MANAGEMENT OF MINING WASTES
RCRA SUBTITLE D
REGULATORY PROGRAM DEVELOPMENT
DETAILED MANAGEMENT PLAN
U.S ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF SOLID WASTE
WASHINGTON, D.C.
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MANAGEMENT OF MINING WASTES
RCRA SUBTITLE D REGULATORY PROGRAM DEVELOPMENT
DRAFT
MANAGEMENT PLAN
U.S. Environmental Protection Agency
0££ice of Solid Vaste
Washington, DC
June 22, 1987
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TABLE OF CONTENTS
Page
EXECUTIVE SUMMARY ES-1
1. INTRODUCTION 1-1
1.1 BACKGROUND AND PURPOSE 1-1
1.2 GOALS 1-3
1.3 OVERVIEW OF KEY TASKS AND MILESTONES 1-6
1.3.1 Outline of Key Tasks for Subtitle D Regulatory
Development 1-7
1.3.2 Outline of Key Tasks for Second Report to
Congress 1-9
1.3.3 Outline of Key Tasks for Third Report to
Congress 1-10
1.4 PROJECT MANAGEMENT AND STAFFING 1-10
1.5 MANAGEMENT PLAN ORGANIZATION 1-14
2. MAJOR ACTIVITIES IN REGULATORY DEVELOPMENT PROCESS 2-1
2.1 PURPOSE 2-1
2.2 SUBTITLE D REGULATORY DEVELOPMENT 2-1
2.2.1 Data Compilation, Collection, and Evaluation 2-1
2.2.1.1 Summary and Evaluation of Existing
Information and Creation of Data
Management System 2-3
2.2.1.2 Compilation and Review of CERCLA Site
Information 2-5
2.2.1.3 Development of Technical Issue Papers... 2-5
2.2.1.4 Site Visits 2-6
2.2.1.5 Review of Federal and State Programs.... 2-7
2.2.1.6 Develop and Conduct Section 3007
Survey (s) 2-8
2.2.1.7 Risk Screening Methodology 2-9
2.2.1.8 Focused Data Collection: Specific
Studies and Modeling Activities 2-9
2.2.2 Regulatory Development Activities 2-10
2.2.2.1 Development of Issues and Options 2-10
2.2.2.2 Model State Program 2-11
2.2.2.3 "Straw Man" Regulatory Program 2-12
2.2.2.4 Regulatory Impact Analysis 2-12
2.2.2.5 Regulatory Support Document 2-12
2.2.2.6 Development and Proposal of Subtitle D
Regulatory Program 2-13
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TABLE OF CONTENTS (Continued)
Page
2.3 SECOND REPORT TO CONGRESS 2-14
2.3.1 Identification of Bevill Boundaries 2-16
2.3.2 Compilation of Existing Information 2-16
2.3.3 Compilation of CERCLA Site Information 2-16
2.3.4 Compilation of Information from 1984
Section 3007 Survey 2-17
2.3.5 Risk. Assessment 2-17
2.3.6 Review of Existing Federal and State Programs.... 2-17
2.3.7 Scoping for Third Report to Congress 2-18
2.3.8 Report Preparation, Review, and Submission 2-18
2.3.9 Regulatory Determination 2-18
2.4 THIRD REPORT TO CONGRESS 2-20
2.4.1 Determining the Scope of the Report 2-20
2.4.2 Data Compilation and Collection 2-22
2.4.2.1 Compilation of Existing Information 2-22
2.4.2.2 Compilation of CERCLA Site Information.. 2-22
2.4.2.3 Primary Data Collection . 2-22
2.4.2.4 Section 3007 Survey 2-22
2.4.3 Report Preparation, Review, and Submission 2-22
2.4.4 Regulatory Determination 2-23
3. COMMUNICATIONS STRATEGY 3-1
3.1 INTERNAL COMMUNICATIONS 3-1
3.1.1 Agency Offices with Significant Involvement 3-1
3.1.2 Mining Waste Regulatory Development Workgroup.... 3-4
3.1.3 Steering Committee 3-7
3.2 EXTERNAL COMMUNICATIONS 3-8
3. 3 CONGRESSIONAL COMMUNICATIONS 3-10
4. REGULATORY AND TECHNICAL BACKGROUND, APPROACH, ISSUES, AND
DATA COLLECTION NEEDS 4-1
4.1 PURPOSE 4-1
4.2 STATUTORY AND REGULATORY BACKGROUND 4-1
4.2.1 RCRA Statutory and Regulatory Background 4-2
4.2.2 Other Federal Statutes and Programs 4-3
4.2.3 State Programs 4-7
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TABLE OF CONTENTS (Continued)
Page
4.3 TECHNICAL BACKGROUND 4-8
4.3.1 Types and Amounts of Mining Wastes 4-8
4.3.2 Technical Issues Summaries 4-12
4.3.2.1 Acid Generation 4-12
4.3.2.2 Mobile Toxic Constituents - Water 4-13
4.3.2.3 Mobile Toxic Constituents - Air 4-15
4.3.2.4 Radioactivity 4-16
4.3.2.5 Asbestos 4-17
4.3.2.6 Cyanide 4-19
4.3.2.7 Direct Human Contact and Misuse 4-20
4.3.2.8 Catastrophic Failure 4-21
4.3.2.9 Common Technical Issues 4-22
4.3.3 Descriptions of Mining Segments 4-25
4.3.3.1 Copper 4-25
4.3.3.2 Lead and Zinc 4-28
4.3.3.3 Gold and Silver 4-30
4.3.3.4 Uranium 4-32
4.3.3.5 Phosphate 4-33
4.3.3.6 Asbestos 4-34
4.3.3.7 Molybdenum 4-34
4.3.3.8 Aluminum 4-34
4.4 CONCEPTUAL PROGRAM DESIGN... 4-35
4.5 PRELIMINARY REGULATORY DEVELOPMENT ISSUES 4-39
4.5.1 Issue 1: Overall Approach to the Rulemaking 4-41
4.5.1.1 Issue 1A: What Should be the Regulatory
Approach 4-42
4.5.1.2 Issue IB: How Should the Present
Administrative and Enforcement
Authorities under Subtitle D be Revised
for Mining Wastes? 4-44
4.5.2 Issue 2: What Should the Relationship Between
the Subtitle D Program and Existing
Regulatory Structures 4-45
4.5.3 Issue 3: Potential Scope of the Subtitle D
Program 4-46
4.5.3.1 Issue 3A: How should the Regulations
Apply to Abandoned, Inactive, New, and
Existing Facilities and Sites? 4-46
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TABLE OF CONTENTS (Continued)
Page
4.5.3.2 Issue 3B: What is the Relationship
Between RCRA and CERCLA Standards at
Mining Sites? 4-48
4.5.3.3 Issue 3C: What are the Boundaries of
the Bevill Exclusion at Processing
Facilities? 4-49
4.5.3.4 Issue 3D: What are the Regulatory
Distinctions Between Process Materials
and Wastes? 4-50
4.5.3.5 Issue 3E: How should Waste Management
Controls be Applied to Combined
Extraction, Beneficiation, and
Processing Sites? 4-51
4.5.3.6 Issue 3F: Which Mining Segments
Should be Considered in Future Subtitle
D Rulemaking Efforts? 4-52
4.5.4 Issue 4: What Are the Technical Methodologies
and Standards Needed to Support the
Rulemaking? 4-53
APPENDICES Page
A. TECHNICAL ISSUE PAPER 1: ACID GENERATION A-l
B. TECHNICAL ISSUE PAPER 2: MOBILE TOXIC CONSTITUENTS - WATER B-l
C. TECHNICAL ISSUE PAPER 3: MOBILE TOXIC CONSTITUENTS - AIR C-l
D. TECHNICAL ISSUE PAPER 4: RADIOACTIVITY D-l
E. TECHNICAL ISSUE PAPER 5: ASBESTOS E-l
F. TECHNICAL ISSUE PAPER 6: CYANIDE F-l
G. TECHNICAL ISSUE PAPER 7: DIRECT HUMAN CONTACT AND MISUSE G-l
H. TECHNICAL ISSUE PAPER 8: CATASTROPHIC FAILURE H-l
I. TECHNICAL ISSUE PAPER 9: COMMON TECHNICAL ISSUES 1-1
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LIST OF TABLES AND FIGURES
Table Page
ES-1 Schedule of Major Activities Supporting Subtitle D Mining
Waste Regulatory Program Development ES-7
1-1 States with Extraction, Beneficiation, and Processing
Sites Addressed in First Two Reports to Congress 1-5
2-1 Major Activities for Subtitle D Regulatory Development 2-2
2-2 Major Activities for Second Report to Congress 2-15
2-3 Mining Industry Segments Under Consideration for Third
Report to Congress 2-19
2-4 Major Activities for Third Report to Congress 2-21
4-1 Mining Industry Segments Addressed in the Current Subtitle D
Rulemaking 4-26
Figure
ES-1 Critical Activities in Mining Waste Regulatory Development... ES-6
1-1 Location and Numbers of Extraction, Beneficiation, and
Processing Sites Addressed in First Two Reports to Congress.. 1-4
1-2 Critical Activities in Mining Waste Regulatory Development... 1-8
1-3 Project Staffing and Responsibilities 1-12
1-4 Management Structure for Mining Waste Regulatory Development. 1-13
3-1 Overview of Communications Strategy 3-2
4-1 Typical Mining Industry Site and Waste Types 4-11
4-2 Conceptual Program Design: Tiered Approach 4-37
4-3 Example of Assessment Methodology: Acid Generation 4-40
H-l Basic Mechanics of Slope Failure Mechanics H-5
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EXECUTIVE SUMMARY
Purpose of Management Plan
This Mining Waste Management Plan is intended to provide senior managers
and others with a description of the tasks being undertaken to accomplish the
objective described belov. The Management Plan vill provide a tracking system
by which Project Directors and others may track the status of various tasks
and deadlines and identify the parties responsible. It also will serve as a
source of materials to be used by Project Directors and members of the
Regulatory Development Workgroup in briefing their managers and others. In
addition, the Plan will provide a ready mechanism by which personnel new to
the project and other interested parties may understand both the technical and
regulatory/statutory background of the project and its objectives.
The overall objective of the activities described in this Management Plan
is the development of a regulatory program, under Subtitle D of the Resource
Conservation and Recovery Act (RCRA), for the management of wastes from the
extraction, beneficiation, and processing of ores and minerals. The activi-
ties being undertaken to accomplish this objective are extremely complex and
their successful completion demands detailed planning by the Project Directors
and management. Three major efforts are involved in accomplishing the overall
objective: the preparation and submission of two separate reports to Congress
and the preparation and proposal of the regulatory program itself (Chapter 2
describes the specific activities being underaken for each effort). Three
contractors are providing support to EPA: Camp Dresser and McKee (CDM) is
providing technical support, Science Applications International Corporation
(SAIC) is providing policy support, and ICF Incorporated is providing risk and
economic modeling support (Chapter 2 identifies the major activities for which
each contractor will be responsible). Three broad constituencies are also
interested in the process: internal Agency offices, external agencies and
organizations (including several Federal agencies, many States, and many
private parties), and Congress. Establishing early and effective communica-
tions among these parties will be vital to the project; the Communications
Strategy described in Chapter 3 will enable all constituencies to participate
in the process.
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Background
EPA has long recognized that the "unique practical demands of mining
operations" require a tailored approach to mining waste management. Regula-
tions proposed on December 18, 1978, to implement Subtitle C of RCRA placed
specific requirements on the management of hazardous portions of "special
wastes" (which included mining wastes). (The proposed requirements were later
withdrawn.)
Currently, all wastes from the extraction, beneficiation, and processing
of ores and minerals are conditionally excluded by RCRA Section
3001(b)(3)(A)(ii) (the Bevill amendment) from regulation as hazardous wastes
under Subtitle C of RCRA. Thus, these mining wastes fall within the
jurisdiction of Subtitle D of RCRA (Subtitle D covers all solid wastes that
are not regulated as hazardous wastes under Subtitle C) and other laws
administered by States and other Federal authorities. EPA is required, under
Sections 8002(f) and (p) of RCRA, to study and prepare report(s) to Congress
on wastes from the extraction, beneficiation, and processing of ores and
minerals. After conducting such studies and submitting reports to Congress on
the results, EPA must determine which of the wastes, if any, should be
regulated as hazardous wastes under Subtitle C of RCRA. To date, EPA has
completed one Section 8002 study and report to Congress (dated December 31,
1985); this study and report covered wastes from the extraction and beneficia-
tion (i.e., mining and milling) of metallic ores (including copper, gold,
iron, lead, silver, zinc, antimony, beryllium, mercury, molybdenum, nickel,
platinum, rare-earth metals, and vanadium), uranium overburden, asbestos,
phosphate rock, and oil shale. It was determined (July 3, 1986; 51 FR 24496)
that these wastes should not be regulated under Subtitle C. Rather, it was
determined that a special Subtitle D program should be developed that is
specific to the special characteristics and practical difficulties of mining
waste management. (See Section 4.2 for a detailed history of EPA's actions
concerning mining waste and for descriptions of existing Federal and State
programs.)
On October 2, 1985 (50 FR 40292), EPA proposed to narrow the exclusion
under the Bevill Amendment and to regulate under Subtitle C certain wastes
ES-2
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from the processing of copper, lead, zinc, aluminum, and ferroalloys.
However, this proposal was withdrawn on October 9, 1986 (51 FR 36233) because
there were inadequate criteria for determining which processing wastes should
be excluded. At the same time, EPA announced its commitment to proceed with
additional studies and reports to Congress required under Section 8002 of
RCRA, with certain processing (i.e., smelting and refining) wastes to be
addressed in the first of these studies and reports. Two of these additional
studies and reports to Congress are described in this Management Plan. (Both
the regulatory determination not to regulate extraction and beneficiation
wastes under Subtitle C and the withdrawal of the proposed reinterpretation of
the Bevill exclusion have been challenged in court, with oral arguments
scheduled to begin December 11, 1987.)
This Management Plan provides a detailed overview of and schedules for
all rulemaking, data collection, and communications activities; key Agency and
contractor responsibilities; major milestones; and key technical and policy
issues analyses needed to develop regulations under Subtitle D of RCRA for
specific segments of the mining industry that were addressed in the December
1985 Report to Congress and to prepare two reports to Congress on specific
segments of the mining industry.
Activities that support the rulemaking are the highest priorities in this
management plan. Efforts will therefore, be made to expedite these activities
wherever possible. The Management Plan includes the second report to Congress
because the initial Subtitle D regulatory program will address any wastes
covered in this report that are determined not to be appropriate for regula-
tion under Subtitle C. Although the initial Subtitle D program will not cover
any wastes addressed in the third report to Congress (in large part because of
scheduling reasonsany wastes not appropriate for Subtitle C regulation may
be covered in the future), this report is included in the Management Plan
because information developed in preparing this report will be critical in
ensuring that the rule will be appropriate for conditions (e.g., designs,
operating procedures, waste types) at sites within the mining segments that
may be covered by the Subtitle D program in the future.
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Chapter 1 of the Management Plan provides a general background and
summary of the regulatory development process and describes project management
and staffing. Chapter 3 describes the means by which the concerns of all
interested parties will be considered in the development of the regulatory
program. Chapter 4 presents the statutory and regulatory background, under
RCRA and other Federal and State statutes, to the current rulemaking.
Chapter 4 also describes several technical and regulatory issues that will be
addressed as the rulemaking proceeds. Technical issues are described more
fully in Appendices A through I.
Overview of Project Management and Staffing
The two Project Directors for this effort are Dan Derkics, the Chief of
the Large Volume Waste Section in EPA's Office of Solid Waste (OSW), and
Robert Walline, the Mining Waste Team Leader in Region 8. Mr. Derkics will
report to Truett DeGeare, the Chief of OSW's Special Wastes Branch, and
Mr. Walline will report to Jeffery Denit, the Deputy Director of OSW (see
Figure 1-4 in Chapter 1).
Most Agency personnel with specific responsibilities for project tasks
are either in OSW's Large Volume Waste Section or are Region 8 staff members
(see Figure 1-3). Other EPA project staff include personnel from other OSW
organizational units as well as from the Office of Policy, Planning, and
Evaluation; Office of Research and Development; Office of General Counsel;
Office of Congressional Liaison; Office of Water; and the Office of Air and
Radiation (see Section 3.1 for a full description of internal communications).
A total of 7.8 full-time equivalents (FTEs) are expected to be assigned to the
project, 5.8 FTEs at Headquarters and 2.0 in Region 8. The fiscal year 1987
budget is $2,200,000.
As noted above, three separate firms are assisting in the effort. Camp
Dresser & McKee (CDM) is the prime contractor for technical support and for
the third report to Congress. ICF Incorporated is responsible for the second
report to Congress and for risk and economic modeling. Science Applications
International Corporation (SAIC) is providing program management and policy
support. Chapter 2 describes in detail the tasks and deliverables for which
EPA and contractor personnel are responsible.
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Summary and Schedule of Major Activities
EPA initially stated its hope that the program would be developed by
"mid-1988." The complexity of the issues involved, the amount of data
collection that will be necessary, and other factors have resulted in the
current schedule, which calls for the regulatory program to be proposed in
April 1989. The factors responsible for the current schedule include:
The need to address all potential release pathways (e.g., many
individual sites have the potential for more than one of the environ-
mental problems described as technical issues in Section A.3.2 and
appendices; in addition, the same or similar environmental problems
can occur in several different industry segments)
The necessity to evaluate existing waste characterization methods and
the possible need to develop and/or adopt new ones
The inclusion of processing wastes from four industry segments in the
Subtitle D program (at the time of the determination to develop a
Subtitle D program specific to mining waste, EPA had proposed to
exclude most processing wastes from the Bevill exclusion)
The necessity of communicating and cooperating with many interested
parties, including Congress and other Federal agencies
The need to collect additional data to support development of the
regulatory program and the Regulatory Impact Analysis.
The processes of regulatory development and of preparation of reports to
Congress require an intricate, well-designed schedule inasmuch as the activi-
ties are inter-related and, to some extent, interdependent. Figure ES-1 and
Table ES-1 present the major milestones and key activities and the relation-
ships between the activities that must occur to complete the rulemaking pro-
cess and both reports to Congress. Detailed schedules and descriptions for
these activities are presented in Chapter 2. The scope and extent of many
later activities, particularly data collection activities, will depend upon
the results of earlier tasks. Thus, many later tasks cannot be described
precisely or scheduled accurately at this time. As each ongoing task is
completed (or is reasonably complete), details of subsequent tasks will be
developed. The schedules provided in this Management Plan, therefore, become
increasingly less detailed and less firm for tasks planned for later in the
life of the project. The Management Plan will be updated to reflect future
plans as appropriate.
ES-5
June 22, 1987
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PAGE NOT
AVAILABLE
DIGITALLY
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TABLE ES-1. SCHEDULE OF MAJOR ACTIVITIES SUPPORTING SUBTITLE D HI HI IK WASTE REGULATORY PROGRAM DEVELOPMENT
Activity
1981
JFMAMJJA50ND
1988
JFMAMJJASOND
1989
J F M A M J
Start Action Request 2389
Regulatory Development Plan
Management Plan
o (Jan. 21\
| op {April 1)
| D o- (Juno 19)-
C*J
cn
i
¦*«4
Subtitle D Regulatory Development
Data compilation, collection, and
evaluation
Regulatory development activities
Publication of proposed program
i-
i~
Phase I-
-Phase II-
Second Report to Congress
(on selected processing wastes)
Report preparation, review, and
submission
Regulatory determination
-| (Jan. 25)
o (July 25)
<_
C
9
ho
ro
CO
Vj
Third Report to Congress
Scoping
Data compilation and collection
Report Preparation, Review, and
Submission
Regulatory Determination
-Phase I 1 Phase II
-| (Jan. 25)
(July 251
Workgroup Meetings
o
o
o
o o
o
o
0 0
o o
o 0
0
Workgroup Reports to Steering
Couittee
o
o
o
o
0
o
o
o
o
o
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The regulatory development process has begun by:
Identifying and analyzing Federal and State Laws that are applicable
to the mining industry
Characterizing the industry segments to be regulated
Summarizing the technical and environmental concerns associated with
mining operations
Developing a preliminary conceptual program design for regulating
mining wastes, and
Identifying key program issues and concepts to be reviewed by EPA
senior management.
Current progress on these and other activities is described in Chapter 2.
Currently, mining and mining wastes are regulated under a variety of
Federal and State authorities. The Federal statutes described in Chapter 4
include:
The Comprehensive Environmental Response, Compensation, and Liability
Act (CERCLA, or Superfund)
The Mining Law of 1872, as amended
The Mineral Leasing Act of 1920
The Federal Land Policy Management Act of 1976
The Organic Administration Act of 1976
The Federal Water Pollution Control Act
The Clean Air Act
The Safe Drinking Water Act, and
The Uranium Mill Tailings Radiation Control Act of 1978.
A brief summary of some of the provisions in State mining laws is also
presented in Chapter 4.
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The manner in which the various regulatory agencies administer existing
programs that regulate mining waste management practices are not well docu-
mented, and the relationships between and among programs are not well known.
EPA will therefore be collecting information on these programs, and their
implementation, to help determine how best to structure the Subtitle D program
and how to coordinate the new program with existing State and Federal
programs. This data collection activity is described in Chapter 2.
The Agency is characterizing the types and amounts of wastes generated
by those segments of the mining industry that are addressed in this rule-
making. The Agency also has prepared nine technical issues papers that define
the Agency's current understanding of the potential for and environmental
impacts of releases from various types of mining operations. The issues
papers prepared thus far address: acid generation, mobile toxic constituents
in air and water, radioactivity, asbestos, cyanide, direct human contact and
misuse, catastrophic failure, and common technical issues. Summaries of these
issue papers are presented in Section 4.3.2; the full texts constitute
Appendices A through I.
The Agency has prepared a preliminary conceptual design for the regula-
tion of mining wastes. This design describes one risk-based approach that
could be taken to identify and regulate mining operations and wastes that pose
risks to human health and the environment. It includes a stepwise permitting
program that would apply increasing levels of onsite analyses (and regulatory
requirements) until all significant risks at a site are identified and
addressed. This program concept would allow low-risk sites to conduct fewer,
less-costly analyses, while focusing public and private resources toward more
detailed analyses at high-risk sites. This conceptual design is presented in
Section 4.4 of the Management Plan to elicit comments from all potentially
interested parties. The design is in a preliminary stage of development, and
will require detailed technical, legal, and policy analyses before it can be
either approved by the Agency or rejected in favor of an alternative program
design.
The Agency has identified a number of program concepts and issues for
review by EPA senior managers. Preliminary issues include:
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Issue 1A: What should be the regulatory approach?
Issue IB: How should the present administrative and enforcement
authorities under Subtitle D be revised for mining wastes?
Issue 2: What should be the relationship between the Subtitle D
program and existing regulatory structures?
Issue 3A: How should the regulations apply to abandoned, inactive,
new, and existing facilities and sites?
Issue 3B: What is the relationship between RCRA and CERCLA standards
at mining sites?
Issue 3C: What are the boundaries of the Bevill exclusion at
processing facilities?
Issue 3D: What are the regulatory distinctions between process
materials and wastes?
Issue 3E: How should waste management controls be applied to combined
extraction, beneficiation, and processing sites?
Issue 3F: Which mining industry segments should be considered in
future Subtitle D rulemaking efforts?
Issue 4: What are the technical methodologies and standards needed to
support the rulemaking?
These issues are discussed in Section 4.5, and current and anticipated
future data collection activities are outlined for each issue.
ES-10
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CHAPTER 1
INTRODUCTION
Page
1.1 BACKGROUND AND PURPOSE 1-1
1.2 GOALS 1-3
1.3 OVERVIEW OF KEY TASKS AND MILESTONES.: 1-6
1.3.1 Outline of Key Tasks for Subtitle D Regulatory
Development 1-7
1.3.2 Outline of Key Tasks for Second Report to
Congress 1-9
1.3.3 Outline of Key Tasks for Third Report to
Congress 1-10
1.4 PROJECT MANAGEMENT AND STAFFING 1-10
1.5 MANAGEMENT PLAN ORGANIZATION 1-14
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CHAPTER 1
INTRODUCTION
1.1 BACKGROUND AND PURPOSE
EPA has long recognized that the "unique practical demands of mining
operations" require a tailored approach to mining waste management.
Regulations proposed on December 18, 1978, under Subtitle C of the Resource
Conservation and Recovery Act (RCRA), placed specific requirements on the
management of hazardous portions of "special wastes" (which included mining
wastes). (The proposed requirements were later withdrawn.) In part, the
sheer volume of mining wastes accounts for the necessity of tailored require-
ments. EPA has estimated that about 300 million tons of wastes, produced in
1981 by all industries combined, were regulated as hazardous under RCRA
Subtitle C; one or a few mining operations can account for this volume of
mining waste. For example, in selected mining industry segments addressed in
the December 1985 report to Congress, extraction and beneficiation activities
(i.e., mining and milling) generated approximately 1.3 billion tons of mining
waste, of which over 800 million tons were potentially hazardous.
This Management Plan addresses the means by which EPA intends to fulfill
its announced commitment to develop a regulatory program under Subtitle D of
RCRA for the management of mining waste. Currently, all wastes from the
extraction, beneficiation, and processing of ores and minerals are condi-
tionally excluded by RCRA Section 3001(b)(3)(A)(ii) (the Bevill amendment)
from regulation as hazardous wastes under Subtitle C of RCRA. Thus, these
mining wastes fall within the jurisdiction of Subtitle D of RCRA (which covers
all solid wastes that are not regulated as hazardous wastes under Subtitle C)
and other laws administered by States and other Federal authorities. EPA is
required, under Sections 8002(f) and (p) of RCRA, to study and prepare
report(s) to Congress on wastes from the extraction, beneficiation, and
processing of ores and minerals. After conducting such studies and submitting
the results in reports to Congress, EPA must determine which of the wastes, if
any, should be regulated as hazardous wastes under Subtitle C of RCRA. To
date, EPA has completed one Section 8002 study and report to Congress (dated
December 31, 1985); this study and report covered wastes from the extraction
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and beneficiation (i.e., mining and milling) of metallic ores (including
copper, gold, iron, lead, silver, zinc, antimony, beryllium, mercury,
molybdenum, nickel, platinum, rare-earth metals, and vanadium), uranium
overburden, asbestos, phosphate rock, and oil shale. It was determined
(July 3, 1986; 51 FR 24496) that these wastes should not be regulated under
Subtitle C. Rather, it was determined that a special Subtitle D program
should be developed that is specific to the special characteristics and
practical difficulties of mining waste management. (See Section 4.2 for a
detailed history of EPA's actions concerning mining waste and for descriptions
of existing Federal and State programs.)
On October 2, 1985 (50 FR 40292), EPA proposed to narrow the exclusion
under the Bevill Amendment and to regulate under Subtitle C certain wastes
from the processing of copper, lead, zinc, aluminum, and ferroalloys. How-
ever, this proposal was withdrawn on October 9, 1986 (51 FR 36233) because
there were inadequate criteria for determining which processing wastes should
be excluded. At the same time, EPA announced its commitment to proceed with
additional studies and reports to Congress required under Section 8002 of
RCRA, with certain processing (i.e., smelting and refining) wastes to be
addressed in the first of these studies and reports. Two of these additional
studies and reports to Congress are described in this Management Plan.
This Mining Vaste Management Plan is intended to provide EPA senior
managers and other interested parties with a description of the tasks being
undertaken. The Management Plan has been developed so that its readers can be
kept up to date on the status of activities on a regular basis. Purposes of
the Management Plan include:
Providing a ready mechanism for personnel new to the project and other
interested parties to understand both the technical and regulatory/
statutory background of the process.
Providing a management tracking system for Project Directors and other
interested personnel regarding responsible parties, deadlines, and
status of different tasks.
Serving as a source of materials to be used by Project Directors and
members of the Regulatory Development Workgroup in briefing their
managers and others.
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1.2 GOALS
The major goal of the activities described in this Management Plan is the
development of a Federal regulatory program specific to mining wastes. As
stated in the regulatory determination that a Subtitle D program for mining
wastes would be developed (51 FR 24496; July 3, 1986), the program should:
Protect human health and the environment;
Address the technical feasibility, environmental necessity, and
economic practicality of mining waste controls;
Consist of a tailored risk-based approach that addresses the diversity
and unique characteristics of mining waste problems;
Consider existing Federal and State mining waste programs with a view
toward avoiding duplication of effort.
The regulatory program will be confined initially to wastes addressed in
the first two reports to Congress (i.e., to the extraction and beneficiation
wastes addressed in the December 1985 Report to Congress, and to any pro-
cessing wastes addressed in the second report (described below and in Section
2.3) that are determined not to be appropriate for regulation under Subtitle
C). However, the program to be developed is intended to be sufficiently
flexible to allow additional mining wastes to be covered in the future, if
appropriate1. Figure 1-1 and Table 1-1 show the locations and numbers of
extraction, beneficiation, and processing sites in the industry segments that
will be covered in the initial Subtitle D program.
xFor example, any wastes addressed in the third report to Congress that are
determined not to be suitable for regulation as hazardous wastes will be
brought into the Subtitle D program in the future. In addition, other mining
wastes may be addressed in future Section 8002 studies and reports to
Congress. In general, these wastes are not likely to present the same level
of potential risks as wastes covered in the earlier reports because industry
segments and wastes addressed in the first three reports were, and are being,
selected in part because of the potential risks they present. In addition,
EPA may decide to regulate, under the current rulemaking, some wastes that
have not been included in reports to Congress or may decide that some wastes
should not be regulated.
1-3
June 22, 1987
-------
I
O
c
3
(D
N>
N)
vO
00
-«-J
Extraction/Beneficiation Sites
Processing Sites (A), Cu, Pb, Zn)
Sources of Data-
Extraction and Benc
-------
D/834-052-00d/#21
TABLE 1-1. STATES WITH EXTRACTION, BENEFICIATION, AND PROCESSING
SITES ADDRESSED IN FIRST TVO REPORTS TO CONGRESS
Number of Sites1
State Extraction/Beneficiation Processing
Alabama
1
1
Alaska
0
0
Arizona
292
12
Arkansas
3
1
California
14
0
Colorado
52
0
Florida
23
0
Georgia
1
1
Idaho
23
0
Illinois
1
1
Indiana
0
1
Iowa
1
0
Kentucky
1
2
Louisiana
0
3
Maryland
0
2
Michigan
4
2
Minnesota
18
0
Missouri
10
4
Montana
12
2
Nebraska
0
1
Nevada
30
0
New Jersey
1
0
New Mexico
21
3
New York
3
2
North Carolina
1
1
Ohio
0
1
Oklahoma
0
1
Oregon
2
2
Pennsylvania
2
2
South Carolina
0
1
South Dakota
2
0
Tennessee
7
3
Texas
5
8
Utah
15
2
Vermont
1
0
Washington
3
7
West Virginia
0
1
Wyoming
6
0
Virgin Islands
0
1
TOTALS
292
68
1The numbers represent numbers of sites, not volumes or proportions of wastes
generated.
2The number of sites in the five States with the most sites in each category
are highlighted with bold type.
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As noted above, the Management Plan also covers the completion of two
additional Section 8002 studies and reports to Congress as part of the
regulatory development process. (In this Management Plan, these two studies
and reports are referred to as the "second" and "third" studies and reports.
Similarly, the December 1985 Report to Congress on extraction and beneficia-
tion wastes is referred to as the "first report.") Activities to complete the
second report include a comprehensive study (using existing data) under RCRA
Section 8002 of processing wastes from selected mining segments and a report
to Congress on the results (industry segments include aluminum, copper, lead,
and zinc). The results of the study must be adequate to allow:
The submission of a report to Congress by January 25, 1988;
t A regulatory determination to be made on which, if any, of the wastes
should be regulated as hazardous under Subtitle C;
The inclusion in the new Subtitle D program of the processing wastes
that are determined not to be appropriate for regulation under
Subtitle C of RCRA.
The processing wastes selected for this second report were chosen because
existing data allow the Section 8002 study and report to Congress to be
written on a "fast track" schedule. This "fast track" schedule will allow any
wastes determined not to be appropriate for regulation under Subtitle C to be
included in the Subtitle D regulatory program for mining wastes.
For the third report, initial activity involves the identification of
mining wastes that may be appropriate for Subtitle C regulation that have not
been addressed in previous reports to Congress. Data will be compiled and
collected, a Section 8002 study on these wastes will be conducted, and a
report to Congress will be prepared. This study and report should be com-
pleted by January 25, 1988, and must be adequate to allow a regulatory deter-
mination to be made on whether any or all of the wastes studied should be
regulated under Subtitle C.
1.3 OVERVIEW OF KEY TASKS AND MILESTONES
The processes of regulatory development and of preparing Section 8002
studies and reports to Congress require an intricate, well-designed schedule
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inasmuch as the activities are inter-related and, to some extent, inter-
dependent. The scope and extent of many later activities, particularly data
collection activities, will depend on the results of earlier tasks. Thus,
many later tasks cannot be described precisely or scheduled accurately at this
time. As each ongoing task is completed (or is reasonably complete), details
of subsequent tasks will be developed. The schedules provided in this
Management Plan, therefore, become increasingly less detailed, and less firm,
for tasks undertaken late in the life of the project. The Management Plan
will be updated in the future as appropriate.
To the extent that they can be described at present, brief descriptions
of the tasks under each major activity are provided below, and in detail in
Chapter 2 of this Management Plan. Figure 1-2 illustrates selected critical
activities and their interrelationships.
1.3.1 Outline of Key Tasks for Subtitle D Regulatory Development
The regulatory development process was formally initiated on January 21,
1987, with the Steering Committee's closure memorandum on Start Action Request
number 2389. The Steering Committee reviewed the draft Regulatory Development
Plan (RDP) on March 18, and a final RDP was distributed on April 1.
As described previously, the initial regulatory program will cover
extraction and beneficiation wastes addressed in the first report to Congress
as well as such processing wastes addressed in the second report as are
determined not to be appropriate for regulation under Subtitle C. To the
extent that the regulatory program will specifically address individual wastes
or industry segments, development of the program must await the completion of
the second Section 8002 study and report to Congress.
Compilation of existing information, site visits, criteria and methods
assessment and development, one or more Section 3007 industry survey(s),
predictive model development, and other activities are all anticipated to be
instrumental in providing the information necessary to develop a regulatory
program. Section 2.2 describes these activities in more detail, and
Section 4.5 relates the activities to various preliminary issues and options.
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AVAILABLE
DIGITALLY
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A key to the regulatory development process will be the timely development and
resolution of issues and options. Of immediate interest are the issues
described in Chapter 4 (e.g., the overall approach of the regulatory program
and the relationship between EPA and existing regulatory authorities) and
other issues that may require relatively rapid resolution. Issues and con-
cepts will be reviewed by EPA senior management as appropriate. An options
selection meeting (at which EPA management will select among alternative
options) for these issues is expected to be necessary by August 1988.
The regulatory program developed by EPA will take its place among a
complex variety of existing Federal and State programs that currently regulate
the mining industry (see Section 4.2 for brief descriptions of these pro-
grams). For this reason, the EPA program must be designed to complement, and
if necessary to extend, existing programs and authorities. A detailed
examination of existing programs (see Section 2.2.1.5) is being conducted in
order to allow the Subtitle D program to be sufficiently flexible to minimize
potential overlaps and conflicts. The Subtitle D regulatory program specific
to mining wastes is scheduled to begin Red Border review by January 1989.
Proposal of the program is currently scheduled for April 1989.
1.3.2 Outline of Key Tasks for Second Report to Congress
The second Section 8002 study on certain processing wastes (i.e., wastes
from the production of aluminum, copper, lead, and zinc) will rely on avail-
able data. Technical memoranda based on existing data will support the
report. A draft of the report to Congress will be submitted to EPA for review
on August 25, 1987, and the final Workgroup meeting on the report will be in
September. The draft report will be submitted to the Steering Committee in
October for reviews by EPA Management (Red Border review) and by the Office of
Management and Budget. The final report is to be submitted to Congress on
January 25, 1988. No later than July 25, 1988 (i.e., within six months after
submission to Congress), EPA is scheduled to publish a determination on which,
if any, of the processing wastes in the second report should be regulated as
hazardous under Subtitle C. Those wastes not regulated under Subtitle C will
be regulated under the Subtitle D program developed under this Management
Plan.
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An effort to determine the scope of the Bevill exclusion (i.e., which
wastes may not be regulated under Subtitle C before a study under Section
8002, a report to Congress, and a regulatory determination have been com-
pleted), is now underway, with particular concern for certain processing
wastes. In some cases, for example, it is not clear whether wastes from
particular mining industry practices would qualify as "processing" (i.e.,
smelting or refining) wastes under the Bevill exclusion. In other cases, it
is not clear whether the exclusion covers wastes that are produced by a
process that does not itself deal with ores or minerals, but that is asso-
ciated with smelting or refining processes. (Sections 4.5.3.3 and 4.5.3.4
describe this issue in more detail.) The Agency's interpretation of the
Bevill "boundaries" will be prepared for inclusion as a chapter in the second
report to Congress.
1.3.3 Outline of Key Tasks for Third Report to Congress
Initial efforts for this task are focused on determining the scope of the
study and report (i.e., identifying those industry segments and wastes, not
covered in previous reports, that are most likely to pose potential risks).
Scoping efforts consist of reviewing available data, additional data collec-
tion and surveys as necessary, and risk screening. Scoping is scheduled to be
completed in January 1988. (A listing of the mining wastes proposed for study
in the third report will be included in the second report.) Once the scope of
the third report has been determined, data collection activities in the
relevant industry segments will result in information adequate to satisfy
Section 8002, prepare a report to Congress, and make a regulatory determi-
nation on which, if any,' of the wastes should be regulated under Subtitle C.
The current schedule requires completion of data collection by July 1988,
submission of the final report to Congress by January 25, 1989, and publica-
tion of the regulatory determination by July 25, 1989.
1.4 OVERVIEW OF PROJECT MANAGEMENT AND STAFFING
As the preceding sections show, the development of a new regulatory
structure and two separate reports to Congress will be a complex task. Given
the relatively short time over which these tasks must be completed and the
relative scarcity of information on certain wastes and their environmental
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June 22, 1987
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L/834-052-00d/#20
impacts, numerous organizations and individuals will be involved and/or
interested in the overall process and the results. Consequently, a well-
designed organizational structure for accomplishing the various tasks must be
provided. This section presents an overview of that structure.
Figure 1-3 depicts the organizational framework for conducting the
activities described in this Management Plan. The two Project Directors for
this effort are Dan Derkics, the Chief of the Large Volume Waste Section in
the Office of Solid Waste (OSV), and Robert Valline, the Mining Waste Team
Leader in Region 8. Mr. Derkics will report to Truett DeGeare, the Chief of
OSW's Special Wastes Branch, and Mr. Valline will report to Jeffery Denit, the
Deputy Director of OSW. Figure 1-4 illustrates the management framework for
the regulatory development process.
Among Mr. Derkics' responsibilities will be to chair the Mining Waste
Regulatory Development Workgroup (see Section 3.1.2). In this position, he
will be responsible for ensuring that Workgroup members are fully informed of
all activities and are provided with an opportunity to comment on all activi-
ties and options under consideration. Mr. Derkics also has the primary
responsibility for ensuring that interim deadlines are met and that sufficient
progress is achieved to enable critical milestones to be met. Mr. Walline is
directing technical efforts in support of the regulatory development process.
