining.

       SMCRA created the Office of Surface Mining Reclamation and Enforcement within the
Department of Interior, and charged it with the responsibility  of preparing regulations and
providing financial and technical assistance to the states to carry out regulatory activities. Title

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V of the statute gives OSMRE broad authority to regulate specific management practices before,
during, and after mining operations.  OSMRE has promulgated comprehensive regulations to
control both surface coal mining and the surface effects of underground coal mining (30 CFR
part 700 etseq). Implementation of these requirements has led to significant improvements in
mining practices and serves to control the pollution of water and other resources.

1.2.2.2 SMCRA Requirements

       SMCRA requirements set general performance standards for environmental protection
for any permit to conduct surface coal mining and reclamation operations.  The performance
standards that are particularly applicable to the final Western Alkaline Coal Mining Subcategory
are summarized as follows:

       •       Restore the land affected to a condition capable of supporting the uses which it
              was capable of supporting prior to mining, or higher or better uses;

       •       Stabilize and protect all surface areas affected by the mining and reclamation
              operation to effectively control erosion;

       •       Create, if authorized in the approved mining and reclamation plan and permit,
              permanent impoundments of water on mining sites as part of reclamation
              activities only when it is adequately demonstrated that: such water
              impoundments will not result in the diminution of the quality or quantity of water
              utilized by adjacent or surrounding landowners for agricultural, industrial
              recreational, or domestic uses;

       •       Minimize disturbance to the hydrologic balance at the mine-site and in associated
              offsite areas and to the quality and quantity of water in surface and ground water
              systems both during and after surface coal mining operations and during
              reclamation;

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       •      Establish an effective, permanent vegetative cover at least equal in extent of cover
              to natural vegetation or as necessary to achieve the approved postmining land use;

       •      In those areas or regions where the annual average precipitation is twenty-six
              inches or less, assume the responsibility for successful revegetation for a period
              of ten full years;

       •      Protect offsite areas from slides or damage occurring during the surface coal
              mining and reclamation operations;

       •      Meet other criteria as necessary to achieve reclamation in accordance with
              SMCRA, taking into consideration the physical, climatological, and other
              characteristics of the site; and

       •      To the extent possible using the best technology currently  available, minimize
              disturbances and adverse impacts of the operation on fish,  wildlife, and related
              environmental values, and achieve enhancement of such resources where
              practicable.

       Each SMCRA permit includes detailed pre-mining baseline conditions, a prediction of
the probable hydrologic consequences of mining on the hydrologic balance, a hydrologic
reclamation plan designed to minimize predicted consequences, and a detailed monitoring plan
to verify and characterize hydrologic consequences. However, meeting numeric effluent
limitations under the CWA has taken precedence over SMCRA's requirement to minimize, to the
extent possible, impacts to the  hydrologic balance.  This precedent has, at times, resulted in
adverse environmental effects and impacts to the hydrologic balance.

       Under SMCRA, coal mine operators are required to collect a minimum of one year of
pre-mining or baseline surface and ground water monitoring data before submitting a coal

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mining and reclamation permit application.  The baseline information is used to prepare
site-specific erosion and sedimentation plans capable of minimizing adverse impacts within the
permit area and adjacent lands. It is also used to perform a Probable Hydrologic Consequences
(PHC) evaluation to identify regional hydrologic impacts associated with the coal mining and
reclamation operation. When potential adverse impacts are identified, appropriate protection,
mitigation, and rehabilitation plans are developed and included in mining and reclamation permit
requirements.  The PHC and the accompanying plans are reviewed and approved by regulatory
authorities before mining and reclamation activities are initiated.

       Coal mine operators are required to submit bonds covering the costs of reclaiming and
restoring disturbed areas to acceptable environmental conditions in the event of default and
failure to discharge this obligation. Mid-term mining and reclamation permit reviews and
renewals assess the adequacy of the site's erosion and sedimentation control, treatment,
mitigation, and rehabilitation.

       Coal mine operators are required to conduct and submit the results of surface and ground
water monitoring under SMCRA and CWA NPDES permits on  a periodic basis.  Monitoring
results are used to assess the adequacy of erosion and sedimentation control measures.  At the
conclusion of mining and reclamation activities, surface water monitoring information is used to
summarize the effectiveness of erosion and sedimentation control in restoring the hydrologic
system.  This evaluation is part of a Cumulative Hydrologic Impact Assessment (CHIA) required
when the coal mining company applies for final reclamation liability and bond release.
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1.2.2.3 Flannery Decision

       SMCRA requirements include performance standards for surface mining operations to be
conducted in a manner that minimizes disturbance to the prevailing hydrologic balance.
SMCRA specifies sediment control performance standards for
       "conducting surface coal mining operations so as to prevent, to the extent possible using
       best technology currently available (BTCA), additional contributions of suspended solids
       to stream flow, or to runoff outside the permit area. In no event shall contributions be in
       excess of requirements set by applicable state or federal law (30 U.S.C. §
       OSMRE implemented the statutory hydrologic balance protection performance standard
by requiring, with some exceptions, that all surface drainage from disturbed areas pass through
sedimentation ponds before leaving the permit area (30 CFR part 816.42(a)(l) and 817.42(a)(l)).
       In 1981 (46 FR 34784), OSMRE proposed revisions to the siltation structure regulations
that incorporated the flexibility to allow the use of alternative sediment control measures in lieu
of sedimentation ponds.  OSMRE received extensive comments on the question of whether
sedimentation ponds and similar siltation structures constitute BTCA in all circumstances. The
final rule promulgated in 1983 deleted the provision that allowed alternative sediment control
measures, and retained the prior requirement that all drainage from disturbed areas (except for
small areas) pass through a siltation structure before leaving the permit area.

       The coal industry challenged the blanket requirement in OSMRE's rules that all surface
drainage from disturbed  areas pass through a siltation structure before leaving the permit area,
and in 1985 the United States District Court for the District of Columbia remanded the rules as
arbitrary and capricious.  Judge Thomas Flannery found that OSMRE failed to adequately
explain why siltation ponds were considered BTCA (In Re Permanent  Surface Mining
Regulation Litigation, 620 F. Supp. 1519, 1565-68 D.D.D. 1985).  The decision was supported
by record evidence that siltation structures are not always BTCA and OSMRE's recognition that
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these structures may pose negative impacts. In 1986 (51 FR 419252), OSMRE suspended the
rule and explained that the regulatory authority will determine on a case-by-case basis what
constitutes BTCA.

       In 1990 (55 FR 47430), OSMRE proposed revisions to the federal rules to allow the use
of alternative sediment control measures in lieu of sedimentation ponds in the arid and semi-arid
west. OSMRE never took further action on the proposal. Currently, it is the responsibility of the
regulatory authority to determine, on a case-by-case basis, what constitutes BTCA for
preventing, to the extent possible, additional contributions of suspended solids to stream flow or
runoff outside the permit area.

1.2.3  State Regulatory Guidelines for Sediment Control

       The states of Wyoming and New Mexico, under federally approved SMCRA primacy
programs, have developed regulations to allow the use of sediment control BMPs  to prevent
environmental problems associated with preferential use of sedimentation ponds in the arid and
semiarid west. The regulations or guidelines have been reviewed and approved by OSMRE.
Utah is developing alternate sediment control guidelines that have not been published to date.
Although the requirements for these programs vary  somewhat between states, the  intent is to
provide greater protection to the hydrologically sensitive watersheds in this region.

1.2.3.1 Wyoming Coal Rules and Regulations, Chapter IV

       Under Wyoming's Coal Rules and Regulations, implemented by the Land Quality
Division (LQD) of Wyoming's Department of Environmental Quality (WY DEQ), exemptions to
the use of sedimentation ponds may be granted where, by the use of alternative sediment control
measures, the drainage will meet effluent limitation standards or will not degrade  receiving
waters (Chapter IV, Section 2(f)(i)). Chapter IV of these regulations also sets environmental
protection performance standards that require coal mine operators to implement best
management practices including contemporaneous backfilling and grading, reclamation to

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approximate original contour, and erosion reduction measurements.  Under Chapter IV, Section
2(e)(i), discharges should be controlled as necessary to reduce erosion, to prevent deepening or
enlargement of stream channels, and to minimize disturbance of the hydrologic balance.

       Chapter IV of these regulations also states that appropriate sediment control measures
(e.g., stabilizing, diverting, treating or otherwise controlling runoff) shall be designed,
constructed, and maintained using BTCA to prevent additional contributions of sediment to
streams or to runoff outside the affected area.  Chapter IV requires that a surface
water-monitoring program be used to demonstrate that the quality and quantity of runoff from
affected lands will minimize disturbance to the hydrologic balance. Wyoming's Coal Rules and
Regulations, Chapter IV are provided as Appendix A  to this document.

1.2.3.2 Wyoming Coal Rules and Regulations,  Guideline No. 15

       Wyoming's LQD developed Guideline No. 15  for Alternative Sediment Control Measures
(ASCMs) or best management practices that may be used in addition to or in place of
sedimentation ponds. The guideline supports requirements of the Wyoming DEQ/LQD Coal
Rules and Regulations, Chapter IV and provides guidance for determining best technology
currently available for designing, constructing, implementing, and maintaining ASCM, and for
determining the contents of an ASCM proposal.

       Guideline No. 15 identifies specific sediment control measures that may be used in
addition to or in place of sedimentation ponds and supports the use of alternative sediment
control measures as  an option under Wyoming's Coal  Rules and Regulations.  Guideline No. 15
recommends: determination of BTCA on a case-by-case basis, prevention of soil detachment and
erosion, retention of sediment as close as possible to its point of origin, and implementation of
sediment traps only  as a second line of defense. Wyoming's Guideline No.  15 are provided in
Appendix B of this document.  A summary of the guideline is presented below.

Determination of Best Technology Currently Available

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       Guideline No. 15 recognizes that design methods, construction techniques, maintenance
practices, and monitoring all contribute to a system that can be considered BTCA. Additionally,
the guideline recognizes that BTCA must be determined on a case-by-case basis. Factors
considered in BTCA determinations include the size and type of disturbance and the length of
time the ASCM will be in place.  Determination also should be based on how effective the
ASCM is at preventing soil detachment and erosion, and how effective the ASCM is on retaining
sediment as close as possible to its point of origin.

Design of ASCM (for areas 30 acres and larger)
       For sites larger than 30 acres, the mine operator is required to submit a general
description of the area to be controlled by  ASCM and the types and duration of expected
disturbance, including the distance to and type of nearest receiving stream. A description of the
sediment control plan, including justification for ASCM design parameter values and date of
construction or implementation, is to be included. The use of site-specific data is encouraged.
Topographic maps detailing the use of ASCM in relation to the mining and reclamation sequence
is required.  Annual reports detailing ASCM modifications are required if adjustments are made
to the approved permit system. The guideline recommends that the ASCM design be based on
predicted sediment loads or yields from the area disturbed compared to predicted or measured
native sediment yields. State-of-the-art computer watershed models are recommended for use as
a design tool.

Design of ASCM (for areas less than 30 acres)
       Sediment control design requirements for small disturbed areas are concerned primarily
with establishing use and safety criteria commensurate with the intended use and life of the
structures.  For these areas, the operator is required to  submit the sedimentation control plan and
justification, a plan view location, and  a general description of the type of ASCM structures.
The sediment control plan  should implement sediment trapping structures to pass or detain
runoff from storm events such as toe ditches and rock check dams.  ASCM proposals for small
areas also should present the inspection and maintenance programs the operator will use to
regularly evaluate the stability and effectiveness  of each ASCM.  The program recognizes that

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the effectiveness and capabilities of many ASCM have been documented and need not be
reiterated for small area application.

Implementation Priorities (for post-mining surfaces)
       Guideline No. 15 highly recommends ASCM design approaches that stabilize land forms
to minimize sediment yield. Short-term slope erosion  control methods are recommended, such
as regrading, mulching, and rapid establishment of vegetation. The guideline also recommends
in-channel sediment retention and removal of trapped sediment.  Sedimentation ponds should be
implemented when maintenance of ASCMs is a chronic problem.

ASCM Performance Monitoring
       Monitoring of small ephemeral receiving streams should include visual inspection
following each runoff event, and repeat photographs taken at least annually  and after major
runoff events. Monitoring of large ephemeral receiving streams should include visual
inspection, repeat photographs, repeat surveys, and upstream and downstream sediment yield
monitoring stations. Guideline No. 15 recognizes that each type of ASCM has construction and
maintenance guidelines that are specified in most handbooks on  sediment control.  The operator
is required to:
       "report, repair and log any significant damage to an ASCM as soon as possible after the
       damage occurs.  The operator should inspect the ASCM at the beginning and at the end
       of each runoff season, and after each runoff event. An inspection and maintenance log
       should be kept to document the condition of each ASCM at the time of each inspection.
       The log should describe any damage, required maintenance, and the date repairs were
       made."
1.2.3.3 New Mexico's ASC Windows Program

       New Mexico's Mining and Minerals Division (MMD) enforces the state's federally
approved SMCRA primacy program. BMP regulations for mining and reclamation operations in

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New Mexico may be found under 19 NMAC 8.2 Subpart 20 Section 2009 which addresses
requirements for minimizing changes to the prevailing hydrologic balance in both the permit and
adjacent areas.  Section 2009 of Subpart 20 is included as Appendix C of this document.

       Under New Mexico's program at Section 2009.E (commonly referred to as the "ASC
Windows Program"), requirements to pass all disturbed area runoff through a sedimentation
pond or series of sedimentation ponds can be waived.  If the operator chooses not to operate
under the provisions set forth at 2009.E, then all runoff must be passed through sedimentation
ponds before leaving the permit area. To waive sedimentation pond requirements, the operator
must demonstrate that erosion is sufficiently controlled and that the quality of area runoff is as
good as or better than that of water entering the permit area. The regulations recognize that
certain methods are capable of containing or treating all  surface flow from the disturbed areas
and shall be used in preference to the use of sedimentation ponds or water treatment facilities.
These practices to control sediment and minimize water  pollution include, but are not limited to:

       •      Stabilizing disturbed areas through land shaping, berming, contour furrowing, or
              regrading to final contour;
       •      Planting temporary vegetation that germinates and grows quickly;
       •      Regulating channel velocity of water and diverting runoff;
       •      Lining drainage channels with rock or revegetation; and
       •      Mulching disturbed areas.

       The operator's plan for alternative sediment control must demonstrate that there will be
no increase in the sediment load to receiving streams.  The plan also must demonstrate that there
will be no resulting environmental harm or degredation,  threat to public health or safety, or
resulting pollution or other diminishment of existing streams and drainages that could cause
imminent environmental harm to fish and wildlife habitats. The operator is responsible for
taking baseline and ongoing surface and ground water monitoring samples. The MMD may
require additional tests and analyses as deemed necessary by baseline and ongoing monitoring
results.  Surface water monitoring continues until final bond release.
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       Several mine operations in New Mexico have applied for and received reclamation
liability bond releases for lands where sediment control BMP plans were implemented (e.g.,
Carbon II mine and De-Na-Zin mine).  These sites demonstrated that there was no contribution
of additional suspended solids to the hydrologic regime of the area and that runoff from regraded
areas was as good as or better than runoff from undisturbed areas (WCMWG, 1999a).
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Section 2.0      Industry Characterization

       This section describes the coal mining industry in the arid and semiarid areas west of the
100th meridian and details the environmental factors that make mining and reclamation activities
in these areas different than coal mining in the rest of the United States.

2.1    Location and Production

       The United States is divided into three major coal producing regions: Appalachian,
Interior, and Western (Figure 2a). Mines affected by the proposed Western Alkaline Coal
Mining Subcategory are within the Western Coal Region and are defined as mines that:

•      Are west of the 100th meridian west longitude,
•      Are located in arid or semiarid areas with an average annual precipitation of 26 inches or
       less, and
•      Produce alkaline mine drainage.

       The Western Coal Region contains extensive deposits of low-sulfur coal (Figure 2a).
Most of the coal mined in the Western Region is sub-bituminous, i.e., has a lower Btu content
(8,3000 - 13,000)  than eastern bituminous coal (>13,000). Western coal seams lie at various
depths below the surface and vary in thickness from a few inches to over 70 feet (Energy
Information Administration, 1995).  The economic ability to mine the coal seams varies
throughout the region and is dependent on coal quality, seam thickness, depth of overburden,
geologic characteristics, and market factors.  In areas such as the Southern Powder River Basin
of Wyoming, thick coal seams and shallow overburden enable  the extraction of large volumes of
coal at relatively low cost.  The low-sulfur content, in demand since the passage of the Clean
Air Act, and the potentially low cost of extraction mean that coal resources in the Western Coal
Region represent a highly competitive fuel in the power generation market. As the fuel market
has changed, coal  production within the Western Region has increased, now being nearly equal
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to the formerly dominant Appalachian Region.  The United States produced 1.1 billion short tons
of coal in 1997, with the Appalachian Region producing 469 million short tons, the Interior
Region producing 172 million short tons, and the Western Region producing 451 million short
tons (Table 2a).
Figure 2a:    Coal Producing Areas (modified from USGS, 1996)
                                       100* Meridian
           Lignite

           Subbituminous Coal
           Medium and High-Volatite
           Bituminous Coal
           Low-Vdable Bituminous Coal
           Anthracite and SemHnlhracite
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Table 2a:
United States Coal Production by Region (short tons; Energy Information
Administration, 1997)

Appalachian Region
Interior Region
Western Region
Total
1970
427,600,000
149,900,000
35,100,000
612,600,000
19971
468,778,000
171,863,000
451,291,000
1,089,932,000
              The total does not equal the sum of components due to independent rounding.

       While domestic coal production has increased since 1970, fewer operating mines exist
today, representing higher mine production.  In 1997, the number of mines producing coal was
less than half the number producing coal  in 1988 (e.g., 3,860 mines in 1988 compared to 1,828
mines in 1997), and in the Western Region the number of mines fell from 114 to 77 in the same
time period (Energy Information Administration, 1997).  According to the Energy Information
Administration, in 1988, the Western Region produced approximately 308 million short tons of
coal, 68 percent of the 451 million short tons of coal the Western Region produced in 1997
(Energy Information Administration, 1997).

       Of the 77 mines operating in the Western Region, EPA has identified 47 surface mines
that potentially will be affected by the Western Alkaline  Coal Mining Subcategory. One of these
mines, however, currently is in the final reclamation phase and most likely will be unaffected.
The 47 mines produce approximately 497 million tons of coal annually, affect 192,411 acres of
land, and are located in Arizona (2 mine sites), Colorado (5 mine sites), Montana (6 mine sites),
New Mexico (6 mine sites), and Wyoming (28 mine sites). These sites are listed along with
operation and production statistics in Table 2b.
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Development Document - Western Alkaline Coal Mining Sub category
Table 2b:    Operation and Production Statistic of Potentially Affected Coal Mines in the
             Arid and Semiarid Coal Producing Region (modified from Western Coal
             Mining Work Group, 1999b).
STATE
AZ
AZ
CO
CO
CO
CO
CO
MT
MT
MT
MT
MT
MT
NM
NM
NM
NM
NM
NM
WY
WY
WY
WY
WY
WY
WY
MINING
SINCE1
Jan-70
May-74
Feb-77
Pending
-
Jan-64
Jan-77
Jul-94
Jan-69
Feb-71
Jan-68
Oct-58
Dec-80
Aug-86
Jan-84
Jan-64
Jan-63
Jan-73
Feb-89
Jan-83
-
Nov-72
-
-
Aug-76
Jan-81
ANNUAL
PRODUCTION
(1,000s of tons)2
4,634
7,090
5,544
0
-
1,350
2,002
7,051
4,335
117,000
9,146
330
9,015
2,375
4,900
6,607
8,200
4,072
1,259
13,559
0
22,800
80
1,857
50,000
18,000
AVG.
S/TON
(STATE*3
$25.17
$25.17
$ 18.46
$ 25.00
$ 18.46
$ 18.46
$ 18.46
$ 9.84
$ 9.84
$ 9.84
$ 9.84
$10.10
$ 9.84
$21.83
$ 21.83
$ 21.83
$ 26.00
$21.83

$ 6.00
n.a.
$ 6.00
$ 6.00
$ 6.00
$ 6.00
$ 4.00
YEARLY
VALUE
(l,000s)4
$ 116,638
$ 178,455
$ 102,342
-
-
$ 24,921
$ 36,957
$ 69,382
$ 42,656
1,151,280
$ 89,997
$ 3,333
$ 88,708
$ 51,846
$ 106,967
$ 144,231
$ 213,200
$ 88,892
$ 27,484
$ 81,354
-
$ 136,800
$ 480
$ 11,142
$ 300,000
$ 72,000
INDIAN
LANDS
Navajo &
Hopi
Navajo &
Hopi
No
No
No
No
No
No
No
No
No
No
No
No
No
Navajo
Navajo
No
No
No
No
No
No
No
No
No
AFFECTED
ACRES5
6,255
13,604
2,782
0
-
-
5,116
-
3,437
6,093
-
430
2,251
1,799
3,800
13,000
7,188
4,969
-
3,059
249
11,621
1,969
14,860
13,017
3,789
MINE
LIFE
(YEARS)
6
12
16
15
-
-
16
-
6
28
-
20
17
18
30
12
18
18
-
18
-
-
-
-
24
-
PROJECTED
DISTURBANCE
(ACRES)
7,236
16,351
3,810
1,161
-
-
6,300
-
500
8,579
-
875
4,485
2,085
11,300
4,546
11,000
6,216
-
5,172
-
-
-
-
12,172
-
2-4
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STATE
WY
WY
WY
WY
WY
WY
WY
WY
WY
WY
WY
WY
WY
WY
WY
WY
WY
WY
WY
WY
WY
Total
MINING
SINCE1
Jan-78
Nov-82
-
Dec -76
Oct-58
-
Jan-78
Mar-976
Aug-76
May-73
Jan-50
Jan-74
Jan-83
Sep-89
Nov-77
Nov-85
-
Jan-73
Oct-76
-
Jan-22
-
ANNUAL
PRODUCTION
(1,000s of tons)2
19,946
14,681
5,805
13,324
4,200
2,986
17,921
1,005
27,113
6,231
4,402
600
34,965
5,000
10,706
26,640
-
500
769
-
3,242
496,608
AVG.
S/TON
(STATE*3
$ 6.00
$ 6.00
$ 6.00
$ 6.00
$ 9.00
$ 6.00
$ 6.00
$ 6.00
$ 6.00
$ 6.00
$ 6.00
$ 6.00
$ 6.00
$ 6.00
$ 6.00
$ 6.00
$ 6.00
$ 6.00
$ 6.00
$ 6.00
$ 6.00
$ -
YEARLY
VALUE
(1,000s'4
$ 119,676
$ 88,086
$ 34,830
$ 79,944
$ 37,800
$ 17,916
$ 107,526
$ 6,030
$ 162,678
$ 37,386
$ 26,412
$ 3,600
$ 209,790
$ 30,000
$ 64,236
$ 159,840
-
$ 3,000
$ 4,614
-
$ 19,452
$ 4,235,243
INDIAN
LANDS
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
-
AFFECTED
ACRES5
9,686
2,374
8,310
4,576
4,590
3,124
5,706
145
5,624
7,792
10,622
5,551
2,687
4,016
8,316
7,041
-
3,523
1,011
-
959
192,411
MINE
LIFE
(YEARS)
-
14
-
14
9
-
-
28
15
25
26
12
-
-
-
-
-
12
-
-
32
-
PROJECTED
DISTURBANCE
(ACRES)
-
6,631
-
7,275
2,000
-
-
1,886
8,207
10,429
4,960
5,765
-
-
-
-
-
3,576
-
-
2,129
141,521
Month and year from DOE database.
      or      repore  o
of Energy Web site (cite).
3
        values are
                 £ (cite;.
                 ; of a ton of coal sold by all reporting mines in the state in which the mine is located. Where state
        values are unavailable, the Western Region average value was used.
4The Annual Production figure multiplied by the average price/ton.
5The total number of all acres disturbed to date by the mining operation.  Acres disturbed for the extraction of coal
        are contemporaneously reclaimed (i.e., within four spoil ridges or 180 days whichever comes first), unless
        a variance is approved by the regulatory authority.
6The date of last permit transfer. Mining commenced prior to this date.
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2.2    Environmental Conditions

       Coal mining operations potentially affected by the Western Alkaline Coal Mining
Subcategory operate under environmental conditions that are noticeably different from those in
other regions of the United States. Background surface conditions are defined in this
environment by the direct response of the geologic and soil-forming environment to the arid
climate.  Climatic, geologic, soil-forming, and topographic factors directly influence distribution
and composition of vegetation in the arid and semiarid west. Western arid and semiarid areas
may contain naturally unstable areas with highly eroded landscapes that are created by flash
flooding which transports large volumes of sediment.  Water resources are severely limited and
highly valued. Common conditions occurring throughout the arid and semiarid western
coal-bearing region are summarized categorically below.

2.2.1  Temperature

       Temperatures in the arid and semiarid western United States fluctuate over wide daily
and seasonal ranges.  A daily range of 30°F to 50°F (-1°C to 10°C) is common, while the
seasonal temperature ranges from -40°F to 115°F (-40°C to 46°C). Large diurnal fluctuations
contribute to the physical weathering of surface materials, which increases the amount of small
sediment particles available for transport by runoff generated during significant storm events.
Intense wind  storms generated by frontal weather systems and regional weather patterns in this
region also can transport substantial amounts of sediment.

2.2.2  Precipitation

       Arid and semiarid locations average 26 inches or less of annual precipitation, with
roughly equal parts occurring as snowfall and rainfall.  Average annual precipitation received in
western states containing arid and semiarid areas is presented in Table 2c.

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Table 2c:     Average Annual Precipitation (inches) in Arid and Semiarid Coal States
              (from National Oceanic and Atmospheric Administration, 1998)
State
Arizona
Colorado
Montana
New Mexico
Wyoming
Long-Term Average Annual Precipitation (inches)
1899 - 1998
12.77
15.90
15.36
13.45
13.16
       Much of the rainfall in the arid and semiarid western United States is received during
localized, high-intensity, short-duration thunderstorms, and research has indicated that relatively
few storms may produce the greatest amount of erosion (Peterson, 1995). Western precipitation
storms producing runoff are typically:
•      Cellular in nature - localized intensity and relatively limited in areal extent;
•      Of short duration; and
•      Characterized by large raindrops with high kinetic energy.

       Studies of precipitation typically received in arid areas indicate that the dominant
precipitation events that produce runoff generally have between 1-hour and 3-hour duration
peaks. For arid lands, up to 80 percent of the total 24-hour rainfall occurs within 3-hours
(Hromadka, 1996).  These storm events result in short-duration, sediment-rich flash flood runoff.
Hjemfelt (1986) reported that only three to four percent of storm events accounted for 50 percent
of long term sediment yields.

       Evapotranspiration normally exceeds precipitation since solar energy is high in western
arid and semiarid areas and humidity is characteristically very low. Water infiltration and
retention in the soil is frequently limited, creating a net negative water balance.  The negative
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water balance results in severe soil moisture deficits, extremely limited surface water resources,
and poor plant growth and cover.

2.2.3  Erosion Prone Soils

       Certain soils in arid and semiarid areas may be prone to erosion and weathering.  On
steep slopes, soil-forming materials frequently erode faster than they are formed. Where erosion
rates are lower and soil is capable of forming, the soil typically is poorly developed with low
organic matter and plant nutrient content. Soil moisture contents are characteristically low
because of limited precipitation, low soil infiltration rates, and nominal amounts of organic
matter.

       A source of erosion is the energy created by "raindrop splash." Raindrops contain
enough energy to mobilize sediment and transport it down slope. In a sediment rich
environment, overland flow reaches its suspended solids carrying capacity after a short distance
or period of time. When  overland flow reaches dynamic sediment loading equilibrium, entrained
particles are dropped and new ones are picked up until the kinetic energy of the flow is changed.
When overland flows decrease in velocity, such as at the base of a concave slope, kinetic energy
decreases, and entrained sediments are released and deposited.  Ephemeral gullies on these lands
carry flow only at times of severe storm or spring snowmelt (Heede,  1975).

2.2.4  Hydrology and Sedimentation

       The western region of the United States is geomorphically young and active with a
weathered topography. The landscape in the arid and semiarid regions is a mixture of mountains,
mesas, plains, buttes, valleys, and canyons, and the effects of active erosion, flash flooding, and
other dynamic geologic processes are pervasive. Flow channels frequently contain multiple
terrace levels. Instability within drainage systems is readily observed with channel head-cutting,
aggradation, bank slumping and actively changing watercourses commonly occurring.
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       Perennial rivers are predominant in this region and most commonly originate in
mountainous areas with significant snow (in areas with average annual precipitation greater than
26 inches per year) or in very large watersheds. Ephemeral drainage systems predominate in
small to medium-sized headwater areas.  These ephemeral drainage systems are composed
primarily of dry washes and arroyos, the  lower ends of such features sometimes being depicted on
USGS topographic maps as intermittent streams. More often than not, drainage features thus
depicted:
       •       Conduct ephemeral surface water flow;
       •       Are mainly composed of sand bed channels;
       •       Have channel banks of unconsolidated alluvial deposits;
       •       Possess a nearly unlimited source of sediment that may be transported by flash
              flooding; and
       •       Commonly contain sediment at concentrations as high as 1 x 106 mg/L during flash
              flood runoff events.

       For an average of 11 to 11 l/2 months a year the washes  and arroyos are dry, normally
flowing only in direct response to precipitation runoff. When rainfall does generate runoff, it is
frequently characterized by high-volume, high-velocity, sediment-laden, and turbulent flows with
tremendous kinetic energy that ceases soon after the precipitation event stops.  For many very
short-duration precipitation events, the runoff water never reaches the main-stem channels
downstream. This turbulent flow pattern establishes a fluvial dynamic equilibrium in arroyos and
washes that is characterized by episodic aggradation and degradation of channel morphologic
characteristics. The sediment is continually transported down-stream, normally at the maximum
level of concentration possible for the kinetic energy available within a given flow.
       Floodplains that develop on arid landscapes are wide and unstable, as the morphology and
position of the main stem channels change with every major precipitation event. The migration of
the channels across the landscape redistributes the sediment, with the primary source  of sediment
the mass wasting of the vertical sides of the arroyo channels. In comparison to the total amount
of sediment involved in erosion, transport, and deposition during runoff from a given storm event,
a relatively small amount of sediment actually leaves the watershed.

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2.2.5 Vegetation

       The response of vegetation to the low amount of precipitation in the arid and semiarid coal
regions is evident. The major vegetation zones in this western environment are desert, grass and
brush lands, and open forests types (e.g., pinyon-juniper and ponderosa pine) characterized by
discontinuous and sparsely distributed grasses, forbs, shrubs, and trees. Species composition
varies from north to south and at various elevations. Slope, aspect, moisture retention, and solar
insulation play a significant role in the distribution of plants within a given area.  Most plants
within the arid and semiarid precipitation zones have adapted their ability to germinate, establish,
and grow to the dry conditions and cycles prevalent throughout the region. With moisture
availability being the primary limiting resource to plant growth, floral adaptations and growth
habits center around a variety of moisture harvesting, conservation, and retention strategies.
Living ground cover is frequently sparse, although cumulative ground cover may be significant
since decomposition tends to be retarded by limited moisture availability.

2.2.6 Watershed Runoff Characteristics

       Ephemeral and intermittent flows in the arid and semiarid western United States are
unique in their flow and duration characteristics. Runoff generated by a single storm event may
last from a few minutes to hours depending upon the size and characteristics of the affected
watershed. Typically, flows last a few hours and, except for a high-water debris line, any
evidence of their passage is gone within 48 hours or less.  Frequently, flows run above ground for
short to moderate distances, and gradually dissipate into the beds of the dry washes and arroyos
they have followed or created.

       While storms in this region typically drop less precipitation than their eastern
counterparts, the intensity is often  greater, and the amount of runoff generated is normally equal
to or greater than that created by an eastern precipitation event of equivalent size.  The increased
runoff occurs because the poorly developed soil and sparse vegetation of western areas have a

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                                    Development Document - Western Alkaline Coal Mining Subcateeorv
greatly reduced capacity to capture and harvest precipitation.  The water that collects and drains
from western precipitation events is nominally impeded and runoff characteristically takes the
form of turbulent, high-velocity, flash floods. Rising stages often start initially as a trickle of
water, followed by a wall of water roaring through the channel a few minutes later.  Multiple
crests may occur as subwatershed runoff is delivered to a main channel.  As the flow recedes,
velocity and volume fall off rapidly and trickle to an end over a period of a few hours.

       Sediment concentration in these turbulent flows normally has a direct relationship to their
kinetic energy.  Sediment is in abundance within the channels where flow occurs and occurs at
concentration levels near or at flow carrying capacity. Sediment concentration frequently varies
over a wide range of concentration levels during a given flow event. Sediment content from a
few thousand to 500,000 mg/L may be expected with values in the 25,000 to 150,000 mg/L range
being common. The variation occurs primarily with changes in flow volume and velocity,
although rising and falling stages may exhibit differing sediment concentrations at similar stage
heights.

2.2.7  Cumulative Effect

       The cumulative effect of the geologic, hydrologic, and climatic conditions unique to this
arid and semiarid region can be summarized as  follows:
       •       Western arid and semiarid areas  are naturally geomorphically unstable;
       •       Landforms frequently exhibit dynamic geomorphologic and erosion processes;
       •       There is virtually an unlimited supply of sediment available within the arroyos and
              washes;
       •       Large volumes of sediment are normally transported by short duration, flooding,
              and turbulent flows;
       •       Particle erosion from a rough steep topography contributes dramatically to the
              natural generation of sediment;
       •       The runoff pattern predominating in ephemeral watersheds is flash flooding; and
       •       The sediment yield in tons per acre per year from these lands is significantly

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Development Document - Western Alkaline Coal Mining Sub category
              higher than from similarly undisturbed vegetation covered lands of the
              mid-western and eastern United States.

       Although water is sparse, the amount of water that physically runs off is significant due to
the nature of the soils and the lack of effective surface cover. It is this runoff that has created the
landscape and variable topography that is prevalent throughout this region. Environmental
conditions limit surface and shallow subsurface water resources and the distribution and
development of aquatic and riparian biologic resources. Direct use of surface-water runoff by
man and wildlife also is limited due to its sporadic availability and poor physical quality. The
limited surface-water resources that do occur within the region have high habitat and use values.
Infiltration of surface runoff to local water tables provides limited, but valuable, useable
ground-water resources.
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                                  Development Document - Western Alkaline Coal Mining Subcategory
Section 3.0       Best Management Practices

       This section the use of sedimentation ponds in arid and semiarid regions, presents the
theory behind BMP implementation, presents modeling techniques that aid in BMP design and
prediction of BMP effectiveness, and describes the site-specific sediment control measures and
techniques that may be employed.

3.1    Sediment

       In arid and semiarid watersheds, sediment can be defined as all material transported by
surface water drainage, including dissolved, total suspended, and settleable solids and bedload.
In this environment, climate, topography, soil, vegetation and hydrologic components all
combine to form a hydrologic balance that is naturally sediment rich.  The dynamic fluvial
systems in these watersheds depend upon a continuous source and flow of sediment to maintain
the existing natural sediment balance. Consideration of the importance of sediment balance in
this region is as critical as the availability of water.

3.2    Sedimentation Pond Use and Impacts in Arid and Semiarid Regions

       The numeric effluent limitations established at 40 CFR part 434 for discharges in mining
and non-process areas were based upon the treatment  capabilities of sedimentation ponds, with
nominal consideration of the impacts on the environment in the Western Region.
Implementation of sedimentation ponds to meet these numeric effluent limitations has taken
precedence over SMCRA's requirement to minimize possible impacts to the hydrologic balance.

       Reliance on sedimentation ponds as the primary technology to control sediment and to
achieve effluent limitations has resulted in the construction and operation of a significant number
of ponds at coal mining and reclamation operations in the arid and semiarid west (Western Coal
Mining Work Group, 1999a). While sedimentation ponds may be capable of achieving the
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sediment concentration reductions necessary to meet EPA discharge limitations, the net effect of
achieving those reductions can represent a disruption of the hydrologic balance (Doehring,
1985). In summary, sedimentation pond use in arid and semiarid western regions can:
       •      Require significant additional surface disturbance;
       •      Result in environmental harm through the disruption of hydrologic balance;
       •      Adversely affect valuable riparian or aquatic communities; and
       •      Create contention during the administration of basin water rights.

3.2.1  Surface Disturb an ce

       Due to topographic constraints, lease boundary constraints, and a high occurrence of
ephemeral and intermittent drainage within western surface coal mine permit areas,
sedimentation ponds are often constructed within natural drainage ways that convey surface
runoff from both disturbed and undisturbed  areas (Simons. Li & Associates, 1982).  The larger
volumes of runoff and sediment from these combined areas must be detained long enough to
achieve CWA effluent limitations, requiring the construction of larger ponds and the disturbance
of larger surface areas. With the establishment of the SS limits at 40 CFR part 434,
sedimentation ponds were upgraded through expansion and new ponds were designed to increase
detention times  by providing larger volume  capacity.

       As an example of the significant impact of sedimentation ponds in arid and semiarid
environments, the Western Coal Mining Work Group provided the following information from
four coal mining sites. A breakdown of the number of sedimentation ponds being used, area
disturbance and acres of watershed drainage at each mine site is presented in Table 3a. The
Pittsburg & Midway Coal Mining Company's  McKinley Mine in New Mexico uses 79 ponds,
BHP Coal Company's Navajo Mine in New Mexico uses 30 sedimentation ponds, and
Pacificorp's Dave Johnston Mine in Wyoming operates 14 sedimentation ponds. There are
currently 149 sedimentation ponds with the  potential to impound 4,500 acre-feet of water at the
Peabody Western Coal Company's Black Mesa Mine in Arizona. The total area of disturbance
from the implementation of these sedimentation ponds is approximately 887 acres, resulting in

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                                   Development Document - Western Alkaline Coal Mining Subcategory
an average of 3.3 surface acres disturbed per sedimentation pond.

Table 3a:    Area Disturbance and Watershed Drainage of Sedimentation Ponds at Four
             Western Mine Operations (Western Coal Mining Work Group, 1999a)
Mine Site
Black Mesa Mine
McKinley Mine
NavajoMine
Dave Johnston Mine
Total
Number Of
Sedimentation Ponds
149
79
30
14
272
Acres
Disturbed
540
211
100
36
887
Watershed Acres
Draining Into Ponds
45,720
7,050
4,331
4,567
61,668
       In contrast, Bridger Coal Company's operation in southern Wyoming (Section 5, Case
Study 2) has successfully applied alternative sediment control measures for over 5,260 acres
with only 3.9 acres of additional disturbance.  If sedimentation ponds had been implemented at
this site, the extensive surface area affected by mining and the drainage density would require
operation of roughly 200 sedimentation ponds disturbing roughly 660 acres to control all runoff
during the life of the mine.

3.2.2  Water Impoundment

       Sediment control historically has focused on the capture of surface water runoff in
sedimentation ponds located on the bottom periphery of disturbance areas (Western Coal Mining
Work Group, 1999a). Surface water runoff contained in a sedimentation pond may evaporate,
and therefore, may not be available for downstream or consumptive uses.

       Sedimentation ponds typically are sized to treat or contain the combined sediment and
runoff volume resulting from a 10-year, 24-hour storm  event (Appendix C: 19 NMAC
8.2.20.2014, 1997). A result of the implementation of this design in arid and semiarid regions is
that, for the majority of storm events, downstream channel flow is either eliminated or
significantly attenuated.  Loss of runoff water, through the storage of runoff in sedimentation
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ponds, evapotranspiration, and localized infiltration, can significantly affect the local hydrologic
balance, downstream resources, ground water hydrology, and the spatial pattern of alluvial
recharge (Doehring, 1985).

       Sedimentation ponds have the potential in some cases to disrupt hydrologic balances and
impact associated environmental resources. Downstream surface runoff volumes may be
drastically reduced or completely eliminated if non-discharging structures are used for sediment
treatment, and typically are reduced 80 to 90 percent below pre-mining flow rates when
discharging ponds are used for water treatment (Western Coal Mining Work Group, 1999a).
Disruption of flow volume at this magnitude is a concern in arid and semiarid regions.  Avoiding
or minimizing disruption to  stream flow is also a "key program objective and activity to be
undertaken in the next decade" by the Water Quality Criteria And Standards Plan-Priorities for
the Future (U.S. EPA, 1998).

