&EPA
United States
Environmental Protection
Agency
Ore Mining and Dressing Preliminary Study
Report
September 2011
EPA-820-R-10-025
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CONTENTS
Page
1.0 INTRODUCTION 1-1
1.1 Key Definitions 1-1
1.2 Key Findings 1-4
1.2.1 Process Wastewater Discharges 1-4
1.2.2 Storm water Discharges 1-4
1.3 Overview of Remainder of Report 1-4
1.4 Introduction References 1-5
2.0 DATA SOURCES 2-1
2.1 EPA's Databases 2-2
2.1.1 Toxics Release Inventory (TRI) 2-2
2.1.2 Discharge Monitoring Report Data from the Permit Compliance
System (PCS) and the Integrated Compliance Information System
for the National Pollutant Discharge Elimination System (ICIS-
NPDES) 2-2
2.1.3 Envirofacts 2-4
2.1.4 Enforcement and Compliance History Online (ECHO) 2-4
2.1.5 Total Maximum Daily Load (TMDL) Studies 2-4
2.1.6 Stormwater Data 2-4
2.2 Data from States and EPA Regional Offices 2-5
2.3 Non-EPA Data Sources 2-5
2.3.1 U.S. Economic Census 2-5
2.3.2 USGS Minerals Yearbook and Mineral Commodity Summaries 2-5
2.3.3 Leadville Mine Drainage Tunnel (LMDT) Treatment Plant
Information 2-6
2.4 Data Sources References 2-6
3.0 PROFILE OF THE ORE MINING AND DRESSING POINT SOURCE CATEGORY 3-1
3.1 Ore Mining and Dressing Point Source Subcategories 3-1
3.2 Estimates of the Number of Active Mines 3-2
3.3 Ore Mining Processes 3-5
3.4 Profile of the Ore Mining Category References 3-5
4.0 REGULATORY FRAMEWORK FOR ORE MINING DISCHARGES 4-1
4.1 Overview of NPDES Permitting 4-1
4.2 NPDES Permitting of Process Water and Stormwater from Ore Mines 4-2
4.3 Distinction Between Technology-Based Permit Limits and Water Quality-
Based Permit Limits 4-4
4.4 Ore Mining Regulatory Framework References 4-4
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CONTENTS (Continued)
Page
5.0 REVIEW OF TMDL STUDIES TO DETERMINE THE EXTENT TO WHICH ORE MINES MAY
BE A CAUSE OF WATER QUALITY IMPAIRMENTS 5-1
5.1 EPA's Approach to Screening TMDL Studies 5-1
5.2 Results of Screening the TMDL Studies 5-2
5.3 Ore Mining Water Quality Impact References 5-2
6.0 PROCESS WATER DISCHARGES 6-1
6.1 Process Water Discharges References 6-2
7.0 STORMWATER ANALYSIS 7-1
7.1 Quality Procedures Used to Create Analysis Spreadsheets 7-1
7.2 Stormwater Monitoring Data for Arizona 7-2
7.3 Stormwater Monitoring Data for Montana 7-4
7.4 Conclusions 7-6
7.5 Stormwater Analysis References 7-7
8.0 HIGH DENSITY SLUDGE TREATMENT TECHNOLOGY REVIEW 8-1
8.1 Background of High Density Sludge Recycling 8-1
8.2 Overview of the HDS Process 8-2
8.3 Prevalence of the HDS Process 8-2
8.4 Permit Requirements and Level of Treatment Required for the HDS System.... 8-4
8.5 Observations about HDS 8-6
8.6 High Density Sludge Treatment Technology References 8-6
Appendix A: NUMERIC LIMITS SPECIFIED IN THE ORE MINING EFFLUENT
GUIDELINES
Appendix B: SUMMARY OF PERMITTED DISCHARGES COVERED BY THE ORE
MINING POINT SOURCE CATEGORY
Cover photos clockwise from top left: Bagdad pit; tailings embankment for the Mammoth
Tailings Impoundment; pregnant leach solution pond at the toe of the Bagdad Mine's leach pad;
saleable copper cathode produced from Morenci's SXEW plant. All photos were taken during
EPA's site visits to Freeport McMoran copper mines in Arizona during August 2009 (see Site
Visit Report: Arizona Copper Mines [DCN 07219]).