In addition, Mr. Walline has the responsibility of chairing the External
Communication Committee (see Section 3.2). In this role, Mr. Walline is
responsible for maintaining and coordinating communications with all
interested parties.
Most Agency personnel with specific responsibilities for project tasks
are either in the Large Volume Waste Section of OSW or are Region 8 staff
members. Other EPA project staff include personnel from other OSW organiza-
tional units as well as from the Office of Policy, Planning, and Evaluation;
Office of Research and Development; Office of General Counsel; Office of
Congressional Liaison; Office of Water; and the Office of Air and Radiation
(see Section 3.1.2 for a full listing of Workgroup members). A total of 7.8
full-time equivalents (FTEs) are expected to be assigned to the project, 5.8
FTEs at Headquarters and 2.0 in Region 8. The fiscal year 1987 budget is
$2,200,000.
1-11
June 22, 1987
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Regulatory Development Workgroup
Project Directors
Oan Oerkics. Chief
Rob Walline, Mining Waste
Large Volume Wastes Section
Team Leader, Region 8
Chair. Regulatory
Chair. External
Development Workgroup
Communications Committee
Subtitle D Regulatory Development
External Communications Committee
Project Staff
Second Report to Congress
EPA STAFF
CONTRACTORS STAFF
Harry Stumpf (OSWI
Scott Mernitz (CDMI
EPA Lead
Tech. Pioj Mgr.
Cliff Rothenstein (OSW)
Data Mgt. System
Reg. Impact Anal.
Larry Buc (ICFl
O. Manin/O. Hicks
Risk Methodology
Cong. Communications
Jack Mozingo (SAIC)
Jack Hubbard IOROI
Policy/Program Support
WAM. PEI
Patty Fuller (CDMI
Gene Taylor IReg. 81
CERCLA Site Info.
CERCLA Data Comp.
Marty Holmes (CDMI
Matt Straus (OSW)
3007 Survey
Stds. and Criteria
Roger Olsen (CDMI
Paul Osborne IReg. 81
Technical Issues
Hydrol. Issues
Wendy Sydow (CDMI
Meg Silver (OGCI
Fed./State Prog. Review
Legal Issues
Model State Program
To be Assigned (OERR)
S. Mernitz/L. Brown
RCRA/CERCLA Issues
(CDMI
Reg. Support Doc.
Bob Hoye IPEII
Au/Ag Leaching Study
EPA STAFF
Ben Haynes (OSW)
EPA Lead
Smelting/Refining Issues
Scoping for Third RTC
Norm Huey (Reg. 8)
Technical Issues
B. Haynes/N. Huey
Bevill Amend Issues
Gene Taylor (Reg. 8)
CERCLA Data Comp.
Cliff Rothenstein (OSW)
Risk Assessment
Economic Impacts
Meg Silver (OGCI
Legal Issues
CONTRACTOR STAFF
David Bauer (ICFl
Project Mgr.
Scott Mernitz (COM)
Tech. Support Mgr.
Jack Mozingo (SAIC)
Policy/Program Support
Larry Buc (ICF)
Risk Assessment
Jens Deichmann (CDM)
Bevill Amend. Issues
Wendy Sydow (CDM)
Fed./State Prog. Review
S. Mernitz/John Hopkins
Scoping for Third RTC
Other Studies:
Bureau of Mines
Industry
Others
Third Report to Congress
EPA STAFF
CONTRACTOR STAFF
Ben Haynos (OSWI
Scott Mernitz (CDMI
EPA Lead
Tech. Proj. Mgr.
Smelting/Refining Issues
Jack Mozingo (SAICI
Scoping
Policy/Program Support
Cliff Rothenstein
John Hopkins (CDMI
Risk/Cost Analyses
3007 Survey
Gene Taylor (Reg. 8)
Industry Studies/Scoping
CERCLA Data Comp.
Wendy Sydow (CDMI
Meg Silver IOSC)
Fed./State Prog. Review
Legal Issues
FIGURE 1-3. Project Management and Staffing
-------
Figure 1-4. Management Structure for Mining Waste Regulatory Development
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K/834-052-00d/#20
Three separate firms are also assisting in the effort. Camp Dresser &
McKee (CDM) is the prime contractor for technical support and for the third
report to Congress. ICF Incorporated is responsible for the second report to
Congress and for risk, screening. Science Applications International
Corporation (SAIC) is providing program management and policy support. The
listing in Figure 1-3 of EPA and contractor personnel responsible for separate
tasks is not exhaustive. It does, however, list most of the primary partici-
pants in the process. Chapter 2 further describes the tasks and deliverables
for which EPA and contractor personnel are responsible.
1.5 MANAGEMENT PLAN ORGANIZATION
The remaining chapters of the Management Plan are summarized briefly
below. Each chapter is intended to be self-contained. The remainder of the
Management Plan is organized as follows:
Chapter 2. Major Activities in Regulatory Development Process
This chapter describes each of the major activities to be under-
taken and the projected schedules of completion.
Chapter 3. Communications Strategy
This chapter describes the communications strategy to be used to
ensure a constant flow of information among all interested and
involved parties. It describes the EPA Regulatory Development
Workgroup as well as agencies and organizations outside EPA that
will be involved in, or are interested in, the progress of
regulatory development.
Chapter 4. Regulatory and Technical Background, Approach, Issues and Data
Collection Needs
This chapter provides a detailed history of EPA's past activities
concerning mining waste and brief descriptions of existing
Federal and State programs that involve mining. It describes
technical and preliminary policy issues that will guide data
collection, and relates those issues to the specific data
collection activities described in Chapter 2. This chapter will
be revised and supplemented over time as issues are resolved and
additional issues and options are identified and developed.
Appendices. Technical Issue Papers
Nine technical issue papers are presented as Appendices A
through I. These issue papers describe critical areas of
interest, assess available information, and describe data gaps.
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CHAPTER 2
MAJOR ACTIVITIES IN REGULATORY DEVELOPMENT PROCESS
Page
2.1 PURPOSE 2-1
2.2 SUBTITLE D REGULATORY DEVELOPMENT 2-1
2.2.1 Data Compilation, Collection, and Evaluation 2-1
2.2.1.1 Summary and Evaluation of Existing
Information and Creation of Data
Management System 2-3
2.2.1.2 Compilation and Review of CERCLA Site
Information 2-5
2.2.1.3 Development of Technical Issue Papers... 2-5
2.2.1.4 Site Visits 2-6
2.2.1.5 Review of Federal and State Programs.... 2-7
2.2.1.6 Develop and Conduct Section 3007
Survey(s) 2-8
2.2.1.7 Risk. Screening Methodology 2-9
2.2.1.8 Focused Data Collection: Specific
Studies and Modeling Activities 2-9
2.2.2 Regulatory Development Activities 2-10
2.2.2.1 Development of Issues and Options 2-10
2.2.2.2 Model State Program. 2-11
2.2.2.3 "Straw Man" Regulatory Program 2-12
2.2.2.4 Regulatory Impact Analysis 2-12
2.2.2.5 Regulatory Support Document 2-12
2.2.2.6 Development and Proposal of Subtitle D
Regulatory Program 2-13
2.3 SECOND REPORT TO CONGRESS 2-14
2.3.1 Identification of Bevill Boundaries 2-16
2.3.2 Compilation of Existing Information 2-16
2.3.3 Compilation of CERCLA Site Information 2-16
2.3.4 Compilation of Information from 1984
Section 3007 Survey 2-17
2.3.5 Risk Assessment 2-17
2.3.6 Review of Existing Federal and State Programs.... 2-17
2.3.7 Scoping for Third Report to Congress 2-18
2.3.8 Report Preparation, Review, and Submission 2-18
2.3.9 Regulatory Determination 2-18
2.4 THIRD REPORT TO CONGRESS 2-20
2.4.1 Determining the Scope of the Report 2-20
2.4.2 Data Compilation and Collection 2-22
June 22, 1987
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B/834-052-00e/#7
CHAPTER 2
MAJOR ACTIVITIES IN REGULATORY DEVELOPMENT PROCESS (Continued)
Page
2.4.2.1 Compilation of Existing Information 2-22
2.4.2.2 Compilation of CERCLA Site Information.. 2-22
2.4.2.3 Primary Data Collection 2-22
2.4.2.4 Section 3007 Survey 2-22
2.4.3 Report Preparation, Review, and Submission 2-22
2.4.4 Regulatory Determination 2-23
June 22, 1987
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J/834-052-00f/#2
CHAPTER 2
MAJOR ACTIVITIES IN REGULATORY DEVELOPMENT PROCESS
2.1 PURPOSE
This chapter provides descriptions of the major activities to be under-
taken in support of the regulatory development process and projected schedules
for completion of each. Activities are described in three major sections that
correspond to the overall regulatory development process and to the second and
third reports to Congress, respectively.
2.2 SUBTITLE D REGULATORY DEVELOPMENT
The Subtitle D regulations are scheduled to be proposed in the Federal
Register on April 30, 1989. These proposed regulations will cover the
extraction and beneficiation wastes addressed in the December 1985 Report to
Congress, and the processing vastes from the second report to Congress that
are determined not to be appropriate for regulation under Subtitle C (see
Section 2.3 below). The initial regulatory program is not intended to cover
any of the wastes to be addressed in the third report to Congress (see Section
2.4).
Mr, Dan Derkics (OSV) has the overall Agency lead for completing the
Subtitle D regulatory development process for mining vastes. The major
activities involved in the process are shown in Table 2-1. The efforts needed
to complete the remaining milestones in Table 2-1 are divided into two major
areas. These areas and the EPA lead persons for each are:
Data Compilation, Collection, and Evaluation (Walline)
Regulatory Program Development Activities (Derkics)
These efforts are discussed separately in the following subsections.
2.2.1 Data Compilation, Collection, and Evaluation
CDM is the lead contractor for most data compilation and collection
activities; however, it is anticipated that some data will be collected by
ICF, PEIT and other contractors. Rob Walline (EPA, Region 8) is the Agency
2-1
June 22, 1987
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TAULX 2-1. HAJOB ACTIVITIES FOR SUBTITIaK D REGULATORY DEVELOPMENT
Ac 11 v 11 y
1987 1988 1989
JFHAMJJASOND JfMAHJJASOND JFHAHJ J
Start Action Bequest 2169
Regulatory Development Plio
lUoaqewot Plan
| DF (April 1)
| d-o (June 15)-
Subtttle 0 Regulatory Developaent
Data Compilation, Collection, and
Evaluation
Summaiy of existing inforaation
and Creation of data management
system
Compilation of CERCLA site
infotmat ion
Technical issue papers development
Development of protocols and methods/
Site visits
Review of Federal*' and State programs
Section 3007 survey
Risk screening methodology
Focused data collection; Specific
studies and modeling activities
Regulatory Development Activities
Development of issues and options/
Options selection meeting
Hodel State program
"Straw man" regulatory program
Draft regulatory program
Red Border/OMB reviews
Publication of proposed program
I-
Phase I-
-DMS-
CN/Leaching|
-l
-Develop | Reviews 1 1 Results-1
1
?Flow model
Workgroup Meetings
o o ooo o o o oo
OO
tforkgroup Reports to Steering
Committee
ooo
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J/834-052-00f/#2
lead person for these activities; other staff members from Region 8, the
Office of Research and Development in Cincinnati, and the Office of Solid
Waste (OSW) at Headquarters are or will be assigned to particular components
of the overall data collection efforts. The data compilation, collection, and
evaluation efforts, and the contractor(s) responsible for each, include:
Summary and analysis of existing information, Creation of data
management system (CDM)
Review of CERCLA site information (CDM)
Development of technical issues papers (CDM)
Site visits (CDM)
Review of Federal and State programs (CDM)
t Develop and conduct Section 3007 survey(s) (CDM)
Risk screening of relevant industry segments and wastes (ICF)
Other specific studies and modeling activities (CDM, PEI, BuMines,
industry, others)
Many of the data collection activities that are described below are
divided into two phases. Phase I efforts generally are aimed at assessing-
current information, identifying data needs, and planning future data col-
lection activities. Phase II efforts are anticipated to involve the actual
collection of data and the use of the data in regulatory development. Phase I
activities are underway at the present time and the products and schedules of
these activities are generally well-defined. Phase II activities should begin
in late 1987; since the scope and direction of many of these activities will
be based on the results of currently ongoing Phase I efforts, products and
schedules for many Phase II activities can be described only in general terms.
Each activity is described separately in the following subsections.
2.2.1.1 Summary and Analysis of Existing Information and Creation of Data
Management System
This task involves the review of a large number of reports that were
prepared for the Agency as well as numerous other data and reports produced by
and for other Federal and State agencies and the mining industry. CDM is
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June 22, 1987
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compiling and evaluating the data on a wide range of issues, including
industry segments, technical issues described in Section 2.2.1.3, waste
characterization, waste management practices, costs, and other related
matters.
The first step in this activity, obtaining copies of available EPA
reports and information, has largely been completed. The second step, which
is currently underway, involves collection of much additional data from
industry, other agencies, environmental groups, and others. It also involves
assessing each data source in terms of several categories (e.g., industry
segment, waste characterization, management practices). This step involves
the subtasks of identifying each category or "keyword" for which each data
source contains information, evaluating that data in terms of quantity and
quality, and listing data by category.
A computerized data management system is being created based on the first
subtask in this second step. This computerized system will contain entries
for each data source and will indicate what types of information (i.e., what
categories) are found in each source. This subtask should be completed by
late July 1987, at which time EPA will receive a file that lists existing data
sources and a characterization of which categories of information they
contain. At that time, the list of categories (keywords) by which information
is classified may be refined. A decision may also be made to expand the data
management system to contain the actual data for some of the keyword cate-
gories (e.g., actual waste sampling data) and/or to classify each category of
information as to its quantity and quality. The sheer size and complexity of
such a database would make such an expansion a major undertaking.
The data management system will be used not only for currently available
information, but will be continually updated as new information is collected
or is otherwise identified or becomes available. For example, the reports and
data from the data collection activities described in succeeding subsections
will be represented with appropriate entries in the system. The evaluation of
existing information and the data management system will be extremely valuable
throughout the regulatory development process. For example, data collection
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June 22, 1987
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J/834052OOf/#2
activities may be planned more efficiently by targeting areas where informa-
tion is in short supply or is of uncertain quality. The system will also
provide critical support to regulatory development efforts (e.g., issues and
options development, regulatory determinations, and the Regulatory Impact
Analysis) by allowing quick identification of the sources of particular types
of information (and perhaps the content and quality of the information).
2.2.1.2 Compilation of CERCLA Site Information
CDM is currently compiling Agency CERCLA site information on mining waste
sites. This information is intended to support the second and third reports
to Congress specifically (see Sections 2.3.2 and 2.4.2.2 below), and the
regulatory development process generally. Underway at present is the prepara-
tion of summaries on the approximately 40 mining waste sites on the proposed
or final National Priorities List (i.e., Superfund sites). To avoid over-
loading EPA Region staff members who are assembling the CERCLA information,
efforts have been concentrated on sites in processing industry segments being
addressed in the second'report to Congress (aluminum, copper, lead, and zinc).
Several 30- to 50-page summaries on processing sites already have been been
prepared and delivered; reports on processing sites for the second report to
Congress should be complete by late June, and compilation of data and comple-
tion of similar summaries for all mining waste sites are anticipated by
August 1987. Once all CERCLA mining waste sites have been summarized,
Phase II activities will involve another review of the information, with an
emphasis more on technical issues (e.g., control technologies, remediation).
An issue that is being considered in the compilation of CERCLA informa-
tion for the reports to Congress and the regulatory development is the use of
"enforcement confidential" data. Certain data will be releasable only at some
later date. Thus, all data must be qualified as to whether (and when) it can
be released.
2.2.1.3 Development of Technical Issue Papers
CDM is currently developing a series of nine technical issue papers. The
papers cover the following subjects:
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Acid Generation
Mobile Toxic Constituents-Water
Mobile Toxic Constituents-Air
Radioactivity
Asbestos
Cyanide
Direct Human Contact and Misuse
« Catastrophic Failure
Common Technical Issues.
These technical issue papers present EPA's definition of mining vaste
problems and issues that can affect human health and the environment. They
describe current knowledge on the problems and issues and discuss how they can
be modeled and controlled. Based on the information necessary for development
of a Subtitle D regulatory program, these papers also identify key data gaps.
Summaries of these technical issue papers are presented in Section 4.3.2; the
papers themselves are included as Appendices A through I. Each of the issue
papers will be reviewed by the Workgroup, the Department of the Interior's
Bureau of Mines, and by the External Communications Committee (see Section
3.2), and will be revised as necessary. The final papers are expected to
highlight further data needs and to assist in developing a consensus of
opinion on further data collection and regulatory development activities.
2.2.1.4 Site Visits
Visits to mining (i.e., extraction, beneficiation, and/or processing)
sites in order to collect information on design, operation, wastes, and waste
management are expected to be critical components in the regulatory develop-
ment process. CDM may conduct up to 9 site visits during Phase I and current
plans call for CDM to conduct up to 50 site visits during Phase II.
Phase I activities primarily involve the development of methods and
protocols to be used for the Phase II site visits. Should any Phase I site
visits be made, they will be designed to satisfy specific data requirements
and to assess and verify methods and protocols. Based on Phase I site visit
activities, the technical issue papers (see Section 2.2.1.3 above), and risk
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screening (see Section 2.2.1.7 below), a "straw man" site visit report will be
prepared by August 1987; this report will describe the methods and protocols,
including quality assurance and quality control procedures, that will govern
Phase II site visits. Because all raining waste sites (including about 300
active sites) cannot be visited, the selection of sites for data collection
will be critical. Preliminary site selection for Phase II site visits is
anticipated by August 1987, with additional sites to be selected as data
requirements are identified (e.g., through scoping for the third report to
Congresssee Section 2.3.7).
Phase II site visits will be designed to collect detailed information on
specific mining operations, including their design, operating characteristics,
waste characteristics and management practices, and other topics. Each visit
is anticipated to be made by a team of 3 to A people and to last 2 to 3 days.
Phase II site visits also may include one or more detailed case studies,
conducted by a larger team over 1 to 2 weeks. Phase II site visits may begin
as early as October 1987, and should be completed by July 1988.
2.2.1.5 Review of Federal and State Programs
Because the Agency has committed itself to developing a Subtitle D mining
waste program that will complement existing Federal and State programs, a
thorough knowledge of those programs is essential. To accomplish this, a
comprehensive review of State and Federal regulatory programs is being
conducted by CDM. The review is being undertaken with the following overall
objectives:
Identify effective components of existing programs for possible
inclusion in the Subtitle D program
Determine the capacity of States for implementation of a Federal
oversight program
Identify implementation problems associated with particular regulation
strategies at the State level
Consider alternative implementation strategies for a Federal program
that could be integrated into existing State organizations
Develop a model State regulatory program made up of components of
existing State programs selected for their particular strengths or
effectiveness (see Section 2.2.2.2).
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Phase I efforts are focusing on collecting data, compiling State-by-State
summaries, and sending the summaries to the States to be checked for accuracy
and completeness. States vith significant aluminum, lead, copper, or zinc
processing are being studied first to allow preparation of a section for the
second report to Congress. Completion of 3- to 5-page summaries for all
States with significant mining-related activity is scheduled for August 1987.
After review by EPA, the summaries will be sent to the States for review and
comment in August. Visits to selected States may be conducted during July and
August to collect information needed to fill data gaps and to initiate the
program evaluation, which will be principally a Phase II effort and will be
completed by June 1988. The final State summaries will be included in the
dra.ft regulatory support document in September 1987. Summaries of Federal
programs, also scheduled for completion in draft form by August 1987, will be
reviewed by the appropriate Federal agencies. (See Section 4.2.2 for brief
descriptions of existing Federal and State programs.) Although the authority
of the Office of Surface Mining Reclamation and Enforcement (OSMRE) extends
only to coal mining and its resultant surface effects, OSMRE programs will
also be examined.
During Phase II, a comparative analysis of the various State programs
will be conducted to develop a model State regulatory program. The model
program will comprise components of different programs and will serve as a
model in development of the Federal program. As described in Section 2.2.2.2,
the format and purpose of the model State program will be more specifically
defined at the completion of Phase I.
2.2.1.6 Develop and Conduct Section 3007 Survey(s)
At least two surveys conducted under the authority of RCRA Section 3007
are being planned to collect information from active mining operations. Two
surveys are currently being developed: one is intended to be primarily a
census of the industry (described here); another is intended to address
industry segments covered in the third report to Congress (described in
Section 2.4.2.4). Phase I involves the preparation of the survey instruments.
Phase II will involve distribution of the surveys to operators and the
analysis of information of completed surveys.
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The "census" survey will address active operations in the industry
segments addressed in the first report to Congress (i.e., extraction and
beneficiation of metals and certain nonmetals), with particular concern for
combined sites (i.e., sites where extraction, beneficiation, and processing
activities all occur). The precise scope of the questionnaire and the
questions are currently being developed by CDM and will be submitted to EPA in
July 1987.
The draft "census" survey questionnaire is scheduled to be submitted to
the Office of Management and Budget (OHB) by the late summer or early fall of
1987. 0MB review, questionnaire revision, and printing of the final question-
naire are expected to take at least A to 6 months. Distribution of the
questionnaire to mining operations then will occur in early 1988, with results
becoming available by June 1988.
2.2.1.7 Risk Screening Methodology
ICF is supporting the regulatory development effort by revising and
implementing a risk screening methodology. The major purposes of the risk
screening are to identify areas where additional data are required, identify
priorities for data collection, provide information for the regulatory impact
analysis, and suggest regulatory priorities for mining industry segments and
wastes. Of particular importance is the identification of waste and waste
management factors that most influence the potential risk to human health and
the environment. The initial results of ICF's risk screening methodology are
due in August 1987. Revisions to the screening methodology will be based on
reviews by the Workgroup and the Science Advisory Board. The results of the
risk screening also will be made available to interested parties through the
External Communications Committee.
2.2.1.8 Focused Data Collection: Specific Studies and Modeling Activities
Several studies to address particular data needs and issues, including
issues identified in the technical issues papers (see Section 2.2.1.3 and
Appendices) already have been undertaken, are currently being planned, or will
be planned. For example, PEI is developing a test plan for collecting
additional information on the characterization of gold and silver heap leach
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residue (see Section 4.3.1 for a description of heap leaching). Of particular
interest will be information on the content and fate of cyanides in the
residue. Current activities include the formation of a Peer Review Panel for
overview and technical input, defining the objectives of the waste character-
ization test plan, selecting test sites, and developing a methodology. Once
these activities are completed (by July 30, 1987), the test plan will be
implemented and waste characterization studies will proceed. Separate reports
will be prepared for each of an estimated four sites as well as a summary
report on all sites. The studies and all reports are scheduled to be com-
pleted by September 30, 1987.
Other government agencies and the mining industry will be instrumental in
commissioning and conducting certain studies. The Bureau of Mines and the
mining industry are planning to develop a subsurface flow model for heap
leaching. The results of the PEI study will be used as a source term for the
model that will be developed to predict the fate of leachates in various
hydrogeologic settings. Preliminary studies suggest the ability to develop a
model that accounts for attenuation, unsaturated flow, and neutralization of
leaching residues in addition to the saturated flow velocity parameters that
are found in current hydrogeologic transport models. Mr. Walline (EPA,
Region 8) is a member of the steering committee that will oversee this effort,
which is to be funded by the Bureau of Mines, industry, and possibly other
sources.
As the evaluation of existing data proceeds (see Sections 2.2.1.1 through
2.2.1.3) and data gaps are identified, additional studies may be necessary.
These will be commissioned and conducted as appropriate.
2.2.2 Regulatory Development Activities
2.2.2.1 Development of Issues and Options
SAIC is the lead contractor for the preparation of regulatory options
papers. This responsibility will include identifying and assigning priorities
to issues and options for presentation to the Workgroup; analyzing the
strengths and weaknesses of issues and options; incorporating comments from
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Workgroup members and outside groups; and preparing at least draft and final
options package to be reviewed by senior management in an options selection
meeting.
CDM vill assist in the development and analyses of issues and options by
providing technical data and technical options papers for use in determining
the strengths and weaknesses of various regulatory options. CDM also vill
review and provide comments on lists of issues, priorities of issues, and
regulatory options papers. ICF will assist in the development and analyses of
issues and options by applying risk screening models to various wastes,
facility locations, and waste management techniques.
A list of preliminary concepts and issues (including those described in
Section 4.5) will be prepared by late August for Workgroup and senior manage-
ment review. Major sources of data in the development of issues and concepts
will be the Phase I activities described in Section 2.2.1 above. Candidate
issues will be those that require relatively rapid resolution in order for
regulatory development to proceed and for which adequate data are available.
An options selection meeting is projected for late summer 1988. Issues
to be addressed will include all major issues not resolved previously. From
candidate issues and options, the issues and options for the options paper
will be selected. Based on comments made by Workgroup members and others, a
draft of the first options paper will be prepared by late May or June 1988 for
review by the Workgroup and others. After further review and revision, the
draft options selection package will be submitted to the Steering Committee by
late August 1988.
2.2.2.2 Model State Program
Based on the review of State regulatory programs described in Section
2.2.1.5, CDM will prepare a model State program report. The precise nature of
this report will be developed as the program review proceeds. The report
could describe, by industry segment and/or waste management practice, the
various regulatory approaches and programs used by States; it could describe
one or more exemplary approaches; or it could suggest or recommend an approach
for the Subtitle D program based on one or more State approaches. Once
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summaries of the State programs are prepared (by September 1987), evaluation
of programs will occur and the design of the model State program report will
be addressed. The model State program report is scheduled to be completed by
the spring of 1988.
2.2.2.3 "Straw Man" Regulatory Program
One means of generating external participation in the regulatory develop-
ment process that will be discussed by the Workgroup is the use of a "straw
man" regulatory package. As envisioned, this would involve the development
and distribution to the External Communications Committee (see Section 3.2) of
a package that includes one possible approach to the regulatory program.
Providing a concrete example of a regulatory program and soliciting comment,
rather than simply presenting general issues and approaches for discussion,
should make interested parties more willing to express their concerns. These
comments in turn would be extremely valuable in developing a program that
meets the broadest possible acceptance. As the regulatory development process
continues, the issue of developing such a "straw man" program will be
discussed; if the approach is adopted, the package would be made available to
interested parties by the fall of 1988.
2.2.2.k Regulatory Impact Analysis
Cliff Rothenstein (OSW) has the EPA lead for completing the risk and cost
impact analyses that are required for all major rulemakings. ICF is the lead
contractor in these efforts. These efforts began with the development of the
risk screening methodology, described in Section 2.2.1.7, and the preliminary
cost data that appeared in the December 1985 Report to Congress. These
initial efforts will be greatly expanded by the additional data to be col-
lected over the next year. Comprehensive baseline risk and cost models should
be developed by the spring of 1988. These models will be used to evaluate
differences between the major alternative regulatory approaches. The risk and
cost models will be refined during the summer of 1988, and will be finalized
for Workgroup closure in December 1988.
2.2.2.5 Regulatory Support Document
To support the regulatory program being developed, CDM will prepare draft
and final versions of a Regulatory Support Document (RSD). This document will
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present the results of all the data compilation and collection activities
described in Section 2.2.1 above. The draft RSD, which will describe Phase I
activities, is to be completed in the fall of 1987. The final RSD, covering
Phase II activities, is scheduled for submission in September 1988.
2.2.2.6 Development and Proposal of Subtitle D Regulatory Program
As stated by the Agency in the initial commitment to design a regulatory
program under Subtitle D that is specific to mining wastes (51 FR 24496;
July 3, 1986), current plans call for a program that consists of a tailored
risk-based approach that addresses the unique concerns of mining waste. To
the extent possible, the requirements of the program will address the tech-
nical feasibility, environmental necessity, and economic practicality of
controls.
As described in Chapter 1, the initial program will cover the extraction
and beneficiation wastes addressed in the first report to Congress and any
processing wastes addressed in the second report to Congress (see Section 2.3
below) that are determined not to be appropriate for regulation under Subtitle
C. The program will be designed with sufficient flexibility to allow addi-
tional mining wastes to be covered in the future (e.g., wastes addressed in
the third report to Congress that are determined not to be appropriate for
regulation under Subtitle C, and perhaps other wastes that have not been
addressed in a report to Congress).
EPA initially stated its hope that the program would be developed by
"mid-1988." The complexity of the issues involved, the amount of data
collection that will be necessary, and other factors have resulted in the
current schedule, which calls for the regulatory program to be proposed in
April 1989. The factors responsible for the current schedule include:
The need to address all potential release pathways (e.g., many
individual sites have the potential for more than one of the environ-
mental problems described as technical issues in Section 4.3.2 and
appendices; in addition, the same or similar environmental problems
can occur in several different industry segments)
The necessity to evaluate existing waste characterization methods and.
the possible need to develop and/or adopt new ones
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The inclusion of processing wastes from four industry segments in the
Subtitle D program (at the time of the determination to develop a
Subtitle D program specific to mining waste, EPA had proposed to
exclude most processing wastes from the Bevill exclusion)
The necessity of communicating and cooperating with many interested
parties, including Congress and other Federal agencies
The need to collect additional data to support development of the
regulatory program and the Regulatory Impact Analysis.
2.3 SECOND REPORT TO CONGRESS
As described in Chapter 1, the second Section 8002 study and report to
Congress will address processing wastes in selected industry segments
(segments include aluminum, copper, lead, and zinc). The study and report
will be based on existing information. ICF is the lead contractor for study
and report completion, with CDM also providing support. Table 2-2 presents
the major activities involved in completing the Section 8002 study and the
report to Congress.
The major work efforts undertaken by the two contractors are:
Identifying wastes that are conditionally excluded from Subtitle C
regulation by the Bevill Amendment (CDM)
t Compiling existing information (ICF)
Compiling CERCLA site information (CDM)
.Compiling information from a previous Section 3007 survey (ICF)
Preparing risk-assessment information (ICF)
Reviewing existing programs in States where the industry segments are
concentrated (CDM)
Scoping for the third report to Congress (CDM/ICF)
Report preparation and submission (ICF/CDM)
Regulatory determination (ICF).
The following subsections describe each of these activities.
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TAB LB 2-2. HAJOB ACTlVIflES rOB SECCMH) UPOIT TO CONCUSS
1987 1986 1989
Activity
S«cood Btpoit to Congress
(oa s«l«cta4 processing |*
N) Scoping tor third export to Con^ctss
»¦
Report Preparation, Rtvuw, and
Submission |
Coapi 1 At ion of existing data | 1
Prtpiiition of technical Miounda | 1
Identification of Bevill boundaries |D~f
Compilation of CERCLA sita
information | 1
Coapilation of information from
1984 Section 3007 survey | 1
Risk assessment | o
Review of existing Federal and
State programs |
Draft report o (Aug. 2S)
Bed Border/OHB reviews | )
Pinal report submitted to Congress o (Jan. 25)
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J/834-052-00f/#2
2.3.1 Identification of Bevill Boundaries
As described in Chapter 1, the Bevill amendment excludes from Subtitle C
regulation all wastes from the "extraction, beneficiation, and processing" of
ores and minerals until Section 8002 studies and reports to Congress have been
completed. EPA has interpreted this exclusion as applying to waste from the
"exploration, mining, milling, smelting, and refining of ores and minerals"
(45 FR 76118). However, there are certain industry practices that produce
wastes for which individual decisions have had to be made as to whether they
were included within the Bevill "boundaries" and thus excluded from Subtitle C
regulation. For example, many industry segments, in processing ores and
minerals, generate or use the products of associated co-located processes that
do not themselves use ores and minerals (e.g., ammonia production, acid
plants). (This issue is addressed in more detail in Section 4.5.3.3.)
EPA has had to make numerous decisions since 1980 as to whether specific
wastes were conditionally excluded from Subtitle C regulation, and these
decisions generally have been made on an ad hoc basis. To assist in resolving
the issue of the Bevill "boundaries" and to assist in future decisionmaking,
EPA's interpretation of the issue will be presented as a chapter of the second
report to Congress. CDM has prepared a draft of an interpretation of the
Bevill "boundaries" for review by the Agency. After approval of a final
draft, a chapter for the second report to Congress will be prepared and
included in the draft report.
2.3.2 Compilation of Existing Information
ICF is the lead contractor in this effort and has compiled data from a
number of sources, including reports prepared for EPA in the past. Data have
been submitted to the Bureau of Mines and industry for verification by late
June. Technical memoranda describing and presenting these data should be
complete by mid-July and will support the report to Congress.
2.3.3 Compilation of CERCLA Site Information
As described in Section 2.2.1.2, CDM is currently compiling CERCLA
information on mining waste sites in the industry segments being addressed in
the second report to Congress. Summary reports on 3 of the more than 10 sites
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have already been prepared, and preparation of the remaining reports should be
complete by late June 1987. This information will be useful in describing
specific management practices and their consequent effects on human health and
the environment.
2.3.4 Compilation of Information from 1984 Section 3007 Survey
ICF has recently obtained data from a Section 3007 survey of smelting and
refining operations completed in 1984. Data on processing operations of
concern have been submitted to the Bureau of Mines for review and comment.
Based on this review, the information will be revised and presented in the
draft technical memoranda and the draft report to Congress.
2.3.5 Risk Assessment
ICF has developed a computerized risk screening model, which consists of
a number of linked submodels designed to provide information on the overall
risks between and within mining segments and to identify additional data that
may be needed to refine the risk screening and assessment processes. The
model includes four major components (source terms, transport and fate,
exposure, and risk), each requiring different sets of input data such as waste
types, waste volumes, management methods, and climatological data. ICF is
coordinating with CDM to obtain sufficient data to run the risk model. The
results from the risk assessment model will be provided in the relevant
sections of the draft and final report to Congress.
2.3.6 Review of Existing Federal and State Programs
As part of CDM's State and Federal program review described in Section
2.2.1.5, States with significant aluminum, lead, copper, or zinc processing
will be studied for development of a section on applicable State and Federal
regulations for the second report to Congress. This section will address the
range of regulations with which facilities that dispose of processing wastes
from these sectors must comply. The draft section will be submitted to ICF by
June 30, 1987 and submitted with the rest of the draft report to Congress to
EPA on August 25, 1987. The section will be revised as appropriate based on
EPA comments and possibly additiona-l data gathering efforts.
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2.3.7 Scoping for Third Report to Congress
In order to allow public comment on the Agency's decision on what
industry segments and wastes should be addressed in the third report to
Congress, a section will be included in the second report that announces EPA's
intentions (see Section 2.3.7). The industry segments to be considered are
those listed in Table 2-3. The decision on which segments to address will be
based on the volume, contaminants, and potential risks those segments' wastes
are estimated to pose; estimates will be based on the risk screening
accomplished by that time. (See Section 2.4.1.)
2.3.8 Report Preparation, Review, and Submission
The first draft of the second report to Congress is to be submitted on
August 25, 1987, for review by Project Directors and others. After being
revised based on reviews by the Workgroup and others, a final Workgroup
meeting on the report will be held in late September. The report then will be
submitted to the Steering Committee for review, followed by Red Border
(beginning in late October) and Office of Management and Budget (beginning in
late November) reviews. Submission to Congress of the final report is
scheduled to occur by January 25, 1988.
2.3.9 Regulatory Determination
The decision to regulate under Subtitle C any mining wastes studied under
Section 8002 must be made within 6 months of the submission of a report to
Congress on the results of such a study. The regulatory determination on
which, if any, of the processing wastes addressed in the second report to
Congress will be made as soon as possible (i.e., by July 25, 1988). If any of
the wastes are determined not to be appropriate for regulation under
Subtitle C, they will be covered by the Subtitle D regulatory program being
developed. The regulatory determination as to the appropriate program under
which "second report wastes" should be regulated will be based on the areas
studied under Section 8002: annual sources and volumes of waste generated;
current disposal and utilization practices and alternatives; potential risk to
human health and the environment; the cost of alternative disposal practices;
and the impact of alternative practices on natural resource use.
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TABLE 2-3. INDUSTRY SEGMENTS UNDER CONSIDERATION
FOR INCLUSION IN THIRD REPORT TO CONGRESS
Metal
Nonmetal
Antimony
Arsenic
Beryllium
Bismuth
Cadmium
Cesium
Chromium
Cobalt
Gallium
Germanium
Gold
Indium
Iron
Magnesium
Manganese
Mercury
Molybdenum
Nickel
Niobium
Platinum Group Metals
Rare Earth Metals
Rhenium
Rubidium
Scandium
Selenium
Silver
Strontium
Tantalum
Tellurium
Thorium
Tin
Titanium
Titanium Oxide
Tungsten
Vanadium
Zirconium/Hafnium
Asbestos
Barite
Bituminous Materials
Boron and Borates
Bromine
Clays
Coke/Synfuels
Diatomite
Feldspar
Fluorspar
Garnet
Gemstone
Glauconite
Gypsum
Iodine
Kyani te
Lime
Limestones
Lithium
Mica
Olivine
Peat
Perlite
Phosphate
Potash
Pumice
Pyrophyllite
Salt (Halite)
Sand and Gravel
Silica and Silicon
Shale
Sodium Sulfate
Staurolite
Stone
Talc
Tripoli
Trona
Vermiculi te
Wollastonite
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2.4 THIRD REPORT TO CONGRESS
The following major activities are planned for the preparation of the
third report to Congress. Each activity is described in separate subsections
below. Table 2-4 presents the schedules for these activities.
Determining the scope of the report (i.e., identifying the industry
segments and wastes to be addressed)
Data collection:
- Compilation and evaluation of existing information
- Compilation of CERCLA site information on relevant industry
segments
- Section 3007 survey
- Primary data collection (review of State/Federal programs, site
visits)
Report preparation, review and submission
Regulatory determination.
2.4.1 Determining the Scope of the Report
CDM is preparing screening papers on industry segments that may be
included in the third report to Congress for potential regulation under
Subtitle C, Subtitle D, or otherwise. Each paper will provide a general
description of an industry segment, including geographic distribution,
process, and waste characteristics. Any wastes generated that may have
adverse impacts on human health or the environment will be identified, and a
qualitative assessment of waste volumes and possible hazards will be included.
The papers will be reviewed by the Bureau of Mines and EPA and then presented
to the External Communications Committee for comment. These screening papers
on industry segments will provide the basis for identifying industry and
wastes to be addressed in the third report to Congress. (See Section 2.3.7
above for the means by which the scoping decision will be presented for public
review and comment.)
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TAOU 2-4. HAJOR ACTIVITIES FOR TUIRO ISMBT TO CQBGBSSS
Activity
1987 1988 1969
JPMANJJASONO JFMAMJJASOND J F H A M J J
Third Report to Congress
Scoping
Screening studies on industry
segments
Data conpilation and collection
Compilation of e&isting date
Compilation of CERCLA site
inforaation
Pnaftry data collection
Section 3007 industry survey
Report preparation,
submission
4, and
Draft report
Red Border/OMB Reviews
Pinal report submitted to
Congress
Regulatory determination
| Phase I 1-
-Phase 11^
|-Develop|-Reviews |-
-|Results-|
o (Aug. 25)
o (Jan. 25)
(July 25)
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J/834052-00f/#2
2.4.2 Data Compilation and Collection
2.4.2.1 Compilation of Existing Information
Data compilation and evaluation for the overall regulatory development
process is described in Section 2.2.1.1; compilation and evaluation for this
report to Congress (i.e., for the industry segments and wastes to be
addressed) are a subset of activities described in that section.