       The National Mining Association employed computer modeling techniques to predict
BMP and sedimentation pond performance and resulting sediment yield at non-process areas for
three representative model mines in the arid and semiarid west (Western Coal Mining Work
Group, 1999c).  Details of these prediction studies are presented in Section 5, Case Studies  1, 2,
and 3, and in Appendix D of this document.  In a model of the Desert Southwest Coal Region,
the maximum storage capacity of sedimentation ponds used for the model was 60 acre-feet. This
means that out of 73 acre-feet of runoff (predicted from a 10-year, 24-hour precipitation event
for the reclaimed and adjacent undisturbed areas),  only about 13 acre-feet would pass through
the sedimentation pond. The model assumed an additional 30 acre-feet of water would be
released from the pond system to the downstream watershed by automatic dewatering over an 8-
day period. Thus, the runoff volume from the storm event that would pass through the pond and
be available to the down-drainage hydrologic system would be only 41 percent of the total runoff
volume produced by the storm.  In addition, the peak flow was predicted to be 45 cfs when
sedimentation ponds are implemented and 602 cfs when alternative sediment control BMPs are
implemented. This peak flow compares to 679 cfs predicted to occur naturally under
undisturbed conditions. Similar model results for the Intermountain and Northern Plains coal
regions resulted in a 96-97% reduction in naturally occurring peak flow when sedimentation

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                                   Development Document - Western Alkaline Coal Mining Subcategory
ponds are used to meet numeric limits, compared to a 33-38% reduction in naturally occurring
peak flow when using alternate sediment controls.  The result of these models demonstrate that
the use of alternate sediment control systems increases the amount of precipitation runoff that is
available to the drainage area.

       BMP systems minimize disruption to the hydrologic balance through the use of alternate
sediment controls (Western Coal Mining Work Group, 1999c). Case Study 1 predicted that, with
BMP system application in the Desert Southwest, approximately 73 acre-feet of water would be
available as a result of the receipt of a 10-year, 24-hour precipitation event. By depriving
downstream channels of small but relatively frequent flows, channel geometry is not maintained
(Doehring, 1985). Unused channels are modified by the processes of mass wasting; caving
banks and slope processes that destroy the channels and eliminate their ability to convey flows of
sediment and water. In cases where some flow is maintained, a small, "underfit", inner channel
is produced.  While sedimentation ponds may be capable of achieving the sediment
concentration reductions necessary to meet EPA discharge limitations, the net effect of achieving
those reductions is often the triggering of large bursts of sediment produced by channel
adjustments.  When substantial flows return, either due to a high yield storm or due to removal of
the sedimentation pond, accelerated erosion and flooding can be expected.

       Many western  states have long recognized the social and economic importance of their
limited surface water and ground water resources and have instituted water rights procedures to
prioritize and allocate beneficial usage.  However, in order to achieve existing CWA effluent
criteria for coal mining operations, regulations and guidelines emphasizing the construction of
sedimentation ponds may discourage beneficial usage of water. Regardless of the magnitude of
drainage area controlled, the construction and operation of sedimentation ponds reduces the
amount of surface runoff available for downstream users. The loss of surface water runoff and
ground water recharge due to sedimentation ponds  continues to be an issue in water rights
negotiations (Western Coal Mining Work Group, 1999a).
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3.2.3  Sediment Retention

       In arid and semiarid western coal mine regions, large amounts of sediment are readily
and naturally transported. Sediment is an important and integral part of these hydrologic
systems.  In fact, these systems depend upon a continual source and flow of sediment to maintain
the existing natural sediment balance.

       In order to predict the amount of sediment that will be transported out of a representative
model mine in an arid western watershed, the Western Coal Mining Work Group implemented
SEDCAD 4.0 (Western Coal Mining Work Group, 1999c). With the implementation of
sedimentation ponds to comply with numeric effluent guidelines, SEDCAD 4.0 estimated that
0.0 acre-feet of sediment per year would be transported out of the watershed.  With
implementation of appropriate alternative sediment control BMPs, SEDCAD 4.0 estimated that
an average  annual sediment yield of 6.7 acre-feet would be transported out of the watershed,
which closely approximates the 8.3 acre-feet per year estimated sediment yield for an
undisturbed watershed (see Section  5.1, Case Study 1). The essential containment realized by
the sedimentation ponds represents a gross disruption of sediment movement through the fluvial
system.

3.2.4 Scouring  and Seeps

       SMCRA requires operators of coal mines  to prevent, to the extent possible, additional
contributions of sediment to receiving waters, and to protect the balance of the hydrologic
system. Since sediment is an integral part of the arid and semiarid geomorphic and hydrologic
system, maintenance of background levels of sediment in mine discharges is crucial to
maintaining the hydrologic balance (Water Engineering and Technology, 1986). At times of
normal runoff in  this region, sedimentation ponds can intercept and detain virtually all flow and
waterborne sediment, including both the natural and the mining-generated components
(Doehring,  1985). Additionally, clean water that  is released from the ponds can accelerate
erosion in channel beds in the reach immediately  downstream (Williams and Wolman, 1984).
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       The combination of localized scour (increased erosion caused by sediment-free water)
coupled with attenuated flows can cause the incised channel width to decrease within this reach.
Riparian and other hydrophytic vegetation are limited in arid and semiarid regions, and
fluctuations in water tables fed by surface water runoff can cause these valuable biologic
communities to shrink considerably or even disappear.

       Another potential impact from the implementation of sedimentation ponds, as the only
means to control sediment, is the  occurrence of intermittent seeps that have been observed and
monitored at several sites since the early  1980s (Western Coal Mining Work Group,  1999a).
Intermittent seeps reported at Peabody Western Coal Company's Black Mesa Mine have
developed as a result of impounded water interacting with local geologic materials in the vicinity
of the sedimentation pond embankments. These seeps are expected to persist intermittently at
several pond locations until the ponds are removed and reclaimed.  Concerns expressed by local
residents resulted in an EPA requirement to study the seeps, report the findings of the study, and
develop a plan to mitigate the seeps as part of the Black Mesa NPDES permit. The formation of
springs and seeps in the immediate downstream vicinity of sedimentation ponds also can result
in a localized proliferation of vegetation that can encroach on channels (Williams and Wolman,
1984).

3.3    Sediment Control BMPs

       Erosion and sediment controls are used to reduce the amount of soil particles that are
carried off of a land area and deposited in receiving water.  Soil erosion and sediment control is
not a new technology.  Many sediment control  BMPs already are an integral part of mining and
reclamation operations and do not require additional engineering designs or construction. For
this reason, implementation can require minimal additional labor and the use of conventional
equipment and materials that already are  on site and operational. Most BMPs are adaptable to
all regions of the country, with the exception of extremely arid regions of the West (Montana
DEQ, 1996). In these  regions, conventional BMP designs may need to be refined to  account for
high evaporation rates, and new or modified BMP options should be explored. The USDA Soil
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Conservation Service and a number of state and local agencies have been developing and
promoting the use of sediment control technologies for years (EPA, 1992).

       Design and application of erosion and sedimentation control technology has improved
since the passage of SMCRA and since EPA's promulgation of technology-based numerical
effluent limits. Extensive monitoring and case studies have been performed on arid and semiarid
lands to characterize the nature and extent of erosion occurring within these areas. Computer
sedimentation modeling of arid and semiarid fluvial systems has advanced significantly,
evolving into site-specific models that are sensitive to the highly variable environmental factors
found within the region. Designers and manufacturers of erosion and sedimentation control
products have also contributed significantly to the improvement of BMPs. Manufacturers are
providing improved and innovative products capable of addressing generic and specific sediment
and erosion control problems.  Advanced computer prediction models, comprehensive
environmental erosion and sediment management practices, and new erosion control materials
and equipment form the core of the BMPs that may more appropriately address sedimentation in
arid and semiarid coal mining regions.

       Using BMP systems designed to address site-specific erosion and sedimentation concerns
using current modeling techniques, it is now possible to effectively control erosion and sediment
transport, while concurrently minimizing disruption of the fluvial balance. Allowing runoff to
"flow naturally" from disturbed and reclaimed areas is environmentally and socially preferable to
non-consumptive retention in sedimentation ponds that is accompanied by episodic releases of
runoff resulting in sediment imbalances that are potentially disruptive to watershed fluvial
morphology.

       In summary, BMPs may be either short-term or long-term in their effectiveness.
Methods and practices that are capable of harvesting and conserving moisture, limiting soil
detachment and erosion, or accomplishing both simultaneously with reasonable economic
expenditures find ready acceptance and wide use throughout the mining industry (Western Coal
Mining Work Group, 1999a). Many types of erosion and sediment control BMPs and methods
are currently used by the coal mining industry within reclaimed areas,  serving to reduce the total

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sediment impoundment volume required to treat runoff to numerical effluent standards.
Increased focus on the implemention of site-specific sediment control BMPs serves to address
sediment at the source, enhance vegetation growth and stabilize reclaimed lands.

       BMPs can be categorized into two descriptive types, either Managerial or Structural.
These may vary over the life of the disturbance or reclamation period, depending upon changing
site conditions. The characteristics and components of each type of BMP are presented in
greater detail in Sections 3.3.1 and 3.3.2.

3.3.1  Man agerial BMPs

       Managerial sediment control BMPs include project design and planning methods used to
protect water quality and minimize erosion and sedimentation.  Managerial BMPs are employed
prior to, during, and following reclamation of a site. Managerial methods that may be employed
at a site are listed in Table 3b.
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Table 3b:    Examples of Managerial Sediment and Erosion Control Practices (Western
             Coal Mining Work Group, 1999a)
Managerial Sediment
Minimizing the Area of
Disturbance
Appropriate Application
Timely Placement
Control Sediment at Source
Contemporaneous
Reclamation
Periodic Inspection,
Maintenance and
Replacement
Implementation Technique
Surface disturbances are minimized to that specific area necessary to
conduct the mining and reclamation.
BMPs are judiciously used based on erosion and sedimentation
control capabilities, site-specific environmental conditions, and
sedimentation predictions.
Structures are placed at the most appropriate time to function properly
and effectively during their anticipated use period.
BMPs are implemented at the source of sediment. Terraces, check
dams, straw bales, riprap, mulch, silt fences, etc. are implemented to
control overland flow, trap sediment in runoff or protect the disturbed
land surface from erosion.
After mineral extraction is complete, disturbed areas are reclaimed as
rapidly as is practicable and rehabilitated for the designated post-
mining land use.
BMPs are periodically inspected during construction and use. Based on
these inspections, maintenance is scheduled and adequately performed.
When structures can no longer be reasonably maintained, they are
replaced if necessary . When BMP structures are no longer needed, they
are removed, if necessary, and the disturbed area reclaimed. Most
BMPs are installed as integral components of the surface drainage
system and their removal is not needed.
3.3.2 Structural BMPs

       Structural BMPs are the physical structures, methods, practices, and products
implemented and used to achieve erosion and sedimentation control. These BMPs are combined
with managerial practices and monitoring plans to form complete BMP systems for a given site.
Structural sediment control BMPs primarily include regrading, revegetation, sediment trapping,
and control of surface runoff. Examples of common structural sediment control BMPs are listed
in Table 3c.  EPA recognizes that Table 3c is not inclusive of all sediment control BMPs that are
appropriate for use in arid and semiarid regions.  Numerous additional BMPs and BMP
combinations currently exist and are being used effectively.
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Table 3c:     Examples of Structural Best Management Practices (Western Coal Mining
             Work Group, 1999a, Carlson, 1995, Bonine, 1995, Toy and Foster, 1998, U.S.
             Mining and Reclamation Council of America, 1985)
BMP
Straw Bales
Terraces or Benches
Deep Ripping
Contour Berms
Diversion Channels
Check Dams
Interceptor Ditch -
Slope Drain
(Contour Ditch)
Mulch
Mulch Crimping
Geotextiles
Sediment Control Characteristics And Design Techniques
Inhibit surface runoff and stop the movement of sediment. Bales are used
across medium slopes or at the toes of steep slopes.
Reduce slope lengths and water velocities and increase infiltration. Constructed
as wide (10'-20') horizontal, level or slightly reverse sloping steps in intervals
down the slope on or near contours.
Breaks compacted layers, heavy clays, and soil-minesoil interfaces. Increases
infiltration and reduces flow velocities. Ripping loosens and mixes subsoil and
allows root penetration and subsurface water storage.
Control or divert surface runoff flow. Care must be taken to assure a level top
surface with no low spots where breaching could occur. Berm height varies
from one to three feet. Berms that will be in existence for longer than one year
are vegetated to reduce erosion.
Convey runoff from points of concentration across, through, along, and around
areas to be protected. Designed for peak flows based upon a 10-year, 24-hour
storm event. Typically two feet deep with a run-to-rise ration of 3 : 1 . Those in
existence for longer than one year are vegetated to reduce erosion.
Stabilize channel grades and control channel head cutting. Reduce or prevent
excessive erosion by reducing velocities in diversions, conveyances and
sedimentation pond inlets or by providing partial channel sections or structures
that can withstand high flow velocities. Dam height is dictated by flow amount,
channel slope, and available cross sectional area. Sized to pass 10-year, 24-
hour runoff event.
Ditches are placed horizontally at vertical intervals on long slopes to reduce the
effective slope length, slow runoff, reduce erosion and enhance sediment
deposition. They are generally 1.5 feet deep with a run-to-rise ration of 2: 1.
Ditches are spaced approximately 50 feet apart horizontally.
Temporary soil stabilization. Used to increase infiltration, retain water, add
surface roughness, decrease runoff, protect soil surface from erosive action of
raindrops, and to enhance seedbed for vegetative growth. When used together
with seeding or planting, mulching can aid in plant growth by holding the
seeds, fertilizers, and topsoil in place. Helps to retain moisture and insulate
against extreme temperatures. In general, higher mulch application rates
(Ibs/acre) are needed for western regions.
Increases the effectiveness of mulch against surface erosion by water and wind.
It is accomplished by tacking mulch materials into the soil surface using blunt
or notched disks that are forced into the soil.
Geotextiles, when used alone, can be used as matting to stabilize runoff flow.
Geotextile matting also can be used on recently planted slopes to protect
seedlings until they become established or as a separator between riprap and
soil.
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BMP
Roughened Surface -
Control Discing
Pitting
Sediment Traps
Contour Plowing
Complex Slope
Drainage to Pit
Cover Crop
Regrading
Livestock Grazing
Irrigation
Landscape
Configuration
Revegetation
Toe Drain Ditches
Sediment Control Characteristics And Design Techniques
Increases infiltration. Surface roughening is commonly accomplished through
the use of agricultural techniques including discing, plowing, contour
furrowing, and land imprinting.
A mechanical treatment measure which creates small, basin like depressions
that increase surface water revegetation potential of a site. Pitting as a water
conservation and erosion control measure is used on mined lands before
seeding and planting. The method has been used mainly in arid or semiarid
regions where the water conservancy methods are most critical.
Provide small storage or detention areas without special inlet or outlet controls.
Constructed by excavation, or by creating an impoundment with logs, silt fence
or brush barrier/filter cloth as a low head dam.
Prevents rill formation. Furrows formed by contour plowing also add
roughness and enhance infiltration.
Slopes graded with three segments: upper convex, middle straight, lower
concave. Straight slopes are minimized and concave slope is maximized to
reduce erosion and promote deposition on the lower slope segment.
Runoff from disturbed areas drains either directly to or is diverted to the pit.
This water evaporates or is pumped to holding ponds. Holding pond water is
discharged in accordance with NPDES requirements.
Broadcast or drill seeded. Establishes quick live cover & root system. Stubble
acts as surface roughness during winter.
Regrading to approximate original contour or other acceptable slope gradients
and configurations can substantially reduce soil loss rates. Although the
construction of complex or concave hill slope profiles offer grading challenges,
these shapes can substantially reduce soil loss rates.
Controlled livestock grazing can have positive sediment control impacts on
reclaimed areas, such as increasing vegetation cover and production, creating
surface roughening, promoting soil formation, and increasing soil microbial
populations, all of which serve to control erosion and sedimentation. It is
important to have established vegetative cover prior to allowing grazing on
reclaimed land.
If there is not enough rainfall on the area for establishing vegetation, the area
can be irrigated.
Establishes reclaimed topography that is stable with surrounding terrain and
climate. Configuration measures include shorter slopes, complex slopes, and
proper drainage profiles.
Adds soil stability and surface roughness, reduces rainfall erosion, and
physically secures soil making it less erosive.
Store or divert slope runoff. These channels are open, of any cross sectional
shape and are constructed at the toe of exposed slope surfaces.
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3.3.3  BMP Implementation

       Selection of sediment control BMPs for mining or reclamation activities should be based
on site-specific conditions.  The BMP plan should be designed to: minimize the amount of
disturbed soil, control runoff flowing across a site, remove excess sediment from onsite runoff
before it leaves the site, and meet or exceed local or state requirements for sediment and erosion
control plans.  In most situations, a combination of BMPs is necessary to adequately control
sediment and erosion. Moreover, these BMPs must be properly designed, implemented and
maintained in order to be effective. Implementation of managerial practices and structural
sediment control BMPs, either in addition or as an alternative to sedimentation ponds, should be
expected to:

•      Maintain adequate "natural  sediment loading" to avoid disruption of the fluvial system,
       while preventing impacts to environmental and biologic resources in watersheds affected
       by mining;
•      Minimize reductions in downstream runoff;
•      Reduce unnecessary additional disturbance of surface acreage; and
•      Restore or improve riparian and natural vegetative species.

       Appropriate alternative sediment control BMPs can be designed and implemented using
site-specific design evaluations of the various disturbance activities anticipated over the life of
the mining or reclamation operation. BMPs may be used singly or in combination to effectively
control and minimize erosion and sedimentation from disturbed areas.

       BMP plans should consider the background environmental conditions (i.e., size of site,
soil types, drainage pattern, rainfall data, receiving channels, and land use) to establish
reasonable and acceptable implementation and monitoring design criteria.  The design should
include modeling of disturbance phases to determine the control and treatment practices and
methods to be used to ensure compliance with the site-specific performance-based standards
during the various disturbance  and  reclamation phases.  BMP designs should demonstrate that

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erosion will be controlled, deepening or enlargement of stream channels will be prevented,
disturbance of the hydrologic balance will be minimal, and additional contributions of sediment
of stream flow and runoff outside the permit area will be prevented to the greatest extent
possible. BMP design, construction, implementation, and monitoring represent the complete
BMP system for a given location.

       The key to the effective planning and implementation of a BMP system is deployment
flexibility.  For a given situation, there may be several BMP combinations that will adequately
control erosion and sedimentation.  The type of BMP that is most effective may also change
through time. For example, during the early stages of establishing vegetation on non-process
areas, livestock grazing represents a potentially disruptive land use activity. However, once the
vegetation is firmly established, livestock grazing can act as an effective BMP.  The operational
preferences of mining companies can result in the design and use of a variety  of different
combinations of sediment control practices for essentially similar areas. The critical goal that
must be realized is the adequate control of surface erosion and retention of sediment in order to
meet the site's water quality requirements. The primary purpose of sediment control BMPs is to
control sediment at the source and to minimize erosion caused by wind and water.  A sediment
control plan should demonstrate that all exposed or disturbed areas are stabilized to the greatest
extent possible.

       Sediment control BMPs can be categorized according to function as follows:
Topographic, Slope Erosion, Flow Structures, Soil Conservation, and Vegetation. BMPs that
fall within these categories may be universal or limited in their application. For example,
reconstructed drainage channels usually are limited to use within low-lying reclaimed areas,
while permanent vegetation typically is established throughout a reclaimed landscape.
Appropriate sediment control BMPs are designed and implemented using site-specific
evaluations of the various activities anticipated during mining or reclamation  operations.
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3.3.3.1        Topographic BMPs

       In order to prevent unnatural sedimentation, mined land surface areas should be
reclaimed to a grade necessary to control surface water runoff and promote appropriate drainage
and stability.  Terrace and bench-type grading can prevent slides and sedimentation while
promoting slope stability.  Topographic BMPs include:

•      Planning post-mining topography using modeling to mimic approximate original contour
       or pre-mining natural, background erosion and sedimentation yields;
•      Designing and implementing a BMP plan that will approximate natural drainage as
       closely as possible;
•      Choosing sediment control structures according to review of existing topography, flow
       direction and volume, outlet location, and feasibility of construction;
•      Backfilling and grading to approximate original topography or other acceptable slope
       gradients and configurations.  Blending disturbed areas into the surrounding terrain; and
•      Eliminating unstable areas to the greatest extent possible.

3.3.3.2        Slope Erosion

       BMPs that control  slope erosion are implemented to stabilize and protect slopes against
surface erosion.  Slope surfaces should be mulched, vegetated or otherwise stabilized to
minimize sediment  movement, and, on a site-specific basis, to address particular erosion problem
spots according to need. Construction of terraces, benches, and other grading or drainage control
measures can be utilized to prevent erosion and ensure slope stability.  These structures should
be designed to be non-erodible and to carry short-term, periodic flows at non-erosive velocities.
These BMPs  often help stabilize steeply sloped areas until vegetation can be established. BMPs
that serve to control erosion and  sedimentation from slopes include:

•      Limiting slope length according to modeling prediction of surface runoff sediment yield;
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•      Creating slope shapes which promote stability through protective surface configurations
       (concave vs. convex, simple vs. complex);
•      Providing non-erosive mulches or surface cover materials (e.g., durable rock fills that
       limit erosion through adequate surface protection); and
•      Segmentation of slopes through construction of terraces or benches to limit slope length
       and provide protected drainage.

3.3.3.3        Flow Structures

       Hydrologic flow structures are implemented to ensure that additional contributions of
sediment to stream flow and to runoff outside the permit area are prevented to the greatest extent
possible. These BMPs are implemented to direct runoff away from exposed or unstable surface
areas, to control runoff volume and velocity, and to provide water for establishment of vegetative
cover.  These structures should be inspected regularly, compacted according to applicable
standards, and maintained properly to ensure maximum effectiveness.  BMPs that utilize flow
structures include:

•      Implementing diversions, reclaimed channels, drains, terrace drains, down-drains, and
       ditches capable of conveying surface water runoff from designated worst-case storm
       events and worst-case watershed disturbance conditions around, through or from the
       disturbed/reclaimed area;
•      Implementing flow structures  in a manner that reduces runoff flow velocity and thus
       reduces loosening or removal  of soil particles; and
•      Designing flow structures with adequate sizing, configuration and protective linings to
       provide stable watercourses for anticipated flow volumes and velocities.

3.3.3.4        Soil Conservation

       BMPs that are implemented to conserve soil tend to protect exposed surfaces against the
erosive effects of wind and water by manipulating the soil surface or providing surface cover

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amendments. A sediment control BMP plan should demonstrate that all exposed or disturbed
areas are stabilized to the greatest extent possible, as quickly as possible following disturbance.
Surface erosion protection practices and materials include:

•      Mulching with organic or inorganic materials or applying geotextile fabrics;
•      Preserving existing vegetation;
•      Establishing quick-growing cover crops with annual or perennial plant species; and
•      Roughening exposed surfaces. Surface roughening is commonly accomplished through
       the use of agricultural techniques including discing, plowing, and contour furrowing.

3.3.3.5        Vegetation

       Land in arid and semiarid climates tends to have relatively low vegetation cover and
productivity, particularly where annual rainfall is less than 9 inches per year.  Total vegetation
cover values frequently fall within the range of 5 to 20 percent.  Yearly vegetation production
tends to be low, with most reclaimed areas producing between 500 to 1,000 pounds per acre
annually (Western Coal Mining Work Group, 1999a).

       Preserving existing vegetation or vegetating disturbed soil as soon as possible after
surface disturbance is the most effective way to control erosion (U.S. EPA, 1992).  A vegetative
cover reduces erosion potential by: (1) shielding the surface from the direct erosive impact of
raindrops, (2) reducing sediment runoff to downstream areas, (3) filtering sediment, (4)
improving the soil's water storage capacity, (5) slowing runoff and allowing sediment to drop out
or deposit, and (6) physically holding the soil in place.

       Establishment of vegetation can be a short-term (temporary) or long-term (permanent)
method for controlling erosion and sedimentation.  Plant species are selected based upon land
use, growth  conditions, and environmental requirements.  Temporary seeding should take place
as soon as practicable after the most recent land disturbing activity. In arid and semiarid regions
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where the climate prevents fast growth, temporary seeding may not be effective (U.S.EPA,
1992). In these regions, mulching may be more appropriate for short-term stabilization.

       Common goals for permanent vegetation include the establishment of adequate cover,
production, and diversity to support designated post-mining land use(s), and to protect the soil
from excessive surface erosion.  Proper seedbed preparation, the use of high-quality seeds, and
the application of mulch may be necessary for effective erosion control. In arid and semiarid
regions, irrigation and the addition of topsoil or other soil  amendments may be required to make
conditions more suitable for plant growth. Although the use of native species is recommended,
both non-native and native plant species may be used for routine and specialized seeding and
transplanting programs.  Bioengineering or specialized plantings may be used singly or in
combination with hard structures to achieve erosion control and protect and enhance the
effective life of critical erosion and sedimentation control  structures or features.

       Seed mixtures are an integral component of a BMP reclamation plan and are an important
component in vegetative success.  A diverse seed mixture, coupled with appropriate water
management, accelerates early plant community development and diversity. Mixtures and
application rates dramatically influence vegetation germination, establishment and development.

       Land use can have a dramatic effect on a reclaimed area's vegetation characteristics.
Reclamation land use in the arid and semiarid western United States is primarily rangeland with
livestock grazing normally a part of the post-mining land use.  Controlled grazing can be used
effectively to promote vegetation growth and development, soil stability and surface water
hydrology. Livestock grazing has been successfully used  as part of BMP systems to increase
vegetation density on most western coal mine non-process areas.

3.3.3.6        Geochemistry

       The geochemistry of the western arid and  semiarid coal regions, which is generally
alkaline, differs from that of the eastern coal regions. Western alkaline coal regions, unlike

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eastern regions, contain large quantities of sandstone and limestone that contain high levels of
calcium and carbonate minerals (e.g., calcite, dolomite).  These minerals inhibit H+ formation
from pyrite via the following equation (Hornberger, 1981; Williams, 1982; Perry and Brady,
1995):

       FeS2 + 4 CaCO3 + 3.75 O2 + 3.5 H2O - Fe(OH)3 + 2 SO42' + 4 Ca2+ + 4 HCCV

       Dissolved carbonate minerals also promote precipitation of dissolved iron and other
metals ions to further neutralize acidity.  Studies have shown that a 3% (or greater) concentration
of carbonate minerals will produce alkaline mine drainage (CoalMine Drainage Prediction and
Pollution Prevention in Pennsylvania, 1999).  The net alkalinity of drainage from these coal
regions indicates high concentrations of carbonate that will counter potential acidity. As a result,
the production of acid mine drainage is much less typical due to the inherent buffering capacity.

       In natural  undisturbed conditions, surface water samples in the arid/semiarid western
United States can register values for total iron as high as 40,000 mg/L (or 4%), due to the
sediment that is collected as part of the water sample. The primary mineral responsible for the
high total iron readings is often magnetite, which is often visible on the floor of arroyos.

       In addition, in the western coal regions there is a low occurrence of pyrite which, along
with dissolved iron, is the common culprit of acid mine drainage generation. Instead, iron often
occurs in the form of magnetite (Fe3O4), a solid, inert iron oxide that has no acid-forming
potential.  The following data from a USGS website support the commenter's assertion that there
is comparatively less iron (average of almost 1:3) and pyritic sulfur (average of over 1:5) in
western coal versus eastern coal (Table 3d):
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Table 3d:
Summary of Coal Quality Data in Western and Eastern Coal Regions
        Western Coal Region1                Eastern Coal Region2

Total Iron (mg/L)
Sulfate (%)
Pyritic Sulfur (%)
Total Sulfur (mg/L)
N
1258
1045
1045
1191
Range
110-52,000
0 - 0.69
0-4.5
15-31,000
Average
5652
0.03
0.25
3722
N
4511
3623
3905
4401
Range
72 - 120,000
0-25.54
0- 12.1
4 - 20,000
Average
15,082
0.07
1.32
1072
Data from http://energv.er.usgs.gov/coalqual.htm : National Coal Resources Data System, U.S. Coal Quality
       Database.
'Data from the following States were considered under the Western Coal Region: AZ, CO, MM, WY
2Data from the following States were considered under the Eastern Coal Region: AL, KY, MD, OH, PA, TN, VA,
       WV

       Of the forms of iron that can exist in coal mine discharges, only pyrite and dissolved iron
have acid-forming potential at pH >6.  Dissolved iron contained in coal mine drainage can come
from multiple sources, one of which is pyrite.  The series of reactions below characterize pyrite
oxidation  and the resulting acid formation.  As can be seen, dissolved iron (Fe2+, Fe3+) is an
intermediate product of acid formation from pyrite.

       1)      FeS2 (pyrite)(s) + 3.75 O2 + 3.5 H20 = Fe2+ + 2 SO42' + 2 FT
       2)      Fe2+ + 0.25 O2 + FT = Fe3+ + 5 H2O
       3)      FeS2 (pyrite)(s) + 14 Fe3+ + 8 H2O =  15 Fe2+ + 2 SO42' + 16 FT
       4)      Fe3+ + 3 H2O = Fe(OH)3(s) + 3 FT

       Studies have shown that, in most coal mine drainage, an abundance of dissolved iron
indicates FT formation from pyrite oxidation (Rose  and  Cravotta, 1999).  Therefore, even if
pyrite is present (which is unlikely in the western coal regions), the effect of its presence  will not
escape detection so long as dissolved iron is measured.  Other forms  of iron, such as iron
hydroxide (Fe(OH)3(s)) and magnetite (Fe3O4(s)), are insoluble and unreactive at pH > 6.  In
fact, encouraging magnetite precipitation is being investigated for use in treatment of acid mine
drainage (Morgan, 2001).
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       EPA has established the applicability of the Western Alkaline Coal Mining Subcategory
as follows: "This subpart applies to drainage at western coal mining operations from non-process
areas, brushing and grubbing areas, topsoil stockpiling areas, and regraded areas where the
discharge, before any treatment, meets all the following requirements: pH is equal to or greater
than 6, dissolved iron concentration is less than 10 mg/L, and net alkalinity is greater than zero."
This applicability is consistent with the definitions of both acid and alkaline mine drainage, and
with EPA recognition that net alkalinity or acidity is a the defining characteristic of acid mine
drainage in terms of the potential to form more acidity.

3.4    Prediction Models for BMP Design and Implementation

       The major factors affecting soil erosion are soil characteristics, climate, rainfall intensity
and duration, vegetation or other surface cover, and topography. Understanding the factors that
affect erosion makes it possible to predict the extent and consequences of onsite erosion (U.S.
EPA, 1992).  Although an estimate  of sediment erosion and deposition can be derived over time
using water samples or sediment accumulation markers, this method of erosion prediction can be
time consuming and labor intensive. Prior to implementation of sediment control BMPs,  it is
important to determine both the quantity of sedimentation and the sedimentation patterns  that
can be expected. Sites must be assessed to determine pre-mining drainage patterns and
topography, to quantify effects of storm runoff and the yield of coarse- and fine-grained
sediment,  and to determine morphologic evolution of streams, washes, and arroyos.

       Although an estimate of sediment erosion and deposition can be derived over time using
water samples or sediment accumulation markers, these methods of erosion prediction are time
consuming and often labor intensive.  The collection of sufficient soil-loss data from natural
rainfall events on erosion plots to permit confidence in the results of statistical analyses has
proven to be a long-term, expensive, and inefficient undertaking (Toy, 1998).  Sediment
transport can be predicted with reasonable accuracy using computer models developed for this
purpose during the last 20 years.

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       Computer models have been developed to assess and predict erosion, soil loss, and
sediment yields from undisturbed lands experiencing overland flow, from lands undergoing
disturbances, and from newly established or reclaimed lands. Computer models are commonly
used to evaluate watershed response and assess impacts of land use and are capable of
determining the effectiveness of BMPs on erosion control and sediment production prior to field
use.  These models are particularly valuable in arid and semiarid areas because the infrequency
of precipitation discourages compilation of data from instrumented watersheds. When
calibrated, the models provide a means for comparing sediment loss under undisturbed (premine)
and reclaimed mine land conditions (Peterson, 1995). Examples of soil loss prediction models
include:

              SEDCAD 4.0
             RUSLE
             EAST
              SEDIMOT II
             MULTSED

       The efficiency and accuracy of these models has improved dramatically as extensive
environmental  databases and product specifications have been developed. A great deal of study
has been performed regarding mined land and new erosion and sedimentation control and
treatment products, to develop and verify these modeling programs. Most importantly, the
models provide a constant base from which to evaluate pre-mining and post-mining sediment
delivery (Peterson, 1995).  Computer simulations allow mine operators to determine which
combination of managerial and/or structural BMPs will be most effective at controlling sediment
and erosion at a specific mining or reclamation site.

3.4.1 Revised Universal Soil Loss Equation  (RUSLE)

       The Universal Soil Loss Equation (USLE) developed in 1961, was designed to predict
average annual soil loss caused by sheet and rill erosion. The USLE can estimate long-term

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annual soil loss and guide conservationists on proper cropping, management, and conservation
practices, but it can not be applied to a specific year or a specific storm event. USLE was
modified as the Modified Universal Soil Loss Equation (MUSLE) to replace USLE's rainfall
factor with a runoff factor.  The MUSLE model assumes that sediment yield is related to peak
discharge and runoff volume.

       The Revised Universal Soil Loss Equation (RUSLE), based extensively on the USLE
model and  its data, was developed to estimate average annual soil loss in larger, steeply sloped
areas and can accommodate undisturbed soil, spoil, and soil-substitute material, percent cover,
random surface roughness, mulches, vegetation types, mechanical equipment effects on soil
roughness,  hill-slope shape, and surface manipulation. RUSLE is applicable to sheet and rill
detachment only, and does not estimate gully or stream-channel erosion or compute deposition.

       RUSLE is based on a set of equations that estimate annual soil loss (soil removed from
the hillslope or hillslope segment). It was derived from the theory of erosion processes, more
than 10,000 plot-years of data from natural rainfall plots, and numerous rainfall-simulation plots.
RUSLE retains the structure of USLE (Pennsylvania Department of Environmental Protection,
1999, Renard, 1997) and takes the form of the following equation (Toy, 1998).

                                      A = RKLSCP
              Where:
              A =    Computed Soil Loss (Annual Soil Loss as tons/acre/year)
              R =    Climatic Erosivity or Rainfall erosion index - a measure of the erosive force and
                     intensity of a specific rainfall or the normal yearly rainfall for specific climatic
                     regions
              K =    Soil Erodibility Factor - Ability of soils to resist erosive energy of rain.  A
                     measure of the erosion potential for a specific soil type based on inherent
                     physical properties (particle size, organic matter, aggregate stability,
                     permeability).  Soils with a K value of 0.17 or less are considered slightly
                     erodible, and those with a K value of 0.45 or higher are highly erodible. Soils in
                     disturbed areas can be more easily eroded regardless of the listed K value for the
                     soil type because the structure has been changed.
              LS =   Steepness Factor - Combination factor for slope length and gradient

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             C=    Cover and Management Factor -Type of vegetation and cover. The ratio of soil
                    loss from a field with specific cropping relative to that from the fallow condition
                    on which the factor K is evaluated.
             P =    Support Practice - Erosion control practice factor, the ratio of soil loss under
                    specified management practices.

3.4.2  SEDCAD

       SEDCAD is a comprehensive model that enables the user to evaluate the performance of
erosion and sediment controls. SEDCAD calculates the amount of runoff and sediment
generated in response to a given precipitation event for specific soil and vegetative cover
conditions, analyzes the effectiveness of sediment/erosion control structures in meeting effluent
standards, and allows the design of cost effective sediment erosion control structures.  SEDCAD
is widely used throughout the mining industry and is the program used by the OSMRE to review
mine permits, and to design and evaluate structure performance in OSMRE's Abandoned Mine
Land Program.

       SEDCAD is a hydrology and sedimentology routing model used to simulate peak flows,
drainage volumes, and sediment yields from undisturbed and disturbed/reclaimed watersheds.
Hydrograph development and peak flow determination are based on user inputs of a design
storm (e.g., rainfall amount and duration and selection of a rainfall distribution). Hydrographs
are developed on a subwatershed basis with the input area, time of concentration, Natural
Resources
Conservation Service (NRCS) curve number, and selection of one of three dimensionless double
triangle unit hydrographs. Routing of hydrographs is accomplished by Muskingum's method
(Warner and Schwab, 1998).

       The sediment yield and concentrations of TSS and SS are also determined on a
subwatershed basis.  SEDCAD uses a subroutine that implements a method similar to RUSLE to
determine average annual sediment yield.  SEDCAD sedimentology input values may  be taken
directly from RUSLE results, allowing the two models to work in tandem.  Sediment routing is

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determined in conjunction with runoff hydrograph routing, and considers the eroded particle size
distributions of the soils exposed to rainfall and runoff. An example of combining RUSLE and
SEDCAD computer models to determine background sediment yield and predict the effects of
sediment controls is presented in Section 5, Case Study 1.

3.4.3 SEDIMOTII

       SEDIMOT II considers a number of field parameters (sediment type and concentration,
vegetation type, slope and length of filters) that affect sediment transport and deposition through
filtering materials or vegetation.  SEDIMOT II is capable of evaluating the hydraulic and
sediment response of a watershed as well as the effectiveness of detention ponds, grass filters,
and check dams (Wilson, 1984).  Flow is described by the continuity equation and by
steady-state infiltration (i.e., flow decreases linearly from upstream to downstream in the filter).
SEDIMOT II is based on the hydraulics of flow and the transport and deposition profiles of
sediment in laboratory conditions. The model does not handle time dependent infiltration or
changes in flow resulting from sediment deposition during a storm event.

       The user of the model divides the drainage basin into subwatersheds of relatively uniform
land use. A hydrograph, sediment graph, and particle size distribution are determined for each
subwatershed, routed downstream, and then combined to form a composite hydrograph, sediment
graph, and particle size distribution. In the hydrologic component of SEDIMOT II, the Soil
Conservation Service (SCS) curve number method is used to determine rainfall excess, the unit
hydrograph theory is used to calculate a runoff hydrograph, and the Muskingum procedure is
used for channel routing. An example of combining SEDIMOT II and SEDCAD computer
models to determine background sediment yield and design sediment control plans is presented
in Section 5, Case Study 2.
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3.4.4HEC-6

       The HEC-6, Scour and Deposition in Rivers and Reservoirs model was developed by the
United States Army Corp of Engineers (U.S. Army Corp of Engineers, 1999).  It is a
one-dimensional, movable boundary, open channel flow, numerical model. HEC-6 was designed
to simulate and predict changes in river profiles resulting from scour and/or deposition over
moderate time periods (typically years, although applications to single flood events are possible).
HEC-6 calculates water surface and sediment bed surface profiles by computing the interaction
between sediment material in the stream bed and the flowing water-sediment mixture.

       HEC-6 simulates the capability of a stream to transport sediment, given the yield from
upstream sources.  Prediction of sediment behavior requires that the interactions between the
flow hydraulics, sediment transport, channel roughness, and related changes in boundary
geometry be considered. HEC-6 is designed to incorporate these interactions into the simulation.
Channel bed elevation changes resulting from net scour or net aggradation are reported after a
series of uniform discharges of finite duration have been simulated. In this way, a continuous
hydrograph is simulated by a histogram. HEC-6 can be used to predict the impact of land
manipulation or construction on the river hydraulics, sediment transport rates, and channel
geometry.

3.4.5 MULTSED

       The Watershed and Sediment Runoff Simulation Model for Multiple Watersheds
(MULTSED) simulates the sedimentation processes of detachment, transport, and deposition.
MULTSED was developed at Colorado State University with support from EPA and the USDA-
Forest Service. In a 1990 comparison of MULTSED, ANSWERS, KINEROS, PRMS, and
SEDEVIOT II, MULTSED was found to be the best overall model for semiarid lands (WET,
1990).
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       One of MULTSED's strengths is its simulation of channel processes, which often have a
greater impact than hillside processes in a semiarid environment. MULTSED represents the
watershed as a cascade of planes and channels and simulates channel infiltration, erosion and
deposition in addition to calculating sediment transport by size fraction. Rainfall is input
independently for each plane, and runoff is simulated as a kinematic wave with laminar
characteristics.  Channel runoff is simulated as a kinematic wave with finite difference.
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Section 4.0      Benefits of Sediment Control BMPs

       The use of sediment control BMPs as an alternative or in addition to sedimentation ponds
for controlling sediment and erosion in arid and semiarid watersheds, has numerous
environmental and enforcement benefits that are not realized when sediment control is designed
around the implementation of sedimentation ponds alone.  This section presents the distinct
advantages provided by implementation of a fully integrated, site-specific, and appropriate
sediment control BMP system.

4.1    Environmental Benefits

       The capabilities of sediment control BMP systems that are designed to address
site-specific conditions can expedite improved protection and rehabilitation of local natural and
environmental resources that are potentially impacted by mining and reclamation activities.  The
fact that BMP Systems are  specifically designed to minimize disruption of fluvial stability,
minimize mine related disturbances, foster sustainable sediment equilibrium, and minimize
potential for catastrophic release events, makes them appropriate for erosion and sedimentation
control at arid and semiarid mine sites.

