EPA AND HARDROCK MINING:

A SOURCE BOOK FOR INDUSTRY IN THE NORTHWEST AND ALASKA

January 2003

U.S. Environmental Protection Agency

Region 10

1200 6th Avenue

Seattle, Washington 98101
EPA and Hardrock Mining: A Source Book for Industry in the Northwest and Alaska

i January 2003

TITLE AND DISCLAIMER

Title

Title: EPA and Hardrock Mining: A Source Book for Industry in the Northwest and

Alaska

Prepared by: EPA Region 10 with the technical assistance of Science Applications

International Corporation

Date: January 2003

Disclaimer

 This document is not intended, nor can it be relied on, to create any rights enforceable by any

party in litigation with the United States. Any mention of company or product name is not to be

considered an endorsement by the U.S. Government or by the Environmental Protection Agency. 

 This document describes information needed by EPA to evaluate and make regulatory decisions

on hardrock mines; as a result, the document is general in nature and applicants should not view

anything in this guidance as ‘mandatory’ or prescriptive. A draft of this document was made

available for review by Federal and State agencies, by public interest groups, and by interested

members of the public. EPA then revised the draft and prepared this final document by

addressing those comments as deemed appropriate by EPA. Commenters are identified, and

both comments and EPA responses to those comments, are presented in Appendix J. 
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TABLE OF CONTENTS

Section Page

TABLE OF CONTENTS ........................................................... i

LIST OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

LIST OF FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

LIST OF APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

1.0 INTRODUCTION ...........................................................1

1.1 Purpose of this Document ..............................................1

1.2 Problem Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.3 General Suggestions for Completing the Permitting Process ...................2

1.4 Organization of this Source Book . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2.0 INTRODUCTION TO NPDES PERMITTING (CWA SECTION 402) ......................4

2.1 When is an NPDES Permit Needed? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.2 Technology-based National Effluent Limitation Guidelines . . . . . . . . . . . . . . . . . . . 10

2.3 Water Quality Standards and Water Quality-Based Permitting . . . . . . . . . . . . . . . . 11

2.4 Storm Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2.5 Information Needs for NPDES Permitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

3.0 DISCHARGE OF DREDGED OR FILL MATERIAL TO WATERS OF THE U.S. (SECTION 404) . . . 20

4.0 THE NATIONAL ENVIRONMENTAL POLICY ACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

4.1 EPA’s NEPA Role . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4.2 EPA Requirements for Environmental Review Under NEPA and the CWA . . . . . . 24

4.3 When is an EIS Required? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

5.0 OTHER AUTHORITIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

5.1 Clean Air Act . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

5.1.1 New Source Performance Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

5.1.2 Specific Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

5.2 Endangered Species Act . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

5.3 Resource Conservation and Recovery Act . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

5.4 Coastal Zone Management Act . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

5.5 State Authorities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

TABLE OF CONTENTS

(continued)
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6.0 EPA EXPECTATIONS FOR MINING IMPACT ASSESSMENT . . . . . . . . . . . . . . . . . . . . . . . . . . 39

6.1 Impacts to Surface and Ground Water Hydrology . . . . . . . . . . . . . . . . . . . . . . . . . . 39

6.1.1 Surface Water Hydrology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

6.1.2 Ground Water Hydrogeology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

6.2 Impacts to Water Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

6.2.1 Background and Existing Water Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

6.2.2 Regional Hydrology and Hydrogeology . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

6.2.3 Hydrology of Mines and Waste Facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

6.2.4 Solid Waste and Materials Characterization and Management . . . . . . . . . . 48

6.2.5 Wastewater Quality and Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

6.2.6 Post-Closure Mine and Waste Facility Water Quality . . . . . . . . . . . . . . . . . . 51

6.2.7 Closure and Reclamation Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

6.3 Impacts to Aquatic Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

6.4 Impacts to Wetlands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

7.0 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

LIST OF TABLES

Table 1. Categories of Discharges from Mines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Table 2. Industry Sectors and Types of Applicable Limits 40 CFR Part 440 . . . . . . . . . . . . . 12

Table 3. Selected Definitions and Provisions in 40 CFR Part 440 . . . . . . . . . . . . . . . . . . . . . 12

Table 4. EPA Forms Required for NPDES Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Table 5. Overview of Information Needs for NPDES Permitting . . . . . . . . . . . . . . . . . . . . . . 20

Table 6. Potential Emission Sources at Mine Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Table 7. Delegation and Authorization of Federal Environmental Programs 

to States in EPA Region 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Table 8. Data Needs for NEPA Review and CWA Permits . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Table 9. Testing Needs for NEPA Review and CWA Permits . . . . . . . . . . . . . . . . . . . . . . . . 42

Table 10. Preliminary Design Needs for NEPA Review and CWA Permits . . . . . . . . . . . . . . . 43

Table 11. Data Analysis Needs for NEPA Review and CWA Permits . . . . . . . . . . . . . . . . . . . 44

LIST OF FIGURES

Figure 1. NPDES Permitting Process .............................................6

Figure 2. Example of Discharge Classification Depending on Wastewater 

Source and Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Figure 3A. Informal Consultation Under the Endangered Species Act . . . . . . . . . . . . . . . . . . . . 33

Figure 3B. Formal Consultation Under the Endangered Species Act . . . . . . . . . . . . . . . . . . . . . 34

LIST OF APPENDICES

A Hydrology

B Receiving Waters
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C Characterization of Ore, Waste Rock, and Tailings

D Effluent Quality

E Wastewater Management

F Solid Waste Management

G Aquatic Resources

H Erosion and Sedimentation

I Wetlands

J Comments on Draft Source Book
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EPA and Hardrock Mining: A Source Book for Industry in the Northwest and Alaska

1

This Source Book is intended to address “hardrock” mines but not placer mines or sand and

gravel operations.

1 January 2003 1

1.0 INTRODUCTION

1.1 Purpose of this Document

This ‘Source Book’ was prepared by the Environmental Protection Agency (EPA) Region

10 to provide guidance on the Clean Water Act (CWA) permitting processes and associated

National Environmental Policy Act (NEPA) environmental review requirements for new metal

mining operations in Alaska, Idaho, Oregon, and Washington.1 This guidance has three specific

purposes. First, it is intended to explain the specific requirements of the CWA as they may

pertain to new mines. It is hoped that a better understanding of EPA’s mandates and authorities

will provide a basis for understanding why certain information is often requested as part of the

CWA permitting processes. Second, this document describes the types of information that EPA

Region 10 generally needs to process permit applications and perform environmental reviews in

an efficient and timely manner. By articulating these information needs, EPA hopes that the

mining industry will realize time and cost savings during the permitting process by avoiding

surprises, false starts, and the need for additional gathering and/or analysis of technical data. 

Finally, the guidance is intended to promote predictability and consistency within Region 10 to

ensure mine development, operation, and closure occur in an environmentally sound manner.

Given the unique character of each mining operation and the wide variety of environments

in which they may operate, it is impractical for the Region to develop specific detailed

instructions that would apply to all sites. Consequently, this document is general in nature and

applicants should not view anything in this guidance as ‘mandatory’ or prescriptive. However,

there are several questions that follow naturally from the discussions contained herein and that

will be asked of most applicants. Among the most important are: Will there be a discharge of

wastewater during operations and/or closure? Will the discharge meet water quality standards? 

What is the long-term risk of surface and ground water contamination? Will reclamation restore

the integrity of aquatic and terrestrial ecosystems affected by the project? How can unacceptable

environmental impacts be avoided or mitigated? 

1.2 Problem Statement

There is general agreement among interested parties that it is becoming increasingly

difficult to permit new mines. Mining operations typically are complex undertakings that may

be situated in or near complex and sensitive environments. Predicting how a particular mine

may affect the environment during its active life and following closure is no simple task. In EPA

Region 10, new mines present a significant challenge for those who develop CWA Section 402

National Pollutant Discharge Elimination System (NPDES) permits, review public notices and

mitigation plans for CWA Section 404 Dredge and Fill permits, and review or prepare

Environmental Impact Statements (EISs) pursuant to the National Environmental Policy Act

(NEPA). Common pitfalls and problems at mines in Region 10 include water balances that do
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not properly bracket high and low flows, underestimating water treatment needs, using

laboratory detection limits that are too high, using inappropriate modeling approaches, failure to

consider temporary shutdowns and post-closure scenarios, and overall data quality problems

(e.g., non-representative samples). The challenge lies largely in determining with a reasonable

degree of certainty what measures are needed to assure that a technically complex operation,

which is often highly exposed to the variable forces of nature, will remain in compliance with

applicable laws and regulations throughout active mining as well as during and following

closure.

EPA Region 10 encompasses Alaska, Washington, Oregon, and Idaho, states with

environments that range from temperate coastal rainforest to alpine mountain tundra to semi-arid

high plateau to Arctic Ocean. Methods to characterize such diverse environments vary widely,

often depending on how much information is readily available for a particular location. Also,

these environments provide habitat to a range of threatened, endangered, and sensitive species,

including several species of anadromous fish (e.g., salmon, steelhead). As such, the CWA

permitting processes often require consultation pursuant to the Endangered Species Act (ESA)

with the U.S. Fish and Wildlife Service (USFWS) and/or the National Marine Fisheries Service

(NMFS). This can be a time-consuming process. Since much of the mining that occurs in

Region 10 is located on Federal lands administered by the U.S. Forest Service, Bureau of Land

Management, and National Park Service, proper coordination with these Federal land

management agencies, who more often than not have the lead for EIS preparation, is also

necessary to ensure a smooth process. Mining also may occur on State land and Tribal land in

any of the states in Region 10. Regardless of land ownership and mineral or other land use

rights, there are often numerous authorities at these levels that must be integrated into the overall

permitting of any proposed mine. It is hoped that this document will be helpful to these agencies

in understanding EPA’s authorities, information, and coordination needs in order to reach permit

decisions in a timely manner.

1.3 General Suggestions for Completing the Permitting Process

 Many applicants may feel that CWA permitting and associated NEPA processes are tests

of endurance. This does not have to be the case. In EPA Region 10's experience, many

applicants who encounter delays in acquiring mine permits have either not provided the types of

data and analyses to demonstrate how their proposed operation may affect the environment

during and after operation and/or they have not adequately considered feasible options that may

be more “environmentally friendly.” A common problem is that applicants do not collect data

that satisfy the environmental permitting process. For example, metal constituents in surface

water samples may be measured using methods with detection limits that are higher than water

quality criteria values. Other examples would be when geochemical or hydrological and

hydrogeological studies are conducted only to satisfy objectives associated with mine

development and not to help evaluate potential environmental impacts as well. 

Applicants can help to minimize delays during NEPA and CWA permit application

processes by considering the following general suggestions:
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• Evaluate possible environmental data requirements and initiate environmental

planning on the front end. 

• Collect data to meet specific environmental objectives or requirements, and collect

them at the required levels of detail and precision.

• Provide adequate data and analyses for all proposed alternatives.

• Be flexible when choosing facility designs, locations, and technologies.

• Propose use of treatment, disposal, and reclamation technologies with demonstrated

records of success.

• Use appropriately conservative and justifiable assumptions and interpretations.

• Be pro-active in resolving potential environmental problems.

• Establish open lines of communication with the federal and state regulatory and land

management agencies that will oversee the processing of the permit application(s)

very early in the process, not after data are collected and planning is near completion. 

Maintain these lines of communication throughout the review and permitting process,

and then throughout the life of the mine as well as through the closure phase. 

• Review data collection plans and data quality objectives with the appropriate

regulatory agency prior to gathering the data.

Because the CWA permitting and NEPA review processes typically require an applicant to

provide a variety of data at different levels of detail and precision, applicants are likely to realize

cost savings by evaluating their potential data needs from the outset of a proposed project. This

will enable a complete and coherent set of data to be collected efficiently and at the required

levels of precision, while avoiding data gaps or overlap. In order to specifically evaluate

potential impacts to surface and ground water resources, applicants may need to study an area

larger than that required for the mining operation; a common approach is to use a watershed

perspective.

Applicants are encouraged to evaluate different mine layouts, facility designs, and

technologies in an effort to minimize the potential for environmental impact during and

following operation. If newly developed or unproven treatment or disposal technologies are

proposed to be used, applicants can expect to be asked to provide the results of bench- or pilotscale tests conducted to evaluate the effectiveness of the technology and to institute more

detailed monitoring to demonstrate their effectiveness. 

Finally, applicants will find that impact analyses often require assumptions of future

conditions, waste behavior, and land uses. This is especially true for interpretations,

extrapolations, and modeling of geochemical test results and site hydrology evaluations (e.g.,

water balances). In all cases, applicants should aim to be conservative in their judgment of
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future conditions and waste behavior and be able to justify their assumptions and interpretations. 

As with data collection, applicants are strongly encouraged to discuss sampling and data analysis

plans, including assumptions and uncertainties, with the appropriate regulators prior to

performing the analyses.

1.4 Organization of this Source Book

The remainder of the main text of the source book describes the major environmental

programs that apply to hardrock mining, and the types of information that EPA needs in order to

issue permits, conduct reviews, and otherwise fulfill its legal obligations. Sections 2.0 and 3.0

describe Clean Water Act programs: section 2.0 provides an overview of NPDES permitting,

including many of the major components of the NPDES program, and section 3.0 describes the

§404 program, under which dredge and fill activities are permitted. Section 4.0 covers the

National Environmental Policy Act, which requires an analysis of the environmental impacts of

proposed Federal actions, including the issuance of permits. Section 5.0 covers the requirements

of the Clean Air Act and the Endangered Species Act. Finally, section 6.0 summarizes the types

of effects that mining can have, and the types of analyses and information that EPA expects from

project proponents in applications for permits and in documents and other materials that have to

be reviewed and/or approved by EPA. 

The Source Book includes nine technical appendices that describe the major issues that

must be understood and addressed in order to understand and control the impacts from mining

operations. Technical appendices include the following:

• Appendix A: Hydrology

• Appendix B: Receiving Waters

• Appendix C: Characterization of Ore, Waste Rock, and Tailings

• Appendix D: Effluent Quality

• Appendix E: Wastewater Management

• Appendix F: Solid Waste Management 

• Appendix G: Aquatic Resources

• Appendix H Erosion and Sedimentation

• Appendix I Wetlands

2.0 INTRODUCTION TO NPDES PERMITTING (CWA SECTION 402)

The objective of the Clean Water Act is to “restore and maintain the chemical, physical,

and biological integrity of the Nation's waters” (§101(a)). This is to be accomplished through

the control of both point and nonpoint sources of pollution (§101(a)(7)). A number of

interrelated provisions of the Act establish the structure by which the goals of the Act are to be

achieved. Within this overall structure, a variety of Federal and State programs are implemented

to meet the Act's requirements. Under Section 402 of the Clean Water Act, all point source

discharges (see Section 2.1 for definitions) of pollutants to navigable waters of the United States

must be permitted under the National Pollutant Discharge Elimination System (NPDES). 

NPDES permits are issued by EPA or authorized states. In Region 10, Oregon and Washington

are currently authorized to implement the NPDES program, and these states issue NPDES
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permits that are subject to EPA review. EPA is responsible for issuing NPDES permits in Idaho

and Alaska. 

Figure 1 shows the NPDES permitting process. The process is summarized in the

following text. The time required to complete each step in Figure 1 varies widely and depends

on a number of factors, notably the timeliness and completeness of information provided by the

applicant. Readers are referred to the U.S. EPA NPDES Permit Writers’ Manual (EPA 1996) for

more information. The primary regulations developed by EPA to implement and administer the

NPDES Program are found in 40 CFR Part 122.

The NPDES application process formally begins upon submission of the application to

EPA Region 10 and proceeds through a number of steps required by 40 CFR 122. Prospective

applicants are encouraged to correspond with and, if appropriate, meet with Region 10 staff prior

to preparing and submitting the application. Application requirements are prescribed in 40 CFR

122.21, but it is always beneficial if an open dialogue is established early to ensure that

information needs are fully met, particularly information that supports both the NPDES program

and NEPA. This is especially true for large complex operations, proposed operations in sensitive

environments or on water quality-limited waters, or where there may be special concerns by EPA

or other agencies. 