2.4.2.2 Compilation of CERCLA Site Information
Compilation of CERCLA site information for all mining waste sites on the
proposed or final National Priorities List is described in Section 2.2.1.2;
activity relevant to this report to Congress will involve examining site data
for industry segments and wastes that are selected for this report.
2.4.2.3 Primary Data Collection
This will involve reviews of State and Federal programs in States where
the industry segments being addressed are concentrated as well as visits to
mining industry sites for data collection. These activities are described in
Sections 2.4.1.4 and 2.4.1.5.
2.4.2.4 Section 3007 Survey
CDM is developing a survey instrument to be used to collect information
from mining industry sites in the industry segments that are candidates for
the third report to Congress. As with the Section 3007 survey described in
Section 2.2.1.6, EPA and Office of Management and Budget reviews are scheduled
for the early fall of 1987. The survey should be distributed late in 1987,
with results available by March of 1988.
2.4.3 Report Preparation, Review, and Submission
The schedule calls for the first draft of the third report to Congress to
be submitted for review by August 25, 1988. After being revised based on
reviews by the Workgroup and others, a final Workgroup meeting on the report
will be held in late September. The report then will be submitted to the
Steering Committee for review, followed by Red Border (beginning in late
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October) and Office of Management and Budget (beginning in late November)
reviews. Submission to Congress of the final report is scheduled to occur by
January 25, 1989.
2.A.4 Regulatory Determination
As with mining wastes addressed in the second report to Congress, the
regulatory determination on which, if any, of the wastes that will be
addressed in the third report will be made as soon as possible (i.e., by
July 25, 1989). The regulatory determination of whether any "third report
wastes" should be regulated under Subtitle C will be based on the areas
studied under RCRA Section 8002: annual sources and volumes of wastes
generated; current disposal and utilization practices and alternatives;
potential risk to human health and the environment; the cost of alternative
disposal practices; and the impacts of alternative practices on natural
resource use.
Any "third report wastes" determined not to be appropriate for
Subtitle C regulation would (by default) fall under Subtitle D, as described
in Chapter 1. However, the Subtitle D program that will be proposed in April
1989 (see Section 2.2) will not initially cover these "third report wastes"
(for which the regulatory determination will not occur before July 1989).
Rather, it may be necessary to amend the new Subtitle D program to include
these (and perhaps other wastes not addressed in a report to Congress) at a
later date.
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CHAPTER 3
COMMUNICATIONS STRATEGY
Page
3.1 INTERNAL COMMUNICATIONS 3-1
3.1.1 Agency Offices with Significant Involvement 3-1
3.1.2 Mining Vaste Regulatory Development Workgroup.... 3-4
3.1.3 Steering Committee 3-7
3.2 EXTERNAL COMMUNICATIONS 3-8
3.3 CONGRESSIONAL COMMUNICATIONS 3-10
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CHAPTER 3
COMMUNICATIONS STRATEGY
This chapter defines the communications strategy that the Office of Solid
Waste (OSU) will follow throughout the regulatory development process. The
intense interest shown by numerous parties (including other Federal agencies,
the Congress, States, industry, and public interest organizations) makes the
communications strategy critical to the success of the regulatory program
being developed. This chapter is divided into three subsections, corres-
ponding to the three major communication efforts necessary for the program:
Internal Communications
External Communications
Congressional Communications
An overview of the communications strategy is illustrated in Figure 3-1.
3.1 INTERNAL COMMUNICATIONS
3.1.1 Agency Offices with Significant Involvement
Within EPA, several offices have an interest in the progress of the
mining vaste reports and regulations. These offices are included in the
Mining Waste Regulatory Development Workgroup (see Section 3.1.2). The roles
and concerns of a feu key EPA offices are described below.
Office of Emergency and Remedial Response (OERR): EPA has published its
intent to apply CERCLA authorities to address releases from mining sites
that may pose substantial threats and imminent hazards. In response to
the Superfund Amendments and Reauthorization Act of 1986, the Hazard
Ranking System (HRS) is being revised so it more accurately reflects the
character of wastes at mining sites (see Section 4.3.1). "Case study"
data on the environmental effects of mining wastes are being gathered
from CERCLA files in support of both regulatory and report development.
OERR Workgroup representatives will keep the Workgroup informed (through
briefings or memoranda) on the specific adjustments that are being made
to the HRS and how these adjustments may affect the rulemaking process.
In addition, OERR Workgroup representatives willassist the Workgroup in
understanding present and future Agency policies for establishing cleanup
levels at mining sites on the NPL.
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FIGURE 3-1. OVERVIEW OF COMMUNICATIONS STRATEGY
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Office of External Affairs (PEA): This rulemaking will require input
from two offices within OEA: the Office of Congressional Liaison (OCL)
and the Office of Legislative Analysis (OLA). These offices will ensure
that timely and efficient contacts are made with the appropriate con-
gressional staff members. The representatives from OCL and OLA will
assist the Workgroup in describing to congressional staffers the types of
additional enforcement and permitting authorities that are needed to
support the new Subtitle D rules for the mining industry. In addition,
OCL and OLA will assist the Workgroup in informing congressional staffers
and receiving their comments on EPA activities and decisions on the
mining waste regulations. The Office of Solid Waste/ Office of Policy
Planning Information (OSW/OPPI) will also be involved, in the course of
RCRA reauthorization discussions, in the effort to notify Congress of any
needed statutory changes.
Office of Waste Programs Enforcement (OWPE): The Subtitle D regulatory
program for mining wastes will be implemented and enforced by the States.
Therefore, the Workgroup will require assistance from OWPE to identify
regulatory options that are compatible with existing State programs and
resources. OWPE will assist the Workgroup in developing regulatory
options that will result in strong, enforceable regulations and elimi-
nating those options that will be difficult for States to implement and
enforce. OWPE also will inform the Workgroup on the Agency's solid waste
enforcement policies and procedures, and relative costs and legal
difficulties associated with different regulatory approaches.
Office of Research and Development (ORD); This organization has spon-
sored many of the past studies on mining operations, practices, and waste
characterization. ORD's historic knowledge and present/future studies
should be fully coordinated with OSW actions. ORD is currently funding a
study on the waste characteristics of dumps and heaps in the gold and
silver mining segments (Section 2.2.1.8). ORD will keep the Workgroup
informed of the findings of this and any future study that they sponsor
in regard to mining wastes.
EPA Regions: Mining is concentrated in a few EPA Regions, although all
Regions contain facilities subject to the rulemaking. Efforts will be
coordinated with experts resident in the Regions and all Regions are
encouraged to participate in Workgroup discussions.
Office of Water (OW): Under the Clean Water Act, EPA regulates the
discharge of contaminants from point sources. Nonpoint sources emanating
from mining sites are also a widespread concern (e.g., acid mine drain-
age). OW may also be interested in environmental criteria benchmarks
used in any risk assessments (e.g., water quality, sediment criteria, and
ground-water classification). Representatives from OW will assist the
Workgroup by providing clear descriptions of water quality problems at
mining sites and EPA's current policies for protecting ground and surface
waters at mine sites.
Office of Air and Radiation (OAR): The rulemaking process will involve
decisions on acceptable levels and appropriate controls for airborne
constituents and radiation at mining operations. OAR will assist the
Workgroup in developing mining waste regulations that are protective of
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human health and the environment and consistent with ongoing programs
within OAR.
Office of General Counsel (OGC): All rulemaking activities at the Agency
must be reviewed by OGC to ensure legally defensible rules that are
consistent with statutory authorities and previous legal decisions made
by the Agency. In addition, two lawsuits have been filed in response to
EPA actions that bear on this rulemaking effort. One of the lawsuits
challenges EPA's July 3, 1986 decision (51 FR 24496) to regulate the
extraction and beneficiation wastes in the December 1985 Report to
Congress under Subtitle D rather than Subtitle C of RCRA. The outcome of
this lawsuit could alter, delay, or even end the rulemaking. The other
lawsuit challenges EPA's October 9, 1986 (51 FR 36233) decision to
withdraw its October 2, 1985 (FR 50 40292) proposal to narrow the Bevill
exclusion and to regulate under Subtitle C six processing wastes. The
outcome of these lawsuits may affect the schedule and resources for
preparation of the reports to Congress.
Office of Policy, Planning, and Evaluation/Office of Policy Analysis
(0PPE/0PA): This office Is involved in all major rulemaking activities
at the Agency. This office will contribute to the selection of appro-
priate issues for options selections meetings under this rulemaking. In
addition, OPA will help ensure that the Workgroup explores all viable
options for each issue by drawing on the types of options being pursued
in other rulemaking activities throughout the Agency. OPA's involvement
in the direction of other current rulemaking activities will be a
valuable resource for the Workgroup in ensuring that the Agency's
policies are developed interactively and consistently with developing
policies in other Agency offices.
Office of Drinking Water (ODW); Any potential releases of constituents
from mining operations to ground water or surface water must be analyzed
to determine its impact on drinking water in the affected area. ODW will
assist in the rulemaking process by participating in decisions on safe
concentrations of various constituents in potential drinking water
supplies. In addition, the office includes the Underground Injection
Control (UIC) program, which should be involved in decisions on _ln situ
mining issues.
3.1.2 Mining Waste Regulatory Development Workgroup
The Mining Waste Regulatory Development Workgroup is chaired by
Dan Derkics, Chief of the Large Volume Waste Section in OSW's Special Wastes
Branch. The Workgroup is composed of a number of representatives from OSW
(the lead EPA office for this rulemaking), other EPA offices, and key Federal
agencies and departments (see list of Workgroup membership below). The
Workgroup is responsible for making informed decisions that result in a viable
and effective mining waste rule. Workgroup participants will review all data
and all decisions resulting from rulemaking activities on mining wastes and
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vithin their own offices. These reviews will lead to prompt oral or written
notifications to the Workgroup Chairman when policies or procedures within a
representatives' office are, or appear to be, directly related to or in
conflict with the developing regulations. Each Workgroup representative will
inform the Workgroup about the underlying performance standards and theories
behind all regulations within his or her office, and explaining how these
standards and theories are similar to or different from those being considered
under the mining regulatory framework. Workgroup members will review the list
of issues and options that are developed during the course of the Workgroup
meetings and offer alternative issues and options until satisfied that all
potentially viable issues and options have been considered. Finally, each
Workgroup member will keep the appropriate staff within his/her office
informed (preferably with memos after each Workgroup meeting) on the status of
all issues, options, and regulatory approaches being considered by the
Workgroup and contribute to resolving all issues. Each representative will
also elicit comments from office staff for presentation to the Workgroup
Chairman in a timely manner.
Workgroup meetings will be held when major products become available
(e.g., draft reports to Congress, State and Federal program reviews, risk
screening methodology, and the results of other activitiessee Chapter 2),
when issues arise that require Workgroup discussion or resolution, and when
decisions that require Workgroup input are to be made. The most recent
Workgroup meeting was held on February 24 for the purpose of reviewing the
Regulatory Development Plan. The next meeting, to review this Management
Plan, is planned for July 9. Workgroup meetings will be held approximately
every 4 to 6 weeks during the development process. The Workgroup chairman
will schedule meetings as the need arises and Workgroup members will receive
an agenda for meetings, together with copies of documents or lists of issues
to be discussed, 1 to 2 weeks prior to the scheduled date. Workgroup members
will review the items/topics to be discussed from the perspective of their
respective offices and at meetings will represent the policy positions of
their management.
The U.S. Department of the Interior also has established an internal
working group on the mining waste regulatory development. Concerns of various
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Interior offices and bureaus are expressed in this group, and in turn are
brought before the EPA Workgroup by Workgroup members Jon Stone and Michael
Kaas, both with the Bureau of Mines. In addition, Mr. Stone is providing one
third of his professional hours to assist EPA in resolving technical issues
and understanding current policies within various offices within Interior.
EPA Workgroup Members:
Dan Derkics, Chairman
Truett DeGeare
Harry Stumpf
Ben Haynes
Elizabeth LaPointe
Susan Absher
Cliff Rothenstein
Frank Smith
Ron Burke
Matt Straus
Marlene Berg
Phil Jalbert
Lynn Delpire
Jim Doherty
Meg Silver
Patrick Cummins
Dave Levy
Rick Westlund
Yvonne Weber
Terrance McLaughlin
Jack Russell
Kirt Cox
Francoise Brasier
Bob Thronson
Bill Telliard
Matt Jarrett
Steve Bugbee
Jack Hubbard
OSWER/OSW/SWB (Office of Solid Waste and
Emergency Response, Office of Solid Waste,
Special Waste Branch)
OSWER/OSW/SWB
OSWER/OSW/SWB
OSWER/OSW/SWB
OSWER/AA (Office of the Assistant
Administrator)
OSWER/OSW/SPB (State Program Branch)
OSWER/OSW/EAS (Economic Analysis Section)
OSWER/OSW/EAS
OSWER/OSW/EAS
OSWER/OSW
OSWER/OERR/HSCD (Hazardous Site Control
Division)
OSWER/OERR/PAS (Policy Analysis Section)
OPTS/OTS (Office of Pesticides and Toxic
Substances, Office of Toxic Substances)
OECM (Office of Enforcement and Compliance
Monitoring)
OGC (Office of General Counsel)
OPPE/OPA (Office of Policy, Planning and
Evaluation; Office of Policy Analysis)
OPPE/OSR (Office of Standards and
Regulations)
OPPE/OSR/IPB (Information Policy Branch)
OEA/OFA (Office of External Affairs, Office
of Federal Activities)
OAR/ORP (Office of Air and Radiation, Office
of Radiation Programs)
OAR/ORP
OAR/OAQPS (Office of Air and Radiation;
Office of Air Quality Planning and
Standards; Research Triangle Park NC)
OW/ODW (Office of Water, Office of Drinking
Water)
OW/CSD/NPSB (Compliance and Standards
Division, Non-Point Source Branch)
OW/ITD (Industrial Technology Division)
OW/ITD
OW/PD (Permits Division)
ORD (Office of Research and Development,
Cincinnati OH)
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Brian Burgess
Rob Walline (ECC Chairman)
Ray Corey
Paul Day
Non-EPA Workgroup Members:
Jon P. Stone
L. Michael Kaas
Scott Boyce
Rick Deery
David Stonfer
David Cammarota
Norm Day
Region 6 (Dallas TX)
Region 8 (Denver CO)
Region 9 (San Francisco CA)
Region 10 (Seattle VA)
U.S. Department of the Interior, Bureau of
Mines
U.S. Department of the Interior, Bureau of
Mines
U.S. Department of the Interior, Bureau of
Land Management
U.S. Department of the Interior, Bureau of
Land Management
U.S. Department of Commerce, International
Trade Administration
U.S. Department of Commerce, International
Trade Administration
U.S. Department of Agriculture, Forest
Service
Other Federal agencies invited to participate in the regulatory process:
U.S. Department of Energy
U.S. Trade Representative.
3.1.3 Steering Committee
The Workgroup reports periodically to a Steering Committee, which is
EPA's standing body for regulatory oversight and which consists of repre-
sentatives of the Assistant Administrators, the General Counsel and Regional
Regulatory Contacts. The Steering Committee has two primary objectives: to
help program offices plan regulatory activities and to aid the Workgroup in
ensuring issues, particularly cross-media issues, are raised and resolved at
appropriate levels of management. The Steering Committee also directs the
movement of regulatory documents through the Agency's regulatory review
system. The Steering Committee will ensure that all significant issues are
identified and resolved before the proposed rule and the reports to Congress
are submitted for EPA Red Border review and Office of Management and Budget
(0MB) review. Red Border is the formal mechanism by which EPA senior manage-
ment (usually Assistant and Regional Administrators and the General Counsel)
reviews and approves regulatory packages (including reports to Congress)
before they are presented to the Administrator. The Workgroup, with Steering
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Committee oversight, defines and resolves all significant issues so that no
new issues or problems arise during Red Border review. Executive Order 12291
requires that all proposed and final rules (including reports to Congress) to
be issued by the Agency must be reviewed by the Office of Management and
Budget (0MB). This review is intended to ensure that agencies (within the
constraints of statutory requirements) choose among the various alternatives
by considering the costs and benefits associated with each.
The first Workgroup report to the Steering Committee, on the draft
Regulatory Development Plan, was reviewed at the March 18 Committee meeting.
The next report, on the draft second report to Congress, will be in
September 1987.
3.2 EXTERNAL COMMUNICATIONS
The Subtitle D program for mining wastes has generated unusually wide
interest, and brief descriptions of interested parties are provided below.
Mining Industry. There has been a general economic decline in most
mining industry segment activities in the recent past. Any regulation
that may impose additional costs on the industry is certain to undergo
close scrutiny. The industry has expressed its interest in participating
in the regulatory development process (or at least being kept apprised of
developments) and representatives of some industry segments have pledged
to cooperate in EPA's data collection efforts. In addition, industry
groups have initiated two studies and have proposed a third (see Section
2.2.1.8). Small mining operators have also expressed their strong
interest in having their concerns taken into consideration.
Public Interest Organizations. Several environmental organizations and
other public interest groups have also expressed their interest in Agency
activities concerning mining waste. Site-specific problems at several
mining industry sites (e.g., CERCLA sites, certain smelters) have
received significant attention from public interest groups and have thus
generated interest in the Agency's activities concerning mining wastes.
Environmental groups have challenged certain EPA positions on mining
waste issues and will continue their oversight activities. (At least two
Agency positions are currently being challenged: the regulatory deter-
mination to regulate extraction and beneficiation wastes under Subtitle D
rather than Subtitle C and the Agency's withdrawal of its proposed
reinterpretation of the Bevill exclusionsee Section A.2.)
States. State governments are concerned with the environmental damages
associated with mining sites and the financial and societal costs asso-
ciated with any regulations designed to mitigate damages. Another area
of interest to the States is the relationship between any EPA-developed
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program and existing State programs. Other areas of particular concern
will be the means of implementation of any new program and the possible
availability of Federal funding.
Other Federal Agencies. A number of Federal agencies have regulatory
responsibilities that deal directly or indirectly with mining waste
issues. The U.S. Department of the Interior's Bureau of Mines has an
interest in the health and productivity of the mining sector. The U.S.
Department of Agriculture's Forest Service and Interior's Bureau of Land
Management and National Park Service currently regulate mining activities
on Federal lands under their control. They have expressed a strong
interest in any Agency actions concerning mining waste. The U.S.
Department of Commerce and the International Trade Representative have
also expressed an interest.
An outreach program has been initiated to foster the participation of
external parties in the development of the regulatory program. An External
Communications Committee (ECC), chaired by Rob Walline of Region 8, has been
formed to organize this activity. The ECC consists of several Workgroup
members and other Federal representatives who will meet regularly with repre-
sentatives of States, public interest groups, industry, and Federal agencies
not otherwise involved in the regulatory development (see Figure 3-1).
A preliminary meeting of the ECC on December 12, 1986, drew over 100
participants. Because of the difficulty of coordinating and receiving
representative participation from such large constituencies, a smaller group
consisting of selected representatives of State regulatory agencies, industry,
and public interest groups will be used to convey comments and recommendations
of their respective constituencies to the ECC. For example, at the pre-
liminary meeting of the ECC, representatives of Trout Unlimited agreed to
coordinate involvement of other environmental and public interest organiza-
tions (the Environmental Defense Fund has also been invited to participate and
the League of Women Voters also may participate in the process). Most ECC
meetings will be held in Denver (which is relatively centrally located insofar
as mining activity can be said to be centralized); additional meetings may be
held in other locations as appropriate.
The next meeting of the ECC will be held in July to discuss this
Management Plan. The preliminary regulatory issues (described in Section 4.5)
and the technical issue papers (summarized in Section 4.3.2 and presented in
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full as Appendices A through I) are expected to receive particular attention.
The Project Directors will schedule future ECC meetings as appropriate (e.g.,
when information from outside parties is necessary, when major decisions are
to be made, and when major milestones are reached). To ensure that external
comments are integrated into the development process, Workgroup members will
participate in ECC meetings and summaries of ECC comments and concerns will be
provided to the Workgroup.
3.3 CONGRESSIONAL COMMUNICATIONS
Congressional representatives from States with mining activities have a
strong interest in environmental damages at mining sites, the economic impact
of any regulatory program, and the potential for future environmental damages.
In addition, EPA has expressed its concern (51 FR 24496; July 8, 1986) that
the current lack of Federal oversight and enforcement authority under
Subtitle D could jeopardize the effectiveness of any mining waste regulatory
program that may be developed. To ensure that any program developed will be
effective, EPA also has expressed its intent to work with Congress to develop
the necessary authority.
As deliberations on a regulatory approach evolves, EPA staff (Debora
Martin of the Office of Policy Planning Information and Diane Hicks of the
Office of Congressional Liaison) will meet with congressional representatives
to brief them on activities and options. The Office of Legislative Analysis
also will be instrumental. Of particular concern are the need for oversight,
permitting, and enforcement mechanisms in Subtitle D; the ultimate regulatory
structure; and the definition of the Bevill "boundaries." In addition,
Congress will be interested in keeping apprised over the progress of various
studies. OPPI will arrange, through OCL, briefings of key Congressional staff
at key decision points in the process. Most recently, the RCRA Reauthoriza-
tion Task Force was briefed on mining waste issues by Rob Walline and
Dan Derkics on May 7, 1987. At the next meeting of the Task Force, in mid-
June, mining waste issues will also be discussed.
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CHAPTER 4
REGULATORY AND TECHNICAL BACKGROUND, APPROACH, ISSUES, AND
DATA COLLECTION NEEDS
Page
4.1 PURPOSE 4-1
4.2 STATUTORY AND REGULATORY BACKGROUND 4-1
4.2.1 RCRA Statutory and Regulatory Background 4-2
4.2.2 Other Federal Statutes and Programs 4-3
4.2.3 State Programs 4-7
4.3 TECHNICAL BACKGROUND 4-8
4.3.1 Types and Amounts of Mining Wastes 4-8
4.3.2 Technical Issues Summaries 4-12
4.3.2.1 Acid Generation 4-12
4.3.2.2 Mobile Toxic Constituents - Water 4-13
4.3.2.3 Mobile Toxic Constituents - Air 4-15
4.3.2.4 Radioactivity 4-16
4.3.2.5 Asbestos 4-17
4.3.2.6 Cyanide 4-19
4.3.2.7 Direct Human Contact and Misuse 4-20
4.3.2.8 Catastrophic Failure 4-21
4.3.2.9 Common Technical Issues 4-22
4.3.3 Descriptions of Mining Segments 4-25
4.3.3.1 Copper 4-25
4.3.3.2 Lead and Zinc 4-28
4.3.3.3 Gold and Silver 4-30
4.3.3.4 Uranium 4-32
4.3.3.5 Phosphate 4-33
4.3.3.6 Asbestos 4-34
4.3.3.7 Molybdenum 4-34
4.3.3.8 Aluminum 4-34
4.4 CONCEPTUAL PROGRAM DESIGN 4-35
4.5 PRELIMINARY REGULATORY DEVELOPMENT ISSUES 4-39
4.5.1 Issue 1: Overall Approach to the Rulemaking 4-41
4.5.1.1 Issue 1A: What Should be the Regulatory
Approach 4-42
4.5.1.2 Issue IB: How Should the Present
Administrative and Enforcement
Authorities under Subtitle D be Revised
for Mining Wastes? 4-44
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-OK u.j. ^/^vtRNMENT
USE ONLY
CHAPTER 4
REGULATORY AND TECHNICAL BACKGROUND, APPROACH, ISSUES, AND
DATA COLLECTION NEEDS (Continued)
Page
4.5.2 Issue 2: What Should be the Relationship Between
the Subtitle D Program and Existing
Regulatory Structures 4-45
4.5.3 Issue 3: Potential Scope of the Subtitle D
Program 4-46
4.5.3.1 Issue 3A: How should the Regulations
Apply to Abandoned, Inactive, New, and
Existing Facilities and Sites? 4-46
4.5.3.2 Issue 3B: What is the Relationship
Between RCRA and CERCLA Standards at
Mining Sites? 4-48
4.5.3.3 Issue 3C: What are the Boundaries of
the Bevill Exclusion at Processing
Facilities? 4-98
4.5.3.4 Issue 3D: What are the Regulatory
Distinctions Between Process Materials
and Wastes? 4-50
4.5.3.5 Issue 3E: How should Waste Management
Controls be Applied to Combined
Extraction, Beneficiation, and
Processing Sites? 4-51
4.5.3.6 Issue 3F: Which Mining Segments
Should be Considered in Future Subtitle
D Rulemaking Efforts? 4-52
4.5.4 Issue 4: What Are the Technical Methodologies
and Standards Needed to Support the
Rulemaking? 4-53
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CHAPTER 4
REGULATORY AND TECHNICAL BACKGROUND, APPROACH, ISSUES
AND DATA COLLECTION NEEDS
4.1 PURPOSE
This chapter provides a brief overview of the statutory and regulatory
background and the technical basis for regulating mining waste under
Subtitle D of the Resource Conservation and Recovery Act (RCRA). It also
presents the initial regulatory and technical issues developed by the Agency
and discusses the need for additional data collection efforts to address these
issues. In meeting the objectives of this chapter:
Section 4.2 provides the RCRA statutory and regulatory background to
the mining waste issue and describes current regulation of mining
wastes by other Federal and State authorities.
Section 4.3 provides an overview of the Agency's current technical
knowledge and understanding of mining waste generation and management.
It describes the types and amounts of wastes generated by mining
operations, and presents the Agency's current understanding of several
critical technical issues. It also summarizes basic information on
several of the mining industry segments to be addressed in the current
rulemaking effort.
Section 4.4 summarizes a preliminary conceptual design for the
regulation of mining wastes under Subtitle D of RCRA. This design is
based on the technical background and issue summaries presented in
Section 4.3.
Section 4.5 summarizes the preliminary major regulatory issues and
discusses the need for additional data collection efforts.
4.2 STATUTORY AND REGULATORY BACKGROUND
This section describes the background for the Agency's determination to
develop and implement, under Subtitle D of RCRA, a regulatory program that is
designed specifically for mining wastes. Mining wastes are currently regu-
lated under several Federal and State laws; summaries of the relevant Federal
laws and examples of State regulations are also presented.
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4.2.1 RCRA Statutory Background
Section 8002(f) of 1976 RCRA directed EPA to produce a ". . . detailed
and comprehensive study on the adverse effects of solid wastes from active and
abandoned surface and underground mines on the environment. ..." Among
other amendments to RCRA in 1980, Congress added Section 8002(p), which
required EPA to prepare a report that would review "... the adverse effects
on human health and its environment, if any, of the disposal and utilization
of solid wastes from the extraction, beneficiation, and processing of ores and
minerals. ..." This report was to be developed concurrently with the
earlier mandated 8002(f) report. Further, Congress added Section 3001(b)(3)
(A)(ii), which provided that mining wastes could not be regulated as hazardous
until six months after the Section 8002 studies were completed and report(s)
to Congress were submitted. This amendment, known as the Bevill Amendment,
conditionally excludes (from regulation under Subtitle C) all wastes from the
"extraction, beneficiation, and processing of ores and minerals". EPA adopted
the statutory language of the exclusion into the regulations on November 19,
1980 (45 FR 76118). The preamble to the rule interpreted the exclusion to
include "solid waste from the exploration, mining, milling, smelting, and
refining of ores and minerals."
Nearly five years later, on August 21, 1985, the D.C. District Court [in
response to Concerned Citizens of Adamstovn et al. v. EPA, Civil No.
84-03-3041 (D.D.C.)] ordered EPA to complete the studies by June 30, 1986 and
to propose and take final action on a reinterpretation of the scope of the
mining waste exclusion by September 30, 1986. On October 2, 1985 (50 FR
40292), EPA proposed to reinterpret the mining waste exclusion so that
relatively few processing (i.e., smelting and refining) wastes were condi-
tionally excluded from Subtitle C regulation. In addition, the Agency
proposed to list as hazardous six wastes associated with smelting operations.
The proposed reinterpretation and the proposed listing were withdrawn on
October 9, 1986 (51 FR 36233) because there were inadequate criteria for
determining which processing wastes should be excluded.
On December 31, 1985, EPA submitted a Report to Congress on the results
of the first Section 8002 study: Wastes from the Extraction and Beneficiation
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of Metallic Ores, Phosphate Rock, Asbestos, Overburden from Uranium Mining,
and Oil Shale. On July 3, 1986 (51 FR 24496), EPA made a regulatory deter-
mination that the wastes addressed in the December 1985 Report to Congress
should be regulated under Subtitle D. It was concluded that Subtitle C
standards were "likely to be environmentally unnecessary, technically
infeasible, or economically impractical" if they were applied to mining
wastes. In addition, EPA concluded that it was uncertain whether a mining
waste program under Subtitle C could be flexible enough to address "the risks
presented by mining wastes while remaining sensitive to the unique practical
demands of mining operations." RCRA provides that solid waste that is not
subject to regulation under Subtitle C is subject to regulation under
Subtitle D. It was noted, however, that existing Subtitle D criteria, which
primarily address municipal and industrial solid waste, do not fully address
mining waste concerns and do not provide for Federal oversight or enforcement.
EPA stated the intent to develop a program under Subtitle D that would be
appropriate for mining wastes.
The July 3, 1986, regulatory determination and the October 9, 1986,
withdrawal of the proposed reinterpretation and listing have both been
challenged in court. Litigants' briefs are due by August 14, 1987, EPA's
briefs are due September 16, and oral arguments are scheduled to be heard
December 11, 1987.
4.2.2 Other Federal Statutes and Programs
Currently, mining and mining wastes are regulated under a variety of
Federal and State authorities. The manner in which the various regulatory
agencies administer existing programs, and the requirements of the various
programs, are known but not well documented for individual authorities and
programs, and relationships between programs are not well known. The extent
to which future plans have been made also is not well known. EPA will
therefore be compiling and analyzing information on these programs and their
relationships to help determine how best to structure the Subtitle D program
and how to coordinate the new program with existing State and Federal programs
(see Section 2.2.1.5). Although the authority of the Office of Surface Mining
Reclamation and Enforcement (OSMRE) extends only to the surface effects of
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coal mining, OSMRE programs will be analyzed as well. Brief descriptions of
major authorities and programs are provided below.
The Comprehensive Environmental Response, Compensation, and Liability Act
of 1980 (CERCLA) established the Superfund program to deal with releases and
potential releases of hazardous substances, including hazardous wastes. The
Superfund program ranks sites where releases have occurred, or where there is
a substantial threat of a release, using the Hazard Ranking System (HRS).
Sites scoring above a certain score using the HRS (i.e., those that pose the
most significant risks) are then included on the National Priorities List
(NPL). The Superfund Amendments and Reauthorization Act of 1986 (SARA) added
Subsection 105(g) to CERCLA. This subsection provides that, pending a
required revision of the HRS, EPA must consider certain factors before adding
"special, study waste" sites (which include mining waste sites) to the NPL.
Factors that must be considered include: (1) the extent to which the HRS
score is affected by special study wastes, and (2) available information on
the quantity, toxicity, and concentration of hazardous substances that are
constituents of the waste, potential for release, potential exposure from
release, and the degree of hazard posed by release. In general, Superfund is
intended to be a remedial, or reactive, program rather than a preventive
program.
The Mining Law of 1872, as amended, governs the prospecting and appro-
priation of metallic and most nonmetallic minerals (so-called "locatable" or
"hardrock" minerals) on Federal lands. It allows mining claims to be located
upon the discovery of valuable mineral deposits on Federal lands not withdrawn
from mineral entry (mineral entry is the filing of a claim for public land to
obtain the right to any minerals it may contain). Holders of valid claims
have exclusive rights to the land for mining purposes, and may mine and remove
minerals. If claimants meet certain requirements, they may purchase legal
title (patent) to the surface in addition to mineral rights on the claim.
The Mineral Leasing Act of 1920, as amended and supplemented, amended the
Mining Law of 1872 by creating a leasing system for coal, oil, oil shale, gas,
phosphate, and other fuel and chemical minerals on Federal lands (so-called
"leasable" minerals). Leases are issued by the Bureau of Land Management
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(BLM) after the terms under which development can take place are specified by
the appropriate land management agency.
The Federal Land Policy Management Act of 1976 (FLPMA) required all
holders of mining claims on Federal lands to record their mining claims with
BLM. BLM is responsible for managing the mineral resources under all Federal
lands and for managing the surface resources of BLM-managed lands. FLPMA also
authorized BLM to take necessary actions to prevent unnecessary or undue
degradation of BLM lands. BLM's regulations under FLPMA (43 CFR 3809) provide
for reclamation of lands disturbed by mining and define three levels of mining
operations: the first level, "casual use," applies to areas where mechanized
earthmoving equipment and explosives are not used; the second level applies to
surface disturbances of less than 5 acres per year; and the third level
applies to disturbances of over 5 acres per year. For operations in the
second level, operators must submit a letter or notice of intent; for opera-
tions in the third level, operators must submit a plan of operation that
describes the operation, including reclamation plans. Bonds are required when
an operator has a record of noncompliance.
Forest Service regulations under the Organic Administration Act of 1897,
as amended, (36 CFR 228 Subpart A) are intended to protect the surface
resources of National Forest System lands. The regulations require that a
"notice of intent to operate" must be submitted by operators proposing
prospecting or mining activities under the Mining Law of 1872, as amended,
that might cause disturbances of surface resources. A proposed plan of
operations is required if an operation would cause significant disturbance of
surface resources (i.e., if mechanized earthmoving equipment or explosives are
to be used). All operations must minimize adverse environmental impacts to
the extent feasible and must take into consideration Federal, State, and local
requirements concerning air and water quality among others. Reclamation bonds
may be required for operations likely to cause significant surface distur-
bance. In addition, the Forest Service plans to cross-reference provisions of
its regulations with certain sections of RCRA and CERCLA.
The National Park System is closed to mineral entry and development under
the Mining Law of 1872, as amended, except for claims make prior to 1976 in
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six units of the System (Death Valley and Organ Pipe National Monuments,
Glacier Bay and Denali National Parks and Preserves, Crater Lake National
Park, and Coronado National Memorial) and leases of minerals in five national
recreation areas (Lake Mead, Glen Canyon, Ross Lake, Lake Chelan, and
Whiskeytown-Shasta-Trinity). National Park Service (NPS) regulations
(36 CFR 9) are intended to prevent or minimize environmental and resource
damage. The regulations require mitigation of impacts (including impacts from
waste disposal), reclamation, and the posting of bonds. Unlike BLM and the
Forest Service, NPS has control over private property (including patented
claims) within its jurisdiction.
Point source discharges to surface waters from mining and mineral
processing facilities are regulated under the Federal Water Pollution Control
Act, as amended. These discharges require a permit under the National
Pollutant Discharge Elimination System (NPDES). NPDES permits place effluent
limitations and monitoring requirements on permitted discharges.
National ambient air quality standards set under the Clean Air Act (CAA)
apply to criteria pollutants, including particulates and lead, emitted by
mining and processing operations. Permits issued to point sources by EPA or
authorized States set emission limitations for these criteria pollutants.
Phosphosypsum wastes from phosphate processing are under review for CAA
control due to their radioactivity.
Under the Safe Drinking Water Act, all mine backfilling operations
(active mines and those undergoing closure) are regulated by rule as Class V
underground injection control (UIC) wells (backfilled mines are mines whose
voids are filled with mine waste). In situ oil shale and coal gasification
retorts and wells used for solution mining and conventional mines, such as
stope leaching, are also regulated as Class V wells. These activities are
regulated by rule and subject to inventory requirements and a general perfor-
mance standard which prohibits movement into underground sources of drinking
water (i.e., aquifers with total dissolved solids less than 10,000 rug/liter).
Injection that may result in a violation of primary drinking water regulations
may result in either a closure action or the facility may be required to
obtain a permit. Injection wells for in situ extraction of minerals such as
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copper, uranium, othermetals, sulfur, and salt are regulated as Class III
veils. Class III veils must be permitted, vith the permit stipulating certain
construction, operating, monitoring, and closure requirements to protect
underground sources of drinking vater.
Wastes from the beneficiation of uranium ores are regulated under the
Uranium Hill Tailings Radiation Control Act of 1978 (UMTRCA). These regula-
tions are administered by EPA and the Nuclear Regulatory Commission. Radio-
activity standards of 5 pCi per gram for solids and 50 pCi per liter for
liquids are applied as disposal and cleanup limits for these wastes. Wastes
from the processing of uranium ores are regulated by the Nuclear Regulatory
Commission under the Atomic Energy Act of 1954, as amended.
4.2.3 State Programs
The extent to which the various States regulate mining waste management
practices is extremely variable, both from state to State and, within indivi-
dual States, for different industry segments. Some States have minimal or no
regulatory requirements, while others have comprehensive and effective
programs in place. California and Wyoming, for example, have programs that
provide for the protection of all environmental media, including ground water.
Most of the more comprehensive State programs are relatively new or have
undergone extensive revision in recent years. Most States have permitting
requirements to control (or at least monitor) mine site development, opera-
tion, and reclamation. Several States also have developed programs to protect
ground water or address radioactive wastes. These States often require
postclosure maintenance and monitoring. Most States, however, do not require
postclosure monitoring; instead, reclamation bonds are released, usually when
a specified vegetative cover has been attained. In addition, many States
regulate mining operations through agencies with which EPA historically has
not had extensive dealings (e.g., many States have natural resource or mining
agencies that are separate from agencies that implement various EPA air and
water quality programs).
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4.3 TECHNICAL BACKGROUND
This section presents brief descriptions of the types and amounts of
wastes within the mining segments addressed in the December 1985 Report to
Congress. These descriptions are followed by a series of nine technical
issues summaries, vhich reflect the Agency's perspective on the pathways and
severity of environmental releases from mining operations. The final part of
this section presents background information on many of the mining industry
segments to be addressed in the current rulemaking.
This section will be periodically updated to add descriptions of the
types and amounts of wastes within the mining segments addressed in the second
Report to Congress (scheduled for submittal in November 1987), update the
technical issues summaries, and present background information on any other
mining industry segments that may be addressed in the current rulemaking.
4.3.1 Types and Amounts of Mining Wastes
There were approximately 300 active sites in 1984 in the mining industry
segments addressed in the December 1985 Report to Congress (which addressed
wastes from the extraction and beneficiation of metallic ores, uranium
overburden, asbestos, phosphate rock, and oil shale). Extraction and bene-
ficiation in these industry segments generated approximately 1.3 billion tons
of waste in 1982, with copper, iron, ore, uranium, and phosphate mining
operations responsible for over 85 percent of this amount.
Approximately 50 percent of this waste was mine waste (i.e., soil or rock
generated during the process of gaining access to the ore or mineral body).
Most mine waste was generated by phosphate, copper, iron ore, and uranium
mining. Over 55 percent of mine waste was disposed in onsite piles, 31
percent was used onsite in leaching operations (because heap/dump leaching is
considered to be a process, mine "waste" used for leaching is not considered
to be a waste until leaching operations are complete and the heap and dump are
abandoned), 9 percent was used for backfilling, and 4 percent was used offsite
(for construction and other purposes).