4.1.1  Source Control

       Minimizing erosion and sedimentation problems and treating surface runoff at the source
are distinct advantages that BMP systems have over sedimentation pond treatment technology.
Sediment and erosion control BMP Systems are capable of controlling sediment at  its source,
preventing erosion across disturbed areas, and preventing impacts to adjacent undisturbed areas.
Treating erosion and sedimentation at or near the source allows surface water runoff to seek
sediment-content equilibrium throughout the entire watershed. This equilibrium results in the
creation of an acceptable, system-wide dynamic balance between flow volumes and sediment
transport.  Source control is needed to achieve and maintain this balance between sediment
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loading from surface water runoff and long-term erosion control after mining and reclamation
activities have been completed.  To this end, avoiding the construction and subsequent removal
of sedimentation ponds for sediment treatment purposes and establishing a viable BMP system is
paramount to hydrologic system maintenance and rehabilitation.

4.1.2  Minimizes Disturbance to the Hydrologic Balance

       Congress!onally mandated regulatory goals require protection of the waters of the United
States and the avoidance or minimization of disruption to the hydrologic balance where surface
coal mining and reclamation activities are conducted. With the implementation of alternative or
additional BMPs, erosion and sediment control is focused on the source which allows surface
water that does not infiltrate to discharge from mining or non-process areas in a controlled
fashion.  Sediment levels in the runoff are allowed to fluctuate with the erosion potential
conditions in the watershed, and are not artificially reduced by large in-channel structures (i.e.,
sedimentation ponds). This approach to the control and release of surface drainage adjusts the
hydrologic system gradually, allowing it to adjust slowly over time.  This slow adjustment
provides system stability and enables the components of the watershed to effectively interact and
maintain the hydrologic balance. By allowing natural sediment flow through the system, the
fluvial  balance in the watershed benefits through the establishment of natural erosion processes
that will prevail after mining and reclamation activities have ceased.

       Exposing the down-drainage system to sudden flushes of drainage following removal of
flow restricting or constricting structures is avoided. Sudden flood events can be very disruptive
to channel morphology. Seasoning channels with a range of flows over a period of time,  and
avoiding flash flood events or extended periods of water unavailability, facilitates reclamation.
Problem areas associated with various flow volumes can be identified and corrected. Channel
and hydrologic rehabilitation is nurtured for a period of several years under realistic and natural
post-mining flow conditions.  The net result can be improved and reclaimed areas with increased
hydrologic stability and nominal disruption to undisturbed lands adjacent to or downstream from
the affected areas.

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4.1.3  Maintains Natural Sediment Yield

       Surface water drainage with sediment concentrations approximating background levels
avoids the accelerated erosion that is associated with and frequently occurs immediately
downstream from points where low sediment content waters are discharged (Western Coal
Mining Work Group, 1999a).  Accelerated erosion is disruptive to the existing down-drainage
hydrologic balance. In its more dramatic visible forms, accelerated erosion manifests itself in
head-cutting, increased scouring (channel degradation), mass caving, and bank failures in
receiving channels.  In severe cases, this type of erosion may affect tributaries throughout a
portion of or an entire watershed. Establishing sediment yields that approximate natural levels
for the prevailing environmental and hydrologic conditions increases the rehabilitation of
watershed characteristics and provides for increased channel stability.

       Water released from sedimentation ponds contains low concentrations of sediment and
usually occurs in flow volumes significantly less than flow volumes that occurred prior to
mining. When discharges from a sedimentation pond occur, the essentially sediment-free water
begins to immediately entrain sediment from the fluvial  system below the pond.  The small
discharge volumes typically do not have the capacity to transport large amounts of sediment
immediately below the pond, but the discharge can have the potential to accelerate erosion and
degrade the stream channel immediately downstream from the sedimentation pond (Western
Coal Mining Work Group, 1999a).  Due to the cumulative nature of this erosion, it can become
visibly apparent during the Phase II reclamation liability and bonding period (i.e., 10+ years).

       An additional receiving channel impact may occur due to the alteration of sediment
concentration. A lowering or a raising of sediment concentration in drainage from the non-
process area watershed can trigger degradation or aggradation of the receiving channel,
respectively.  Degradation is possible when sediment concentration is lowered and additional
sediment is entrained by the flow event. Conversely, if drainage from the undisturbed
watersheds below the sedimentation pond is higher in sediment concentration, the reduction in
lower sediment concentration flow from the non-process area watershed may trigger aggradation

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of the receiving channel.  This decrease in entrainment capacity and flow can result in increased
sediment.

       Implementation of sediment control BMPs in addition, or as an alternative, to
sedimentation ponds, provides an advantage in allowing drainage to entrain and carry a sediment
load that approaches its energy capacity to do so and that is not artificially adjusted by an
in-stream structure (sedimentation pond) before being released. The result is the prevention of
severe erosion and instability problems directly downstream.

4.1.4  Minimizes Surface Disturbance

       The appropriate application of alternative sediment and erosion control BMPs can avoid
a significant amount of unnecessary surface disturbance on western mine lands. The amount of
land that must be disturbed for construction of sedimentation ponds varies based on site specific
environmental conditions. For example, the number of acres of surface land disturbance
resulting from the use of sedimentation ponds at four coal mine sites in the arid western coal
region are presented in Table 3a, Section 3.2.1. The four mine operations vary significantly in
their use of ponds, from 14 to 149 total ponds that disturb from 36 to 540 acres. The use of BMP
systems would avoid the disturbance of these additional acres.

       Under Wyoming's Guideline No. 15, the Jim Bridger Mine uses alternative sediment
control BMPs (e.g., berms, diversion ditches, and small catchments) to manage drainage from
reclaimed areas and has only disturbed 3.9 acres (Western Coal Mining Work Group, 1999b).
The Jim Bridger mine estimates that an additional 200 acres would be disturbed if sedimentation
ponds were used to manage drainage at this site (Western Coal Mining Work Group, 1999a).
The reduction in surface disturbance that may be expected by implementation of sediment
control BMPs as an alternative to sedimentation ponds is significant.
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4.1.5  Encourages Vegetation

       A BMP system approach to erosion and sediment control maximizes the land's ability to
harvest or use precipitation which is key to the success of vegetation in the arid and semiarid
western United States.  Sediment control has historically focused primarily on the capture of
surface water runoff in sedimentation ponds located on the bottom periphery of the disturbed
area.  Surface water runoff captured by sedimentation ponds in the arid and semiarid regions is
typically allowed to evaporate, and is not made available for vegetative growth or soil
conditioning. Sediment control BMP plans encourage the infiltration and retention of
precipitation in the soil where it benefits microbial activity and plant growth. These BMP plans
are designed to maximize the availability of limited precipitation for improving soil and
enhancing vegetation and are critical to the growth and establishment of vegetation and the
development of plant communities.  Even small increases in plant cover and associated root mass
can have significant impacts on the stability of reclamation surfaces by reducing flow velocity,
increasing soil cohesiveness, and promoting biological diversity.

4.1.6  Improves Soil and Promotes Soil Conservation

       The characteristics of soil are key to successful reclamation.  Water management and soil
improvement practices that are inherent to sediment control BMPs can effectively improve soil
moisture availability.  Soil characteristics that are critical to the growth and establishment of
vegetation can be readily influenced by these BMPs both temporarily and permanently.  BMP
systems promote water infiltration and availability, which increase incorporation of organic
materials capable of improving soil structure, nutrient retention and  availability, water
infiltration and  harvesting, and long-term plant production and diversity.

       Western topsoils are generally poorly developed and tend to  be characteristically poor in
nutrients (Western Coal Mining Work Group, 1999a).  Ensuring that this valuable resource is
conserved and even improved during reclamation is an important concern. Implementation of
appropriate sediment control BMPs can be expected to conserve and protect this resource by

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controlling overland flow and its associated erosion force, limiting slope lengths, increasing
surface roughness, harvesting precipitation, increasing moisture content, promoting vegetation
diversity, increasing organic matter, improving soil texture, and fostering soil formation
processes.  These factors combine to result in improvements to soil characteristics that promote
and encourage stability, soil biota  content, cohesiveness, and plant growth. Increases in soil
biota and above ground vegetation in turn promote soil formation and stability.

4.1.7 Addresses Site-Specific Environmental Conditions

       The design of sedimentation control plans incorporating appropriate BMPs allows for
sediment control on a site-specific basis, according to a site's environmental conditions and
requirements.  Implementation of BMPs that are designed to address specific sedimentation and
erosion concerns, background sediment levels, and hydrologic conditions of a particular site,
allows more appropriate, performance-based sediment criteria to be developed prior to issuance
of permits. Implementation of site-specific, comprehensive sediment and erosion control BMP
plans also allows for consideration of the long-term effects of mining and reclamation operations
and avoids the shock that can be experienced by these watersheds from the implementation and
subsequent removal of water impounding structures (i.e., sedimentation ponds).

4.1.8 Stabilizes Lan dforms

       Topography plays a key role in the long-term surface stability of arid and semiarid non-
process areas.  The primary goal in designing, constructing, and implementing sediment control
BMPs that will determine post-mining topography is to achieve a stable landform.  An
appropriate and natural topography created by implementation of BMP plans that consider
site-specific drainage patterns is essential to minimizing erosion rates and encouraging the
growth of vegetation.

      BMPs that are implemented to provide appropriate topography increase channel stability,
improve soil moisture availability, foster the creation of shallow perched water tables, encourage

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increased infiltration of precipitation and drainage into ground water resources and decrease soil
erosion. All of these functions allow the establishment of vegetation within the reconstructed
channels where little or no vegetation existed prior to mining and reclamation operations.

4.1.9  Minimizes Disruptions to Flow Regime and Evapotranspiration Losses

       Sedimentation ponds have significant potential for removing runoff from the hydrologic
system, and precluding potential down-drainage uses. With the implementation of alternative
sediment control BMPs, drainage is allowed to flow relatively unimpeded. As a result of the
appropriate implementation of these systems, impacts to downstream water users and to
intermittent or perennial water resources, are minimized or avoided. In addition,  the long-term
flow pattern is established early in the reclamation process and sudden impacts to stream
morphology and  flow regime experienced after the removal of a sedimentation pond at Phase II
bond release can be prevented. Disruption of the prevailing hydrologic balance in arid and
semiarid regions can be expected to be much greater when  the use of sedimentation ponds is
predominant, than when BMPs are used to simulate pre-mining, undisturbed conditions.

       BMP systems also avoid the unnecessary impounding of water and associated
evaporation losses.  Losses from ponds can be significant in the arid and semiarid west where
evaporation rates are characteristically much higher than the annual precipitation (Western Coal
Mining Work Group, 1999a).  Implementation of sediment control BMP plans also serves to
increase the availability of surface and ground water, because water loss is avoided and runoff is
allowed to flow naturally  and recharge local downstream resources.
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4.2    Implementation and Enforcement Benefits

4.2.1  Implements Existing Requirements

       The Surface Mining Control and Reclamation Act already institutes specific requirements
for surface coal mining and reclamation operations to achieve acceptable reclamation standards.
These performance standards include successful revegetation, approved post-mining land use,
stabilizing and protecting all surface areas to effectively control erosion, and minimizing
disturbance to the prevailing hydrologic balance while taking into consideration the physical,
climatological, and other characteristics of the site. SMCRA's performance standards require
establishment of an effective, permanent vegetative cover that is at least equal in extent to the
natural vegetation or to that necessary to achieve the approved post-mining land use.

       Implementation of a sediment and erosion control BMP plan designed to address
site-specific sedimentation issues incorporates and complies with all requirements under
SMCRA, without precluding consideration for local hydrologic balance.

4.2.2  Improves Monitoring and Inspection  Capability

       Under the existing effluent guidelines, a mine is required to monitor point source
discharges to demonstrate that Settleable Solids (SS) are equal to or less than 0.5 mL/L when
released from reclaimed areas.  To meet Phase II bond release requirements, the inflow into
sedimentation ponds must be equal to or better than background and meet all applicable federal,
state, local and tribal laws and regulatory requirements.  When these requirements are met, the
operator is eligible to apply for a Phase II bond release for the reclaimed area and terminate the
existing guideline monitoring obligation. With the implementation of alternative  or additional
sediment control BMPs, inspection and enforcement compliance monitoring would be improved
dramatically. It would no longer be necessary to wait for a precipitation event to obtain samples
to determine compliance.  Alternative sediment control BMPs would allow Phase II bond release
inspection and compliance evaluations to proceed independently of the season of the year or

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storm events and on a more frequent basis. The BMP approach uses the inspection of BMP
design, construction, maintenance and operation to demonstrate compliance.

4.2.3 Provides Control and Treatment Flexibility

       Sediment control BMP plans have been and are being successfully implemented.  These
BMP plans are highly adaptable to nearly all erosion and sedimentation control situations.  This
means that each site's unique and diverse environmental conditions may be considered and
addressed through the implementation of site-specific BMP plans that can be designed and
adjusted to achieve a variety of prioritized goals best suited to the needs of a particular location.
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Section 5.0      Case Studies

       The Western Coal Mining Work Group (WCMWG) submitted data and information for
five case studies demonstrating that computer models can be used to 1) predict mine site
hydrology and sedimentology and 2) design and select alternative sediment controls to control
hydrology and sedimentology at coal mine sites in the arid/semiarid western coal mining region.
The data and information submitted by WCMWG are summarized in the following five case
studies.

       •       Case Study 1 - Compares the performance, cost, and benefits of a model mine
              located in the Desert Southwest region using sedimentation pond systems versus
              alternate sediment  control measures;

              Case Study 2 - Is a follow-up study to Case Study 1 comparing the performance,
              cost, and benefits of model mines located in the Intermountain and Northern
              Plains regions using sedimentation pond systems versus alternate sediment
              control measures;

              Case Study 3 - Contains surface water runoff modeling and performance-cost-
              benefit information supporting the addition of lands affected by certain pre-
              mining activities.

       •       Case Study 4 - Demonstrates that since 1984, the Jim Bridger Mine, located in
              southwestern Wyoming, has successfully used alternate sediment control
              measures, in addition to several sedimentation ponds, to treat disturbed area
              runoff to prevent degradation of local stream water quality.

       •       Case Study 5 - The study evaluated available computer models for prediction of
              watershed runoff and sediment yield for selection of a model  that best represents
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             these processes at mine sites in semiarid regions.

5.1    Case Study 1 (Western Coal Mining Work Group, 1999c)

       The National Mining Association (NMA), as part of the WCMWG, conducted studies
comparing the performance, costs, and benefits of model mines located in the Desert Southwest
(Case Study 1), Intermountain (Case Study 2), and Northern Plains (Case Study 2) coal regions.
The studies compared results under conditions designed to meet numeric limits with conditions
designed for use of alternative sediment control to maintain background sediment yield
(WCMWG, 1999c). This section discusses the results of NMA's Desert Southwest model mine
study.

       A representative model mine located in the arid/semiarid southwestern United States was
developed for the comparison, including contour maps and corresponding hydrologic and soil
databases typical of desert southwest mines.  Original and approximate topography were used to
model surface drainage, sediment yield, and soil loss rates from the affected watersheds.  Results
from RUSLE and SEDCAD modeling were generated for the following three scenarios:

       1)     Pre-mining Undisturbed Watershed - Modeling of the area prior to any surface
             preparation, surface disturbance, or mining activities was conducted to
             characterize background water quality, soil loss rates, and sediment yield. Data
             were used to establish background standards for BMP system control;

       2)     Post-mining Reclaimed:  Numeric Limitations - A sedimentation pond-focused
             treatment system was modeled that meets 0.5 ml/L settleable solids (SS) at the
             perimeter outfalls.

       3)     Post-mining Reclaimed:  Sediment  Control BMPs - A BMP system focusing on
             the use of alternate sediment controls was modeled to provide erosion and
             sediment control for reclaimed lands seeking to approximate undisturbed

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              background surface drainage volumes and peaks, total settleable solids (TSS) and
              SS concentrations, soil loss rates, and sediment yields.

       Characteristics of the representative model mine area and information used to perform
performance and cost evaluations are presented in Table 5a.
Table 5a:     Representative Mine Characteristics and Model Input Information
                    Parameter
Input information
Total Acres
Actual Disturbed Acres
Affected Acres
Unaffected Acres
Storm Event
Rainfall
Soil Type
Sediment Control BMPs
Number of Sedimentation Ponds
Types of Surface Conditions
Computer Model Input Information
(RUSLE)
1,188
381.8
616.7
571.3
10 year -24 hour
1.8 inches
Sandy clay loam, Loamy sand
Manipulation of topography, gradient bench
terraces, terrace drains, contour furrows,
reclaimed channels, diversion ditches,
establishment of permanent vegetation,
mulching and detention basins.
3, in series
Undisturbed; Spoil, backfilled and graded,
topdressed, straw mulched and seeded;
Revegetated, 1-3 years
Revegetated, 4-8 years
Rainfall amount, intensity, frequency and
duration; soil moisture conditions, soil types,
susceptibility to erosion, eroded particle size
distributions, infiltration rates, and soil
permeability; vegetative ground cover and
evapotranspiration rates
       The non-process area within the representative model mine contained the following
surface conditions: areas containing spoil outslopes and rough and final backfilling and grading;
areas where soil resources are being replaced (including topdressing, contour furrowing,
mulching, and seeding); and areas with 1-3 years of vegetative growth, or with 4-8 years of more
permanent growth.
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       Non-process area surface conditions also included a final pit undergoing reclamation
with the potential for non-process mine drainage to run off the site.  This configuration normally
represents peak sediment yield potential for a reclaimed area during the mining and reclamation
processes. The non-process area was positioned within a portion of the watershed, so that
drainage from both the non-process area and the adjacent undisturbed lands were considered in
choosing and developing sediment control strategies.


       The alternate sediment control BMPs used during reclamation were:
             Manipulation of topography to develop more stable slopes
       •      Earthen terraces and berms
             Terrace drains
             Contour furrows
       •      Diversion ditches
             Surface roughening/land imprinting
       •      Sediment detention basins
       •      Revegetation

       Reclaimed area topography and the extent of area disturbance were held constant in
modeling both reclamation sediment control scenarios. Holding these inputs constant enabled
and facilitated the analysis and comparison of model results for soil loss, surface drainage rates,
surface drainage volumes, and BMP performance.


5.1.1  Modeling Results


       The modeling approach used for this study is shown in Figure 5a. The RUSLE 1.06 and
SEDCAD 4.0 models were used to estimate values that characterize site hydrology and
sedimentology.
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Figure 5a:    Mine Model Approach: A Method for Evaluating Erosion and Sediment
              INPUTS
  Mine Site Environmental Parameters
  Precipitation-Storm Duration and Intensity
  Soil Characteristics-Texture. Erodibilitv
  Antecedent Moisture Content, and
  Rate
  Vegetation-Effective Ground Cover and
  Use/Crop Management
  Channel-Cross Section
  Configuration and Area, Slope, Length
  Gradient, Bed Material Particle Size
  and Relative Percentages, Watershed
  Acreage, and Subwatersheds


  Mining Operation Characteristics
  Pit Dimensions-Dragline.
  Annual Production, Depth to Seams,
  Interburdens
  Prestripping Dimensions-Dragline. Truck
  Shovel, and Soil Salvage


  Sediment Control Options
  Managerial-BMP System
  Operational-Construction and
  Structure Ho pog ra ph i c Manipulation,
  Stabilization,  Flow Modification
  Soil Conservation, and Road Drainage	
                            MINE MODELING
                            Watershed and Mine
                               Modeling Tools
                                 SEDCAD 4.0
                                 RUSLE1.06

                            Pond & Alternate
                            Control Method Unit
                            Costs

                            Environmental Baseline
                            Information
       OUTPUTS
Performance
Sediment Control

Costs
Selected Sediment
Control Options

Benefit
Environmental Benefits &
 Impacts
               Control Options (WCMWG, 1999c)
5.1.1.1
RUSLE 1.06
       Annual average soil loss was predicted for two scenarios with the help of RUSLE version

1.06. The two scenarios were for pre-mining (undisturbed) conditions and for post-mining

(reclaimed with BMPs). The type of input information for the modeling effort is listed in Table
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5b. Information input values were based on vegetation, soils, and surface configurations
obtained from case study mines and mine permits. Representative data were entered into the
RUSLE program to generate sediment loss values. RUSLE input and output data are presented
in Appendix D, Tables D-l through D-5.


       For pre-mining, undisturbed conditions, the predicted, weighted average annual soil loss
was 4.7 tons/acre/yr.  According to the WCMWG, this is a reasonable value for the arid and
semiarid coal regions (WCMWG, 1999c). The weighted average annual soil loss of the
reclaimed mine lands was 3.0 tons/acre/yr.  Data supporting the weighted average soil loss
estimates are presented in Appendix D, Table D-6.  The soil loss is slightly lower after
reclamation because the BMPs allow for improved infiltration and retention of storm water, and
for the growth and establishment of vegetation. Also, implementation of BMPs results in
landforms that have been reconstructed to facilitate lower erosion rates and enhanced deposition
at down-gradient slope boundaries.


5.1.1.2       SEDCAD 4.0


       All sediment and hydrology model results from the mine prior to mining and from the
mine after reclamation using BMPs to control sediment are similar, whereas the model results for
the area reclaimed to meet numeric effluent limitations (0.5 ml/L SS) are considerably lower
than the pre-mining conditions.  The decrease in  sediment yield and runoff resulting from
compliance with this limit is expected due to the  implementation of sedimentation ponds that
impound runoff. To avoid potential adverse impacts on the hydrologic and sediment balance,
and to maintain the stability of the fluvial system, drainage from the non-process areas should be
as similar to pre-mining drainage as possible.  Based on this standard, implementation of BMPs
would be a preferred option. Sediment loss, soil  loss, and surface runoff model results for
undisturbed conditions, non-process areas with sedimentation ponds, and non-process areas with
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alternative sediment control BMPs are presented in Table 5b.  SEDCAD output for each of the
three scenarios is presented in Appendix D.


5.1.2   Cost


       The WCMWG completed an extensive analysis of costs associated with meeting effluent
limitations using sedimentation ponds and implementing BMPs under a Western Alkaline Coal
Mining subcategory.  Cost estimating criteria for sedimentation ponds and BMPs implemented at
the model mine were collected from approved mine permit applications, developed from mine
records, and estimated using technical resources and industry experience.  These unit cost data
are presented in detail in NMA's Mine Modeling Report (WCMWG, 1999c).


       The model cost assessment was based on capital costs (design, construction, and
removal) and operating costs (inspection, maintenance, and operation) associated with BMPs
used over the anticipated bonding periods. The bond release period for meeting numeric effluent
standards in the arid and semiarid western coal region can be expected to be ten years or longer
(WCMWG,  1999a; Peterson, 1995). With the implementation of alternative sediment control
BMPs, reclaimed areas may be eligible for Phase II bond  release about five years after they have
been successfully revegetated (WCMWG, 1999a).


       Capital and operating reclamation costs, as estimated by the WCMWG, for both the
effluent numeric limitation and the proposed non-numeric option are presented in Table 5c. The
present value of the reclamation costs over the ten year period (discounting at seven percent) is
$1,700,000 for the existing guideline and $1,028,000 for the proposed subcategory, or a present
value total savings of $672,000 over ten years.  This represents a 39 percent overall reduction in
costs or $1,764 in savings per disturbed acre.  The annualized savings is $95,000 (annualized at
seven percent) or $251 annualized savings per acre for the 381 reclaimed acres.


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Table 5b:     Comparison of Hydrology and Sedimentology Results (modified from
               WCMWG, 1999c)

Pre-Mining
Undisturbed
Conditions
Result
Reclaimed to Meet
Numeric
Limitations12
Result
% Change
from
Pre-mining
Reclaimed Under
Alternate Sediment
Control Measures3
Result
% Change
from
Pre-mining
RUSLE (V 1.06) Modeling Results
Soil Loss (tons/acre/year)
(Weighted Average)
4.7
NM4
N/A
3.0
-36
SEDCAD (V 4.0) Modeling Results
Peak Discharge (cfs)
(10 year, 24-hour storm event)
Total Runoff Volume (acre-feet)
(10 year, 24-hour storm event)
Sediment (tons)
(10 year, 24-hour storm event)
Sediment (tons/acre)
(10 year, 24-hour storm event)
Peak Sediment (mg/L)
(10 year, 24-hour storm event)
Peak Settleable Solids (ml/L)
(10 year, 24-hour storm)
Settleable Solids (ml/L)
(24-hr Volume Weighted)
(10 year, 24-hour storm)
Sediment Yield (acre-feet/year)
(Average Annual)
679.09
80.01
7,004.2
5.9
155,091
38.22
17.89
8.3
44.79
48.83
666.1
0.6
28,235
0.00
0.00
o5
-93
-39
-90
-90
-82
-100
-100
-100
601.89
72.93
5,611.1
4.7
114,800
25.86
13.96
6.7
-11
-9
-20
-20
-26
-32
-22
-19
1 Sediment was controlled with sedimentation ponds.
2 Assumes ponds are filled to design storage capacity with 3 years of sediment runoff.
3 Sediment was controlled by alternative sediment control BMPs.
4 Not measured.
5 Assumes no sediment is stored in the ponds, and 3 years of annual sediment runoff volume is available. SEDCAD
   4.0 uses a subroutine that implements a method similar to RUSLE to determine average annual sediment yield.
   SEDCAD sedimentology input values were taken directly from the RUSLE version 1.06 analysis.
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 Table 5c:       Cost of Compliance with Numeric Limitations vs. Cost to Implement Alternative
                Sediment Control BMPs (adapted and revised from WCMWG, 1999c)

Numeric Effluent Limits
Year
Capital
1 $975,435
2
3
4
5
6
7
8
9
10
2,720
0
0
0
0
0
0
0
171,607
Total (not $1,149,761
discounted)
Operating
$15,384
142,804
190,181
88,956
26,231
161,999
15,269
15,269
133,377
15,269
$804,739
Annualized @ 7% over 10
years
Annualized Saving
Annualized Saving
?s
>s per Reclamation Acre2
Alternate Sediment Control BMPs
Total Present Capital Operating Total
Value1
$990,819 $990,819 $760,816 $3,300 $764,116
145,524
190,181
88,956
26,231
161,999
15,269
15,269
133,377
186,876
$1,954,501 $1
136,004 43,577 103,368 146,944
166,112 0 59,876 59,876
72,615 0 77,895 77,895
20,011 0 14,147 14,147
115,503
10,175
9,509
77,626
101,648
,700,021 $804,393 $258,586 $1,062,979
$242,045
$95,663
$251
Present Value Total Savings
Present Value Total Savings per Acre2
Present
Value1
$764,116
137,332
52,298
63,586
10,793
-
-
-
-
-
$1,028,124
$146,382
$671,897
$1,764
 Costs expressed in 1998 Dollars
 1 Discount Rate: 0.07
 2 Based on 381 disturbed acres
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5.2    Case Study 2 (Western Coal Mining Work Group, 2000a)

       To complement the results of the model mine study presented in Section 5.1 (Case Study
1), NMA also conducted this follow-up study comparing the performance, cost, and benefits of
model mines located in both the Intermountain and Northern Plains coal regions to meet
numeric effluent limitations versus the use of alternative sediment control BMPs (WCMWG,
2000a).

       Two models were developed using representative non-process areas within the
Intermountain and Northern Plains regions in the western United States.  These models were
based on site-specific hydrology and soil databases for the Intermountain and Northern Plains
coal regions.  Site-specific input variables include
       •      Rainfall amount
       •      Rainfall intensity
       •      Rainfall frequency
       •      Rainfall duration
       •      Antecedent soil conditions
             Soil types
             Susceptibility  to erosion
             Eroded particle size distribution
       •      Infiltration rates
       •      Soil permeability
       •      Vegetative ground cover

Other variables  such as topography, disturbance area (disturbance footprint), and non-process
areas (e.g., backfilling and grading area, surface roughening area, revegetation area, etc.) were
standardized and held constant to aid in the comparison of the case studies from the different
regions.

       For both the Intermountain and Northern Plains examples, modeling was performed for
three scenarios:
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       1)     Pre-mining background - A characterization prior to surface disturbance by
              mining and reclamation activities that is used to establish site-specific sediment
              control standards for the proposed BMP treatment system;

       2)     Numeric Limitation Requirements  - Modeling and design of a sediment control
              system that meets numeric limitations for runoff from non-process areas; and

       3)     Sediment Control BMPs - Modeling and design of a BMP alternate sediment
              control system that meets background levels for runoff from non-process areas.

       Modeling prior to surface disturbance by mining was conducted to characterize pre-
mining background water quality, soil loss rates, and sediment yield. The modeled values serve
as a benchmark, establishing standards for the sediment control measures.

       Non-process areas also were modeled to meet numeric limitations using typical surface
water runoff control and treatment methods for the model's standardized disturbance footprint
for both Intermountain and Northern Plains environmental conditions.  Typical surface water
runoff treatment systems (sedimentation ponds) were designed to meet the discharge
requirements for numeric limitations for surface water runoff (0.5 ml/L settleable solids).

       A third modeling scenario using the standardized disturbance footprint was used to meet
background sediment yields. This scenario emphasized implementation of an alternate erosion
and sediment control system to meet pre-mining watershed runoff conditions and prevent the
contribution of additional sediment to the receiving stream.

5.2.1  Modeling Results

       Average annual erosion quantities were predicted based on the RUSLE model version
1.06.  Input parameter values for the modeling effort were based on vegetation, soils, and surface
configurations obtained from existing case study mines and mine permits. RUSLE variables

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were input to SEDCAD 4.0 to model watershed sedimentology.  Since the analysis of a 10-year,
24-hour design storm is typically required, all three scenarios were assessed using the design
storm in the SEDCAD 4.0 model. Modeling erosion and sediment controls for non-process areas
under numeric and non-numeric (sediment control BMPs) requirements produced the hydrology
and sedimentology data for the Intermountain and Northern Plains non-process areas as shown
in Tables 5d and 5e, respectively.

       For the Intermountain reclaimed area, the sediment control BMPs reduced peak
discharge by approximately 38% below background levels, while the treatment designed to meet
numeric limitations reduced the peak discharge by 96% below background levels. For the
Northern Plains reclaimed area, the BMP system reduced peak discharge by approximately 33%
below background levels, while the treatment to meet numeric limitations reduced the peak
discharge 97% below background levels.  For both areas modeled, the sediment control system
mimics the background peak  discharge levels more closely.
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Table 5d:
Comparison of Hydrology and Sedimentology Results for the Intermountain
Reclamation Model (Western Coal Mining Work Group, 2000a)

Pre-mining
Undisturbed
Conditions
Result
Reclaimed to Meet
Numeric Limitations
Result
% Change
from
Pre-mining
Reclaimed Under
Alternate Sediment
Control Procedures
Result
% Change
from
Pre-mining
Intermountain Non-process Area
Sediment Production (tons)
Peak Discharge (cfs)
(10 year, 24-hr storm event)
Total Runoff Volume (acre -ft)
(10 year, 24-hr storm event)
Settleable Solids (ml/L)
(24-hr Volume Weighted)
(10 year, 24-hr storm event)
Peak Settleable Solids (ml/L)
Peak Sediment (mg/L)
(10 year, 24-hr storm event)
1,030
160
27
18
58
100,800
O1
62
223
0
O4
O5
-100
-96
-19
-100
-100
-100
660
100
21
15
48
82,400
-36
-38
-22
-17
-17
-18
'Most sediment is trapped in the sediment pond. Minimum amount of sediment released during discharge.
2Assumes 100% of runoff volume is discharged from pond over a 2-day period.
3Assumes 100% of runoff volume is treated and discharged. This is conservative as some water will be lost to
infiltration, minimum pool ponding, and evaporation.
4Containment in pond with slow discharge rate will remove all settleable solids.
'Containment in pond with slow discharge rate will remove most suspended sediment.
       For the Intermountain reclaimed area, the proposed sediment control system achieved
peak sediment concentrations that were approximately 18% lower than pre-mining background
levels, while the treatment designed to meet numeric limitations had peak sediment
concentrations that were near zero.  This is a direct result of capturing almost 100% of the
sediment in sedimentation ponds.  The BMP treatment system also achieved superior results in
the Northern Plains example, with peak sediment concentrations that were approximately 14%
lower than pre-mining background levels, while the current subcategory treatment system again
had peak sediment concentrations that were near zero.
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Table 5e:
Comparison of Hydrology and Sedimentology Results for the Northern
Plains Reclamation Model (Western Coal Mining Work Group, 2000a)

Pre-mining
Undisturbed
Conditions
Result
Reclaimed to Meet
Numeric Limitations
Result
% Change
from
Pre-mining
Reclaimed Under
Alternate Sediment
Control Procedures
Result
% Change
from
Pre-mining
ntermountain Non-process Area
Sediment Production (tons)
Peak Discharge (cfs)
10 year, 24-hr storm event)
Total Runoff Volume (acre -ft)
10 year, 24-hr storm event)
Settleable Solids (ml/L)
(24-hr Volume Weighted)
10 year, 24-hr storm event)
Peak Settleable Solids (ml/L)
Peak Sediment (mg/L)
10 year, 24-hr storm event)
850
250
42
10
30
52,500
O1
82
313
0
O4
O5
-100
-97
-26
-100
-100
-100
520
167
30
8
26
45,100
-39
-33
-29
-13
-13
-14
'Most sediment is trapped in the sediment pond. Minimum amount of sediment released during discharge.
2Assumes 100% of runoff volume is discharged from pond over a 2-day period.
3 Assumes 100% of runoff volume into pond is treated and discharged. This is conservative as some water will be
lost to infiltration, minimum pool ponding, and evaporation.
4Containment in pond with slow discharge rate will remove all settleable solids.
'Containment in pond with slow discharge rate will remove most suspended sediment.
       In the Intermountain example, sediment yield resulting from the BMP treatment system
more closely approximated background at 660 tons (a reduction of 370 tons from background)
versus the treatment to meet numeric limits which resulted in a sediment yield of 0 tons (a
reduction of 1,030 tons from background). In the Northern Plains example, sediment delivery
resulting from the BMP system more closely approximated background at 520 tons (a reduction
of 330 tons from background) versus treatment to numeric limits that resulted in a yield of 0 tons
(a reduction of 850 tons).  Settleable solids were released from the Intermountain BMP system at
a concentration of 48 ml/L (17% below background levels), while treatment to numeric limits
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reduced SS by almost 100%. For the Northern Plains example, SS were released from the BMP
treatment system at a concentration of 26 ml/L (13% below background levels), while treatment
to numeric limits reduced SS by almost 100%. These results demonstrate that BMP treatment
systems are capable of and better suited to release runoff that more closely approximates pre-
mining watershed conditions. Using BMP sediment control systems to treat runoff from non-
process areas can be expected to significantly improve protection of hydrologic and fluvial
balances in watersheds affected by mining in western arid and semiarid alkaline environments.

5.2.2  Costs

       Detailed capital and operating costs associated with the sediment control options
specified for both the Intermountain and Northern Plains model mines were developed for 1)
meeting numeric limitations, and 2) implementing sediment control measures to mimic
background conditions. As was done for the Desert Southwest model in Case Study 1, capital
costs include design,  construction, and removal activities.  Operating costs include inspection,
maintenance, and  operating activities.  The costs were developed for anticipated bonding periods
of five years and ten years.  Design criteria used as the basis of costs for both the Intermountain
and Northern Plains models are summarized in Table 5f.
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Table 5f- Model Mine Design Criteria
Sediment Control
Technology
Sedimentation Pond (n=l)
Spillway for
Sedimentation
Small Depressions (n=3)
Gradient Bench Terraces
Terrace Drains
Channel Stabilization Rip
Rap
Diversion Channel #1
Diversion Channel #2
Diversion Channel #3
Revegetation
Surface Roughening
Northern Plains Model Mine
Numeric Limits
Quantity
31
200
-
27,637
8,298
400
3,600
3,650
880
393.0
393.0
Unit
ac-ft
linear
feet
-
linear
feet
linear
feet
linear
feet
linear
feet
linear
feet
linear
feet
Acres
Acres
Alternate
Sediment Control
Quantity
-
-
<1
27,637
8,298
"
3,600
3,650
880
381.2
381.2
Unit
-
-
ac-ft
linear
feet
linear
feet
-
linear
feet
linear
feet
linear
feet
Acres
Acres
Intel Mountain Model Mine
Numeric Limits
Quantity
22
175
-
27,637
8,298
400
3,600
3,650
880
392.4
392.4
Unit
ac-ft
linear
feet
-
linear
feet
linear
feet
linear
feet
linear
feet
linear
feet
linear
feet
Acres
Acres
Alternate
Sediment Control
Quantity
-
-
<1
27,637
8,298
"
3,600
3,650
880
381.2
381.2
Unit
-
-
ac-ft
linear
feet
linear
feet
-
linear
feet
linear
feet
linear
feet
Acres
Acres
Comments

2: 1 side slopes with 50-ft bottom width; Allowed 1.5 ft for rip rap depth, 1 ft
freeboard, depth Intermountain=1.35, Northern Plains=1.53

Intermountain=1.8, Northern Plains=2-ft depth with 3:1 and 10:1 cut and fill slopes,
25% of land requires terracing @ 150 ft intervals.
Cross-section is V-shaped 2.5' depth; side slopes 3h: Iv; 1.5 ft excavation depth for
riprap liner, 8-ft bottom width
Used to stabilize reconstructed drainage channel when sediment pond is removed Yr
10, 8 structures 50-ft in length will be placed at intervals for channel gradient and X-
section control, 3: 1 side slopes, channel depth = 4.5 ft.
Trapezoidal X-Section, 8 ft bottom, 3:1 side slope, Northern Plains 2.4ft deep,
Intermountain= 2.0 ft deep
Trapezoidal X-Section, 8 ft bottom, 3:1 side slope, Northern Plains 2.4ft deep,
Intermountain= 2.0 ft deep
Trapezoidal X-Section, 8 ft bottom, 3:1 side slope, Northern Plains 2.4ft deep,
Intermountain= 2.0 ft deep
Includes seedbed preparations, seeding, mulching and fertilizing
Including ripping, contour furrows and land imprinting
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       The sediment control structures and BMPs used for the Intermountain and Northern
Plains models are as follows:

             Models designed to meet numeric limitations use a single sedimentation pond.
             Runoff from undisturbed conditions entering the main drainage in the vicinity of
             the sedimentation pond is conveyed around each side of the pond using grass
             lined diversions.  Some mulching and limited surface roughening has been
             applied.  The reclaimed land surface has been recontoured with terraces to reduce
             slope lengths and steepness. The reclaimed area for both Intermountain and
             Northern Plains scenarios is approximately 381.2 acres, with additional acres of
             disturbance for the sedimentation pond and diversions of 11.2 acres in the
             Intermountain scenario and 11.8 acres in the Northern Plains scenario.

       •      Models designed to approximate or improve background conditions use a BMP
             system instead of a sedimentation pond to treat surface runoff. The BMP system
             includes the same surface topography manipulation as applied to meet numeric
             limitations, including terraces and recontouring to reduce slope lengths and
             steepness.  No diversions or sedimentation ponds were used.  More extensive
             mulching and surface roughening were applied, including deeper contour furrows,
             land imprinting and the use of surface depressions. Since these practices typically
             result in better water harvesting and a subsequent increase in vegetation density,
             credit was  taken for the vegetation density increase on older reclaimed areas.

       Capital and operating reclamation costs for meeting numeric limitations  and for
implementing alternative  sediment control measures for the Intermountain model  mine are
presented in Table 5g (WCMWG, 2001).  The present values of the total reclamation costs over
the ten year period (discounting at seven percent) are $844,132 to meet numeric limitations and
$645,266 to  implement alternative sediment control measures. This represents a present value
total savings of $198,866  over ten years, a 24 percent overall reduction in costs  or $522 in
savings per disturbed acre when alternate sediment control measures are used.  The annualized

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savings is $28,315 (annualized at seven percent) or $74 annualized savings per acre for the 381
reclaimed acres.