In general, applicants must submit an application at least 180 days prior to discharge or

permit expiration, or if a new source, prior to construction (see Section 2.1 for definition of a

new source). Section 2.5 provides a summary of the information EPA typically expects to be

submitted with the application. Upon receipt of an NPDES permit application, EPA conducts an

initial review for completeness. In the past, EPA has found that initial applications found to be

significantly incomplete inevitably result in delays in the permitting process.

Upon finding that an NPDES permit application is complete, EPA begins determining draft

permit limits and conditions. The following summarizes the major components included in

NPDES permits. 

• Identification and authorization of the discharge.

• Effluent limitations. Effluent limitations are restrictions on the quantity, rates, and/or

concentrations of pollutants that are discharged from point sources. Effluent limits are

either technology-based (based on technology-based effluent limitation guidelines) or

water quality-based (based on water quality standards). In determining the need for

effluent limits, EPA assesses the applicable technology-based limits and the potential

for exceedances of water quality standards. Because data supplied by the permittee is

critical in developing effluent limitations and most of the permit writer’s time is spent 

in developing effluent limitations, the processes for developing effluent limitations are

described in Sections 2.3 (technology-based limits) and 2.4 (water quality-based

permitting). 
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Figure 1. NPDES Permitting Process
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• Monitoring and reporting requirements. Permittees are required to monitor waste

streams and receiving waters to allow EPA (and/or states) to monitor changes in water

quality, to evaluate wastewater treatment efficiency, and determine compliance with

permit limits.

• Special Conditions. Conditions are developed to supplement effluent limitations. 

Examples include best management practices (BMPs), additional monitoring

activities, ambient stream surveys, etc.

• Standard Conditions. Pre-established conditions are included in all NPDES permits. 

These conditions delineate the legal, administrative, and procedural requirements of

the NPDES permit.

To accompany each draft permit, EPA prepares a fact sheet that provides facility

background information, describes anticipated discharge composition and flow, describes

receiving waters, and provides the basis for the proposed effluent limitation(s), monitoring

requirements, and other permit conditions. The fact sheet also documents that the permit

complies with other applicable statutes (e.g., the Endangered Species Act and Coastal Zone

Management Act). 

Draft permits are subject to a public comment period of at least 30 days. If requested by

interested parties, EPA may hold a public hearing. At the end of the public comment period,

EPA prepares a final permit along with supplementary documentation that responds to public

comments. The final permit then includes an effective date after which the permittee must

comply with all permit requirements. NPDES permits, whether issued by EPA or an authorized

state, have a clear expiration date, which may be up to five years after issuance. Prior to the

expiration date, permittees need to apply for new permits.

Before EPA can issue a permit in Idaho or Alaska, the state must certify that the discharge

authorized in the permit will comply with state water quality standards (this is known as a 401

certification after the CWA section that requires it). Section 2.3 discusses state water quality

standards provisions important to permitting.

 

EPA is not obligated to issue an NPDES permit to any mine operator. EPA may reject a

permit application if the agency believes that discharges would not comply with Clean Water

Act provisions and/or anticipated permit conditions. For example, EPA would not issue a permit

to facility where proposed discharges are not expected to meet technology- or water qualitybased effluent limitations (see 40 CFR 122.4 Prohibitions). 

The following sections describe key aspects of the NPDES permitting process for mining

discharges. Section 2.1 describes when an NPDES permit is needed. Section 2.2 discusses the

technology-based effluent limitation guidelines which are national standards that apply to

effluent discharges from hardrock mines. Section 2.3 summarizes key aspects of water quality

standards related to NPDES permitting and describes how water-quality based effluent limits are

developed. Section 2.4 describes storm water permitting and Section 2.5 provides an overview

of the information that EPA needs in order to issue an NPDES permit. 
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Because of the complexities and site-specific factors associated with projecting NPDES

permit requirements, EPA strongly recommends that mine operators coordinate with EPA and

states early in the planning process. This will assist in evaluating options for wastewater

management practices and identifying NPDES information needs.

2.1 When is an NPDES Permit Needed?

As noted in Section 2.0, NPDES permits are required for any discharge of pollutant from a

point source to waters of the U.S. The term "point source" is defined very broadly under the

Clean Water Act, in part because it has been refined through over 25 years of litigation. It means

any discernible, confined and discrete conveyance, such as a pipe, ditch, channel, tunnel,

conduit, discrete fissure, or container (see 40 CFR 122.2). Similarly, the term "water of the

U.S." is defined very broadly under the Clean Water Act and through years of litigation. It

means navigable waters, tributaries to navigable waters, interstate waters, the oceans out to 200

miles, and intrastate waters which are used by interstate travelers for recreation or other

purposes, as a source of fish or shellfish sold in interstate commerce, or for industrial purposes

by industries engaged in interstate commerce.

Given these broad definitions, nearly any discharge from a mine could be considered a

point source. In general, three discrete categories of discharges from mining operations require

NPDES permits: process wastewater, mine drainage, and storm water. Definitions of each are

provided in Table 1. Notably, tailings may not be discharged into water of the U.S., including

marine waters. NPDES permit applicants are encouraged to communicate with EPA or an

authorized state to determine how to categorize discharges and to discuss the permitting process. 

For new dischargers, EPA’s NPDES regulations [40 CFR § 122.21(a)] require prospective

dischargers (in States without an approved NPDES program) to submit, prior to beginning onsite

construction, information to the EPA Region that will allow a determination by EPA of whether

the facility is a “new source”. “New source” is defined as any building, structure, facility, or

installation from which there is or may be a discharge of pollutants, the construction of which

commenced after promulgation of applicable new source performance standards (see Section 2.2

for discussion of new source performance standards). Specific criteria that EPA uses to

determine whether or not a discharge is a new source are in 40 CFR § 122.29. In general, most

new mining operations are defined as new sources. Construction at existing facilities may

represent a new source depending upon the age of the facility. 

If the facility is determined to be a new source, 40 CFR 122.29(c) provides that the

issuance of the NPDES permit is subject to the environmental review requirements of NEPA,

and thus to EPA’s NEPA regulations at 40 CFR Part 6 Subpart F. In cases where NEPA applies,

EPA expects the permit applicant to begin the environmental review process by preparing an

Environmental Information Document (EID) with the NPDES permit application (see Section

4.0). In preparing a draft new source NPDES permit, the administrative record on which the
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Table 1. Categories of Discharges from Mines

Process wastewater “...any water which, during manufacturing or processing, comes into direct

contact with or results from the production or use of any raw material,

intermediate product, finished product, byproduct, or waste product.” (40

CFR 122.22)

See Section 2.3 for discussion of effluent limitation guidelines applicable to

process wastewaters.

Mine drainage “...any water drained, pumped, or siphoned from a mine.” (40 CFR

440.132) [See Table 3 for definition of “mine.”]

See Section 2.3 for discussion of effluent limitation guidelines applicable to

mine drainage.

Storm water (associated

with industrial activity)

“... the discharge from any conveyance which is used for collecting and

conveying storm water and which is directly related to manufacturing,

processing or raw materials storage areas at an industrial plant. ...[T]he

term includes, but is not limited to, storm water discharges from industrial

plant yards; immediate access roads and rail lines used or traveled by

carriers of raw materials, manufactured products, waste material, or

byproducts used or created by the facility; material handling sites; refuse

sites; sites used for the application or disposal of process waste waters (as

defined at 40 CFR part 401); sites used for the storage and maintenance

of material handling equipment; sites used for residual treatment, storage,

or disposal; shipping and receiving areas; manufacturing buildings; storage

areas (including tank farms) for raw materials, and intermediate and

finished products; and areas where industrial activity has taken place in the

past and significant materials remain and are exposed to storm water....

For the purposes of this paragraph, material handling activities include the

storage, loading and unloading, transportation, or conveyance of any raw

material, intermediate product, finished product, byproduct or waste

product. The term excludes areas located on plant lands separate from the

plant’s industrial activities, such as office buildings and accompanying

parking lots as long as the drainage from the excluded areas is not mixed

with storm water drained from the above described areas.” (40 CFR

122.26(b)(14). Note that a permit is NOT required for “...discharges of

storm water runoff from mining operations ... which are not contaminated

by contact with or that has not come into contact with, any overburden, raw

material, intermediate products, finished product, byproduct or waste

products located on the site of such operations.” (40 CFR 126(a)(2))

See Section 2.4 for a discussion of storm water permitting.

 draft permit is based must include the EID prepared by the applicant, the environmental

assessment (and, if applicable, the FNSI) prepared by EPA, and/or the environmental impact

statement (EIS) or supplement, if applicable. In addition, public notice for a draft new source

NPDES permit for which an EIS must be prepared cannot take place until the draft EIS is issued

[40 CFR Part 124.10(b)]. It is also important for applicants to recognize that 40 CFR 122.4(i)

prohibits issuance of a NPDES permit to a new source or a new discharger if the discharge from

its construction or operation will cause or contribute to the violation of water quality standards. 

Thus EPA places a very strong emphasis on demonstrating within the NEPA process that the

proposed mining operation will be able to comply with applicable water quality standards during

construction, operation and through closure.
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10 January 2003 10

2.2 Technology-based National Effluent Limitation Guidelines

Section 301(b)(2) of the Clean Water Act requires technology-based controls on effluents.

These technology-based controls are established in effluent limitation guidelines (ELGs). 

Section 304(b) of the Clean Water Act requires EPA to promulgate regulations providing ELGs

that set forth the degree of effluent reduction attainable through the application of the "best

practicable control technology currently available" (BPT) and the "best available technology

economically achievable" (BAT). For new industrial dischargers (new sources), §§304(c) and

306 require EPA to promulgate "new source performance standards" (NSPS) based on "best

available demonstrated technology." To move toward the Act's goals of eliminating the

discharge of all pollutants, existing industrial discharges were required to achieve these ELGs by

specific dates: BPT ELGs by 1977 and BAT by 1983. All new sources are required to meet

NSPS from their inception. 

The current ELGs for the ore mining and dressing industry were promulgated by EPA in

1978 (BPT) and 1982 (BAT and NSPS). The ELGs for the ore mining and dressing industry are

found at 40 CFR Part 440, which applies generally to facilities classified with Standard

Industrial Classification (SIC) code 10; this includes and is limited to the mining and milling of

metalliferous ores (this discussion does not include placer gold mines, for which the ELGs at 40

CFR Part 440 Subpart M were promulgated in 1989 and take a somewhat different form than the

rest of Part 440). Other than gold placer mining, EPA has divided the ore mining and dressing

category into 11 subcategories based on the type of ore mined and milled. The subcategories for

which EPA has established ELGs for one or more types of discharges are shown in Table 2. 

For the various subcategories, there are ELGs for two types of discharges: "mine drainage"

and “process” wastewater. The latter generally includes effluent from mills (such as water

contained in tailings) and other concentration (or, in RCRA terms, “beneficiation”) operations,

such as dump and heap leach operations. See Table 1 for definitions of mine drainage and

process wastewater. The ELGs specify numeric limitations, and contain various applicability

conditions and exemptions. For certain mills in some subcategories, the NSPS ELGs allow no

discharge except in net precipitation areas, where so-called “zero discharge” facilities may

discharge only the volume of water that represents the excess of annual precipitation over annual

evaporation. Under certain conditions, Part 440 provides a "storm exemption" from applicable

ELGs for discharges from qualifying facilities in all subcategories. Tables 2 and 3 provide an

overview of the requirements of Part 440. Table 2 shows the types of ELGs that have been

promulgated for the various subcategories and the types of limits established for these categories. 

Table 3 presents certain definitions (e.g., of "mine”) as well as a summary of the storm

exemption. 

It is worth noting that ELGs are established for only a limited number of the pollutants that

are likely or known to be present in the discharge from metal mines and mills (for example, the

ELGs establish concentration limits for only one or a few metal pollutants, although a suite of

heavy metals may generally co-occur in discharges). Compliance with the ELGs is intended to

ensure that other metals present in the discharge are adequately treated. The ELGs’ technologybased concentration levels are considered the baseline for discharges. 
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11 January 2003 11

A semantic distinction is also worth noting. Although the ELGs establish technologybased limits, neither the ELGs nor other regulations require the use of any particular technology,

and this fact is often misunderstood. Rather, the ELGs require that discharges achieve at least a

comparable level of treatment as the technology on which the limit is based. 

Any applicable limitations and conditions that are specified in the ELGs must be

incorporated into the NPDES permit. Therefore, it is critical that permit applicants adequately

characterize their operations and discharges so that it can be determined which ELGs apply. 

Predicting a water balance and maintaining proper water management are critical to ensuring

compliance with the “zero discharge” provisions of certain of the ELGs. Water balance issues

are discussed in more detail in Appendices A and E. As noted throughout this document, early

consultation with EPA is strongly recommended. With the advent of the storm water program

(section 2.4), consultation with EPA to ensure discharges are correctly characterized has become

even more important. 

Figure 2 gives an example of the care with which discharges must be examined and

characterized in order to determine their regulatory classification. As can be seen, both the

source of discharge and the ways in which discharges are managed (segregated versus mixed, for

example) affect the regulatory classification and thus the applicable standards and requirements. 

For discharges or pollutants not covered by the ELGs, EPA uses Best Professional

Judgement (BPJ) to develop technology-based limits. In addition, when technology-based limits

cannot be defined or will not ensure compliance with applicable water quality standards for the

receiving waters, permit writers develop more stringent water quality-based limits (see section

2.3).

Information on implementation of ELGs in permits can be found in the Permit Writers

Manual. More information on the development of ELGs for the ore mining and dressing

industry is found in The Development Document for Effluent Limitations Guidelines and

Standard for the Ore Mining and Dressing Point Source Category (EPA 440/1-82/061).

2.3 Water Quality Standards and Water Quality-Based Permitting

In addition to the technology-based limits discussed in the previous section, EPA evaluates

proposed discharges to determine compliance with Section 301(b)(1)(C) of the CWA. This

section of the Act requires the establishment of limitations in permits necessary to meet water

quality standards. In deciding whether or not water quality-based effluent limits are needed,

EPA first determines whether the discharge would cause, has the reasonable potential to cause,

or would contribute to an excursion of water quality criteria. If a “reasonable potential” exists,

then
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12 January 2003 12

Table 2. Industry Sectors and Types of Applicable Limits 40 CFR Part 440

Industry sectors covered by subparts Types of limits placed on discharges

Subpart (Subcategory):

A Iron ore

B Aluminum ore (bauxite)

C Uranium, Radium, and Vanadium ores

D Mercury ore

E Titanium ore

F Tungsten ore

G Nickel ore

H Vanadium ore (when mined alone)

I Antimony ore--reserved

J Copper, Lead, Zinc, Gold, Silver, and

Molybdenum ores (except gold/silver

placer, which is in subpart M)

K Platinum ores

Subparts A, B, C, D, E, F, G, H, J, K: Numeric limits

on mine drainage.

Subparts A, C, E, F, G, H, J, K: Numeric limits on

process waste water discharges from certain mills

Subparts A, C, D, J: Zero discharge allowed from

certain mills except, if precipitation exceeds

evaporation on annual basis. Such facilities may

discharge the difference (net precipitation) and

discharges must meet mine drainage limits.

Subpart J: Zero discharge allowed from certain mills,

except that discharge may be allowed if

contaminant buildup in recycle water interferes with

ore recovery; this requires operator to make such a

demonstration.

Table 3. Selected Definitions and Provisions in 40 CFR Part 440

Selected Definitions

§440.132

"Active mining area"

"a place where work or other activity related to the extraction, removal, or recovery of metal ore is

being conducted, except with respect to surface mines, any area of land on or in which grading has

been completed to return the earth to desired contour and reclamation work has begun."

"Mine" 

Active mining area, including "all land...used in or resulting from the work of extracting metal ore or

minerals from their natural deposits by any means or methods,..."

Selected Provisions

§440.131(b) and (c) 

Storm exemption for discharge and no discharge facilities in subcategories A,B,C,D,E,F,G-H,J,K:

Facilities designed/constructed/maintained to contain or treat normal process water and 10-year/24-

hour precipitation may qualify for exemption from ELG limits. 10-year/24-hour volume includes runoff

from all active mine areas that is not diverted. Development document provides details on qualifying

for "excursion:"

12 other paragraphs describing meaning of "contain" and "treat" and further explaining the scope of

storm exemption.
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13 January 2003 13

Figure 2. Example of Discharge Classification Depending on Wastewater 

Source and Management
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14 January 2003 14

 water quality-based effluent limits are calculated for that parameter. The permitted effluent

limit for a particular pollutant will be the more stringent of either the technology-based or water

quality-based limit. 