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Tailings (i.e., wastes generated by physical or chemical beneficiation
processes used to separate the metal or mineral from the host rock) con-
stituted approximately one-third of the wastes. Most tailings were generated
by the copper, phosphate, and iron ore segments. Over 60 percent was disposed
in onsite impoundments, 32 percent was used for onsite leaching operations (in
which case, again, the tailings are not considered to be a waste until the
leaching operations are complete), 5 percent was used for backfilling, and
2 percent was used offsite.
Approximately one-sixth of the wastes resulted from dump/heap leaching
processes. (Dump or heap leaching involves the placement of water, acid, or
cyanide-containing solutions onto sometimes enormous piles of material. The
liquid percolates through the pile and dissolves valuable metals, including
copper, gold, and/or silver. The "pregnant liquor," by then containing
dissolved metals, then is collected at the base of the pile and the metals are
recovered.) It should be noted that under RCRA, the pile, the liquid, and the
liquor are not considered to be wastes while the leaching process is in
operation. However, any liquid or liquor that escapes the process (e.g.,
liquor that escapes through the base of the pile rather than being collected)
is a waste, tfhen leaching operations end and the site is abandoned, any
remaining liquid and liquor, and the pile itself, also become wastes.
Mine water, the water that infiltrates mines during the extraction
process and must be removed for operations to continue, is also a waste
"generated" at many mine sites. Mine water may be collected in impoundments,
discharged directly to streams or other receiving waters, or handled in other
ways.
Of the approximately 1.3 billion tons of mining waste (i.e., mine waste,
tailings, heap/dump leaching wastes, and mine water) that were generated by
extraction and beneficiation in the industry segments addressed in the
December 1985 Report to Congress, over 800 million tons were potentially
hazardous (although it should be noted that current analytical procedures may
not be appropriate to determine the hazardousness of mining wastes). This
compares to less than about 300 million tons of wastes, produced by all other
industries combined, that were regulated as hazardous under Subtitle C. Of
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those 800 million tons, 61 million tons were estimated to be EP toxic or
corrosive; an estimated 23 million tons were contaminated with cyanide;
approximately 277 million tons were potentially acid-forming; about 443
million tons had radioactivity content over 5 picocuries per gram; and an
estimated 5 million tons had a chrysotile (asbestos) content over 5 percent.
Damage cases have shown that mine discharge, mine runoff, and seepage
have contaminated soils and surface and ground water at some sites. Short-
and long-term releases of cyanides, acids, and metals have reduced fish
populations and the numbers of other freshwater organisms. Airborne pol-
lutants (including asbestos and lead) from some sites also have presented a
hazard to human health. During short-term monitoring at a limited number of
sites, EPA detected seepage from tailings impoundments, a copper leach dump,
and a mine water pond. No migration of EP toxic metals was detected during
the 8-month period; however, other studies have detected contaminants.
Contamination of drinking water aquifers, degradation of aquatic ecosystems,
fish kills, and other environmental degradation all have been documented in
the phosphate, gold, silver, copper, lead, and uranium segments of the mining
industry. Analysis of damage cases and Superfund sites indicates that at
least some of the problems that have been experienced are attributable to
waste management practices not currently used. The ability of current
practices to avoid problems is not well-documented.
The size of the area affected by mining activities is controlled by
several factors, including the size of the mining operation, mining techniques
used at the site, characteristics of the ore and associated rocks and ambient
environmental characteristics such as hydrology and meteorology. Fundamental
activities in the extraction and beneficiation of ores are similar for many
segments of the mining industry (see Figure 4-1). A typical operation
includes: (1) removal of overburden and ore from the mine workings (under-
ground or open pit); (2) disposal of overburden (waste rock); (3) storage of
ore at the surface; (4) ore beneficiation (including leach processes and
conventional milling); and (5) disposal of beneficiation wastes (abandonment
of leach piles and tailings ponds or piles.
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ore and waste haulage
w^inine
dewatering
(low pH and
metals In
discharges)
high grade ore
cyanide and radioactivity
groundwater
fug
dust
J smelter II
^ psKr-J-AIl
itive ' *
ore concentrate
mill
runoff
^""~-sl^g A collected particulates
metals to
groundwater tailings pond
runoff "
/\
"*~ U O |
u
fugitive
dust, asbestos and to air
radioactivity
low pll and metals
to groundwater
dump leach operation
low pll and
metals to
groundwater
low pll, metals, cyanide and radioactivity
to groundwater
FIGURE A-i. TYPICAL MINING INDUSTRY SITE AND HASTES PRODUCED
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N/834-052-00e/#2
4.3.2 Technical Issues Summaries
The Agency has conducted a preliminary evaluation of the pathways and
potential environmental impacts of releases from mining waste within the
mining industry segments addressed in the December 1985 Report to Congress.
Technical issue papers have been prepared on each of the following nine major
issues:
Acid Generation
Mobile toxic constituents - water
Mobile toxic constituents - air
Radioactivity
Asbestos
Cyanide
Direct human contact and misuse
Catastrophic slope failure
Common technical issues.
For any of these technical issues to present a problem, three conditions
must be present. There must be a source of toxic materials, a pathway for
transport of these materials into the environment, and a receptor that is put
at risk from exposure to or ingestion of these contaminants. In these dis-
cussions, the source is some form of mining waste. Pathways may be air,
surface water, or ground water. Potential receptors include human popula-
tions, wildlife, aquatic organisms, or sensitive ecosystems. Management of
mining waste can avert a problem by treating the waste to eliminate or reduce
its toxicity or containing the waste so that it does not enter transport
pathways.
Summaries of the technical issue papers are presented in succeeding
subsections. Full texts of the papers appear as Appendices A through I.
4.3.2.1 Acid Generation
The mining and processing of metallic ores has resulted in the degrada-
tion of surface water and ground water supplies. One of the major causes of
this contamination is acid generation from the oxidation of sulfide bearing
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minerals, of which pyrite is the most significant. The sulfide mineral reacts
with water and oxygen in the presence of bacteria to produce sulfuric acid and
iron hydroxide or iron sulfate. The low pH values result in the dissolution
of minerals and the release of toxic metals and other constituents (e.g.,
sulfate).
The assessment of the problem and resultant management controls must be
site specific. Management controls may include pretreatment to eliminate the
source, containment, and/or controlled release with subsequent treatment.
Pretreatment techniques include plugging of mine adits (entrances) and burial
of waste below the water table. Both of these techniques prevent oxidation of
the sulfide minerals, thus eliminating the source. Containment techniques,
such as capping to eliminate infiltration, remove the transportation pathway.
Under all management scenarios, monitoring may be required to verify the
integrity of controls.
Although extensive data exist concerning environmental impacts associated
with mining of metallic ores, little has been done to integrate sources,
pathways, receptors, and potential risks. The following activities are
recommended to support technical understanding of the environmental impacts of
acid generation:
Integration of data necessary to evaluate potential impacts on human
health and the environment
Risk assessment methods for mining sites
Analytical techniques to predict acid generation potential
Techniques to predict leachate water quality.
4.3.2.2 Mobile Toxic Constituents - Water
During the mining and milling process, physical and chemical changes can
release toxic constituents to ground and surface waters. For example, when
metallic sulfide minerals are exposed to oxygen, water, and bacteria, the
minerals are oxidized and produce acid, resulting in the subsequent dissolu-
tion of metals and production of sulfate. Changes in oxidizing conditions can
also mobilize metals without the production of acid.
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Once the toxic constituents are released in the dissolved form, they can
be transported in ground vater and surface water. In these regimes, they may
undergo further reactions such as adsorption or precipitation. The exact
transport and fate of the constituents depend on site-specific factors. In
all cases, the exposure of receptor populations is a major concern. Evalu-
ation of potential exposure risk also requires site-specific information.
The analytical methods used to characterize ground water and surface
water constituents are veil established. However, many different techniques
are used to dissolve the solid samples and the solid portions of liquid
samples. These techniques range from total solubilization techniques to
bio-available techniques. Likewise, a large variety of leach tests exist to
determine the quantities of toxic constituents actually released from the
solid materials. Once the sources have been characterized, a variety of
impact prediction methodologies may be applied. Typically, geochemical and
hydrological computer models are used.
Management techniques used to eliminate or control the release of toxic
constituents to ground and surface waters vary widely. Options include
encapsulation/containment of tailings and waste rock, controlled release of
discharges, treatment of discharges, capture and return of discharges,
plugging of adits, and solidification of solids with alkaline materials. The
effectiveness of these management controls depends upon the site conditions
and potential pathways and receptors.
Consistent and standardized analytical procedures are needed to
characterize samples from mining sites. Procedures may include:
Techniques for crushing/grinding and sample preparation
Techniques for dissolving solid samples and the solid portion of
liquid samples
Tests to determine the quantity of metals leached from solid samples
Tests to determine the fate and transport of the dissolved metals in
ground water and surface water regimes.
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Dissolution techniques should include methods that simulate bio-available
concentrations and leaching under actual site conditions.
Once the toxic constituent source concentration is determined, the poten-
tial environmental impacts should be evaluated and predicted. Geochemical and
hydrological models may be used for this task. These models are strong
evaluation tools, but should be used in conjunction with professional judgment
to account for site-specific conditions.
Once the characterization techniques and prediction methodologies have
been determined and standardized, several sites should be evaluated using the
selected procedures.
4.3.2.3 Mobile Toxic Constituents - Air
Mining operations, both active and past, contribute to airborne toxic
constituents. Active mining operations release contaminated dust from mining,
smelting process, and waste disposal practices. Improper waste disposal at
past mining operations are sources o£ airborne toxic constituents.
Mining wastes and airborne emissions from facilities are cause for
concern when there are toxic contaminants, a pathway (in this case, air), and
a receptor population. Vaste characterization and air monitoring stations are
necessary to determine the potential for exposure to the receptor population.
Site-specific data must also be considered; for example, the location of the
waste piles and meteorological factors. Once the source concentrations,
pathways, and receptors are determined, risk assessment combined with basic
assumptions and site-specific data can be used to determine whether the
potential for adverse impacts exists.
Current regulations (Federal and State) assure that fugitive emissions
are controlled during processing operations. However, regulations regulating
nonprocess sources, such as waste piles or resuspension by vehicular activity,
are either not in effect or are not consistent from State to State. Regula-
tions may be required to address waste disposal, controls on waste, and
monitoring the effectiveness of the waste controls. Examples of controls on
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waste piles include, but are not limited to, wetting, chemical fixation,
enclosure, and physical stabilization. High volume air samplers located
between the waste source and the potential receptor population can be used to
monitor the adequacy of these controls.
Consistent regulations to prevent fugitive emissions from waste disposal
are recommended. In support of the regulatory process, the following
activities may be required:
Developing recommended controls on waste piles and verification of the
effectiveness of these controls (air sampling)
Modeling to predict potential airborne pathway releases
Risk, assessments to determine potential health effects.
4.3.2.4 Radioactivity
The uranium and phosphate mining industry segments produce the largest
volume of waste material of any of the industry segments. These wastes are
characterized by large volumes and low radioactivity. As described in Section
4.2.2, uranium mill tailings are currently regulated under the Uranium Mill
Tailings Radiation Control Act (UMTRCA). Radioactive uranium mining wastes,
as well as radioactive mining wastes generated from other mining sectors are
not currently regulated at the Federal level. The problem is complex since
some sites are located in relatively remote arid regions and some are located
in populated humid environments. Some sites pose a definite risk to human
health and the environment and other sites pose little or no threat. The
primary risk to human health and the environment from uranium and phosphate
mining waste is from radionuclides. The source radionuclides can exist as a
gas (radon), in solid matrices (waste rock), and as dissolved species in
water. Because of these various states, all pathways of transport must be
considered. In particular, air pathways, surface and ground water, and direct
contact pathways are important. Accumulations of radon gas in buildings as a
result of misuse of radioactive waste as construction material is one of the
most significant health threats from radioactive waste materials.
Controls of radioactive mining wastes need to take into account site-
specific characteristics. Remote sites with little potential for ground water
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contamination should not be subject to control requirements as stringent as
those sites that are located near population centers and/or potable aquifers.
In some instances, local and State regulations may be sufficient to deal with
some problems, such as use of radioactive mine wastes for building and fill
purposes. Institutional controls such as land use restrictions should also be
evaluated.
Management controls that eliminate transport by various pathways include
capping and other containment techniques. These controls have been successful
in mitigating radon migration, wind dispersal, and infiltration of precipita-
tion. Any monitoring program should be based on site-specific conditions and
management controls used at the site.
Although a large amount of data exists concerning radioactive waste from
mining operations, most of the information concerns uranium tailings piles.
Additional data on the quantities of uranium mine wastes not regulated under
UMTRCA are needed.
The following activities are recommended to support further technical
understanding of the environmental impacts of radioactivity associated with
mining wastes:
Develop a formalized risk assessment methodology
Develop better models to predict radionuclide transport in air, soil,
and water
Integrate existing data for performance of a risk-based evaluation
Collect additional data on the phosphate industry, particularly on the
potential for ground and surface water contamination
Evaluate data on risks associated with radioactive wastes from
nonradioactive mining sectors (e.g., phosphate).
A.3.2.5 Asbestos
There are only three asbestos mines and mills active in the United
States. However, because of the widespread distribution of asbestos minerals,
primarily serpentine, many non-asbestos mine and mill operations present a
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risk of asbestos exposure during processing. The role of asbestos as a
cancer-causing substance through inhalation and ingestion is well-known. The
exact mechanism by which asbestos causes diseasefiber shape, length,
compositionand at what level of exposure, is not well-understood.
Current regulations for asbestos are based on the assumption that the
"long" fibers, greater than 5 microns in length with an aspect ratio greater
than 3:1, present the greatest risk. The optical microscopy analytical
method (NIOSH 7400) on which the regulations are based, cannot detect fibers
smaller than 0.25 microns in diameter. However, thousands of "small" fibers,
detectable only by using transmission electron microscopy techniques, may be
present. This may be particularly true at mill sites where the longer fibers
have been processed, leaving short fibers as waste material. The health
threat posed by small fibers is the subject of ongoing research efforts.
Because conditions vary from site to site, the evaluation of the poten-
tial impacts and selection of management controls must be site specific.
Because the air pathway is the primary concern at many sites, capping or
containment of the waste piles can be an appropriate control. During
operations such as crushing and blasting, wet processing and/or dust control
may be necessary. At all sites with potential human and environmental
effects, air monitoring should be performed to assist in evaluating the
problem and verifying management controls.
Based on a preliminary review of existing information, several activities
are recommended. These include the following:
Determination of the adverse effects of various asbestos minerals and
fiber sizes (especially "small" fibers)
Evaluation of various analytical methods
Collection of data at selected sites using both optical and
transmission electron microscopy techniques
9 Formalization of a risk-based approach to assess potential human
health and environmental effects.
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4.3.2.6 Cyanide
Cyanidation processes are an integral part of the precious metal mining
industry in this country. Cyanide has been used in this manner for nearly a
century. The exact fate and transport of cyanide in the environment is
difficult to predict, but release of cyanide to surface streams has resulted
in fish kills.
The chemistry of cyanide is complex. Cyanide exists as hydrogen cyanide
gas, in solid matrices, or dissolved in aqueous solutions. In aqueous solu-
tions, the cyanide can exist as free cyanide ion, various metal complexes,
molecular hydrogen cyanide, and thiocyanate. Each of these species is subject
to a variety of mechanisms that control its fate and transport in the environ-
ment. The reactions that cyanide may undergo in the environment include
volatilization, photolysis, hydrolysis, adsorption, biodegradation, and
complexation. Because of the variety of pathways and reactions, evaluation
and control measures must be site specific. At many sites, the conditions to
cause potential problems may not exist. For example, in many arid portions of
the western United States, surface water pathways do not exist near the
processing sites.
Because of the complex chemistry of cyanide, analytical procedures to
characterize all species in water and solid matrices have not been standard-
ized or, in some cases, developed. Likewise, the toxicity of each species is
not well documented.
Many of the current management controls emphasize source elimination by
various treatment steps. These techniques can include direct treatment of
leachate to destroy cyanide (e.g., alkaline chlorination) or neutralization of
cyanide in the leached ore heap (e.g., by hypochlorite solutions). Other
management controls include proper siting, design and construction. At all
sites, monitoring of ground water, surface water, and final reclamation are
essential.
Based on preliminary reviews of the available data, limited information
exists concerning the fate and impact of cyanide in the environment. The
following activities are recommended to provide additional information:
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Standardization of analytical techniques to characterize the major
cyanide species in both water and solid matrices
Evaluation of methods to predict leachate quality from the heaps
Evaluation of the toxicity of the various cyanide species
Collection and compilation of analytical results from heap ores and
heap leachates
Evaluation of the fate and transport of cyanide in the environment
Evaluation of the effectiveness of various treatment techniques for
leached ore heaps.
4.3.2.7 Direct Human Contact and Misuse
Some mine waste can pose a health risk when it is ingested or inhaled by
humans. Toxic constituents may be ingested through direct ingestion of
contaminated soil (especially by children) or through ingestion of vegetables
grown in contaminated soil. Direct contact may also occur through handling of
the mining waste materials. Humans may also ingest toxics froiji mining waste
through inhalation of airborne particulates or radioactive gases.
Direct human contact with and misuse of mining waste is likely to occur
when the waste piles are located near a residential area or population center
and access to the waste piles is not strictly controlled.
Dealing with the problem posed by human contact with and misuse of mine
waste requires accurate characterization of the nature and extent of contami-
nation and an assessment of the potential for human contact due to location of
waste piles or accessibility. Management techniques typically involve
reducing or eliminating potential pathways to the receptors. Such techniques
include:
Capping of the waste
Fixation or stabilization of the waste
Control of human access through security systems
Removal and burial of the waste
Institutional control to limit access.
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In all cases, evaluation of the problem and prediction of impacts should
be risk-based and site specific. Flexibility in action level selection should
be incorporated with methodologies that require pathways and receptors to be
demonstrated. Management practices that reduce exposure should be factored
into the methodology.
Consistent and standard analytical techniques for solid samples should be
developed. Techniques should emphasize procedures that yield bio-available
concentrations. In addition, a formal and consistent risk assessment method-
ology needs to be developed for evaluating direct contact with a misuse of
mining waste. The methodology should allow for some flexibility and profes-
sional judgment based on site-specific conditions.
4.3.2.B Catastrophic Slope Failure
Catastrophic slope failure results in an environmental or human health
problem when toxic materials are released from the failure and when the
failure occurs in an area where such a release results in a direct pathway to
receptors.
Slope failure occurs when the geometry of the slope reaches an unstable
configuration, based on the physical (strength) properties of the materials
composing the slope or when the internal mass strength is reduced by seismic
or chemical action. Numerous analytical methods of slope stability assessment
exist, all of which are dependent on accurate evaluation of the physical
properties that contained the strength of the slope mass.
The simplest method for controlling catastrophic failure is to assure
proper initial design, construction and operational and post-closure main-
tenance of the slope. In addition, a monitoring program may be necessary to
verify that the slope remains immobile and that internal conditions do not
change the properties of the materials composing the slope.
A number of methods of monitoring slope movement exist, ranging from
basic surveying through actual slope instrumentation. Those methods are
suitable for post-closure monitoring as well as operational monitoring.
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Additional regulatory support in the evaluation of the actual extent that
slope instability creates an environmental hazard is recommended. A minimum
design standard (checklist) would be a useful tool for future control design
and planning.
4.3.2.9 Common Technical Issues
Each of the previous eight issue areas had specific identified technical
concerns. Examination of these concerns reveals that many of them are common
to the majority of issues. Some of the common technical issues include
development of the following:
Sampling techniques to insure representative samples
Standardized preparation and analytical techniques to insure
consistent and meaningful results
Methodologies to simulate and model fate and transport of the
constituents of concern
Methodologies to address the potential risk, to receptor populations.
The first two common issues focus on the accurate and representative
characterization of the source. The third issue focuses on characterization
and prediction of the transport pathway. The last issue emphasizes evaluation
of the risk to receptors. Therefore, all common technical issues relate to
the definition of the three conditions necessary at a site for evaluation of
risks to human health and the environment. These are:
A potential source of contaminants
A pathway to transport the contaminants
A receptor, resulting in potential exposure.
These conditions further emphasize that the overall regulatory decision
process must be site-specific and risk-based. These common technical issues
are discussed further below.
Techniques for obtaining representative samples will benefit from
additional development and standardization. In particular, the large volumes
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of solid materials existing at mining vaste sites result in unique sampling
problems. The nature of mining waste also results in opportunities to apply
techniques already used in the mining industry. For example, geostatistical
techniques used for defining ore grades can also be used to define the "grade"
or concentration of contaminants in vaste. Even more important, the geo-
statistical tools can also be used to evaluate the level of confidence of the
concentrations at a given location. These methods can then be used to
accurately assess the number of samples necessary to achieve a desired level
of confidence. However, these methods can indicate that extremely large
numbers of samples are necessary to accurately characterize a non-homogeneous
solid waste site.
Besides the evaluations of numbers of samples, further definition is
needed regarding the type of sampling equipment, the size of samples (volumes
to be collected), and sample preservation techniques.
Methods for obtaining accurate and consistent concentrations from the
laboratory analyses (analytical techniques) will also benefit from additional
development and standardization. The methods to digest and analyze solid
samples from mining waste sites should specifically be refined. As discussed
in the previous issue areas, some examples include:
Digestion techniques to represent bio-available constituents
Procedures to accurately predict acid generation potential
Methods to determine cyanide complexes in solid samples
Methods to characterize the complete chemical composition of the
samples
Procedures to accurately simulate the leachability of solid samples in
the environment.
In addition, the necessary types of analyses to be performed on mining
wastes and the media they affect, frequency of sampling, and interpretation of
results for various parameters (based upon temporal changes in the waste pile
and affected media) all deserve further attention, as discussed below.
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Techniques for accurately evaluating and predicting the fate and
transport of chemical constituents in the environment merit additional
development and standardization. In addition to analytical techniques to
simulate leaching (discussed above), procedures to simulate transport in the
environment are needed. These techniques may include batch and/or column
tests. Potential reaction mechanisms and concentration changes can be modeled
using a thermodynamic-based geochemical program. Hydrological modeling can be
used to evaluate and predict water flow and mass transport. These two types
of models are often coupled to accurately predict transport of chemicals in
the environment. Although the need exists to standardize computer models,
professional judgment and site-specific models may often yield useful,
defensible results.
A consistent method to evaluate exposure and risk to receptor populations
would gain from additional refinements. Much progress has been made in the
last few years in developing risk assessment methods. These methods need to
be specifically modified so that they can be used to accurately evaluate
mining waste. The methodology should incorporate the methods, models and
approaches discussed in the previous paragraph to arrive at a consistent
approach that is site-specific. The compilation of Records of Decision (RODs)
for various risk action levels at CERCLA mining waste sites are a good source
of background data.
In addition to the major common technical issues discussed above, some
other less common issues also exist. These include the development of
consistent criteria and screening techniques.
As noted above, these criteria may in many cases result from the risk
evaluation. Screening techniques are necessary in the areas of chemical
analyses and risk evaluation. For example, relatively sensible, cost-
effective "screening" methods would have to be developed to use in Tier 1 and
Tier 2 evaluations under the conceptual program design (Section 4.4).
Once the approach and methods discussed above have been developed,they
must be evaluated using actual case data. That is, the models must work and
be proven to work vith actual site-specific data. This is the ultimate check
of any selected methods.
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4.3.3 Descriptions of Mining Industry Segments
The initial Subtitle D program is anticipated to address wastes from the
extraction and beneficiation of copper, gold, iron, lead, silver, zinc,
antimony, beryllium, mercury, molybdenum, nickel, platinum, rare earth metals,
and vanadium, phosphate rock, uranium overburden and oil shale. Additional
wastes from the processing of aluminum, lead, zinc, and copper may also be
addressed, depending on the regulatory determination which is scheduled for
July 1988 (see Section 2.3 and Table 4-1).
This section provides basic information on the copper, lead, zinc,
uranium, phosphate, asbestos, molybdenum, and aluminum segments of the mining
industry. Other segments may be described in future revisions of this
Management Plan.
4.3.3.1 Copper
The great majority of the copper mined in the U.S. is produced in the
Western States (Arizona alone accounts for over one-half of U.S. production).
Domestic mines produced over 1 million metric tons of copper in 1985.
Extraction and beneficiation of copper ores occurs at large surface mine
operations, which extract sulfide ores for conventional milling and dump leach
operations. Waste rock and ore are extracted from pits and disposed of or
hauled to beneficiation operations, respectively. Where mining activity
occurs below the water table, the mine must be dewatered by pumping. Material
removed from the pit that has recoverable copper but is not suitable for
conventional milling is often processed in a dump leach operation. In these
operations, the ore is piled on a sloping land surface by earth moving
equipment (dozers and graders).. Acid solutions (leach liquors, usually
sulfuric acid) are sprayed on the dump and allowed to infiltrate into the
pile. The acid solution and acid generated by sulfide oxidation dissolve
copper and other metals from the dump material. The solution drains from the
pile at its lowest point on the land surface to a collection pond. Some of
this "pregnant" liquor may percolate into the ground and reach the water table
as a metal-rich acidic solution. Leaching may continue after abandonment of
the dump due to continued acid generation in the dump piles.
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TABLE 4-1. MINING INDUSTRY SEGMENTS TO BE ADDRESSED IN THE
INITIAL SUBTITLE D PROGRAM
Waste Source
Industry Segments
Extraction
Beneficiation
Processing
Metals
mmmmm
illilliillillili:
mmmmm
Aluminum
X
X
X*
Copper
X
X
X*
Gold
X
X
0
Iron
X
X
0
Lead
X
X
X*
Molybdenum
X
X
0
Silver
X
X
0
Zinc
X
X
X*
Other Metals
X
X
0
Nonmetals
mmmmm
mmmmmm
mmmmm
Asbestos
X
X
Oil Shale
X
X
Phosphate
X
X
o
Uranium
X
+
+
Other Nonmetals
0
0
0
Key:
x: To be addressed in the initial Subtitle D program.
*: To be addressed in the second report to Congress and the July 1988
regulatory determination. Wastes not appropriate for Subtitle C
regulation will be addressed in the initial Subtitle D program.
o: Being considered for inclusion in third Report to Congress. Wastes
not appropriate for Subtitle C regulation will be brought under the
Subtitle D program in the future.
+: Excluded from regulation under RCRA due to regulation by Uranium Mill
Tailings Radiation Control Act of 1978 and Atomic Energy Act of 1954.
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High-grade ore is transported for beneficiation to a mill where it is
first crushed in a ball mill or grinding operation, followed by separation of
ore concentrate by froth flotation and related methods. Flotation operations
often require the use of flotation agents such as xanthate solutions with
small amounts of cyanide. Air is bubbled through a flotation cell to create a
floating froth. Because of the affinity of the desired ore minerals for the
flotation agents, these minerals are concentrated in the froth and removed.
The undesired minerals settle to the bottom of the cells and are pumped as a
slurry to the tailings pond where solids settle out in the pond. The con-
centrated froth is transported to a smelting or refining facility.
In 1985, 21 primary copper smelting and refining facilities operated in
the United States. Seven facilities were copper smelters only, two facilities
were refineries only, and four facilities employed both smelting and refining
operations. Four other facilities were closed indefinitely. Nine facilities,
including one smelter/refiner, were electrowinning plants. The total capacity
for refined copper at these plants is 1,453,200 t/yr, of which 1,315,000 t/yr
was from conventional refiners and 138,200 t/yr was from electrowinners.
The three most commonly used processing methods for copper ore and
concentrates are pyrometallurgical processing (smelting), electrolytic
refining, and hydrometallurgical processing (including electrowinning).
Pyrometallurgical processing operations convert copper concentrates to a
moderately purified copper metal called anode copper or fire-refined copper,
depending on the intended use. Most smelters produce copper anodes that are
refined further at electrolytic refineries. The major processes used at
pyrometallurgical smelters include roasting or drying, smelting, converting,
fire refining or anode casting, and sulfur recovery.
During smelting, iron and most other impurities are removed from the
roasted or dried concentrates. The concentrate is separated into a slag and a
copper-iron-sulfide matte in a reverberatory, flash, electric, or Noranda
furnace. The slags usually are hot-dumped or granulated and dumped at onsite
slag dumps. The matte is sent to the next process. In the converting
operations the matte is separated from most of the remaining impurities and is
reduced to crude blister copper. Most smelting facilities operate a sulfur
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recovery plant to clean sulfur-laden gases and to produce sulfuric acid. The
acid-plant blowdown usually is treated at a wastewater treatment facility
prior to disposal of the blowdown solids or sludge.
Important wastestreams generated by copper smelting and refining opera-
tions include slags, collected dusts, wet sludges and slurries, and anode
slimes. Other wastes associated with smelting operations are spent filters
from air pollution control devices and spent furnace brick. Slags are the
most voluminous waste produced and are normally disposed onsite in large waste
piles, or slag dumps. Dusts, collected from virtually all processes, are
recycled back into the process at all facilities. Wet sludges and slurries,
including solids from acid-plant blowdown and other wastewater treatment, are
common wastestreams. Wet sludges are usually disposed or stored in onsite
surface impoundments prior to recycle, whereas wastewaters are treated and
discharged. Anode slimes from electrolysis are recycled, and bleed electro-
lyte may be disposed in an onsite surface impoundment.
4.3.3.2 Lead and Zinc
Lead production from U.S. mines reached 400 thousand tons in 1985, with
Missouri accounting for 90 percent of the total. Approximately 225 thousand
tons of zinc were produced in the same year. Eighty-seven percent of zinc
production originated from mines in Tennessee, New York, and Missouri. Lead
and zinc are produced from underground mines and less waste rock is generated
than by many surface mine operations. Where the workings of underground mines
are developed beneath the water table, the workings must be dewatered by
pumping. Lead and zinc ores are concentrated by conventional beneficiation
methods (see description of copper operations).
Lead is produced by pyrometallurgic smelting and refining processes. The
major process steps are similar at all smelting and refining plants, though in
addition to being smelted and refined, ore concentrates that do not come from
the New Lead Belt in Missouri are additionally treated to recover valuable
metals and remove impurities. A generalized description of lead smelting and
refining follows.
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Smelting is a five-step process by which lead ore concentrate is con-
verted to impure lead bullion that is ready to be refined. The five steps are
sintering, reduction, slag fuming, drossing, and decopperizing. Solid wastes
from lead smelting and refining include air pollution control dust, skims,
slag, spent catalyst, spent furnace brick, used baghouse bags, and vet sludge.
Air pollution control dusts are the combined baghouse dusts and electrostatic
precipitator dusts. All dusts are recycled back into the production process.
Slag includes waste products from reduction, zinc fuming, debismuthizing and
softening. The predominant disposal technologies for slags are onsite waste
piles, and onsite waste piles with secondary recycle. In some instances,
slags are put in a lined surface impoundment and then recycled, or they may be
immediately recycled or put in an unlined onsite landfill. Spent furnace
brick is associated with all processes along the smelting and refining
pathways. The brick is generally sent to a waste pile with a base for a
period of time, after which it is crushed and recycled. Wet sludge is
generated from sintering acid plant processes and wastewater treatment. Wet
sludges are generally sent to an unlined onsite surface impoundment and are
later recycled. A small percentage of sludges are sent to immediate recycle.
The primary zinc processing industry consists of eight operating plants
that produce zinc metal and zinc oxide-. Zinc metal production, carried out at
six plants, can use electrolytic techniques (four plants) or pyrometallurgical
techniques (two plants) to produce slab zinc from unrefined ore.
Production capacity for zinc metal totals 485,000 t/yr, with 310,000 t/yr
available from electrolytic refiners and 175,000 t/yr from pyrometallurgic
refiners. In 1982, the zinc metal industry operated at 61 percent of capac-
ity, producing a total of 295,000 tons of zinc slab. The electrolytic plants
accounted for 214,000 tons of 1982 production, while 81,000 tons were produced
using pyrometallurgical processes. American-process zinc oxide production
capacity totals 95,365 t/yr. In 1982, the zinc oxide industry operated at 61
percent of capacity, producing 58,603 tons.
Solid wastes generated by zinc and zinc oxide processing that may affect
human health and the environment include nonsalable leach residue, wastewater
treatment sludges, furnace residues, and clinker. Wastewater treatment
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sludges are commonly disposed onsite in lined surface impoundments or offsite
in Subtitle C facilities. Nonsalable leach residues are recycled approxi-
mately 50 percent of the time, with about 10 percent of the residues disposed
of in lined surface impoundments, and 37 percent of these wastes disposed of
in unlined impoundments. Clinker and furnace residues are disposed of in
onsite waste piles.
A.3.3.3 Gold and Silver
Domestic mines produced 2.40 million troy ounces of gold and 43.0 million
troy ounces of silver in 1985. Many mines are operated as gold mines that
produce silver as a valuable byproduct. Gold and silver are recovered from
ore by two processes: cyanidation in vats, tanks, or closed containers; and
heap leaching. Conventional cyanidation recovers up to 90 percent of precious
metals from ore, compared to 50 to 85 percent recovery for heap leach opera-
tions. Because of the lover capital and operating costs, heap leach recovery
may be profitable for recovery of gold from low-grade ore (as lov as 0.03
ounces/ton). In 19B4, 1.14 million troy ounces of gold were recovered from 12
million tons of ore by conventional processes, while heap leaching recovered
0.52 million troy ounces of gold from almost 20 million tons of ore.
Conventional recovery operations are concentrated in Nevada, California,
and Idaho. Of approximately 80 currently active heap leach operations, 60 are
located in Nevada, with the majority of the remainder located in other western
states.
Gold and silver are mined at surface and underground mines. Only higher-
grade ores are mined underground, while both high- and low-grade ores are
recovered at surface mines. High grade ores (>0.09 oz/ton) are beneficiated
at cyanidation plants. The ore is mechanically crushed and introduced into
vat or tank cyanidation processes. The precious metals are extracted by
complexation with the cyanides. The tailings are pumped as a slurry to a
tailings pond to settle.
Low-grade ore is subject to heap leaching to recover the precious metals.
Ores suitable for heap leach recovery contain disseminated submicron-sized
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particles of precious metals in the ore. If the ore contains fine-grained
clayey material that reduces the interaction of leach solutions with precious
metals, the ore may be subject to agglomeration. The ore is crushed to a
uniform size, 5 to 10 pounds of portland cement per ton of ore is added along
with water or cyanide solution and the mixture is tumbled and cured.
Agglomeration causes finer particles to adhere to larger pieces of ore. This
prevents migration of finer particles during leaching that would obstruct void
spaces in the heap and retard leaching. The prepared ore is stacked on the
leach pad. The leach pad is an impermeable surface that prevents loss of the
pregnant leachate through seepage into the ground. The pad is sloped so that
leachate draining from the heap collects in a lined solution pond. The pad is
constructed on compacted native soil and pad designs range from single layer
compacted clay to multiple synthetic liners with leachate detection systems.
Because of the high value of the pregnant solution, sophisticated systems may
be employed to ensure collection of leachate from the heap. Pads range in
size from less than 1 acre to 50 acres. Ore is moved onto the heap and graded
by earth moving equipment. After completion of a leaching cycle, fresh ore
may be added to the heap for the next leaching run or the spent ore may be
removed before ore is stacked on the pad for the next cycle.
Leaching occurs when "barren" solution (1 lb NaCN/ton-, buffered to pH
10.3) is sprayed on the heap. The solution removes gold and silver from the
ore, percolates downward to the pad, and collects in the solution pond. If
the pH of the solution decreases in the heap, free cyanide may be generated,
leading to volatilization from the solution pond. Solution ponds often are
constructed of single layer synthetic liners over compacted soil. The
solution pond must have a holding capacity sufficient to contain leachate from
the heap and additional flow due to storm events. An emergency overflow basin
often is located downgradient from the solution pond to intercept any
accidental overtopping.
"Pregnant solution" is pumped to a metal recovery process, where the gold
and silver are removed and barren solution is returned to the heap leach
operation. Barren solution is stored in the barren solution pond (similar to
the solution pond in construction). Barren solution is treated to achieve the
desired composition before application to the heap for continued leaching.
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Cyanide can be removed from spent heaps by a variety of processes. After
completion of the leach cycles, the heap may be leached with water to recover
remaining cyanide, or an oxidant, such as hypochlorite, may be added to the
heap to react with the cyanide. Any remaining cyanide may be subject to
volatilization, biodegradation, or adsorption to soil minerals and organic
matter.
4.3.3.4 Uranium
Uranium is produced by underground and surface mines and by in situ
leaching operations. Beneficiation and processing wastes are excluded from
RCRA due to the statutory provisions of Uranium Mill Tailings Radiation
Control Act of 1978 and the Atomic Energy Act of 1954, and will not be
considered in the regulatory development process. Colorado had 35 mining
sites, the largest number of uranium mining sites in the U.S., followed by New
Mexico, which had 11 sites. Uranium mining activity in 1984 also occurred in
Wyoming, Utah, Texas, and Washington. Seventy-three million tons of waste
rock were generated by uranium mines in 1982.
In conventional uranium mining, ore is transported from the surface or
underground mine to a mill and stored in a pile to await processing. Waste
rock is hauled out of the mine and dumped on a waste pile.
If a mine must be dewatered, Ra226 rich wastewaters can be generated.
Treatment of mine waters with barium chloride reduces the activity of radium,
but elevated barium levels often are found in waters treated by this process.
Also, these waters may still retain high radioactivity levels due to Ra226,
U2 3 5 , U2 3 8 , and Th232 These mine waters are usually pumped to holdings
ponds, where volume reduction occurs due to evaporation and seepage into the
ground.
In situ leaching is a method used to recover uranium without extracting
the ore from its subsurface setting. Explosive charges are placed into
drilled holes at the surface and are detonated to fracture the ore body. The
fracturing pattern is designed to generate sufficient permeability into the
ore body so that leaching fluids can be injected into the ore and withdrawn
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through pumping wells. Oxygen-rich water from the surface is injected into
the ore body. Reduced uranium in the ore minerals is oxidized by the injected
water and dissolves into the water. This uranium-rich water is extracted
through withdrawal wells and is chemically treated to recover the uranium.
Processed water may be returned to injection wells or otherwise used or
disposed at the surface. Because the uranium ore often occurs in sandstones
with a pre-existing ground-water flow regime, not all of the uranium mobilized
by the in situ leaching process may be recovered by the withdrawal wells.
4.3.3.5 Phosphate
In 1985, 51 million tons of marketable phosphate were produced from
approximately 174 million tons of domestically mixed phosphate ore. Approxi-
mately 435 million tons of waste rock were generated by this mining activity.
Florida and North Carolina accounted for 86 percent of production, with the
remainder produced in Idaho, Tennessee, Utah, and Montana. Phosphate rock is
produced by extraction of ore from surface mines and beneficiation at nearby
mills. Waste rock is disposed in piles, spread over adjacent land or back-
filled in abandoned areas of the surface mine. Radiation exposure from waste
rock and tailings may occur from airborne particulates or from Radon222
generated by radioactive decay. Radioactive elements also may be leached from
waste piles and tailings by precipitation and transported to ground and
surface waters.
Elemental phosphorus is obtained from phosphate rock by electric furnace
production. Coke and silica fluxes are added to phosphate rock to make up the
furnace charges. Calcium silicate slags produced by furnace operations may
contain enough radioactive uranium to impact human health and the environment.