       Capital and operating reclamation costs for meeting numeric limits and for implementing
alternative sediment control measures for the Northern Plains mine model are presented in Table
5h. The present values of the total reclamation costs over the ten year period (discounting at
seven percent) are $889,011 to meet numeric limitations and $653,636 to implement alternative
sediment control measures. This represents a present value total savings of $235,375 over ten
years, a 26 percent overall reduction in costs or $618 in savings per disturbed acre when
alternate sediment control measures are used.  The annualized savings is $33,512 (annualized at
seven percent) or $88 annualized savings per acre for the 381 reclaimed acres.
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                                          Development Document - Western Alkaline Coal Mining Subcategory
Table 5g: Cost of Meeting Numeric Limits vs. Cost to Implement Alternative Sediment
Control BMPs for the Intermountain Model Mine (adapted and revised from
WCMWG, 2001)
Numeric Limitations Alternate Sediment Controls Measures
Year Capital
1 $479,458
2 43,577
3 0
4 0
5 0
6 0
7 0
8 0
9 0
10 134,550
Total (not $657,585
discounted)
Operating
$10,777
65,142
36,230
67,818
45,677
41,310
10,663
10,663
11,698
13,319
$313,296
Annualized @ 7% over 10 years
Annualized Savings
Annualized Savings per Reclamation Acre2
Total Present Capital Operating Total
Value1
$490,235 $490,235 $428,315 $3,677 $431,992
108,718 101,606 43,577 58,065 101,642
36,230 31,645 0 29,142 29,142
67,818 55,360 0 60,808 60,808
45,677 34,847 53,049 3,563 56,612
41,310 29,453
10,663 7,106
10,663 6,641
11,698 6,808
147,869 80,431
$970,881 $844,132 $524,940 $155,255 $680,195
$120,186
$28,3 1 5 Present Value Total Savings
$74 Present Value Total Savings per Acre2
Present
Value1
$431,992
94,993
25,454
49,638
43,189
-
-
-
-
-
$645,266
$91,871
$198,866
$522
 Costs expressed in 1998 Dollars
 1 Discount Rate: 0.07
 2 Based on 381 disturbed acres
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Development Document - Western Alkaline Coal Mining Subcategory
Table 5h
: Cost of Meeting Numeric Limits vs. Cost to Implement Alternative Sediment
Control BMPs for the Northern Plains Model Mine (adapted and revised from
WCMWG, 2001)
Numeric Limitations Alternate Sediment Control Measures
Year
1
2
3
4
5
6
7
8
9
10
Capital Operating
$513,552 $11,682
43,577 66,628
0 37,426
0 68,723
0 46,582
0 42,408
0 11,568
0 11,568
0 12,699
140,054 14,224
Total (not $697,183 $323,508
discounted)
Annualized
Annualized
Annualized
@ 7% over 10 years
Savings
Savings per Reclamation Acre2
Total Present Capital Operating Total
Value1
$525,234 $525,234 $432,631 $3,677 $436,309
110,204 102,995 43,577 58,646 102,223
37,426 32,689 0 29,433 29,433
68,723 56,099 0 60,808 60,808
46,582 35,537 57,317 3,563 60,880
42,408 30,236
11,568 7,709
11,568 7,204
12,699 7,391
154,278 83,917
$1,020,691 $889,011 $533,525 $156,127 $689,651
$126,575
$33,512 Present Value Total Savings
$88 Present Value Total Savings per Acre2
Present
Value1
$436,309
95,536
25,708
49,638
46,445
-
-
-
-
-
$653,636
$93,063
$235,375
$618
 Costs expressed in 1998 Dollars
 'DiscountRate: 0.07
 2 Based on 381 disturbed acres
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                                   Development Document - Western Alkaline Coal Mining Subcategory
5.3    Case Study 3 (Western Coal Mining Work Group, ZOOOb)

       This case study contains surface water runoff modeling and performance-cost-benefit
information regarding alternative sediment control technologies for non-process areas in the
Western Alkaline Coal Mining Subcategory (WCMWG, 2000b).  The areas include:

              Brushing and grubbing - removal or incorporation of woody plant material that
              would interfere with soil salvage operations
              Soil salvage - soil reconstruction materials (soil, subsoil, and neutral dressing),
              and
       •       Soil stockpiling activities  - activities where soil resources are stockpiled for
              future use in soil reconstruction or reclamation

       Land affected by these activities are considered to be appropriate for the implementation
of alternate sediment control technologies when sediment is the only constituent of concern in
non-process surface water runoff.  This case study contains an analysis comparing the predicted
performance-costs-benefits associated with sedimentation pond systems to the use of alternate
BMP sediment controls to minimize impacts to the hydrological and fluvial balance of western
coal mine watersheds.

       Modeling was conducted for a representative mine in the arid/semiarid western United
States using the following three scenarios:

       1)     Pre-mining background - A characterization prior to surface disturbance by
              mining and reclamation activities;

       2)     Numeric Limitations - Modeling and design of a sediment control system that
              meets numeric limitations for runoff from areas where pre-mining activities
              supporting reclamation are being conducted; and
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       3)     Alternate Sediment Control Measures - Modeling and design of a BMP-based
              alternate sediment control system that meets background sediment yield standards
              for runoff from areas where pre-mining activities supporting reclamation are
              conducted.

       Modeling of conditions prior to surface disturbance by mining was conducted to
characterize pre-mining background water quality, soil loss rates, and sediment yield. The
modeled values serve as a benchmark, establishing standards for the alternate sediment control
system.

       Non-process areas were modeled using 1) alternate sediment control measures, and 2) a
treatment system designed to meet a maximum daily TSS concentration of 70 mg/L and a 30-day
average TSS concentration of 35 mg/L.

       NMA developed a third scenario using alternative erosion and sediment control
techniques. The alternate sediment control BMPs used in the modeling effort were:

                    Silt fences
              •      Infiltration berms
              •      Porous rock check dams
              •      Rock diversions
              •      Rotoclearing or chipping

       The same contour mapping and corresponding hydrographic and soils databases that were
developed for Case Study 1  were  used to support modeling of the hydrology  and sedimentology
of a typical watershed in the arid/semiarid western United States.

5.3.1  Modeling Results

       Average annual erosion quantities were predicted based on the RUSLE model version
1.06.  Input parameter values for the modeling effort were based on vegetation, soils, and surface
configurations obtained from existing case study mines and mine permits.  RUSLE variables
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                                   Development Document - Western Alkaline Coal Mining Subcategory
were input to SEDCAD 4.0 to model watershed sedimentology.  Since hydrologic conditions
were also modeled (analysis of a 10-year, 24-hour design storm), all three scenarios were
assessed with SEDCAD 4.0.

       40 CFR Part 434, Subcategory H requires establishment of pre-mining background
watershed conditions, against which the adequacy of the sediment control system is measured.
Use of alternate BMP sediment control systems during mining and reclamation facilitates
deployment of controls designed to mimic site-specific, pre-mining background watershed
conditions. Mine modeling of pre-mining activities supporting reclamation was performed in
order to characterize potential benefits of these systems.

       Modeling erosion and sediment controls for pre-mining activities produced the results
shown in Table 5i.
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Table 5i:
Comparison of Hydrology and Sedimentology Results (Western Coal Mining
Work Group, 2000b)

Total Contributing Area (acre)
Peak Discharge (cfs)
(10 year, 24-hr storm event)
Total Runoff Volume (acre -ft)
(10 year, 24-hr storm event)
Sediment (tons)
(10 year, 24-hr storm event)
Sediment Loss (tons/acre)
Peak Sediment (mg/L)
(10 year, 24-hr storm event)
Peak Settleable Solids (ml/L)
(10 year, 24-hr storm event)
Settleable Solids (ml/L)
(24-hr Volume Weighted)
(10 year, 24-hr storm event)
Pre-mining
Background
Result
291
103
12
1,067
3.7
129,300
58
30
Reclaimed to Meet
Numeric Limits1
Result
266
7
163
0
0
40
0
0
% Change
from
Pre-mining
-9
-93
+33
-100
-100
-100
-100
-100
Reclaimed Under
Alternate Sediment
Control Measures
Result
291
932
18
586
2.0
119,200
24
5
% Change
from
Pre-mining
0
-10
+50
-45
-46
-8
-65
-83
'Assumes pond is filled to design storage capacity with 1 year of transported sediment.
2 Four porous rock check dams were used as BMPs.  SEDCAD 4.0 does not give credit for reduction or attenuation
       in peak flow when using the check dam structure analysis option.  The two upstream check dams (Stru#l
       and Stru#2) were very small and on steep gradients and were modeled as check dams.  The two larger
       dams (Stru#8 and Stru#12) were on flatter gradients and were modeled as ponds to take peak flow
       attenuation into account.
3Sediment pond outflow devices  include a fixed siphon (which was modeled) and a gate pipe with a floating inlet
       designed to remove water from the pond by decanting water from near the pond surface.
       The most important modeling results are for peak discharge and peak sediment

concentration.  The BMP treatment system reduced peak discharge by only 10% below

background levels, while the system for treatment to numeric limitations reduced the peak

discharge by 93% below background levels.
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                                   Development Document - Western Alkaline Coal Mining Subcategory
       Prolonged changes in peak sediment concentrations are capable of disrupting fluvial
balances and introducing degradation or aggradation in the receiving channel.  The proposed
BMP treatment system achieved peak sediment concentrations approximately 8% less than pre-
mining background levels, while the current subcategory treatment system had peak sediment
concentrations that were near zero to comply with the effluent standard of 35/70 mg/L TSS.
This is a direct result of capturing almost 100% of the sediment in the sediment pond.

       Sediment delivery from the BMP treatment sediment control system more closely
approximated background at 2.0 tons (a reduction of 1.7 tons) vs. the treatment system's delivery
of 0 tons (a reduction of 3.7 tons).  Settleable solids levels released from the BMP treatment
system were a little more than half the background conditions, while the treatment system
reduction was almost 100%.

5.3.2  Costs

       An analysis of costs was conducted under both the sediment control system and the
system designed to treat  to numeric limitations. Cost assessment was based on capital costs
(design, construction, and removal) and operating costs (inspection, maintenance, and operation)
associated with the sedimentation pond system and the BMP-based system used over the two-
year development period. These costs were developed for the two-year period of pre-mining
activities supporting reclamation.  A summary of the costs associated with both the current
subcategory and proposed subcategory options are presented in Table 5j.

       The present value of the reclamation costs over the two-year premining period
(discounting at seven percent) is $463,582 for the existing guideline and $202,190 for the
proposed subcategory, or a present value total savings of $261,392 over two years.  This
represents a 56 percent overall reduction in costs, or $2,489 is saving per disturbed acres. The
annualized savings are $135,115 (annualized at seven percent), or $1,287 annualized savings per
acre  for the 105 disturbed acres.
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Development Document - Western Alkaline Coal Mining Subcategory
 Table 5j:      Cost of Sedimentation Pond System vs. Cost to Implement Alternative Sediment
                Controls (adapted and revised from WCMWG, 2000b)
Sedimentation Pond System
Year
1
2
Total (not
discounted)
Annualized @
Capital
$420,512
-
$420,512
Operating
$24,845
19,501
$44,346
Total
$445
19
$464
,357
,501
,858
7% over 2 years
Annualized Savings
Annualized Savings per Reclamation Acre2
Present
Value1
$445
,357
18,225
$463
$239
,582
,629
$135,115
$1,287
Alternate Sediment Control Technologies
Capital
$174
9
$183

Present
Present
,050
,718
,768

Operating
$9,177
10,572
$19,749

Total
$ 83,227
20,290
$203,517

Value Total Savings
Value Total Savings per Acre2
Present
Value1
$183,227
18,963
$202,190
$104,514
$61,392
$2,489
 Costs expressed in 1998 Dollars

 1 Discount Rate: 0.07

 2 Based on 105 disturbed acres.
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                                  Development Document -  Western Alkaline Coal Mining Subcategory
 5.4   Case Study 4 (Bridger Coal Company, Jim Bridger Mine)

       Wyoming Department of Environmental Quality, Land Quality Division Rules and
Regulations, Chapter IV, Section 3g(l) states that exemptions to the use of sedimentation ponds
may be granted where, by the use of alternative sediment control (ASC) measures, mine drainage
will not degrade receiving waters. The Jim Bridger Mine located in southwestern Wyoming, has
successfully used ASC measures, in addition to several sediment ponds, to treat disturbed area
runoff and prevent degradation of local stream water quality since 1984.

       Case Study 4 presents a summary of a Jim Bridger Mine study provided by the Western
Coal Mining Work Group (Bridger Coal Company, 1987). Bridger Coal Company began coal
production in 1974.  The Bridger mine is located in a desert located 28 miles northeast of Rock
Springs in southwest Wyoming. Mean annual precipitation is 6-8 inches, and the mean frost free
period is  100 days. High winds are frequent and evapotranspiration is high.  Some soils and
spoils are saline or sodic.  The local receiving water consists of ephemeral streams.

       An experimental practice for a portion of the mine was initiated in 1983  to test the
effectiveness of alternate sediment control techniques compared to sediment ponds for
preventing additional contributions of sediment to receiving streams. The alternate sediment
control practices became standard in 1987, and are still in use today. The effectiveness of
alternate  sediment control techniques continues to be monitored.

5.4.1  Justification of Alternate Sediment Controls

       Initial water quality data available for receiving streams are presented in Figure 5b.  The
data indicate that undisturbed mine area runoff is high in suspended solids.  Data from single
stage sediment samples show total suspended solids (TSS) concentrations of 110 to 820,000
mg/L for discharges from 1 to 500 cubic feet per second (cfs). The highest values measured by
single stage sediment samples were enriched in coarse sediment by continued circulation during
the runoff event.  However, values of 800,000 mg/L indicate that sediment transport is high.

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Development Document - Western Alkaline Coal Mining Subcategory
1,000
100
t3_
0)
O)
TO
0
(A
Q
10



1
1(
Figure 5b: Initial Receiving Stream TSS Data
A
•
A A ^

• X
A
A
X


i i 	 I i 	 I i W__|__|
DO 1,000 10,000
Total Suspended Solids (mg/L)
A
I


.
* Mddle Headman Wash
• Nine One Half Mne Wash
Gauge
A Ten Mle Draw Trib.
• Nine Mle Wash
X Nine One Half Mle Wash
Above Rt








100,000 1,000,000

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                                   Development Document - Western Alkaline Coal Mining Subcategory
       Logistical concerns regarding sediment ponds were important in the decision to
implement alternate sediment control techniques. The extensive mining area and the drainage
density would necessitate approximately 200 ponds to control all mining disturbed runoff over
the life of the mine. This would entail disturbing over 400 additional acres. Such land
disturbance is essentially eliminated by use of alternate sediment control techniques.

       The benefits of the use of alternate sediment controls instead of sediment ponds are:

             •      Channel degradation below dams, produced by the discharge of
                    unnaturally clear and erosive water, is precluded;
             •      Additional disturbance due to dam and pond construction is avoided; and
             •      With the elimination of impoundment storage time, seepage, and
                    evaporation, there is less disruption of natural stream flows.

5.4.2   Description of Alternate Sediment Control Techniques

       Several techniques are used by the Bridger Coal Company to limit sediment discharge
from mined land to background levels (Hargis, 1995). Most of these techniques are appropriate
for small drainage areas. Drainage from larger areas can be diverted to the pit floor where it can
be stored and used for road watering. The first group of techniques involves preventing the
runoff from leaving the disturbed areas.  These techniques include:

       •      Berms
       •      Diversion ditches
             Toe ditches
             Small catchments
             Drainage to  pit floor via haul roads and ramps

       The second group of techniques involves the use of rock check dams or hay bales for the
purpose of filtering and temporarily detaining runoff water until some of its sediment load
settles. Check dam size is determined by using the SEDIMOT II computer program. These

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Development Document - Western Alkaline Coal Mining Subcategory
materials are used a short distance downstream from the disturbed land.  They are installed
before soil removal and maintained while the disturbed drainage area is unstable.

       A third group of techniques involves appropriate mine land reclamation practices and
includes:

              Prudent geomorphic design
              Reconstruction of complex slopes
       •       Restoration of drainage density
       •       Roughening of soil surface
       •       Mulching
       •       Contour farming
       •       Timely establishment of permanent vegetative cover

Bridger Coal Company continuously evaluates the effectiveness of sediment control
technologies that are in place at this site as well as the predicted effectiveness of additional
techniques, and modifies the alternate sediment control plan appropriately when necessary.

5.4.3   Alternate Sediment Control Design

       In order to determine the most appropriate ASC techniques for each mining area, Bridger
Coal Company used the computer models SEDEVIOT II and SEDCAD. These models allow
evaluation of disturbed area runoff prior to the disturbance and  simulate the various alternate
sediment control s. These models also allow the determination  of alternate sediment control size
and location necessary to reduce the sediment discharge to levels below the receiving stream
water quality.  Once an alternate sediment control plan has been designed and implemented, a
monitoring program is then used to determine the  effectiveness of the control techniques and
record water quality degradation, should any occur.

       Prior to the original permit application at this site,  surface water quality data showed that
TSS was the only parameter that was consistently  high, and was, therefore, of concern to in
stream water quality. These data are presented in  Table 5k. For this reason, and because of the

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                                   Development Document - Western Alkaline Coal Mining Subcategory
importance of sediment transport in fluvial systems, TSS is the primary water quality parameter
considered in design of alternate sediment control techniques.
Table 5k:   Pre-mining Surface Water Quality Data
Site
BCTR
BCTR
L10MD
L10MD
MOW
MOW
MOW
UDW
U10MD
U10MD
U10MD
U10MD
U10MD
U10MD
U10MD
10MDT
10MDT
10MDT
10MDT
10MR3
10MR3
10MR3
10MR3
10MR3
Type
PD
PD
SC
SC
SC
SC
ss
ss
SC
SC
SC
SC
SC
SC
ss
SC
SC
ss
ss
PD
PD
PD
PD
PD
Date
04/14/80
05/15/80
01/17/80
04/14/80
06/17/80
05/14/80
06/17/80
03/17/80
04/26/79
05/31/79
08/22/79
10/24/79
03/11/80
04/14/80
03/19/81
04/16/80
06/17/80
03/13/80
04/16/80
04/26/79
08/22/79
09/25/79
04/16/80
05/15/80
Iron
(mg/L)
1.47
1.32
1.42
0.52
475.00
1.08
475.00
1.15
0.55
0.47
4.76
0.06
0.16
0.21
1.24
2.78
165.00
164.00
180.65
2.40
23.60
32.00
0.56
0.50
Manganese
(mg/L)
0.044
0.048
0.190
0.033
7.600
0.449
7.600
0.430
0.180
0.050
0.120
-
0.064
0.029
0.190
0.090
3.200
2.100
2.715
0.050
0.260
0.440
0.210
0.200
Field pH
7.20
9.00
-
-
-
-
-
7.80
-
8.40
7.30
8.00
7.70
8.30
-
-
-
-
-
7.80
8.20
6.00
8.80
7.30
TSS
(mg/L)
411.0
303.0
182.0
1240.0
21750.0
66152.0
21750.0
1672.0
24.0
40.0
79.0
52.0
68.0
916.0
56.0
8728.0
8141.0
1532.0
8728.0
68.0
275.0
816.0
71.0
418.0
Discharge
(cfs)
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
18.0
28.0
1.0
-
-
-
-
-
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Site
10MR3
10MR3
10MR3
10MR3
10MR3
10MR3
10MR4
10MR4
10MR4
10MR4
10MR4
10MR4
10MR4
9.5MD
9.5MD
9.5MW
9.5MW
9MW
9MW
9MW
9MW
Type
PD
PD
PD
PD
PD
PD
PD
PD
PD
PD
PD
SC
ss
ss
ss
SC
ss
ss
ss
ss
ss
Date
06/18/80
07/10/80
08/04/80
09/05/80
10/02/80
11/06/80
04/26/79
08/22/79
09/25/79
10/24/79
04/14/80
05/15/80
06/18/80
04/15/80
08/22/79
07/29/81
09/15/81
06/17/80
08/21/79
03/08/80
07/15/81
Iron
(mg/L)
4.12
1.27
3.04
4.20
1.42
3.15
31.00
16.00
1.67
1.59
0.47
0.46
55.50
0.34
1470.00
936.00
930.00
140.00
520.00
42.20
1050.00
Manganese
(mg/L)
0.075
0.130
0.385
0.410
0.020
0.332
0.370
0.190
0.270
0.000
0.120
0.210
1.570
0.450
22.100
-
-
3.500
12.100
0.920
-
Field pH
7.90
7.50
7.20
7.40
8.30
8.75
-
7.80
6.20
7.40
7.40
7.50
6.80
-
-
-
-
-
-
-
-
TSS
(mg/L)
37.0
65.0
180.0
368.0
438.0
-
620.0
348.0
30.0
36.0
19.5
715.0
1700.0
4516.0
3211.0
61600.0
38700.0
11660.0
5373.0
1768.0
93600.0
Discharge
(cfs)
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
72.0
104.0
-
-
19.7
-
PD = Pond; SC = Stream Channels; and SS = Sediment Sampling Stations.
       In the SEDIMOT II and SEDCAD models, the SCS curve number is used for flow runoff
calculations; the Modified Universal Soil Loss Equation (MUSLE) is used for soil loss
calculations; the Muskingum method is used to route water flow; Williams Model I is used to
route sediment in channels; and Yang's unit stream power equation is used to route sediment
overland.  Application of these models allows increased temporal and spatial variability to be
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                                   Development Document -  Western Alkaline Coal Mining Subcategory
incorporated into the analysis, and allows for channel segments and subwatershed areas to be
specified to simulate individual contributions to the total basin output.

       For this site, a database containing TSS concentrations in a small ephemeral stream
during pre-mining, undisturbed conditions existed prior to the initial alternate sediment control
application submittal.  Data from this database are presented in Table 51. From this database, a
design TSS input value for the SEDIMOT II/SEDCAD simulations was calculated. The
arithmetic average of these data (30,000 mg/L) was used as a design criterion to determine the
location and size of the alternate sediment control structures.  Preferably, disturbed area runoff
should be near or below the mean TSS concentration of the observed data (30,000 mg/L). The
actual impact of the mine runoff on the receiving stream water quality was determined from the
data collected from the alternate sediment control monitoring program.

       The actual alternate sediment controls selected differ for each reclaimed area and are
determined by site-specific analysis. As part of this analysis, the company uses SEDIMOT
II/SEDCAD to model the effects of seven alternate sediment control techniques, simulated in
sequence as presented in Table 5m. The sequence is determined by experience with alternate
sediment control effectiveness in reducing sediment discharges.
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Development Document - Western Alkaline Coal Mining Subcategory
Table 51:   Existing Database, Undisturbed TSS Concentration Data
Location
Nine Mile Wash
9.5 Mile Wash @ Crest Gage
Middle Deadman Wash
9.5 Mile Wash @ Temp.
Recording Sta.

Date
08/21/79
03/08/80
10/05/80
10/05/80
07/15/81
08/09/82
08/22/79
07/29/81
09/15/81
08/05/82
5/14/80
06/17/80
09/14/82





9/24/82














TSS
(mg/L)
5,373.0
1,768.0
37,700.0
22,640.0
93,600.0
34,050.0
3,211.0
61,600.0
38,700.0
95,700.0
66,152.0
21,750.0
53,540.0
44,500.0
42,920.0
34,660.0
32,780.0
29,420.0
3,155.0
17,000.0
20,300.0
15,540.0
24,840.0
20,490.0
17,150.0
19,900.0
16,120.0
20,020.0
14,670.0
13,340.0
36,860.0
8,160.0
14,800.0
Peak
Monthly Flow (cfs)
13.0
35.4
50.4
50.4
12.0
55.0
375.0
72.0
104.0
120.0
5.0
8.0
27.0
28.0
22.0
11.0
4.0
1.0
NA1
NA1
NA1
NA1
NA1
NA1
NA1
NA1
NA1
NA1
NA1
NA1
NA1
NA1
NA1
Average = 29,770 (Round to 30,000)
10-Yr.-24-hr.
Peak Discharge (cfs)
1,646.0
625.0
887.0


       1 Not available, hydrograph not recorded.
5-34
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                                  Development Document - Western Alkaline Coal Mining Subcategory
Table 5m:   Order of Simulation of Sediment Control Best Management Practices
Order of Implementation in Design
1
2
3
4
5
6
7
Sediment Control Technique
Rock Check Dams
Interceptor Ditch (Contour Ditch)
Contour Berms
Vegetative Buffer Strip
Toe Drain Ditch
Temporary Barrier
Benches
5.4.4   Monitoring Program


       Monitoring is conducted during runoff events between May 1 and September 30 (when

temperatures are above freezing).  Each monitoring station is serviced generally after each storm,

and at least once per month, from May through September. In addition, checks are performed

every two weeks from May through September.


       Through the first three mining periods, eight paired watersheds (four pairs) and one

control station were equipped with automatic pump samplers and manometers. Each watershed

pair consisted of one disturbed watershed treated with alternate sediment controls and an

undisturbed watershed. The nine sampling stations were:


SWPS-2     Station SWPS-2 was a control watershed location on a tributary of Deadman
             Wash. This station was impacted by mining in 1990 and decommissioned in
             1991. However, no data were collected because very little runoff was generated
             by the small storms that occurred in the watershed since the station was installed.

SWPS-3     Station SWPS-3 is the upstream receiving stream station located near the upper
             mining limit. SWPS-3 is located on Deadman Wash and provides pre-mining,
             undisturbed data.

SWPS-4     Station SWPS-4 was located on Deadman Wash, downstream from SWPS-3.
             SWPS-4 was the disturbed watershed paired with SWPS-3 during the
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Development Document - Western Alkaline Coal Mining Subcategory
             experimental period (1984-1987).  The site was decommissioned in 1987 and
             mined through in 1988.

SWPS-7     Station SWPS-7 was located on Deadman Wash, just above the outlet of the
             SWPS-8 watershed. SWPS-7 was the undisturbed watershed paired with SWPS-8
             during the experimental period (1984-1987). The site was decommissioned in
             1987.

SWPS-8     Station SWPS-8 monitors a disturbed watershed on a tributary of Deadman Wash.
             SWPS-8 is located approximately 1,000 feet upstream from Deadman Wash.

SWPS-9     Station SWPS-9 is a Deadman Wash downstream receiving station that is located
             approximately 100 feet upstream from the confluence of Deadman Wash and
             Nine Mile Draw.

SWPS-10    Station SWPS-10 is a disturbed watershed location on Nine Mile Draw. This
             location is located approximately 300 feet upstream from the confluence of Nine
             Mile Draw and Deadman Wash.

SWPS-13    Station SWPS-13 is upstream from the pit and represents the receiving stream.

SWPS-14    Station SWPS-14 is downstream of all mining disturbance in the Ten Mile Draw
             drainage basin.


5.4.5   Data Reduction
       During the first permit term, the discharge monitoring data were reduced using standard

U.S. Geological Survey (USGS) procedures for continuous sediment and water stage data. The

reduced data were then analyzed using either a covariance test or a modified Student's t-test in

order to determine whether degradation occurred in the receiving stream as a result of the

disturbed area runoff.


       During the second and all subsequent permit terms, the data reduction procedure

followed Porterfield (1972). This procedure is summarized as follows:
5-36
1.      The stage recorder chart is adjusted for applicable pen, data, or time corrections.

2.      Discrete sediment sample data are used to construct a continuous temporal

       sediment concentration graph on the same scale as the flow record.

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                                   Development Document - Western Alkaline Coal Mining Subcategory
       3.      Water stage and sediment graphs are subdivided by mid-intervals into discrete
              water discharge, sediment concentration, and sediment discharge values. In order
              to avoid biasing the data in subsequent analyses, equal time intervals are used for
              the disturbed stream and receiving stream subdivisions.
       4.      The subdivided water discharge and sediment discharge data are used to calculate
              storm sediment yields in tons per acre and storm water yields in acre-feet per
              square mile.
       5.      A log-log data plot of all monitoring stations is prepared with storm sediment
              yield plotted against storm water yield.

5.4.6   Data Analysis

       Once data have been reduced they are analyzed to determine if degradation has occurred
(i.e., sediment yield has increased over background conditions).  During the first permit term
(1984-1987), the discharge monitoring data were reduced using standard USGS procedures for
continuous sediment and water stage data.  The allowable TSS change criteria initially were
based on a statistical comparison of storm sediment concentrations in the receiving stream before
and after addition of the disturbed area runoff.  Sediment data were analyzed with either a
covariance test (for multiple pairs), or a modified Student's t-test (for a single pair of TSS data
points) in order to determine whether the receiving stream (Deadman Wash) was degraded by
runoff from the disturbed area. Since no degradation had been detected in over 65 storms,
alternate sediment control techniques were determined to be successful.

       A simpler method for assessing differences in TSS concentrations between paired
watersheds was approved for the second and subsequent terms of the permit.  First, instantaneous
TSS concentrations and flow rates are collected at adequate intervals to accurately calculate
storm water and sediment yield.  An example of reduced storm yield data is presented in Table
5n.
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Development Document - Western Alkaline Coal Mining Subcategory
Table 5n: Example Water and Sediment Yield Data (1984 -1998)
Station
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-3
SWPS-4
SWPS-4
SWPS-4
SWPS-4
SWPS-4
Date
7/31/84
6/25/85
7/18/85
7/23/85
7/30/85
4/24/86
5/8/86
7/4/86
8/29/86
9/24/86
9/26/86
9/27/86
5/29/87
5/30/87
6/9/87
9/3/87
9/4/87
7/12/89
9/19/89
8/21/90
5/22/91
6/1/91
6/13/91
7/25/91
9/9/91
9/29/91
7/11/92
7/21/92
6/3/93
6/17/93
6/26/93
9/12/94
5/25/96
9/8/95
7/31/84
7/18/85
7/23/85
7/30/85
7/4/86
Stream Type
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Water Yield
(acre-ft/mi2)
1.477484022
0.005176922
0.031431064
0.11673182
0.080180455
0.002708907
0.009636635
0.010107986
0.003897468
0.001839712
0.002459572
0.001592364
0.02346527
0.002834567
0.025076508
0.007832187
0.021765622
0.00843516
0.010161131
0.001368857
0.011213602
0.519122156
0.03358617
0.12759526
0.034409669
0.13113313
0.333143
0.063889
0.094653
0.16531
0.14757
0.005984
0.014834
0.090383
1.281434215
0.038092331
0.089620306
1.315367177
0.017723258
Sediment Yield
(tons/acre)
0.050618459
0.0000418
0.00089235
0.005699971
0.001962336
0.0000293
0.0000606
0.0007701
0.00012434
0.0000272
0.0000167
0.000009
0.00057052
0.0000439
0.0005538
0.00028004
0.00035631
0.00030093
0.00017763
0.000008
0.00036676
0.012856543
0.00099266
0.00192681
0.001002066
0.004085589
0.004893302
0.001587215
0.00055171
0.00061545
0.004199484
0.00011808
0.0000742
0.002519272
0.059088767
0.00066273
0.006017068
0.037101028
0.00096693
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                                       Development Document -  Western Alkaline Coal Mining Subcategory
Station
SWPS-4
SWPS-4
SWPS-7
SWPS-7
SWPS-7
SWPS-7
SWPS-7
SWPS-7
SWPS-7
SWPS-7
SWPS-7
SWPS-7
SWPS-7
SWPS-7
SWPS-7
SWPS-8
SWPS-8
SWPS-8
SWPS-8
SWPS-8
SWPS-8
SWPS-8
SWPS-8
SWPS-8
SWPS-8
SWPS-8
SWPS-8
SWPS-8
SWPS-8
SWPS-8
SWPS-8
SWPS-8
SWPS-9
SWPS-9
SWPS-9
SWPS-9
SWPS-9
SWPS-9
SWPS-9
SWPS-9
SWPS-9
SWPS-9
Date
9/3/87
9/4/87
7/31/84
8/6/84
8/18/84
9/6/84
7/18/85
7/20/85
7/23/85
7/30/85
7/4/86
5/29/87
6/9/87
9/3/87
9/4/87
7/9/84
7/31/84
8/6/84
8/18/84
9/6/84
7/30/85
5/29/87
7/23/89
9/18/89
7/20/90
9/4/90
7/12/92
7/21/92
6/7/93
7/26/93
9/7/95
9/21/97
7/31/84
8/6/84
9/6/84
7/18/85
7/20/85
7/23/85
7/30/85
6/9/87
9/19/89
8/4/90
Stream Type
Disturbed
Disturbed
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Water Yield
(acre-ft/mi2)
0.036651076
0.051385958
0.883773652
0.018663956
0.008212654
0.078186652
0.026335062
0.037043061
0.080330902
1.64197228
0.031810992
0.049678773
0.010749402
0.017177596
0.06342408
0.864063707
2.989430677
1.377395402
0.65060337
2.053912776
7.646761495
0.942419621
16.7603059
1.953010004
0.756138294
24.80262338
3.338507
0.386208
1.28865
2.903206
3.5058
1.292154
0.968139808
0.030162507
0.340016234
0.037446771
0.393764689
0.145318019
2.115498217
0.046868004
0.60228965
0.377490999
Sediment Yield
(tons/acre)
0.002640955
0.001527354
0.03245597
0.00091022
0.00029353
0.002446697
0.00052174
0.001852661
0.004302842
0.036970469
0.001072226
0.002706261
0.00050693
0.0008806
0.001558256
0.039664882
0.346925851
0.128622236
0.029959021
0.0679606
0.747331783
0.034361881
0.85378317
0.05122973
0.017944103
0.729661636
0.040114953
0.03935179
0.008883994
0.129072306
0.220394066
0.048861472
0.066406744
0.001983688
0.023758994
0.00087062
0.024798275
0.005443206
0.129639835
0.003246825
0.013080951
0.009658689
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Development Document - Western Alkaline Coal Mining Subcategory
Station
SWPS-9
SWPS-9
SWPS-9
SWPS-9
SWPS-9
SWPS-9
SWPS-9
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
Date
5/15/91
8/4/91
9/7/95
9/21/97
7/24/98
7/25/98
8/3/98
7/21/84
7/31/84
8/1/84
8/4/84
8/23/84
9/6/84
9/13/84
9/21/84
6/25/85
7/18/85
7/20/85
7/23/85
7/30/85
9/2/85
9/11/85
9/19/85
7/4/86
7/9/86
9/8/86
7/11/87
9/4/87
7/26/88
8/3/88
7/12/89
7/23/89
9/18/89
9/19/89
9/20/89
7/20/90
7/24/90
8/4/90
8/30/90
6/1/91
6/13/91
8/27/91
Stream Type
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Receiving
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Water Yield
(acre-ft/mi2)
0.524044071
0.137681387
1.280506
0.808959
0.233039
0.114991
0.070143
0.027840712
1.273303295
0.059938324
0.024953331
0.187992353
1.220188727
0.29014207
0.086033362
0.225655459
0.088624058
1.274837051
0.490645525
1.892771051
0.301326036
0.224095213
0.285482526
0.065318389
0.03566578
0.040836576
0.045726581
1.077011708
0.345285
0.881732
10.2879986
9.266459047
0.204264997
1.70304627
0.350679062
0.005629069
6.277730829
0.207790781
1.216872212
1.261933901
0.289479827
0.068529
Sediment Yield
(tons/acre)
0.00476637
0.003731229
0.037841673
0.036334021
0.006275786
0.003876858
0.003449813
0.00060744
0.063190439
0.001226025
0.00072447
0.004881808
0.024843723
0.01063298
0.00068546
0.004346816
0.003332559
0.057595307
0.016545764
0.07519991
0.014233035
0.004608739
0.00433567
0.003137509
0.00096967
0.001148005
0.00097525
0.01375377
0.023645
0.034852
0.4594194
0.493653359
0.007283703
0.026197923
0.004809361
0.00015047
0.26287646
0.010900476
0.064923592
0.079357249
0.013982257
0.00109785
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                                   Development Document -  Western Alkaline Coal Mining Subcategory
Station
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
SWPS-10
S WPS- 13
SWPS-14
S WPS- 14
Date
9/9/91
9/29/91
6/3/93
6/17/93
7/26/93
8/11/93
9/17/93
9/18/93
9/8/95
9/21/97
9/21/97
9/21/97
7/99/98
Stream Type
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Disturbed
Receiving
Disturbed
nistiirhpH
Water Yield
(acre-ft/mi2)
0.040127
0.019763991
0.38052
0.820869
0.576255
0.077249
0.030802
1.749732
0.155225
2.60624
9.156198
0.039105
0 009494
Sediment Yield
(tons/acre)
0.00635304
0.00064645
0.006587097
0.007857705
0.019192863
0.002496633
0.00046812
0.02525054
0.004313379
0.107340165
0.139136745
0.001971105
0 000^9969
       Next, the 95% prediction bands confining the regression equation y = 0.0339(x) L0925  are
calculated using Equation 5a developed for predicting any value of "y" for a given "x"
(Kleinbaum, 1978). Unit water and sediment yield are plotted with the 95% prediction intervals
in Figure 5c, and a graphical comparison is made of the individual storm sediment yield relative
to the general trend. Any points (storms) which fall inside the 95% prediction interval show that
no significant variation from background sediment yield has occurred.  If the disturbed
monitoring station points (storms) plot above the predicted interval, degradation has technically
occurred and mitigation measures are immediately taken. No unit sediment yields, of storms less
than a 10-year, 24-hour event, plotted outside of the confidence bands between 1984 and 1998.
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Development Document - Western Alkaline Coal Mining Subcategory
Equation 5a
y0 =  Y
                              X) ± t(n_2> ^  * Sy/x
      1      (Xn  - X)2
(1 +  1  + _J_2	L
      n    (n  - 1) *  S
              Where:
                      = Mean of Y values
                X    = Mean of X values
              B]  = Coefficient of Regression Equation
              X0  = Value in Question
              y0  = Value in Question
              t (n-2, i-a/2) = t statistic
              n = Number of values
              S 2 = Variance of x values
                          Sy/x  -
                                   *(Sy2"(Bi2  * s*)
              Where:
                      Sy2 = Variance of Y values
                      n = Number of values
                      Sx2 = Variance of X values
                      B]  = Coefficient of Regression Equation
5-42
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                                  Development Document - Western Alkaline Coal Mining Subcategory
                Figure 5c:  Sediment Yield vs. V\feter Yield
           10
   0)
           0.1 :
   o
   •5
   §      0.01
   (1)

   ^
   0)
         0.001
        0.0001
       0.00001
      0.000001
                          = 0.0339x10925
                           F? = 0.9321
                               •   Dsturbed 1984-1998
                               n   Receiung 1984-1998
                            ---x--- Upper 95% Band
                            ...+-.. Lower 95% Band

                                  • Regression Line
            0.001
0.01          0.1           1            10
        Water Yield (acre-ft/sq.mi.)
100
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Development Document - Western Alkaline Coal Mining Subcategory
       To confirm that the use of alternate sediment controls is effective, Bridger also conducts
annual surveys of the receiving streams. For example, Bridger Coal Company has conducted an
annual survey of Nine and One-Half Mile Draw since 1987. The surveys include up to nine
cross sections used to model Nine and One-Half Mile Draw. Two cross sections are located
upstream from the final highwall, three are located in the reclaimed reach, and four are located
downstream from the boxcut disturbance limit. Areas of head cutting, aggradation, or
degradation are noted and reported each year. Based on data available (up to 1992), no
aggradation or degradation has been detected downstream of the disturbance in Nine and One-
Half Mile Draw.

5.4.7   Summary

       Alternate sediment control technology is the primary means of sediment control at the
Jim Bridger Mine. Ongoing surface water monitoring is used to detect the impact of mine
disturbance treated with ASC techniques on receiving stream water quality.  Analysis of
monitoring results to date (1984-1998, Table 5m) has shown that, for storm events less than 10-
year, 24-hour, background sediment levels have not been exceeded in disturbed watersheds.
Analysis also has shown that sediment in disturbed watersheds correspond to sediment in
receiving watersheds relative to sediment storage and release. These alternate sediment control
design and  monitoring methods have proven successful over a lengthy period of
experimentation, evaluation, and application.
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                                  Development Document - Western Alkaline Coal Mining Subcategory
5.5    Case Study 5 (Water Engineering & Technology, Inc., 1990)

       Case Study 5 summarizes a study performed for the Office of Surface Mining
Reclamation and Enforcement during 1987-1989.  This extensive project was jointly
commissioned by the National Coal Association, the Office of Surface Mining Reclamation and
Enforcement, BHP-Utah International Inc., Peabody Coal Company, and the Pittsburgh and
Midway Coal Mining Company and was prepared by Water Engineering & Technology, Inc.
(WET, Inc.).  Details of the project are provided in the "Determination of Background Sediment
Yield and Development of a Methodology for Assessing Alternative Sediment Control
Technology at Surface Mines in the Semiarid West" (WET, Inc., 1990).

The study had four major objectives:

             Assess average annual background sediment yield at three mine sites based on
             surveying and computation of sediment accumulation in ponds;
             Evaluate available computer models for prediction of watershed runoff and
             sediment yield and select the model that best represents these processes at
             semiarid mine sites;
             Evaluate runoff and erosion response to rainfall using rainfall simulation testing
             on test plots (12 feet wide by 35 feet long). Use resulting data and information to
             calibrate and validate the computer model selected; and
             Apply the model to evaluate alternative sediment control practices and the ability
             of such practices to maintain erosion from reclaimed lands at or below
             comparable background erosion levels.

       The study targeted sedimentation and erosion conditions in  semiarid coal regions using
data and information collected at the at Navajo Mine near Farmington, New Mexico (BHP-Utah
International, Inc.), McKinley Mine near Gallup, New Mexico (Pittsburgh & Midway Coal
Company), and the Black Mesa Mine near Kayenta, Arizona (Peabody Coal Company).  All
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Development Document - Western Alkaline Coal Mining Subcategory
three mines are located in a semiarid environment where sediment yield is large and variable.
Erosion generally results from the occurrence of short duration, high intensity rainfalls.