Where there is a “reasonable potential”, EPA also develops water quality-based effluent

limits for whole effluent toxicity (WET). WET is defined as the total toxic effect of an effluent

measured directly with a toxicity test. WET is a useful parameter for assessing and protecting

against impacts upon water quality caused by the aggregate effect of a mixture of pollutants in

the effluent. EPA develops water quality-based effluent limits according to the guidance in

Technical Support Document for Water Quality-Based Toxics Control (EPA 1991; also called

the “TSD”). More general information on water quality-based permitting can be found in the

Permit Writers Manual. Information used to determine the need for and to develop water

quality-based effluent limits includes:

• Applicable receiving water quality standards 

• Characteristics and variability of the effluent

• Characteristics and variability of the receiving water

• Where appropriate, dilution of the effluent in the receiving water (mixing zone)

Because the receiving water quality standards are key to developing water qualitybased effluent limits, a brief discussion of water quality standards and mixing zones is presented

below. Various provisions of water quality standards are also discussed in Appendices B and D.

Water Quality Standards. Under Section 303(c) of the Clean Water Act, States are required to

develop water quality standards to protect public health, enhance the quality of water, and serve

the purposes of the Clean Water Act. EPA’s regulations for State development of water quality

standards are at 40 CFR Part 131. All 50 states have developed water quality standards that EPA

has approved.

EPA has found that correctly identifying applicable water quality standards often poses

significant challenges for mine project proponents. Since many projects will include direct or

indirect discharges to surface waters, knowing the applicable standards is essential to

determining whether a project will adversely affect the environment and whether there is a need

for water quality-based effluent limits. Baseline monitoring programs and evaluation of

potential impacts to surface water should be tailored towards being able to determine whether

standards will be met.

Water quality standards consist of three major components:

• Designated Uses: All water bodies in a State are classified based on expected

designated uses. Typical designated uses include public water supply, recreation, and

propagation of fish and wildlife. Different segments of a water body may have

different uses. This is important because both impact predictions and water qualitybased effluent limits must consider downstream uses.
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15 January 2003 15

• Water Quality Criteria: Section 303 of the Clean Water Act requires states to adopt

criteria sufficient to protect the designated uses for State waters. These criteria may be

numeric or narrative. Numeric water quality criteria are typically expressed as levels,

constituent concentrations, or toxicity units. Narrative criteria are statements that

describe water quality goals, e.g., “free of objectionable color, taste, or odor” or “free

from toxics in toxic amounts.” EPA requires States to develop mechanisms to

implement narrative criteria. For water bodies with multiple designated uses, multiple

criteria also apply. The most stringent of the applicable criteria is used to develop

water quality-based effluent limits.

Of note for mining sites is that water quality criteria for some metals are hardness

dependent. Also, some state water quality criteria for metals are presented in different

forms (total, total recoverable, or dissolved). However, NPDES regulations require

that permit limits be expressed as total recoverable. Where the criteria are different,

EPA uses default translators to translate between total and dissolved. EPA uses

default translators unless the permittee develops approvable site-specific translators

(see Appendix B).

• Anti-degradation: Each State must adopt an anti-degradation policy. State policies

must incorporate three components. First, existing uses must be maintained and

protected. Second, where water quality is higher than necessary to protect designated

uses, that quality must be maintained and protected unless degradation is shown to be

necessary for social and economic reasons and other alternatives are not available. 

Third, waters that are designated as Outstanding Resource Waters may not be

degraded. In states that have approved NPDES permit programs the states will

incorporate compliance with their anti-degradation policy as a part of the permitting

process. For states without an approved NPDES program, where EPA will be issuing

the permit, EPA will require the affected state to determine compliance with the state's

anti-degradation policy and provide EPA with certification of compliance. Applicants

should consult with the appropriate state agency and be prepared to demonstrate that

the proposed project will comply with the state's anti-degradation policy.

Mine operators should initially obtain the applicable State water quality standards and

regulations. These can be obtained directly from State agencies. Most are also now available

from State government websites on the Internet. Each State must review its water quality

standards every three years, although more frequent changes to standards and regulations are

common. Operators must obtain the most recent standards and remain up-to-date on changes

throughout the permitting process. This further emphasizes the need for frequent communication

with State agency personnel to anticipate potential standard modifications that could affect

project planning and evaluation.

Mixing Zones. Mixing zones allow for concentrations of pollutants to exceed water quality

criteria in small areas immediately around discharge points prior to full mixing of effluent and

the receiving waters. Under the Clean Water Act, States have the authority to determine whether

they will allow mixing zones and under what conditions. As such, each State has different

mixing zone provisions. The sizes of mixing zones are often determined based on low flow
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16 January 2003 16

stream conditions, i.e., when the least dilution is available in the receiving water. In addition,

available dilution is dependent on background constituent concentrations. A discharger must

apply to the appropriate state agency for a mixing zone and the state must certify the mixing

zone for EPA to use it in developing permit limitations. A mass balance, modeling, or other

mixing zone assessment is generally required to support a mixing zone application. In addition,

some states may require a biological assessment to support the mixing zone. EPA consults with

states early on in the NEPA process, and NEPA documents generally display effluent criteria

based on various dilution scenarios. EPA also generally sends preliminary draft permits to states

for pre-certification. Mixing zones are discussed in more detail in Appendix B. 

Site-specific Criteria and Reclassification. States typically have provisions for establishing sitespecific criteria for individual constituents in a specific water body. Such criteria often allow for

higher constituent concentrations than state-wide criteria because the individual water body can

be demonstrated to achieve designated uses at the higher levels. Mine operators who elect to

pursue site-specific criteria will be required to provide extensive chemical and biological testing

for the water body. They need to work closely with State agencies in developing any requests

for site-specific criteria. In addition, EPA needs to be consulted because site-specific criteria

require EPA approval since they represent changes to the State water quality standards. 

Modifications to state standards also require public involvement.

If a water body is not being used for a designated use, mine operators can pursue reclassification. The criteria under which a designated use may be removed are generally defined

at 40 CFR Part 131.10(g). Requests for re-classification are also complex and require close

coordination with State agencies and EPA. In addition, 40 CFR Part 131.10(h) specifies where

designated uses cannot be removed. Specifically, designated uses cannot be removed if they are

existing uses, unless more protective uses are applied.

Total Maximum Daily Load (TMDL). Section 303(d) of the CWA requires States to identify

water bodies that are not meeting their assigned designated uses (e.g., water bodies that exceed

the water quality criteria). Section 303(d) also requires states to develop TMDLs (total

maximum daily loads) for these water quality-limited water bodies. A TMDL is a determination

of the amount of a pollutant, or property of a pollutant, from point, nonpoint, and natural

background sources, including a margin of safety, that may be discharged to a water-limited

water body. The TMDL defines waste load allocations for point sources that discharge to the

water body. These waste load allocations are developed into permit limits. New mine

proponents should ascertain whether surface waters in the project vicinity have been included on

the 303(d) list and, if that is the case, the reasons for not attainting the water body’s designated

uses. If there are listed water bodies, coordination with EPA and State agencies is essential to

determine the status of any TMDLs and how the listing could affect NPDES permit

requirements.

2.4 Storm Water
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17 January 2003 17

In addition to the development of effluent limits and conditions for discharges of

wastewater, the NPDES Program also includes provisions for control of storm water discharges. 

As indicated in section 2.1, storm water associated with industrial activity includes any

discharges from conveyances directly related to manufacturing, processing or raw materials

storage areas at industrial facilities. On August 7, 1998, EPA published in the Federal Register

a further clarification of the applicability of the effluent guideline requirements for mine

drainage and the applicability of EPA’s storm water regulations to runoff from waste rock and

overburden piles (63 FR 42533-42548). Figure 2 illustrates how discharge from a waste rock

pile may be classified as either wastewater (i.e., mine drainage) or storm water. In summary, 

EPA’s storm water regulations generally apply to most storm water discharges from active and

inactive mine sites where the storm water discharges are not commingled with process/mill water

or mine drainage.

Storm water associated with industrial activity at mine sites may be permitted in two ways,

either by an individual facility-specific NPDES permit or by a general permit. Facilities may be

required to or may request to be covered under an individual permit. For example, the facility

may wish to consolidate the control of both process water and storm water discharges under a

single comprehensive individual NPDES permit. In other cases, EPA or a delegated state may

require an individual permit to address facility-specific conditions (e.g., the necessity for water

quality-based limits for discharges to streams in certain cases.)

Unlike discharges of process wastewater where numerical effluent limits (technologybased and/or water quality-based) are used to control the discharge of pollutants, the primary

permit condition used to address discharges of pollutants in a facility’s storm water is a sitespecific pollution prevention plan or best management practices (BMP) plan. All individual

permits for storm water discharges issued by EPA will include a requirement to develop a BMP

plan. BMPs are defined in 40 CFR 122.2 as “... schedules of activities, prohibitions of practices,

maintenance procedures, and other management practices to prevent or reduce pollution of

‘waters of the United States.’ BMPs also include treatment requirements, operating procedures,

and practices to control plant site runoff, spillage or leaks, sludge or waste disposal or drainage

from raw material storage.” See Appendix E and H for more information on development of a

BMP Plan. Beyond the BMP plan, permits may include other requirements (such as monitoring)

based on the Best Professional Judgment (BPJ) of the permit writer and as necessary to ensure

compliance with water quality standards.

EPA has determined that certain categories of discharges, including many categories of

storm water discharges, are more appropriately controlled by a “general” permit rather than by

individual permits for each discharge. General permits are issued under the provisions of 40

CFR 122.28 and contain eligibility requirements as well as the specific requirements that

applicants must follow in order to have their discharges authorized under the permit. A mining

facility may elect to have any storm water discharges authorized under an EPA or State NPDES

permitting authority-issued general permit (depending on the mine’s location). Mining sites

within EPA’s jurisdiction may seek permit coverage under the Multi-Sector General Permit for

Storm Water Discharges Associated with Industrial Activities, following the sector-specific

requirements for Mining Activities. This EPA permit is commonly referred to as the MSGP, and

the most recent version issued by EPA is referred to as the MSGP-2000. The sections of the
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18 January 2003 18

MSGP-2000 applicable to hardrock mining facilities primarily include requirements for a sitespecific Storm Water Pollution Prevention Plan (SWPPP) which incorporates BMPs and

applicable monitoring provisions. As required by the August 7, 1998 Federal Register, storm

water discharges from waste rock and overburden must be more extensively tested prior to 

submitting an application as well as during the permit term (i.e., during years two and four of

the five-year permit coverage). This includes sampling and analysis for metals. 

EPA’s MSGP includes three types of monitoring: analytical or chemical monitoring,

compliance monitoring for effluent guidelines compliance, and visual examinations for storm

water discharges. The analytical monitoring requirements contained in the MSGP include

“benchmarks,” that is, pollutant concentrations which EPA has determined represent a level of

concern. The level of concern is a concentration at which a storm water discharge could

potentially impair, or contribute to impairing water quality or affect human health from ingestion

of water or fish. The benchmarks are also viewed by EPA as a level that, if below, a facility

presents little potential for water quality concern. As such, the benchmarks also provide an

appropriate level to determine whether a facility’s storm water pollution prevention measures are

being successfully implemented. The benchmarks are not effluent limitations and should not be

interpreted or adopted as such. These values are merely levels which EPA has used to determine

if a storm water discharge from any given facility merits further monitoring to ensure that the

facility has been successful in implementing a SWPPP. For more detail on the monitoring

requirements for hardrock mining facilities, refer to Part 6.G of the MSGP-2000, and the EPA

discussion of the monitoring requirements for industrial storm water discharges published in the

Federal Register (65 FR 64766 - 64773, October 30, 2000). 

In areas where EPA is the permitting authority (e.g., Idaho and Alaska), the MSGP

authorizes storm water discharges from the actual ore processing operation at the mine site. In

contrast, any clearing, grading and excavation activities conducted as part of the exploration and

construction phase of a mining operation must be permitted under the most recent issuance of the

EPA Construction General Permit if the area disturbed is one or more acres, because discharges

from such areas are best managed under the construction-related BMPs and requirements

contained in the Construction General Permit. Exploration/construction operations of less than

one acre can be covered by the Multi-Sector General Permit. See Part 6.G.5 of the MSGP and

the most current EPA-issued Construction General Permit for further details.

 Most general permits contain eligibility restrictions—that is, the permit prohibits certain

discharges from coverage (see Part 1.2 of the EPA-issued MSGP-2000 for further details). 

EPA (and authorized states) also have the discretion to deny general permit coverage to any

discharge and require an individual permit. Therefore, the Agency recommends that mine

operators coordinate with EPA or their state NPDES permitting authority prior to submitting an

application or request for permit coverage.
EPA and Hardrock Mining: A Source Book for Industry in the Northwest and Alaska

2

 Forms also are available via the Internet at http://www.epa.gov/owm/npdes.htm or

http://www.epa.gov/owm/swlib.htm. 

19 January 2003 19

2.5 Information Needs for NPDES Permitting

In order to issue an NPDES permit, EPA and authorized States need extensive information

about the proposed facility and the anticipated discharges. Application and information

requirements are specified in the following sections of the regulations:

• 40 CFR 122.21(f): Information requirements for all applicants. 

• 40 CFR 122.21(g): Application requirements for all existing dischargers.

• 40 CFR 122.21(h): Application requirements for facilities that discharge only nonprocess wastewater.

• 40 CFR 122.21(k): Application requirements for new sources and new discharges. 

• 40 CFR 122.26(c): Application requirements for facilities that discharge storm water

associated with industrial activity.

Table 4 identifies the various forms that these sections require to be submitted and the

types of information required by each. Copies of the forms may be obtained from EPA and

authorized states2.

Table 4. EPA Forms Required for NPDES Application

Form number Applicant Information type

EPA 3510-1 (Form 1) All new permits and renewals Basic information on the facility, location,

owner, etc. 

EPA 3510-2C (Form 2C) Existing dischargers Detailed information on discharge

sources, locations, volumes, sources,

treatment, characterization.

EPA 3510-2D (Form 2D) New sources and discharges Similar to Form 2C, but some data may

have to be estimated.

EPA 3510-2E (Form 2E) Discharges of non-process

wastewater

Information on discharge, chemistry,

treatment, etc

EPA 3510-2F (Form 2F) Storm water associated with

industrial activity (individual

permit)

Detailed information on storm water

sources and characteristics.

EPA 3510-6 Storm water associated with

industrial activity (general

permit)

Notice of Intent for discharge(s) to be

covered under multi-sector general permit

(see section 2.4) 
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20 January 2003 20

Table 5 provides an overview of the types of information generally needed to develop an

NPDES permit. The table references the Source Book appendices where additional details

regarding information needs may be found. The magnitude and extent of the information needs

described in Table 5 may depend on site-specific factors. Permit applicants should consult with

EPA and the certifying State agency early in the planning process to ensure that appropriate data

is collected. This is particularly the case where the permittee applies for a mixing zone, elects to

develop translators or site-specific criteria, or where threatened or endangered species may be

present.

Table 5. Overview of Information Needs for NPDES Permitting

Information Type Data Needs Source Book Appendix

Description of wastewater

management and water balance

Outfall locations and topographic

map

n/a

Identification of sources of pollutants

and sources of wastewater

Appendix E and F

Hydrologic characterization, water

balance

Appendix A

Description of wastewater treatment Appendix E

Effluent characteristics and

variability

Flow, chemical, physical and WET

characterization

Appendix D

Receiving water characteristics

and variability

Flow, chemical, physical, and

biological characterization

Appendix B

Storm water characterization Topographic map 

Flow, chemical analysis, physical

analysis

Appendix D

Description of BMPs Appendix E

Determination of available

dilution

Mixing zone assessment, modeling Appendix B

Site-specific assessments Aquatic resources characterization Appendix G

Development of translators Appendix B

Development of site-specific criteria Appendix B

3.0 DISCHARGE OF DREDGED OR FILL MATERIAL TO WATERS OF THE U.S. (SECTION 404)

Section 404 of the Clean Water Act addresses the placement of dredged or fill material into

waters of the U.S. and has become the principal tool in the preservation of wetland ecosystems. 