Particulates collected from the off-gas scrubber are probably fines of coke,
phosphate rock, and silica that may be recycled. Phosphorus condenser water
may contain fluorides and other soluble contaminants.
Phosphoric acid is produced by reacting phosphate rock with a strong
acid, usually sulfuric acid. .This process, known as acidulation, produces
fluosilicic acid and gypsum. The fluosilicic acid is volatile and is removed
by off-gas scrubbers. This material is corrosive and contains high levels of
fluorides. Some processors sell fluosilicic acid as a fluoridation agent.
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4.3.3.6 Asbestos
Three mines (2 in California and 1 in Vermont) produced 61,000 metric
tons of asbestos in 1985. Approximately 7 million tons of waste are generated
each year by the asbestos mining industry. Asbestos fibers in tailings and
overburden may become airborne and present a risk of inhalation exposure for
nearby populations. Asbestos minerals also may be present in waste rock and
tailing produced by other industry segments. Asbestos is easily eroded and
may be removed from disposal and mine sites along with other suspended solids
in runoff.
4.3.3.7 Molybdenum
Molybdenum production totaled 107 million pounds in 1985. Molybdenum
mines wete operated in Colorado, New Mexico, California, and Idaho.
Molybdenum also was recovered as a byproduct of copper mining in Arizona,
California, New Mexico, and Utah. Molybdenum is produced from ores containing
sulfide minerals. Many of the environmental concerns due to the conventional
mining and beneficiation of copper ores apply to molybdenum. Specifically,
the potential for generation of acid and toxic metal-bearing waters that may
contaminate ground and surface waters may affect the environment in a similar
manner to those discussed for copper mining.
Molybdenum ore concentrates are used directly in lubricant production or
processed into molybdic oxide for use in chemical and ferroalloy industries.
Molybdic oxide is processed by molybdenite roasting, which produces sulfur
dioxide and particulates.
4.3.3.8 Aluminum
In 1985, surface mines in Alabama and Arkansas produced 565,000 tons of
bauxite. Approximately 80 percent of domestic and imported bauxite was
converted into alumina for consumption at aluminum smelters.
Because bauxite occurs in essentially homogeneous deposits, the ore is
not subjected to conventional milling after extraction. Extraction occurs in
large, open pit mines where overburden and ore are removed by draglines and
other earth moving equipment. Fugitive dust emissions and suspended solids in
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surface waters may result from mining. However, bauxite and associated
materials often have very lov trace metal contents and little or no acid
generating potential.
Bauxite refining is achieved through the Bayer process. Raw bauxite is
processed into calcined alumina for use in primary aluminum reduction. The
bauxite is crushed and screened to remove clay, silica, and other impurities.
The ground bauxite is digested in a NaOH solution and settled solids (known as
"sand") are removed and disposed. The sodium aluminate solution is treated to
remove iron oxide and silica. Other undigested materials are separated as
"red mud." This material is disposed in an impoundment with liquids charac-
terized by high pH, dissolved metals (iron and other metals), and phenolic
compounds. Aluminum hydroxide then is precipitated from the sodium aluminate
solution and is calcined into anhydrous alumina.
Primary aluminum is produced from alumina by electrolytic reduction.
This process produces aluminum metal by electrolyte cells containing cryolite.
This electrolyte is a fluoride salt of calcium and aluminum. The electrolysis
is conducted in carbon-lined cells or "pots" that act as the cathode of the
cell. The anode is made from a paste of coal tar pitch and coke.
Wastes produced by the electrolytic reduction of aluminum that may affect
the environment include spent potliners, shot blast dust, pot skims, and vet
sludges. These wastes contain elevated levels of fluoride, cadmium, and
cyanide that may be mobilized into the environment. Spent potliners and shot
blast dusts may be stored for recycling or disposed in landfills. Pot skims
are disposed in lined or unlined landfills. Uet sludges are placed in lined
or unlined impoundments.
4.4 CONCEPTUAL PROGRAM DESIGN
Technical evaluations, prepared from data in studies of the mining
industry and summarized in Section 4.3.2 and Appendices A through I, have led
to the development of a preliminary conceptual program design for the regula-
tion of mining wastes under Subtitle D of RCRA. This design illustrates one
potential approach to identifying mining operations and wastes that pose the
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highest risks to human health and the environment. It also outlines methods
for identifying the types of site-specific regulatory controls and permitting
procedures that may be needed at various types of mining operations. However,
this program design must undergo a series of technical, legal, and policy
analyses before it could be adopted by the Agency (see Section 4.5.1).
Therefore, the Agency is presenting this preliminary conceptual design to
elicit comments from potentially interested parties. It should be emphasized
that the general and specific conceptual designs described below are pre-
liminary in nature and are presented to generate discussion. They do not
represent Agency positions and should not be construed as committing the
program to a tiered approach. Comments should assist in the assessment of the
strengths and weaknesses of this design and could be valuable in recommending
other approaches that may be more relevant for regulating mining wastes.
A diagram of the preliminary conceptual program design for regulating
mining wastes is presented in Figure 4-2. It reflects a simple format for a
three-tiered regulatory program. It is structured to show all mining opera-
tions (box MO) in the lower left-hand corner of the diagram. The decision-
making process is three-tiered, with risk-based regulatory decisions made in
each tier and regulatory requirements progressively more stringent for higher
tiers. Using screening and evaluation methodologies, each mining operation
would be classified as having a low, medium, or high risk potential for
regulatory categorization purposes. Each tier would represent an increasing
level of regulatory scrutiny. The higher tiers would focus on the analysis
and control of an issue such as acid generation. The various environmental
and public health risks levels (i.e., tiers) might be explained as follows:
Tier 1 - Low Risk
Sites in Tier 1 present relatively low risks from environmental and
public health perspectives, and all mining operations would initially
be included in such a regulatory tier. All sites would be subject to
routine notification and reporting requirements regarding their mining
activities, waste generated, management practices, and related site
characteristics.
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DEM
IMPLEM T2
MGMT PRAC
IMPLEM T1
MQMT PRAC
KEY
MO ¦ Mining Operation
T1 - Regulatory Tier
DEM - Detailed Evaluation
Methodology
? - Decision Block-
Risk Score
SSM - Site Screening Methodology
FIGURE 4-2. CONCEPTUAL PROGRAM DESIGN: TIERED APPROACH
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Tier 2 - Medium Risk
Regulatory requirements for Tier 2 sites would include all those
required for Tier 1 in addition to more stringent requirements, which
could include: (1) permit application, site-specific evaluations and
approval; (2) monitoring, reporting, and verification; (3) implementa-
tion of management practices adequate to resolve identified problems;
and (4) permit renewal every five years.
Tier 3 - High Risk
Sites in Tier 3 would include all Tier 1 and Tier 2 requirements in
addition to: (1) more stringent permit application and approval
processes; (2) more stringent monitoring, reporting, and verification
requirements than Tier 2; (3) implementation of management practices
necessary to control mining waste sufficient to remain within the
upper regulatory bounds of the program; and (4) longer term closure
requirements.
It is envisioned that the Subtitle D program will address facility
development, operation, closure, and postclosure maintenance regardless of the
approach adopted. In this conceptual design, the various tiers would address
the issues in different levels of detail, but all tiers would involve problem
identification, problem solution on a site-specific basis, and verification of
the solution over time.
The means by which a mining operation would be regulated in one of the
three tiers are described below.
1. All mining operations initially would be categorized in Tier 1
(notification and reporting), at the lower left-hand side of the
diagram (box MO on Figure 4-2).
2. Following placement in the low-risk regulatory Tier 1, all sites
would undergo initial screening using the site screening methodology
(box SSM), moving vertically up the left-hand side of the diagram.
This screening methodology would be based on waste characteristics
and site specific factors and would include several types of deci-
sions regarding key technical issues that affect environmental and
public health risks. This screening analysis would have limited
resolution (i.e., it would not be a detailed methodology).
3. All sites with mining waste management conditions that suggest
further regulatory control (by affirmative answers to risk-related
decisions represented by diamond blocks) would move into the Tier 2
regulatory level. If negative answers were generated for all of the
risk decisions, the mining operation would be categorized as Tier 1
and be subject to specific Tier 1 requirements.
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4. After a site was determined to reside in Tier 2, it would undergo
further screening, using a detailed evaluation methodology (box DEM)
to determine if it should be categorized as Tier 3. This would
involve a more detailed and extensive screening methodology, con-
sidering various factors known to cause such a site to move from
medium environmental and human health risks to high risks.
Affirmative answers to risk parameters (diamond blocks) would place a
site in Tier 3, while negative answers would categorize the site in
Tier 2.
5. Once in the high-risk Tier 3 regulatory situation, a site would have
to identify the critical pathways and control those to protect human
health and the environment. Verification and corrective action would
be required if initial controls were not adequate.
Figure 4-3 is a preliminary conceptual design of a potential assessment
methodology for a specific technical issue. This example shows the means by
which a site could be placed in Tier 1, 2, or 3 based on acid generation
potential.
In order to develop the regulatory program details, various options for
obtaining acceptable risk levels at mining sites must be considered. The
following is a partial list of options for consideration.
Containment
Controlled release
Pathway interruption
Mitigation - treatment
Receptor Controls - land use controls, fencing for wildlife
The technical issue papers, summarized in Sectino 4.3.2 and contained in
Appendices A through I, describe several identified technical issues of
concern regarding mining wastes. These will serve as the basis from which to
develop more detailed and substantiated methodologies.
4.5 REGULATORY DEVELOPMENT ISSUES
The regulatory development process will produce a proposed rule, sched-
uled for Federal Register publication in April 1989. The development of the
proposed rule will be preceded by several Workgroup meetings to develop
regulatory issues and options; by reviews of issues and options by senior
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Detailed Site
Characterization
Detailed Leachate
Characterization
Detailed
Modeling
Rerr.cin in
'Tier 3
rO
C£.
Hydrologic
investi-
gation
Column
Testa
Risk
Assess, k.
Transport
Model
Oetailed Management
Plan Including Monitoring
and Permitting
CM
&
Limited Leachate
Characterization
Limited Risk Screening
it Modeling (includes
Limited Site Characterization
a:
u
1=
8atch or
Column
Tests
Risk
Screen
Modeling
c
w
3
cc
o
a.
zi
rn
3
Infiltration
Management
and
Monitoring
C£
UJ
P
Limited Waste
Characterization
No
Lim
ted
Reporting
Limited Site
Charccterization
Yes
Simple
Acid/
Base
Account
=1
m
FIGURE 4-3. EXAMPLE OF POTENTIAL ASSESSMENT METHODOLOGY: ACID GENERATION
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management as appropriate; by at least one regulatory options selection
meeting; and by a "straw man" draft of the proposed rule (see Section 2.2).
This section presents major regulatory issues that are preliminary candidates
for early review by the Workgroup and by senior management. These issues
address the
Overall regulatory approach to the rulemaking
Relationship between the Subtitle D program and existing regulatory
structures
Potential scope of the Subtitle D program
New technical methodologies and standards that may be needed to
support the rulemaking.
The discussions of these issues presented below include descriptions of
each issue and major subissues, references to the data collection efforts
outlined in Chapter 2 that are being conducted to resolve the issues, and
possible' needs for future data collection activities.
The issues presented in this section are preliminary and subject to
change, and additional issues may be identified. For this reason, this
section of the Management Plan may be revised periodically as regulatory
development proceeds.
4.5.1 Issue 1: Overall Approach to the Rulemaking
This section discusses two main subissues that must be addressed to
determine how the new rules for mining wastes will be structured and applied
to the regulated community. These subissues are:
Regulatory Approach
Enforcement Authorities
These issues are discussed separately below.
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4.5.1.1 Issue 1A: What Should be the Regulatory Approach?
A preliminary conceptual design for the regulatory program was presented
in Section 4.4 of this Management Plan. However, this design has not been
subject to the detailed technical, policy, and legal analyses that must be
applied prior to final selection of a regulatory approach by the Agency. The
Agency may develop a number of alternative regulatory approaches and assess
the relative strengths and weaknesses of each in terms of a number of factors,
including their abilities to:
Protect human health and the environment;
Address the technical feasibility, environmental necessity, and
economic practicality of mining waste controls;
Serve as a tailored risk-based approach that addresses the diversity
and unique characteristics of mining waste problems;
Consider existing Federal and State mining waste programs, with a view
toward avoiding duplication of effort.
The goal for development of alternatives is to match or exceed the degree
of environmental protection, flexibility, and risk tailoring in the tiered
approach outlined in Section 4.4, while emphasizing the ease of implementing
the rule. The development of alternatives began only recently, so these
alternatives are presented as basic regulatory concepts that were considered
in previous regulatory development efforts (for wastes other than mining
wastes) under RCRA. These concepts include:
Minimum uniform standards for all sites, with guidelines for the
application of more stringent requirements by the States.
Comprehensive uniform standards for all sites, with guidelines for
application of less stringent requirements by the States.
A categorical approach, whereby sites are matched with specific
standards depending on a number of general risk-related criteria.
A risk-modeling approach, whereby numerous data on waste constituents,
concentrations, management methods, release pathways, migration
parameters, etc. are processed in computerized models to isolate those
¦factors that are the best predictors of the risks posed by mining
operations in a variety of environmental settings. Site-specific
regulations are developed by collecting data from each site and using
them in the model which determines the controls needed to reduce the
site-specific risks.
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A tiered approach (as described in Section 4.4).
Combinations of the above.
Minimum uniform standards are appropriate when environmental data show
that a large proportion of the regulated community presents common types of
low level risks and when few, if any, sites present high levels of risks. A
rule resulting from such an approach would protect human health and the
environment, be relatively easy to implement because of uniform standards, and
address the few high-risk sites with additional standards. In addition, the
majority of the regulated community would not be burdened by unnecessarily
stringent requirements.
Comprehensive uniform standards are appropriate when a large proportion
of the regulated community presents common types of high level risks, and when
few, if any, sites present low levels of risk. The resulting rule would be
protective, relatively easy to implement, and could address the few low-risk
sites by allowing site-specific reductions in requirements.
A categorical approach, although harder to develop and implement than
other approaches, is appropriate when the regulated community includes many
sites in a wide variety of risk categories. A rule resulting from this
approach would describe a number of risk criteria (based on site location,
waste types, management practices, or other factors) that would be used to
determine which set of predetermined standards to apply to a particular site.
A risk modeling approach is appropriate when sufficient data are avail-
able to develop and validate a model using a minimum of assumptions. Such a
model must demonstrate a low potential for under- or overestimating risks, and
a method for determining when such inaccurate results are most likely to
occur must be developed for this type of approach.
Combinations of the foregoing approaches are appropriate when the
regulated community exhibits more than one of the characteristics described
for the other regulatory concepts.
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The basic difference between the approaches described above and the
tiered concept described in Section 4.4 is the amount of site-specific data
used to apply regulatory controls to a particular site. Both the minimum
uniform and comprehensive uniform approaches require a minimum of site-
specific information, but have the greatest potential to overregulate or
underregulate specific sites. Categorical and risk modeling approaches are
more similar to the tiered concept; however, the latter are implemented with a
minimum of site-specific data, thus reducing the time needed to determine
basic standards at each site. The categorical and risk-modeling concepts allow
the use of site-specific data to refine the basic requirements within each
category, depending on specific risk factors not considered when setting the
basic standards.
Data Collection Activities/Needs for Issue 1A
Chapter 2 of this Management Plan presented all of the data collection
activities that have been initiated to support the rulemaking. The most
important data needed for resolution of Issue 1A are those related to descrip-
tions of the regulated community. These descriptive data are being addressed
by compiling and analyzing existing information (Section 2.2.1.1) and CERCLA
site information (Section 2.2.1.2); by developing technical issues papers
(Section 2.2.1.3 and Appendices A through I), by conducting site visits
(Section 2.2.1.4); completing risk screening (2.2.1.7); and by reviewing State
and Federal programs (Section 2.2.1.5). Preliminary results of these
activities will be included in the draft regulatory support document scheduled
for October 1987. These results are expected to be adequate for resolving
Issue 1A and for determining future data collection efforts that may be needed
to refine the selected regulatory approach.
4.5.1.2 Issue IB: How Should the Present Administrative and Enforcement
Authorities Under Subtitle D be Revised for Mining Wastes?
The RCRA Subtitle D program is administered and enforced by the States
and does not provide for Federal oversight and enforcement except for
facilities that may receive hazardous household wastes (HHW) or small quantity
generator (SQG) wastes. Since mining sites are unlikely to receive HHW or SQG
wastes, EPA currently does not have the legal authority to require States to
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adopt any new Federal Subtitle D program for mining wastes, nor does EPA have
the authority to enforce a program in States that do not have adequate
programs. EPA stated (51 FR 24496, July 1986) that it would work with
Congress to develop expanded Federal authority, and that preliminary contacts
had been made.
Data Collection Activities/Needs for Issue IB
The key activity being conducted to resolve Issue IB is discussed in
Section 3.3. This involves discussions with congressional personnel through
the Agency's Office of Congressional Liaison. These discussions are expected
to result in revisions to RCRA Subtitle D that allow increased Federal
authorities, State responsibilities, and possibly funding to the States to
implement and enforce the new mining waste regulations. The Agency must
interpret the RCRA revisions and prepare alternatives for determining how the
new rule will be applied. These alternatives will be developed for review by
senior EPA officials as the Agency determines the types of RCRA revisions that
must be made by Congress. The resolution of Issue IB is critical because it
will significantly influence the resolution of Issues 1A and 2. Therefore,
the Agency will attempt to expedite its meetings with congressional staff
members to determine what additional authorities are necessary and possible
under Subtitle D of RCRA.
4.5.2 Issue 2: What Should be the Relationship Between the Subtitle D
Program and Existing Regulatory Structures?
Mining industry operations to be addressed in this rulemaking are
currently regulated by the Bureau of Land Management, the Forest Service, and
other Federal and State agencies (Section 4.2). This rulemaking will add
another Federal agency (the EPA) to the list of mining regulators. The
resolution of Issue 2 will determine how all these regulatory authorities will
interact to avoid duplicative or conflicting requirements, minimize the
reporting requirements of the regulated community, and establish clear lines
of communications among the various authorities. The relationship could take
several forms, ranging from the current Subtitle D (where EPA prescribes
general criteria for State guidance, but where EPA has no oversight or
enforcement authority) to the current Subtitle C (where States that adopt
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requirements with programs no less stringent than EPA requirements may receive
primacy) to the Underground Injection Control program (in vhich EPA prescribes
programs specific to individual states in States without primacy).
Data Collection Activities/Needs for Issue 2
The review of State and Federal programs (Section 2.2.1.5) is now being
conducted to support this issue. It is a significant activity and is expected
to provide sufficient preliminary information for resolving part of Issue 2
early in the regulatory development process. As data is collected and
analyzed against conceptual designs, Issue 2 can be developed fully, then
reviewed by senior EPA officials and resolved.
4.5.3 Issue 3: Potential Scope of the Subtitle D Program
The resolution of this issue will determine which types of facilities
will be regulated within the mining industry segments that are addressed under
the current rulemaking. It contains a number of subissues including:
Applicability to active, inactive, abandoned, new, and existing
facilities and sites
Applicability of RCRA versus CERCLA
Boundaries of the Bevill exclusion
Distinctions between process materials and wastes
Waste management controls at combined extraction, beneficiation, and
processing sites
Mining segments to be considered in future Subtitle D rulemaking
efforts.
4.5.3.1 Issue 3A: How Should the Regulations Apply to Abandoned, Inactive,
New, and Existing Facilities and Sites?
This issue is described below as a series of subissues, each addressing a
different type of mining site. Specifically:
Should the regulations apply to closed or inactive portions of
existing facilities or sites?
There are a large number of closed and inactive mining facilities
across the country. Some of these are on the same sites as currently
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active mines. Between 1982 and 1984, approximately 200 extraction and
beneficiation operations were closed within the segments to be
addressed in the initial regulatory program. Many of these sites may
pose threats to human health and the environment; however, it may be
extremely expensive for States and mining companies to assess the need
for remediation of these sites. Therefore, further data collection
and analysis will be required to determine whether to address any or
all of these sites under the current rulemaking. One alternative may
be to provide States and relevant Federal agencies with guidance
and/or funds for addressing these sites.
Should the regulations make distinctions between active existing and
new facilities or sites?
The Subtitle D program may require additional standards for designing
and operating waste management units. It is possible that these new
requirements could pose severe financial hardship or could increase
risks to human health and the environment if they were required at
existing waste management units. For example, retrofitting a liner at
a tailings impoundment would be extremely costly for almost all mining
operations. Therefore, it may be necessary to phase in or develop
alternative requirements for existing mine sites.
Should there be special requirements for closed, inactive, or aban-
doned facilities or sites that are reactivated after the regulatory
program is in place (e.g., should they be regulated as new or as
existing sites, or should other rules apply)?
Mining companies often close or deactivate facilities during periods
of low demand for the commodity. When economic conditions become more
favorable, companies may reactivate these facilities. One operator
may also commence operations on a site abandoned by another operator.
If the requirements developed under the present rulemaking treat these
reactivated mines the same as new mines, there would be no incentive
to reactivate old mines and possibly mitigate past environmental
damages. This issue will examine whether there should be means to
maximize incentive to reopen (and improve) old sites without resulting
in inconsistent requirements.
Data Collection Activities/Needs for Issue 3A
The Agency is collecting data on the numbers of and environmental
conditions at closed, inactive, abandoned, new, and existing facilities as
part of the review of existing data (Section 2.2.1.1) and CERCLA site data
(Section 2.2.1.2); through development of technical issues papers (Section
2.2.1.3); through site visits (Section 2.2.1.4), and through the Second Report
to Congress (Section 2.3). These data will be developed in time to provide
adequate support for recommending basic options for Issue 3A. It is antici-
pated that these data may indicate a need to collect additional data on
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closed, inactive, and abandoned sites. However, it is premature to begin
additional data collection efforts until the existing data are analyzed.
4.5.3.2 Issue 3B: What is the Relationship Between RCRA and CERCLA Standards
and Mining Sites?
The Comprehensive Environmental Response, Compensation, and Liability Act
of 1980 (CERCLA) established the Superfund program to deal with releases and
potential releases of hazardous substances, including hazardous wastes. The
Superfund program ranks sites where releases have occurred, or where there is
a substantial threat of a release, using a Hazard Ranking System (HRS). Sites
scoring above a certain score using the HRS (i.e., those that pose the most
significant risks) are then included on the National Priorities List (NPL).
The Superfund Amendments and Reauthorization Act of 1986 (SARA) added
Subsection 105(g) to CERCLA. This subsection provides that, pending a
required revision of the HRS, EPA must consider certain factors before adding
"special study waste" sites (which include mining waste sites) to the NPL.
Factors that must be considered include (1) the extent to which the HRS score
is affected by special study wastes, and (2) available information on the
quantity, toxicity, and concentration of hazardous substances that are
constituents of the waste, potential for release, potential exposure from
release, and the degree of hazard posed by release. In general, the Superfund
program is intended to be a remedial, or reactive, program rather than a
preventive program. Until a program for mining waste under Subtitle D is
developed to address such hazards, EPA has stated its intention (51 FR 24496,
July 3, 1986) to use its authority under CERCLA to protect against substantial
threats and imminent hazards from mining wastes.
This issue will address the consistency between the consideration of
environmental factors used in the HRS under CERCLA and the new Subtitle D
standards that are now under development. This issue will also address the
transition from the use of CERCLA authority to the use of Subtitle D standards
to protect against threats and imminent hazards at existing mine sites, thus
reducing the need for CERCLA involvement at many mining sites. In addition,
CERCLA programs will be analyzed to determine the effects of using alternative
Subtitle D standards in developing the appropriate levels of cleanup at CERCLA
sites. The new RCRA standards under this rulemaking are expected to become
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the applicable or relevant and appropriate requirements (ARARs), which must be
considered during CERCLA cleanup actions.
Data Collection Activities/Needs for Issue 3B
Data on current CERCLA mining sites are nov being compiled (Section
2.2.1.2) to assist in the understanding of the types and levels of remedial
actions nov being conducted at these sites, and any changes that were
initiated due to the 1986 amendments. Efforts are now underway to develop
close working relationships with Agency staff who are responsible for revising
the HRS and developing the new cleanup standards required under SARA. These
data collection activities will be sufficient to further refine Issue 3B for
review by senior management and to refine this issue for further discussions
and decisions that will be required in developing and adopting a complete
conceptual design.
4.5.3.3 Issue 3C: What are the Boundaries of the Bevill Exclusion at
Processing Facilities
OSV is committed under this rulemaking to conducting a study under RCRA
Section 8002 and preparing a report to Congress on selected ore and mineral
processing wastes that are conditionally excluded under the Bevill Amendment
from regulation as Subtitle C wastes. However, there is uncertainty within
the Agency and the regulated community as to which wastes are covered by the
Bevill exclusions. This issue must be resolved to ensure that appropriate
wastes are studied. Specifically, the following questions must be answered:
Should excluded wastes be limited to wastes from only those operations
that directly process ores and minerals, or should processing wastes
also be from auxiliary operations excluded from regulation under
Subtitle C?
What wastes are uniquely associated with the extraction, beneficia-
tion, and processing of ores and minerals?
At what point does further processing of a mineral product remove the
resulting wastes from the mining waste exemption?
Are residuals of Bevill waste processing likewise Bevill wastes?
What is the status of wastes derived from processes utilizing both
primary and secondary feed stocks?
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What effect does the use of hazardous waste as a fuel have on the
Bevill status of process residues?
Are wastes produced by alloying, fabrication, or other manufacturing
operations excluded by the Bevill Amendment?
Are wastes derived from the operation of pollution control equipment
excluded from regulation under Subtitle C?
Does a waste which would normally be excluded lose that exclusion if
it derives from a process off-site from the principal processing
operation? And secondly, do otherwise excluded wastes derived from
the refining of intermediate products lose their status if those
intermediate products have been sold to another party for refining?
In addition to resolving the Bevill boundary issue for the processing
wastes that may initially be covered in the Subtitle D program, the Agency
must resolve this issue for other mining industry segments (e.g., those that
will be addressed in the third Report to Congress).
Data Collection Activities/Needs for Issue 3C
Activities undertaken for the second report to Congress (Section 2.3)
have yielded significant information for resolving Issue 3C for wastes
produced by four mining industry segments. This issue is being discussed and
resolved concurrently with the development of the second report to Congress
and will be included as a chapter within this report (Section 2.3.1). The
Agency also is collecting data on the segments being considered for the third
report to Congress (Section 2.4) to ensure that the resolution of Issue 3C
will provide a consistent approach for determining the Bevill boundaries for
these other mining segments. No further data collection activities for
resolution of Issue 3C are anticipated.
4.5.3.4 Issue 3D: What are the Regulatory Distinctions Between Process
Materials and Wastes?
Wastes from dump/heap leaching operations (i.e., operations where water,
acid, or cyanide-bearing solutions are percolated through piles of mine waste,
tailings, or other materials and then collected to recover valuable metals)
can be discharged directly into the environment. Under RCRA, neither the
pile, the liquid, nor the collected liquor are considered to be wastes (while
leaching operations are continuing). However, any liquor that escapes through
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the bottom of the pile, and the pile itself, upon abandonment, are wastes.
Because RCRA currently does not address production processes, differently
structured requirements may be needed to modify the design or operation of
heap and dump leaching processes.
Data Collection Activities/Needs for Issue 3D
Information on dump and heap leaching operations are being collected and
analyzed from existing data (Section 2.2.1.1), CERCLA site data (Section
2.2.1.2), through development of technical issues papers (Section 2.2.1.3),
through site visits (Section 2.2.1.4), through risk screening (Section
2.2.1.7) and through specific studies and modeling efforts (Section 2.2.1.8).
These activities will produce a large body of information to support the
development of alternatives for determining where and how to regulate heap and
dump leaching operations. Information from site visits and from specific
studies and modeling efforts will become available in later stages of the
regulatory development process (in late 1987 and in 1988). Initially, basic
questions concerning Issue 3D may focus on regulatory alternatives that are
now available for controlling heap/dump leaching operations and on studies
that may be needed to develop additional alternatives.
4.5.3.5 Issue 3E: How Should Waste Management Controls be Applied to
Combined Extraction, Beneficiation, and Processing Sites?
A number of mining sites have co-located beneficiation and/or processing
operations. These co-located operations may result in different methods by
which wastes are managed than at sites where only one operation occurs. For
example, some wastes may be mixed with others prior to disposal in a tailings
pond, thus increasing (or reducing) the environmental risks posed by the pond.
The Agency plans to investigate the effect of co-located mining operations on
waste management practices in order to determine whether increased or
decreased regulations may be appropriate at these sites. The Agency is
particularly interested in identifying co-located operations where the
resulting waste management practices may eliminate or reduce some risks and
thus require reduced levels of regulatory control. The Agency is also
interested in determining whether some of these waste management practices may
result in greater mobilization of some wastes into the environment, thus
requiring increased control or prohibitions.
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Data Collection Activities/Needs for Issue 3E
The main data collection activities being pursued to support Issue 3E are
the site visits (Section 2.2.1.4) and the Section 3007 surveys (Section
2.2.1.6). Visits to collect data at sites with co-located beneficiation and
processing operations may be conducted in August 1987. In addition, the
Agency expects to receive information in August from the mining industry and
the Bureau of Mines regarding these sites. Additional information may be
available from the review of existing data (Section 2.2.1.1) and CERCLA site
data (Section 2.2.1.2). The data from these activities will provide useful
data for the risk screening models now being developed (Section 2.2.1.7),
which in turn will be used to identify potential problems at these sites, and
for later risk, assessment. The results of initial activities will be used to
further refine Issue 3E to determine how early in the regulatory development
process it can be addressed.
Data collection efforts also include a Section 3007 survey of extraction
and beneficiation sites (Section 2.2.1.6). The design of this survey includes
specific questions regarding co-located processing operations. The results of
the survey will be used to resolve additional questions expected to be
included in the second options selection meeting. No further data collection
activities for Issue 3E are anticipated at this time.
4.5.3.6 Issue 3F: Vhich Mining Segments Should be Considered in Future
Subtitle D Rulemaking Efforts?
The mining industry includes a large number of segments in addition to
those anticipated to be covered in the initial Subtitle D program (see Table
2-3). The Agency will need to determine which of these additional segments
should be addressed in the third report to Congress and considered for future
inclusion in the Subtitle D program. The resolution of this issue will
require significant reviews of existing data and new data collection efforts
to assess the environmental and human health risks posed by these other mining
segments. These are necessary to ensure that the initial Subtitle D program
is sufficiently flexible to allow additional industry segments and wastes to
be addressed in the future.
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G/834-052-00e/#6
Data Collection Activities/Needs for Issue 3F
The review of existing data on mining operations (Section 2.2.1.1) and
CERCLA site data (Section 2.2.1.2); the risk screening model (Section
2.2.1.7); and the efforts to prepare the second and third Reports to Congress
are the major activities nov being pursued to support the resolution of
Issue 3F. These efforts will be adequate to allow inclusion in the second
report to Congress a proposed list of the industry segments to be addressed in
the third report to Congress. The results of the Section 3007 surveys
(Section 2.2.1.6) and site visits (Section 2.2.1.4) conducted in Phase II data
collection efforts will be used to determine if other industry segments should
be addressed in future Reports to Congress or, alternatively, if they should
be brought into the Subtitle D program without being addressed in a report.
4.5.4 Issue 4: What are the Technical Methodologies and Standards Needed to
Support the Rulemaking!
Mining wastes often differ significantly from the types of solid wastes
that are currently regulated under RCRA. The annual waste volumes from
several mining sites can approach or exceed that of all hazardous wastes
combined. Many mining wastes are not subject to the same conditions (e.g.,
municipal landfill environments, transportation vehicles, etc.) as other RCRA-
regulated wastes. It is not clear that sampling large heap or dump leaching
operations or large tailings impoundments using techniques now used, to sample
other RCRA wastes would characterize the mining waste adequately. These
differences and uncertainties create the need for different approaches to
measuring and controlling risks posed by these wastes. Development and/or
adoption of any new approaches must also consider the ability of the regulated
community to implement them. New assumptions may be needed for the develop-
ment of new or modified sampling and analytical techniques and pollution
control technologies.
Issue 4 involves the identification and selection of appropriate
sampling, analytical, and pollution control technologies that account for the
unique nature of some mining wastes and are not inconsistent with other RCRA
approaches. Initial resolution of Issue 4 will involve identification of
current methods and technologies that may be used or modified to meet the
needs of the current rulemaking efforts.
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June 22, 1987
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G/834-052-00e/#6
FOR U.S. GOVERNMENT
USE ONLY
Data Collection Activities/Needs for Issue 4
The main Phase I data collection activities that will support Issue 4 are
the technical issue papers (Section 2.2.1.3 and Appendices A through I) and
the initial site visits (Section 2.2.1.4). The draft technical issue papers
have led to the identification of a number of areas where new or modified
sampling and analytical techniques will be necessary. Future work, on these
papers will draw on information being developed from the review of existing
data (Section 2.2.1.1) and comments from industry and the Bureau of Mines to
develop candidate methods to resolve Issue 4. Initial site visits will be
used to compare the reliability of these and other candidate methods drawn
from the literature.
Options that are truly risk-based will be developed. These may include
options for selecting which mining wastes or management techniques will
require sampling, analytical, and pollution control techniques that are not
presently used under RCRA. Phase II data collection activities may then be
focused on developing and refining the new methodologies through additional
site visits (Section 2.2.1.4), modifications to the specific studies and
modeling efforts (Section 2.2.1.8), or the initiation of new data collection
efforts.
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APPENDICES
Page
A.
TECHNICAL
ISSUE
PAPER
1:
ACID GENERATION
A-l
B.
TECHNICAL
ISSUE
PAPER
2:
MOBILE TOXIC CONSTITUENTS - WATER
B-l
C.
TECHNICAL
ISSUE
PAPER
3:
MOBILE TOXIC CONSTITUENTS - AIR
C-l
D.
TECHNICAL
ISSUE
PAPER
4:
RADIOACTIVITY
D-l
E.
TECHNICAL
ISSUE
PAPER
5:
ASBESTOS
E-l
F.
TECHNICAL
ISSUE
PAPER
6:
CYANIDE
F-l
G.
TECHNICAL
ISSUE
PAPER
7:
DIRECT HUMAN CONTACT AND MISUSE
G-l
H.
TECHNICAL
ISSUE
PAPER
8:
CATASTROPHIC FAILURE
H-l
I.
TECHNICAL
ISSUE
PAPER
9:
COMMON TECHNICAL ISSUES
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June 22, 1987
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APPENDIX A
TECHNICAL ISSUE PAPER NO. 1
ACID GENERATION
ISSUE DEFINITION
Issue Description
The mining and processing of metallic ores are typically associated
with the generation of acid discharges. These discharges from abandoned
mines, tailings ponds, waste rock piles and overburden piles are
characterized by low pH values and high concentrations of toxic metals and
sulfate. Much of the contamination resulted from mining and disposal pro-
cesses which were acceptable practice at the time they were conducted,
prior to establishment of governmental regulations. The remnants of these
operations, some over 100 years old, continue to contribute contaminants to
surface water and ground water supplies.
Acid generation and acid mine drainage are largely the result of
oxidation of metallic sulfides. The major metallic sulfide of concern is
iron sulfide (FeS2) or pyrite. All metal sulfides and reduced mineral
species can potentially contribute to acid generation; the major metal
sulfides besides pyrite are galena (lead sulfide), sphalerite (zinc
sulfide) and chalcopyrite (iron copper sulfide).
Pyrite combines with oxygen (air) in the presence of bacteria and water
to generate sulfuric acid and iron sulfate.
The simplified chemical reaction for this process follows:
2 FeS, + 2 H,0 + 7 0, > 2 FeSO, + 2 ILSO,
2 2 2 A 2 4
(pyrite) (water) (oxygen) (iron sulfate) (sulfuric acid)
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June 22, 1987
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Another reaction that may occur involves the same reactants (pyrite,
water, and oxygen) and the formation of iron hydroxide and sulfuric acid
(Kleinmann and Crerar 1981). The iron hydroxide is associated with the
orange coating that is typically found on stream beds that have been
affected by acid drainage.
The rate of acid production is controlled by several factors. The most
important factors that affect the rate of pyrite oxidation are the size and
form of the pyrite and the presence of bacteria. Pyrite crystals that are
large and veil shaped tend to oxidize at a slower rate than small-grained
crystals of pyrite. The smaller crystals have more surface area and
reactive sites than the larger well-shaped crystals.
The presence of bacteria, especially Thiobacillus ferroxidans, in mine
waters is important because of their ability to oxidize sulfide bearing
metals. Ferroxidans are almost always present in acid mine drainages,
suggesting that they are one of the most important catalysts in acid
generation. These organisms require moisture to generate acid, but their
impact continues through most dry periods. Biological activity in the
moist areas of piles or mines forms soluble acidic salts that are released
by major precipitation events (Kleinmann and Crerar 1981).
During acid generation, the pH values of the associated waters
typically decrease to values near 2.5. These conditions result in the
dissolution of the minerals associated with the metallic sulfides and
release of toxic metals (e.g., cadmium, lead, zinc). In addition, the
concentration of dissolved anions (e.g., sulfate) also increases. The
release and impact of these toxic constituents is discussed in more detail
in Technical Issue Paper No. 2, Mobile Toxic Constituents/Water.
Pathways and Receptors
Acid generation and drainage affects ground water and surface water.
The sources of surface water contamination are drainages or leachate from
mine openings or the base of waste and tailings piles, ground water seeps,
and surface water runoff from waste rock and tailings piles. Ground water
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June 22, 1987
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is contaminated in a less direct manner than surface water. Typically,
precipitation or surface water enters mines and waste piles, reacts with
acid forming material and produces acid. These acidic waters then
percolate downward and may contaminate ground water aquifers.
The receptors of contaminated surface water are mainly humans and
aquatic organisms. Humans can be affected by direct ingestion of
contaminated surface water or direct contact through outdoor activities
such as swimming. Fish and other aquatic organisms are potentially
affected by bottom foraging and direct exposure to surface water.
Typically, the major exposure pathway is via surface water. Ground water
impacts are not as widespread as surface water impacts because of the much
slower velocity of ground water movement and the lack of available oxygen
to continue the oxidation process. Individuals with wells in a
contaminated aquifer may be exposed to contaminated waters by ingestion and
direct contact during daily activities. The contaminated ground water may
also recharge surface water supplies and affect humans and aquatic
organisms.
Site Conditions
Acid generation is a problem when the following conditions are present:
A source of acid generating materials
A pathway, usually surface or ground water, to transport
contaminants
A receptor, usually human or wildlife populations, that can be
affected by the contaminants
All three conditions must be present for a problem to exist. If one of
the three items is not present at a site or can be eliminated, the problem
may not be manifested. For example, in arid climates, the moisture
necessary for acid generation may not be present or the pathway may not
occur. In remote areas, receptors may be absent. However, because toxic
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June 22, 1987
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drainages can occur in sensitive watersheds such as the mountainous areas
of the western United States, ecosystems can be irreversibly damaged.
Assessment of the problems and selection of management practices are
usually site specific.
Example Sites
Hundreds of examples of acid drainage in mining areas exist throughout
the western United States. Two are presented here as examples of the
problem.
Zinc and other base and precious metals were produced from ores
excavated from an underground mine in central Colorado from 1878 to 1977.