11
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LIST OF TABLES
Page
1-1 Categories of Discharges from Mining Operations 1-3
2-1 Primary Data Sources for the Ore Mining Preliminary Study 2-1
2-2 Summary of Ore Mining Facilities with Data in EPA's PCS and ICIS/NPDES
Databases 2-3
2-3 Summary of Responses to EPA's Information Request 2-5
3-1 Ore Mining Category Subcategory Applicability 3-1
3-2 Estimated Number of Facilities in the Ore Mining Category 3-3
4-1 Comparison of Monitoring Requirements for Western States and Federal General
Stormwater Permits 4-5
5-1 TMDL Studies with Information on Active and Recently Closed Ore Mines 5-3
6-1 2007 Discharge Summary for the Ore Mining Category 6-1
7-1 Stormwater Monitoring Data Available for Arizona Ore Mines 7-3
7-2 Summary of Arizona Stormwater Monitoring Data, in mg/L 7-4
7-3 Summary of Stormwater Monitoring Data Available for Montana Ore Mines 7-5
7-4 Summary of Montana Stormwater Monitoring Data, in mg/L 7-6
8-1 Permit Limits for HDS Systems Treating Discharges Associated with Ore Mining
(Units are in mg/L) 8-5
in
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LIST OF FIGURES
Page
4-1 Example of Discharge Classification Depending on Wastewater Source and
Management (U.S. EPA, 2003) 4-3
8-1 Simplified Schematic of the HDS Process (Leon and Zick, 1997) 8-2
IV
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Section 1.0 - Introduction
1.0 INTRODUCTION
The purpose of this report is to summarize the analytical approach, research activities,
and findings of the Ore Mining and Dressing Preliminary Study that EPA conducted to examine
why discharge concentrations controlled under pollutant limitations in the Ore Mining and
Dressing Effluent Limitations and Guidelines (ELG) (40 CFR Part 440) ranked relatively high
compared to other industries in the 2002 through 2008 304(m) effluent guidelines program plans.
The purpose of the study was to identify, collect, and review readily available information to
determine whether additional analysis or revision of 40 CFR Part 440 might be warranted.
The main focus of the preliminary study was on active mines covered under 40 CFR Part
440 Subpart J: "Copper, Lead, Zinc, Gold, Silver, and Molybdenum Ores." These types of mines
comprise approximately 76 percent (263) of the approximately 345 ore mines in the United
States. Approximately 294 mines currently have National Pollutant Discharge Elimination
System (NPDES) water discharge permits. There is a discrepancy between the total number of
mines and the number of mines with NPDES permits because not all mines have water
discharges. The approximately 1,870 placer mines, covered under 40 CFR Part 440 Subpart M,
were not examined by this study because they employ mining practices and produce wastewater
streams that are fundamentally different from mines covered under the other subparts of 40 CFR
Part 440.
The preliminary study examined information pertaining to the two types of wastewater
discharged by ore mines: process wastewater (including mine drainage) and stormwater. Process
wastewater is covered under 40 CFR Part 440. Stormwater is not covered under 40 CFR Part 440
unless it is commingled with process wastewater prior to discharge to a surface waterbody. The
comprehensiveness of the preliminary study was limited by incomplete national-level process
wastewater discharge data, and the lack of any nationally representative stormwater data.
To facilitate this study, EPA identified and collected existing discharge monitoring data,
assessed mine-specific process wastewater discharge information, reviewed available Total
Maximum Daily Load (TMDL) reports, reviewed mine site stormwater discharge information for
19 mines in Arizona and Montana, and reviewed an industrial wastewater treatment technology
known as high density sludge recycling.
1.1 Key Definitions
This subsection clarifies key terms used in this report.
Mining, Dressing (Beneficiation), and Mineral Processing
Ore mining consists of three major types of operations: mining, dressing, and mineral
processing. 40 CFR Part 440 pertains to wastewater from mining and dressing activities, but not
from mineral processing, which is covered under 40 CFR Part 421.
The term "mining" is specific to the process of extracting ore from the earth, which
mostly involves either open pit excavation or deep mining. The term "dressing," no longer used
by the ore mining industry, has been replaced by the term "beneficiation." They mean the same
thing, however, which is the initial attempt to liberate and concentrate the mineral from the
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Section 1.0 - Introduction
mined rock. Beneficiation operations include crushing, grinding, washing, dissolution,
crystallization, filtration, sorting, sizing, drying, pelletizing, briquetting, or roasting in
preparation for leaching, gravity concentration, magnetic separation, electrostatic separation,
flotation, amalgamation, and heap, dump, vat, tank, and in-situ leaching.
Mineral processing operations generally follow beneficiation and include techniques that
change the chemical composition of the ore mineral, such as ion exchange, solvent extraction,
smelting, electrolytic refining, and acid attack or digestion. The physical structure of the mineral
is often destroyed, producing products and waste streams that are not earthen in character,
bearing little or no resemblance to the materials that entered the operation.
Overburden, Waste Rock, and Tailings
The distinction between overburden and waste rock determines how these materials are
managed. Overburden is any non-mineralized material that overlies an ore body. Waste rock is
mineralized material that has been mined but lacks sufficient mineral content and value to
warrant further processing.