Wetlands subject to regulation under Section 404 are those areas that meet the criteria defined in

the 1987 Corps of Engineers’ Wetland Delineation Manual. Section 404 regulatory authority is

shared between the EPA and the Corps of Engineers (COE or Corps). Section 404(a) establishes
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21 January 2003 21

the authority for the COE to issue permits for discharges of dredged or fill materials into “waters

of the U.S.” at specified disposal sites. Permitted disposal sites must comply with EPA’s 

§404(b)(1) guidelines. In addition, §404(c) gives EPA “veto” authority to prevent or reverse

COE permit issuance at specified disposal sites. In practice, EPA only exercises its veto power

in rare instances where the proposed disposal site is of significant resource value, and where

EPA and the COE cannot resolve disputes through the normal public notice review process.

Section 404(e) establishes that the Corps may issue general permits on a State, regional, or

National basis for categories of activities that the Secretary of the Army deems similar in nature,

cause only minimal adverse environmental effects, and have only a minimal cumulative adverse

effect on the environment. General permits may be issued following public notice and a period

for public comment; the permits must be based on the §404(b)(1) guidelines and establish

conditions that apply to the authorized activity. Exceptions to §404 requirements are established

in §404(f) and conditionally include the construction of temporary roads for moving mining

equipment. Applicants are strongly encouraged to check with the local COE District office

regarding general permits and special conditions that may be in effect in the area in which they

propose to mine. Often there are state-specific conditions imposed, particularly with respect to

Nationwide Permits. 

The process of issuing an individual §404 permit begins with a permit application. The

application typically contains information describing the project, project area, and project

purpose; wetlands and other “waters of the U.S.” that could potentially be directly or indirectly

impacted; and mitigation, monitoring and maintenance plans. The §404(b)(1) Guidelines

require the proponent to demonstrate that the selected project alternative is the least

environmentally damaging practicable alternative. It is important to note that the preferred

alternative selected during the NEPA analysis may not be the least environmentally damaging

practicable alternative. In addition, it should be noted that an alternative does not necessarily

have to involve only land currently owned or controlled by the proponent. It can involve actions

(mitigation, for example) on land that could be easily obtained by the proponent.

It is thus important to avoid and/or minimize all impacts to wetlands and other waters of

the U.S. to the fullest extent possible. For proposed fill in ‘special aquatic sites’, which include

wetlands, there is a rebuttable presumption against the need to fill for non-water dependent

activities. A Memorandum of Agreement (MOA) between the COE and EPA, dated February 6,

1990, establishes the policy and procedure in determining the type and level of mitigation

necessary to comply with the §404(b)(1) Guidelines. The MOA sets ‘no net loss’ of wetland

functions and values as a national goal and defines the types of mitigation, for practical

purposes, as minimization and compensatory. Although compensatory mitigation is often the

focus of project proponents, from a regulatory perspective, avoidance and minimization should

be the focus of any project with the potential to impact wetlands and other waters of the United

States. A project description submitted as part of an environmental impact assessment or permit

application should clearly demonstrate how avoidance and minimization have been addressed. 

The COE evaluates the application based on requirements of the CWA, including the

§404(b)(1) guidelines, and based on comments received from public notice reviewers, which

typically includes EPA. Since the issuance of §404 permits are subject to NEPA review, the
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22 January 2003 22

COE then prepares an environmental assessment or, in some cases, an EIS (or contributes to

another agency’s EIS as a cooperating agency) and issues a statement of finding. A permit is

then issued or denied based on the finding. EPA may exercise its veto authority (§404(c)) at

anytime during the permit application process, or even prior to a permit application being filed. 

It should be noted that the §404(b)(1) guidelines limit issuance of §404 permits for non-water

dependent projects (including mines) to the “least environmentally damaging practicable

alternative.” The term “practicable” is defined [40 CFR230.3(q)] as “available and capable of

being done after taking into consideration cost, existing technology and logistics in light of

overall project purposes.” 

As was recommended above for NPDES permit applications, it is highly advisable for

applicants for §404 permits to consult with the Corps of Engineers and other appropriate

regulatory and resource agencies prior to submission of the application. This facilitates a mutual

understanding of the resource issues of concern and can enable early identification of

alternatives that avoid and/or minimize impacts and allows for early input on mitigation

requirements and design. This early consultation can significantly reduce the time that might

otherwise be necessary. If the proposed project involves siting a tailings impoundment where

there are or may be wetlands or other waters of the U.S., applicants should consult with both the

Corps and EPA regarding procedures for authorization to site a non-jurisdictional waste

treatment system in waters of the U.S. Also, in May 2002 EPA and the Corps promulgated a

final rule [Federal Register: May 9, 2002 (Volume 67, Number 90)] regarding the definition of

fill material that includes certain mining wastes that are not subject to NPDES effluent

guidelines (e.g., waste rock). Applicants are strongly encouraged to consult with the Corps and

EPA regarding the proper regulatory tool (404 permit vs. NPDES permit) for authorizing the

placement of such material in wetlands or other waters of the U.S.

The Corps has released a number of Regulatory Guidance Letters that were most recently

published in the Federal Register on March 22, 1999 (61 FR 13783-13788). These can be

accessed through the COE website at http://www.usace.army.mil, which also includes extensive

information on COE regulatory programs. Appendix I - Wetlands contains information related

to wetlands terminology, characterization, and impact assessment.

Enforcement authority is divided between the Corps and EPA: the Corps provides

enforcement action for operations discharging in violation of an approved permit while EPA has

primary authority over any operation discharging dredged or fill materials without a §404 permit. 

4.0 THE NATIONAL ENVIRONMENTAL POLICY ACT

The National Environmental Policy Act (NEPA) of 1969 became law on January 1, 1970

(Pub. L. 91-190, 42 U.S.C. 4321 et seq.). NEPA serves as the basic national charter for

environmental protection. The law requires every federal agency to analyze and describe

potential environmental effects that could arise from any action or legislation proposed by that

agency. NEPA provides for public participation through public notices of intent, the solicitation

of public comment, and as appropriate, public hearings. A key element of public participation is

scoping, at which time the public can identify the key issues of concern.
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The general framework for implementing NEPA requirements is presented in regulations

issued by the Council on Environmental Quality (CEQ) which may be found at 40 CFR Parts

1500-1508. In general, the analysis and identification of the impacts of proposed federal

actions, and alternatives to those actions, are presented in environmental assessments (EAs)

and/or, for “major federal actions significantly affecting the quality of the human environment,”

in Environmental Impact Statements (EISs). Each of these terms is defined in CEQ’s regulations

(40 CFR Part 1508). Over the past 25 years, the NEPA framework for environmental review of

proposed Federal actions has been substantially refined, based on further congressional

directives, action by CEQ, and an extensive body of case law. 

Each federal agency has developed its own rules for NEPA compliance that are consistent

with the CEQ regulations but address its own specific missions and program activities. EPA’s

NEPA regulations can be found at 40 CFR Part 6. 

4.1 EPA’s NEPA Role

Under NEPA, EPA can serve as a lead agency, cooperating agency, or reviewing agency.

Most EPA decisions and actions are not subject to NEPA, or the decision making process that

leads to proposed EPA actions has been determined to be functionally equivalent to that required

by NEPA. The major exception to this in the case of mining is the issuance by EPA of NPDES

permits subject to new source performance standards (see section 4.2). The decision whether to

issue such a permit is subject to NEPA, and thus the potential environmental impacts of permit

issuance must be analyzed and documented in an EA and/or EIS. Where an EIS is required,

EPA is either the lead or, more commonly, a cooperating agency in preparing the EIS. EPA

recognizes that many other federal, state, and local authorities have jurisdiction over various

components of a mine’s location, construction, operation, and closure. Regardless of EPA’s role

under NEPA, EPA tries to work collaboratively with other involved agencies.

Lead Agency. In some instances, delineated at 40 CFR 1501.5, more than one agency’s action

is subject to NEPA. In such cases, one of the agencies becomes the lead agency (or there are colead agencies). When an EPA action is subject to NEPA, EPA generally serves as the lead

agency for proposed projects that do not involve federal lands but that include actions over

which EPA has jurisdiction by law. For example, EPA would likely be the lead agency under

NEPA for a proposed project on private lands that requires a new source NPDES permit in a

State where EPA is the NPDES permitting authority (see 40 CFR, Part 6, Subpart F). EPA can

also serve as a lead agency when tribal lands and public lands are involved and where EPA’s

permitting authority is broader in scope than another agency’s. In addition, EPA is responsible

for NEPA review to support proposed legislation that significantly affects environmental quality

as outlined in 40 CFR 6.102(b). As described in 40 CFR 6.604(g), EPA may prepare NEPA

documentation using agency staff, by contracting with a consulting firm, or by using a ‘third

party agreement’ between the applicant, EPA, and a contracting firm. The ‘third party’ approach

is most often used for large mine projects where EPA is the lead agency. Under this approach,

the EPA is responsible for directing the contracting firm while the applicant pays the costs. The

responsibilities of lead agencies are outlined in 40 CFR § 1501.5. 
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Cooperating Agency. Federal agencies that have jurisdiction by law, but that are not lead

agencies, may be cooperating agencies upon request by the lead agency (40 CFR 1501.6). As a

cooperating agency, EPA participates in the scoping process and, upon request of the lead

agency, may assume responsibilities for developing information and preparing portions of NEPA

documents pertaining to the agency’s areas of expertise. For example, EPA generally serves as a

cooperating agency whenever a mine that is proposed on National Forest Service or Bureau of

Land Management land requires an EPA NPDES permit. Depending on the types of expertise

available to the Forest Service, EPA may play a significant role in efforts to predict effluent

quality and evaluate potential water quality impacts.

Reviewing Agency. Under Section 309 of the Clean Air Act, EPA is required to review and

comment in writing on all major Federal actions. The Agency reviews and prepares written

comment on every draft EIS prepared by other agencies, and assigns a rating to the

environmental impact of the proposed action and to the adequacy of the draft EIS (see section

4.3). The comments are available to the public, and the ratings and a synopsis of the comments

are published in the Federal Register. When EPA has serious concerns about the impacts of the

proposal or the adequacy of the EIS, the Agency consults with the lead agency. EPA also

reviews final EISs, particularly ones where significant issues were raised in earlier comments. 

EPA comments on final EISs, but not its ratings, are made available to the public and a synopsis

of comments is published in the Federal Register. 

If EPA’s review of a final EIS determines that a proposed action is or remains

“unsatisfactory from the standpoint of public health or welfare or environmental quality," EPA

may refer the matter to the Council on Environmental Quality in accordance with 40 CFR Part

1504. 

4.2 EPA Requirements for Environmental Review Under NEPA and the CWA

40 CFR Part 6 outlines EPA’s policies and processes for identifying and analyzing the

environmental impacts of EPA-related activities and for preparing and processing EISs. Subpart

A of the Procedures provides an overview of the Agency’s purpose and policy, institutional

responsibilities, and general procedures for conducting reviews. Subpart A outlines EPA’s basic

hierarchy of NEPA compliance documentation as follows:

• Environmental Information Document (EID): a document prepared by applicants,

grantees, or permittees and submitted to EPA. This document should be sufficient in

scope to enable EPA to prepare an environmental assessment. 

• Environmental Assessment (EA): a concise document prepared by EPA, or by a

contractor under EPA’s direction, that provides sufficient data and analysis to

determine whether an EIS or finding of no significant impact is warranted.

• Notice of Intent (NOI): announces the Agency’s intent to prepare an EIS. The NOI,

which is published in the Federal Register, reflects the Agency’s finding that the

proposed action may result in “significant” adverse environmental impacts on the

human environment.
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• Environmental Impact Statement (EIS): a formal and detailed analysis of

alternatives including the proposed action, undertaken according to CEQ

requirements and EPA procedures. Guidelines that describe the focus and intent of

EISs are provided in 40 CFR 1502.2. EISs must provide rigorous, unbiased analyses

of potential impacts from the proposed action and its alternatives, determine whether

unavoidable adverse environmental impacts would occur, and describe any irreversible

and irretrievable commitments of resources. The treatment of environmental impact,

which generally receives close scrutiny, must consider connected actions, cumulative

actions, and similar actions (40 CFR 1508.25).

• Finding of No Significant Impact (FNSI): a concise document that presents EPA’s

finding that the action analyzed in an EA (either as proposed or with alterations or

mitigating measures) will not result in significant impacts. The FNSI is made

available for public review, and is typically attached to the EA and included in the

administrative record for the proposed action. 

• Record of Decision (ROD): a statement published in the Federal Register that

describes the course of action to be taken by an Agency following the completion of

an EIS. The ROD typically includes a description of those mitigating measures that

will be taken to make the selected alternative environmentally acceptable. 

• Monitoring: EPA is responsible for assuring that decisions on any action where a

final EIS is prepared are properly implemented.

Subpart B of EPA’s Procedures provides a detailed discussion of the contents of EISs. 

This subpart specifies the format and contents of an executive summary, the body of the EIS,

material incorporated by reference and a list of preparers.

Subpart C of the Procedures describes requirements related to coordination and other

environmental review and consultation requirements. NEPA compliance involves addressing a

number of particular issues, including: (1) landmarks, historical, and archaeological sites; (2)

wetlands, floodplains, important farmlands, coastal zones, wild and scenic rivers, fish and

wildlife, and endangered species; and (3) air quality. Formal consultation with other agencies

may be required, particularly in the case of potential impacts to threatened and endangered

species and potential impacts on historic or archaeological resources. Section 5.2 discusses the 

Endangered Species Act consultation process.

Subpart D of the Procedures presents requirements related to public and other Federal

agency involvement. NEPA includes a strong emphasis on public involvement in the review

process. Requirements are very specific with regard to public notification, convening of public

meetings and hearings, and filing of key documents prepared as part of the review process.

Subpart F presents environmental review procedures for the New Source NPDES Program. 

This Subpart specifies that the requirements summarized above (Subparts A through D) apply

when two basic conditions are met: (1) the proposed permittee is determined to be a new source
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under NPDES permit regulations (see Section 2.1); and (2) the permit would be issued within a

State where EPA is the permitting authority (i.e., that State does not have an approved NPDES

program in accordance with section 402(b) of the CWA. In EPA Region 10, Alaska and Idaho

do not have approved NPDES programs). This Subpart also states that the processing and

review of an applicant’s NPDES permit application must proceed concurrently with

environmental review under NEPA. Procedures for the environmental review process are

outlined. Subpart F also provides criteria for determining when EISs must be prepared, as well

as rules relating to the preparation of RODs and monitoring of compliance with provisions

incorporated within the NPDES permit. Additional information that is not relevant to the

New Source process can be found in Subparts E, G, H, I, and J of the Procedures. 

Of particular importance to new source NPDES permit applicants is preparing the

Environmental Information Document (EID). It is highly recommended that applicants confer

with EPA regarding the scope of the EID as a well prepared EID will make the ensuing NEPA

process run much more smoothly. In general, an EID should address the following (adapted

from EPA Region 6, EID Handbook, 1995):

• An effective description of the project, with an emphasis on project features which

cause environmental changes, and with alternatives to those features.

• A concise description of the environmental setting where the project takes place,

with an emphasis on resources which are highly valued, very sensitive to change

and/or certain to be affected by the project.

• Evidence that the project has been designed and located, and will be built and

operated, to reasonably minimize adverse environmental changes and to improve

environmental benefits. 

• The applicant’s own assessment of environmental impacts or changes.

• Discussion of cumulative environmental effects which would result from interaction

with other activities in the same watershed, same airshed or same economic region.

• Documentation that necessary coordination regarding special resources has taken

place with certain Federal and state agencies (e.g., Corps of Engineers, U.S. Fish and

Wildlife Service, State Historic Preservation Officer).

Section 6 of this Source Book provides guidance on information needs related to NEPA

analyses. 

4.3 When is an EIS Required?

The determination of whether or not an EIS is required is important as it impacts the nature

and extent of data that needs to be collected and analyses that need to be performed to determine

the environmental impacts of a proposed project (and project alternatives). NEPA requires that

an EIS be prepared for “major” Federal actions “significantly affecting the quality of the human
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27 January 2003 27

environment.” Generally, the determination of the need for an EIS hinges on finding that the

proposed action would result in significant adverse impacts.