The resultant wastes consist of roaster piles, tailings ponds, waste rock
piles and acid drainage from the mine. Percolation from the tailings ponds
has contaminated ground water below and downgradient of the ponds. The
ground water discharges to a nearby stream. Runoff from the roaster and
waste piles and acid drainage from the mine also discharge directly to the
stream. The main parameters of concern are pH, arsenic, cadmium, copper,
lead, manganese, nickel, and zinc. In particular, concentrations of
cadmium, copper, and zinc exceed water quality criteria in the stream. In
addition, levels of dissolved solids are also above background
concentrations. At least two private wells previously used for drinking
water have also been contaminated. The site is currently on the National
Priorities List (Superfund) and various remedial actions have been
proposed.
An example of ground water contamination by acid generation is a
tailings pond in a mining district in Idaho. Seepage from the pond has
entered the ground water system. Upgradient of the tailings pond, the pH
is about 6.0 due to other mining activity in the area. Seepage from the
pond has caused a decrease in pH to 4.3 at a distance of more than two
miles downgradient of the pond. Metals associated with the seepage also
exceed water quality criteria (EPA 1976).
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June 22, 1987
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ISSUE IDENTIFICATION AND SOLUTIONS
Characterization and Analysis
Much of our knowledge of acid generation is derived from experience in
the coal mining regions of the eastern United States. In this area, pyrite
is the precursor of acid mine drainage. However, the mechanism, processes
and reasons why some coal mining sites produced acidic discharges while
others did not were not well understood. The depositional environment of
the pyrite has been identified as the critical factor governing the rate of
acid production in coal deposits (EPA 1977). The pyrites in the western
mining.areas are formed by igneous and metamorphic activity, rather than
the sedimentary nature of the eastern coal pyrites. Therefore, the
chemical characteristics of the pyrites may be different.
To assess the potential for acid production, chemical analyses can be
performed using coal characterization techniques. The primary analytical
techniques used to assess the potential of waste rock, tailings, slimes,
etc. to produce acid are as follows (Caruccio and Geidel 1984):
Neutralization potential
Acid-producing potential
Total sulfur
Pyritic sulfur
Electrical conductivity on waste/water mixtures
..pH on waste/water mixtures
Batch tests
Column leach tests
The neutralization potential and acid producing potential, when
combined, measure the overall acid/base potential of a solid. If the waste
has an excess acid potential, the material may create acid under field
A-5
June 22, 1987
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conditions when contacted by water. If the material has an excess base or
neutralization potential, an alkaline or neutral discharge is likely to
result.
Several methods are used to determine potential acidity. One is
reaction with hydrogen peroxide, which oxidizes all reduced mineral
species. The acidity produced is then measured. In another method, the
potential acidity is calculated from the pyritic sulfur content. The
calculations are based on stoichiometric reactions of pyrite with oxygen
and water. This may, however, be an overestimation of acid production
since all pyritic sulfur may not react to produce acid.
Electrical conductivity (EC) and pH tests are performed on mixtures of
rock and water. The purpose of the test is to determine the potential to
generate acid (pH) and increase dissolved solids concentrations (measured
by electrical conductivity).
Batch and column leach tests are among the best methods of predicting
if a rock type or waste may produce acid. In column tests, rock, waste, or
tailings are placed in a column and contacted with water or moist air.
Water is then collected and analyzed for pH and other selected constituents
(Caruccio and Geidel 1984). The column leach tests are the most expensive
tests to perform; however, they are also probably the most accurate in
predicting drainage quality.
Prediction of Acid Generation
The analytical methods discussed above are used to predict acid
generation potential. One approach in evaluating the potential of a site
to produce acid is to use a three-tiered sampling and analytical testing
program. The first analysis tier employs field testing to determine if
acid production is possible. This can be accomplished by performing field
EC and pH tests. Samples that have low pH values based on field tests are
then submitted to the laboratory for acid/base potential analyses. If
these samples also indicate an acid generation potential, batch or column
leach tests may be utilized to predict quality.
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June 22, 1987
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Currently the best prediction methodology available for the acid
generation potential of a waste is the column leach tests or a variant of
these tests. One of the best current techniques in the coal industry is
the use of columns packed with soil obtained from drilling programs at mine1
sites. Warm moist air is passed through the columns for a designated
period of time. This process provides the pyrite, bacteria, oxygen and
water to speed up the acid generation reactions. The columns are then
flushed with water that is collected for analysis or recycled again. When
the subsequent flushings appear to be in equilibrium with the packed column
material, the effluent is judged to be the best prediction of water quality
during and after mining.
Site-specific factors should also be considered in the analyses. For.
example, if evaluations using site data indicate that no percolation of
water will occur through a waste pile, then column or batch tests would not
be necessary.
Management Controls
The most effective management control for a site is determined by the
waste characteristics, site hydrogeology, transport pathways, receptors and
available resources. Numerous control technologies for acid generation
exist. The following are three general types of controls:
Pretreatment to prevent acid generation
Containment of acid-forming materials
Controlled release and subsequent treatment
Pretreatment controls may include abatement of the source by isolating
pyrite or prohibiting contact with water and air. For example, mine adits
can be plugged to prevent discharge or the workings can be filled with low
density concrete or grout. This technique may not be totally effective
because the water may exit at other locations. Other pretreatment
techniques include:
A-7
June 22, 1987
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Adding chemicals (e.g., detergents) to reduce biological activity
Reprocessing of waste rock or tailings to eliminate sulfide-bearing
materials
Burial of waste materials below the water table to prevent sulfide
oxidation
Examples of containment options include:
Secure land burial to encapsulate the waste
Capping to seal off infiltration and air
Solidification with a lime-rich material to neutralize future acid
production and stabilize metals
The last category of control techniques is the controlled release of
leachate or discharge and subsequent treatment. Treatment may include
addition of a neutralization agent (e.g., lime) to precipitate the metals.
To prevent acid generation at proposed mines and mills, a waste
management and mining control plan should be developed for sites with acid
generation potential. These plans should address the prevention,
elimination or significant reduction of acid generation. At sites where
acid production is a potential and pathways/receptors are present, more
stringent controls may be necessary.
Verification and Monitoring
Currently, there are few established design standards or requirements
for closure of non-coal mines and mine waste sites. Requirements or
standards for management controls during operation vary from State to
State. Whether the waste is encapsulated or backfilled, monitoring of the
ground water, surface water, and disposal site may be desired to verify the
integrity of the controls in place. In addition, maintenance of the
facility, such as upkeep of a vegetative cover over a disposal site or
upkeep of a treatment process, may be required.
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June 22, 1987
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ADEQUACY OF EXISTING INFORMATION AND RECOMMENDED REGULATORY SUPPORT
ACTIVITIES
Adequacy of Existing Information
Although extensive data exist concerning environmental impacts
of mining of metallic ores, little information exists that integrates
sources, pathways, receptors, and risks. If the regulatory program is
based on a risk, approach, this type of integration of the data needs to be
performed. In some areas (e.g., receptor exposure), limited data are
available and additional information will be needed.
Limited information also exists concerning the mechanisms controlling
acid drainage from hard rock mines in the western United States. The
methodology used to predict acid generation from wastes generated during
mining is also not adequately developed.
Recommended Regulatory Support Activities
Based on a preliminary review of current data, the following activities
are recommended:
Integration of data in a risk based format
Formalization of a risk assessment methodology
Development of analytical techniques to predict acid generation
potential
Development of techniques to predict leachate water quality
Once the methodologies are developed and formalized, a test case should
be evaluated in which the predicted affects are compared to actual results.
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June 22, 1987
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SUMMARY AND RECOMMENDATIONS
The mining and processing of metallic ores has resulted in the
degradation of surface vater and ground water supplies. One of the major
causes of this contamination is acid generation, which results from the
oxidation of sulfide bearing minerals, of which pyrite is the most
significant. In particular, the sulfide mineral reacts with water and
oxygen in the presence of bacteria to produce sulfuric acid and iron
hydroxide or iron sulfate. The low pH values result in the dissolution of
minerals and the release of toxic metals and other constituents (e.g.,
sulfate).
Acid generation can result in detrimental impacts to human health and
the environment if the following three conditions are present at a site:
A source of acid generation and release of toxic constituents
A pathway, usually surface or ground water, to transport the toxic
constituents
A receptor, usually human or aquatic life, resulting in exposure
If one of the three items can be controlled or eliminated, the problem
may not be manifested. Therefore, the assessment of the problem and
resultant management controls must be site specific. Management controls
may include "pretreatment" to eliminate the source, containment and/or
controlled release with subsequent treatment. Pretreatment techniques
include plugging of mine adits and burial of waste below the water table.
Both of these techniques prevent oxidation of the sulfide minerals, thus
eliminating the source. Containment techniques such as capping to
eliminate infiltration remove the transportation pathway. Under all
management scenarios, verification and monitoring are possible
requirements.
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June 22, 1987
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Although extensive data exist concerning environmental impacts
associated with mining of metallic ores, limited information is available
that integrates sources, pathways, receptors, and potential risks. The
following activities are recommended to support technical understanding of
the environmental impacts of acid generation:
Integration of data necessary to evaluate potential impacts on human
health and the environment
Risk assessment methods for mining sites
Analytical techniques to predict acid generation potential
Techniques to predict leachate water quality
REFERENCES
Caruccio, F.T. and Geidel, G. 1984. Applicability of Overburden Analytical
Techniques in the Prediction of Acid Drainages.
Kleinmann, R.L. Crerar, D.A., and Pacelli, R.R. 1981. Biogeochemistry of
Acid Mine Drainage and a Method to Control Acid Formation. Mining
Engineering. March, pp. 300-304.
Sobek, A.A., Schuller, V.A., Freeman, J.R., and Smith, R.M. 1978. Field and
Laboratory Methods Applicable to Overburden and Mine Spoils.
EPA-600/2-78-054.
U.S. Environmental Protection Agency. 1976. Water Pollution Caused by
Inactive Ore and Mineral Mines - A National Assessment.
EPA-600-17-76-298. 195 p.
U.S. Environmental Protection Agency. 1977. Paleoenvironment of Coal and
its Relation to Drainage Quality. EPA-600/7-77-067. 195 p.
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June 22, 1987
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APPENDIX B
TECHNICAL ISSUES PAPER NO. 2
MOBILE TOXIC CONSTITUENTS/WATER
ISSUE DEFINITION
Issue Description
In a survey conducted in the mid-1970's, EPA determined that contami-
nation from inactive ore and mineral mines has affected more than a
thousand miles of streams and rivers in the western United States. More
than 10,000 tons of metals were estimated to discharge annually to these
streams and rivers (EPA 1976). Many of the streams contained metal
concentrations that exceeded water quality criteria and posed a risk to
human health and the environment. Although metals are the predominant
constituents released, other nonmetal constituents are potentially mobile,
such as CN" and F~. In addition, many of the mining sites had contaminated
ground water.
Several mechanisms are responsible for the release of metals to surface
and ground waters. The release of metals typically results from a change
in the physical and chemical environment in which the minerals were
originally deposited. For example, mining operations are responsible for
exposing metal sulfide minerals, most notably pyrite (FeS2), to oxygen and
water. The combination of oxygen, water, and metal sulfides in the
presence of bacteria results in acid production and subsequent release of
metals. These acidic waters are then capable of solubilizing additional
metals. The mechanism of and impact from acid production is discussed in
Technical Issue Paper No. 1, Acid Generation. Metals potentially found at
elevated concentrations in surface water and ground water near mining
facilities with acid generation problems include but are not limited to the
following:
Aluminum
Arsenic
Cadmium
Chromium
Copper
Lead
Manganese
Mercury
Nickel
Selenium
Silver
Uranium
Zinc
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June 22, 1987
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In addition, the waters typically have elevated concentrations of
dissolved anions, sulfate and in some instances, fluoride.
Not all mobile toxic constituents are associated with the production of
acid and subsequent dissolution of metals. Physical and chemical changes
during mining can also result in the release of metals without acid
production. For example, arsenic is typically associated with ore minerals
as a reduced sulfide mineral. If conditions are changed from a highly
reducing environment which occurred during sulfide ore deposition to mildly
reducing conditions, the arsenic can become solubilized without acid
production. In particular, the arsenic will exist in solution as the
arsenic (III) species (H3As03) which is very mobile in water and highly
toxic. Selenium and chromium may also be released to the environment under
some non-acidic conditions.
In addition to the physical and chemical changes caused by mining or
milling discussed above, chemicals may also be introduced during the
processing of the ores. Chemical compounds of zinc, mercury, and copper,
and acid, cyanide, and other potential contaminants are used to leach,
separate, froth, or amalgamate ores.
Pathways and Receptors
Toxic metals and other constituents in water migrate via both the
ground water and surface water pathways. When toxic constituents become
dissolved species, they are able to enter the ground water and/or surface
water. In solution, the constituents can either remain dissolved or they
can undergo physical/chemical changes such as adsorption or precipitation.
If the constituents remain in solution under the right physio-chemical
conditions, they can be transported miles from where they entered the
surface regime. The constituents (especially the metals) can also
precipitate or adsorb from solution and collect on the stream bottom or
aquifer material.
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June 22, 1987
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When toxic constituents are transported by either surface or ground
vater pathways, the major potential receptors are human and aquatic life.
The receptors can be exposed to the toxic constituents in either the
solubilized or the adsorbed/precipitated form. Human receptors can be
exposed to mobile toxic constituents that are in solution through vater
intakes that are downstream of mine or mine waste discharges. In this
case, ingestion of and direct exposure to the contaminated waters can
occur. Humans can also be exposed by direct contact and ingestion through
recreational activities such as swimming and boating. Another potential
means of exposure to humans is through the ingestion of fish from
contaminated waters. Aquatic life can bioaccumulate and concentrate
metals. Humans that ingest these aquatic life are exposed to the metals.
Aquatic life can be exposed to both dissolved and adsorbed metals.
Metals in solution are passed through the gills of fish and can be absorbed
into their blood and tissues. Fish, particularly bottom feeders, can also
be exposed to metals by feeding on plants and bottom life that have
coatings of adsorbed/precipitated metal complexes.
The ground water pathway can also result in exposure of receptor
populations. The dissolved mobile toxic constituents can flow through
fractures, pore spaces, and mine workings until they reach an aquifer.
If the physical and chemical conditions of the system are conducive to
maintaining the constituents as dissolved species, they can be transported
through the aquifer. Water flow velocities in aquifer systems are
typically much slower than, in the surface water systems. Therefore
velocity of the constituents (especially metals) is also slower. The
receptors of the mobile toxic constituents in ground water are predomi-
nantly humans that have wells in the contaminated aquifer. Exposure is
through direct contact and ingestion.
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June 22, 1987
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Site Conditions
As discussed above, mobile toxic constituents are most obviously a
problem when a receptor population is exposed. Therefore, for a problem to
exist, the constituents must be toxic and mobile, a pathway must be
present, and a receptor must be exposed. Usually the exposed populations
are human and aquatic life; however, because toxic drainage can occur in
sensitive watersheds such as the mountainous areas of the western United
States, ecosystems can be irreversibly damaged. The three conditions
(mobile toxic constituents, pathways, and receptors) do not exist at all
mining sites. For example, in arid climates with low precipitation and
infiltration, acid generation may not occur or, if acid production does
occur, water pathways may not be present. In other remote areas, the
receptors are not present. Therefore, in evaluating the potential effects
of mining on the environment, site-specific information must be considered.
Example Sites
There are numerous abandoned and active mining sites that have toxic
drainages. These sites range in size from small one-man mining claims on
the sides of remote mountains to large tunnels that discharge thousands of
gallons of contaminated water per minute. The threat to human health and
the environment has warranted the placement of over 40 mining waste or
mining waste related sites on the National Priorities List (NPL).
One of these NPL sites is in the mountains of Colorado. At this site, five
sources have been identified as contributors to the degradation of two
mountainous streams. These sources include mine portals/tunnels, waste
rock and tailings piles. Preliminary investigations have identified the
following as some of the potential metals of concern:
Aluminum
Arsenic
Cadmium
Chromium
Copper
Lead
Nickel
Silver
Zinc
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June 22, 1987
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In addition, dissolved anions such as fluoride and sulfate have been
identified as constituents of concern. This site presents predominantly a
surface water problem with potential receptors including a city vith a
water intake downstream of the site. The receiving streams are also used
for fishing and recreation. However, the aquatic population is severely
limited because of the high metal concentrations. Ground water
contamination has also been identified, however, the extent of contamina-
tion and potential receptors are not currently known.
Another NPL site is located in central Montana. At this site, tailings
from copper production have been deposited behind a dam on a river. Under
these conditions, a mildly reducing, non-acidic environment has been
created in which arsenic becomes highly mobile. The infiltrating water
from the impoundment behind the dam leached the arsenic into the ground
water, contaminating nearby residential wells.
ADDRESSING THE PROBLEM
Characterization and Analysis
Toxic constituent mobilization in ground water and surface water is
primarily characterized by chemical analyses of the potentially impacted
water systems. The analytical techniques for the metals are well
established and include atomic absorption (AA) and inductively coupled
atomic emission spectroscopy (ICP). However, many methods of sample
collection, preservation, and preparation for the metals are currently
used, including the following (Colo. Dept. of Health 1976):
Total Metals - The water sample is collected, placed in a sample bottle
and acidified to a pH of less than 2.0. At the laboratory, various
digestion techniques are used depending upon the specified procedures.
If all the sediment is to be dissolved, hydrofluoric acid is used with
vigorous digestion. Other digestion techniques typically do not
dissolve all the sediments (e.g., silicate minerals) but are still
referred to as total concentrations.
Total Recoverable Metals - The water sample is collected, acidified
with a dilute acid solution in order to dissolve only the readily
soluble fraction. A vigorous digestion is not performed in the
laboratory.
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Potentially Dissolved (Acid-Soluble) Metals - Water samples are
collected, preserved with nitric or similar acid and let stand for 8 to
96 hours. The sample is then filtered in the laboratory through a 0.45
micron filter before analysis.
Dissolved Metals - Water samples are filtered through a 0.45 micron
filter in the field and then acidified for preservation. This
technique eliminates suspended and most colloidal sediment.
As observed, the techniques described above solubilize different
amounts of the suspended material in the samples. The amount dissolved
decreases following the order listed above. The various techniques were
proposed to represent the amount of material that is biologically available
to aquatic organisms. Typically, in surface water at least two analyses
are performed: dissolved metals and one of the "total" methods.
The solids at mine sites (waste rock, tailings, sediments, and soils)
are characterized by techniques developed in the soil science, mining,
geochemical and environmental fields. The most common analysis performed
on solid samples is for "total" metals content. Typically, digestion or
fusion techniques are used to dissolve the solids into a liquid phase
before analyses. Most metals above an atomic number of 10 can also be
determined through nondestructive techniques such as.X-ray fluorescence
(XRF). In addition to analyzing for "total" metal content, solid samples
are evaluated for their potential to release metals under various
conditions. Techniques used to predict metal leachability include batch
shaker tests and column tests. To date there is no standard agreement on
the techniques to be used and the methods to predict mobilization. Various
methods of sample preparation of solid samples also exist, including
rigorous crushing and grinding prior to analysis, screening followed by
some grinding, and analysis without sample preparation.
Prediction
Once a problem is identified, characterization of the ground water,
surface water and waste must be completed. These characterization studies
include the analysis of the chemical constituents discussed above. The
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site must also be characterized with respect to environmental setting,
hydrologic regime, meteorologic conditions, etc. These newly acquired data
are then used in conjunction with historic data to predict the future
extent of the problem. Typically, this prediction is performed through the
use of computer-generated models. Two general classes of models exist:
geochemical and hydrological.
Geochemical computer models used successfully at mining sites include
MINTEQ (Felmy et al. 1983) and PHREEQE (Parkhurst et al. 1980). These
programs are thermodynamic based models that are used to predict the
concentrations and species present at equilibrium. The codes are first
calibrated to the existing conditions. By changing existing conditions
through the elimination, increase, or reduction of sources or the change of
pH and oxidation/reduction potential, the resulting dissolution, dilution,
adsorption, or precipitation of the toxic constituents can be determined.
These analyses are extremely important in evaluating the effects of waste
management options on potential receptors.
Typically, the geochemical programs are used in conjunction with ground
water or surface water programs. Models are calibrated based on data
obtained from ground water monitoring wells and surface water monitoring
stations. The models are then used to simulate or predict ground water or
surface water quality changes with time for the no action option or a host
of other alternatives such as source control, seepage collection, dilution,
controlled release, or discharge treatment.
One of the greatest uncertainties in predicting water quality is the
amount of metals and other constituents that will be mobilized and their
subsequent fate and transport. Currently, the best method of evaluating
the mobilization and fate is through the use of column or batch tests.
Column tests consist of packing columns with solids such as waste rock,
tailings, and passing water (precipitation, ground water or distilled
water) through the column. The water that passes through the column is
analyzed when equilibrium concentrations are reached. This equilibrium
concentration of constituents is then assumed to be the estimate of the
discharge quality from the site; i.e., the source concentration. Likewise,
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once the source term (or amount of constituents mobilized) is determined,
the subsequent interaction of the chemical constituents with river
sediments or aquifer material is usually determined through the use of
additional batch or column tests. These tests are typically used to
determine the distribution of the chemical constituent between the solid
and aqueous phases. This distribution coefficient is then used in the
hydrological models. To date, research is lacking on the accuracy of these
tests at metal mining sites. Comparisons between laboratory test concen-
trations and existing concentrations must be made to determine if
laboratory leach tests are reliable for predicting mine and mine waste dis-
charges and the subsequent fate and transport of the metals and other
chemical constituents.
Controls
Numerous control technologies for metal mobilization and increased
dissolved solids concentrations,exist. Controls range from perpetual
treatment of the discharge to abatement of the source by isolating pyrite
and other metallic sulfide's from contact with oxygen, water, and air.
Mine adits can be plugged to prevent discharge or the workings can be
filled with low density concrete or grout. These techniques are not always
effective because the water may discharge at other locations. Tailings
piles and waste rock can be managed by several options. These include:
Secure land burial to encapsulate the waste
Capping to seal off percolation and air
Leachate collection and subsequent treatment
Reprocessing to eliminate sulfide bearing materials
Solidification with a lime-rich material to neutralize future acid
production and stabilize metals
The management controls to be used at any site are largely a function
of the site geology, waste characteristics, hydrogeology, receptors and
available resources.
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To prevent the problem of toxic constituent mobilization and increases of
dissolved solids at future mines and mills, a vaste management and mining
control plan should be developed for sites with potential toxic constituent
mobilization. At sites where acid production and toxic constituent
mobilization is a potential and pathways and receptors exist, control
measures may be necessary.
Leaching of toxic constituents from tailings impoundments can be
controlled by a number of methods. One option is to encapsulate or contain
the waste. Another option is to collect, treat, and return leachates to
the impoundments. Waste rock can also be managed to prevent or reduce
metal mobilization. Vaste rock that has metal leaching potential can be
buried beneath the water table to prevent sulfide oxidation. The acid
producing rock may also be mixed with alkaline materials to improve the
water quality of drainages and keep metals in a solid form.
Verification and Monitoring
The exact monitoring and verification requirements depend upon the
specific site conditions and ultimate closure requirements. Regardless of
the management alternative selected, long-term monitoring of ground water,
surface water, and the disposal site is recommended. In addition,
maintenance of the facility, whether it includes upkeep of a vegetative
cover over a disposal site or upkeep of a treatment process, may be
required. In all cases, the requirements of closure and monitoring should
be site-specific depending upon the environmental conditions, pathways
present, potential receptors, and potential risks.
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ADEQUACY OF EXISTING INFORMATION AND RECOMMENDED REGULATORY
SUPPORT ACTIVITIES
Adequacy of Existing Information
Currently, a large quantity of data exists concerning mining sites.
However, the methods used to collect and analyze the data have not been
consistent among sites. In addition, data have been collected on only a
few sites with the emphasis on assessment of pathways, receptors, and risk;
these typically have been NPL sites. Most existing data address the actual
chemical composition of wastes; however, little information exists on the
evaluation of these wastes and prediction of potential environmental
problems. Prediction methodology has not been consistent. Few examples
exist in which actual post-modeling data have been re-evaluated to
determine the accuracy of the models.
Recommended Regulatory Support Activities
Consistent and standardized procedures need to be developed for the
chemical analyses of both water and solid matrices. The analyses of water
should emphasize techniques to simulate bio-available metals. The analyses
of solids should emphasize the leachability of the metals. Column and
batch tests should be standardized to emphasize metal fate and transport.
Once the source terms and potential interactions are characterized,
prediction techniques should be used. These techniques should also be
standardized, although some latitude and professional judgment will be
necessary when using models. This judgment is necessary because the models
should be site-specific.
Once the analytical techniques and prediction methodologies are agreed
upon, several sites should be evaluated using the selected methods. This
will include, in some cases, collection of site-specific data. In all
cases, the predicted impacts should be compared to observed conditions.
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SUMMARY AND RECOMMENDATIONS
During the mining and milling process, physical and chemical changes
can result in the release of toxic constituents to ground and surface
waters. A major mechanism for the release is when metallic sulfide
minerals are exposed to oxygen, water, and bacteria. Under these
conditions, the minerals are oxidized and produce acid, resulting in the
subsequent dissolution of metals and production of sulfate. Changes in
oxidizing conditions can also mobilize metals without the production of
acid.
Once the toxic constituents are released in the dissolved form, they
can be transported in both ground and surface waters. In these regimes,
the constituents may undergo further reactions such as adsorption or
precipitation. The exact transport and fate of the constituents is
site-specific. In all cases, the ultimate concern is the exposure of
receptor populations. That is, a potential pathway to a receptor (human or
aquatic life) and potential risk must exist. This evaluation also requires
site-specific information.
The analytical methods used to characterize ground and surface water
constituents are well established. However, many different techniques are
used to dissolve the solid samples and the solid portions of liquid
samples. These techniques range from total solubilization techniques to
bio-available techniques. Likewise, a large variety of leach tests exist
to determine the quantities of toxic constituents actually released from
the solid materials. Once the sources have been characterized, a variety
of impact prediction methodologies also exists. Typically, geochemical and
hydrological computer models are used.
Management techniques used to eliminate or control the release of toxic
constituents to ground and surface waters vary widely. Options include
encapsulation/containment of tailings and waste rock, controlled release of
discharges, treatment of discharges, capture and return of discharges,
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plugging of adits, and solidification of solids vith alkaline materials.
The effectiveness of these management controls depends upon the site
conditions and potential pathways and receptors.
Consistent and standardized analytical procedures are needed to
characterize samples from mining sites. Procedures should include:
Techniques for crushing/grinding and sample preparation
Techniques for dissolving solid samples and the solid portion of
liquid samples
Tests to determine the quantity of metals leached from solid
samples
Tests to determine the fate and transport of the dissolved metals in
ground water and surface water regimes
Dissolution techniques should emphasize methods that simulate bio-
available concentrations and leaching under actual site conditions.
Once the toxic constituent source concentration is determined, the
potential impact of the constituents on the environment should be evaluated
and predicted. Geochemical .and hydrological models should be used.
Although the models should be consistent, some professional judgment will
be necessary to allow for site-specific conditions.
Once the characterization techniques and prediction methodologies have
been determined and standardized, several sites should be evaluated using
the selected procedures.
REFERENCES
Colorado Department of Health. 1976. Final Report of the Water Quality
Standards and Methodologies Committee to the Colorado Water Quality
Control Commission. June.
Felmy, A.R.; Girvin, D.C. ; and Jenne, E.A. 1983. MINTEQ - A Computer
Program for Calculating Aqueous Geochemical Equilibria. Final Project
Report. EPA Contract 68-03-3089.
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Parkhurst, D.L.; Thorstenson, D.C.; Plummer, L.N. 1980. PHREEQE - A
Computer Program for Geochemical Calculations. U.S.G.S. Water Resources
Investigation 80-96.
U.S. Environmental Protection Agency (EPA). 1976. Water Pollution Caused by
Inactive Ore and Mineral Mines - A National Assessment. EPA 600/2-76-298.
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APPENDIX C
TECHNICAL ISSUE PAPER NO. 3
MOBILE TOXIC CONSTITUENTS/AIR
ISSUE DEFINITION
Issue Description, Pathvays, and Receptors
Active and past mining operations contribute to airborne toxic metals
and other constituents. Exposures have been documented from Superfund
sites, proving that airborne toxic metals can be a major concern to
receptor populations. Active mining operations release metals-contaminated
dust from mining, smelting process, and waste disposal practices.
Uncontained vaste disposal sites from past mining operations are also
sources of airborne toxic constituents.
Active Mining Operations
The mining of metallic ores, the processing and production of a
concentrate, and ore roasting and smelting operations may introduce toxic
metals and other constituents into the atmosphere {EPA 1983). These
processes may also result in the generation of byproducts and vaste
materials that also may become sources for airborne toxic constituents.
Processing of ores to free the metallic minerals results in particulate
emissions to the atmosphere. The major processing steps and sources that
contribute to these emissions include blasting, shoveling, loading, road
hauling, crushing, dry and vet grinding, screening, concentrating, stock
piling, waste piling, and tailings impoundment.
The ore roasting and smelting operations emit toxic constituents to the
atmosphere via stack, and fugitive emissions. Smelting byproduct materials,
such as slag, are secondary sources for the release of toxic metals into
the atmosphere (EPA 1984).
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The most common mechanisms for releasing toxic constituents into the
environment from these processes, in addition to stack and fugitive
emissions, include dry and wet deposition, entrainment by vehicles on haul
roads, and windblown material from stock piles, waste piles, and tailings
ponds (EPA 1983).
Past Mining Operations
Mill tailings and flue dusts are two primary sources of mobile toxic
constituents in the air. Mill tailings, which account for one-third of
mining wastes, are waste materials remaining after physical or chemical
beneficiation operations remove the valuable constituents from the ore.
The tailings leave the mill as a slurry consisting of 50 to 70 percent
liquid mill effluent and 30 to 50 percent solids (clay, silt, and sand-
sized particles)(EPA 1982a). Tailings are usually disposed of in tailings
ponds. Improper past waste disposal (e.g., no protective covering) allows
the tailings to be exposed to erosion and thus the potential for air
transport.
Flue dusts are very fine dusts which are separated from the flue gas in
the smelting process and which are often extremely high in metal content.
Due to the small particle size (compared to waste rock), these contaminants
are highly susceptible to wind transport if not properly contained.
Site Conditions
Receptor populations that might be exposed to airborne toxic
constituents could be the mining personnel and nearby residential
populations. Livestock, crops, or sensitive environmental areas are other
possible receptors. Exposure can occur through inhalation and/or
ingestion. Exposure by inhalation can result from the airborne toxic
constituents or resuspension of household dusts and road dusts. Exposure
by ingestion can result from children's outdoor activities (consumption of
soils), ingestion of contaminated food crops, or ingestion of contaminated
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livestock. For actual adverse effects to occur, there must be a source of
toxic constituents, an air pathway, and a receptor population. Because
these conditions vary from site to site, the evaluation of potential
effects and control options must be site specific.
Example Sites
National Priorities List (NPL) Superfund sites provide excellent
examples of airborne toxic constituent contamination. Tvo sites are
briefly discussed below, and a third site is examined in more detail.
At an active lead smelter in central Montana, toxic metals (lead) in
air emissions have resulted in numerous cases of miscarriages in cattle.
At an inactive facility in Idaho that smelted lead, zinc, and copper
ores, windblown tailings had been collected by citizens for use in gardens.
When the State became aware of this, it ordered the company to provide dust
suppression on the tailing piles and ponds.
At an abandoned copper smelting facility in western Montana, fugitive
dust emissions from numerous flue dust storage areas, along with stack
emissions from the facility's prior operations, had contaminated a small
community with elevated levels of arsenic, cadmium, lead, and copper.
Onsite flue dust metal concentrations were arsenic - 69,000 mg/Kg; cadmium
- 1,300 mg/Kg; lead - 14,000 mg/Kg; and copper - 86,000 mg/Kg.
Corresponding highest metal concentrations in offsite soils were arsenic -
3,350 mg/Kg; cadmium - 101 mg/Kg; lead - 2,150 mg/Kg; and copper - 6,125
mg/Kg. Levels of contaminants decreased with distance from the flue dust
storage area. Household dust samples also indicated metal concentration
similar to contaminated levels found in the homes yards.
The Centers for Disease Control conducted surveys in the community and
discovered elevated levels of arsenic in children's (aged 2-6 years) urine.
This was attributed to that age group's tendency to ingest soil. Cancer
risk assessments were conducted for arsenic and the other metals of
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concern. The results showed a 10~3 excess cancer risk (1 excess cancer
death in 1,000 people) for ingestion of arsenic by children and a 10~5
excess cancer risk for inhalation of arsenic by adults.
The flue dust storage area has now been stabilized, so the majority of
airborne metal contaminants have been eliminated. Resuspension of metal
contaminants in the soils and along roadways is still a potential problem
for the community, as is ingestion of soils by children.
ISSUE IDENTIFICATION AND SOLUTIONS
Characterization, Analysis, and Prediction
Volumes and toxicity profiles of wastes are the initial step in
characterization of an airborne toxic metal problem. Large waste volumes
may not be a significant problem if the waste has low toxicities and/or the
particular metal of concern is not biologically available to the receptor
population. The air pathway can be significant for fine flue dusts
containing toxic constituents and dusts from mining operations and roads.
The receptor population could be humans, animals, or environmentally
sensitive areas.
High volume air sampling stations between the source of the
contamination and the receptor population should be at varying distances
from the waste source in order to determine how far the toxic constituents
are migrating (EPA 1983). Also, samplers within the receptor populations
need to be in the same respirable range as the population. Filters removed
from the samplers are then analyzed for the constituents of concern and for
particle size.
Geographic areas with high precipitation will be less of a problem than
arid regions where particulates will be more easily transported by the
wind. The location of the waste piles and the direction of the prevailing
winds also are significant factors in determining if there is a pathway to
the receptor population.
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Risk assessment is the most effective method of predicting an airborne
toxic constituent problem. Once sampling data have been reviewed (from air
and soils), risk predictions can be established for the receptor
population. Based on assumptions such as inhalation rates by adults and
children, ingestion amounts by children, respirable sizes of particles,
etc., and on analytical results, risk can be determined. This
determination predicts excess cancer risk over a lifetime. It should be
noted that levels of metals could also cause acutely toxic effects.
Management Controls and Monitoring
The mining industry is regulated under the Clean Air Act to ensure that
fugitive emissions are controlled during processing operations (Proposed
National Emissions Standards for Hazardous Air Pollutants) (EPA 1982a).
Preventive measures to assure that waste piles do not create a pollution
problem may include locating waste disposal areas where the pathway to the
receptor is disrupted. Methods such as wetting waste piles to control
fugitive dust are relatively ineffective and require continuous operations.
Chemical dust suppressants are more effective than wetting, but even these
that bind the small dust particles into a crust-like material require
continuous monitoring. Enclosure of the waste piles appears to be most
effective in preventing release of dusts, but is expensive and may not be
practical for all operations. Other controls include revegetation and
physical stabilization (e.g., covering with rock) (EPA 1982b, EPA 1977).
In addition, mining companies may find it profitable to reprocess the
materials and extract the toxic compounds from the waste materials.
Controls must be verified and monitored on closure. This can be
accomplished by visual observations, but high volume air samplers between
the contaminant source and the potential receptor population to measure
offsite contaminant migration are more effective (EPA 1977).
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ADEQUACY OF EXISTING INFORMATION AND RECOMMENDED REGULATORY SUPPORT
ACTIVITIES
Adequacy of Existing Information
Because of Federal and State regulations, current information on air
emission standards and emission control devices are adequate for active
mining operations. Extensive research and testing have assured that
pollution control devices are effective in the prevention of airborne
releases of toxic constituents (EPA 1984). Existing information on air
sampling devices and laboratory analysis of the collected samples are also
extensive and adequate.
However, information on waste piles (e.g., fugitive dust emissions)
from both active and inactive facilities is inadequate. Monitoring of the
waste piles is necessary to determine whether additional controls are
needed.
Recommended Regulatory Support Activities
Most states have regulations addressing fugitive air emissions, but
these regulations are not consistent from State to State. Also, these
regulations are based on active facilities and do not specifically address
waste products and inactive facilities.
Consistent regulations are needed to prevent or control fugitive emissions
from waste disposal. In support of the regulatory process, the following
activities are recommended:
Recommended controls on waste piles and verification of the
effectiveness of these controls (air sampling)
Utilization of modeling to predict airborne pathway releases
Utilization of risk, assessments to determine potential health
effects
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SUMMARY AND RECOMMENDATIONS
Mining operations, both active and past, contribute to airborne toxic
constituents. Active mining operations release contaminated dust from
mining, smelting process, and waste disposal practices. Improper waste
disposal at past mining operations are sources of airborne toxic
constituents.
Mining wastes and airborne emissions from facilities are cause for
concern when there are toxic contaminants, a pathway (in this case, air),
and a receptor population. Waste characterization and air monitoring
stations are necessary first steps to determine the potential for exposure
to the receptor population. Site-specific data must also be considered;
for example, the location of the waste piles and meteorological factors.
Once the source concentrations, pathways, and receptors are determined,
risk assessment based on site-specific data can be used to determine
whether a potential adverse affect exists.
Current regulations (Federal and State) assure that fugitive emissions
are controlled during processing operations. However, regulation of
non-process sources, such as waste piles or resuspension by vehicular
activity, at active or inactive facilities, are either not in effect or are
not consistent from State to State. Regulations may need to address waste
disposal, controls on waste, and monitoring the effectiveness of the waste
controls. Examples of controls on waste piles include, but are not limited
to, wetting, chemical fixation, enclosure, and physical stabilization.
Monitoring the adequacy of these controls can be accomplished by high
volume air samplers located between the waste source and the potential
receptor population.
Consistent regulations to prevent fugitive emissions from waste
disposal are recommended. In support of the regulatory process, the
following activities are recommended:
Recommended controls on waste piles and verification of the
effectiveness of these controls (air sampling)
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Utilization of modeling to predict airborne pathway releases
Utilization of risk assessments to determine potential health
effects
REFERENCES
U.S. Environmental Protection Agency (EPA). Office of Air Quality Planning.
1977. Technical Guidance for Control of Industrial Process Fugitive
Particulate Emissions. Research Triangle Park, North Carolina. EPA
450/3-77-010. March.
U.S. Environmental Protection Agency (EPA). Office of Air Quality Planning.
1982. Metallic Material Processing Plant Background Information for
Proposed Standards. Volumes 1 and 2. Research Triangle Park, North
Carolina. EPA 450/3-81-009a. August.
U.S. Environmental Protection Agency (EPA). Office of Air Quality Planning.
1982. Control Techniques for Particulate Emissions from Stationary
Sources. Volumes 1 and 2. Research Triangle Park, North Carolina. EPA
450/3-81-005a. September.
U.S. Environmental Protection Agency (EPA). Office of Air Quality Planning.
1983. Inorganic Arsenic Emissions from High Arsenic Primary Copper
Smelters. Background Information for Proposed Standards. Research
Triangle Park, North Carolina. EPA 450/3-83-009a. April.
U.S. Environmental Protection Agency (EPA). Office of Air Quality Planning.
1984. Review of New Source Performance Standards for Primary Copper
Smelters. Research Triangle Park, North Carolina. EPA 450/3-83-018a.
March.