5.5.1   Background Sediment Yield

       Surveys were conducted in ponds located near the McKinley and Navajo Mines to
determine average sediment yields from undisturbed, semiarid watershed basins. No suitable
ponds were identified at the Black Mesa Mine.

       Eight ponds were surveyed near the McKinley Mine.  Measured sediment yields
(sedimentation rate, tons/acre/year) ranged from 0.11 to 3.2 tons/acre/year.  The average
sediment yield was 1.16 tons/acre/year with a standard deviation of 1.13 tons/acre/year.  The
lowest value of sediment yield was measured in a pond corresponding to basins with low relief
and low hillslope gradients (MCM-3).  The highest values of sediment yield were measured in
ponds corresponding to basins with incised channels (MCM-1, 2, and 8).  Ten ponds were
surveyed near the Navajo Mine. Measured sediment yields for the Navajo Mine ponds ranged
from 1.56 to 16.00 tons/acre/year. The average sediment yield was 4.82 tons/acre/year with a
standard deviation of 4.54 tons/acre/year.

       Sediment volume, sediment density, and sedimentation rate results from basins located
near the McKinley and Navajo Mines are presented in Table 5o. The high variability in
sediment yields is thought to be attributed in part to the age of the ponds (from 8 to 38 years),
size of the basin  drainage areas (averages are 0.17 and 0.64 square miles for Navajo and
McKinley Mines, respectively), and types of soil (clay, sandy loam, loam, sandy clay loam, and
clay loam).
5-46                                                                          Case Studies

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                                  Development Document -  Western Alkaline Coal Mining Subcategory
Table 5o:   Measured Sediment Yields at Navajo and McKinley Coal Mines
Pond
NM-2
NM-3
NM-4
NM-5
NM-6
NM-7
NM-8
NM-9
NM-10
NM-11
MCM-1
MCM-2
MCM-3
MCM-4
MCM-6
MCM-7
MCM-8
MCM-9
Sediment
Volume
(ft3)
152,440
115,060
39,110
25,140
5,180
55,440
21,860
25,390
221,780
113,710
175,690
220,100
71,000
137,830
120,310
105,770
642,370
154,350
Drainage
Area
(acres)
109
183
42.2
57.6
19.2
71.6
5.1
64.0
320
192
89.6
110.2
570
211
580.4
173
224
509
Age
(years)
8
8
8
8
8
8
8
8
8
15
33
34
33
33
38
37
36
31
Sediment
Density
(lbs/ft3)
107
100
77.8
82.6
92.7
60.6
60.6
87.1
89.1
82.3
68.9
72.7
58.5
68.5
81.0
71.5
79.4
69.4
Sedimentation
Rate
(tons/acre/yr)
9.36
3.93
4.50
2.25
1.56
2.93
16.00
2.16
3.86
1.62
2.05
2.13
0.11
0.68
0.23
0.59
3.16
0.34
       NM = Navajo Mine
       MCM = McKinley Mine
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Development Document - Western Alkaline Coal Mining Subcategory
       In general, sediment yields measured from the Navajo Mine basins were greater than
those from the McKinley Mine basins. This observation has been attributed to the following
factors:

              Average drainage area for the Navajo Mine basins (0.17 square miles) is less than
              the average drainage area for basins at the McKinley Mine (0.64 square miles);
              Drainage density is greater at the Navajo Mine basins (15.2 miles/square miles)
              than at the McKinley Mine basins (4.2 miles/square miles);
       •       The vegetation density is greater near the McKinley Mine basins (41 percent)
              than for basins near the Navajo Mine (15 percent); and
       •       The Navajo Mine basins have badland soil associations and none of the McKinley
              mine basins have badland soil associations.

       The usefulness of this information for evaluation of background sediment yield is limited
by several factors. First, the age of the the ponds was often uncertain and some may not have
been in existence long enough to have received runoff and sediment resulting from large storm
events that control watershed response in a semiarid environment. Second, reliable
measurements of sediment yield can only be obtained if the ponds have not been breached or
overtopped, and this information was  not known.  Third, ponds should be located in basins
having geologic properties and morphometric (drainage area and density) properties similar to
those of the mine watersheds. Some of the ponds near the McKinley mine did not meet this
latter condition and exhibited low rates of sediment yield possibly due to the presence of
geologic controls in channels and watersheds (i.e., exposed bedrock). Finally, sediment yield in
the semiarid west is largely governed  by the occurrence of localized, relatively large storm
events. Without accurate data describing the rainfall conditions in the watershed, it is difficult to
compute a meaningful average annual sediment yield. It is difficult to determine if the sediment
yield is the result of a single, rare storm event (i.e., 50-year storm) or the result of a sequence of
smaller events. Lacking accurate rainfall data, pond sediment volumes could not be used to
directly calibrate a computer model.
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                                   Development Document - Western Alkaline Coal Mining Subcategory
5.5.2   Evaluation of Watershed Computer Models


       The second objective of the study was to assess available watershed hydrologic and

sediment transport models to determine the model most appropriate for use in evaluation of

alternative sediment control practices. Detailed evaluations were made of five models (Water
Engineering & Technology, 1990):

       •      ANSWERS - Areal Nonpoint Source Watershed Environmental Response
             Simulation
       •      KINEROS - Kinematic Erosion Model
             MULTSED - Watershed and Sediment Runoff Simulation Model for Multiple
             Watersheds
       •      PRMS - Precipitation-Runoff Modeling System
             SEDIMOT II/SEDCAD version - Hydrology and Sedimentology Watershed
             Model II


Each model was evaluated with respect to:
       •      Watershed representation;
       •      Rainfall components;
       •      Infiltration, interception and surface  detention components;
       •      Runoff components;
       •      Sedimentation components;
       •      Ease of file generation;
       •      Performance with test data; and
       •      Sensitivity analysis of the various inputs and parameters.


       Rather than developing an artificial data set  to test the models, a data set obtained from

the USDA-ARS Sedimentation Laboratory, Oxford Mississippi for a 4.7 acre, severely eroding

soybean field in northwest Mississippi was used. These data include nine events that occurred
during the 1985-1986 growing season and represent a wide range of vegetation cover. Two of

the nine events were relatively extreme (both of approximate 10-year return periods, one having

a duration of two hours and the other having a duration of four hours).  Accurate measurements

of rainfall, runoff and sediment yield were available for each event at this site, and the

topography of the field was surveyed in great detail. Although this data set does not represent

coal mines in a  semiarid environment, the processes of infiltration, runoff generation, soil

detachment, sediment transport and deposition can be considered universal.


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Development Document - Western Alkaline Coal Mining Subcategory
       Results of computer model tests are presented in Table 5p.  Five models were ranked
from one (most accurate) to five (least accurate) for seventeen categories.  Twelve categories
deal with physical processes. The other categories are (1) watershed representation, (2)
generalization of watershed reproduction, (3) ease in subdividing watersheds and generating
watershed data, (4) ease in generating other data files, and (5) performance of the model with test
data.

Table 5p:   Ranking of Five Computer Models
Category
Rainfall
Interception
Infiltration
Hillslope
Channel
Runoff
Hillslope
Channel
Detachment
Hillslope
Channel
Transport
Hillslope
Channel
Deposition
Hillslope
Channel
Watershed Representation
Generality
Generation
Performance with Test Data
Data File Generation
Areas of Concern
Sum of Ranks
Number of First Ranks
ANSWERS
P 2
P 3
E 4
N 4
P 2
P 2.5
P? 2.5
N 3
P? 1.5
P? 1.5
P? 1
P? 1.5
1.5
5
3
4
2
44
8
KINEROS
P 2
P 3
P 2
P 2
P 1
P 2.5
P? 2.5
P? 2
P? 3
P? 3
P? 2
P? 3
1.5
3
1.5
2
3
39
7
MULTSED
P 2
P 1
P 2
P 1
P 4
P 2.5
P? 2.5
P? 1
P? 1.5
P? 1.5
N 4
P? 1.5
4
3
1.5
3
1
37
12
PRMS
P 4
P 3
P 2
N 4
P 3
P 2.5
P? 2.5
N 4.5
P? 4
P? 4.5
N 4
N 5
4
3
(1 to 5)
5
5
(60 to 65)
3
SEDIMOT
II
S 5
S 5
S 5
N 4
S 5
P-S 5
S 5
N 4.5
S 5
E 4.5
N 4
E 5
4
1
4
1
4
70
2
       E = Empirical Relationship; N = Not Simulated; P = Process Based; P? = Process Assumption
       1 = Highest Rank; 5 = Lowest Rank
5-50
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                                   Development Document - Western Alkaline Coal Mining Subcategory
       As a result of these analyses, the MULTSED model achieved the most number of first
place scores.  Therefore, MULTSED was selected for use in subsequent phases of this project.

5.5.3   Rainfall Simulation Data Collection

       Rainfall simulation testing was conducted at the Navajo Mine during 1987 and 1988 and
at the McKinley Mine during 1988 to measure and collect data regarding the following
parameters:
              Rainfall
              Runoff
              Sediment yield
              Soil properties
              Vegetation and cover densities

       By testing paired plots (one plot to be used for model calibration and one to be used for
model verification) and collecting data from two simulated rainstorms, four sets of data were
obtained from each test site. Test sites encompassed a range of slopes, ages of reclamation and
reclamation practices and included five test sites in undisturbed areas at each mine. The rainfall
simulation testing program provided 76 data sets describing the rainfall-runoff-erosion process at
the Navajo Mine (19 sites x 2 plots x 2 test runs) and 80 data sets at the McKinley Mine (20 sites
x 2 plots x 2 test runs).

       In addition, data were available for the Black Mesa Mine from 24 test plots (10-feet wide
by 35-feet long) representing a range of slopes, surface treatments and watershed size (from 3 to
41 acres).  Runoff and sediment yield generated by natural rainfall for Navajo Mine and
McKinley Mine test plots and Black Mesa Mine watersheds were available for the period of
1983 to 1987.  Tables  5q, 5r, and 5s contain a summary of the runoff and sediment yield
information obtained from the Navajo, McKinley, and Black Mesa Mines, respectively.
Case Studies                                                                          5-51

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Development Document - Western Alkaline Coal Mining Subcategory
 Table 5q:   Rainfall, Runoff and Sediment Yield Data for Navajo Mine
Plot
1
2
3
4
5
6
Storm
Event
Run
1
1
2
2
1
1
2
2
1
1
2
2
1
1
2
2
3
3
1
1
2
2
1
1
2
2
3
3
4
4
SubPlot
ID
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Total Rainfall
(in)
2.5
2.2
2.6
2.6
2.0
2.0
2.7
2.6
2.0
2.7
2.1
2.4
2.3
1.8
2.2
1.0
2.1
1.4
2.0
2.3
2.7
2.2
2.9
2.7
2.8
2.6
NDC
2.4
NDC
1.4
Total Runoff
(in)
1.42
0.72
2.02
2.08
0.91
1.23
1.66
1.76
0.75
0.85
1.31
1.31
1.97
1.72
1.36
0.87
1.88
1.06
0.28
0.71
0.90
0.98
0.40
0.33
1.10
1.18
NDC
1.32
NDC
1.05
Total Sediment
Yield
Obs)
27.0
6.7
36.8
33.0
16.3
18.0
41.2
34.9
10.1
13.0
32.4
30.0
38.2
28.3
17.6
9.0
23.6
10.6
0.8
1.4
6.1
5.4
0.0
0.6
1.8
5.0
-
2.2
-
1.5
Average Sediment
Concentration
(ppm)
8,690
4,240
8,320
7,260
8,180
6,690
11,400
9,070
6,210
6,970
11,300
10,500
8,890
7,530
5,920
4,720
5,740
4,600
1,310
922
3,110
2,530
35
849
727
1,920
-
759
-
636
5-52
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                                       Development Document - Western Alkaline Coal Mining Subcategory
Plot
7
8
9
10
11
12
13
14
Storm
Event
Run
1
1
2
2
1
1
2
2
3
3
1
1
2
2
1
1
2
2
1
1
2
2
1
1
2
2
1
1
2
2
1
1
2
SubPlot
ID
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Total Rainfall
(in)
2.3
2.2
2.6
2.3
3.1
2.0
2.7
2.7
2.2
1.8
2.3
2.7
2.4
2.2
2.6
2.7
2.1
2.3
2.3
2.2
2.4
2.0
2.2
2.2
2.5
2.3
2.4
2.2
2.7
2.4
2.3
2.4
2.2
Total Runoff
(in)
0.50
0.81
0.68
1.14
0.27
0.32
0.14
0.14
0.42
0.42
1.32
0.53
2.26
1.89
1.24
1.20
1.62
1.50
1.12
1.02
1.68
1.29
1.32
1.26
2.07
1.94
0.00
0.00
0.41
0.44
0.36
0.17
1.66
Total Sediment
Yield
Obs)
0.3
0.4
0.6
0.6
0.3
0.2
0.1
0.1
0.4
0.4
209.0
244.8
341.1
240.8
4.8
4.0
7.5
7.6
6.9
11.5
22.5
19.2
209.2
176.2
314.7
306.1
0.0
0.0
0.8
1.0
1.2
0.4
11.8
Average Sediment
Concentration
(ppm)
283
238
281
224
501
359
434
416
471
404
72,500
73,200
68,900
58,300
1,790
1,550
2,130
2,320
2,800
5,160
6,150
6,800
72,200
64,100
69,600
72,200
0
0
866
1,050
1,490
996
3,240
Case Studies
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Development Document - Western Alkaline Coal Mining Subcategory
Plot
14
15
16
17
18
19
Storm
Event
Run
2
1
1
2
2
1
1
2
2
1
1
2
2
1
1
2
2
1
1
2
2
SubPlot
ID
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Total Rainfall
(in)
2.6
2.6
2.6
2.5
2.6
2.5
2.6
2.9
2.9
2.4
2.4
2.8
2.8
2.3
2.0
2.5
2.5
2.6
2.3
3.1
2.5
Total Runoff
(in)
1.58
0.00
0.20
0.70
1.50
0.55
0.47
2.51
2.56
2.03
1.97
2.50
2.69
0.63
0.28
1.24
1.30
2.33
1.98
2.92
1.90
Total Sediment
Yield
Obs)
9.6
0.0
0.4
1.4
7.2
1.6
2.2
5.5
6.1
107.6
98.9
106.3
136.4
0.8
0.2
2.3
1.4
38.3
35.3
46.5
36.0
Average Sediment
Concentration
(ppm)
2,790
0
809
945
2,200
1,380
2,100
1,010
1,080
24,200
23,000
19,400
23,200
569
396
849
496
7,530
8,150
7,280
209.0
5-54
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                                   Development Document - Western Alkaline Coal Mining Subcategory
Table 5r:   Rainfall, Runoff and Sediment Yield Data for McKinley Mine
Plot
1
2
3
4
5
6
7
8
Run
1
1
2
2
1
1
2
2
1
1
2
2
1
1
2
2
1
1
2
2
1
1
2
2
1
1
2
2
1
1
SubPlot
ID
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Total
Rainfall
(in)
1.9
2.8
3.0
2.4
1.9
1.8
2.7
2.6
2.8
2.1
3.0
1.8
2.5
3.4
2.6
3.0
3.6
3.2
3.1
2.9
2.5
3.0
3.1
3.0
3.1
2.9
2.4
3.3
2.7
2.8
Total
Runoff
(in)
0.09
0.98
0.81
1.05
0.09
0.06
0.62
0.41
0.74
0.61
1.43
0.77
1.02
1.32
1.63
1.68
1.40
0.87
1.74
1.09
0.82
1.46
1.45
1.71
0.53
0.012
0.98
1.28
1.02
0.94
Total
Sediment
Yield
Obs)
0.6
6.2
6.3
6.0
0.1
0.1
2.4
3.7
4.1
18.8
8.2
4.6
6.2
7.3
6.7
5.9
15.1
13.8
14.6
12.2
4.8
8.6
7.0
10.5
0.5
0.04
0.5
2.8
3.8
2.8
Average
Sediment
Concentration
(ppm)
3,150
2,880
3,550
2,630
689
735
1,400
3,350
2,520
14,000
2,610
2,750
2,800
2,530
1,880
1,590
4,940
7,240
3,830
5,100
2,680
2,690
2,210
2,820
322
1,530
184
923
1,710
1,340
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Development Document - Western Alkaline Coal Mining Subcategory
Plot
8
9
10
11
12
13
14
15
16
Run
2
2
1
1
2
2
1
1
2
2
1
1
2
2
1
1
2
2
1
1
2
2
1
1
2
2
1
1
2
2
1
1
SubPlot
ID
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Total
Rainfall
(in)
3.1
2.9
2.3
3.1
2.8
2.9
3.2
2.9
2.6
2.2
3.1
3.4
3.2
2.5
2.9
3.0
1.9
2.4
2.3
3.1
2.5
2.6
2.6
2.3
2.5
2.7
2.4
2.5
2.3
3.1
2.6
2.4
Total
Runoff
(in)
1.81
1.86
0.46
0.81
1.13
1.02
0.42
0.17
1.04
0.45
0.89
1.44
2.05
1.66
1.67
1.88
1.28
2.21
0.74
0.98
1.27
1.41
1.48
1.22
1.47
1.75
1.65
1.46
2.00
2.19
2.38
1.98
Total
Sediment
Yield
Obs)
7.3
7.8
1.9
8.2
8.4
12.6
5.6
0.6
9.3
3.3
19.5
39.1
44.2
31.2
21.5
17.1
10.9
14.1
12.0
32.3
19.4
31.5
7.0
5.4
6.5
8.6
7.1
8.3
9.3
10.9
153.7
115.7
Average
Sediment
Concentration
(ppm)
1,840
1,910
1,910
4,640
3,420
5,650
6,180
1,650
4,100
3.340
10,010
12,470
9,850
8.580
5,900
4,170
3,920
2,920
7,430
15,050
6,980
10,230
2,150
2,000
2,040
2,260
1,960
2,610
2,120
2,280
29,500
26,780
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                                       Development Document - Western Alkaline Coal Mining Subcategory
Plot
16
17
18
19
20
Run
2
2
1
1
2
2
1
1
2
2
1
1
2
2
1
1
2
2
SubPlot
ID
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Left
Total
Rainfall
(in)
2.4
2.2
3.0
2.8
3.0
3.4
2.3
3.1
3.1
2.5
2.7
2.7
2.7
3.3
2.4
2.6
2.7
2.8
Total
Runoff
(in)
1.89
1.83
0.35
0.55
0.90
1.09
0.80
1.10
1.78
1.42
0.99
0.57
1.90
1.90
1.54
1.62
2.19
2.27
Total
Sediment
Yield
Obs)
100.5
81.3
4.8
9.6
6.0
13.3
11.7
40.5
53.6
42.1
3.0
2.0
4.9
4.8
86.5
95.8
93.4
100.0
Average
Sediment
Concentration
(ppm)
24,290
20,350
6,330
7,960
3,070
5,550
6,730
16,890
13,760
13,550
1,320
1,420
1,130
1,050
25,710
27,070
19,510
20,160
Case Studies
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Development Document - Western Alkaline Coal Mining Subcategory
Table 5s:   Rainfall, Runoff and Sediment Yield Data for Black Mesa and Kayenta Mines
Watershed
N2 Small
N2 Large
J27
Run
Date
7-21-86
8-31-86
9-23-86
7-30-87
8-31-86
9-23-86
7-30-87
7-21-86
8-31-86
7-30-87
7-21-86
8-31-86
9-23-86
7-30-87
8-31-86
9-23-86
8-31-86
9-23-86
7-30-87
8-31-85
9-11-85
7-20-86
9-23-86
8-31-85
9-11-85
7-20-86
9-23-86
8-31-85
9-11-85
7-20-86
Plot ID
221



222


223


224



225

226


271



272



273


Total Rainfall
(in)
0.9
0.5
0.9
0.6
0.5
0.9
0.6
0.9
0.5
0.6
0.9
0.5
0.9
0.6
0.5
0.9
0.5
0.9
0.6
0.5
0.3
0.5
1
0.5
0.3
0.4
1
0.5
0.3
0.5
Total Runoff
(in)
0.012
0.162
0.057
0.195
0.256
0.103
0.147
0.005
0.116
0.067
0.005
0.094
0.024
0.068
0.161
0.138
0.184
0.149
0.219
0.004
0.010
0.006
0.010
0.006
0.010
0.007
0.010
0.027
0.007
0.005
Total Sediment
Yield
Obs)
0.190
4.391
0.208
1.709
8.077
1.172
4.049
0.012
1.849
0.282
0.010
0.796
0.042
0.275
3.049
0.250
4.538
0.377
1.418
0.004
0.002
0.003
0.003
0.015
0.008
0.011
0.067
0.098
0.010
0.009
Average Sediment
Concentration
(ppm)
8,710
14,900
1,990
4,810
17,300
6,260
15,100
1,360
8,720
2,330
1,120
4,630
960
2,230
10,400
991
13,500
1,390
3,560
500
107
288
156
1,440
442
893
3,720
1,970
876
886
5-58
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                                       Development Document - Western Alkaline Coal Mining Subcategory
Watershed
J27(cont.)
J3
Run
Date
9-23-86
8-31-85
9-11-85
9-23-86
8-31-85
8-31-85
9-11-85
9-23-86
7-29-85
9-11-85
9-18-85
8-29-86
9-08-86
8-08-87
7-29-85
9-11-85
9-18-85
8-29-86
9-08-86
8-08-87
7-29-85
9-11-85
9-18-85
8-29-86
9-08-86
8-08-87
7-29-85
9-11-85
9-18-85
8-29-86
9-08-86
8-08-87
7-29-85
Plot ID

274


275
276


303





304





305





306





307
Total Rainfall
(in)
1
0.5
0.3
1
0.5
0.5
0.3
1
1
0.6
0.5
0.2
0.3
0.9
1
0.6
0.5
0.2
0.3
0.9
1
0.6
0.5
0.2
0.3
0.9
1
0.6
0.5
0.2
0.3
0.9
1
Total Runoff
(in)
0.078
0.008
0.005
0.049
0.037
0.017
0.003
0.047
0.307
0.100
0.026
0.015
0.017
0.030
0.436
0.118
0.085
0.015
0.033
0.102
0.436
0.176
0.133
0.048
0.089
0.176
0.257
0.024
0.023
0.026
0.028
0.101
0.163
Total Sediment
Yield
Obs)
0.167
0.013
0.002
0.089
0.087
0.026
0.000
0.095
7.802
0.455
0.132
0.155
0.198
0.390
10.538
0.512
0.143
0.153
0.315
1.160
16.936
1.529
0.400
0.847
1.508
4.009
3.354
0.098
0.067
0.318
0.144
0.861
3.755
Average Sediment
Concentration
(ppm)
1,180
984
242
997
1,310
848
0
1,110
13,900
2,490
2,770
5,850
6,270
7,130
13,300
2,390
927
5,650
5,270
6,230
21,300
4,760
1,650
9,730
9,280
12,500
7,170
2,270
1,620
6,700
2,810
4,690
12,700
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Development Document - Western Alkaline Coal Mining Subcategory
Watershed
J3 (cont.)
N6
Run
Date
9-11-85
9-18-85
8-29-86
7-29-85
9-11-85
9-18-85
8-08-87
9-18-85
9-23-86
9-18-85
9-23-86
9-18-85
7-21-86
9-08-86
9-23-86
9-18-85
7-21-86
9-08-86
9-23-86
9-18-85
7-20-86
7-21-86
9-23-86
9-18-85
7-20-86
7-21-86
9-23-86
Plot ID



308



261

262

263



264



265



266



Total Rainfall
(in)
0.6
0.5
0.2
1
0.6
0.5
0.9
0.4
0.8
0.4
0.8
0.4
0.6
0.9
0.8
0.4
0.6
0.9
0.8
0.4
0.5
0.6
0.8
0.4
0.5
0.6
2.5
Total Runoff
(in)
0.084
0.024
0.006
0.180
0.080
0.024
0.028
0.023
0.074
0.018
0.072
0.003
0.012
0.191
0.090
0.017
0.017
0.106
0.115
0.006
0.005
0.028
0.045
0.010
0.005
0.018
0.039
Total Sediment
Yield
Obs)
0.397
0.067
0.019
4.953
0.879
0.163
1.097
0.407
0.445
0.060
0.330
0.006
0.037
1.200
0.144
0.034
0.060
1.219
0.750
0.012
0.032
0.218
0.132
0.018
0.019
0.135
0.103
Average Sediment
Concentration
(ppm)
2,600
1,530
1,900
15,100
6,020
3,760
21,300
9,510
3,290
1,820
2,540
1,190
1,670
3,450
884
1,090
1,900
6,310
3,570
1,130
3,880
4,200
1,610
993
1,980
4,110
1,440
5-60
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                                  Development Document - Western Alkaline Coal Mining Subcategory
5.5.4  Calibration and Validation of the MUL TSED Model

       The first step in the application of MULTSED for prediction of runoff and sediment yield
involved calibration and validation of the model using the data collected from the Navajo,
McKinley, and Black Mesa/Kayenta mines. One-half of the simulated rainfall test plot data were
used for calibration and determination of appropriate infiltration and soil detachment
coefficients. Following calibration, the MULTSED model was run using the calibrated
infiltration and detachment coefficients to predict sediment yield and mean sediment
concentration.  Finally, total runoff, sediment yield, and mean sediment concentration predicted
by MULTSED were compared to the remaining half of the simulated rainfall test plot data and to
the available Black Mesa/Kayenta Mine  data.  Model verification determined that runoff
amounts were predicted with the greatest accuracy, followed by mean concentration, and
sediment yields.

       Model results also showed a tendency for the model to over predict sediment.  Runoff
rates for low flow conditions should not be of major concern, because long-term erosion rates
generally are dominated by extreme conditions when large magnitude runoff volumes occur.
However, when predicting the runoff and sediment responses of various erosion control
alternatives, the model should not be used for small storms that produce small amounts of runoff
(<0.5 inches).

5.5.5   Evaluation of Alternative Sediment Control Techniques

       Successful calibration and validation of the MULTSED model provided a means to
evaluate the effectiveness of alternative sediment  control techniques relative to background
conditions.  To make these comparisons, a procedure was developed that uses rainfall depth-
duration information available from National Oceanic and Atmospheric Administration (NOAA)
Atlases at each mine site. Rainfall  data describing storm events with recurrence intervals of 2, 5,
10, 25, 50, and 100 years were used to develop hypothetical storm distributions.  MULTSED
Case Studies                                                                         5-61

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Development Document - Western Alkaline Coal Mining Subcategory
was then used to determine the runoff and sediment generated from a hill slope for this range of
storm events.

       Comparisons were made between background sediment yield and predicted sediment
yields associated with alternative sediment control techniques.  Average annual sediment yield
was computed using a probability weighting procedure that uses an incremental probability of
occurrence of the aforementioned sequence of storms.  Since the average value computed using
this procedure is based on a broad range of storm events, it is expected to represent a reasonable
long-term average.  It should be noted that, depending on the sequence of storm events that
actually occur, sediment yield within any given year could significantly deviate from this
average value. For purposes of comparison, however, this calculation procedure provides a
reasonable value for sediment yield.

       Modeling was performed to evaluate sediment yield response to variations in slope
length, slope gradient, cover density, and the presence or absence of furrows (depression storage)
on the reclaimed surface. The results agreed with expectations: sediment yield increases with
increasing plot slope gradient and slope length, decreases with increasing vegetative cover, and
decreases with increased depression storage. Model prediction results for the sediment yield
response to ASCs at the Navajo Mine, McKinley Mine, and Black Mesa/Kayenta Mine are
presented in Figures 5d through 5q.
5-62                                                                           Case Studies

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                                    Development Document -  Western Alkaline Coal Mining Subcategory
Figure 5d: NavajoMine Sediment Yield vs. Plot
0.16 -,
^ 0.14 -
O
ro
J2 0.12 -
2
•a 0.1 -
01
^
£, 0.08 -
c
Ol
.± 0.06 -
•c
Ol
OT
— 0.04 -
ro
c
C 0.02 -
0 -
C
Slope
,+




+' ^^*
^^*
^ '








5 10 15 20 25 30
Plot Slope (Percent)
	 • 	 Unmined Sandy Loam; 5% Cover 	 A 	 Unmined Sandy Loam; 10% Cover
- -• -Reclaimed Sandy Loam; 10%Cover;0.1 inch Furrow s 	 x 	 Unmined Sandy Loam;15% Cover
- -+- - Reclaimed Sandy Loam; 5% Cover; No Furrow
                     Figure 5e: Navajo Mine Sediment Yield vs. Percent
                                         G round Cover
                              20
                                        40         60         80

                                        Percent Ground Cover (%)
                                                                       100
                                                                                  120
                                  --- Reclaimed Sandy Loam
-Unmined Sandy Loam
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                              5-63

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Development Document - Western Alkaline Coal Mining Subcategory
Figure 5f: Navajo Mine Sediment Yield vs. Slope
Length

0.3 -
•o
~ 0.25 -
'c >>
1 1 0.2-
.£ o
"S 5
 g 0.15 -
ro S
3
c 01-
c
<
0.05 -I
0 -



m.--'
..--'"
..-
.-*
^-— * 	
^-"-"""^

^^"^
^^ 	 * 	
-•X- ' "
X----"" A -------*•*"""
0 50 100 150




,*-~


, 	
__— •• 	 	



., -X 	 *
	 x 	
	 A 	 "








-•



x

A














200 250 300 350
Slope Length (ft)
	 • 	 Unmined Sandy Loam; 10% Canopy; n = 0.03

---x--- Reclaimed Sandy Loam; 10%

Canopy; Furrow (0.1); n = 0.05




^
Yield (tons/acre/
c
15
3
C
C
<


Figure 5g: Navajo Mine Sediment Yield vs.
0.1 -,
0.09 .
0.08 -
0.07 -
0.06 -
0.05 ,
0.04 -
0.03 1
0.02 -
0.01 >
0 -
C
Depression Storage

^-,

< "x
\ X .


" " """--. . ^ ^^X
^X^"



0.1 0.2 0.3 0.4 0.5 0.6
Depression Storage (in)
-•--. Re
-* — Ur

mined Sandy Loam; n=0.03 — x 	 Unmined Sandy Loam; n = 0.05
5
5-64
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                                       Development Document -  Western Alkaline Coal Mining Subcategory
Figure 5h: M cKinley M ine Sediment Yield vs. Plot
0.3
? 0.25
•£
E -c- °'2
0) *0)
2 § 0.15
2 1
S o
3 - 0.1
1
i 0.05
0
C
Slope
A


,A- -X
^__.
,A , ^ ~~~~~~


x ^ — ~ - -









5 10 15 20 25 30 35 40
Plot Slope (percent)
— • — Unmined Loam; 10% Cover - -•- -Reclaimed Loam; 10% Cover; 0.1 Furrow

- -A- -Reclaimed Loam 10% Cover; No Furrow — • — Unmined Loam; 50% Cover
- -x- -Reclaimed Loam; 50% Cover


•o
I
Figure 51: M c Kin ley M ine Sediment Yields vs. Plot
0.5 ,
0.45
0.4
0.35 -
SI1
I -5

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Development Document - Western Alkaline Coal Mining Subcategory
                    Figure 5j:  M cKin ley M ine  Sed im ent Yield vs. S lope
                                              Length
              0.9
              0.7 -
           O  0.6 -
           •3  0.5 -
           S  °-4 H
           E
           T3  0.3 -
           ra  0.2 -
           c
           <  0.1 H
                           50
                                     100        150        200

                                             Slope Length (ft)
                                                                   250
                                                                             300
                                                                                       350
                       —•	Unmined Loam; 10% Cover           ...H. .. Reclaimed Loam; 10% Cover
                       -A--- Reclaimed Loam; 10% Cover; 0.1 Furrow s ---x--- Reclaimed Loam; 10% Cover; 0.3 Furrow s
                   Figure 5k:   M c Kin ley Mine Sediment Yield vs. Percent
                                           Gound Cover
                                         40          60          80

                                         Percentage Ground Cover
                                                                            100
                                                                                        120
                                — Reclaimed Loam; No Cover
                                                           -Unmined Loam; No Cover
5-66
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                                        Development Document - Western Alkaline Coal Mining Subcategory


"g 0.25 -
O *
re
to
0 0.2 -
•a
HI
£ °-15 '
HI
E
(/)
15
c 0 05 -


0 -
C



Figure 51: M c K in ley M ine Sediment Yield vs.
Depression Storage

^--..^
"•"*-- _ .^
*"-^_
""""•-••-..
**- ^
'"""•"--» '*^-^,


— ~~*~~~~— — ••--•-.
— — _* ~ - - . ^
"*~ ~. — . tj
'"" *** — . ij

0.1 0.2 0.3 0.4 0.5 0
Depression Storage (in)
— »--- Reclaimed Loam; 10% Cover; n=0.035 — • — Reclaimed Loam; 10% Cover; n=0.05
	 A 	 Unmined Loam; 10% Cover; n=0.035 	 * — Unmined Loam; 10% Cover; n=0.05
















6



                   Figure  5m:  Black M esa/Kayenta M ines Sediment Yield
                                           vs. Plot S lope
           f  °-6 ^
           o
           re
           "M  0.5 -
           O
            v   o.:
            E

            1   0.2  J
                                             15        20        25

                                             Plot S lope (percent)
                        -Unmined Loam; 10% Cover           -------Reclaimed Loam; 10% Cover
                        -Reclaimed Loam; 10%  Cover; 0.1 Furrow - --x-- - Rec laim ed Loam; 10% Cover; 0.3 Furrow
Case Studies
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Development Document - Western Alkaline Coal Mining Subcategory
Figure 5n: Black M esa/Kayen ta M
0.7 -,
0.6 -
S 0.5 -
Annual Sediment
(tons/acre/yr
o o o
K> CO £*
0.1 -
0 -
C
vs. Plot Slope


••^^^
* , - ' ^ — -•
A 	 	 - —
5 10 15 20
ines S ed im en t Yield


^^~~-~
__ - A
, A -


25 30 35 40
Plot S lope (percent)
	 * 	 Unmined Sandy Loam; 10% Cover
- -•- -Reclaimed Sandy Loam;
- -A- -Reclaimed Sandy Loam;
— f — Reclaimed Sandy Loam;
10% Cover
10% Cover; 0.1 Furrows
10% Cover; 0.3 Furrows
Fic

1 .2 -
^
c >
o a; 0.8 -
._ o
w 1 0.6 -
1 a
| 0.4 -
0 2
o
C




jure So: Black Mesa/Kayenta M ines Sedimer
Yield vs. Slope Length (ft)
,...--
,.-•*'
...-••"
.-•
.••
..-
.-•" 	 A
	 A 	
.-•" 	 A 	
f~ 	 A 	
%£ 	 -— *-
50 100 150 200 250 30t
Slope Length (ft)
» Unmined Sandy Loam; 10% Cover
...A — Reclaimed Sandy Loam; 10% Cover; 0.1 in. Fur rows
--x — Reclaimed Sandy Loam; 10% Cover; 0.3 in. Furrows
It









) 3J














0




5-68
Case Studies

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                                        Development Document - Western Alkaline Coal Mining Subcategory
          «
          o
          m
          '•5
                  Figure  5p:   Black  Mesa Mines  Sed im en t Y ield vs.
                                         Slope  Length
             0.6 -


             0.4 -


             0.2 -


              0
                                    100        150        200

                                            Slope Length (ft)
                 	Unmined Loam; 10% Cover             - - -•- - - Reclaimed Loam; 10% Cover
                 - — Reclaimed Loam; 10% Cover; 0.1 in. Furrow s ---X--- Reclaimed Loam; 10% Cover; 0.3 in. Furrow s
                Figure 5q:  Black Mesa/Kayenta Mines Sediment Yield vs.
                                    Percent Ground Cover
            0.45
                                       40          60          80

                                       Percentage Ground Cover
                        -«— Reclaimed Loam; No Cover
                        -A— Reclaimed Sandy Loam; No Cover
-Unmined Loam; No Cover
 Unmined Sandy Loam; No Cover
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Development Document - Western Alkaline Coal Mining Subcategory
5.5.5.1   Navajo Mine

       Model prediction results indicate that alternate sediment controls can be used to produce
sediment yields that are less than background or unmined conditions.  For example, an unmined
sandy loam of 15 percent slope and 10 percent vegetative cover density produces more sediment
than a reclaimed sandy loam of 25  percent slope and a 5 percent vegetative cover density if
furrows capable of retaining 0.1 inch of rainfall are present and slope lengths are equal (Figure
5d). It is important to note that these furrows are only a temporary measure and a more
permanent reclamation technique should be implemented.  An example of this would be using
rock or mulch as  a ground cover.

       Figure 5d also provides a comparison of pre-and post-mined sandy loams.  The figure
indicates that reclaimed sandy loams (post-mining) with vegetation (5 percent cover) but without
furrows results in higher sediment yields than unmined areas of similar soil/sand cover for any
slope.  Figure 5d also indicates that achievement of background sediment yields solely through
manipulation of slope gradient requires that the reclaimed slope gradient be significantly
reduced. For example, to maintain a reclaimed sediment yield comparable to that of an unmined
sandy loam on a 10 percent slope, the reclaimed slope not exceed 5 percent.

       The effects of varying ground cover on sediment yield for sandy loams are shown in
Figure 5e. A reclaimed sandy loam site would require significantly more ground cover to
produce the same sediment yield as an unmined sandy loam site. For example, a reclaimed
sandy loam soil with at least 60 percent ground cover would yield approximately the same
amount of sediment as unmined sandy soil with 20 percent ground cover.

       Figure 5f provides a comparison of sediment yields from pre- and post-mining sandy
loam sites based on slope lengths.  Based solely on slope length, reclaimed slope lengths should
be less than 50 feet to maintain background sediments yields for an unmined sandy loam site
with an original slope length of 100 feet.

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                                   Development Document - Western Alkaline Coal Mining Subcategory
       Figure 5g illustrates the effectiveness of furrows in reducing hillslope sediment yield.
Surfaces with furrows tend to be rougher and therefore have higher Manning n values than
surfaces without furrows. For computer modeling purposes, plots without furrows were given a
Manning n of 0.03 and plots with furrows were given values of 0.05.

5.5.5.2   McKinley Mine

       Similar to the Navajo Mine computer prediction results, Figure 5h shows that a
significant reduction in reclaimed slope gradient is required to maintain sediment yield below
background levels. Figure 5h also shows that reclaimed loam soil with 10 percent canopy cover
and furrows capable of retaining 0.1 inch of rainfall produces less sediment than an unmined
loam soil with 50 percent canopy cover. Figure 5i indicates that reduction of slope gradient by
itself would not be sufficient to reduce sediment yield below background levels with a sandy
loam soil at the McKinley Mine.  A reclaimed sandy loam soil with  a 50 percent canopy cover
and furrows capable of retaining 0.6 inches of rainfall will produce less sediment than an
unmined sandy loam with 10 percent canopy cover.

       The average annual sediment yield for reclaimed loam soils also was compared to
background conditions for different slope lengths, percentages of ground cover and amounts of
depression storage as shown in Figures 5j, 5k, and 51. Figure 5j shows that a 300-foot long
reclaimed loam  soil plot, with furrows capable of holding 0.1 inches of rainfall, produces less
sediment than an unmined 150-feet long loam soil plot.  Figure 5k illustrates that a reclaimed
loam soil with at least 60 percent ground cover will yield approximately as much sediment as an
unmined loam soil with 40 percent ground cover.  Figure 51 shows the effect of depression
storage and roughness on annual sediment yield.  Reclaimed soils are much more sensitive to the
amount of depression storage than unmined soils.  Also as can be seen from 51, a loam soil can
be temporarily reclaimed to meet the background sediment yield of an unmined loam soil with
0.1 inch of depression storage (n = 0.035).
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Development Document - Western Alkaline Coal Mining Subcategory
5.5.5.3   Black Mesa/Kayenta Mines

       Figures 5m and 5n show the sediment yield response of a loam soil and sandy loam soil
to changes in slope gradient for both pre- and post-mining conditions, respectively. Both figures
show that a modest 3 to 5 percent reduction in slope gradient can maintain sediment yields at or
below background levels. Also shown in both figures are the effects of contour furrows on
sediment yield.  Figure 5m shows that reclaiming loam soil with furrows that are capable of
retaining at least 0.1 inch of rainfall will satisfy the requirement of producing less sediment than
the amount produced by background conditions.  Reclaimed sandy loam soil requires furrows
capable of retaining 0.5 inches of rainfall to meet the background criteria as shown in Figure 5n.

       Figures 5o and 5p show the same results as Figures 5m and 5n, except that they include
slope length instead of plot slope.  Figure 5o shows that for sandy loam soils, decreasing the
slope length of the reclaimed area and reclaiming with furrows may be necessary to meet
background sediment yields.