EPA’s procedures provide general guidelines and specific criteria for making this

determination (40 CFR 6.605). General guidelines are (40 CFR 6.605(a)):

• EPA shall consider both short- and long-term effects, direct and indirect effects, and

beneficial and adverse environmental impacts as defined in 40 CFR § 1508.8. 

• If EPA is proposing to issue a number of new source NPDES permits within a limited

time span and in the same general geographic area, EPA must consider preparing a

programmatic EIS. In this case, the broad cumulative impacts of the proposals would

be addressed in an initial comprehensive document, while other EISs or EAs would be

prepared to address issues associated with site-specific proposed actions. 

EPA’s specific criteria for preparing EISs for proposed new source NPDES permits are

found in 40 CFR 6.605(b):

• The new source will induce or accelerate significant changes in industrial,

commercial, agricultural, or residential land use concentrations or distributions, which

have the potential for significant effects. Factors that should influence this

determination include the nature and extent of vacant land subject to increased

development pressure as a result of the new source, increases in population that may

be induced, the nature of land use controls in the area, and changes in the availability

or demand for energy. 

• The new source will directly, or through induced development, have significant

adverse effects on local air quality, noise levels, floodplains, surface water or ground

water quality or quantity, or fish and wildlife and their habitats. 

• Any part of the new source will have significant adverse effect on the habitat of

threatened and endangered species listed either Federally or by the State. 

• The issuance of the new source permit would result in a significant direct adverse

impact on a property listed or eligible for listing in the National Register of Historic

Places. 

• The issuance of the new source permit would result in significant adverse efforts on

parklands, wetlands, wild and scenic rivers, reservoirs or other important water bodies,

navigation projects, or agricultural lands. 

The determination of significance can be challenging. CEQ provides some guidance in the

form of a two-step conceptual framework which involves considering the context for a proposed

action and its intensity (40 CFR 1508.27). Context can be considered at several levels, including
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28 January 2003 28

the region, affected interests, and the locality. Intensity “refers to the severity of the impact.” 

CEQ lists a number of factors to be considered when judging severity, including: 

• Effects on public health and safety

• Unique characteristics of the geographic area

• The degree to which effects are likely to be controversial

• The degree to which effects are uncertain or involve unique or uncertain risks

• Cumulative effect of the action

• Whether the action would threaten a violation of Federal, State, or local law or

regulation

The nature of the mining industry can make it particularly difficult to assess significance. 

Potential impacts are often uncertain, they often are delayed in time from the permitting action,

and they can be quite controversial. In addition, impacts may occur in environments previously

degraded by mining or other activities, or environments where naturally occurring pollutants

contribute to environmental degradation. It is also important to note that impacts may be both

beneficial and adverse. There may be a significant effect even if, on balance, the effect will be

beneficial.

In general, it is essential for applicants to coordinate with EPA early in the planning

process to determine the data needed in order for EPA to prepare an EIS. Section 6 describes the

general information needed for EISs on new mining proposals.

5.0 OTHER AUTHORITIES

5.1 Clean Air Act

Clean Air Act (CAA) provisions apply to a wide range of emissions sources from mine

sites, including stack/point sources and fugitive sources. Fugitive emissions are generally

defined as sources that are not easily controlled (e.g., conveyors can be controlled while open

piles cannot). CAA requirements are generally applied through several different types of

programs. These requirements can be described by three categories: (1) new source permits,

including prevention of significant deterioration (PSD) and non-attainment permits, (2) new

source performance standards (NSPSs), and (3) State Implementation Plan (SIPs) requirements

for non-attainment areas. Title V of the 1990 CAA Amendments provides for consolidation of

different CAA requirements into single facility permits. EPA's permitting authority is generally

limited to "major" sources. States generally have exclusive permitting authority under CAA

Section 110A(2)c for minor sources. Beyond permitting, EPA must evaluate compliance with

applicable air quality requirements for all new or modified sources associated with proposed

actions that are subject to NEPA.
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29 January 2003 29

Where an operator proposes a new point source or modifications to an existing point

source, the entire facility must be reviewed for air quality impacts. Separate requirements apply

to major and minor sources. Major source determinations are based on the emissions of six

parameters from point sources, including: NOx, SO2, CO, VOCs, particulates, and lead. Most

facilities are major sources if they emit more than 250 tons per year of any of these pollutants. 

Comparison of source emissions with these threshold values includes expected reductions to be

provided by proposed control measures. Mines with complex oxidation processes or smelters

generally trigger at least one of the threshold values for the six parameters and are typically

sources subject to the PSD program.

There are two categories of new source reviews/permits: PSD analyses/permits for

facilities in attainment areas, and non-attainment analyses/permits for facilities located in nonattainment areas. Non-attainment is measured through compliance with the National Ambient

Air Quality Standards (NAAQS) for the six pollutants. A facility in a non-attainment area may

undergo a combination of both PSD and non-attainment analyses: PSD for pollutants that are

achieving ambient air quality standards and non-attainment analyses for specific pollutants that

are causing the non-attainment designation.

PSD requirements include the use of Best Available Control Technology (BACT) for all

emissions sources, stack/point source emissions and fugitives. In addition, total emissions from

a site must not cause exceedances of NAAQS. EPA ensures compliance with NAAQS through

pollutant "increments." The applicable increments for a site depend on facility location. There

are nationwide increments for "Class I" and "Class II" areas. Class I areas lie within 50

kilometers of federally protected lands such as National Parks. More stringent increments may

be established on an airshed-specific basis depending on background air quality and number and

types of sources. In general, facilities that only affect Class II areas do not present issues related

to BACT not meeting the increments. However, facilities located within or that can affect Class

I areas often present difficulties, because the national Class I increments are very stringent and

individual areas can establish even more stringent air quality related values (AQRVs). Modeling

is used under PSD to determine compliance with Class I and II increments. 

5.1.1 New Source Performance Standards

As noted above, the PSD and minor source programs address facility-wide air emissions. 

Under CAA Sections 111/112, EPA has also established minimum national new source

performance standards (NSPSs) for emissions of certain pollutants discharged from specific

types of industrial units and operations. This includes metallic mineral processing (40 CFR Part

60 Subpart LL) and non-metallic mineral processing (40 CFR Part 60 Subpart 670). Mineral

processing is generally defined as extraction and beneficiation operations associated with

transport and beneficiation of ore, including conveyor belt transfer points, screens, crushers,

storage bins, thermal dryers, and truck and railroad loading and unloading. Underground

operations are excluded. The NSPSs include opacity and particulate matter limits from each

point source. In addition, there is an opacity standard for particulate matter that escapes from

containment systems.
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5.1.2 Specific Sources

Table 6 summarizes the applicability of specific Clean Air Act programs to individual

sources at mining operations, generally in the context of whether emissions are fugitive or stack

emissions, and mobile or stationary sources.

Table 6. Potential Emission Sources at Mine Sites

Source Applicability/Authorities

Overburden, Waste

Rock, Tailings, and

Spent Ore 

Fugitive and mobile sources (vehicles); except for Hazardous Air Pollutants

(HAPs), EPA has limited authority to control fugitives unless there is a major

point source; for major new sources, can require BACT, LAERs, and other

controls needed to comply with PSD/non-attainment requirements; emissions

from uranium mill tailings, asbestos mine wastes, and phosphate rock

(radionuclides) specifically covered by National Emission Standards for

Hazardous Air Pollutants (NESHAPs).

Land Application Wet process, little or no CAA applicability

Waste Materials 

Re-use

Primary CAA applicability is NESHAP)requirements for asbestos and

radionuclides emissions related to re-use of waste materials containing

asbestos; phosphate rock containing radionuclides; etc.

Chemical Storage For wet storage, little or no CAA applicability; for dry, considered fugitives as

discussed under waste rock, tailings, and spent ore above

Ore Handling and

Piles

Open piles - fugitives; Covered storage piles/areas and conveyors - point

sources; conveyor transfer points, covered storage areas, truck and railroad

unloading areas covered by NSPS (opacity and particulates)

Heap and Dump

Leaches

Mostly wet and not relevant; where dry, fugitives

Process Ponds Wet - little or no applicability

Mine Pit Major source of fugitive and vehicle emissions, new technology-based

standards for off-road vehicles to be established under Title II; two current

interpretations for vehicles - (1) national - subject to stationary source

permitting as point source, EPA authority largely dependant on major/minor

determination, and (2) Region X - mobile source, exempted from permitting,

but considered by EPA under NEPA.

Underground

Workings

EPA policy decision that all vents from underground mines are stationary

sources and must be evaluated under NEPA and CAA; permitted as point

sources; uncertain how widely applied

Blasting Above ground - fugitives, underground - see underground workings

Vehicle Use See mine pits above, haul roads also major sources of fugitives

Construction Exempted from permitting as temporary activity; SIPs typically have generally

applicable requirements (e.g., must not cause nuisance)
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Table 6. Potential Emission Sources at Mine Sites

Source Applicability/Authorities

31 January 2003 31

Reclamation/PostreclamationTheoretically should be covered under new source permitting, major/minor

source issue effects authority; could also be addressed as part of permit

modification; may not be being considered

Inactive/Abandoned

Mines

Except under CERCLA, ongoing activity should be same regulatory and

permitting requirements as active operations; CERCLA actions exempted

from permitting but still must meet standards (PSD, NSPS, etc.)

Generators Point sources, may bring some entire mine sites into major source

requirements; also lower major source threshold for PSD/non-attainment

analysis may arise if greater than about 75 Mw

Note: Some fugitive sources (overburden, land application, etc.) are generally only evaluated when

making a major source determination.

5.2 Endangered Species Act

The Endangered Species Act of 1973 (ESA) requires Federal agencies to “insure that any

action authorized, funded, or carried out by such agency is not likely to jeopardize the continued

existence of any listed species or result in the destruction or adverse modification of critical

habitat of such species.” The purpose of the Act is “to provide a means whereby the ecosystems

upon which endangered species and threatened species depend may be conserved” and “to

provide a program for the conservation of such endangered species and threatened species . . .” 

Section 7 of the Act, as amended, outlines procedures for interagency cooperation to

conserve Federally listed species and designated critical habitats. Section 7(a)(1) requires

Federal agencies to use their authorities to further the conservation of listed species. Section

7(a)(2) requires Federal agencies to consult with the U.S. Fish and Wildlife Service (FWS)

and/or National Marine Fisheries Service (NMFS; hereafter referred to together as the Services)

to ensure that they are not undertaking, funding, permitting, or authorizing actions likely to

jeopardize the continued existence of listed species or adversely modify designated critical

habitat. For example, EPA will consult with the Services in the issuance of NPDES permits as

well as preparation of NEPA documentation. 

The roles and responsibilities of the Services in implementing the Act were described by

the Department of the Interior and the Department of Commerce in a 1974 Memorandum of

Understanding. NMFS is responsible for listed species that occur in marine environments,

including anadromous fish species such as salmon and steelhead that migrate from freshwater to

marine environments during a portion of their life cycle. The FWS is responsible for listed

species that are inland or nonmarine species. If listed salmon and trout species (e.g., bull trout)

occur within a project study area, both Services would be responsible for completing Section 7
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procedures. The Services also have joint jurisdiction over some listed species (FWS and NMFS,

1998).

The Section 7 consultation process is designed to assist Federal agencies in complying

with the Act. Figures 3A and 3B describe typical steps in the consultation process. Most

consultation is undertaken informally. First, a general description of the proposed action and a

formal request for a list of proposed, candidate and listed endangered and threatened species

potentially affected by the proposed action are submitted to the Services by the lead Federal

agency. The Services respond with a list of proposed, candidate, and listed species and/or

habitat that occur within the project study area. Although the inclusion of candidate species is

not required by law, the Services consider candidates when making natural resource decisions. 

If no species or habitat are present, consultation ends. If species and/or habitat are present and a

project involves major construction activity, a Biological Assessment (BA) must be prepared by

the Federal Agency. The BA identifies the project, summarizes the biology of the listed species,

analyzes the impacts of the proposed action, and determines if there is likely to be an effect

(either beneficial or adverse) on any listed species. The BA is then filed with the Services. If

species and/or habitat are present and the project involves actions other than “major construction

activity,” the Federal agency must still evaluate the potential for adverse effects and consult with

the Services. This may consist of preparing a Biological Evaluation (BE) or other type of report

to evaluate these effects.

If the BA or BE concludes that the proposed agency action “is likely to adversely affect”

any of the T&E species, formal consultation with the Services is required.

Formal consultation involves a more detailed review of the proposed action by the

Services. The formal consultation process determines whether a proposed agency action(s) is

likely to jeopardize the continued existence of a listed species or destroy or adversely modify

critical habitat. It also determines the amount or extent of anticipated incidental take of a listed

species. After collecting the best available scientific and commercial information on the listed

species, and reviewing the Federal Agency’s BA or BE, the Services prepare a Biological

Opinion (BO) that analyzes the impacts of the proposed action on the listed species. Three

possible conclusions are made in the BO: the proposed action (1) may promote the continued

existence of the species; (2) is not likely to jeopardize the continued existence of the species; or

(3) is likely to jeopardize the continued existence of the species. When the Services make a

determination that the proposed action is likely to jeopardize the continued existence of the

species, reasonable and prudent alternatives must be included in the BO. Reasonable and

prudent alternatives are alternative actions that can be implemented in a manner consistent with

the scope of the Federal agency’s action, that are economically and technologically feasible, and

that the Services believe would avoid jeopardy or adverse modification to the listed species, or

critical habitat, respectively. The BO may also include reasonable and prudent measures to

minimize impacts (i.e., amount or extent, or incidental take). 

Concurrent with planning for permitting and NEPA review, it is essential that proposed

mine operators work with the lead agency and the Services to plan for ESA compliance. 
EPA and Hardrock Mining: A Source Book for Industry in the Northwest and Alaska

33 January 2003 33

Biological surveys need to fully address the presence of proposed, candidate, threatened, and

endangered species and/or their habitat. Potential impacts need to be considered in preparing

plans of operations and permit applications. The lead agency will be responsible for ensuring

that final plans of operations/permitted activities are consistent with the findings of the

Biological Opinion. Specific reasonable and prudent measures and alternatives as well as

monitoring requirements identified in the Biological Opinion may be incorporated directly into

NPDES or other permits and Records of Decision issued by EPA. 

Non-Federal representatives (e.g., proposed mine operators) may participate in the

informal consultation process, including preparing draft BAs. The lead agency must designate

such representatives in writing to the Services. Regardless, ultimate responsibility for

compliance with Section 7 requirements remains with the lead agency (e.g., assuring that draft

BAs are technically sound). More information about the Act and consultation process is found

in the Endangered Species Consultation Handbook published by the Services in March 1998. 

This document is available from the USFWS website.

5.3 Resource Conservation and Recovery Act (RCRA)

Under the provisions of RCRA §3001(b)(1), solid waste from the extraction,

beneficiation, and processing of ores and minerals is exempt from regulation as hazardous waste

under RCRA Subtitle C. This section was added to RCRA in 1980 and is known as the “Mining

Waste Exclusion” or the “Bevill Amendment”– several other categories of wastes were also

excluded, and collectively these wastes are known as “special wastes.” This provision

precluded EPA from regulating these wastes until the Agency had performed a study and

submitted a Report to Congress, as directed by §8002(f) and (p), and determined either to

promulgate regulations under Subtitle C (that is, to regulate the wastes as hazardous wastes) or

that such regulations were unwarranted (that is, to continue the Exclusion of the wastes from

such regulation). EPA subsequently modified its final hazardous waste regulations to reflect this

new
EPA and Hardrock Mining: A Source Book for Industry in the Northwest and Alaska

34 January 2003 34

Figure 3A. Informal Consultation Under the Endangered Species Act
EPA and Hardrock Mining: A Source Book for Industry in the Northwest and Alaska

35 January 2003 35

Figure 3B. Formal Consultation Under the Endangered Species Act

(USFWS and NMFS, Endangered Species Consultation Handbook, 1998)
EPA and Hardrock Mining: A Source Book for Industry in the Northwest and Alaska

36 January 2003 36

exemption, and issued a preliminary interpretation of the scope of the exemption. Over the next

decade, there followed litigation, Reports to Congress, and rulemakings. These are not described

in detail here, but rather only the key decisions are highlighted. 