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APPENDIX D
TECHNICAL ISSUE PAPER NO. 4
RADIOACTIVITY
ISSUE DEFINITION
Issue Description
In 1978, Congress passed the Uranium Mill Tailings Radiation Control
Act (UMTRCA) (Public Law 95-604). Under Title I, this law directs the
Department of Energy (DOE) to identify inactive uranium mill tailings sites
to be cleaned up to meet EPA standards. Title II of UMTRCA requires active
facilities to be licensed by the Nuclear Regulatory Commission (NRC) and to
meet the EPA standards.
Uranium mill tailings are regulated under UMTRCA and would therefore
not come under a RCRA Subtitle D program for mining wastes. However,
uranium mine wastes (overburden, sub-ore, etc.) are not currently
regulated on a national basis. In addition, some nonradioactive mining
operations, including phosphate, produce mine wastes and tailings that are
radioactive. Uranium mine wastes, as well as radioactive phosphate mine
wastes and tailings are potential candidates for Subtitle D regulation.
Uranium ore is mined by either open pit or underground mining methods;
phosphate is open pit mined. Both mining industries produce waste rock
which is not used in the milling process, in addition to tailings.
Tailings are the by-products of the milling process. In addition, a small
percentage (82) of uranium is extracted using in-situ methods, otherwise
known as solution mining (EPA 1985). This method does not produce waste
rock.
The majority of uranium mining is conducted in New Mexico, Colorado,
Wyoming, and Utah. The majority of phosphate mining is conducted in
Florida, North Carolina, Idaho, and Tennessee, and smaller amounts are
mined in Utah and Montana. Roughly 752 of the phosphate mined in the
United States comes from Florida (EPA 1985).
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Uranium and phosphate mining activities in the United States account
for the majority of mine wastes generated in this country. The estimated
cumulative mine wastes and tailings generated by these two industries from
the years 1910 through 1981 (EPA 1985), in millions of metric tons, are as
follows:
Tailings Mine Vastes Total
Uranium 180 2,000 2,180
Phosphate 2,200 5,500 7,700
The estimated volume of radioactive mine wastes containing more than 5
pCi/g from the phosphate and uranium industries is 443 million metric tons.
The estimated volume containing 20 pCi/g or more is 93 million metric tons
(EPA 1985). The total amount of radioactive mine wastes generated for all
mining industries, including asbestos, copper, gold, silver, lead,
phosphate, uranium, and zinc, containing more than 5 pCi/g is 755.2 million
metric tons. The total for the same industries with wastes exceeding 20
pCi/g, is 405.2 million metric tons (EPA 1985).
Sources, Pathways and Receptors
The primary risk to human health and the environment from uranium and
phosphate mine wastes is from radionuclides. Phosphate rock typically
contains uranium-238 concentrations that range from 20 to 200 mg/Kg, which
is 10 to 100 times higher than background concentrations (EPA 1984a).
Uranium-238 decays and forms radium-226, radon-222, and other
radioactive constituents called radon daughters. Radon is a very mobile,
inert gas that can diffuse through soil and rock and into the atmosphere.
The ingestion and inhalation of radon and its daughters is known to cause
cancer and chromosomal aberrations (EPA 1984b). Radon is of particular
concern when it occurs indoors, where there is little air exchange and the
gas can concentrate.
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Wind erosion can transport both waste rock and tailings. Airborne
radioactive contaminants can be dispersed great distances; however, in
general, windblown contamination is only significant immediately near the
waste piles (UMTSP 1986).
Radioactive contaminants can be transported via surface or ground
water. Erosion can move these contaminants into streams. The radioactive
contaminants can be leached into ground water via precipitation
infiltrating through the waste dumps. Typically, the radionuclides are
relatively immobile in ground water except under acidic conditions.
Oxidizing conditions can also mobilize particular radionuclides (e.g.,
uranium).
One primary area of concern for radioactive mine wastes is their
removal and use as fill materials or aggregate. Structures built on
soil contaminated with radiation have'elevated indoor radon concentrations,
which pose potential health risks to the occupants. The unrestricted use
of these wastes is the most significant health threat from these materials
(UMTSP 1986). The misuse of mining waste material is discussed in more
detail in Technical Issue Paper No. 7, Direct Human Contact and Misuse.
Site Conditions
For a potential adverse affect on human health or the environment to
occur, three site conditions must exist: a source of radionuclides,
pathways to transport the radionuclides, and receptor populations. Because
these conditions vary from site-to-site, evaluation and management controls
must be site specific. Radionuclides present a unique problem because the
radionuclides can exist as three phases: as a gas (radon), in a solid
matrix (waste rock), and dissolved in water. Therefore, the evaluations
must assess pathways of water, air, and direct contact.
As indicated in the previous paragraph, evaluation must be site
specific. For example, uranium mining and milling is primarily conducted
in the remote, arid west. The lack of precipitation generally limits
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surface and ground water contamination, although there are exceptions.
Transport by wind erosion does occur. The remote locations of the majority
of uranium mines and mills precludes the use of waste materials as building
materials, although there are numerous documented cases of the use of
radioactive mine wastes and tailings for building materials where these
wastes were readily available. The use of uranium mill tailings in Grand
Junction, Colorado is one highly publicized example.
Phosphate is primarily mined under wet conditions. Dewatering
practices are typically used to decrease the volume of ground water
entering the mined areas. Ground water and surface water contamination are
possible, although there is little data available to evaluate the
potential. Phosphate mining in the west is under arid conditions, and
therefore the potential for surface and ground water contamination is not
expected to be significant.
Example Sites
There are numerous examples of uranium mill tailings sites with various
problems, including ground water contamination and the use of tailings for
building materials. Since it is difficult to separate uranium mine wastes
from tailings from the available data, the following examples are of
National Priorities List (NPL) sites concerning uranium mill tailings. Of
the 39 mine wastes sites on the NPL as of November 1986, 7 sites concern
uranium mill tailings. These include sites in Colorado, Utah, New Mexico,
and Oregon.
One uranium milling site is located in western Colorado. During its 70
years of operation, over 10 million tons of uranium and vanadium ore were
processed. The operation produced tons of solid waste and millions of
gallons of liquid waste. The wastes contained radioactive materials
(uranium, radium, and thorium), metals (selenium, arsenic, cadmium, zinc),
and inorganic chemicals (ammonia, nitrate, sulfate). Major disposal areas
included:
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Six unlined evaporation ponds containing 560,000 cubic yards of
solids and liquids (adjacent to a river)
Seven settling ponds containing 200,000 cubic yards of solids and
tailings (adjacent to a river)
t Three tailing piles containing 10,000,000 tons of tailings
Mill area and other disposal areas
Several proposed remedial actions will eliminate discharge to the
stream. These actions include:
Removal of 900,000 cubic yards of solid waste currently located near
the river and relocation of these materials to a secure disposal
location
Stabilization and closure of tailings piles
Cleanup of contaminated soils in the mill area and nearby town
Collection and evaporation of leachate in lined ponds
Collection and evaporation of ground water in lined ponds
Revegetation of areas
An example of a problem concerning phosphate wastes was the use of slag
for building materials and for fill (DOE 1984). No phosphate mining sites
are currently on the NPL. Elevated levels of uranium and radon have also
been found at sites where uranium was not the primary ore being produced,
including sites in Colorado and Illinois.
ISSUE IDENTIFICATION AND SOLUTIONS
Characterization and Analysis
Air sampling for radon and radon by-products is conducted using a
variety of techniques. A low-cost, simple system of sampling has been
developed using track-etch cups, permitting long-term, low maintenance data
collection (UMTSP 1986). Exposure to radioactive materials can also be
determined by using TLD (thermoluminescent detectors). Additional methods
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of data collection are available; however, they are more expensive and
require closer monitoring of the data collection equipment. Monitoring
stations are located to record radon emanation from radioactive sources as
veil as to determine background levels. In some instances, these data are
collected using a grid system to adequately assess the degree and extent of
radioactive contamination.
Water quality samples from surface and ground water sources are
generally analyzed for uranium and radium in addition to other
non-radiologic constituents. Various types of water analyses (i.e., total,
dissolved, etc.) are discussed in Technical Issue Paper No. 2, Mobile Toxic
Constituents/Water. For surface water samples, representative upstream and
downstream samples are taken. Ground water investigations include
determining the depth to ground water, the direction of flow, the
background water quality, the hydrologic conductivity, and areal extent of
the aquifer. Additional water quality data are collected to determine the
extent of ground water contamination from the mine wastes.
Solid samples are analyzed in a variety of methods. The various
digestion methods used to dissolve the samples are discussed in Technical
Issue Paper No. 2, Mobile Toxic Constituents/Water. Specific radionuclide
concentrations can be analyzed directly by measuring gamma, alpha, or beta
emissions associated with the radioactive decay process. Specific
radionuclides of concern are usually Ra-226, Pb-210, Po-210, U-238, and
Th-230. Various field meters can also be used to detect and measure
overall radioactivity. These instruments do not measure individual
radionuclide concentrations.
The severity of contamination to the environment by radioactive mine
wastes depends primarily on the quantity of material. The greater the
volume of material, the greater the volume of radon gas that can be
produced. Unrestricted access to radioactive mining wastes increases the
chances that material will be removed for use as fill or aggregate. Some
uranium waste sites are remote and/or small in volume and pose little
danger to the environment. The extent of the problem is site specific.
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Phosphate mining occurs generally near less remote populated areas.
The chances of misuse by man are much greater for these areas than the more
remote western locations. Phosphate mining produces the most tonnage of
wastes in the mining sector (EPA 1985). Radioactivity in phosphate mining
waste varies from site to site and is dependent on the original ore body.
Prediction Methods
Numerous factors are involved in transport of radioactive constituents
from mine wastes into the environment. The amount of precipitation,
proximity to both surface and ground water, volume of material produced,
the amount of radioactivity generated from the wastes, and the proximity to
population are all important factors. These factors help predict problem
areas and indicate which problems should be addressed on a site-specific
basis.
Generic models have -been developed to evaluate the problem of uranium
mill tailings. These tend to be overly conservative and not representative
of the various mine and mill site conditions. Other specific models exist
to evaluate various management controls. For example, the amount of radon
gas diffusing through various types and depths of soil/clay covers on waste
and tailings piles can be modeled.
Hydrological models also can evaluate the mass transport of
radionuclides in ground water. These models usually account for the
retardation of the radionuclides by the aquifer material (i.e.,
co-precipitation and adsorption) by incorporating a distribution
coefficient in the model. The distribution coefficient should be measured
by use of batch tests on site-specific soils. Column experiments may be
required for the more mobile constituents. The models also require site-
specific hydrologic information, including aquifer properties, thickness,
etc. Geochemical models based on equilibrium thermodynamics can also be
used to predict equilibrium concentration in waters and the results of
precipitation, adsorption, and dissolution.
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Management Controls
Various management controls are available to eliminate sources or
interrupt pathways to receptors. Containment is a control measure
typically used at radioactive waste sites. The waste piles which pose
significant risks can be covered with an earthen cover to prevent
infiltration of precipitation, dispersion by wind and water, and radon
emanation. In addition, in areas where contamination of the ground water
is of concern, liners with leachate collection systems may be required.
In some cases, institutional controls can be used to limit access to
the site and control ultimate land use in the vicinity of the waste. Such
controls can also be used to limit the misuse of waste materials. All of
these techniques limit receptor exposure.
In some cases, actual removal and reburial of wastes in a more secure
area may be necessary. Extraction and treatment of leachate and ground
water to remove the radionuclides may also be necessary.
Verification and Monitoring
Air monitoring can be conducted to measure the radioactivity generated
from the wastes and determine site specific background concentrations. The
number of air monitoring stations could vary depending on the remoteness of
the site.
Surface water sampling locations may be established to determine both
background and onsite concentrations of radioactive constituents. At least
one upstream and one downstream sampling location station should be
established to assess potential stream impacts.
Ground water sampling sites may be established to determine ground
water flow directions, extent of the aquifer, permeability and conductivity
of the aquifer, as well as background and onsite radioactive constituents.
The number of sample locations will vary depending on depth to ground
water, use of aquifer, and remoteness of the location.
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The extent to which monitoring should be conducted as veil as the
frequency of sampling and the number of data stations should be determined
on a site-specific basis. In addition, some form of land use controls and
verification may be required to prevent the misuse of the waste material by
humans. A system of low level maintenance may also be implemented to
ensure that covered piles continue to meet the necessary standards. This
could include aerial photography as well as periodic site investigations.
ADEQUACY OF EXISTING INFORMATION AND RECOMMENDED REGULATORY SUPPORT
ACTIVITIES
Adequacy of Existing Information
Currently, large amounts of information exist concerning environmental
impacts of uranium wastes. Because most of the data collected are on
tailings, more information is needed on other waste materials such as
low-level ores and waste rock. In addition, the data need to be integrated
into an overall risk-based approach so that sources, pathway, and exposure
to receptors can be evaluated in a formal manner.
Data are needed on the potential for surface and ground water
contamination from phosphate mining. Information on the risk to the
population and the environment from phosphate mining are also needed to
adequately address the magnitude of the problem. Data on the volumes and
risks associated with radioactive wastes from other mining industries are
also needed.
Recommended Regulatory Support Activities
Based on a preliminary review of the available data concerning
radioactive wastes, additional information is needed in several areas.
These areas include:
Integrated data bases should be compiled to assess sources,
pathways, and receptors.
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Formalized risk assessment methodology should be developed.
Data concerning impacts on human health and the environment from
phosphate mining wastes should be collected or compiled.
Computer models that can be tailored to site specific conditions
should be developed. These models need to incorporate various
aspects such as volume of wastes, proximity to surface and ground
water, and proximity to populations and sensitive environments.
Specific models may have to be developed for remote arid, western
conditions and populated humid, eastern conditions.
SUMMARY AND RECOMMENDATIONS
The uranium and phosphate mining industries produce the largest volume
of waste material of any of the mining industries. These wastes are
characterized by large volumes and low radioactivity. Uranium mill
tailings are currently regulated under UMTRCA. The radioactive uranium
mine wastes, as well as radioactive mine wastes generated from other mining
sectors are not currently regulated.
The primary risk to human health and the environment from uranium and
phosphate mine waste is from radionuclides. The source radionuclides can
exist as a gas (radon), in solid matrices (waste rock), and as dissolved
species in water. Because of these various states, all pathways of
transport must be considered. In particular, air pathways, surface and
ground water, and direct contact pathways are important. Accumulations of
radon gas in buildings as a result of misuse of radioactive waste as
construction material is one of the most significant health threats from
radioactive waste materials.
The problem of radioactive mine waste should be dealt with by
considering the site-specific sources, pathways, and receptors. That is,
the type of environment the various sites are located in and the degree of
risk to the environment should be considered. Management controls that
eliminate the transport by various pathways include capping and other
containment techniques. These controls have been successful in mitigating
radon migration, wind dispersal and infiltration of precipitation.
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Controls of radioactive mine wastes need to take into account site-
specific characteristics. Remote sites with little potential for ground
water contamination should not be subject to the stringent controls that
are required at sites which are located near population centers and/or
potable aquifers. In some instances, local and state regulations may be
sufficient to deal with some problems, such as use of radioactive mine
wastes for building and fill purposes. Institutional controls such as land
use restrictions should also be evaluated. In all cases, monitoring at the
sites should be performed. The exact nature of the monitoring program
should be based on site conditions and management controls used at the
site.
Although a large quantity of data exists concerning radioactive waste
from mining operations, most of the information concerns uranium tailings
piles. Additional data on the quantities of uranium mine wastes not
regulated under UMTRCA need to be compiled.
The following activities are recommended to support further technical
understanding of the environmental impacts of radioactivity associated with
mining wastes:
Develop a formalized risk assessment methodology.
Develop better models to predict radionuclides transport in air,
soil, and water.
Integrate existing data for performance of a risk-based evaluation.
Collect additional data on the phosphate industry, particularly on
the potential for ground water and surface water contamination.
Evaluate data on risks associated with radioactive wastes from
nonradioactive mining sectors.
REFERENCES
U.S. Department of Energy (DOE). 1984. Evaluation of Relative Hazards of
Phosphate.Products and Wastes. D0E/LLW-24T. National Low-Level
Radioactive Waste Management Program, Idaho Falls, Idaho.
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U.S. Environmental Protection Agency (EPA). 1985. Report to Congress,
Wastes from the Extraction and Beneficiation of Metallic Ores, Phosphate
Rock, Asbestos, Overburden from Uranium Mining and Oil Shale.
EPA/530-SW-85-033. Office of Solid Waste and Emergency Response,
Washington, D.C.
U.S. Environmental Protection Agency (EPA). 1984a. Radionuclides,
Background Information Document for Final Rules, Volume I. EPA
560/12-80-003. Office of Radiation Protection, Washington, D.C.
U.S. Environmental Protection Agency (EPA). 1984b. Radionuclides,
Background Information Document for Final Rules, Volume II. EPA
520/1-84-002-2. Office of Radiation Protection, Washington, D.C.
Uranium Mill Tailings Study Panel (UMTSP). 1986. Scientific Basis for Risk
Management of Uranium Mill Tailings. National Academy Press, Washington,
D.C.
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APPENDIX E
TECHNICAL ISSUE PAPER NO. 5
ASBESTOS
ISSUE DEFINITION
Issue Description
Asbestos is a general term applied to a number of fibrous minerals that
are used widely in many different applications. Because of their unique
combination of resistance to heat and chemical attack, high tensile
strength, and flexibility, asbestos fibers are found in thousands of
commercial products. Three mines are currently producing asbestos in the
United States to supply a portion of the manufacturing need. In addition,
several mines and mills are not operating or abandoned.
The existing permissible exposure limit set by the Occupational Safety
and Health Administration (OSHA) in the workplace is based on an analytical
methodology that only can detect asbestos fibers with an aspect ratio
greater than 3:1. This includes fibers with a diameter larger than 0.25
microns, or about 5 microns in length. In reality, for every large fiber
present, thousands of "small" asbestos fibers, or those less than 5 microns
in length, may also be present. The issue is whether these small fibers
are as important as the large fibers in creating risk to workers. This
becomes especially important at mines or mills where ores other than
asbestos are processed, but which contain asbestos minerals as gangue or
waste. In these situations, the lack of long fibers meeting the regulatory
criteria may cause the asbestos problem to be dismissed when, in fact, the
shorter fibers may pose a health risk.
It is well known that exposure to asbestos can cause cancer of the lung
and internal organs, primarily through inhalation. The relationship
between asbestos and cancer was not established until 1949, when a report
was published describing the excess cancers of the lung of asbestos workers
in Quebec (NIH 1981). Since that time, many studies of occupational
exposures to asbestos point to an overwhelming relationship between
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asbestos and cancer. Lung cancer is the most commonly observed type of
cancer, caused when fibers are inhaled and become lodged in the alveoli of
the lung. The risk of lung cancer appears to be directly proportional to
cumulative exposure. Mesothelioma is a rare and always fatal cancerous
tumor, difficult to diagnose, affecting the lining of the chest or the
abdomen. Case studies from South African crocidolite mine workers show
overwhelmingly the association of asbestos and mesothelioma (NIH 1981).
Suggestive evidence indicates that when asbestos is ingested, it may also
cause cancers of the larynx, digestive system, and kidney.
No conclusions can be drawn about the relative cancer risk from
different types of asbestos, although some information shows that
chrysotile may not be as hazardous as other types of asbestos. Of the
asbestos fibers found at autopsy in human lungs, a majority are less than 5
microns in length. Smaller fibers remain suspended in the airways for
longer periods, and it may also be possible that some fibers become
fragmented as a result of biological activity in the lung tissue. Because
available studies often lack information on potential confounding factors
such as cumulative exposure, smoking history, and physical characteristics
of the fibers, it is extremely difficult to determine the relative danger
posed by different types or sizes of fibers. However, there does not
appear to be a fiber length below which fibers have no carcinogenic
potential.
The combined effect of smoking and asbestos exposure may be greater
than the simple sum of their separate effects, which means that asbestos
workers who smoke increase their cancer risk (EPA 1985a). It takes at
least 15 years after initial exposure for asbestos-related cancers to
appear. This latency period for mesothelioma is longer, about 30 to 40
years. A non-cancerous disease caused by asbestos is asbestosis, a
respiratory disease that scars the tissues of the lung. Advanced
asbestosis may even produce cardiac failure.
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Sources, Pathways and Receptors
The term asbestos generally includes the fibrous variety of the mineral
serpentine, known as chrysotile, and the fibrous members of the amphibole
mineral series, including crocidolite, amosite, anthophyllite, tremolite,
and actinolite. Serpentine (chrysotile) is by far the most common and
widespread asbestos mineral. Serpentine occurs in 23 states, including but
not limited to Arizona, California, Connecticut, Georgia, Idaho, Maryland,
New Jersey, New York, North Carolina, Oregon, Vermont, and Virginia.
Serpentine is so abundant in California that it is the official state rock.
Commercial deposits of serpentine and amphibole-bearing rocks in North
America are found primarily in California, Vermont, North Carolina,
southern Arizona, and Quebec, Canada (Lefond 1975).
There are currently three asbestos mines operating in the U.S., at
Copperopolis and Santa Rita, California, and Hyde Park, Vermont (Virta
1987). Mines that closed in the 1970's or early 1980's include three mines
near Globe, Arizona; Atlas Asbestos near Santa Cruz, California; Coalinga,
California; and Powhatan Mining in Burnsville, North Carolina (NIH 1981).
Mills for processing of the asbestos ore are or were located near the
mines; the mill for the North Carolina mine was located in Baltimore,
Maryland. U.S. production figures for 1983 indicate about 70,000 tons of
asbestos were produced (U.S. Bureau of Mines 1985). The mining and milling
of ores such as talc, with associated asbestos minerals, also produce
asbestos waste material.
The principal pathways for asbestos to reach receptors are air and
surface water. The use of open pit mining methods, air separation milling
methods, and transportation of asbestos products and wastes by truck has
resulted in elevated asbestos concentrations in the vicinity of mining,
milling, and manufacturing areas. The configuration of asbestos fibers
long, thin, often spirally shaped particles allows them to remain
suspended for long periods in the atmosphere. Studies of atmospheric
pollution in the area surrounding asbestos mines and mills in Finland
showed small amounts of asbestos dust as far away as 27 kilometers (NIH
1981, p. 52). Asbestos in surface waters, particularly drinking water
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supplies, is also widespread due to erosion of natural sources, water
transport of mine and mill tailings, or disposal of asbestos wastes near
water. Asbestos can also travel long distances in water, as shown by
studies in Lake Superior (NIH 1981, p. 54). Although asbestos has been
shown to occur in ground water in areas of serpentine-bearing rock,
typically ground water is not an important pathway. Direct dermal contact
is also not considered a significant exposure pathway.
The receptors considered in asbestos research to date have been workers
exposed to asbestos on the job or the public exposed to asbestos in the
environment. Existing regulations specify limits on human exposure to
asbestos.
Site Conditions
As discussed above, there are only three active mine and mill sites
which extract and process asbestos in the U.S. Additional mines and mills
are currently not operating or abandoned. The quantity of waste material
associated with these sites is typically very large, since the processing
involves breaking down the ore to extract the fibers. Approximately 70
million metric tons of mine and tailings waste have been generated by
asbestos mining activities from 1910 through 1981 (EPA 1985b).
The problem may extend to other types of mining where asbestos minerals
are present as accessories. For example, the widespread occurrence of
serpentine encompasses the hot-springs-type gold mines located in
California, and talc mines and mills in New York State. Excess lung
cancers have been noted in workers at several New York talc mines (NIH
1981, p. 27). The talc is suspected of containing tremolite and smaller
amounts of anthophyllite and chrysotile. In Italy, where talc does not
occur with asbestos materials, excess lung cancers or mesothelioma have not
been reported in that worker population (NIH 1981, p. 27).
Three conditions must exist at a site for a potential adverse human
health or environmental effect to occur: a source of asbestos, a pathway
for transport, and a receptor population. Because these conditions vary
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from site to site, the evaluation of the problem must be site specific. If
any of these three conditions are eliminated, the potential problems may
not occur. Therefore, management controls should emphasize alleviation of
these conditions and must also be site specific.
Example Sites
Several asbestos contaminated sites are currently on the Superfund
National Priorities List (NPL). These include Globe, Arizona; South Bay
Asbestos, Alviso, California; and Coalinga, California. The Globe, Arizona
site has been remediated by relocating residents and capping contaminated
materials. The South Bay site contains a combination of wastes from an
asbestos pipe manufacturing facility and natural serpentine rocks used to
build levees. Temporary remedial actions have included placement of a
surface binder on the exposed levees to reduce blowing dust. The extent
and impact of the contamination is being evaluated. At the Coalinga site,
extensive natural outcroppings of serpentine rock upwind and upgradient of
the town of Coalinga have been mined for asbestos. The study under way is
evaluating the impact of asbestos to the air and surface waters from the
abandoned Atlas and Coalinga mine and mill areas.
ISSUE IDENTIFICATION AND SOLUTIONS
Characterization and Analysis
Since inhalation is the primary asbestos pathway, asbestos
concentrations at mine and mill sites are determined by air monitoring.
Typically, a personal air monitoring pump is utilized to draw air in the
breathing zone through a mixed cellulose ester filter. The filter is
treated and mounted on glass slides for analysis under a positive phase
contrast optical microscope (PCM analysis) using the NIOSH recommended
method 7400. The method cannot detect fibers smaller than about 0.25
microns in diameter and about 5 microns in length, and cannot determine
fiber composition (chrysotile versus amphibole versus cellulose). The
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resulting data are a measurement of long, microscopically visible fibers
which can be compared to the OSHA workplace guidelines of 0.2 fibers per
cubic centimeter (cc) of air (Federal Register, June 20, 1986).
The scientific community is not in agreement that long fibers present
the only health hazard. Short fibers, or those with diameters less than
0.25 and lengths less than 5 micron, also present a health risk. At this
time, there does not appear to be a length below which fibers have no
carcinogenic potential. At mill sites in particular, short fibers are more
abundant since the processing tends to remove the more economically
desirable long fibers.
To detect the smaller fibers, electron microscopy methods are required.
High-volume air samplers are also preferred to draw the necessary volume of
air through the filter as required by the method. In this case the filter
is dissolved, coated with a thin film of carbon, then examined at 20,000
times magnification using a transmission electron microscope. The analyst
counts and describes every fiber observed in a set number of fields of
view. Each fiber is identified as to mineralogical type. This type of
analysis costs approximately $500 to $800 per sample, compared to about $40
for the positive phase contrast (PCM) NI0SH method described above.
However, if performed properly, the transmission electron microscopy (TEM)
method is the more accurate way to determine fiber lengths and composition
of asbestos.
Prediction Methodology
At sites where asbestos may be a concern, monitoring for occupational
exposure should occur according to procedures recommended by OSHA.
However, to better characterize actual asbestos concentrations, paired
samples should be analyzed both by optical (PCM) and electron microscopy
methods (TEM), at least initially. In this way, a correlation may be
established between actual short fiber counts and optically visible or
NI0SH fibers. Then, monitoring could continue with the less expensive PCM
method, with the assurance that short fiber concentrations are being
accurately estimated.
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The Bureau of Mines has conducted research to determine the ratio of
fibers detected vith scanning transmission election microscopy (STEM) to
those detected with PCM (Snyder et al. 1987). Some samples containing
chrysotile had STEM/PCM ratios of up to 53:1. They determined that PCM
alone does not detect all regulatory particles (3:1 aspect ratio) and that
roughly one-third of such particles are below the resolution of the optical
microscope. A multiplication factor of 1.5 was developed for chrysotile
samples from mining sites.
At sites where no long NIOSH fibers are detected, making the
correlation described above impossible, another alternative may be
feasible. Rather than having to rely solely on the expensive TEM analysis,
samples of asbestos in air could be paired with samples of total suspended
particulates (TSP). In this way, a correlation could be established
between asbestos fiber counts and dust concentrations, assuming that the
suspension of asbestos in air occurs along with suspension of dust in the
air. Then, monitoring could continue using the inexpensive TSP
measurements (about $10 per sample), knowing the relationship between TSP
and asbestos for given wind conditions. Applications of this type have
been used with some success while measuring asbestos emissions from unpaved
roads (EPA 1981).
Non-asbestos mine sites where asbestos contamination is suspected
should also undergo careful evaluation. Samples of the waste rock and
tailings should be analyzed using TEM to determine the amount of asbestos
that could potentially be liberated. However, depending on the mine and
mill processes used, the actual emissions to the air could vary greatly.
Open pit mining, crushing procedures, or wet versus dry milling will all
affect the amount of asbestos in the air. Air sampling could be performed
selectively on a site-by-site basis to determine the need for environmental
protection measures and ongoing monitoring. Samples should be collected
and analyzed using TEM at sites where process water is discharged could
potentially impacting drinking water supplies.
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Management Controls
At a minimum, management controls for asbestos mine and mill sites
should continue to follow existing OSHA and EPA requirements. OSHA
regulations for asbestos, updated in June 1986 (Federal Register, June 20,
1986), require daily onsite air monitoring of regulated areas, employee
education and training, and medical surveillance. EPA requires that all
asbestos-containing wastes from mills be disposed of without any visible
emissions to outside air or that wetting practices must be used to control
emissions.
Management controls may also extend to asbestos mine and mill waste
water. Increased concern over asbestos fibers in the air has resulted in
conversion of some dry processes to wet processes, including use of water
sprays to control dust from tailings or gob piles. However, this practice
increases the potential for contamination of drinking water supplies.
Controls on wastewater prior to discharge may include pretreatment, primary
and secondary treatment, and some sort of microfiltering such as
diatomaceous earth filtration as a tertiary step to remove asbestos fibers.
Perhaps the most important control should be proper handling and
disposal of asbestos waste piles. Techniques such as waste reduction and
separation should be practiced to the extent possible. The most effective
way to control asbestos emissions from waste is to deposit it in a site
that is covered with a layer of non-asbestos-containing waste or earth at
least 8 inches deep and stabilized with a vegetative cover. An alternative
method is to maintain a resinous or petroleum-based dust suppression cover;
however, covers of this type typically do not have a long life.
Maintenance and upkeep would be essential to prevent breakdown or erosion
of the cap and release of asbestos.
At abandoned or inactive sites, waste piles are the major concern. At
these sites, the most effective management control is elimination of the
pathway. In most instances, capping of the waste will mitigate release to
the air.
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Management practices may be necessary at mines and mills that process
ores that contain asbestos minerals in the gangue or host rock. The type
of management control depends upon the operations at the site and the
specific site conditions. For example, crushing operations may require
controls such as vet processing to mitigate dust release.
Verification and Monitoring
In all cases, the site conditions and management controls dictate the
necessary verification and monitoring. Some of these monitoring
requirements were discussed in the previous section. For example, if waste
piles are capped, periodic monitoring and maintenance of the integrity of
the cover would be required. In addition, a monitoring well might be
required at sites containing asbestos to evaluate the problem and verify
the integrity of management controls.
ADEQUACY OF EXISTING INFORMATION AND RECOMMENDED REGULATORY SUPPORT
ACTIVITIES
Adequacy of Existing Information
Information is not currently available to determine the relative
adverse effects from different types or sizes of asbestos fibers. In
addition, only limited data exist on the actual composition and size
distribution of asbestos minerals at sites. This information is almost
totally absent at sites where asbestos is not the main mineral processed
but may be contained in the gangue or host rock. More data are needed on
correlating TEM analyses with PCM or TSP analyses. This correlation is
necessary to reduce analytical costs and accurately assess effects of PCM
observable fibers.
Recommended Regulatory Support Activities
Based on a preliminary review of the available data, additional data
needs were identified in the previous paragraph. These data needs could be
filled by the following activities:
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Determination of the relative adverse effects of various asbestos
minerals and fiber sizes
Collection of data (both TEM and PCM) from mining sites with
asbestos minerals in the gangue or host rock
Evaluation of various analytical methods to establish correlations
Formalization of a risk based approach to assess potential human
health and environmental effects; particularly important to
evaluation of impacts from waste piles (i.e., potential of soil
particles to become airborne)
SUMMARY AND RECOMMENDATIONS
There are relatively few asbestos mines and mills active in the United
States. However, because of the widespread distribution of asbestos
minerals, primarily serpentine, many non-asbestos mine and mill operations
present a risk of asbestos exposure during processing. The role of
asbestos as a cancer-causing substance through inhalation and ingestion is
well-known. The exact mechanism by which asbestos causes disease fiber
shape, length, composition and at what level of exposure, is not
well-understood.
Current regulations for asbestos are based on the assumption the "long"
fibers, greater than 5 microns in length with an aspect ratio greater than
3:1, present the greatest risk. The optical microscopy analytical method,
NIOSH 7400, on which the regulations are based, cannot detect fibers
smaller than 0.25 microns in diameter. However, thousands of "small"
fibers, detectable only using transmission electron microscopy techniques,
may be present in the sample. This may be particularly true at mill sites
where the longer fibers have been processed, leaving short fibers as waste
material. These small fibers may pose as great a threat to health as the
long fibers upon which risk has traditionally been based.
For asbestos to potentially affect human health and the environment,
three conditions must be present: a source, a pathway, and a receptor
population. Elimination of any of these three categories at a site may
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reduce or alleviate adverse effects. Because the three conditions vary
from site to site, the evaluation of the potential impacts and selection of
management controls must be site specific. Because the air pathway is the
primary concern at many sites, capping or containment of the waste piles
can be an appropriate control. During operations such as crushing and
blasting, wet processing and/or dust control may be necessary. At all
sites with potential human and environmental effects, air monitoring should
be performed to assist in evaluating the problem and verifying management
controls.
Based on a preliminary review of existing information, several
activities are recommended. These include the following:
Determination of the adverse effects of various asbestos minerals
and fiber sizes (especially small fibers)
Evaluation of various analytical methods
Collection of data at selected sites using both optical and
transmission electron microscopy techniques
Formalization of a risk based approach to assess potential human
health and environmental effects
REFERENCES
Federal Register. June 20, 1986. Vol. 51, No. 119. Rules and Regulations,
Part 1910, Subpart B of Title 29 of the Code of Federal Regulations.
Lefond, S.J. ed. 1975. Industrial Minerals and Rocks. American Institute of
Mining, Metallurgy, and Petroleum Engineers. New Jersey.
National Institute of Health (NIH). 1981. Asbestos: An Information Resource
(Richard J. Levine, M.D., ed.) NIH Publication No. 81-1681.
Snyder, J.G., Virta, R.L.; and Segreti, J.M. 1987. Evaluation of the Phase
Contrast Microscopy Method for the Detection of Fibrous and other
Elongated Mineral Particulates by Comparison with a STEM Technique.
American Industrial Hygiene Association Journal, May.
U.S. Bureau of Mines. 1985. Mineral Facts and Problems. Washington, D.C.
U.S. Government Printing Office.
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U.S. Environmental Protection Agency (EPA) Office of Air Quality. 1981.
Assessment and Control of Chrysotile Asbestos Emissions from Unpaved
Roads. EPA 450/3-81-006.
U.S. Environmental Protection Agency (EPA) Office of Solid Waste. 1985a.
Asbestos Waste Management Guidance. EPA/530-SW-85-007.
U.S. Environmental Protection Agency (EPA) Office of Solid Waste. 1985b.
Report to Congress: Wastes from the Extraction and Beneficiation of
Metallic Ores, Phosphate Rock, Asbestos, Overburden from Uranium Mining
and Oil Shale. EPA/530-SW-85-033
Virta, R. (U.S. Bureau of Mines). 1987. Personal communication with W.
Sydow of CDM Federal Programs Corportion. June 8.
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APPENDIX F
TECHNICAL ISSUE PAPER NO. 6
CYANIDE
ISSUE DEFINITION
Issue Description
The extraction of gold and silver account for the majority of the
cyanide used in today's mining industry. In the United States, 80% of the
gold and 5£ of the silver are processed using cyanidation practices. In
principle, cyanidation is the formation of a stable complex between cyanide
ions and gold, silver and other metals. In contrast to stronger process
solutions, cyanide solutions demonstrate a selective preference for
dissolution of gold and silver in ore.
During the last decade, -cyanide heap leaching has developed into an
efficient alternative to other methods for the extraction of gold and
silver from oxidized or refractory ore. Low capital and operating costs
coupled with the design flexibility to accommodate many site conditions
make heap leaching a logical choice for the processing of lower grade ore
bodies, once considered economically marginal if processed by conventional
flotation methods (Hiskey 1985, Potter 1981).
Numerous cyanide compounds and their derivatives can be found in the
process solutions, waste effluents and tailings generated by the heap
leaching process. In general, they can be classified as free cyanides,
simple cyanides and complex cyanides. The relative stability of cyanide
complexes in these solutions ranges from weak to strong. As cyanide
complexes become more stable they are less likely to liberate "free"
cyanide in waste solution. Molecular hydrogen cyanide and free cyanide are
thought to be most toxic to aquatic life. Significant cyanide degradation
processes occur in nature, including volatilization, biodegradation, and
adsorption.
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Solution discharge is the most common mechanism facilitating the
migration of contaminants offsite. Uncontrolled discharges may occur for
the following reasons:
Poor facility siting; e.g., locating within an active floodplain or
in the mouth of a constricted drainage
Inadequate pond capacity to handle precipitation events or runoff
from the active mill site
Poor offsite surface water management; diversion systems around the
perimeter of the facility fail to exclude offsite runoff from
entering the process circuit
Seepage from ponds occurring as a result of a faulty (torn or poorly
sealed) liner
Occurrence of an extreme precipitation event that exceeds the design
capacity of the ponds
Poor heap construction resulting in instability and eventual heap
displacement with the potential to break solution lines and cause
liner failure
Placement of tailings and other wastes in a location where effluent
generated by the leaching action of precipitation is uncontained
Sources, Pathways and Receptors
For potential adverse impact to human health or the environment to
occur, three specific site conditions must exist:
A source of cyanide (the form of cyanide should be toxic or
potentially toxic)
A pathway to transport the cyanide
A receptor population
Because the cyanide can exist in various forms, sources and pathways
must be evaluated in detail. For example, as the pH of a cyanide solution
is lowered, the cyanide is released from solution as hydrogen cyanide gas.
Under these conditions, the major pathway of concern is air and the major
receptor is human and wildlife populations. In most instances, the
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discharges are maintained at high pH levels and the major pathways of
concern are surface and ground water. If surface water is contaminated,
the main receptors of concern are aquatic organisms. In some circumstances
complex cyanides will not affect the aquatic life (Ingles 1981). If ground
water is contaminated, the main receptor of concern is humans, which may
use the water as a drinking water supply. Contaminated ground water may
also recharge surface water bodies and affect aquatic organisms, wildlife,
or livestock.
Site Conditions
The impact of solution discharge or waste placement must be evaluated
in the context of its environmental setting. An uncontrolled discharge at
an arid site will have a different impact than one occurring directly
upgradient of a town's potable water supply. Important factors in
determining whether waste placement or uncontrolled solution discharges
present a problem include:
Physical location of waste or discharge; i.e., proximity to surface
water, ground water, human habitation
Volume of contaminated material or effluent and concentration of
cyanide and metallo-cyanide complexes; persistence of the complexes
in the environment
Potential for wastes to be remobilized; e.g., by rain
Determination of whether degradation has occurred, its extent and
the potential for it to continue
Mitigating measures
Potential for recurrence
Heap leach operations, like the ore they process, are unique in that
they should be evaluated on a site-specific basis.