       As shown in Figure 5q, for reclamation of loam and sandy loam soils that originally had
20 percent ground cover with rock mulch, a 30 percent ground cover and a 80 percent ground
cover would be necessary for the loam and sandy loam soils respectively.

5.5.5.4   Conclusions

       Comparisons were made between the erosion potential of reclaimed land versus
undisturbed hillslope surfaces.  In general, results of this evaluation tend to indicate that erosion
potential of reclaimed surfaces exceeds that of unmined lands, when all other conditions  are held
constant. The addition of contour furrows to the land surface tends to significantly reduce
erosion potential, however such features generally last only a few years. Contour furrows can
also tend to hinder seeding and revegetation efforts.

       More permanent forms of alternative sediment control practices include:

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                                    Development Document -  Western Alkaline Coal Mining Subcategory
              Manipulation of the slope gradient,
              Manipulation of slope length,
              Modification of the density of surface cover (vegetation, mulch, etc.),
              Alteration of the hillslope surface to increase roughness or depression storage,
              and
              Enhancement of infiltrative capacity of the soil.
       Evaluation of the first four sediment control alternatives listed above shows that these
alternatives generally can be used to meet the background performance standard.  Depending on
the specific properties of any particular site, defined by such variables as hillslope gradient and
length, cover density, soil particle size distribution and infiltration capacity, one or more of these
measures may be required for alternative sediment control to be effective. According to this
study, the recommended procedure for evaluation of alternative sediment control requires use of
the MULTSED model to define the background conditions of runoff and sediment yield for a
range of storm conditions. Modeling of the reclaimed conditions then indicates the relative
differences in runoff/erosion response resulting from mining activities. If post-mining erosion
exceeds the undisturbed erosion potential, MULTSED can be applied to evaluate the necessary
modifications to the watershed system to meet the background performance standard.
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                                  Development Document - Western Alkaline Coal Mining Subcategory
Section 6.0       References

Bridger Coal Company, 1987. Proposal for Determination of "Best Technology Currently
       Available" for Alternate Sediment Control Techniques at Bridger Coal Company.
       Submitted to Wyoming Department of Environmental Quality, Land Quality Division,
       Cheyenne, WY.

Carlson, K.E., W.R. Erickson, and R.C. Bonine, 1995.  High Intensity Short Duration Rotational
       Grazing on Reclaimed Cool Season Fescue/Legume Pastures: II. Forage Production, Soil
       and Plant Tissue Comparisons Between Grazed and Ungrazed Pastures. In Proceedings
       of the American Society for Surface Mining and Reclamation 12th Annual National
       Meeting, Gillette, WY, June 3-8, pp. 215-224.

Coal Age, 1998.  Keystone Coal Industry Manual, Intertec Publishing:Chicago, IL.

Doehring, D.O., and others, 1985. Impact of Surface Mining Sediment Control Regulation on
       the Hydrologic Balance of Dryland Streams. Presented at the Second Annual Meeting of
       the American Society for  Surface Mining and Reclamation, Denver, CO, Oct. 8-10.

Energy Information Administration, 1995.  Coal Data: A Reference, p. 57.

Energy Information Administration, 1997. Coal Industry Annual 1997. Washington DC,
       DOE/EIA -0584(97).

Erickson, W.R. and K.E. Carlson, 1995. High Intensity Short Duration Rotational Grazing on
       Reclaimed Cool Season Fescue/Legume Pastures: I.  System Development. In
       Proceedings of the American Society for Surface Mining and Reclamation 12th Annual
       National Meeting, Gillette, WY, June 3-8, pp. 202-214.

Hargis, N.E. and D.C. Hartley, 1995.  A Review of Reclamation and Alternate Sediment Control
       at Bridger Coal Company in Southwestern Wyoming. Presented at the National Meeting
       of the American Society for Surface Mining and Reclamation, Gillette, WY, June 5-8,
       pp. 409-415.

Heede, Burchard H., 1975. Stages of Development of Gullies in the West. Presented in Present
       and Prospective Technology for Predicting Sediment Yields and Sources, U.S.
       Department of Agriculture, ARS-S-40, New Orleans, LA.

Hjemfelt, A.T., L.A. Kramer, and R.G. Spomer.  1986. Role of Large Events in Average Soil
       Loss. In Proceedings of: The Fourth Federal  Interagency Sedimentation Conference,
       March 24-27 1986. Las Vegas, NV.
References                                                                           6-1

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Development Document - Western Alkaline Coal Mining Subcategory
Hromadka II, T.V., 1996.  Hydrologic Modeling for the Arid Southwest United States.
       Lighthouse Publications, Mission Viejo, CA.

Kleinbaum, D.G. and L.L. Kupper, 1978.  Applied Regression Analysis and Other Multivariate
       Methods, Duxbury Press, Boston, MA.

Montana Department of Environmental Quality, 1996.  Montana Sediment and Erosion Control
       Manual, Prepared by Roxann Lincoln, NPDES Storm Water Program, Revised May
       1996.

National Oceanic and Atmospheric Administration, 1998. Climatological Data Annual
       Summary for Montana, New Mexico, Arizona, Colorado, and Wyoming, v. 101-103 &
       107, no.13.

Pennsylvania Department of Environmental Protection, 1999. Engineering Manual for Mining
       Operations. Pennsylvania Bureaus of Mining and Reclamation and District Mining
       Operations, Document No. 563-0300-101, January 1999.

Peterson, M.R. and others, 1995. Application of a Watershed Computer to Assess Reclaimed
       Landform Stability in Support of Reclamation Liability Release.  Paper presented at the
       National Meeting of the American Society for Surface Mining and Reclamation, Gillette,
       WY, June 5-8.

Porterfied, G., 1972. Computation of Fluvial-Sediment Discharge. Publication No. TW13-C3,
       U.S. Geological Survey, Arlington,VA.

Renard, K.G., and others, 1997. Predicting Soil Erosion by Water: A Guide to Conservation
       Planning With the Revised Universal Soil Loss Equation (RUSLE). U.S. Dept. of
       Agriculture, Agriculture Handbook Number 703. Washington, DC.

Simons, Li & Associates, 1982. Design Manual for Sedimentation Control Through
       Sedimentation Ponds and Other Physical/Chemical Treatment. Washington, DC, Office
       of Surface Mining.

Toy, T. J., G.R. Foster, and J.R. Galetovic, 1998.  Guidelines for the Use of the Revised
       Universal Soil Loss Equation (RUSLE) Version 1.06 on Mined Lands, Construction
       Sites, and Reclaimed Lands. U.S. Office of Surface Mining, Denver, CO, August 1998.

U.S. Army Corps of Engineers, 1999. Hydrologic Engineering Center. HEC-6, Scour and
       Deposition in Rivers and Reservoirs.

U.S. Environmental Protection Agency, 1992.  Storm Water Management for Construction
       Activities, Developing Pollution Prevention Plans and Best Management Practices.
       Office of Water, Publication No. EPA 832-R-92-005, September 1992.
6-2                                                                           References

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                                   Development Document - Western Alkaline Coal Mining Subcategory
U.S. Environmental Protection Agency, 1998. Water Quality Criteria and Standards
       Plan-Priorities for the Future. Office of Water. EPA Document #822-R-98-003.

U.S. Geological Survey,  1996. Coal Resource Regions in the Conterminous United States,
       Open File Report 96-279.

U.S. Mining and Reclamation Council of America, 1985. Handbook of Alternative Sediment
       Control Methodologies for Mined Lands, U.S. Office of Surface Mining, Washington,
       DC.

Warner, R.C. and P.J. Schwab, 1998. SEDCAD 4 for Windows 95 & NT-Design Manual and
       User's Guide. Civil Software Design, Ames, IA.

Water Engineering & Technology, Inc., 1990. Determination of Background Sediment Yield
       and Development of a Methodology for Assessing Alternative Sediment Control
       Technology at Surface Mines in the Semi-arid West. Fort Collins, CO.

Western Coal Mining Work Group, 1999a. Technical Information Package: Western Alkaline
       Mining Subcategory. Prepared for the Western Coal Mining Work Group by Habitat
       Management, Inc., Littleton, CO, January 1999.

Western Coal Mining Work Group, 1999b.  Data Submittal: Western Alkaline Mining
       Subcategory. Washington, DC. (Data in Section 3.3.2 of Coal Industry Record)

Western Coal Mining Work Group, 1999c. Western Alkaline Mining Subcategory Mine
       Modeling and Performance-Cost-Benefit Analysis, Draft. Prepared for the Western Coal
       Mining Work Group by Habitat Management, Inc. and Water & Earth Technologies, Inc.,
       Littleton, CO, June 1999.

Western Coal Mining Work Group, 2000a. Western Alkaline Coal Mining Subcategory
       Modeling of Intermountain and Northern Plains Region, Draft. Prepared for the Western
       Coal Mining Work Group, September 26, 2000.

Western Coal Mining Work Group, 2000b. Western Alkaline Coal Mining Subcategory
       Modeling of Premining Activities Supporting Reclamation and Performance-Cost-
       Benefit Analysis, Draft. Prepared for the Western Coal Mining Work Group by Habitat
       Management, Inc. and Water & Earth Technologies, Inc.,  September 6,  2000.

Western Coal Mining Work Group, 2001. Western Alkaline Coal  Mining Subcategory
       Intermountain and Northern Plains Region Economic Analysis Addendum, Draft.
       Prepared for the Western Coal Mining Work Group by Habitat Management, Inc., April
       30,2001.

Williams, G.P.  and M.G. Wolman, 1984. Downstream Effects of Dams on Alluvial Rivers.
       U.S. Geological Survey Professional Paper 1206, U.S. Government Printing Office,

References                                                                            6-3

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Development Document - Western Alkaline Coal Mining Subcategory
       Washington, DC.

Wilson, B.N., BJ. Barfield, A.D. Ward, and ID. Moore. 1984. A Hydrology and Sedimentology
       Watershed Model, Part I: Operational Format and Hydrologic Component. Transactions
       of the ASAE 27(5): 1370-1377.
6-4                                                                            References

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                            Development Document - Western Alkaline Coal Mining Sub category
Appendix A:   Wyoming Coal Rules and Regulations, Chapter IV
Appendix A

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                                                                                        Appendix A

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                                   Development Document - Western Alkaline Coal Mining Sub category
                                      CHAPTER 4

          ENVIRONMENTAL PROTECTION PERFORMANCE STANDARDS

                    FOR SURFACE COAL MINING OPERATIONS

       Section 1. General.

       This Chapter sets forth the environmental protection performance standards applicable to
all coal mining operations. No mining operation shall be conducted except in compliance with
the requirements hereof.

       Section 2. General Environmental Protection Performance Standards.

       (a)     Land uses.

              (i)    Reclamation shall restore the land to a condition equal to or greater than
the "highest previous use." The land, after reclamation, must be suitable for the previous use
which was of the greatest economic or social value to the community area, or must have a use
which is of more economic or social value than all of the other previous uses.

              (ii)    Operators are required to restore wildlife habitat, whenever the
Administrator determines that this restoration is possible, on affected land in a manner
commensurate with or superior to habitat conditions which existed before the land became
affected, unless the land is private and the proposed use is for a residential or agricultural
purpose which may preclude its use as wildlife habitat.

              (iii)   Water impoundments used for recreational purposes shall be constructed
in accordance with the statutes and (g) of this Section. Recreational lands, other than water
impoundments, represent changes in the land which may or may not be suitable for wildlife
habitat.

       (b)     Backfilling, grading and contouring.

              (i)    Rough backfilling and grading shall follow coal removal as
contemporaneously as possible based upon the mining conditions. The operator shall include
within the application for a permit to mine a proposed schedule for backfilling and grading with
supporting analysis.

              (ii)    Backfilled materials shall be replaced in a manner which minimizes water
pollution on and off the site and supports the approved postmining land use.


Preparation  of final graded surfaces shall be conducted  in a manner that minimizes erosion and

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provides a surface for replacement of topsoil that will minimize slippage.

              (iii)   All affected lands shall be returned to their approximate original contour,
except as authorized by a variance or exemption under Chapter 5, Sections 6 and 7, or Chapter 8,
or Chapter 9.

              (iv)   All spoil shall be transported, backfilled, compacted (where necessary to
insure stability or to prevent leaching) and graded to eliminate all highwalls, spoil piles,  and
depressions, except  that:

                    (A)   Soil conservation techniques may be employed if they are needed to
retain moisture, minimize erosion, create and enhance wildlife habitat, and assist revegetation.

                    (B)    Incomplete elimination of highwalls may be authorized in accordance
with Chapter 5, Section 7.

                    (C)    Spoil may be placed on an area outside the mined-out area to restore
the approximate original contour by blending the spoil into the surrounding terrain if the spoil is
backfilled and graded on the area in accordance with the requirements of this subsection.

              (v)   Postmining slopes shall not exceed a slope necessary to achieve a minimum
long-term static safety factor of 1.3, to prevent slides and restore stable drainages and hillslopes.

              (vi)   Thin overburden.  Where surface coal mining operations are proposed to be
carried out continuously in the same limited pit area for more than  one year from the day coal
removal operations begin and where the volume of all available spoil  and suitable waste materials
over the  life  of the  mine is demonstrated to be insufficient to achieve the approximate original
contour considering bulking factor and coal removal, surface mining activities shall be conducted
to use all available spoil and suitable waste materials to attain the lowest practicable stable grade,
but not more than the angle of repose, and to meet the requirements of paragraphs (ii) and  (iv)
above.

              (vii)   Thick overburden. Where the volume of spoil over the life of the mine is
demonstrated to be more than sufficient to achieve the approximate original contours considering
bulking factor, coal removal and  subsidence of backfilled material,  excess spoil  may be placed
outside the pit area in accordance with the requirements of subsection (c).

              (viii) Permanent impoundments: Where permanent impoundments are authorized
in accordance with Chapter 2, Section  2(b)(xiv), spoil that may result from the impoundment will
be handled in accordance with the requirements of this subsection.

              (ix)   Soft rock surface mining.

                    (A)   If the reclamation plan  does  not provide for a  permanent water
impoundment, the final pit area shall be backfilled, graded, compacted and contoured to the extent

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                                    Development Document - Western Alkaline Coal Mining Sub category
necessary to return the land to the use specified in the approved plan.  In preparation of slope
specifications  in the plan, the operator shall consider an  average of the measured slopes in the
immediate area of the proposed mine site.  Slopes in the reclaimed area shall approximate the
premining slopes. Individual slope measurements, locations of the measurements, and the average
measurement shall be submitted with the reclamation plan. In determinations of the approximate
premining slope, the Land Quality Division may make an independent slope survey. All backfilling,
grading, and contouring will be done in such a manner so as to preserve the original drainage or
provide for approved adequate substitutes. No depressions to accumulate water will be permitted
unless approved in the reclamation plan as being consistent with the proposed future use of the land.

                     (B)     Terraces or benches may be used  only when it can be shown to the
Administrator's satisfaction that other methods of contouring will not provide the required result.
If terracing is proposed, detailed plans indicating the dimensions and design of the terraces, check
dams, any erosion prevention techniques, and slopes of the terraces  and their intervals  will be
required.

                     (C)     If the reclamation plan provides for a permanent water impoundment
and this use has  been approved according  to the requirements outlined in the Act and these
regulations, the exposed pit areas must be sloped, graded, and contoured so as to blend in with the
topography of the surrounding terrain and provide for access and revegetation.  Riprapping where
necessary to prevent erosion will be required.  Sloping requirements will be as described above.
Under certain conditions wherein it can be demonstrated to the Administrator's satisfaction that the
pitwall can be stabilized by terracing or other techniques it may be permissible to leave not more
than one-half of a proposed shoreline composed of the stabilized pitwall.  The remaining portion of
the shoreline must be graded and contoured so as to provide access and blend in with the topography
of the surrounding terrain. In the event that a partial pitwall is proposed as final reclamation, the
operator must submit a detailed explanation of the techniques to be used to establish the stability of
the pitwalls in his reclamation plan.  At the Administrator's discretion, a study of the proposed
pitwall  stabilization techniques may be required from an independent engineering company for
purposes of verifying the effectiveness of the proposed stabilization techniques. The Land  Quality
Division will determine the acceptability of the proposed stabilization techniques based on this
information and an on-site inspection.

                     (D)     Highwall retention may be considered on a case-by-case basis for
enhanced  wildlife habitat.  The Wyoming Game and Fish Department shall be consulted by the
applicant for need and design of the land form. Any approval under this paragraph shall be based
on a demonstration of safety, stability, environmental protection, and  equal or better land use
considerations.

       (c)    Topsoil, subsoil, overburden, and refuse.

              (i)     Topsoil.

                     (A)     All topsoil or approved surface material shall be removed from all
areas to be affected in the permit area prior to these areas being affected unless otherwise authorized

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Development Document - Western Alkaline Coal Mining Sub category
by the Administrator.  The topsoil may be mixed with the subsoil but shall be segregated so as not
to become mixed with spoil or waste material, stockpiled in the most advantageous manner and
saved for reclamation purposes. The Administrator may authorize topsoil to remain on areas where
minor disturbance will occur associated with construction and installation activities including but
not limited to light-use roads, signs, utility lines, fences, monitoring stations and drilling provided
that the minor disturbance will not destroy the protective vegetative cover, increase erosion,  nor
adversely affect the soil resource.

                     (B)    When topsoil is not promptly redistributed, the topsoil or approved
surface material shall be stockpiled on stable areas within the permit area in such a manner so as to
minimize wind and water erosion and unnecessary compaction. In order to accomplish this, the
operator shall establish, through planting or other acceptable means, a quick growing cover of
vegetation on the topsoil stockpiles. The topsoil shall also be protected from acid or toxic materials,
and shall be preserved in a usable condition for sustaining vegetation when placed over affected
land.  Provided however, where long-term disturbance will occur, the Administrator may authorize
the temporary distribution of topsoil to enhance stabilization of affected lands within the permit area.
Where this is authorized, the Administrator shall  find that the topsoil or subsoil capacity and
productive capabilities are not diminished, that the topsoil is protected from erosion, and will be
available for reclamation.

                     (C)    Reclamation shall  follow mining as soon as is feasible so as to
minimize the amount  of time topsoil must be stockpiled.  Where topsoil has been stockpiled for
more than one year, the operator may be required to conduct nutrient analyses to determine if soil
amendments are necessary.

                     (D)    Topsoil stockpiles  shall be  marked with a legible sign containing
letters not less than six inches high on all approach roads to such stockpiles. Said signs shall contain
the word "Topsoil" and shall be placed not more than 150 feet from any and all stockpiles of topsoil.
Such signs must be in place at the time stockpiling is begun.

                     (E)    If abundant topsoil is present, and it is not all needed to accomplish
the reclamation required in the approved reclamation plan, the Administrator may approve of use
of this topsoil by this or another operator in another area for reclamation purposes.

                     (F)    Trees, large rocks and other  waste material which  may hinder
redistribution of topsoil shall be separated from the topsoil before stockpiling.

              (ii)    Subsoil.

                     (A)    Except as provided in (B), all subsoil determined by field methods or
chemical analysis to be suitable as a plant-growth medium shall be removed from all areas to be
affected and handled in accordance with the topsoil requirements of this Section.

                     (B)    Upon an adequate demonstration by the operator that all or a portion
of the subsoil material is not needed to meet the  revegetation and land use requirements of these

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                                    Development Document - Western Alkaline Coal Mining Sub category
regulations, the Administrator may authorize all or a portion of the subsoil to not be used for
reclamation.  The unused subsoil may then be regarded as overburden material and handled in
accordance with the requirements of this Section.

              (iii)   The topsoil (A and E horizons) shall be segregated from the subsoil (B and
C horizons) where the Administrator determines that this practice is  necessary  to achieve the
revegetation requirements of these regulations.

              (iv)   Before redistribution of topsoil or subsoil the regraded land shall be treated,
if necessary, to reduce potential for slippage and encourage root penetration.

              (v)    Topsoil, subsoil, and/or an approved topsoil substitute shall be redistributed
in a manner that:

                     (A)    Achieves an approximate uniform, stable thickness consistent with the
approved permit and the approved postmining land uses, contours and surface water drainage
system;

                     (B)    Prevents compaction which would inhibit water infiltration and plant
growth;

                     (C)    Protects the topsoil from wind and water erosion before and after it
is seeded until vegetation has become adequately established; and

                     (D)    Conserves soil moisture and promotes revegetation.

              (vi)   All  rills and gullies which either preclude  achievement of the approved
postmining land use or the reestablishment of the vegetative cover, or cause or contribute to a
violation of water quality standards for the receiving  stream, shall  be regraded or otherwise
stabilized. Topsoil shall be replaced and the areas shall be reseeded or replanted.

              (vii)   Nutrients and soil amendments in the amounts determined necessary by soil
test or field trials shall be applied to the replaced topsoil, subsoil or substitute material so that
adequate nutrient levels are available to  establish the vegetative cover.  Fertilizer shall be applied
at  appropriate  seasons and  in amounts that will minimize pollution  of surface  waters or
groundwaters.

              (viii)  The Administrator may not require  topsoil or subsoil replacement  on
structures or within impoundments where replacement  of this material is inconsistent with the
intended use and the structures are otherwise stable.

              (ix)   If a sufficient volume of suitable topsoil or subsoil is not available for salvage
or redistribution, then selected spoil material may  be used as a topsoil or subsoil substitute or
supplement. The operator shall demonstrate that the resulting plant growth medium is equal to, or
more suitable for sustaining vegetation  than the existing topsoil or subsoil and  that it is the best

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Development Document - Western Alkaline Coal Mining Sub category
available in the permit area to support revegetation.  A demonstration of the suitability of the
substitutes or supplements shall be based upon analysis of the texture, percent coarse fragments and
pH.  The Administrator may require other chemical and physical analyses, field site trials, or
greenhouse tests if determined to be necessary or desirable to demonstrate the suitability of the
topsoil or subsoil substitutes or supplements.

              (x)    Topsoil  and subsoil substitutes.

                     (A)   Topsoil substitute stockpiles shall be segregated from topsoil and
overburden piles and shall be identified as substitute material.  Identification signs shall be placed
not more than 150 feet from all stockpiles of substitute material. Such signs shall be in place at the
time stockpiling is begun.

                     (B)   If overburden is to be used in reclamation as a substitute for topsoil,
all large rocks and other waste material which may hinder redistribution shall be separated before
stockpiling.

              (xi)    Overburden, spoil and refuse.

                     (A)   All overburden, spoil material and refuse shall be segregated from the
topsoil and subsoil and stockpiled in such a manner to facilitate the earliest reclamation consistent
with the approved reclamation plan.

                     (B)   Except where  diversions are authorized by these  regulations,  all
overburden, spoil material,  and refuse piles  must be located to avoid blocking intermittent or
perennial drainages and flood plains in order to minimize loss  and spread of material due to water
erosion. Ephemeral drainages may be blocked if environmentally sound methods for dealing with
runoff control and sedimentation are  approved by the Administrator.

                           (I)     For temporary stockpiles, material should be replaced in pits
as soon as possible consistent with the approved reclamation plan to minimize the amount of time
material is stockpiled.

                     (C)   All topsoil shall be removed from areas to be used for piling  spoil
material prior to the beginning of piling this material.

                     (D)   The operator may be required to have analyses made of spoil material
in order to determine if it will be a source of water pollution through reaction with leaching  by
surface water. If it is determined that this condition may exist, the operator shall describe proposed
procedures for eliminating this condition.

                     (E)   All overburden and spoil material that is  determined to be toxic, acid-
forming or will prevent adequate reestablishment of vegetation on the reclaimed land surface, unless
such materials occur naturally on the land surface, must be properly disposed of during the mining
operation.

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                                    Development Document - Western Alkaline Coal Mining Sub category
                     (F)    All excess spoil shall be placed in approved excess spoil disposal sites
located within the permit area. If permanent overburden, spoil, or refuse piles have been approved
by the Administrator, they shall be:

                            (I)     Located on  moderately sloping  and naturally stable areas
where placement provides for stability and prevents mass movement.

                            (II)    Located in areas which do not contain springs, seeps, natural
or man-made drainages (excluding rills and gullies), croplands, or important wildlife habitat.

                            (Ill)   Designed, graded and contoured so as to blend in with the
topography of the surrounding terrain. Excess spoil pile sites shall not be located on an overall slope
that exceeds 20 degrees unless keyway cuts (excavations to stable bedrock), rock toe buttresses or
other special structural provisions are  constructed to  ensure fill  stability.   The operator must
demonstrate to the satisfaction of the Administrator that this material will be stable and can be
revegetated as required by this Section.

                            (IV)   The slopes of all spoil areas must be designed so that they will
be stabilized against wind and water erosion. After the grading and contouring of these stockpiles,
topsoil or  approved subsoil must be distributed  over  them in preparation for the revegetation
procedure. Revegetation must be completed in accordance with requirements of this Chapter. A
permanent drainage system must be established consistent with these regulations.

                     (G)    Excess  spoil may be returned to underground mine workings in
accordance with the plan approved by the Administrator and by MSHA.

                     (H)    Excess spoil piles shall be designed using current, prudent professional
standards and certified by a qualified registered professional engineer.  All piles shall be designed
and constructed in accordance with the standards of this subsection. Special structural provisions
shall be designed using prudent current engineering practices, in accordance with Chapter 2, Section
                     (I)     Excess spoil shall be placed in a controlled manner to:

                            (I)     Prevent pollution from leachate and surface runoff from the
fill on surface water or groundwater of the State.
                            (II)    Ensure mass stability and prevent mass movement during and
after construction and provide for stable drainages and hillslopes.

                            (Ill)   Ensure that the land mass designated as the disposal site is
suitable for reclamation and revegetation compatible with the natural surroundings and approved
postmining land use.

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Development Document - Western Alkaline Coal Mining Sub category
                     (J)     The spoil pile shall be transported and placed in horizontal lifts in a
controlled manner, concurrently compacted as necessary to ensure mass stability and prevent mass
movement, covered, and graded to allow surface and subsurface drainage to be compatible with the
natural surroundings and ensure a minimum long-term static safety factor of 1.5.  The Administrator
may limit the horizontal lifts to four feet or less as necessary to ensure the stability of the fill  or to
meet other applicable requirements.

                     (K)    No water impoundments or large depressions shall be constructed on
the fill.  Soil conservation techniques may be approved if they are needed to minimize erosion,
enhance wildlife habitat or assist revegetation, as long as they are not incompatible with the stability
of the fill.

                     (L)    The foundation and abutments of the fill shall be stable under all
conditions of construction. Sufficient foundation investigation and any necessary laboratory testing
of foundation materials shall be performed in order to determine the design requirements for
foundation stability. Analyses of foundation conditions shall include the effect of underground mine
workings, if any, upon the stability of the structure.

                     (M)    Slope protection shall be provided to  minimize surface erosion at the
site. Diversion of surface water runoff shall conform with the requirements of subsection (e) of this
Section. All disturbed areas, including diversion  ditches that are not riprapped, shall be vegetated
upon completion of construction.

                     (N)    Terraces may be constructed on the outslope of the fill if required for
stability, control of erosion, to conserve soil moisture, or to facilitate the approved postmining land
use. The grade of the outslope between terrace benches shall not be steeper than 2h:lv (50 percent).

                     (O)    Excess spoil that is toxic, acid-forming or combustible shall be
adequately covered with suitable material or treated to prevent pollution of surface and groundwater,
to prevent sustained combustion, and to minimize  adverse affects on plant growth and the approved
postmining land use.

                     (P)    The Administrator may specify additional design criteria on a case-by-
case basis as necessary to meet the general requirements of this subsection.

                     (Q)    The fill shall be inspected for  stability by a qualified registered
professional engineer or other qualified professional specialist under the direction of a professional
engineer experienced in  the  construction of earth and rockfill embankments  at least quarterly
throughout construction and  during the following critical construction periods:  (1) foundation
preparation, including the removal of all organic  material and topsoil, (2) placement of diversion
systems, (3) installation of final surface drainage systems, and (4)  final grading and revegetation.
Regular inspections by  the  engineer or  specialist shall be  conducted during  placement and
compaction of the fill materials.   The registered professional engineer shall promptly provide
certified reports to the Administrator which demonstrate that the fill has been maintained and
constructed as specified in the design contained in the approved mining and reclamation plan. The

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                                    Development Document - Western Alkaline Coal Mining Sub category
report shall discuss appearances of instability, structural weakness, and other hazardous conditions.
A copy of all inspection reports shall be retained at the mine site.

              (xii)   Coal mine waste.

                     (A)    Coal mine waste shall be disposed only in existing or, if new, in an
approved disposal site within a permit area.  Coal mine wastes shall not be used in the construction
of dams, embankments, or diversion structures. The disposal area shall be designed, constructed and
maintained:

                            (I)     In accordance with the excess spoil disposal requirements of
(xi)(F)-(I), and (K)-(O) above; and

                            (II)    To prevent combustion and not create a public health hazard.

                     (B)    Disposal  of coal mine waste in excess spoil piles may be approved if
such waste is:

                            (I)     Placed in accordance with the excess spoil requirements of (xi)
above;

                            (II)    Demonstrated to be nontoxic and nonacid-forming (or properly
treated); and

                            (III)   Demonstrated to be consistent with the design stability of the
fill.

                     (C)    In addition to (A)  above,  coal  mine waste piles  shall meet the
following requirements:

                            (I)     The disposal facility shall be designed to attain a minimum
static safety factor of 1.5.  The foundation  and abutments must be stable under all  conditions of
construction.

                            (II)    Following final grading of the waste pile, the site shall be
covered with a minimum of four feet of the best available, nontoxic, nonacid-forming and
noncombustible material, in a manner that directs runoff away from the waste pile. The site shall be
revegetated in accordance with this Chapter.  The Administrator may allow less than four feet of
cover material based on physical and chemical analyses  which  show that the revegetation
requirements will be met.

                            (Ill)   Surface drainage from above the pile and from the crest and
face of the pile shall be permanently diverted around the waste in accordance with subsection (e)
of this Section.
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                           (IV)   All coal mine waste piles shall be inspected in accordance with
the excess spoil requirements of (xi) above. More frequent inspections shall be conducted if a
danger or harm exists to the public health and safety or the environment. Inspections shall continue
until the waste pile has been finally graded and revegetated or until a later time as required by the
Administrator. If any inspection discloses that a potential hazard exists, the Administrator shall be
notified immediately, including notification of any emergency protection and remedial procedures
which will be implemented. If adequate procedures cannot be formulated or implemented, the
Administrator shall inform the appropriate emergency agencies of the hazard to protect the public
from the  area.

                           (V)    All coal mine waste piles shall meet the  requirements of 30
CFR§§ 77.214 and 77.215.

                     (D)   Dams and embankments constructed to impound coal mine waste shall
comply with the following:

                           (I)     Each impounding structure shall be designed, constructed and
maintained in accordance with the requirements applicable to temporary impoundments.  Such
structures may not be retained permanently as part of the approved postmining land use. Approval
by the State Engineer's Office is not required.

                           (II)    If the impounding structure meets the criteria of 30 CFR §
77.216 (a), the combination of principal and emergency spillways shall be able to safely pass the
100-year, 6-hour design precipitation event or a storm duration having a greater peak flow.

                           (Ill)   Spillways and outlet structures shall be designed to provide
adequate protection against erosion and corrosion. Inlets shall be protected against blockage.

                           (IV)   Be designed so that 90 percent or more  of the water stored
during the design precipitation event can be removed within ten days.

                           (V)    Runoff from areas above the disposal facility or runoff from
the surface of the facility that may cause instability or erosion of the impounding structure shall be
diverted into  stabilized diversion channels designed to  meet the requirements  for diversions, and
designed to safely pass the runoff from a 100-year, 6-hour design  precipitation  event or a  storm
duration having a greater peak flow.

                     (E)   The Administrator may specify additional design criteria for  waste
piles or impounding structures on a case-by-case basis as necessary to meet the general performance
standards of this subsection.

                     (F)   Coal  mine waste  fires shall be extinguished by the  operator in
accordance with  a plan approved by the Administrator  and the Mine Safety  and Health
Administration. The plan shall contain, at a minimum, provisions to ensure that only those persons
authorized by the operator, and who have an understanding of the procedures to be used, shall be

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                                    Development Document - Western Alkaline Coal Mining Sub category
involved in the extinguishing operations. No burning or burned coal mine waste may be removed
from  a  permitted  disposal area  without a  removal plan  approved by the  Administrator.
Consideration shall be given to persons working or living in the vicinity of the structure.

                    (G)   Coal preparation plants shall be included within a permit area. Refer
to Chapter 3, Section 6 for requirements applicable to coal preparation plants.

              (xiii) Acid-forming and toxic materials, and other waste.

                    (A)   All exposed coal seams remaining after mining and any acid-forming,
toxic, and combustible materials, or any waste materials that are exposed, used or produced during
mining shall be adequately covered, within 30 days of its exposure with nontoxic, nonacid-forming
and noncombustible material, or treated.  Compaction followed by burial  or treatment shall be
provided to prevent pollution of surface and groundwater quality, prevent sustained combustion and
to minimize adverse effects on  plant growth and postmining land uses.  Such materials may be
stored in a controlled manner until final burial  and/or treatment first becomes feasible as long as
storage will not result in any risk of water pollution or other environmental or public health and
safety damage. Storage, final burial and treatment shall be done in accordance with all local, State
and Federal requirements.

                    (B)   Acid-forming or toxic material, or any other waste material capable
of polluting water, shall not be buried or stored in the proximity of a drainage channel or its flood
plain  so as to cause or pose a threat of water pollution.

                    (C)   Final  burial  of noncoal  mine waste materials  (such as  grease,
lubricants, paints, flammable liquids, garbage, trash, abandoned mining machinery, lumber and other
combustible materials) and any wastes classified as hazardous shall be in a designated disposal site
authorized by the Solid Waste Management Section of the Department.

                    (D)    Management and final burial  on the permit area of solid wastes
generated by a mine mouth power plant or mine mouth coal drier shall be in accordance with this
Section and with provisions of the Solid Waste  Management  Rules  and Regulations deemed
appropriate by the Administrator.

       (d)    Revegetation.

              (i)    The  operator shall establish on all affected lands a diverse, permanent
vegetative cover of the same seasonal variety native to the area or a mixture of species that will
support the approved postmining land use  in a manner consistent with the approved reclamation
plan.  This cover shall be self-renewing and capable of stabilizing the soil.

              (ii)   Land which did not support vegetation prior to becoming affected land
because of natural soil conditions need not be revegetated unless subsoil from such affected land will
support vegetation.  The  operator shall  demonstrate to the Administrator's  satisfaction that
revegetation or reforestation is  not possible if he seeks to proceed under the provisions of the

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subsection.

              (iii)    After backfilling, grading, and contouring and the replacement of topsoil,
and/or approved substitutes, revegetation shall be commenced in such a manner so as  to most
efficiently accommodate the retention of moisture and control erosion on all affected lands to be
revegetated. In addition, any fertilizer requirements as determined on the basis of previous analysis
must be fulfilled.

              (iv)    Mulch or other equivalent procedures which will control erosion and enhance
soil moisture conditions shall be used on all retopsoiled areas.

              (v)     Seeding which is accomplished by mechanical drilling  shall be on the
topographic contour, unless for safety reasons it is not practicable, or perpendicular to the prevailing
wind on flat areas.  Seeding of affected lands shall be conducted during the first normal period for
favorable planting conditions after final preparation unless an alternative plan is approved. Any rills
or gullies that would preclude successful establishment of vegetation or achievement of postmining
land use shall be removed or stabilized.  The species of vegetation to be used in revegetation efforts
shall be described in  the reclamation plan indicating the composition of seed mixtures  and the
amount of seed to be  distributed on the area on a per acre basis. Seed types will depend on the
climatic and  soil conditions prevailing in the permit  area and the proposed use  of the land  after
reclamation.  Species to be planted as permanent cover shall be self-renewing. Seeding rates will
depend on seed types, climatic and soil conditions and the techniques to be used in seeding.

              (vi)    Introduced  species may be used  only to achieve  a  quick, temporary,
stabilizing  cover to control erosion, or to achieve a postmining land use as approved by the
Administrator. Naturalized or nonindigenous native plant species may be included in the approved
seed mixture if they support the approved postmining land uses.  The operator shall document,
unless otherwise authorized by the Administrator, the suitability of these species using data from
published literature, from experimental test plots, from on-site experience, or from other information
sources.
              (vii)   When   the   approved   postmining   land  use   is   for  residential,
industrial/commercial, or cropland, the reclaimed area shall be stabilized and revegetated to control
erosion unless development or cropping shall immediately occur.

              (viii) For areas previously disturbed by mining and not reclaimed to the requirements
of these regulations, the areas shall, at a minimum, be revegetated to a ground cover and productivity
level existing before redisturbance and shall be adequate to control erosion.

              (ix)    Bond release. The bond for revegetation shall be retained for not less than
ten years after the operator has completed seeding, fertilizing, irrigation, or other work to ensure
revegetation.  The bonding period shall not  be affected where normal  and reasonably good
husbandry  practices  are being followed.  The success of revegetation shall be  determined in
accordance with Section 2(d)(x) of this Chapter and paragraphs (E)-(H) below. If the Administrator

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                                    Development Document - Western Alkaline Coal Mining Sub category
approves an alternative success standard, as allowed by Section 2(d)(x) of this Chapter, the standard
shall be based on technical information obtained from a recognized authority (e.g. Soil Conservation
Service, Agricultural Research Service, Universities,  Wyoming Game and Fish Department, U.S.
Fish and Wildlife Service,  etc.), or be supported by scientifically valid research.  Use  of an
alternative technical standard shall be supported by concurrence from State and Federal  agencies
having an interest in management of the affected lands.

              (x)     The Administrator shall not release the entire bond of any operator until such
time as revegetation is completed, if revegetation is the method of reclamation as specified in the
operator's approved reclamation plan. Revegetation shall be deemed to be complete when:  (1) the
vegetation cover of the affected land is shown to be capable  of renewing  itself under natural
conditions prevailing at the site, and the vegetative cover and total ground cover are at least equal
to the cover on the area before mining, (2) the productivity is at least equal to the productivity on
the area before mining, (3)  the species  diversity and composition are suitable for the approved
postmining land use and the revegetated area is capable of withstanding  grazing pressure at least
comparable to that which the land could have sustained prior to mining, unless Federal, State or
local regulations prohibit grazing on such lands, and (4) the requirements in (1), (2) and (3) are met
for the last two  consecutive years  of the  bonding period.   The  Administrator  shall specify
quantitative methods and procedures for determining whether equal cover and productivity has been
established including, where applicable, procedures for evaluating postmining species diversity and
composition.    The following  options  or  an  alternative  success standard approved by  the
Administrator are available:

                     (A)    The method utilizing control areas may be selected. If selected, the
control areas shall be sampled for cover, productivity, species diversity and composition in the same
season that the area to be  affected is sampled for  baseline data.  Quantitative premining and
postmining vegetation data from the control areas shall be used to mathematically adjust premining
affected area  data for climatic change. Premining affected area cover and  productivity data will be
directly compared by  statistical procedures to  data  from the reclaimed vegetation type  when
evaluating revegetation success for final bond release. Species diversity and composition data will
be qualitatively or quantitatively evaluated as determined by the Administrator.

                     (B)    The method utilizing reference areas may be selected. If selected, the
representativeness of the reference area  is verified by a statistical comparison to the plant
community that it typifies.  Postmining cover and productivity data from the reference area are
directly compared by standard statistical procedures to  data from the reclaimed area when evaluating
revegetation  success for final bond release.  Species diversity and composition data will be
qualitatively or quantitatively evaluated as determined by the Administrator.

                     (C)    Where the premining  cover, productivity, species diversity and
composition data cannot be collected, or where the area to be affected is small  and incidental to the
operation, comparison areas may be selected. For purposes of this method, postmining qualitative
and quantitative data from the comparison area are directly compared by procedures acceptable to
the Administrator to data from the reclaimed lands when evaluating success of revegetation for final
bond release.

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Development Document - Western Alkaline Coal Mining Sub category
                     (D)   Without regard to the type of method selected, control, reference or
comparison areas should be at least two acres in size, located in areas where they will not be affected
by future mining, while serving their designated use, managed in a fashion which will not cause
significant changes in the vegetation parameters of cover,  productivity, species diversity and
composition and be representative of the postmining land use.

                     (E)   The postmining density, composition, and distribution of shrubs shall
be based upon site-specific evaluation of premining vegetation and wildlife use. Shrub reclamation
procedures shall be conducted through the application of best technology currently available.

                           (I)    Except where a lesser density is justified from premining
conditions in accordance with Appendix A, at least 20 percent of the eligible lands shall be restored
to shrub patches supporting an average density of one shrub per square meter. Patches shall be no
less than .05 acres each and shall be arranged in a mosaic that will optimize habitat interspersion and
edge effect. Criteria and procedures for establishing the standard are specified in Appendix A. This
standard shall apply to all lands affected after August 6, 1996.