In 1985, EPA submitted the first Report to Congress, which addressed wastes from

mineral extraction and beneficiation. On July 3, 1986 (51 FR 24496), EPA published the

regulatory determination for these wastes, which stated that regulation of these wastes as

hazardous wastes was unwarranted. 

In the late 1980s, EPA proposed and promulgated a series of rules that redefined the

boundaries of the Exclusion for mineral processing wastes. These rulemaking notices provided

explicit criteria for making key distinctions between mineral beneficiation and processing and

for determining whether specific mineral processing wastes met certain other criteria and were

thus eligible for the Exclusion. The full rulemaking process was completed with the

promulgation of final rules on September 1, 1989 (54 FR 36592) and January 23, 1990 (54 FR

2322). 

Of all mineral processing wastes, only 20 were found to meet the newly promulgated

special waste criteria; all other mineral processing wastes were removed from the Mining Waste

Exclusion. On July 30, 1990, EPA submitted a Report to Congress on these 20 wastes. 

Subseqently, EPA made a regulatory determination that regulation of these wastes as hazardous

wastes was unwarranted. 

As a result of the rulemaking process, all but 20 mineral processing wastes lost their

special waste status, and assumed the same regulatory status as any other industrial solid waste. 

Therefore, if they exhibit one or more characteristics of hazardous waste, or are listed as

hazardous waste, they must be managed in accordance with RCRA Subtitle C or equivalent State

standards. 

EPA considers these wastes to be “newly identified” since they were brought into the

RCRA Subtitle C system after the date of enactment of the Hazardous and Solid Waste Act 

(HSWA) Amendments on November 8, 1984. EPA declined to include newly identified wastes

within the scope of the Land Disposal Restrictions (LDR) for Subtitle C characteristic hazardous

wastes (the “Third Third” rule) published on June 1, 1990, deciding instead to promulgate

additional treatment standards (Best Demonstrated Available Technology, or BDAT) in several

phases that would be completed in 1997 (55 FR 22667). EPA subsequently developed BDAT

treatment standards that must be met for characteristic hazardous mineral processing wastes. 

5.4 Coastal Zone Management Act

For mining operations proposed in areas that lie within a particular state’s coastal zone, a

consistency determination with respect to that state’s Coastal Zone Management Plan (CZMP)

will likely be required. The state agency responsible for implementing the federal Coastal Zone
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37 January 2003 37

Management Act in that particular state must concur that the proposed operation is consistent

with the state’s CZMP. The state’s concurrence with the consistency determination may in turn

require coordination with other state permitting agencies as well as at the local level where

elements of such plans are often developed. Prospective mine operators are encouraged to

identify and contact the appropriate state officials early in the mine planning process so that the

CZMP consistency determination can run concurrent with other regulatory processes. State

government websites are a good source of information for state regulatory programs, including

coastal zone planning requirements.

5.5 State Authorities

EPA is not responsible for implementing all or even most environmental programs. All Federal

environmental programs, including the Clean Water Act, the Clean Air Act, and many other

statutes, provide for State assumption of implementation authority upon passage of conforming

laws, development of appropriate regulations, and establishment of adequate mechanisms for

implementation. Table 7 shows the delegation status of all the major Federal environmental

programs in EPA Region 10, as of early 2003. Because NEPA is not a regulatory program but

rather places an obligation on Federal agencies to comply, there is no “authority” that can be

delegated under NEPA. 

Table 7. Delegation and Authorization of Federal Environmental Programs 

to States in EPA Region 10 (see note 1)

Statute/Program Alaska Idaho Oregon Washington

Clean Air Act

NSPS Partial delegation Partial delegation Partial delegation Partial delegation

NESHAPS Partial delegation Partial delegation Partial delegation Partial delegation

NSR Full delegation Full delegation Full delegation Full delegation

PSD Full delegation Full delegation Full delegation Partial delegation

MACT NESHAPS Partial delegation Partial delegation Partial delegation Partial delegation

Acid Rain n/a Full delegation Full delegation Full delegation

Title V (note 2) Interim approved Interim approved Full delegation Full delegation

SIPS (note 3) Ongoing approvals ongoing approvals Ongoing approvals Ongoing approvals

Clean Water Act

NPDES permitting Not delegated Not delegated Full delegation Full delegation

Pretreatment Not delegated Not delegated Full delegation Full delegation

Sludge Not delegated Not delegated Not delegated Not delegated
EPA and Hardrock Mining: A Source Book for Industry in the Northwest and Alaska

Table 7. Delegation and Authorization of Federal Environmental Programs 

to States in EPA Region 10 (see note 1)

Statute/Program Alaska Idaho Oregon Washington

38 January 2003 38

Federal facilities Not delegated Not delegated Full delegation Not delegated

Wetlands Not delegated Not delegated Not delegated Not delegated

Emergency Planning and Community Right-to-know Act

§§311 & 312 Not delegated Not delegated Not delegated Not delegated

Federal Insecticide, Fungicide, and Rodenticide Act

Enforcement (note 4) Full delegation Full delegation Full delegation Full delegation

Resource Conservation and Recovery Act

Base program (note 5) Not delegated Full delegation Full delegation Full delegation

Corrective action Not delegated Full delegation Full delegation Full delegation

Boilers & Industrial

Furnaces

Not delegated Full delegation Full delegation Not delegated

Toxicity

Characteristics Rule

Not delegated Full delegation Full delegation Full delegation

Land Disposal

Restrictions

Not delegated Partial delegation Partial delegation Partial delegation

Underground Storage

Tanks

Not delegated Not delegated Not delegated Full delegation

 Safe Drinking Water Act

UIC Class II wells Full delegation n/a Full delegation n/a

UIC Class I, III, IV, V n/a Full delegation Full delegation Full delegation

PWS Full delegation Full delegation Full delegation Full delegation

Toxic Substances Control Act

Lead Not delegated Not delegated Full delegation Not delegated

Notes:

n/a = not applicable

1 Partial and full delegations of programs to States do not apply in Indian Country, where EPA retains full

responsibility

2 Generally, States are implementing and carrying out a majority of the program but are constantly

updating their rules and EPA must approve before the State can fully implement.

3 Interim approved means EPA has approved the State to implement but some revisions are needed

before the final/full approval can be given. 

4 FIFRA delegation is for use violations only. Other Federal violations are referred to EPA. 

5 pre-HSWA program
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39 January 2003 39

Besides Federal programs that may be delegated to States, many States implement

programs specific to mining operations that have no direct EPA nexus. These generally require

State permits for various aspects of mining operations and closure, oversight of most or all

aspects of mining operations, and reclamation of mine sites to State- and site-specific standards. 

All States in EPA Region 10 have laws that require hardrock mining reclamation, and that

require some sort of financial assurance that reclamation can be achieved at the end of active

operations. 

These programs are not described in this Source Book, since EPA has no direct role in

their implementation. Most States have placed detailed information on these programs on their

websites. 

EPA notes, however, that state permit programs, including bonding programs, can be an

important factor in providing mitigation for predicted impacts, and can be crucial in ensuring

that proposed mitigation measures will actually be implemented. For these reasons, EPA

considers State regulatory and permit requirements, as well as bonding requirements, to be

important factors in its evaluation of potential impacts under NEPA

6.0 EPA EXPECTATIONS FOR MINING IMPACT ASSESSMENT

As discussed in Section 4, EPA’s primary direct responsibilities in Region 10 typically

relate to NPDES new source permitting of mines under the CWA and associated NEPA review. 

At the same time, many of the most significant issues regarding potential environmental impacts

from new mining operations involve water resources, aquatic habitat, jurisdictional wetlands and

other waters of the U.S. Consequently, EPA expects applicants to have a thorough

understanding of the hydrological and aquatic environment in which they are proposing to work. 

The NEPA review and CWA permitting processes will require that an applicant collect a variety

of data, conduct different types of analyses, and develop preliminary facility and operational

designs to define potential consequences on water resources. Examples of the types of data,

testing, and analysis that may be required are given in Tables 8 through 11. Tables 8 through 11

in turn refer to the technical appendices for more details. A general discussion of information

needs related to predicting impacts to surface water, ground water, and wetlands resources are

presented in the following sections.

6.1 Impacts to Surface and Ground Water Hydrology

Applicants need to address whether and to what extent their proposed project will affect

the surface water and ground water hydrology at the mine site and within the watershed. To

determine potential hydrological impacts will require collection and analyses of a variety of

meteorological and hydrological data (see Table 8), preparation of operation phase and closure

phase water balances (see Table 11), and wastewater and storm water management plans. 

Information regarding surface water discharge, precipitation, and the duration and intensity of

storm events are especially critical to this process. This is because most proposed sites are
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40 January 2003 40

located in mountainous, coastal, or subarctic areas where there are significant annual and

seasonal variations in climate that make it difficult to develop data sets that are representative

and statistically significant. To overcome the problems associated with high short-term data

variability requires a long-term record. However, most sites are likely to be proposed in remote

areas for which long-term records of discharge and climate are unlikely to be available either for

the watershed of interest or for nearby watersheds possessing similar physical characteristics. 

Consequently, in order to gather data for as long as possible, applicants should establish stations

to monitor stream discharge and meteorological conditions during the early stages of site

exploration. Information and analyses necessary to determining impacts to surface water and

ground water hydrology is discussed in the following sections and in more detail in Appendix

A, Hydrology.

6.1.1 Surface Water Hydrology

A proposed mining project can impact the quantity and velocity of surface water flow by

altering natural drainage patterns and the infiltration/runoff relationships in a watershed;

discharging storm water and wastewater; impounding water; changing the character of gaining

and losing stream reaches through mine dewatering; mining through stream channels and flood

plains; and by diverting, re-routing, and channelizing streams. Importantly, many mining

activities have the potential to alter the equilibrium balance between flow and sediment transport

in streams (Johnson, 1997). Altering this equilibrium causes stream gradients, channel

geometries, channel patterns, and stream banks to adjust to new equilibrium conditions that

reflect new erosion and sediment transport characteristics (Johnson, 1997). Such changes can

disrupt aquatic habitats both upstream and downstream of a mine. The creation of waste dumps,

tailings impoundments, mine pits and other facilities that become permanent features of the postmining landscape can cause fundamental changes in the physical characteristics of a watershed

(O’Hearn, 1997). Consequently, applicants may be required to assess the effect of these changes

on the post-mining hydrological environment. 

Most applicants will be required to complete hydrological studies and a site water

balance in order to predict impacts to surface water hydrology. These studies and their

associated data needs are summarized below and are described in more detail in Appendix A,

Hydrology.

The hydrological study should provide a baseline from which to measure or predict

relevant changes that might occur as a consequence of the proposed action and its alternatives. 

In order to place the project within the context of its watershed, the study should have a scope

that extends beyond the boundaries of the proposed mine site. As part of the study, applicants

should: 

• Characterize both surface and subsurface flow regimes and surface-ground water

interactions on a seasonal or monthly basis. Identify critical low flow conditions.
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41 January 2003 41

Table 8. Data Needs for NEPA Review and CWA Permits

Resource Area Data Needs Appendix

Climate Average annual precipitation; Monthly precipitation distribution;

Mean monthly temperature; Mean monthly evaporation; Storm

characteristics (precipitation rates); Orographic effects.

A

Geology and Soils Lithology and mineralogy of rocks, soils, and alluvial deposits;

Rock unit distribution; Structural relations; Fracture distribution &

characteristics; Alteration and mineralization, including vertical

and lateral changes; Surface-subsurface relationships;

Topography and slopes; Soil cover (depth and type).

C

Surface Water

Hydrology

Watershed delineation; Flood plain delineation; Identification of

special designation waters; Stream gradient, channel

morphology, channel pattern; Stream flow/sediment transport

relations; Stream flows (average monthly flow, critical low flows);

Flood frequency; Precipitation/infiltration/ runoff relations;

Gaining/losing reaches; Surface water usage.

A, B

Ground Water

Hydrogeology

Aquifer delineation; Aquifer characterization (storage, direction

of flow, gradient, permeability, transmissivity); Water table

elevation and its variability; Recharge zones; Confining layers;

Seeps & springs; Depth of permafrost thaw; Ground water

usage.

A, F

Surface Water and

Ground Water

Quality

Background surface and ground water quality; Existing surface

and ground water quality; Relationship of surface water quality to

changes in flow

A,B

Effluent Quality Expected quality of effluents and variability of effluent quality

over range of operating conditions; Expected flow of effluent and

variability of flow over range of operating and climatic conditions

D

Wetlands & Waters

of the U.S.

Delineation of wetlands & waters of the U.S.; Wetlands

classification; Designation of riparian habitat & corridors;

Narrative descriptions that include nature, extent, functions, and

value.

I

Aquatic Fish and macroinvertebrate population and diversity data;

Aquatic habitat characterization; aquatic mammals and

amphibians; Threatened, endangered, or sensitive species.

G

• Distinguish the effects that any current or historic activities, including mining

activities, have had on the hydrology of the project area

• Determine the extent to which different physical variables within the watershed

control hydrological processes
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42 January 2003 42

• Prepare an analysis of meteorological records that describes the seasonal

variability, frequency, and intensity of storm events. 

The baseline study should provide adequate data to evaluate whether the proposed mine

operation and considered alternatives could alter the hydrology of a watershed. This analysis

requires characterization of several watershed geomorphological and other characteristics, such

as basin slope, vegetative cover, soil type and land use conditions. In addition, applicants need

to demonstrate how construction of the proposed mine and its associated facilities might alter

runoff responses to both average and extreme precipitation events. Impacts to seasonal flow

regimes and channel morphology (i.e., channel bed and bank erosion and sediment transport

capacity) that can be caused by stream diversions, channelization, and altered drainage patterns

need to be defined. Effects on surface water discharge, and impacts to spring-fed wetlands or

stream reaches from mine dewatering activities should also be quantified.

Applicants must determine whether their proposed operation will result in discharges to

waters of the U.S.. An accurate assessment is accomplished by developing a thorough

understanding of local and regional hydrology and formulating a reliable water balance. An

adequate water balance superimposes the flow of process system waters (i.e., the process circuit)

on the natural hydrology within the watershed and describes the management of storm runoff,

flood flows, and process and storm water discharges on a seasonal or monthly basis. The water

balance should cover the range of hydrologic conditions (extreme and average) and potential

variations or disruptions in process flows (e.g., temporary suspension of operations as well as 

closure). The site water balance is used to determine whether a proposed mine would have a net

gaining system that may require continual or periodic discharges. 

Table 9. Testing Needs for NEPA Review and CWA Permits

Resource Area Testing Needs Appendix

Solid waste

characterization (e.g.,

Waste Rock, spent

heap leach & Tailings) 

Grain-size distribution; mineralogy, Total and sulfide sulfur

content; Acid generating potential; Acid neutralizing potential;

Kinetic test; leach tests; Total metals content; Leachate

compositions; Tailings water compositions.

C

Rock, Soils &

Sediment

Characterization

Proctor moisture/density; Atterberg limits; Grain-size analysis;

Direct shear; Permeability; Total metals content; Acid

generating potential; Acid neutralizing potential; leach tests.

C,F

Water Quality

Characterization

Major cation and anion concentrations; Metals concentrations

(total and dissolved); pH; conductivity; Redox potential;

Temperature; Total hardness; Total alkalinity; TDS; TSS;

Dissolved oxygen, Whole effluent toxicity (WET) tests.

A,B, D 

Hydrologic

Characterization

In situ hydraulic conductivity; Monitor well logs; Drawdown

studies; Aquifer transmissivity and storage.

A
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43 January 2003 43

Table 10. Preliminary Design Needs for NEPA Review and CWA Permits

Resource Area Preliminary Design Needs Appendix

Mine Operation Mine plan; Facilities layout. - 

Infrastructure Road locations and construction; Stream crossings; Fuel

storage; Borrow areas; Water and wastewater treatment plants.

-

Beneficiation Mineral processing methodology; Reagent storage; Facility

construction; Conveyance systems; Ore and concentrate

stockpiles.

-

Waste Disposal Tailings impoundments and piles; Waste rock and spent ore

dumps; Overburden storage areas.

F

Process Water

Management

Process water flow chart; Storage ponds; Conveyance

structures; water balances

D,E

Storm Water

Management

Diversion structures; Conveyance structures; Retention ponds. E

Closure and

Reclamation

Best Management Practices; Heap leach neutralization and

rinsing; Revegetation mixes; Grading and recontouring; Natural

and synthetic covers; Facility removal; Pit wall or mine tunnel

stabilization.