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Example Sites
Only one of the Super£und National Priorities List (NPL) sites has an
identified problem related to cyanide. Most operating facilities move
quickly to eliminate cyanide migration from tailings piles and
impoundments. In South Dakota, an operating gold mine discharged cyanide
to the adjacent river in concentrations lethal to aquatic life. This
discharge is nov treated before release. In California, the tailings
impoundment at a gold mine leaked, resulting in ground water and surface
water contamination. The contamination is currently being contained and
treated before discharge.
ISSUE IDENTIFICATION AND SOLUTIONS
Characterization and Analysis
The analytical methods used to determine the cyanide concentrations are
extremely important. Ideally, sample analytical methods should yield
reproducible data which accurately describe concentrations of the cyanide
species to be determined. The following are the most widely used
analytical methods for measuring cyanide concentrations:
Total cyanide: measures total CN in the sample and is subject to
interference by thiocyanates. Some cobalt, gold, and platinum
cyanide complexes may not be completely measured.
Chlorine Amenable Cyanide: represents the difference betveen total
CN and CN neutralized by chlorine. This value is only as good as
the value for the total CN analysis. The value does not include the
cyanide complexed with iron.
Weak Acid Dissociable Cyanide: measures the free CN ion and most
simple CN complexes.
Free Cyanide: measures free CN but is subject to interference by
thiocyanates, sulfates, oxidizing agents, nitrates, urea and other
organic compounds.
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The use and reliability of these methods are complicated by the
following: extreme care and skill are needed to produce consistent
results, different cyanide complexes require different methodologies,
sample preparation and preservation are specific for each complex and
methodology, and preservation techniques for samples containing
particulates are not defined (Huiatt 1984). The analytical methods cited
above do not result in concentrations of individual cyanide species. To
understand and evaluate all cyanide species, ion chromatographic techniques
are recommended. Such analytical procedures will result in concentration
of individual cyanide complexes including thiocyanate.
The methods discussed above are used to analyze vater samples.
Reliable techniques and procedures do not ekist for solid matrices and
should be developed.
Once the solutions are characterized, the fate and transport of the
cyanide in the environment should be evaluated. Because cyanide undergoes
a vide variety of reactions in the environment, the system and its
assessment can be extremely complex. Reactions include photolysis,
hydrolysis, volatilization, biodegradation, and adsorption. Some of these
processes can be modeled using thermodynamic models and others can be
measured using column leach tests.
Prediction Methodology
No accurate methods exist to predict the fate and impact of cyanide in
the environment. The best current approach is to characterize the leachate
from the heaps just before closure. Conclusions can then be made
concerning the toxicity of various metal cyanide complexes, the mobility of
the complexes, and potential environmental reactions. Column experiments
may also yield useful information. In addition, the solid materials (the
spent ores) in the heap should be characterized with respect to
mineralogical and elemental composition and be evaluated in relation to
leachate quality. Based on this comparison, predictions can be made
concerning potential leachates from various types of ores.
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In addition to understanding the chemistry and fate of leachates,
problem areas can potentially be identified before operation commences by
evaluating the environmental setting and proposed operations. For example,
siting and design criteria can be used to alleviate potential run-on and
run-off problems.
Management Controls
Problems occurring at heap leach facilities can be characterized
according to their source of origin. Problem frequency is directly related
to factors influencing each source. For instance:
Facilities Siting Problems: A poor location, such as at the mouth
of a constricted drainage, can result in seasonal flooding problems
as water enters the leach site and exceeds the capacity of the
ponds, causing uncontrolled discharge.
Design Construction Problems: Pond capacities can be exceeded by:
- Underestimating climatic factors, such as precipitation or
overestimating evaporative losses;
- Inadequate surface water diversions fail to keep offsite overland
flow from entering the leach circuit. Ignoring these factors
could lead to a discharge at least once a year during annual high
precipitation periods;
- Using inappropriate liners under a given set of environmental
circumstances (e.g., PVC which is subject to UV degradation); and
- Poor quality control during liner installation can lead to seepage
of process water into the ground water on a continual basis.
Operational Management Problems: Freeboard levels in ponds should
be continually monitored to assure adequate storage for annual
precipitation events. Facilities in arid locations may use
emergency ponds for back up water if water is hard to obtain
throughout the year. Process pond levels in net precipitation areas
may need to be reduced prior to winter shutdown. This will
facilitate storage of snow that may accumulate over the winters in
addition to any spring rains that might occur. Failure to maintain
adequate storage may result in a discharge.
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Operational management can be utilized to help reduce cyanide
concentrations in controlled discharges of waste and effluent. In so
doing, adverse environmental impacts can be mitigated and treatment costs
optimized. Methods that might reduce the amount of cyanide to be treated
include:
Reduction of waste volume
Maintenance of tight controls on process conditions that might
otherwise require the addition of more cyanide
Management of other process solution constituents that consume
reagents that eliminate cyanide
The volume of waste solutions can also be reduced by segregating waste
streams and rerouting process solutions within the mill.
Anticipated waste streams of the leaching cycle should be evaluated
during' the design phase prior to their actual creation in the mill.
Specific cyanide species and the total chemical matrix to be treated must
be.identified and an acceptable treatment process designed. A variety of
methods are in use for destroying cyanide in process water (e.g., alkaline
chlorination, ozonation, peroxidation). The limitations of some of these
methods are not well defined. Each waste treatment process presents unique
environmental concerns and should be fully evaluated before implementation.
Various waste handling alternatives can be used as management controls
to mitigate environmental impacts. For example, reuse of pads for leach
materials will promote volatilization and oxidation of cyanide.
Final reclamation of a heap leach operation is important to prevent
adverse environmental impacts. At closure, the residual process water must
be treated before disposal in order to eliminate the cyanide. In arid
environments, where evaporation rates exceed precipitation, the residual
solutions can be impounded and evaporated. In wet climates, these
solutions must be treated and disposed. Treatment methods should reduce
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constituents of concern to acceptable levels and yet remain compatible with
the environment. Disposal of the treated solutions may include spray
irrigation or discharge into infiltration-percolation beds.
Several options for neutralization of the leached ore heaps include:
t Recirculation of fresh water over the heap in a fresh water rinse
Spray irrigation of the heap with hypochlorite or peroxide
solutions (can get expensive depending on thiocyanate concentration
of the heap)
Natural degradation of cyanide within the heap over time (provisions
must be made to contain any effluent that might drain from the heap)
None of these options has been established as the most effective.
Other important issues concerning heap neutralization include:
neutralization of sections of a heap that have been sealed off by fines and
in which the solution is channeled through the ore and the length of time
necessary for the cyanide concentrations to naturally degrade (Schiller
1983).
Reclamation of a site requires care in handling and disposal of
contaminated material other than ore or process water. Liners can be used
to isolate contaminated sludge in the bottom of ponds from infiltrating
precipitation, and the sludge can be immobilized by adding fixation agents.
The fixed material could thenNbe placed on a liner and buried. Liners
under the heaps could be removed and transported to an appropriate landfill
or may be left beneath the heap as an added barrier to infiltrating waters.
When regrading and capping heaps with topsoil, the leached ore should
be kept out of natural drainage areas and surface runoff from adjacent land
should be diverted from these areas. These precautions will prevent the
remobilization of any contaminants that may not have received adequate
treatment.
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Verification and Monitoring
Site-specific monitoring programs are integral to all mining operations
and are applicable during all phases. Generally, some water quality
monitoring is required by State regulatory agencies. Surface vater and
ground vater are vulnerable to contamination and the most likely pathways
for transporting contaminants offsite.
The objective of monitoring programs is to ensure that the ground
waters and surface waters are not degraded by effluent originating at the
site. .Different phases of monitoring will focus on different aspects of
the operation. One of the primary concerns of operational monitoring is
the integrity of lined pond surfaces. This can be accomplished by:
Maintenance of a continuous water balance in all ponds
Utilization of containment technology with a leak detection system
Installation of wells dovngradient of the ponds
Monitoring surface vater quality in springs or streams dovngradient
of the facility
Problems encountered during operational monitoring are a function of
the location of a facility. For example, ground water is difficult to
monitor at a facility constracted on highly fractured bedrock.
Post operational monitoring is designed to detect releases that may
originate from solution disposal sites or reclaimed heap areas. The
duration of post operational monitoring should be dependent on climatic and
geologic conditions and the proximity of the site to human habitation.
Questions concerning the amount of monitoring, the length of monitoring
after closure, parameters to be monitored and permissible concentrations
should be addressed on a site by site basis.
After site closure, continued monitoring of any topsoil and vegetation
placed on heaps should also occur at regular intervals.
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ADEQUACY OF EXISTING INFORMATION AND RECOMMENDED REGULATORY SUPPORT
ACTIVITIES
Adequacy of Existing Information
Currently only limited data exist concerning potential leachates from
heap piles during and especially after operations. In particular, the
composition of solid matrices has not been characterized completely. For
example, not all metal cyanide complexes have been characterized
completely. No data exist concerning the correlation of the leachates with
the orevtypes or operational procedures. Only limited data exist
concerning the composition of the ore materials.
In addition to a lack of data concerning the chemical composition of
the vaste, there appear to be no definitive statements concerning the
toxicity of various cyanide complexes to both human and aquatic species.
Inadequate data also exist on the effectiveness of various treatment
techniques. This is especially true for methods used to neutralize leached
ore heaps..
Recommended Regulatory Support Activities
Based on a preliminary review of available information, many data gaps
exist concerning the environmental effects of cyanide. Activities to fill
some of the information needs include:
Standardize analytical techniques based on ion chromotographic
procedures to analyze for all cyanide species in water.
Develop analytical methods to evaluate cyanide species in solid
matrices.
Evaluate correlations between ores and leachate composition.
Evaluate the effectiveness of leached heap neutralization
techniques.
Evaluate the toxicity of various cyanide complexes.
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Collect and compile complete analytical results from heap leachates.
Develop methods to assess the fate and transport of cyanide in the
environment.
SUMMARY AND RECOMMENDATIONS
Cyanidation processes are an integral part of the precious metal mining
industry in this country. Cyanide has been used in this manner for nearly
a century. The exact fate and transport of cyanide in the environment is
difficult to predict but release of cyanide to surface streams has resulted
in fish kills.
The chemistry of cyanide is complex. Cyanide exists as hydrogen
cyanide gas, in solid matrices, or dissolved in aqueous solutions. In
aqueous solutions, the cyanide can exist as free cyanide ions, various
metal complexes, molecular hydrogen cyanide, and thiocyanate. Each of
these species is subject to a variety of mechanisms that control its fate
and transport in the environment. The reactions that cyanide may undergo
in the environment include volatilization, photolysis, hydrolysis,
adsorption, biodegradation, and complexation. Because of the variety of
pathways and reactions, evaluation and control measures must be site
specific. That is, cyanide is only a concern if specific toxic sources,
pathways and receptors are present. At many sites, the conditions to cause
potential problems may not exist. For example, in many arid portions of
the western United States, the surface water pathways do not exist near the
processing sites.
Because of the complex chemistry of cyanide, analytical procedures to
characterize all species in water and solid matrices have not been
standardized or in some cases developed. Likewise, the toxicity of each
species is not well documented.
Many of the current management controls emphasize source elimination by
various treatment steps. These techniques can include direct treatment of
leachate to destroy cyanide (e.g., alkaline chlorination) or neutralization
of cyanide in the leached ore heap (e.g., by hypochlorite solutions).
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Other management controls include proper siting, design and construction.
At all sites, monitoring of ground water, surface water, and final
reclamation are essential.
Based on preliminary reviews of the available data, limited information
exists concerning the fate and impact of cyanide in the environment. The
following activities are recommended to provide additional information:
Standardization of analytical techniques to characterize the major
cyanide species in both water and solid matrices
"Evaluation of methods to predict leachate quality from the heaps
Evaluation of the toxicity of the various cyanide species
Compilation of analytical results from heap ores and heap leachates
Evaluation of the fate and transport of cyanide in the environment
Evaluation of the effectiveness of various treatment techniques for
leached ore heaps
REFERENCES
Hiskey, J.B., 1985. Gold and Silver Extraction: The Application of
Heap-Leaching Cyanidation. Arizona Bureau of Geology and Mineral Tech.
Fieldnotes. Vol. 15, No. 4.
Huiatt, J.L., 1984. Cyanide from Mineral Processing: Problems and
Research Needs. Conf. on. Cyanide and the Environment, December, Colorado
State U., Fort Collins, Coldrado.
Ingles, J.C. and Scott, J.S. 1981. Overview of Cyanide Treatment Methods.
Mining Division, Abatement and Compliance Branch, Environmental
Protection Service - Environment Canada. Hull, Quebec.
Potter, George M., 1981. Some Developments in Gold and Silver Metallury.
Extraction Metallurgy, London 1981 (441 pp.) pages 128-136.
Schiller, J.E. 1983. Removal of Cyanide and Metals from Mineral Processing
Waste Waters. U.S. Dept. of the Interior. Bureau of Mines Report 8836.
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APPENDIX G
TECHNICAL ISSUES PAPER NO. 7
DIRECT HUMAN CONTACT AND MISUSE
ISSUE DEFINITION
Issue Description
Direct human contact and misuse of mining waste usually occurs at
unrestricted sites. Unrestricted sites may be used by children as a play
area or by other individuals for outdoor recreational activities such as
walking or dirt biking. Movement of the waste materials offsite can result
in their misuse as building materials, for children's sandboxes, or as
garden supplements. All of these activities present a direct contact
threat to humans. For example, tailings added to gardening or agricultural
soils can result in crops with elevated metal levels that may pose a health
risk when ingested (Chaney et al. 1984). The severity of the threat to
humans is a function of the toxicity of the waste and the extent of direct
contact or ingestion.
Pathways and Receptors
For a problem to exist, there must be a source of toxic constituents, a
pathway of transport, and a potentially exposed receptor. The pathways for
direct human contact with mining waste are usually through ingestion,
inhalation, or direct skin contact. There is a higher probability of
direct human contact when waste piles are located near residential areas or
population centers. Restricted access may reduce direct contact onsite but
will not control contact with offsite airborne contaminants.
Movement and use of the waste piles for a variety of purposes may
increase the likelihood of direct contact. Movement of waste may increase
inhalation exposure and waste added to gardening or agricultural soils may
increase ingestion df and exposure to contaminants. Waste used for
construction purposes may increase direct contact Or exposure.
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Site Conditions
The occurrence of pathways and resultant human exposure is site-
specific. For example, direct human contact with and misuse of mining
waste will not likely occur given the following conditions:
Waste piles situated in a remote location, far from any residential
area or population center
Access to the mining waste restricted with reliable monitoring and
security systems
Example Sites
Many examples of human contact and misuse exist. Two of the three
examples given below are National Priorities List (NPL) Superfund sites.
At a mining/smelter waste site in Utah, community members removed
tailings from the site for use in vegetable gardens. The site was
marginally fenced and there was no local awareness of potential hazards
associated with mining waste. In another section of the site, wind
transported" tailings offsite. These tailings have accumulated adjacent to
a major transportation route.
A former mining site in Colorado has been commercially developed with
condominiums and trailer parks located on the mining waste. A risk
assessment has concluded that humans (especially children) will be
adversely affected as a result of direct contact and ingestion. The major
constituents of concern are cadmium and lead. Management techniques to
prevent contact (i.e., capping) have been implemented.
Radioactive wastes from a mill in western Colorado were used as
construction material and backfill around houses and schools. Because of
potentially adverse health effects, various remedial measures were
performed. In many cases, the tailings were removed by excavation and
other physical means. Some basements were sealed with polymer materials to
prevent radon exposure.
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ISSUE IDENTIFICATION AND SOLUTIONS
Characterization and Analysis
In addition to evaluating location and access issues, the volume and
specific nature of the vaste must be determined to evaluate the magnitude
of the problem. Characterization issues, including selection of parameters
and analyses, sampling design and methods, and analytical methods, are
discussed below.
Given the potential media and pathways of concern, appropriate
parameters and analyses must be selected. Specific metal and radionuclide
concentrations will be the most appropriate and relevant parameters in most
cases. Particle size distribution should be measured to predict
entrainment of contaminated dust particles (Bohn and Johnson 1983). These
parameters will not only aid in the assessment of public health risks but
also in the assessment of remediation or disposal alternatives.
Sampling design depends on areal extent of mining waste, homogeneity of
the vaste, and cost. A grid sampling program which allows geostatistical
mapping (e.g., kriging) is an accepted method for characterizing a large
area and will save time and money. For smaller or less homogenous areas,
closely spaced transects may be appropriate. In addition, a health based
risk assessment usually requires that most analyses include only surficial
samples (surface to six'inches in depth), i.e., those materials which will
result in exposure.
In most cases, an analytical technique that actually simulates the
amount of metals metabolized by the human body would be the most
appropriate method. However, such methods are currently not standardized.
Therefore, more conservative approaches that yield total concentrations are
typically used. Analytical methods should be comparable to those utilized
to develop potential cleanup standards, criteria or guidelines. For
example, if an acceptable daily intake or reference dose for lead is based
on the total ingested, waste pile analyses must also measure total lead
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present. To determine total metal concentrations, the solid sample must
typically be dissolved by acid digestion or fusion techniques. A variety
of methods exist depending upon the purpose and program under which the
samples were analyzed. For example, the Contract Laboratory Program (CLP)
uses a nitric acid/hydrogen peroxide digestion that typically does not
dissolve silicate minerals. Therefore, the concentrations may be less than
measured with hydrofluoric acid digestion methods. Other nondestructive
techniques such as X-ray fluorescence (XRF) may also be used to measure
total metals (above an atomic number of 10) in solid samples.
Prediction Methods
Evaluating and predicting problems requires a site-specific evaluation
and integration of the following factors:
Contaminant concentrations in waste piles
Volume.of waste
Potential contaminant levels in media and pathways of concern
Location of waste piles relative to residential areas or population
centers
Human access to waste piles
Current or planned removal operations
Particle size distribution in waste piles
Once the concentrations of metals are determined, and the pathways and
receptors identified, a risk assessment can be performed to determine if a
potential health concern exists. To perform the risk assessment, the site-
specific data must be combined with several assumptions commonly used in
estimating exposure to contaminated soil and waste, including the
following:
Children (9 months to 5 years) ingest an average of 500 mg of soil
per day (Schaum 1984, Binder et al. 1985).
People with gardens consume 100 g wet weight of vegetables per day
from the garden (EPA 1981).
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People inhale 20 m3 per day of air.
Respirable particles are 10 microns or less in size (Cowherd et al.
1984).
Other assumptions are usually developed on a site-specific basis. For
example, exposure to dust from dirt bikes may be estimated by integrating
particle size distribution, weight of bikes, speed of bikes, and wind
speed (Kahn and Singh 1986). Most of these assumptions are conservative,
resulting in vorst-case predictions.
Management Controls
The following management controls may be applied during or after vaste
generation:
Treatment or reprocessing of waste to reduce contaminant
concentrations
Watering for dust suppression during removal or disturbance
activities
Capping of vaste to prevent access and dust entrainment
Revegetation of vaste or cap material
Fixation or stabilization of wastes to reduce plant uptake and metal
mobility
Strict control of human access, including a reliable monitoring and
security system
Removal and burial of the waste
Institutional controls to limit access and misuse
Most of these techniques eliminate or reduce the pathvay to the
receptor. In one case, the source term (e.g., metal concentration) is also
potentially reduced.
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Verification and Monitoring
The long term reliability of management techniques is questionable
without a strict maintenance program. Typically, permanent solutions such
as removal, treatment, or fixation/solidification are preferred.
Monitoring may be desirable for permanent solutions to confirm the
integrity of the controls in place. Monitoring controls may include the
following:
Regular fence, cap, and vegetation inspection and maintenance
Patrol or security system
Dust and gas (e.g., radon) monitoring
The exact nature of the monitoring system is site-specific and may
depend on the accessibility and remoteness of the waste site.
ADEQUACY OF EXISTING INFORMATION AND RECOMMENDED REGULATORY SUPPORT
ACTIVITIES
Adequacy of Existing Information
Typically, mining waste has been characterized and a large data base
exists. However, the analytical and sample preparation techniques used for
solid samples have not been consistent. In the human contact and misuse
category, few actual examples exist where documented health problems have
occurred. Most of the documented cases are NPL sites where formal health
assessments have been conducted.
Recommended Regulatory Support Activities
Consistent and standardized methodologies for the analysis of solid
samples should be developed. These methods should emphasize techniques
that provide bio-available concentrations and simulate actual metabolic
uptake.
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In addition, a formal and consistent risk assessment methodology needs
to be developed for evaluating direct contact with or misuse of mining
waste. This methodology must address the following issues:
Contaminant concentrations in mining waste
Location of mining waste relative to human populations
Human access to mining waste
Use or misuse of mining waste
Health risk based criteria or guidelines regarding acceptable
intakes
Models for ingestion and inhalation
0 Analytical methods to measure bio-available metals
Assumptions on ingestion of soils
SUMMARY
Some mining waste can pose a health risk when it is ingested or inhaled
by humans via the following pathways:
Ingestion of contaminated soil (especially children)
Ingestion of vegetables grown in contaminated soil
Ingestion/inhalation of contaminated household dust
Inhalation of contaminated airborne particles
Inhalation of radioactive gases
Direct contact
Direct human contact with and misuse of mining waste is likely to occur
under the following conditions:
Waste piles are located near a residential area or population
center.
Access to waste piles is not strictly controlled.
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o Mining waste is transported to other locations or used for other
purposes.
The problems posed by mining waste requires an accurate
characterization of the nature and extent of contamination and and
assessment of potential for human contact. The location or accessibility of
waste piles often dictate the degree of human contact. Three conditions
must potentially exist before human contact and misuse of mining waste
presents a problem. First, the mining waste must contain toxic
constituents. In addition, a pathway for transport to a human population
must exist and lastly, human receptors must be present. Management
techniques typically involve reducing or eliminating potential pathways to
the receptors. Such techniques include:
Capping of the waste
Fixation or stabilization of the waste
Control of human access through security systems
Removal and burial of the waste
Institutional control to limit access
Consistent and standard analytical techniques for solid samples should
be developed. Techniques should emphasize procedures that yield bio-
available concentrations. In addition, a formal and consistent risk
assessment methodology needs to be developed for evaluating direct contact
with a misuse of mining waste. The methodology should allow for some
flexibility and professional judgment based on-site specific conditions.
REFERENCES
Binder, S.; Sokal, D.; and Maughan, D. 1985. Estimating the Amount of Soil
Ingested be Young Children Through Tracer Elements. Draft. Centers for
Disease Control. Atlanta, Georgia. July 31.
Bohn, R.R. and Johnson, J.D. 1983. Dust Control in Active Tailings Ponds.
Bureau of Mines. Department of the Interior. Contract J0218024. February.
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June 22, 1987
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Chaney, R.L.; Sterrett, S.B.; and Mielki, H.W. 1984. The Potential for
Heavy Metal Exposure from Urban Gardens and Soils. In Preer, J.R., Ed.
Proceedings of a Symposium on Heavy Metals in Urban Gardens. University
of the District of Columbia Extension Service, pp. 37-84.
Cowherd, C. Jr.; Muleski, G.E.; Englehart, P.J.; and Gilette, P.A. 1984.
Rapid Assessment of Exposure to Particulate Emissions from Surface
Contamination Sites. Office of Health and Environmental Assessment,
Washington, D.C. February.
Khan, A. and Singh, L. 1986. Fugitive Emissions and their Role in New
Source Review. Presented at the 79th Annual Meeting of the Air Pollution
Control Association. Minneapolis, Minnesota. June 22-27.
Schaum, J.L. 1984. Risk Analysis of TCDD Contaminated Soil. Office of
Health and Environmental Assessment. U.S. Environmental Protection
Agency. Washington, D.C. EPA 600/8-84-031. November.
U.S. Environmental Protection Agency (EPA). 1981. Health Assessment
Document for Cadmium. Environment Criteria and Assessment Office.
Research Triangle Pard, North Carolina. EPA 600/8-81-023. October.
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APPENDIX H
TECHNICAL ISSUE PAPER NO. 8
CATASTROPHIC SLOPE FAILURE
ISSUE DEFINITION
Issue Description
Mining operations can result in the formation of slopes composed of
earth, rock, tailings, mine wastes, or combinations of materials. Slope
failure may result in endangerment to the environment or human health.
Slope failure results from exceeding the internal mass strength of the
materials composing the slope. This occurs when the slope angle is
increased to a point where the internal mass strength can no longer
withstand the excess load resulting from oversteepening or overloading of
the slope. When the driving forces associated with oversteepening exceed
the internal resisting forces, the slope fails and the materials move to a
more stable position.
Environmental problems associated with slope failures occur when the
failure of a slope results in the release of toxic or reactive materials
into environments where reaction can occur or where direct exposure
results. The release of these materials and their exposure to potential
receptors are addressed in the other technical issues papers (e.g., Mobile
Toxic Constituents/Air and Water; Technical Issue Papers Nos. 2 and 3).
Example Sites
A tailings pile in Colorado was supported by a timber crib retaining
wall constructed during the late 1800's. As time progressed, the timbers
deteriorated, resulting in partial failure of the wall and exposing
processed tailings. The tailings formed acid when mixed with water,
resulting in the dissolution of heavy metals. A creek upstream of a major
water source for a large metropolitan area flowed along the base of the
retaining wall.
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As tailings were released into the creek, it immediately became acidic,
dropping from a pH of 6 to a pH of 2, significantly affecting aquatic life
in the stream and potentially maintaining dissolved heavy metals in
solution as far down as some of the municipal receptors downstream.
In Pennsylvania, a tailings pile adjacent to a small stream failed,
resulting in the temporary damming of the stream. As the waters backed up
behind the dam created by slope failure, a flood potential was created;
when the dam was breached, a large quantity of water flowed downstream
causing extensive damage.
A well known example of slope failure was the collapse that occurred at
Splitrock, New Mexico. The manmade tailings dam was constructed of
naturally occurring materials, including some calcium carbonate. The acid
tailings placed behind the dam dissolved the calcium carbonate and weakened
the dam foundation, ultimately leading to failure. The downstream areas
were contaminated with acidic tailings and radioactive materials.
ISSUE IDENTIFICATION AND SOLUTIONS
Mine slopes fall into two categories: natural or cut slopes and
manmade or filled slopes. The methods of slope formation reflect the
potential hazards associated with each.
Natural or cut slopes are created by the removal of overburden or ore
which results in the creation of or alteration to the surface slope of
undisturbed native materials. Changes to an existing slope may create
environmental problems associated with increased erosion, rapid runoff,
changes in wildlife patterns and the exposure of potentially reactive
natural ore materials.
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Manmade or filled slopes are created by dumping or piling of
overburden, tailings, waste rock or other materials. Often these materials
are toxic, acid forming, or reactive in their existing condition, and slope
failure can result in direct release or direct exposure of these materials
to the surrounding environment.
Characterization
Catastrophic slope failure is characterized by "relatively large and
relatively rapid movements associated with failure of at least some of the
material comprising the slope or its foundation, as distinct from the slow,
long term slope movements commonly referred to as creep" (Perloff and
Baron 1976). Perloff and Baron (1976) characterize basic modes of slope
failure as:
Falls "Falls are distinguished by a rapidly moving mass of
metal (rock or soil) that travels mostly through the
air, with little or no interaction between one moving
unit and another"
Slides Slides "result from shear failure among one or more
surfaces. The sliding mass may move as a relatively
intact body or may be greatly deformed ... geologic
conditions play a major role in determining the slope
of the failure surface ..."
Flows "Flows are characterized by movements in the displaced
mass that resemble those of a viscous kind".
Terzahgi (1950) identified two of the principal causes of slope failure
as "internal" and "external".
"External causes are those which produce an increase of the
shearing stress" while not affecting the "shearing resistance of
the material comprising .. the slope". (Perloff and Baron,
1976). This is most commonly characterized by continued dumping
on an acutely steep waste pile or by erosion or removal of
materials at the toe of a tailings dam.
"Internal causes are those which lead to a failure without any
change in external conditions". This mode of failure is
characterized by the reduction of resistive shear strength
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through changes in pore pressure often caused by earthquakes
(Perloff and Baron 1976). Another example is the dissolution of
calcium carbonate slope materials by acidic flows.
Methods for slope stability analysis were developed in the 18th and
19th centuries. The basic assumptions for analysis have not changed and
include:
"1. Failure of an earth slope occurs along a particular sliding surface.
That is ... the failure can be represented as a two-dimensional plane
problem.
2. The failure mass moves as an essentially rigid body, the deformations
of which do not influence the problem.
3. The shearing resistance of the soil mass at various points along the
failure surface is independent of the orientation of the failure
surface: (e.g., that is, the strength properties are isotropic.
4. The factor of safety is defined in terms of the average shear stress
along the potential failure surface and the average shear strength
along this surface, rather than the local values at particular points.
Thus, the shear strength of the soil may be exceeded at some point
along the failure surface whereas the computed factor of safety may be
larger than 1.0." (Perloff and Baron 1976).
Figure H-l illustrates the basic mechanics of slope stability analysis.
For the defined failure slope, the driving force is the mass weight (W) of
the failure mass treated as a movement about point "A". Resisting forces
result from the shear strength of the soil mass. The shear strength is
composed of two parts, including cohesion, which results from interparticle
electro-chemical bonding, and interparticle friction, which is a function
of the normal force (N) and the angle of internal friction (0) (a physical
characteristic of the particulate mass). The presence of water within the
slope mass plays a significant part in the reduction of internal mass
strength. A Factor of Safety (FS) is defined as the ratio of resisting
forces to driving forces as shown below:
Resisting Forces
FS =
Driving Forces
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POINT A
FAILURE SURFACE
COHESION (C)
0 = ANGLE OF INTERNAL
FRICTION
NORMAL FORCE (N)
DRIVING FORCES
x W
RESISTING FORCES
L C +E N tan 0
L
FIGURE H-l. BASIC MECHANICS OF SLOPE STABILITY ANALYSIS
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If FS is less than or equal to 1, the slope is unstable. I £ FS is
greater than 1, the slope is stable.
Analysis
For slope stability to create an environmental problem, two conditions
must be assessed:
1. Is the setting of the slope such that failure vould result in a
hazard or in the release of toxic materials?
2. Is the slope stable?
A number of theories and methods of analysis for slope stability have
been developed and are commonly used in the practices of geotechnical and
mining engineering. All methods result in an assessment of the factor of
safety. Data from site-specific materials may be used in the stability
analysis for that particular site.
Prediction
The design factor of safety should be selected based on the potential
for exposure should a failure occur. For instance, if the slope is located
immediately adjacent to a stream serving as a major water supply, then an
appropriate factor of safety (e.g., 2.0) should be selected and the slope
should be designed to meet this criteria. However, if the slope is located
in a contained, controlled area where a failure results in no risk, of
exposure, then a lower factor of safety (e.g., 1.2) vould be acceptable.
Control
For new mine operations, the stability analysis should be reviewed
prior to permitting. This is currently required for open-pit coal mine
operations through the Surface Mining Act of 1979. Similar requirements,
coupled with evaluation of environmental setting and environmental hazard
should be developed for non-coal mining operations. For abandoned slopes,
site-specificstability assessments and investigations may be conducted.
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Monitoring and Verification
A number of systems have been developed for monitoring movement of
slopes. Inclinometers and slope indicators can be built into new slopes as
part of construction or installed in existing slopes. Frequent monitoring
of inclinometers and slope indicators can track the movement or lack, of
movement within a slope mass. The key becomes assessing the proper
locations for monitoring systems and in interpreting the results of the
monitoring systems. This monitoring program should be coupled with
ground water monitoring to assess seepage or changes of seepage within the
slope mass.
Since the stability of a slope is dependent on its physical geometry,
conventional surveying of slope angles and height would assist in
evaluating the effect of mining operations on the structure of the slope.
ADEQUACY OF EXISTING INFORMATION AND RECOMMENDED REGULATORY SUPPORT
ACTIVITIES
Adequacy of Information
The overriding question concerns the extent of actual problems created
by unstable slopes. What is the probability of a slope failure occurring
and what is the probability of that slope failure resulting in
environmental endangerment? The actual degree of the problem should be
assessed.
The second major issue revolves around evaluation of operational
effects; that is, how often does a mining operation exceed the design
criteria of associated slopes, resulting in the failure of that slope?
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Recommended Regulatory Support Activities
It is virtually impossible to achieve consensus on a method for
evaluating slope stability among geotechnical and mining experts in the
country. In addition, the methods for evaluation tend to be more suited to
different applications and different geologic conditions. Therefore, some
flexibility in the assessment and some professional judgment are desirable.
It is recommended that a checklist be developed to identify a number of
minimum steps that must be addressed in the design, maintenance, and
closure of facilities where unstable slopes pose a potential environmental
problem. This checklist should include verification of:
Proper evaluation of the physical parameters of the particulate
media forming the slope
Proper assessment of existing and potential ground water surfaces
developed as a result of slope construction
Seismic evaluation
Regional assessment of potential receptors and modes of transport of
hazardous releases
Analytical assessment of the stability of the slope in the design,
operational, and post closure modes
A monitoring and reporting program to verify slope stability
SUMMARY AND RECOMMENDATIONS
Catastrophic slope failure results in an environmental or human health
problem when toxic materials are released from the failure and when the
failure occurs in an area where such a release results in a direct pathway
to receptors.
Slope failure occurs when the geometry of the slope reaches an unstable
configuration, based on the physical (strength) properties of the materials
composing the slope or when the internal mass strength is reduced by
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seismic or chemical action. Numerous methods of slope stability assessment
exist, all of which are dependent on accurate evaluation of the physical
properties that contained the strength of the slope mass.
The simplest method for controlling catastrophic failure is to assure
proper initial design, construction and operational and post-closure
maintenance of the slope. In addition, a monitoring program may be
necessary to verify that the slope remains immobile and that internal
conditions do not change the properties of the materials composing the
slope.
A number of methods of monitoring slope movement exist, ranging from
basic surveying through actual slope instrumentation. Those methods are
suitable for post-closure monitoring as well as operational monitoring.
Additional regulatory support in the evaluation of the actual extent
that slope instability creates an environmental hazard is recommended. A
minimum design standard (checklist) would be a useful tool for future
control design and planning.
REFERENCES
Golden, H.Q. 1979. Soil and Rock Mechanics Problems in Mining. Proceedings
of the Sixth Panamerican Conference of Soil Mechanics and Foundation
Engineering. General Report, Session 1. Lima, Peru. CPMSIC. Ap. 11076.
Perloff, W.H. and Baron, W. 1976. Soil Mechanics. New York: The Ronald
Press Company.
Terzaghi, K. 1950. Mechanics of Landslides. In Application of Geology to
Engineering Practice. Berkey Volume. Geological Society of America.
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APPENDIX I
TECHNICAL ISSUE PAPER NO. 9
COMMON TECHNICAL ISSUES
ISSUE DEFINITION, IDENTIFICATION, AND SOLUTION
Each of the previous eight issue areas had specific identified
technical concerns. Examination of these concerns reveals that many of
them are common to the majority of issues. Some of the common technical
issues include development of the following:
1. Sampling techniques to insure representative samples
2. Standardized preparation and analytical techniques to insure
consistent and meaningful results
3. Methodologies to simulate and model fate and transport of the
constituents of concern
4. Methodologies to address the potential risk to receptor populations
The first two common issues focus on the accurate and representative
characterization of the source. The third issue focuses on characteriza-
tion and prediction of the transport pathway. The last issue emphasizes
evaluation of the risk to receptors. Therefore, all common technical
issues relate to the definition of the three conditions necessary at a site
for evaluation of risks to human health and the environment. These are:
A potential source of contaminants
A pathway to transport the contaminants
A receptor, resulting in potential exposure
These conditions have been discussed previously in each of the major
issues areas. These conditions further emphasize that the overall
regulatory decision process must be site-specific and risk-based.
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Each of the common technical issues identified above are discussed
briefly in the following sections. This paper will be expanded as
additional common technical issues are identified.
Sampling Techniques
Techniques for obtaining representative samples will benefit from
additional development and standardization. In particular, the large
volumes of solid materials existing at mining waste sites result in unique
sampling problems. The nature of mining waste also results in the
opportunities to apply techniques already used in the mining industry. For
example, geostatistical techniques used for defining ore grades can also be
used to define the "grade" or concentration of contaminants in waste. Even
more important, the geostatistical tools can also be used to evaluate the
level of confidence of the concentrations at a given location. These
methods can then be used to accurately assess the number of samples
necessary to achieve a desired level of confidence. On the negative side,
these methods can indicate that extremely large numbers of samples are
necessary to accurately characterize a non-homogeneous solid waste site.
Besides the evaluations of numbers of samples, further definition is
needed regarding (1) the type of sampling equipment, (2) size of samples
(volumes to be collected), and (3) sample preservation techniques.
Analytical Techniques
Methods for obtaining accurate and consistent concentrations from the
laboratory analyses will also benefit from additional development and
standardization. The methods to digest and analyze solid samples from
mining waste sites should specifically be refined. As discussed in the
previous issue areas, some examples include:
Digestion techniques to represent bio-available constituents
Procedures to accurately predict acid generation potential
Methods to determine cyanide complexes in solid samples
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Methods to characterize the complete chemical composition of the
samples
Procedures to accurately simulate the leachability of solid samples
in the environment
In addition, (1) the necessary types of analyses to be performed on
mining wastes and other media they affect, (2) frequency of sampling, and
(3) interpretation of results for various parameters based upon temporal
changes in the waste pile and affected media, deserve further attention, as
discussed below.
Modeling Techniques
Techniques for accurately evaluating and predicting the fate and
transport of chemical constituents in the environment merit additional
development and standardization. In addition to the analytical techniques
to simulate leaching (discussed above), procedures to simulate transport in
the environment are needed. These techniques may include batch and/or
column tests. Potential reaction mechanisms and concentration changes can
be modeled using a thermodynamic-based geochemical program. Hydrological
modeling can be used to evaluate and predict water flow and mass transport.
These two types of models are often coupled to accurately predict transport
of chemicals in the environment. Although the need exists to standardize
computer models, professional judgment and site-specific models may often
yield useful, defensible results.
Risk Assessment Techniques
A consistent method to evaluate exposure and risk to receptor
populations would gain from additional refinements. Much progress has been
made in the last few years in developing risk assessment methods. These
methods need to be specifically modified so that they can be used to
accurately evaluate mining waste. The methodology should incorporate the
methods, models and approaches discussed in the previous paragraph to
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June 22, 1987
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arrive at a consistent approach that is site-specific. The compilation of
Records of Decision (RODs) for various risk action levels at CERCLA mining
waste sites are a good source of background data.
OTHER RECOMMENDED SUPPORT ACTIVITIES
In addition to the major common technical issues discussed above, some
other less common issues also exist. These include the development of
consistent criteria and screening techniques.
As noted above, these criteria may in many cases result from the risk
evaluation. Screening techniques are necessary in the areas of chemical
analyses and risk evaluation. That is, relatively sensible, cost-effective
"screening" methods should be developed to use in Tier 1 and Tier 2
evaluations under the proposed conceptual program design (Section 4.A).
Once the approach and methods discussed above have been developed, they
must be evaluated using actual case data. That is, the models must work
and be proven to work with actual site-specific data. This is the ultimate
check of the selected methods.
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