                           (II)    Approved shrub  species and seeding techniques  shall be
applied to all remaining grazingland. Trees shall be returned to a density equal to the premining
conditions.

                           (Ill)   For areas containing crucial habitat, designated as such prior
to the  submittal of a permit application or any  subsequent amendment, or  critical habitat the
Wyoming Game and Fish Department shall be consulted about, and its approval shall be  required
for, minimum stocking and planting arrangements of shrubs, including species composition.  For
areas determined to  be important habitat, the Wyoming Game  and Fish  Department  shall be
consulted  for recommended minimum stocking and planting arrangements of shrubs, including
species composition, that may exceed the programmatic standard discussed above.

                     (F)   Where trees are part of the approved reclamation plan, at the time of
bond release the trees to meet the required stocking rate shall be healthy, and at least 80 percent shall
have been planted for at least eight years.

                     (G)   Standards for the success of reforestation for commercial harvest shall
be established in consultation with forest management agencies and prior to approval of any mining
and reclamation plan that proposes reforestation.  If reforestation for commercial harvest is the
method of revegetation, reforestation shall be deemed to be complete when a reasonable population
density as established in the reclamation plan has been achieved, the trees have shown themselves
capable of continued growth for a minimum  period of five years following planting,  and the
understory vegetation is adequate to control erosion and is appropriate for the land use goal. Quality
and quantity, vegetation cover, productivity, and species diversity shall be determined in accordance
with scientifically acceptable sampling procedures approved by the Administrator.

                     (H)   If the Administrator approves a long-term, intensive  agricultural
postmining land use, the ten  year period of liability shall commence at the date of initial  planting

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                                    Development Document - Western Alkaline Coal Mining Sub category
for such long-term agricultural use.

                     (I)     When the  approved reclamation plan  is to return to cropland,
reclamation shall be deemed to be complete when productive capability is equivalent, for at least
two consecutive crop years, to the premining conditions or approved reference areas.  The premining
production data for the reclaimed site shall be considered in judging completeness  of reclamation
whenever said data are available.

              (xi)    Monitoring of permanent revegetation on reclaimed areas before and after
grazing shall be conducted at intervals throughout the period prior to bond release in accordance
with the plan required by Chapter 2, Section 2(b)(vii). Monitoring results shall be presented in the
annual report.

              (xii)   Any plans for irrigation must be explained.

              (xiii) The operator must protect young vegetative growth from being destroyed by
livestock by fencing or other approved techniques for a period of at least two years, or until the
vegetation is capable of renewing itself with properly managed grazing and without supplemental
irrigation or fertilization.  The Administrator, permittee and the landowner or land managing agency
shall determine when the revegetated area is ready for livestock grazing.

              (xiv)  In those areas where there were no or very few noxious weeds prior to being
affected by mining, the operator must control and minimize the introduction of noxious weeds into
the revegetated areas for a period of at least five years after the initial seeding.
       (e)    Diversion systems and drainage control.

              (i)     Diversion of streams.

                     (A)    All diversions shall be  designed to assure public safety, prevent
material damage outside the permit area, and minimize adverse impacts to the hydrologic balance.

                     (B)    All diversions and associated structures shall be designed, constructed,
maintained and used to  ensure  stability, prevent, to the extent possible using best technology
currently available, additional contribution of suspended solids to streamflow outside the permit
area, and comply with all applicable local, State and Federal rules.

                     (C)    Permanent diversions of intermittent and perennial streams shall be
designed and constructed so as to be erosionally and geomorphically compatible with the natural
drainage system.

                     (D)    The  design  and construction of all  diversions for perennial  or
intermittent streams shall be certified by a qualified registered professional engineer as meeting the

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Development Document - Western Alkaline Coal Mining Sub category
diversion standards of these regulations and the approved permit.

                     (E)    When permanent  diversions are  constructed or stream channels
restored after temporary diversions, the operator shall:

                           (I)    Restore, enhance where  practicable,  or  maintain  natural
riparian vegetation on the banks and flood plain of the stream;

                           (II)    Establish or restore the  stream  characteristics,  including
aquatic habitats to approximate premining stream channel characteristics; and

                           (III)   Establish and restore erosionally stable stream channels and
flood plains.

                     (F)    The operator shall renovate all permanent diversions in accordance
with the approved reclamation plan prior to abandonment of the permit area.
                     (G)   When no longer needed to achieve the purpose for which they were
authorized,  all temporary  diversions shall  be removed  and the affected  land  regraded and
revegetated, in accordance with this Chapter.  Before diversions are removed, downstream water
treatment facilities previously protected by the diversion shall be modified or removed, as necessary,
to prevent overtopping or failure of the facilities. This
requirement shall not relieve the operator from maintaining water treatment facilities as otherwise
required.

              (ii)    Control of discharge or drainage.

                     (A)   Discharge from  sedimentation  ponds,  permanent and temporary
impoundments, coal-processing waste dams and embankments, and diversions shall be controlled,
by energy dissipators, riprap channels, and other devices, where necessary, to reduce erosion, to
prevent deepening or enlargement of stream channels, and to minimize disturbance of the hydrologic
balance.  Discharge  structures  shall  be designed  according to  standard  engineering design
procedures.

                     (B)   Drainage from acid-forming and toxic-forming material into ground
and surface water shall be avoided by:

                           (I)    Identifying, burying, and treating where necessary, material
which, in the judgment of the Administrator may adversely affect water quality if not treated or
buried;

                           (II)   Preventing water from coming into contact with acid-forming
and toxic-forming material and other measures as required by the Administrator; and

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                                    Development Document - Western Alkaline Coal Mining Sub category
                            (III)   Complying with the requirements of subsection (c)(xiii) of this
Section and such other measures deemed necessary by the Administrator to protect surface water
and groundwater.

                     (C)    Surface water shall not be diverted or otherwise discharged  into
underground mine workings unless specifically authorized by the Administrator per the requirements
of Chapter 19, Section 2(a) of these regulations.

              (iii)    In addition to meeting the standards of this Section, all  diversions of
groundwater discharge flows shall meet the standards of Section 2(e).

              (iv)    Diversion systems - Unchannelized surface water and ephemeral streams.

                     (A)    Surface water shall be diverted around the operation for the following
purposes:

                            (I)     To control water pollution.

                            (II)    To control unnecessary erosion.

                            (Ill)   To protect the on-going operation.

                            (IV)   To protect the water rights of downstream users.

                     (B)    Temporary diversion of surface runoff or diversions used for erosion
control shall meet the following standards:

                            (I)     In soils or other unconsolidated material, the sides of diversion
ditches shall be no steeper than 1/^:1.

                            (II)    In rock, the sides of diversion ditches shall not overhang.

                            (Ill)   In soils or unconsolidated materials, the sides and, in ditches
carrying intermittent discharges, the bottom shall be seeded with approved grasses so as to take
advantage of the next growing season.

                            (IV)   Rock riprap, concrete, soil cement or other methods shall be
used where necessary to prevent unnecessary erosion.

                            (V)    Culverts or bridges shall be installed where necessary to allow
access by the surface owner for fire control and other purposes.

                            (VI)   Diversion ditches shall in a nonerosive manner pass the peak
runoff from a 2-year, 6-hour precipitation event, or a storm duration that produces the largest peak
flow, as specified by the Administrator.

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Development Document - Western Alkaline Coal Mining Sub category
                     (C)    In no case shall diversion ditches di scharge upon topsoil storage areas,
spoil or other unconsolidated material such as newly reclaimed areas.

                     (D)    Permanent diversion structures shall be designed to be erosionally
stable during the passage of the peak runoff from a 100-year, 6-hour precipitation event, or a storm
duration that produces the largest peak flow, as specified by the Administrator.

              (v)     Diversion of intermittent and perennial streams.

                     (A)    In  no case shall spoil, topsoil, or other unconsolidated material be
pushed into, or placed below the flood level of a perennial or intermittent stream except during the
approved construction of the diversion of said stream.

                     (B)    The Wyoming Game and Fish Department shall be consulted prior to
the approval of a diversion of a perennial or intermittent stream.

                     (C)    The banks of a diverted perennial or intermittent stream shall be
protected by vegetation by planting approved species to take advantage of the next growing season.

                     (D)    The banks and channel of a diverted perennial or intermittent stream
shall be protected where necessary by rock, riprap or similar measures to minimize erosion and
degradation of water quality.  Permanent  diversions shall be  designed and  constructed to be
erosionally stable.  The design of the permanent diversion shall also be consistent with the role of
the fluvial system.

                     (E)    Mining on the flood plain of a perennial or intermittent stream shall
not be permitted if it would cause the uncontrolled diversion of the stream during periods of high
water.

                     (F)     Waters flowing  through or by the mining operation shall meet the
standards  set by the U.S. Environmental Protection Agency and the Wyoming Water  Quality
Division in regard to the effect of the operation upon such waters.

                     (G)    If temporary, the channel and flood plain shall be designed  to pass,
in a nonerosive manner, the 10-year, 6-hour precipitation event, or the capacity of the unmodified
stream channel immediately above and below the diversion, whichever capacity is greater, or a
duration having a  greater peak flow, as  specified by the Administrator.   Cross-sections of the
existing stream above, below and within the  disturbed  area may be used to determine the flow
capacities, channel configuration and shape.

                     (H)    If permanent, the channel and flood plain shall be designed  to pass,
in a nonerosive manner, the 100-year, 6-hour precipitation event, or a duration having a greater peak
flow, as specified by the Administrator. Cross-sections of the existing stream above, below and
within the disturbed area may be used to determine the flow capacities, channel configuration and
shape.

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                                    Development Document - Western Alkaline Coal Mining Sub category
       (f)     Sedimentation ponds.

              (i)     All surface drainage from affected lands excluding sedimentation ponds,
diversion ditches, and road disturbances, shall pass through a sedimentation pond(s) before leaving
the permit area.  Sedimentation control devices shall be constructed prior to disturbance.  The
Administrator may grant exemptions to the use  of sedimentation ponds where, by the use of
alternative sediment control measures, the drainage will meet effluent limitation standards or will
not degrade receiving waters.

              (ii)    Where the sedimentation pond(s) results in the mixing of drainage from
affected  lands with the drainage from undisturbed areas, the permittee shall comply with the
applicable effluent limitation standards for all of the mixed drainage where it leaves the permit area.

              (iii)    Sedimentation ponds shall be designed and constructed to comply with the
applicable requirements of subsection (g)(iv-vii) of this Chapter. They shall be located as near as
possible to the affected lands and out of intermittent or perennial streams; unless approved by the
Administrator.
              (iv)    Sedimentation ponds shall be operated and maintained to comply with the
requirements of the Water Quality Division and the State Engineer's Office and satisfy the following
requirements:

                     (A)    Chemicals that will harm fish, wildlife, and related environmental
values shall not be used for flocculation or other water treatments or if used these ponds will be
protected.

                     (B)    Sedimentation ponds shall be designed and maintained to contain
adequate sediment storage as determined by acceptable empirical methods.

                     (C)    Sluicing of collected sediments shall be prevented for the design
precipitation event.

                     (D)    All areas disturbed by the construction of the sedimentation pond shall
be revegetated as soon as practicable to reduce erosion.

              (v)    The design, construction, and maintenance of a sedimentation pond or other
sediment control  measures in accordance with this subsection shall not relieve the operator from
compliance with applicable effluent limitation standards of the Water Quality Division.
              (vi)    Sediment ponds shall be maintained until removal is authorized by the
Division and the affected lands have been stabilized and initial vegetation established
in accordance with the approved reclamation plan and the requirements of this Chapter. In no case

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Development Document - Western Alkaline Coal Mining Sub category
shall sediment ponds treating reclaimed lands be removed sooner than two years after the last
augmented seeding.

             (vii)   Sediment control measures for affected lands. Appropriate sediment control
measures  shall be designed, constructed,  and maintained using  the best technology currently
available to prevent additional contributions of sediment to streamflow or to runoff outside the
affected land. Such measures may consist of limiting the extent of disturbed land and stabilizing,
diverting, treating or otherwise controlling runoff.

       (g)    Permanent and temporary water impoundments.

             (i)     Permanent water impoundments  are prohibited unless authorized by the
Administrator on the basis that:

                    (A)    The impoundment and its water quality and quantity will support or
constitute a postmining use equal to or greater than the highest previous use of the land.

                    (B)    Discharge of water, if any, from the impoundment shall not degrade
the quality of receiving waters.

                    (C)    The surface landowner, if different from the mineral  owner, has
consented to the impoundment.

             (ii)    Permanent water impoundments.  Permanent water impoundments shall be
constructed in accordance with the following requirements:

                    (A)    Dams must contain an overflow notch and spillway so as to prevent
failure by overfilling and washing. Overflow notches and spillways must be riprapped with rock or
concrete to prevent erosion.

                    (B)    The slopes around all water impoundments must be gentle enough so
as not to present a safety hazard to humans or livestock and so as to accommodate revegetation.
Variations from this procedure may be approved by the Administrator based on the  conditions
present at the individual locality.

                    (C)    Mineral seams and other sources of possible water contamination
within the impoundment area must be covered with overburden or stabilized in such a manner to
prevent contamination of the impounded water.

                    (D)    Bentonite or other mire-producing material within the impoundment
basin shall be removed or covered with materials which will prevent hazards to man or beast.

             (iii)    The phrase "maj or impoundment" shall mean any structure impounding water,
sediment or slurry:
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                                   Development Document - Western Alkaline Coal Mining Sub category
                     (A)    To an elevation of 20 feet or more above the upstream toe to the crest
of the emergency spillway; or

                     (B)    To an elevation of five feet above the upstream toe of the structure and
has a storage volume of 20 acre-feet or more; or

                     (C)    Which will be retained as part of the postmining land use, and:

                           (I)    Has an embankment height greater than 20 feet as measured
from the downstream toe of the embankment to the top of the embankment; or

                           (II)    Has an impounding capacity of 20 acre-feet or greater.

              (iv)    The design,  construction  and maintenance of permanent  and temporary
impoundments shall be approved by the State Engineer's Office. In addition, the following design
and construction requirements shall be applicable:

                     (A)    The  design of impoundments  shall be  certified by  a qualified
registered professional engineer as designed to meet the requirements of this part and the applicable
requirements of the  State Engineer,  using  current, prudent engineering practices.   For  major
impoundments, the certification also shall be filed with the State Engineer.

                     (B)    The vertical portion of any remaining highwall shall be located far
enough below the low water line along the full extent  of highwall to provide adequate safety and
access for the proposed water users.

                     (C)    Faces of embankments  and  surrounding areas shall be vegetated,
except that faces where water is impounded may be riprapped or otherwise stabilized in accordance
with accepted design practices, or where appropriate, Water Quality Division rules and regulations.

                     (D)    The embankment, foundation, and abutments for all impoundments
shall be designed and constructed to be stable.  For any major impoundment  or any impoundment
which  may present a danger to life, property or the environment, the Administrator shall require
sufficient foundation investigations and laboratory testing to demonstrate foundation stability, and
shall require a minimum static safety factor of 1.5 for the normal pool with steady seepage saturation
conditions, and a seismic safety  factor of at least 1.2.

                     (E)    All vegetative and organic materials shall be removed and foundations
excavated and prepared to resist failure.  Cutoff trenches shall be installed if necessary to ensure
stability.

                     (F)    All impoundments shall be inspected regularly during construction
and  immediately after construction by  a qualified registered professional engineer  or qualified
professional specialist under the direction of a qualified professional engineer. These individuals
shall be experienced in impoundment construction. Immediately following each inspection a report

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Development Document - Western Alkaline Coal Mining Sub category
shall be prepared and certified by the engineer describing the construction work observed and its
conformance with the approved designs. All inspection reports shall be retained at the mine site and
submitted in the annual report to the Administrator.

                    (G)    After completion of construction and until final bond release or
removal, all impoundments shall be inspected annually by a qualified registered professional
engineer, or by a qualified professional specialist under the direction of the qualified professional
engineer.  These individuals shall be experienced in impoundment construction.  Immediately
following each inspection a report shall be prepared and certified by the engineer describing:

                           (I)     Existing   and   required   monitoring   procedures   and
instrumentation;

                           (II)    Depth and elevation of any impounded water;

                           (III)   Existing storage capacity;

                           (IV)   Aspects of the dam that may affect its stability or present any
other hazardous condition; and

                           (V)    If the impoundment is being maintained in accordance with
the approved design and this Chapter. All annual inspection reports shall be retained at the mine site
and annually submitted to the Administrator.

                    (H)    In addition to the post-construction annual inspection requirements
contained in paragraph (G) immediately above, all impoundments must be inspected during each
of the intervening calendar quarters by a qualified individual designated by the operator.  These
inspections shall look for appearances of structural weakness and other hazardous conditions.

                    (I)    Those impoundments subject to 30  CFR § 77.216 shall also be
inspected in accordance with 30 CFR § 77.216-3.

                    (J)    If any examination  of inspection discloses that a potential hazard
exists, the operator shall promptly inform the Administrator of the finding and  of the emergency
procedures formulated for public protection and remedial action.  If adequate procedures cannot be
formulated or  implemented the Administrator  shall  be notified immediately. The Administrator
shall then notify the appropriate agencies that other emergency procedures are required to protect
the public.

                    (K)    Impoundments meeting the criteria of 30 CFR  §  77.216(a) shall
comply with the requirements of 30 CFR § 77.216.  The plan required to be submitted to the District
Manager of MSHA under 30 CFR § 77.216 shall also be submitted to the Administrator as part of
the permit application.

              (v)    The design  precipitation  event for  the  spillways for  temporary water

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                                    Development Document - Western Alkaline Coal Mining Sub category
impoundments shall be a 25-year, 6-hour precipitation event, or a storm duration having a greater
peak flow, as may be required by the Administrator.

              (vi)    The design precipitation event for the spillways for a permanent impoundment
shall be a 100-year, 6-hour precipitation event, or a storm duration having a larger peak flow, as may
be required by the Administrator.

              (vii)   Before abandoning an area or seeking bond release, the operator shall ensure
that all temporary structures are removed and reclaimed, and that all permanent structures are
renovated, if necessary to meet the requirements of this subsection and to conform to the approved
reclamation plan.

              (viii) Tailings impoundments.

                     (A)    Impoundments to contain mill tailings or slurry tailings shall be
constructed  in accordance with established engineering principles and shall be approved by the
Wyoming State Engineer's Office. A copy of the State Engineer's approval shall be attached to the
application.

                     (B)    Reclamation of tailings impoundments shall be accomplished by
removal and storage of all topsoil present within the tailings basin.  After termination of operations,
the topsoil shall be replaced and revegetated in accordance with these rules and regulations. If other
methods of reclamation and stabilization against wind and water erosion are found to be necessary
because of natural conditions, this must be stated and described subject to the Administrator's
approval.

       (h)    Protection of Groundwater  Recharge Capacity - The recharge  capacity of the
reclaimed lands shall be restored to a condition which:

              (i)     Supports the approved postmining land use;

              (ii)    Minimizes disturbances to the prevailing hydrologic balance in the permit
area and in adjacent areas; and

              (iii)    Provides a rate of recharge that approximates the premining recharge rate.

       (i)     Surface water and groundwater quality and quantity  shall be monitored until final
bond release to determine the extent of the disturbance to the hydrologic balance. Monitoring shall
be adequate to plan for modification of surface mining activities, if necessary, to minimize adverse
affects on the water of the State. The operator is responsible for properly installing, operating,
maintaining and  removing  all  necessary monitoring equipment.  In addition, the operator  is
responsible  for conducting  monitoring in accordance  with the approved monitoring plan, and
submitting all routine monitoring results to the Administrator at least annually. Routine monitoring
results  shall also be maintained on-site and available to the Director's  designated authorized
representative, and shall be reasonably current. Noncompliance results for NPDES discharges shall

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Development Document - Western Alkaline Coal Mining Sub category
be promptly reported by the operator to the Water Quality Division Administrator.  The operator
shall promptly report all other noncompliance results to the Land Quality Division Administrator
and shall, after consultation with the Administrator, implement appropriate and prompt mitigative
measures for those noncompliance situations determined to be mining caused.  The monitoring
system shall be based on the results of the probable hydrologic consequences assessment and shall
include:

              (i)     A groundwater monitoring program to determine:

                     (A)    Infiltration rates, subsurface flows, and storage characteristics of the
reclaimed land and adjacent areas;

                     (B)    The effects of reclamation on the recharge capacity of the reclaimed
lands; and

                     (C)    Suitability of groundwater for current and approved postmining land
uses.

              (ii)    A surface water monitoring program which includes monitoring of surface
water flow and quality from affected lands including those that have been graded and stabilized.
Results of the monitoring will be used to demonstrate that the  quality and quantity of runoff from
affected lands with or without treatment will minimize disturbance to the hydrologic balance. Water
quality monitoring results for discharges other than those authorized by Water Quality Division shall
be reported  whenever results  indicate noncompliance  with effluent limitation  standards  or
degradation of the quality of receiving water shall be reported immediately. Monitoring results shall
be available for inspection at the mine site.

       (j)     Roads and other  transportation facilities.

              (i)     General standards for all transportation  facilities.

                     (A)    Roads and railroads. Constructed or upgraded roads and railroad spurs
shall be included within the permit area from that point that they provide exclusive service and shall
be covered by a reclamation bond.

                     (B)    Roads shall not be constructed up a stream channel or so close that
the material shall spill into the channel, unless specifically approved by the Administrator.

                     (C)    Streams shall be crossed at or near right angles unless  contouring
down to the streambed will result in less potential stream bank erosion. Structure of ford entrances
and exits must be constructed to prevent water from flowing down the roadway.

                     (D)    Drainage control structures shall be used as necessary to control runoff
and to minimize erosion,  sedimentation and flooding. Drainage facilities shall be installed as road
construction progresses.

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                                    Development Document - Western Alkaline Coal Mining Sub category
                     (E)     Culverts shall be installed at prominent drainageways, or as required
by the Administrator.  Where necessary, culverts must be protected from erosion by adequate rock,
concrete or riprap. Culverts and drainage pipes shall be constructed to avoid plugging, collapsing,
or erosion at inlets and outlets.

                     (F)     Trees and vegetation may  be cleared only for the essential width
necessary to maintain slope stability and to serve traffic needs.

                     (G)     Access,  haul roads  and drainage structures shall be  routinely
maintained.

                     (H)     Exemptions concerning roads.

                            (I)    If approval is obtained from the surface landowner to leave a
road unreclaimed, an operator may request in writing to the Land Quality Division that a road be
permitted to remain unreclaimed.  The operator must furnish proof of the surface landowner's
approval.   Final decision of road reclamation  will  be made  by the Land  Quality Division
Administrator.

                            (II)    In the event that the surface 1 andowner, a city or town, another
agency of the State of Wyoming or an agency of the United States government has requested that
a road not be reclaimed, no bond shall be required of the applicant for the reclamation of the road
and reclamation of the road shall notbe required; provided, however, that the Administrator receives
a copy of the written request from the surface owner, city or town, or agency of the State or Federal
Government, for retention of the road.

              (ii)    General performance standards for haul roads, access roads or light-use roads:

                     (A)     Roads shall be located on ridges or on the most stable available slopes
to minimize erosion,  sedimentation and flooding.   All  exposed surfaces shall be stabilized in
accordance with current, prudent engineering practices.

                     (B)     Acid or toxic-forming substances shall not be used in road surfacing.

                     (C)     To the extent possible using the best technology currently available,
roads shall not cause damage to fish, wildlife, and related environmental values and shall not cause
additional contributions of suspended solids to streamflow or to runoff outside the affected land or
permit area. Any such contribution shall not be in excess of limitations of State or Federal law or
degrade the quality of receiving water.

                     (D)     The normal flow of water in streambeds and drainage channels shall
not be significantly altered. Damage to public or private property shall be prevented or controlled.

                     (E)     All embankments shall have, at a minimum, a static safety factor of
1.3.

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Development Document - Western Alkaline Coal Mining Sub category
                     (F)    The design  and construction  or  reconstruction shall incorporate
appropriate limits for grade, width, surface materials, surface drainage control, culvert placement,
culvert size, and such other design criteria required by the Administrator to ensure environmental
protection and safety appropriate for the planned duration and use.

                     (G)    All roads shall be maintained and/or repaired, if damaged, to meet the
performance standards of this subsection.

                     (H)    All roads shall be closed to vehicular travel when no longer needed
and reclaimed in accordance with this Chapter, unless the road is retained for use under an approved
postmining land use.

              (iii)    Performance standards for haul roads and access roads.

                     (A)    Design  and construction:    The  design and  construction  or
reconstruction of haul roads and access roads shall be certified by  a registered professional engineer
as meeting the requirements of this subsection; current, prudent engineering practices;  and any
design criteria required by the Administrator.

                     (B)    Stream fords are prohibited unless they are specifically approved by
the Administrator as temporary routes during periods of construction.

                     (C)    Drainage.

                            (I)    Haul and  access  roads  shall  be designed, constructed, or
reconstructed and maintained with drainage control structures capable of safely passing the runoff
from a 10-year, 6-hour precipitation event, or a storm duration having a greater peak flow, unless
otherwise specifically approved by the Administrator. The drainage control  system shall include,
but not be limited to bridges, culverts, ditches, cross drains, and  ditch-relief drains.

                            (II)   All  drainage pipes or  culverts  shall   be  constructed  and
maintained to avoid plugging, collapse and erosion at inlets and  outlets.

                            (Ill)   All culverts shall be designed, constructed, and maintained to
sustain the vertical soil pressure, passive resistance of the foundation, and the weight of vehicles to
be used.

                            (IV)   Ephemeral (shown  on a USGS 7.5 minute series quad),
intermittent or perennial streams shall not be altered  or  relocated for road  construction or
reconstruction without approval from the Administrator, and then, only if the natural channel
drainage is not blocked  except during periods of low flow or when flow  has been acceptably
diverted  around the  site, there  is no significant damage to hydrologic balance, and there is no
adverse impact on adjoining landowners.

                            (V)   Drainage ditches shall be designed to  prevent uncontrolled

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                                    Development Document - Western Alkaline Coal Mining Sub category
drainage over the road surface and embankment.  Trash racks and debris basins shall be installed
in the drainage ditches where debris from the drainage area may impair the functions of drainage
and sediment control structures.

                            (VI)   Except as provided in (B) above, drainage structures which are
used for stream channel crossings shall be made using bridges, culverts, or other structures designed,
constructed, and maintained using current, prudent engineering practices.

                     (D)    Surfacing: Roads shall be surfaced with rock, crushed gravel, asphalt,
or other material sufficiently durable for the anticipated volume  of traffic and weight and speed of
vehicles to be used.

                     (E)    Maintenance: Routine maintenance shall include repairs to the road
surface, blading, filling potholes and adding replacement gravel or asphalt.  It shall also include
revegetation, brush removal, and minor reconstruction of road segments as necessary.

              (iv)    Railroad and other transportation and mine facilities.

                     (A)    Railroad loops, spurs, sidings, surface conveyor systems, chutes, aerial
tramways, or other transportation and mine facilities shall be designed, constructed, or reconstructed,
and maintained and the area restored to:

                            (I)     Prevent, to the extent possible using the best technology
currently  available, damage to fish, wildlife,  and related environmental values, and  additional
contributions of suspended solids to streamflow or runoff outside the affected land and permit area.
Any such contributions shall not be in excess of limitations of State or Federal law or degrade the
quality of receiving water.

                            (II)    Control  and minimize diminution or degradation of water
quality and quantity.

                            (Ill)   Control and minimize erosion and siltation.

                            (IV)   Control and minimize air pollution.

                            (V)    Prevent damage to public or private property.

                     (B)    Railroads  and other transportation and mine facility areas shall be
reclaimed when no longer needed for the operation in accordance with the requirements of this
Chapter.

       (k)    Time schedule.

              (i)     Reclamation  must begin as soon as possible after mining commences and
must continue concurrently  until such time that the mining operation is terminated and all of the

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Development Document - Western Alkaline Coal Mining Sub category
affected land is reclaimed.  If conditions are such that final reclamation procedures cannot begin
until the mining operation is completed, this must be explained in the reclamation plan. A detailed
time schedule for the mining and reclamation progression must be included in the reclamation plan.
This time schedule shall:

                     (A)    Apply to reclamation of all lands to be affected in the permit area;

                     (B)    Designate times for backfilling, grading, contouring and reseeding;

                     (C)    Be coordinated with a map indicating the areas of progressive mining
and reclamation;

                     (D)    Establish reclamation concurrently with mining operations, whenever
possible. If not possible, the schedule shall provide for the earliest possible reclamation consistent
with the orderly and economic development of the  property; and

                     (E)    If the Administrator approves a schedule where reclamation follows
the completion of mining, describe the conditions which will constitute completion or termination
of mineral production.

       (1)     Unanticipated conditions.

              (i)     An  operator encountering   unanticipated  conditions  shall  notify  the
Administrator as soon as possible and in no event more than five days after making the discovery.

              (ii)     An unanticipated  condition is  any  condition encountered in a mining
operation and not mentioned by the operator in his mining or reclamation plan which may seriously
affect the procedures, timing, or outcome of mining or reclamation.  Such unanticipated conditions
include but are not limited to the following:

                     (A)    The uncovering during  mining operations of any acid-forming,
radioactive, inflammable,  or  toxic materials which must be burned, impounded, or otherwise
disposed of in order to eliminate pollution or safety hazards.

                     (B)    The discovery  during  mining operations of a significant flow of
groundwater in any stratigraphic horizon.

                     (C)    The occurrence of slides, faults,  or  unstable soil and overburden
materials which may cause sliding or caving in a pit which could cause problems or delays with
mining or reclamation.

                     (D)    The occurrence of uncontrolled underground caving or subsidence
which reaches the surface, causing problems with reclamation and safety hazards.

                     (E)    A  discovery of  significant  archaeological  or paleontological

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                                    Development Document - Western Alkaline Coal Mining Sub category
importance.

              (iii)    In the case of the uncovering of hazardous materials, the operator shall take
immediate steps to notify the Administrator and comply with any required measures to eliminate the
pollution or safety hazard.  Under all conditions the operator must take appropriate measures to
correct, eliminate, or adapt to an unanticipated condition before mining resumes in the immediate
vicinity of that condition.

       (m)    Disposal of buildings and structures.

              (i)     All buildings and structures constructed, used or improved by the operator
must be removed or dismantled unless it can be demonstrated to the Administrator's satisfaction that
the buildings or structures will be of beneficial use in accomplishing the proposed use of the land
after reclamation  or for environmental monitoring.

              (ii)    If the operator does not wish to remove certain buildings or facilities, he must
obtain the written consent of the surface landowner to leave the buildings or facilities intact. The
operator must make a request in writing, providing written proof of the above to the Land Quality
Division, that the buildings or facilities be permitted to remain intact.

       (n)    All support buildings,  including loading and storage facilities, plants, sheds,  shops
and other buildings shall be designed, constructed or reconstructed and located to prevent or control
erosion, pollution, and damage to public or private property, fish, wildlife, and related environmental
values. All operations shall be conducted so as to minimize disruption of any services provided by
facilities located on,  under or through the permit area, unless otherwise approved by  the
Administrator or owner of such facilities.

       (o)    Signs and markers. Uniform and durable signs and markers of an adequate size shall
be posted by the operator at those points applicable to the areas or activities to which they pertain.
Such signs and markers shall include mine and permit identification signs, perimeter markers, buffer
zone markers, blasting signs and soil markers. The operator shall place and maintain all signs and
markers prior to commencement and until the completion of the activities to which they pertain,
which, for mine and permit identification signs,  shall be at the time the bond is released.

       (p)    Drilled holes and other exposed underground openings:  Plugging, sealing and
capping of all drilled holes except those used solely for blasting or developmental drill holes which
will be mined through within one year shall meet the requirements of Chapter 14. Developmental
drilling shall meet the plugging and sealing requirements  of W.S.  § 35-11-404, where necessary.
Temporary sealing and use of protective devices may be approved by the Administrator if the hole
will be used for returning coal-processing waste or water to underground workings or monitoring
groundwater conditions, and shall be used, at a minimum, for developmental drilling. Other exposed
underground openings shall be properly managed as required by the Administrator to prevent access
to mine workings and to keep acid or other toxic drainage from entering ground or surface water.

              (i)     With the prior approval of the Administrator and the State Engineer, wells

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Development Document - Western Alkaline Coal Mining Sub category
may be transferred to another party for further use.  The permittee shall remain responsible for the
proper management of the well until final bond release.

       (q)    Air resources protection. All exposed surface areas shall be protected and stabilized
to effectively control erosion  and air pollution attendant to erosion.

       (r)     Fish and wildlife performance standards.

              (i)     An operator shall, to the extent possible using the best technology currently
available   and  consistent  with   the   approved   postmining   land   use,  minimize
disturbance and adverse impacts on fish, wildlife, and related environmental values, and achieve
enhancement of such resources where practicable, which activities shall include:

                     (A)    Properly construct, locate and operate roads and power lines, including
proper design of power lines to avoid electrocution of raptors.

                     (B)    Prevent access to areas such as roadways or ponds with hazardous
materials, to avoid damage to wildlife without limiting access to known important routes.

                     (C)    Afford protection, restore and enhance where practicable important
habitats to fish and wildlife.  This shall include, but is not limited to, wetlands and  riparian
vegetation along rivers and streams and bordering ponds and lakes.

                     (D)    Select plant species with shrubs well represented, which will enhance
the nutritional and cover aspects offish and wildlife habitat, where such habitat is identified as part
of the postmining use, and distribute the reestablished habitat in a manner which includes a diversity
and interspersion of habitats,  optimizes edge effect, cover and other benefits for fish and wildlife,
and is consistent with Section 2(d)(x)(E).

                     (E)     Promptly report to the regulatory authority any species or critical
habitat of such species listed  as threatened or endangered, or any golden or bald eagle nest in or
adjacent to the permit area, which was not reported or investigated in the permit application.  Upon
notification the Administrator shall consult with the Wyoming Game and  Fish Department and the
U.S. Fish and Wildlife  Service  and, after  consultation, shall identify whether and under what
conditions the operator may proceed.

                     (F)     Where  the postmining land use is for  cropland, to the extent not
inconsistent with this intended use, operators shall restore habitat types to break up large blocks of
monocultures.

              (ii)    Stream buffer zone.

                     (A)    No land within 100 feet of a perennial or intermittent stream shall be
affected unless the Administrator specifically authorizes such activities closer to or through such a
stream upon a finding that:

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                                    Development Document - Western Alkaline Coal Mining Sub category
                            (I)     Surface mining activities will not cause or contribute to the
violation of applicable state or federal water quality standards, and will not adversely affect the
water quantity and quality or other environmental resources of the stream; and

                            (II)    If there will be a temporary or permanent  stream-channel
diversion, it will comply with all stream diversion requirements.

                     (B)    The area not to be affected shall be designated a buffer zone, marked
in the field and on the mine plan map.

              (iii)    No surface mining activity shall be conducted which is likely to jeopardize
the continued existence of endangered or threatened species listed by the State or the Secretary of
the Interior or which will result in the destruction or adverse modification of designated critical
habitats of such species in violation of the Endangered Species Act (16 U.S.C. 1531  et seq.). No
surface mining activity shall be conducted in a manner which would result in the unlawful taking
of a bald or golden eagle, its nest, or any of its eggs. The Administrator shall consult with the State
and Federal Fish and Wildlife Agencies to identify whether and under what conditions the operation
may continue under this provision.

              (iv)    The operator shall perform periodic surveys, in the level of detail and for
those areas as determined by the Administrator, in accordance with Appendix B of these rules and
regulations.

       (s)     Slides  and other damage.  Where instability may exist in backfill materials,  an
undisturbed natural barrier shall be provided to prevent slides and erosion, beginning at the elevation
of the lowest coal seam to be mined and extending from the outslope for such distance as may be
determined by the Administrator.

       (t)     Only those operations designed to protect disturbed surface areas and which result
in improved resource recovery, abatement of water pollution, or elimination of hazards to the public
shall be conducted within 500 feet of an active or abandoned underground mine. Approval for such
operation shall be obtained from MSHA for operations proposed  to be conducted within 500 feet
of an active underground mine. The Administrator shall specifically approve operations proposed
to be conducted within 500 feet of an abandoned underground mine.

       (u)     Cessation of operations. When it is known that a temporary cessation of operations
will extend beyond 3 0 days, the operator shall submit to the Administrator that information required
in an annual report.

       (v)     The  operator shall conduct operations so  as to maximize  the  utilization and
conservation of the solid fuel resource being recovered  so that reaffecting the land in the future can
be minimized.

       (w)    The operator shall conduct all operations in such a manner as to minimize disturbance
of the hydrologic balance within the permit and adjacent areas, to prevent material damage to the

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Development Document - Western Alkaline Coal Mining Sub category
hydrologic balance outside the permit area, to assure the protection or replacement of water rights,
and to support approved postmining land uses in accordance with the terms and conditions of the
approved permit and the performance standards of this Chapter. Mining and reclamation practices
that minimize water pollution and changes in flow shall be used in preference to water treatment.
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                                Development Document - Western Alkaline Coal Mining Subcategory
Appendix B:   Wyoming Guideline No. 15
                    (HP/2-90, Riles Update/8-94)
Appendix B

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Development Document - Western Alkaline Coal Mining Sub category
                                                                                        Appendix B

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                                      Development Document - Western Alkaline Coal Mining Sub category
                WYOMING DEPARTMENT OF ENVIRONMENTAL QUALITY
                                 LAND QUALITY DIVISION
                                     GUIDELINE NO. 15

                     ALTERNATIVE SEDIMENT CONTROL MEASURES
       This document is a guideline only. Its contents are not to be interpreted by applicants, operators,
or LQD staff as mandatory. If an operator wishes to pursue other alternatives, he or she is encouraged to
discuss these alternatives with the LQD staff.

I.      INTRODUCTION

       This guideline identifies specific sediment control measures that may be used in addition to or in
place of sedimentation ponds. Operators should note that alternative sediment control design
requirements are minimal for areas less than 30 acres.  Monitoring requirements are also minimal for
small ephemeral receiving streams (drainage areas less than 0.5 square miles). Land Quality Division
(LQD) will rely on field inspections  of small areas, focusing on construction and maintenance to ensure
their effectiveness.

       These recommendations do not constitute the only acceptable alternative sediment control
techniques. LQD  intends to maintain flexibility so that they can evaluate sediment control systems not
envisioned in this  guideline. The final sediment control system should conform to the standards
described herein for design, construction, maintenance, and monitoring.

       Even where sedimentation ponds are constructed, alternative sediment control changes can be
used to minimize sediment delivery to ponds and thereby decrease the frequency of pond maintenance.
Alternative techniques are especially applicable to large reclaimed watersheds, where erosion must be
controlled before a downstream pond is eliminated.

II.     Objective of Alternative Sediment Control Measures (ASCM's)

       Alternative sediment control measures are presented as an option other than the use of
sedimentation ponds in the WDEQ/LQD Coal Rules and Regulations when it can be demonstrated that
they "will not degrade receiving waters" (Chapter IV, Section 2.(f)(I)). Receiving waters are defined by
the LQD  as:

       1.     Any unimpounded and undisturbed or permanently reclaimed stream outside of the
              permit area that is within three (3) channel miles downstream of an area controlled by an
              ASCM; or

       2.     Any unimpounded and undisturbed or permanently reclaimed stream within the permit
              area downstream of an ASCM.

       As stated in Chapter IV, Section 2.(f)(vii), "Appropriate sediment control measures shall be
designed, constructed, and maintained using the best technology currently available to prevent additional
contributions of sediment to streamflow or to runoff outside the affected land". Also, a surface water
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Development Document - Western Alkaline Coal Mining Sub category
monitoring program "...will be used to demonstrate that the quality and quantity of runoff from affected
lands...will minimize disturbance to the hydrologic balance". (Chapter IV, Section 2.(I)(ii)).

       These regulations suggest that there is a design/maintenance standard, best technology currently
available (BTCA), a performance standard, non-degradation of receiving waters, and a verification
standard, demonstrable monitoring program. ASCM's should be designed such that it can be
demonstrated that sediment yields are not greater than background levels.

III.    Best Technology Currently Available (BTCA)

       A.      Elements of BTCA.

               The design methods, construction techniques, maintenance practices and monitoring
               system all contribute to a system that can be considered BTCA.

       B.      Determination of BTCA.

               1.      BTCA will be determined on a case by case basis.  BTCA determinations will be
                      based on the type of disturbance, the size of the disturbance and the length of
                      time the ASCM will be in place. The LQD will not require the same ASCM
                      sophistication on, for example, small temporary topsoil stockpiles or topsoil
                      stripping areas as they will for a permanently reclaimed watershed.  The
                      determination of BTCA will be based on how effective the ASCM is at:

                      a.      Preventing soil detachment and erosion, using slope erosion control
                             practices.

                      b.     Retaining sediment as close as possible to its point of origin, using on-
                             slope and in-channel sediment trapping structures.