E, F, H

Methods to measure and predict hydrological impacts and develop a site water balance

are described in Appendix A, Hydrology. Region 10 recognizes that many mines proposed in

northern and central Alaska are likely to be situated in areas underlain by permafrost. In these

terrains, stream flow and precipitation-infiltration-runoff relations vary seasonally due to winter

freeze. Applicants proposing to work in these areas should give special consideration to their

unique hydrological characteristics and to seasonal variations.

6.1.2 Ground Water Hydrogeology 

A proposed mining operation can impact the availability and flow of ground water by

locally lowering the water table through dewatering operations; disrupting aquifers; locally

removing confining layers; and altering zones of natural recharge (Brown, 1997). Mining

activities also create opportunities for ground water contamination by exposing aquifers and

puncturing aquitards. Alteration of ground water flow direction or reduction in the water table or

potentiometric surface can potentially impact wetlands, aquatic habitats, and stream discharge

characteristics.
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44 January 2003 44

Most applicants will be required to submit a detailed hydrogeologic study of the region in

which they are proposing to operate. This study and its associated data needs are summarized

below and described in detail in Appendix A, Hydrology.

Table 11. Data Analysis Needs for NEPA Review and CWA Permits

Resource Area Data Analysis Needs Appendix

Waste Rock & Tailings

Disposal Impact

Predict short- and long-term acid generating potential and

metals leachability; rates of seepage and run-off; predict

stability of piles, impoundments, and backfill

C,F

Surface Water &

Ground Water Quality

Impact

Statistical analysis of water quality data; Estimated effluent

discharge composition; Estimated seepage composition;

Projected effects of discharge on ground and surface water

quality; Estimated pit-lake water quality; Projected likelihood of

ground and surface water quality impacts from spill events. 

Ground-water models used to assess impacts should be

updated annually through operations and the impacts

determination should be modified if the model changes

significantly. 

A,B,D

Hydrological Impacts Facility water balance; Design storm models; Watershed model

(e.g., HEC-1); Flow duration curves; Pit lake development

model; Ground water flow model (e.g., MODFLOW); Storm

water flow model; Sediment erosion and transport model;

Dewatering, drawdown, and recovery; Changes in recharge

characteristics.

A,H

Wetlands & Aquatic

Life Impact

Calculated impacted acreage by wetland type, loss of function

and value. Potential impacts on fish and macroinvertebrate

populations through toxicity, reduced flow, and habitat loss.

B,I,G

The hydrogeological study should provide a baseline from which to measure or predict

changes that might occur as a consequence of the proposed action and its alternatives. The

boundaries of the study have to be defined on site specific basin, and may need to encompass the

entire watershed. As part of the study, applicants should:

• Identify aquifers and confining layers and their vertical and lateral extent

• Determine the types of aquifers (confined or unconfined), aquifer characteristics

such as hydraulic conductivity, primary and secondary porosity, storage

coefficients, and hydraulic gradient, and hydraulic communication, if any, with

surface water or other ground waters
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45 January 2003 45

• Characterize each confining layer and its physical properties

• Determine the depth to water, the configuration of the water table or

potentiometric surface, and the hydraulic gradient and flow direction

• Where required, quantify the seasonality of ground water flow in permafrost

terrains

• Distinguish the effects that any current or historic activities, including mining

activities, may have had on the hydrogeology of the project area.

Region 10 expects applicants to provide analyses of potential impacts to ground water

resources caused by water use and mine dewatering. Dewatering of surface and underground

mines can deplete aquifers, impact ground water recharge and discharge, and locally change the

direction of ground water flow. For these reasons, data collected for hydrogeological studies

should be used to conduct an analysis of the potential impacts of drawdown. This analysis

should determine the extent that ground water levels or specific yield would be affected and

whether lowering of the water table or reducing the potentiometric surface would impact spring

flow, wetlands, gaining stream reaches, or other ground water users. In some cases, an analysis

of geotechnical effects caused by drawdown may be required to adequately design mine

facilities, impoundments, embankments, and foundations. For example, dewatering a

comparatively thick, unconsolidated alluvial aquifer that overlies an undulating bedrock surface,

could cause differential compaction, consolidation, and uneven surface subsidence. These

effects could threaten the geotechnical stability of facilities such as tailing dams and the integrity

of engineered structures such as process pond liners. Data collected during dewatering

operations should also be used to predict the rate at which the ground water system is expected

to recover following active operations.

Hydrogeologic studies conducted in terrain underlain by permafrost will need to

characterize the conditions unique to this sensitive environment. Included are the seasonality of

ground water flow in the near surface environment, the depth of annual thaw, potential

connections between shallow and deep (below the permafrost layer) ground waters, the

importance of vegetative layers, and the potential for mining-induced thawing of frozen

materials (either by excavation of insulating vegetation or rock layers or construction of

permanent facilities such as tailings impoundments).

The hydrogeologic study should provide a basis for assessing the recovery of the ground

water regime following mining. This includes estimating the rate at which ground water levels

would recover and describing potential effects caused by the formation of pit lakes, the

disruption of recharge zones (especially those associated with confined aquifers), the influx of

seepage waters from permanent mine facilities (e.g., tailings impoundments), the removal of

confining layers, the disruption of aquifer continuity, and the back-filling of mine pits (Siegel,

1997). 
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46 January 2003 46

6.2 Impacts to Water Quality

Impacts to surface and ground water quality can occur from discharges of storm water,

mine drainage, and process water. This section summarizes information needs regarding

potential impacts to water quality. Appendices A and B provide detailed guidance for

characterizing hydrology and receiving water quality at the appropriate watershed scale.

Two issues that applicants will be required to address during the NEPA review and CWA

permitting processes are whether the proposed project is expected to lead to a discharge of

wastewater and whether the proposed project would create short- or long-term impacts to surface

or ground water quality. EPA places great emphasis on evaluations of potential wastewater

discharges because once mining operations have been initiated, discharges often cannot be

stopped or reduced if the effluent does not meet water quality standards. Historically, the most

problematic discharges occur from major mine components that are exposed to the atmosphere,

such as mine pits, waste rock dumps, tailings impoundments, and leach facilities. Because mine

wastes will be exposed to the elements long after mine closure, the potential for the release of

metals, acid, cyanide, sediment, or other contaminants from a mine site must be accurately

analyzed. Evaluating the potential for long-term risk from waste disposal practices is a difficult

task but it is of primary importance to demonstrating compliance with the CWA and in

disclosing accurate information to the public. Factors associated with evaluating long-term

impacts include:

• Characteristics of waste rock, tailings, and other waste materials

• Facility design and construction

• Beneficiation and processing methods

• Local meteorological and hydrological conditions

• Solid waste and wastewater management methods

• Closure and reclamation methods.

Determining potential impacts to water quality typically requires applicants to collect a

variety of data, conduct numerous geochemical tests, develop preliminary mine plans and facility

designs, and perform different types of data analyses. In general, applicants should anticipate

that they may be required to provide studies that characterize:

• Background surface and ground water quality within the watershed hosting the

proposed operation 

• Background surface water hydrology and ground water hydrogeology in the

watershed of interest
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47 January 2003 47

• Expected hydrologic, physical, and geochemical behavior of waste rock piles,

heap leach piles, and tailings impoundments, and other waste materials during

operation and following closure 

• Chemical compositions of process waters, mine drainage, and treated and

untreated effluent

• Effectiveness of rinsing, neutralization, and closure and reclamation methods

employed for these facilities

Each of these items are discussed in the following subsections.

6.2.1 Background and Existing Water Quality

Methods to determine background and existing water quality in a watershed are discussed

in Appendix B, Receiving Waters; testing needs and data analyses are summarized in Tables 9

and 11, respectively. As described in the appendix, applicants should employ robust statistical

techniques to analyze background metals and other constituent concentrations in different

portions of a potentially impacted watershed, quantify the magnitude of seasonal variability in

water quality and variation associated with high and low stream flow conditions, and evaluate

water quality under the conditions of highest risk (i.e., reasonable worst-case conditions). 

Adequate quality assurance and quality control should be demonstrated. For example, analytical

methods employed must be sensitive enough to measure the parameters of concern at levels at or

below the water quality criteria. 

6.2.2 Regional Hydrology and Hydrogeology

The hydrology and hydrogeology studies described in Section 6.1 should provide data to

evaluate potential future water quality impacts. Applicants for NPDES permits should develop a

surface water management plan and site water balance that also can be used when evaluating

potential water quality impacts.

 

6.2.3 Hydrology of Mines and Waste Facilities

Predictions of whether and when a mine or waste disposal facility may begin to generate

acidic water or to release metals or other constituents are related to the flow of fluids through the

facility, the compositions of these fluids, the compositions of the materials with which the fluids

are in contact, and the chemical environment in which the fluids exist. Accurate predictions of

effluent flow rate and discharge composition require knowledge of waste characteristics, surface

and ground water hydrology, effectiveness of proposed surface water and ground water controls,

final unit construction and closure methods, climate, geochemical equilibrium, and other

variables that may be difficult to determine during the permitting process. Consequently,

applicants for mines that could generate acid or mobilize metals should employ facility designs
EPA and Hardrock Mining: A Source Book for Industry in the Northwest and Alaska

48 January 2003 48

that minimize infiltration and seepage and use conservative estimates for acid generation

potential, rainfall, and leachate composition to determine future impacts. 

In general, the hydrological and hydrogeological studies described in Section 6.1, and in

more detail in Appendix A, will provide data to determine the likelihood that lakes will form in

open pits and that underground workings will flood when mining ceases. Although the rate at

which lake filling or underground flooding is expected to occur can be estimated from

knowledge of pre-mining ground water flow, data collected during actual dewatering operations

can be used to provide a clearer picture of the expected post-closure conditions. 

The long-term hydrological behavior of waste rock dumps and tailings impoundments

depends on factors such as construction method, grain size and sorting of the waste materials,

secondary mineral formation, and closure and reclamation methods (Blowes et al., 1991; MEND,

1995; Swanson et al., 1998). Predicting seepage rates can be difficult, especially for facilities

that are likely to be partially saturated, such as those located in dry climates (Swanson et al.,

1998). Generating acceptable model simulations is even more complicated for facilities

constructed in such a way that they are physically heterogeneous (e.g., discontinuous layers of

coarse and fine waste rock) (Swanson et al., 1998) or within which layers of secondary mineral

cements formed during weathering (Blowes et al., 1991). More detail regarding the prediction of

hydrologic impacts of waste rock dumps and tailings impoundments is provided in Appendix F,

Solid Waste Management and Appendix A, Hydrology.

6.2.4 Solid Waste and Materials Characterization and Management 

 Applicants will need to demonstrate that they have adequately characterized their waste

materials and the potential for these materials to contribute to discharges to surface waters and

groundwater. Tests commonly used to characterize bulk chemical and physical composition,

metals leachability, and acid-generating potential are summarized in Tables 9 and 11 and

described in Appendix C, Characterization of Ore, Waste Rock, and Tailings. Because there are

many different tests available to determine leachability and acid-generating potential and no

single accepted way of interpreting test results, applicants should consult with federal and state

regulatory agencies to enquire whether specific test methods are preferred.

Applicants should demonstrate that the samples characterized are representative of

material that will be produced during operations. There are no set guidelines for determining the

number of samples that should be tested. Recent studies suggest that the number of tested

samples should be determined by the compositional variability of the materials that will be

disposed of (Shields et al., 1998) — this has long been understood in terms of characterizing ore

grade, and applicants should apply the same care in characterizing environmental samples. 

Applicants are expected to describe the variability inherent in different lithological units across

the project area (e.g., homogeneous, unzoned granite vs. heterogeneous colluvium) and that may

have been imparted to a lithological unit through weathering, hydrothermal alteration, and

mineralization. Applicants will need to consider how vertical and lateral changes in the intensity

and style of mineralization and host rock alteration affect the acid generating characteristics and
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49 January 2003 49

metals leachability of each geologic unit at the proposed mine site. Because compositional

variability equates primarily to mineralogical variability, applicants can use inexpensive

examinations (e.g., mineralogical analysis by x-ray diffraction, possibly followed by

petrographic microscope) to quantify the range and median proportions of acid-forming, acidneutralizing, and metal-bearing constituents in the various lithological units that will be

encountered. Testing programs can then focus on characterizing the expected behavior across

the compositional range identified for each rock type. 

For many large-scale operations, it may be appropriate to formulate composite test

samples which represent waste rock and overburden materials as they are likely to be excavated

and handled during the mining operation. It is important that composite samples be created in a

manner representative of the proposed operation. 

Tailings test samples should be taken from pilot-scale metallurgical tests representative

of the operation that will be employed during full-scale operation. Applicants should test ore

samples that capture the range of ore grades that will be processed during the life of the mine.

Of particular concern to EPA and the public is the potential for waste rock, tailings, and

heap leach materials to generate acidity and release metals after protracted exposure to the

environment. Tests of several years duration conducted on mine materials indicate that

acidification may occur after periods of neutral drainage lasting one to two years (Lapakko et al.,

1998), even in the accelerated weathering environment of the lab. Applicants should recognize

that static acid-base accounting tests provide information only on the relative proportions of

acid-forming and acid-neutralizing components in a sample and provide no information

regarding the rates at which these reactions are expected to occur. Information regarding the

latter can only be obtained by kinetic tests that are conducted for a sufficiently long time. 

Kinetic tests typically are conducted for 20-week periods; however, there is a trend toward using

longer test times (Price et al. [1997] advocate 40-week tests) that would be viewed favorably by

Region 10. 

The results of static and kinetic tests are particularly sensitive to the test method and

laboratory technique. EPA Region 10 encourages applicants to conduct all tests using the same

test method and testing laboratory. In addition, although not specifically stated in most kinetic

test procedures, Mills (1998) points out that it is typical for splits of the starting kinetic sample

and final leached product to be tested for static acid-base properties and total metals.

Mineralogical analyses also should be conducted on these samples because these data can

provide important constraints to assist the interpretation of test results.

Interpreting the results of leach tests, static acid-base accounts, and kinetic tests is not

straightforward and there are no generally accepted criteria for doing so (see Appendix C). This

is because the conditions simulated by the tests inevitably will deviate from the environment in

which wastes will be disposed and because many test methodologies require that samples be

crushed or ground to particle sizes significantly finer than produced by the mining operation

(Doyle et al., 1998; Lapakko et al., 1998). Changes in particle size are particularly important,
EPA and Hardrock Mining: A Source Book for Industry in the Northwest and Alaska

50 January 2003 50

because crushing alters the exposed surface areas of both acid-forming and acid-neutralizing

materials, which in turn affects reaction rates and availability (Lapakko et al., 1998). To ensure

that interpretations of geochemical test results are appropriately conservative, applicants should

carefully consider the representativeness of the tested samples, the similarities and differences

between the test conditions and site environment, and the significance of any temporal changes

in leachate compositions noted over the course of the tests. In addition, specialized knowledge is

required for proper evaluation of the characterization results, and applicants need to ensure that

their data are evaluated by individuals with this knowledge.

Applicants should also provide information useful for predicting impacts on water

quality. These include information on the effects of previous mining, pre-mining water quality,

and relevant geologic factors (e.g. rock type, effects of surface weathering). This type of

information can be particularly valuable in identifying the potential for metals leaching in the

absence of acidic conditions.

Management of solid wastes and information needs related to NEPA analyses of potential

impacts due to solid waste are discussed in Appendix F, Solid Waste Management. Applicants

proposing operations that will produce acid- or metals-generating waste rock or tailings should

provide design elements that will limit potential environmental impacts from these materials. 

These could include steps to minimize the production of potentially reactive wastes, separation

and special handling of these materials, blending acid-generating and neutralizing materials,

and/or reclamation designed to isolate these wastes from the environment.

6.2.5 Wastewater Quality and Management

The NPDES permit process requires applicants to identify sources of wastewater and

storm water, describe wastewater and storm water management, provide water balances, and

estimate the quantities and compositions of effluents that would be discharged through permitted

outfalls throughout the year (see Table 5). Applicants must demonstrate that the wastewater

characterization is representative of discharges that will occur over the full range of operating

conditions and closure and that any effluent proposed for discharge will not result in water

quality standards exceedences in the receiving water. In order to accomplish this, applicants will

need to estimate the quantities and compositions of process solutions, tailings water, runoff

waters, mine drainage, and treated effluent at the proposed operation and the effectiveness of

wastewater management measures (such as treatment). 

Wastewater quality and quantity from tailings impoundments and operating heap leach

facilities may be determined from analysis of process solutions and tailings waters obtained from

pilot-scale metallurgical tests that simulate the proposed processing operations. Discharges from

waste rock piles and mine drainage may be predicted based on geochemical testing and

modeling. For operations proposed in areas of historic mining activity, samples of mine

drainage should be collected from pit lakes, underground workings, tailings ponds, or seeps

emanating from existing waste disposal facilities. Where wastewater treatment is proposed, the

quality of treated effluent should be determined from pilot-scale tests of the proposed treatment
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51 January 2003 51

technology. Wastewater management, including discussions of treatment processes, treatability

studies, methods for disposal, and data needs for NEPA analyses are discussed in Appendix E,

Wastewater Management. Methods to predict discharge effluent quality are described in

Appendix D, Effluent Quality.

6.2.6 Post-Closure Mine and Waste Facility Water Quality 

Predictive assessments of post-mining pit lake or underground water quality and tailings

impoundment water quality will likely be required by the NEPA process. Predictions may be

made based on results of geochemical testing and modeling. There may be a high degree of

uncertainty associated with predictive modeling. Stochastic models, those containing

information regarding parameter uncertainty, are gaining wider acceptance as predictive tools

(Schafer and Lewis, 1998). Where models are used, assumptions and uncertainties associated

with the model and input parameters must be identified. It is also beneficial for the Applicant to

make sure in advance that the model will be accepted by the regulatory agencies. 

Mining activities that disrupt ground water geochemical systems can spur mineral

dissolution or precipitation reactions that can alter pre-mining ground water quality in ways that

may be difficult to predict (Lewis-Russ, 1997). Mine pits that are backfilled with waste rock and

underground workings that are abandoned following ore extraction increase the opportunity for

contamination by exposing ground water to fresh rock surfaces that are not in equilibrium with

the existing geochemical system. In these situations, applicants should provide an assessment of

potential ground water quality impacts in these settings. 

More detail regarding predictive water quality models is provided in Appendix D and

Appendix A.

6.2.7 Closure and Reclamation Effects 

The methods used for facility closure and reclamation can play an important role in

determining the potential for long-term contamination. Residual leach fluids or soluble metal

complexes that remain in inadequately rinsed or neutralized heaps can lead to seepage of metalsladen acidic or cyanide-rich fluids. However, low permeability caps, covers, and capillary

barriers installed following recontouring can lower the risk of long-term contamination by

helping to reduce infiltration and chemical flux through the embankment. In addition,

adequately established vegetation cover would reduce erosion and aid in the evapotranspiration

of water from surface layers. Caps and covers also can help to limit oxygen diffusion into

sulfide-bearing waste materials. Grading and recontouring of facility slopes can reduce the

potential for long-term erosion, slope failure, and sedimentation in surface waters. Other Best

Management Practices (BMPs) may be employed to minimize contamination due to

sedimentation and erosion (see Appendix H). Applicants will be required to develop preliminary

closure and reclamation plans for NEPA review which should address whether or not an NPDES

permit will be required for any post-closure discharges. Closure considerations and related

NEPA disclosure needs are discussed in more detail in Appendix F, Solid Waste Management
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52 January 2003 52

and Appendix H, Erosion and Sedimentation. In addition, information on expected post-mining

water quality should be provided for the NEPA analysis.

6.3 Impacts to Aquatic Resources

Freshwater aquatic resources represent an important component of the environment that

must be analyzed for NEPA review and CWA permitting processes. Considerable overlap exists

between studies analyzing aquatic resources and those characterizing surface water and ground

water quality and hydrology. Many impacts to aquatic resources, including riparian areas, are

related to mine construction and the location of facilities. Road construction, logging, and

clearing of areas for buildings, mills, and process facilities can reduce infiltration and increase

the amount of surface runoff which reaches streams and other surface water bodies while

potentially reducing stream base flows. This can increase the peak flow and the total amount of

stream discharge which occurs from a given storm event. Unusually high peak flows can cause

erosion of stream banks, widening of primary flow channels, erosion of bed materials,

channelization, and alteration of the slope of the channel. These impacts can affect and degrade

aquatic habitats, including riparian zones. Channelization (i.e., straightening) can increase flow

velocities in a channel reach, potentially affecting fish passage to upstream reaches during

moderate to high stream flows. Increased erosion and downstream sedimentation can impact

spawning gravels, egg survival, and frye emergence, as well as degrade benthic food sources and

riparian cover. Flooding can create high velocity flows, scour stream banks and erode or bury

gravel substrates. The destruction of cover created by large woody debris and stable banks can

impact rearing and resting habitat for fishes. In addition, removing riparian vegetation can

reduce shading. The resulting increase in sunlight can raise the temperature at the surface and

through the entire water column, and this in turn can have a profound impact on the entire

aquatic ecosystem. 

Water quality issues associated with mine exploration, operation, and abandonment

activities typically involve the potential discharge of mine water and process solutions, increased

loads of metals and other toxic pollutants, acid generation from waste rock, spent ore, and mine

workings. If these pollutants reach surface waters, toxic conditions could affect important

aquatic species.

Studies that are typically required for NEPA review and often CWA §404 permitting

include analyses of fish, benthic macroinvertebrates, and the physical parameters, including the

riparian zone, that define habitat for aquatic communities. In the NEPA process, aquatic

resources, especially fish, often represent significant issues for the proposed action being

evaluated. This is because resident and anadromous fisheries represent a concern to the public

and governmental agencies such as NMFS, BLM, USFWS, U.S. Forest Service (USFS), Tribal

governments, and state wildlife agencies. Many fish species, particularly salmonids (trout and

salmon), have important recreational and/or commercial fishery values. Numerous species also

are Federally or state-listed species that require protection under the Endangered Species Act. 

For these reasons, applicants should complete analyses to determine potential impacts to aquatic
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53 January 2003 53

resources. Appendix G, Aquatic Resources provides detailed discussion of data needs and

outlines methods to design appropriate studies for aquatic resources.

The aquatic resources study should provide a baseline from which to measure or predict

relevant changes that might occur as a consequence of the proposed action and its alternatives. 

As required under NEPA regulations, an impact assessment must analyze both direct, indirect

and cumulative impacts to important aquatic resources located within the project study area

(Council on Environmental Quality, 1986). The study should have a scope that extends beyond

the boundaries of the proposed mine site. Applicants should anticipate that they could be

required to provide studies that characterize or evaluate:

• Potential effects of water quality changes on aquatic communities and their

habitat that may result from mine operations, including point and non-point

source discharges, and changes in flow regimes. Parameters of concern may

include heavy metals, pH, total dissolved solids, cyanide and cyanide breakdown

products (e.g., ammonia, nitrogen compounds), and overall effluent toxicity.

• Potential effects of sedimentation on aquatic communities and their habitat as a

result of construction and operational activities. 

• Potential effects of physical disturbance or removal of aquatic habitat and

associated riparian area on aquatic biota.

• Potential effects to aquatic biota from spills that occur during the transport or

storage of fuel, process chemicals, and other hazardous materials.

• Potential effects of stream flow changes on aquatic habitat and biota that result

from water withdrawals (both of ground and surface water), stream diversions, or

discharges.

• Potential effects of physical blockages or barriers created by mine construction or

operation activities on fish movements. These evaluations should include

potential velocity barriers that can be created in diversions, culverts, or road

crossings which can affect fish passage through a stream reach.

These types of impact evaluations would normally include background studies that define

fish distribution, abundance and species composition, and critical habitat for spawning, frye

emergence, and juvenile rearing. These studies need to focus especially on game and species

listed as threatened and endangered (T&E) or special status. Fishery habitat studies should

include, among other factors, characterization of stream gradients, widths, depths, pool

frequency, substrate composition, instream and riparian vegetation, and the presence of large

woody debris. Background studies to characterize macroinvertebrate communities should define

species composition and abundance and provide community metric data, such as species richness

and species diversity.
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6.4 Impacts to Wetlands

Studies to define, delineate and determine potential impacts to wetlands and other waters

of the U.S. typically have more rigorous requirements than studies conducted to evaluate nonwetlands because jurisdictional wetlands (and other waters of the U.S.) are regulated under

Section 404 of the CWA. In general, wetlands are aquatic areas within the landscape that

include swamps, marshes, fens, bogs, vernal pools, playas, prairie potholes, and riparian zones. 

These features are considered to be “jurisdictional wetlands” if they exhibit specific conditions

of wetland hydrology, hydric soils and the presence of hydrophytic vegetation, as defined by the

accepted delineation method. The regulatory definition of wetlands and the criteria and

indicators used to identify them are discussed in detail in Appendix I, Wetlands and Other

Waters of the United States. Regulatory requirements as specified under §404 of the CWA are

discussed in section 3.0. 

Wetlands may perform a variety of important physical, chemical and biological functions

including ground water recharge or discharge, flood storage, peak flood flow attenuation,

shoreline and channel bank anchoring, dissipation of erosive forces, sediment trapping, and

nutrient trapping and removal. Wetlands may also provide habitat for numerous plant, wildlife,

and fish species, including some that are listed as threatened and endangered (T&E). 

Impacts to wetland areas can result from the construction and operation of mine and

facilities including construction and use of roads; site preparation for buildings, mills and

ancillary facilities; and the construction, use and maintenance of waste and storage facilities,

such as tailings impoundments and waste rock dumps. Impacts can occur either directly or

indirectly. Direct impacts include the removal or destruction of wetlands through dredging,

filling, or draining. Indirect impacts are those associated with increased runoff and erosion from

disturbed areas, increased sedimentation, and increased loadings of metals and other toxic

pollutants. Mining operations also can impact riparian areas, which may be destroyed or lost by

the construction of stream diversions or by altering drainage patterns within a watershed. Mine

dewatering activities may impact wetland hydrology and wetland functions by altering regional

ground water recharge and discharge characteristics. 

Any proposed project or activity with a potential to impact wetlands, either directly or

indirectly, will be required to fully characterize this resource to establish baseline conditions, and

determine potential impacts. It is important to note that state and local governments may also

place restrictions on projects that could impact wetlands, regardless of their jurisdictional status

under CWA §404.

The wetland study should provide a baseline from which to measure or predict changes

that might occur as a consequence of the proposed action and its alternatives. Studies to

determine potential impacts to wetlands should be described in terms of acreage of absolute loss

(acres filled or drained) and in loss of wetland function. Applicants should anticipate that they

may be required to provide studies that characterize or determine:
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55 January 2003 55

• The classification of wetlands and their function both within and near the project

area

• The acreage of wetlands that will be directly impacted by fill or draining activities

• The extent that changes in hydrology, drainage patterns, or stream discharges

would affect the hydrology of identified wetlands and the composition of

associated plant species

• The extent to which dewatering activities or ground water withdrawals would

affect wetland hydrology and function

• Potential increased sediment loading to identified wetlands

• Fate and transport of spilled process chemicals or hazardous wastes and the

potential for spills to impact wetlands

• Potential effects to aquatic and terrestrial wildlife habitat and habitat values from

impacted wetlands.

In conducting studies, applicants should specifically evaluate different mine layouts,

facility designs, and technologies to study the avoidance and minimization of environmental

impacts to wetlands. The Section 404(b)(1) guidelines indicate that 404 permits can only be

issued when no practicable alternatives exist that would have fewer adverse impacts to wetlands. 

Where proposed activities cannot avoid impacts to wetlands, studies must demonstrate that

practicable steps have been taken to minimize potential adverse impacts. In some cases,

operators have been able to offset lost wetland acreage with developed wetlands, or by

upgrading/improving other wetlands.

7.0 REFERENCES

Blowes, D.W., Reardon, E.J., Jambor, J.L., and Cherry, J.A., 1991. The Formation and Potential

Importance of Cemented Layers in Inactive Sulfide Mine Tailings, Geochimica

Cosmochimica et Acta, vol. 55, pp. 965-978.

Brown, A., 1997. Groundwater Quantity. In: Marcus, J.J., ed., Mining Environmental

Handbook, Effects of Mining on the Environment and American Environmental Controls

on Mining, Imperial College Press, London, pp. 244-248.
EPA and Hardrock Mining: A Source Book for Industry in the Northwest and Alaska

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Council on Environmental Quality, 1986. Regulations for Implementing the Procedural

Provisions of the National Environmental Policy Act, Executive Office of the President,

40 CFR Parts 1500-1508.

Doyle, T.A., Murphy, S.F., Klein, S.M., and Runnels, D.D., 1998. A Comparison of Batch and

Column Leaching Tests of Mining Wastes, Society for Mining, Metallurgy, and

Exploration, Inc., Preprint 98-103, 5 pp.

Johnson, S.W., 1997. Surface Water Quality - Sediment. In: Marcus, J.J., ed., Mining

Environmental Handbook, Effects of Mining on the Environment and American

Environmental Controls on Mining, Imperial College Press, London, pp. 149-150.

Lapakko, K., Haub, J., and Antonson, D., 1998. Effects of Dissolution Time and Particle Size on

Kinetic Test Results, Society for Mining, Metallurgy, and Exploration, Inc., Preprint 98-

114, 9 pp.

Lewis-Russ, A., 1997. Ground Water Quality. In: Marcus, J.J., ed., Mining Environmental

Handbook, Effects of Mining on the Environment and American Environmental Controls

on Mining, Imperial College Press, London, pp. 162-165.

MEND, 1995. Hydrology of Waste Rock Dumps, Natural Resources Canada and the Mining

Association of Canada Mine Environment Neutral Drainage Program, MEND Associate

Project PA-1, July 1995.

Mills, C., 1998. Kinetic Testwork Procedures, Report posted on the Enviromine website,

http://www.enviromine.com/ard/Kinetic%20Tests/kinetic%20procedures.htm, viewed

October 14, 1998.

O’Hearn, J., 1997. Surface Water Quantity. In: Marcus, J.J., ed., Mining Environmental

Handbook, Effects of Mining on the Environment and American Environmental Controls

on Mining, Imperial College Press, London, pp. 221-225.

Price, W.A., Morin, K., and Hurt, N., 1997. Guidelines for the Prediction of Acid Rock

Drainage and Metal Leaching for Mines in British Columbia: Part II. Recommended

Procedures for Static and Kinetic Testing. Proceedings - Fourth International

Conference on Acid Rock Drainage, Vancouver, B.C., Canada, May 31 - June 6, 1997.

Schafer, W.M. and Lewis, M., 1998. Evaluating the Environmental Risk of Water Quality

Impacts at Mining Sites, Society for Mining, Metallurgy, and Exploration, Inc., Preprint

98-182, 9 pp.

Shields, M.J., Runnells, D.D., and Jones, R.L., 1998. Methodology for Adequacy of Sampling

Mill Tailings and Mine Waste Rock, Society for Mining, Metallurgy, and Exploration,

Inc., Preprint 98-23, 2 pp.
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Siegel, J., 1997. Ground Water Quantity. In: Marcus, J.J., ed., Mining Environmental

Handbook, Effects of Mining on the Environment and American Environmental Controls

on Mining, Imperial College Press, London, pp. 165-168.

Swanson, D.A., Kempton, J.H., Travers, C., and Atkins, D.A., 1998. Predicting Long-Term

Seepage from Waste-Rock Facilities in Dry Climates, Society for Mining, Metallurgy,

and Exploration, Inc., Preprint 98-135, 7 pp.

U.S. Environmental Protection Agency, Office of Wastewater Management, 1996. NPDES

Permit Writers’ Manual. EPA 833-B-96-003. 

U.S. Environmental Protection Agency, Office of Water, 1982, The Development Document for

Effluent Limitations Guidelines and Standard for the Ore Mining and Dressing Point

Source Category. EPA 440/1-82/061.

U.S. Environmental Protection Agency, Office of Water, 1991. Technical Support Document for

Water Quality-based Toxics Control. EPA 505/2-90-001.

U.S. Environmental Protection Agency, Region 6, EID Handbook Guidance to Applicants for

New Source NPDES Permits. 1995

U.S. Fish and Wildlife Service and National Marine Fisheries Service, Endangered Species

Consultation Handbook. 1998