                      It is preferable to use effective slope erosion control practices where possible.
                      Sediment traps should constitute a second line of defense.

               2.      The LQD realizes that many technologies currently exist that can be considered
                      the "best" technology. New technologies may be developed in the near future
                      that may provide a higher degree of erosion protection than is "currently"
                      available.
IV.    Design of ASCM's

       ASCM's can be considered for disturbed or reclaimed areas that are not within one-half mile
(channel distance) of any class I, II, or III stream. (These classes are defined in the WDEQ/WQD Rules
and Regulations, Chapter I, Section 4). Small areas (less than 30 acres) located within one half mile of a
class I, II, or III stream, may be protected using ASCM's, subject to the discretion of the LQD
administrator.

       A.      Designing ASCM's for Small Areas (less than 30 acres)
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                                       Development Document - Western Alkaline Coal Mining Sub category
               The only sediment control design requirements for small disturbed area (less than 30
               acres) are:

               1.       Sediment trapping structures (e.g., toe ditches, rock check dams) should be
                       designed to pass or detain runoff from storms of recurrence intervals determined
                       by their expected lifetimes (see Appendix 1).  A generic design may be
                       acceptable where many similar small areas will be controlled by similar
                       structures as long as they will withstand the design precipitation event.

               2.       Rocks used to construct check dams should be angular and have an appropriate
                       size distribution so that the design peak flow cannot entrain them or else be
                       enclosed in a staked wire mesh structure.

               3.       Toe ditches should be graded to a zero slope, where practical. Otherwise, toe
                       ditches should be gently graded to a stabilized outlet that has a check dam  of
                       porous rock, staked hay bales,  or a fabric sediment fence to retain sediment.

               4.       Detention basins will be considered alternative sediment control only when their
                       capacity is less than 0.5 acre-foot.

               5.       The operator need only report the ASCM design and its justification with a
                       planview location and a general description of the type structure to the LQD.
                       Proposals of this size should outline the inspection and maintenance programs
                       the operator will use to regularly evaluate the stability and effectiveness of each
                       ASCM.

        B.     Designing ASCM's for Large Areas  (30 acres and larger)

               1.       The design of ASCM's for large areas should be based on predicted sediment
                       loads or yields from the particular area of disturbance. The operator should
                       compare predicted or measured native sediment yields to those predicted for the
                       disturbed area.

               2.       A state-of-the-art computer watershed model should be used as an ASCM design
                       tool. The LQD will work with the operator to determine which model(s) can be
                       considered state-of-the-art for the particular application.  Section VII of this
                       guideline includes specific model information that should be  submitted.

        C.     Implementation Priorities for Various ASCM's

               The following lists prioritize the most desirable ASCM's for each particular disturbed
               area:

               1.       Topsoil Stripping Areas

                       a.      Divert undisturbed water around the stripped area into an approved
                              diversion channel.
                       b.      Divert drainage from the stripped area into the pit.
                       c.      Divert drainage from the stripped area away from the pit through an
                              ASCM:

Appendix B                                                                                   B-3

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Development Document - Western Alkaline Coal Mining Sub category
                              1.      Place native vegetation buffer strips or filter cloth between the
                                     disturbance and the channel.
                              2.      Place sediment trapping structures in channel (porous rock check
                                     dams, staked straw bales).
                              3.      Place sediment trapping structures below the channel grade.

               2.      Overburden/Topsoil Stockpiles

                      a.      Utilize a flat construction profile.
                      b.      Locate stockpiles away from drainageways.
                      c.      Use contour plowing, seeding and mulch on stockpiles.
                      d.      Establish a good vegetative cover.
                      e.      Grade contour ditch outlets to stabilized drainageways.
                      f.      Grade toe ditches to sediment trapping structure that retains minimum
                              amount of water.
                      g.      Grade toe ditches to zero grade and less than 0.5 acre-foot capacity.

               3.      Postmining Surfaces

                      a.      Stable landform design

                              Geomorphic approaches to stable landform design are highly
                              recommended to minimize sediment yield. For example, drainage
                              density and channel and hillslope profile shapes can be varied and lose
                              lengths reduced to minimize sediment yield.

                      b.      Short-term slope erosion controls

                              1.      Regraded topsoil surfaces should be pitted with a large disc,
                                     chisel plow or ripper working along the contour to increase
                                     infiltration and detain runoff.

                              2.      Bare rounded surfaces should be mulched and vegetated rapidly.
                                     It is highly recommended that mulch be anchored in the topsoil
                                     and that vegetation be planted immediately after surface  grading.
                                     Cover crops provide a standing mulch that can be mowed prior
                                     to subsequent plantings.

                      c.      In-channel sediment retention measures

                              Vegetation is often sufficient to stabilize stream channels. A rock check
                              dam should be placed in channel reaches that produce excessive
                              sediment from their bed and banks. Accumulated sediment should be
                              regularly removed from rock check dams.  Check dams should be used as
                              a final resort in permanently reclaimed stream channels.
       D.      Location of Sedimentation Ponds

               Sedimentation ponds must be used to control runoff from facilities areas, coal stockpiles

B-4                                                                                   Appendix B

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                                      Development Document - Western Alkaline Coal Mining Sub category
               and pit drainage.  Sediment ponds may also be necessary when maintenance of ASCM's
               is a chronic unresolved problem.
V.      Construction and Maintenance of ASCM's

        A.      Construction of ASCM's

               Each type of ASCM has construction and maintenance guidelines that are specified in
               most handbooks on sediment control (see list of references, Appendix 2). Some basic
               guidelines include:

               1.      Mulch must be anchored to prevent it from being washed or blown off the slope.

               2.      Rocks used in porous rock check dams should be the appropriate size, angularity,
                      and density to prevent flows from transporting them or else they should be
                      contained in anchored wire mesh.

               3.      Contour ditches should be constructed with a stabilized outlet and berms that are
                      well compacted and vegetated.

               4.      Concentrating flow in a diversion ditch can result in severe erosion by gullying if
                      the outlet is not adequately constructed and stabilized.

               5.      Baled hay check dams should be staked into the bed and banks of channels.
                      Flow should pass over the low point of the channel. If hay bales are placed level
                      across the channel, they should be staggered so that water will not pond behind
                      them and be deflected into the banks.

        B.      Maintenance of ASCM's

               The operator should report, repair and log any significant damage to an ASCM as soon as
               possible after the damage occurs.  The operator should inspect the ASCM at the
               beginning and at  the end of each runoff season, and after each runoff event. An
               inspection and maintenance log  should be kept to document the condition of each ASCM
               at the time of each inspection. The log should describe any damage, the required
               maintenance, and the date repairs were made.
VI.     Performance of ASCM's

        A.      Monitoring Ephemeral Tributary (Class IV) Streams

               Where the receiving water is an ephemeral (Class IV) stream, the water quality standard
               set by WDEQ/WQD Rules and Regulations, Chapter 1, Section 15, is as follows:

               "...substances...influenced by the activities of man that will settle to form sludge, bank or
               bottom deposits shall not be present in quantities which could result in significant
               aesthetic degradation, ... or adversely affect public water supplies, agricultural or
               industrial water use, plant life or wildlife, etc."

Appendix B                                                                                   B-5

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Development Document - Western Alkaline Coal Mining Sub category
               1.      Small ephemeral receiving streams

                      Small ephemeral receiving streams (drainage areas less than 0.5 square miles)
                      that are receiving waters for ASCM's should be visually inspected after each
                      runoff event.

                      a.      Channels and hillslopes should be inspected for signs of rill and gully
                             erosion.  The volume and location of any recently accumulated
                             sediments should be recorded.

                      b.      Repeat photographs should be taken at least annually and after large
                             runoff events at several permanent locations along the receiving stream
                             to supplement the written record of observations.

               2.      Large ephemeral receiving streams

                      In addition to the requirements for visually monitoring small ephemeral receiving
                      streams, monitoring of large ephemeral receiving streams (drainage areas greater
                      than 0.5 square mile) should include one, or both, of the following:

                      a.      Repeat surveys of representative permanently benchmarked stream
                             channel cross sections located within the disturbed reach of the channel
                             and  continuing into the receiving stream channel.

                      b.      Upstream and downstream sediment yield monitoring stations that follow
                             the plan  set forth for Class I, II, and III streams below.

       B.      Monitoring Class I, II, and III streams

               Any class I, II or III  receiving stream should be monitored upstream and downstream of
               the disturbed area so that any potential increase in sediment load related to mining
               disturbance can be detected.

               1.      The methods of data collection and the analytical basis for determining whether
                      or not degradation has occurred should be outlined in detail in the ASCM
                      proposal.

               2.      Continuous flow recorders and automatic sediment samplers should be installed
                      at permanent upstream and downstream  station locations.

               3.      Automatic sediment samplers should begin sampling at the onset of each runoff
                      event and continue at 5 to 10 minute intervals throughout each runoff event.
                      Other sampling intervals or methods will be considered according to their ability
                      to verify sediment yields.

               4.      The applicant should submit a monitoring station maintenance plan. Data from
                      monitoring stations should be retrieved within 24 hours of each runoff event.
                      Faulty equipment should be immediately repaired or replaced. Monitoring
                      stations should be inspected by the operator after every runoff event, and  a log of

B-6                                                                                   Appendix B

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                                       Development Document - Western Alkaline Coal Mining Sub category
                      monitoring and maintenance activities should be kept for LQD review. The LQD
                      will be looking for a long-term record of maintenance as well as a company's
                      efforts to correct problems in a timely fashion.
VII.    Contents of an ASCM Proposal

        The proposal for implementation of an ASCM for areas greater than 30 acres should include the
        following items:

        A.     A general description of the area to be controlled by ASCM's and the types and duration
               of expected disturbance include the distance to and type of nearest receiving stream
               and/or Class I, II, or III stream.

        B.     Description of the ASCM Design Procedure

               1.      List and justify values chosen for the watershed (or subwatershed) variables and
                      model parameters (e.g., soils, sediment grain size distribution, slopes, etc.).

               2.      Where applicable, submit data used to calibrate model and the calibration results
                      (e.g., design hydrographs, hyetographs, curve numbers, etc.).

               3.      Explain the choice of ASCM's.

               4.      Submit and justify the design storm recurrence interval and duration, runoff
                      volume, and peak discharge.

               5.      Submit sample calculations and/or computer model output.

        C.     Provide a map of ASCM's on a mining sequence topographic map or overlay. Each
               ASCM should be referenced in the descriptive text and design information, and dates of
               construction or implementation of each ASCM should be given.  This map should be
               updated in each Annual Report if modifications are made.

        D.     Provide specifications for each ASCM and a schematic diagram of each typical structure.

        E.     For reclaimed areas:

               1.      Refer to drainage basin and channel designs in reclamation plan:

                      a.     Longitudinal profiles of reclaimed channels.

                      b.     Typical reclaimed channel cross sections.

                      c.     Reclaimed area contour map with 10' or less contour interval.

                      d.     Justification of drainage basin design.

                      e.     Reclaimed basin characteristics such as: relief ratio, drainage area,
                             topsoil and spoil particle sizes, average channel slope. Include
                             discussion of how reclaimed basins, slopes and channels are  designed to
                             minimize additional  sediment yield to downstream areas.

Appendix B                                                                                   B-7

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Development Document - Western Alkaline Coal Mining Sub category
               2.       Surface treatments (mulch, contour ripping).

               3.       Channel protection measures, if any.

        F.      Maintenance and inspection plan.

        G.      Monitoring plan and description of degradation analysis.

        H.      If any impounding structure is designed to retain more than 2.0 ac-ft of water, a WQD
               permit must be obtained.

        I.      ASCM's designed to control large disturbed watersheds  (excluding isolated small areas)
               may need to be permitted through the State Engineer's Office (Form SW-1, Application
               to Appropriate Surface Water). The State Engineer's Office should be contacted directly
               to determine whether or not such a permit is required.
B-8                                                                                    Appendix B

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                                       Development Document - Western Alkaline Coal Mining Sub category
                                         APPENDIX 1

                              Design Events for Temporary Structures
Exceedance of the design runoff is likely to result in destruction of in-channel ASCM's and in the
remobilization of any stored sediment. Therefore, temporary structures should be designed for an event
with some reasonably small probability of occurrence over the structure's lifetime.
Example:
        The highest acceptable risk of structure failure during that structure's lifetime is 20%.

               Table 1 shows event return periods for which the risk of failure (at least once) over a
               given number of years will be no greater than 20%. The return periods in Table 1 were
               calculated from the following equation:
               where P is the probability that an event of return period t will be equaled or exceeded at
               least once during the course of n years (Linsley, Kohler and Paulhus, 1982).
Table 1 - Design Event Return Periods
Expected Lifetime of Structure (yrs)
Design Event Return Period (yrs)
2
10
5
25
7
33
10
50
               Over any two-year period, a 10-year event has a 20% chance of being equaled or exceeded
               at least once.  Therefore, based on the criterion of 20% acceptable risk of failure, the
               appropriate design storm for a structure intended to function for two years is the 10-year
               peak runoff, or predicted peak runoff from the 10-year rainfall.  For structure lifetimes
               outside the range of those in Table 1,  appropriate design storm return periods should be
               calculated in the same manner from the equation given above.
Appendix B
B-9

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Development Document - Western Alkaline Coal Mining Sub category
                                        APPENDIX 2

                                          References

Barfield, B.J., R.C. Warner and C.T. Haan (1985). Applied Hydrology and Sedimentology For Disturbed
       Areas. Oklahoma Technical Press, Stillwater, Oklahoma, 603 pp.

Dollhopf, D.J. et al (1985). Effects of Surface Manipulation on Mined Land Reclamation. Montana Ag.
       Expt. Sta.  Spec. Rpt 18

Erosion and Sediment Control:  Surface Mining in the Eastern U.S. EPA Technology Transfer Seminar
       Public, EPA-625/3-76-006. USDA Soil Conservation Service. Nation Engineering Handbook.

Gray, D.H. & Leiser A.T. (1982). Biotechnical Slope Protection & Erosion Control. VanNostrand Reinhold
       Co., NY

Gregory, D.I., S.A. Schumm, & C.C. Watson (1985). Determination of Drainage Density for Surface Mine
       Reclamation in the Western U.S. Water Eng. Tech, Ive., Rpt. prepared for OSM, Denver

Grim, E.G.  & Hill, R.D. (1974) Environmental Protection - Surface Mining of Coal.  EPA-670/2-74-093
       (EOA, Cincinnati)

Guidelines  for Erosion and Sediment Control Planning  and Implementation (1972).  EPA Protection
       Technology Services, EPA-R2-72-015, EPA Office of Research & Monitoring, Washington, D.C.

Hittman, Assoc. & Natural Resources Consultants (1981).  Erosion & Sediment Control Measures for Coal
       Mines.  H-C1022/001-81-1008P. Report prepared for OSM, Washington, D.C.

Linsley, R  K., M. A. Kohler, and J. L. H. Paulhus (1982). Hydrology for Engineers, McGraw-Hill Book
       Co., New York, New York.

Mining &  Reclamation Council of America (1985).   Handbook of Alternative  Sediment Control
       Methodologies for Mined Lands.  Report prepared for OSM, Washington, D.C. under contract
       H5130424 by Hess & Fish Engineers.

Morris, R.N., Basi, F.E. & Doehring, D.O. (1980). A Literature Review: Mined-Land Sediment Control and
       the  Dryland Fluvial System. Report Prepared for Pittsburg & Midway Coal Mining Company by
       Research Institute of Colorado.

Simons, Li & Assoc. (1982). Engineering Analysis of Fluvial Systems.  SLA, Ft. Collins, Co.

Simons, Li  & Assoc.  (1983).  Design of Sediment Control Measures for Small Areas in  Surface Mining.
       Report Prepared for OSM.

USDA-SCS Engineering Field Manual for Conservation Practices S. Doc: A57.6/2: En 3/3/984
B-10                                                                               Appendix B

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                               Development Document - Western Alkaline Coal Mining Subcategory
Appendix C:    19 NMAC 8.2, Subpart 20, Section 2009
Appendix C

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Development Document - Western Alkaline Coal Mining Sub category
                                                                                        Appendix C

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                                     Development Document - Western Alkaline Coal Mining Sub category
Introduction

       New Mexico's Mining and Minerals Division (MMD) enforces the state's federally

approved SMCRA primacy program.  BMP regulations for coal mining and reclamation

operations in New Mexico may be found under 19 NMAC 8.2 Subpart 20 Section 2009 which

addresses general requirements for minimizing changes to the prevailing hydrologic balance in

both the permit and adjacent areas.  Section 2009 of Subpart 20 is presented below:



19 NMAC 8.2.20.2009 HYDROLOGIC BALANCE: GENERAL REQUIREMENTS

2009.A Surface coal mining operations shall be planned and conducted to minimize changes to the
prevailing hydrologic balance in both the permit and adjacent areas and prevent material damage outside
of the permit area in order to prevent adverse changes in that balance that could result from those
operations. [11-29-97]

2009.B Changes in water quality and quantity, in depth to ground water, and in the location of surface
water drainage channels shall be minimized so that the approved postmining land use of the permit area is
not adversely affected. [11-29-97]

2009.C In no case shall Federal and  State water quality statutes, regulations, standards, or effluent
limitations be violated. [11-29-97]

2009.D Operations shall be conducted to minimize water pollution and, where necessary, sediment ponds
or other treatment facilities shall be used to control water pollution.

       (1)     Each person who conducts surface coal mining operations shall emphasize mining and
               reclamation practices that prevent or minimize water pollution. Methods listed in
               paragraph 2009.D(2) and (3) shall be capable of containing or treating all surface flow
               from the disturbed areas and shall be used in preference to the use of sediment ponds or
               water treatment facilities.

       (2)     Acceptable practices to control sediment and minimize water pollution include, but are
               not limited to:

                      (i) stabilizing disturbed areas through land shaping, berming, contour furrowing
                      or regrading to final contour;

                      (ii) diverting runoff;

                      (iii) achieving quickly germinating and growing stands of temporary vegetation;

                      (iv) regulating channel velocity of water;

                      (v) lining drainage channels with rock or revegetation;


Appendix C                                                                                C-l

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Development Document - Western Alkaline Coal Mining Sub category
                       (vi) mulching;

                       (vii) selectively placing and sealing acid-forming and toxic-forming materials;
                       and

                       (viii) selectively placing waste materials in backfill areas.

        (3)     In addition, unless demonstrated to the Director otherwise, all acceptable practices for
               controlling and minimizing water pollution at underground mines shall include, but not
               be limited to:

                       (i) designing mines to prevent gravity drainage of acid waters;

                       (ii) sealing all underground mine openings;

                       (iii) controlling subsidence; and

                       (iv) preventing acid mine drainage.

        (4)     If the practices listed in paragraph 2009.D(2) are not adequate to meet the requirements
               of paragraph 2009.D(l), the person who conducts  surface coal mining operations shall
               comply with the requirements of Section 2010, unless the Director issues a waiver under
               paragraph 2009.E. [11-29-97]

2009.E The Director may waive the requirements of this Section for regraded areas if the operator can
demonstrate to the Director that the runoff from the regraded area is as good as or better quality than the
waters entering the permit area and erosion from the regraded area has been controlled to the satisfaction
of the Director.

        (1)     To provide for baseline data for waters entering the permit area, the operator shall operate
               and maintain monitoring on all drainages leading into the permit area, in a manner
               approved by the Director, in order to obtain and evaluate occurrences and changes in
               water quality and quantity during the life of mining operations.

        (2)     In order to ensure that runoff from the regraded area is in no way a hazard to the
               environment of the adjacent areas, the waters draining off of the regraded area shall not:

                       (i) exceed the values  of Total Suspended Solids, Iron, Manganese, pH and those
                       parameters listed in paragraph 2009.E(3)(I) from the baseline analyses from the
                       water entering the permit area;

                       (ii) create an increase in  sediment load into the receiving streams;

                       (iii) create any environmental harm or threat to public health and safety; and

                       (iv) degrade, pollute or otherwise diminish the characteristics of existing streams
                       and drainages so as to cause imminent environmental harm to fish and wildlife
                       habitats.
C-2                                                                                     Appendix C

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                                      Development Document - Western Alkaline Coal Mining Sub category
        (3)     Baseline data shall be collected from waters in drainages entering the permit area and
               runoff from regraded areas shall be collected during any precipitation event that produces
               such runoff. The operator shall demonstrate to the Director that the runoff from the
               regraded area has as good as or better chemical quality than the baseline analyses from
               waters entering the permit area.

                      (i) In addition to paragraph 2009.E(2)(I), chemical analysis of the runoff from the
                      regraded area and baseline data from waters entering the permit area shall
                      include, but not limited to, the following parameters:

                      Arsenic (As)          Phosphorus (P)         Carbonate (COS)
                      Boron (B)             Potassium (K)         Bicarbonate (HCO3)
                      Calcium (Ca)          Selenium (Se)         Nitrate (NO3)
                      Chloride              Sodium (Na)           Sulfate (SO4)
                      Cadmium (Cd)         Uranium (U)           Total Dissolved
                      Fluoride               Vanadium (V)          Solids (TDS)
                      Lead (Pb)             Radioactivity          Sodium Adsorption
                      Magnesium (Mg)      Radium Ra226           Ratio (SAR)
                      Radium Ra228

                      (ii) The Director may require additional tests and analyses as he deems necessary.

                      (iii) If the operator can demonstrate that the analysis of any particular parameter
                      are of little  or not significance in the permit or adjacent areas, then such
                      parameter(s) may be waived upon approval by the director.
Appendix C                                                                                  C-3

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Development Document - Western Alkaline Coal Mining Sub category
C-4                                                                                     Appendix C

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                           Development Document - Western Alkaline Coal Mining Sub category
APPENDIX D: Mine Modeling and Performance Analysis - Model
                Input and Output Data
Appendix D

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Development Document - Western Alkaline Coal Mining Sub category
                                                                                        Appendix D

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                                  Development Document - Western Alkaline Coal Mining Sub category
Introduction

       This Appendix contains model input and output data for the mine modeling performed
for NMA using RUSLE version 1.06 and SEDCAD 4.0.  This study was submitted to EPA as
"DRAFT - Western Alkaline Mining Subcategory Mine Modeling and Performance-Cost-
Benefit Analysis" in support of the Western Alkaline Mining Subcategory proposal (WCMWG,
1999c). These data and information support the sedimentology and hydrology modeling results
presented in Section 6, Case Study 1 of this document.  The supporting input and output data for
the RUSLE modeling is presented first (Tables D-l  through D-6) followed by the SEDCAD
output information (Exhibits D-l through D-3)..
RUSLE Version 1.06 Modeling

       Soil loss estimates from a representative model mine were developed using RUSLE
version 1.06.  The backup input and output data are summarized in table form here as:

       • Table D-l:  RUSLE Input Variables For Premining Subwatersheds

       • Table D-2:  Premining RUSLE Model Output

       • Table D-3:  RUSLE Input Variables For Reclaimed Subwatersheds

       • Table D-4:  Input And  Output Variables For Reclaimed Areas

       • Table D-5:  Postmining Reclamation RUSLE Erosion Model Output

       • Table D-6:  Weighted Average Soil Loss Estimates For Disturbed and Reclaimed
                    Subwatersheds (RUSLE)

SEDCAD Version 4.0 Modeling

       Hydrology and  sedimentology data were generated for the model mine under three
scenarios: undisturbed  (premining) conditions; reclamation under current 40 CFR Part 434
guidelines; and reclamation with  alternative BMPs. The supporting reports as produced by
SEDCAD for the three scenarios  are presented in this Appendix:

       • Exhibit D-l: Premining Undisturbed Conditions
       • Exhibit D-2: Postmining Reclaimed Conditions, Existing Guidelines
       • Exhibit D-3: Postmining Reclaimed Conditions, Proposed Subcategory
Appendix D                                                                         D-l

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Development Document - Western Alkaline Coal Mining Sub category
TABLE D-l:   RUSLE Input Variables For Premining Subwatersheds
Reclaimed
Watershed
SW3A
SW3B

SW7

SW9

SW10

SW11

SW13

SW14

SW15

SW17
Subtotal

SW1A
SW1B

SW2

SW4

SW5

SW6

SW8

SW12

SW16

SW18
Subtotal
Total
Reclaimed
Watershed
Area
(acres)
31.2
15.5

25.9

290.0

14.0

15.0

105.3

9.3

30.520

78.5
616.7

44.6
140.1

104.1

75.3

5.5

26.1

23.8

72.6

55.9

23.3
571.3
1188.0
R
30
30

30

30

30

30

30

30

30

30
K
0.29
0.24

0.32

0.24

0.32

0.35

0.27

0.32

0.32

0.36
L
700
435

500

425

500

275

390

300

160

375
S
3.5
5.0

10.0

7.0

6.7

7.1

6.7

5.4

12.5

7.6
C
0.45
0.45

0.45

0.45

0.45

0.45

0.45

0.45

0.45

0.45
P
1.00
1.00

0.47

1.00

1.00

1.00

1.00

1.00

1.00

1.00
Composite
Curve
Number
81
79

88

77

90

91

81

88

88

92
Hydrologic
Condition
C
B

D

B

D

D

C

D

D

D
Acres for subwatershed that will contain 381.8 acres of mining
disturbance.

30
30

30

30

30

30

30

30

30

30

0.37
0.37

0.37

0.35

0.32

0.37

0.37

0.37

0.33

0.32

650
800

850

350

190

250

315

360

440

375

4.5
3.0

2.5

7.0

10.0

8.0

6.3

8.3

8.2

7.0

0.45
0.45

0.45

0.45

0.45

0.45

0.45

0.45

0.45

0.45

1.00
1.00

1.00

1.00

1.00

1.00

1.00

1.00

1.00

1.00

93
93

93

92

88

93

93

93

92

88

D
D

D

D

D

D

D

D

D

D
acres for subwatershed area that will not be disturbed by mining.
acres
D-2
Appendix D

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                                  Development Document - Western Alkaline Coal Mining Sub category
TABLE D-l:  RUSLE Input Variables For Premining Subwatersheds  (Continued)
Reclaimed
Watershed
SW3A
SW3B

SW7

SW9

SW10

SW11

SW13

SW14

SW15

SW17


SW1A
SW1B

SW2

SW4

SW5

SW6

SW8

SW12

SW16

SW18

Soil Type
Loamy Sand
Loamy Sand

Sandy Clay Loam

Loamy Sand

Sandy Clay Loam

Sandy Clay Loam

Loamy Sand

Sandy Clay Loam

Sandy Clay Loam

Sandy Clay Loam


Sandy Clay Loam
Sandy Clay Loam

Sandy Clay Loam

Sandy Clay Loam

Sandy Clay Loam

Sandy Clay Loam

Sandy Clay Loam

Sandy Clay Loam

Sandy Clay Loam

Sandy Clay Loam

Surface Condition
Undisturbed
Undisturbed

Undisturbed

Undisturbed

Undisturbed

Undisturbed

Undisturbed

Undisturbed

Undisturbed

Undisturbed


Undisturbed
Undisturbed

Undisturbed

Undisturbed

Undisturbed

Undisturbed

Undisturbed

Undisturbed

Undisturbed

Undisturbed

Number of
Years to
Consolidate
7
7

7

7

7

7

7

7

7

7


7
7

7

7

7

7

7

7

7

7

General Land
Use
6
6

6

6

6

6

6

6

6

6


6
6

6

6

6

6

6

6

6

6

Appendix D
D-3

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Development Document - Western Alkaline Coal Mining Sub category
TABLE D-2:   Premining RUSLE Model Output
    T MS-DOS Prompt
      filename
      PRE-SH5
      PRE-SH6
      PRE-Sy?
      PRE-SH8
     NOTES:—-
                  	<       1,86 >	
                  Soil Loss     Sediment Vield Computation Worksheet
                                            SDR]   =
                          &8.37
                           •8,37
                          48.45
                          48,45
                          48.45
                          •18,45
                          *f8,45
                          •te.45
                          «t8,45
                          *t8.45
                          48.45
                          48.45
 41. §8
 41.88
 41.88
 *$1.88
 -41.88
 -*i.ee
 **1.88
 **1.88
 41.88
 41.88
 value  entered  directly or file     saved elseihere—
 factor value is  not        upon current factor inputs
 the  field        for  this factor is not current
     1	
                           •
    FUNC esc help clr call info
    f* MS-DOS Prompt
      filename
      PIE-SiS
      PRE-Sili
      PRE-Sill
      PRE~S«16
      PRE-Sil?
      PRE-SilB
     NOTES:—
             t

                 	<       1,96 >	
                  Soil Loss and Sediment Vield Computation Worksheet
                                         I  SDR]  =
                          41.45
                          48.45
                          «t8.45
                          •48.45
                          •*8.45
                          •*8.45
•41.88
                                                 •*1.88
                                                 »*1.88
                                                 -$1.88
           8.32    1.98  «*8.45  «*1.88    §
           1,33    1.27  «*8.45            8
           8.36    1.14  »*8.45            8
 -wo              1.84  -If,45            i
value entered directly or file           elsewhere-
the field       for this factor is not current
                           •
         esc help clr call  info
                                                                              Appendix D

-------
                                  Development Document - Western Alkaline Coal Mining Sub category
TABLE D-3:   RUSLE Input Variables For Disturbed/Reclaimed Subwatersheds
Reclaimed
Watershed
SW3A
SW3B
SW3C
SW3D
SW3E
SW3F
SW3G
SW3H
SW3I
SW7A
SW7B
SW9A
SW9B
SW9C
SW9D
SW9E
SW10
SW11A
SW11B
SW13A
SW13B
SW13C
SW13D
SW13E
SW13F
SW13G
SW13H
SW13I
SW13J
SW14A
SW14B
SW15A
SW15B
SW17A
SW17B
SW17C
SW17D
SW17E
Total
Reclaimed
Watershed
Area
(acres)
20.295
14.907
8.414
11.884
5.500
6.443
14.513
70.798
8.314
9.965
11.735
40.766
7.113
29.932
9.575
30.520
8.058
15.142
13.858
22.100
7.328
13.158
8.547
13.831
9.556
16.221
13.248
12.053
35.792
5.974
4.650
15.352
16.414
3.038
12.123
8.741
10.010
50.821
616.7
R
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30

K
0.29
0.25
0.24
0.15
0.29
0.24
0.24
0.24
0.24
0.24
0.32
0.26
6.3
71.8
36.4
94.6
35.5
59.1
44.3
57.5
22.0
12.8
7.5
13.4
29.6
50.3
60.9
35.0
78.7
16.1
15.3
64.5
72.2
11.5
14.5
8.3
44.0
264.3

L
650
750
250
500
450
400
475
550
250
500
125
340
250
375
400
475
225
500
275
500
100
450
250
250
275
375
385
375
525
300
300
375
600
100
450
450
475
375

S
7.0
3.5
11.0
6.0
6.0
2.6
5.0
2.9
8.2
6.4
8.0
7.3
6.0
5.5
6.4
4.5
7.5
6.0
7.1
5.0
6.4
5.0
6.0
5.0
9.0
6.6
8.0
5.3
3.8
5.4
5.4
7.2
6.4
6.5
6.0
6.0
7.0
7.0

C
0.45
0.45
0.45
0.31
0.05
0.45
0.63
0.49
0.45
0.45
0.45
0.45
0.31
0.48
0.45
0.51
0.45
0.45
0.45
0.45
0.45
0.31
0.31
0.30
0.45
0.55
0.63
0.49
0.47
0.45
0.45
0.45
0.45
0.45
0.31
0.18
0.63
0.45

P
1.00
1.00
1.00
0.47
0.44
1.00
0.45
0.63
1.00
0.69
1.00
1.00
0.47
0.51
0.69
0.72
1.00
0.69
1.00
1.00
1.00
0.47
0.47
0.45
0.46
0.47
0.47
0.63
0.67
0.69
1.00
0.69
1.00
1.00
0.47
0.45
0.47
1.00

Composite
Curve
Number
80
79
79
65
74
79
74
74
79
74
88
80
65
74
74
74
92
74
91
79
81
65
65
74
74
74
74
74
74
74
88
74
88
93
74
74
74
92

Hydrologic
Condition
B
B
B
A
B
B
B
B
B
B
D
C
A
B
B
B
D
B
D
B
C
A
A
B
B
B
B
B
B
B
D
B
D
D
B
B
B
D

Appendix D
D-5

-------
Development Document - Western Alkaline Coal Mining Sub category
TABLE D-3:  RUSLE Input Variables For Disturbed/Reclaimed Subwatersheds
              (Continued)
Reclaimed
Watershed
SW3A
SW3B
SW3C
SW3D
SW3E
SW3F
SW3G
SW3H
SW3I
SW7A
SW7B
SW9A
SW9B
SW9C
SW9D
SW9E
SW10
SW11A
SW11B
SW13A
SW13B
SW13C
SW13D
SW13E
SW13F
SW13G
SW13H
SW13I
SW13J
SW14A
SW14B
SW15A
SW15B
SW17A
SW17B
SW17C
SW17D
SW17E

Soil Type
Loamy Sand
Loamy Sand
Loamy Sand
Loamy Sand
Loamy Sand
Loamy Sand
Loamy Sand
Loamy Sand
Loamy Sand
Loamy Sand
Sandy Clay Loam
Loamy Sand
Loamy Sand
Loamy Sand
Loamy Sand
Loamy Sand
Sandy Clay Loam
Loamy Sand
Sandy Clay Loam
Loamy Sand
Loamy Sand
Loamy Sand
Loamy Sand
Loamy Sand
Loamy Sand
Loamy Sand
Loamy Sand
Loamy Sand
Loamy Sand
Loamy Sand
Sandy Clay Loam
Loamy Sand
Sandy Clay Loam
Sandy Clay Loam
Loamy Sand
Loamy Sand
Loamy Sand
Sandy Clay Loam

Surface Comdition
Undisturbed
Undisturbed
Undisturbed
Spoil, backfilled & graded
Topdressed, straw mulched & seeded
Undisturbed
Reveg. 1-3 Years
Reveg. 4-8 years/some reveg. 1-3 years
Undisturbed
Reveg. 4-8 years
Undisturbed
Undisturbed
Spoil, backfilled & graded
Reveg. 1-3 Years/some topdressed area
Reveg. 4-8 years
Reveg. 4-8 years/some 1-3 years/some undisturbed
Undisturbed
Reveg. 4-8 years
Undisturbed
Undisturbed
Undisturbed
Spoil, backfilled & graded
Spoil, backfilled & graded
Topdressed/some reveg. 1-3 years
Reveg. 1-3 Years/some topdressed area
Reveg. 1-3 Years/some topdressed area
Reveg. 1-3 Years/some reveg. 4-8 years
Reveg. 4-8 Years/some reveg. 1-3 years
Reveg. 4-8 Years/some reveg. 1-3 years
Reveg. 4-8 Years
Undisturbed
Reveg. 4-8 Years/some reveg. 1-3 years
Undisturbed
Undisturbed
Spoil, backfilled & graded
Topdressed/some reveg. 1-3 years
Reveg. 1-3 years/some topdressed/some spoil
Undisturbed/some reclaimed

Number of
Years to
Consolidate
7
7
7
10
10
7
10
10
7
10
7
7
10
10
10
10
7
10
7
7
7
10
10
10
10
10
10
10
10
10
7
10
7
7
10
10
10
7

General
Land Use
6
6
6
10
8
6
8
8
6
8
6
6
10
8
8
8
6
8
6
6
6
10
10
8
8
8
8
8
8
8
6
8
6
6
10
8
8
6

D-6
Appendix D

-------
                                        Development Document - Western Alkaline Coal Mining Sub category
TABLE D-4:   RUSLE Model Input And Output Variables For Reclaimed Areas
'« Ml-BOS

Auto jj ri i* n,


5 	 A] 	


Area Filename

SPOIL



TOPDRESS



REVEG1-3
REVEG1-4
Description

Mine spoil backfilled and graded, consisting of loamy sand overburden; CN = 65; k = 0.15;
hydrologic condition = A; 25% gravel, 10% cobble, 5% rock fragments; slow hydrologic
response time.

Area topdressed, consisting of loamy sand topsoil; roughened with contour furrows; straw
mulched (2 tons/acre); recently seeded with no growth started; CN = 74; k = 0.24;
hydrologic condition = B; medium hydrologic response time.

Area originally prepared the same as previous topdressed area;  1-3 years  of vegetative
growth; surface  roughening  slightly  decreased from erosion,  sedimentation,  and
consolidation; CN = 74, k = 0.24; hydrologic condition = B; medium hydrologic response
time.

Area originally prepared the same as previous topdressed area;  4-8 years  of vegetative
growth typically  more dense than area with 1-3 years of vegetative growth;  surface
roughening continuing to decrease from erosion, sedimentation, and consolidation; CN = 74,
k = 0.24; hydrologic condition = B; medium hydrologic response time.
Appendix D
                                                                         D-7

-------
Development Document - Western Alkaline Coal Mining Sub category
         TABLE D-5:   Postmining Reclamation RUSLE Erosion Model Output
         ri MS-DOS Pinup!
       tf MS-DOS Prompt
          filename
          PSTSW7A
          SSTSW7B

          58TBWPB


          SiTSWil
          5STSW10
          SSTiWllA
          BBTBW11B
        MOTEB;	*
                      	< RUSLE l.Oi  >	
                      Soil Loss      iediment Yield Computation Worksheet
                   Li   x   C   X

           0.24
           0.32
           0,24
          *O.Z4
 J.45
*0.45
*0,45
 0.31
*0.4B
 0,45
*0.51
*0.45
 0.45
*0.45
 1.00
 1,00
 0.47
*0.51
*0.69
*0.7Z
 1.00
 0.69
 1.00
ralue entered dicectlT or file     saved  els<
       •I
       FUHC      help clr call  info
D-8
                                                    Appendix D

-------
                                         Development Document - Western Alkaline Coal Mining Sub category
     .!•! MS-DOS Prompt
H Piompl

Auto jj I"l
%•
^P,


Aj

*iiiiiiiiiiiiiiiiiiiiiiii^^
Appendix D
D-9

-------
Development Document - Western Alkaline Coal Mining Sub category
TABLE D-6:  Weighted Average Soil Loss Estimates For Undisturbed And Reclaimed
Watersheds (RUSLE)
LJN DISTURBED WATERSHED
Undisturbed
Watershed
SW3A
SW3B






SW7


SW9




SW10
SW11

SW13









SW14

SW15

SW17




Totals
Undisturbed
Watershed
Area
(acres)
31.2
15.5






25.9


290.0




14.0
15.0

105.3









9.3

32.0

78.5




616.7
Average
Annual
Soil Loss
(tons/acre)
2.2
3.6






7.5


4.5




4.5
4.7

4.0









3.3

8.2

5.6





Average
Annual
Soil Loss
(tons)
68.7
55.8






194.2


1305.0




63.1
70.6

421.2









30.7

262.0

439.6




2911.0
Weighted Average Soil Loss = 4.7 tons/acre/yr.
RECLAIMED WATERSHED
Reclaimed
Watershed
SW3A
SW3B
SW3C
SW3D
SW3E
SW3F
SW3G
SW3H
SW3I
SW7A
SW7B
SW9A
SW9B
SW9C
SW9D
SW9E
SW10
SW11A
SW11B
SW13A
SW13B
SW13C
SW13D
SW13E
SW13F
SW13G
SW13H
SW13I
SW13J
SW14A
SW14B
SW15A
SW15B
SW17A
SW17B
SW17C
SW17D
SW17E

Reclaimed
Watershed
Area
(acres)
20.3
14.9
8.4
11.9
5.5
6.4
14.5
70.8
8.3
10.0
11.7
40.8
7.1
29.9
9.6
30.5
8.1
15.1
13.9
22.1
7.3
13.2
8.5
13.8
9.6
16.2
13.2
12.1
35.8
6.0
4.7
15.4
16.4
3.0
12.1
8.7
10.0
50.8
616.7
Average
Annual
Soil Loss
(tons/acre)
4.8
1.9
5.9
1.3
0.27
1.2
2.7
1.5
3.9
4.2
4.3
4.0
0.88
2.4
3.8
3.1
4.4
3.9
3.2
2.6
3.0
0.97
0.88
0.97
3.1
3.1
4.6
2.9
2.2
2.7
3.3
4.2
4.4
3.8
1.2
0.95
4.4
5.2

Average
Annual
Soil Loss
(tons)
97.4
28.3
49.6
15.4
1.5
7.7
39.2
106.2
32.4
41.9
50.5
163.1
6.3
71.8
36.4
94.6
35.5
59.1
44.3
57.5
22.0
12.8
7.5
13.4
29.6
50.3
60.9
35.0
78.7
16.1
15.3
64.5
72.2
11.5
14.5
8.3
44.0
264.3
1859.8
Weighted Average Soil Loss = 3.0 tons/acre/yr.
D-10
Appendix D

-------