Because overburden is non-mineralized, overburden management is generally less
rigorous. Waste rock is generally placed in engineered structures with stormwater run-off
controls in a part of the mine away from the ore body. Overburden piles may or may not need
stormwater controls.
Wastes from beneficiation processes are known as tailings. If they contain sufficiently
high concentration of minerals, tailings piles may be leached to recover additional dissolved
minerals. Any potential discharges from tailings piles, or from leachate ponds at the base of
tailings piles, are covered under 40 CFR Part 440.
Total waste (waste rock and tailings) produced during the extraction and beneficiation of
minerals can range from 10 percent of the total material removed from the earth (potash) to more
than 99.99 percent (gold).
Active and Inactive Mines
40 CFR Part 440 defines "active mining area" as the place where work or other activity
related to the extraction, removal, or recovery of metal ore is being conducted, except, with
respect to surface mines, any area of land on or in which grading has been completed to return
the earth to desired contour and reclamation work has begun.
Active mines, moreover, produce a saleable product, whether or not extraction operations
at the site are currently underway. For example, a mine where extraction has stopped, but heap
leaching of ore is being performed is considered an active mine. In contrast, inactive mines are
those that are not currently producing a saleable product. Inactive mines may be temporarily
closed, undergoing reclamation and closure, permanently closed, or abandoned. Estimates of the
number of abandoned mines vary. The United State Geological Survey's Abandoned Mine
Lands Initiative uses the estimate of 557,650 abandoned mine sites in 32 states compiled by the
Mineral Policy Center, an environmental research and advocacy group (Lyon and others, 1993.)
1-2
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Section 1.0 - Introduction
The Superfund Final National Priority List1 of 1277 Superfund sites includes
approximately 23 mines.
Process Wastewater, Mine Drainage, and Stormwater
There are three types of wastewater discharged by ore mines: process wastewater, mine
drainage, and stormwater. Process wastewater and mine drainage are covered under 40 CFR Part
440. Stormwater is not covered under 40 CFR Part 440 unless it is commingled with process
wastewater and mine drainage prior to discharge to a surface waterbody. Table 1-1 presents legal
definitions of these terms.
Table 1-1. Categories of Discharges from Mining Operations
Waste Stream
Definition
Process wastewater
"...any water which, during manufacturing or processing, comes into direct contact with or
results from the production or use of any raw material, intermediate product, finished
product, byproduct, or waste product." (40 CFR 122.22)
Mine drainage
Mine drainage includes water drainage from refuse, storage piles, wastes, rock dumps, and
mill tailings derived from the mining, cleaning, or concentration of metal ores. Mine
drainage may include process water still contained in the mine. Stormwater runoff and
infiltration can contribute to mine drainage.
"...any water drained, pumped, or siphoned from a mine." (40 CFR 440.132)
Industrial stormwater
Stormwater means rain water runoff, snow melt runoff, surface runoff, and surface
drainage. Industrial facilities are required to obtain permit coverage for stormwater if they
have a point source stormwater discharge associated with an industrial or commercial
activity from their property either directly to waters of the United States or to a municipal
separate storm sewer system.
"...the discharge from any conveyance which is used for collecting and conveying storm
water and which is directly related to manufacturing, processing or raw materials storage
areas at an industrial plant. ... (40 CFR 122.26)
Source: Adapted from EPA and Hardrock Mining: A Sourcebook for Industry in the Northwest and Alaska (EPA,
2003).
Toxic Weighting Factors and Toxic Weighted Pound Equivalents
Chemical pollutants discharged to surface water have different toxicities. EPA
normalizes the toxicities of the various pollutants in a waste stream by multiplying the amount of
each chemical by a Toxic Weighting Factor (TWF). The TWF for a chemical is a normalizing
weight based on its toxicity relative to copper, which is commonly found in industrial
wastewater. For example, cadmium, which is more toxic than copper, has a TWF of 2.6, whereas
nickel, which is less toxic than copper, has a TWF of 0.11. EPA's TWFs database currently
contains toxic weighting factors for more than 1,900 chemicals.
Using TWFs, EPA estimates pollutant discharges on a constant toxicity basis expressed
as Toxic Weighted Pound Equivalents (TWPE). TWPE values allow EPA to rank and compare
facilities and industries that discharge waste streams with different toxicities. For example, a
facility discharging 40 pounds of cadmium (40 x 2.6 = 104) and 20 pounds of nickel (20 x 0.11
Available online at http://www.epa.gov/superfund/sites/npl.
1-3
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Section 1.0 - Introduction
= 2.2), releases 106.2 toxic weighted pounds to surface water. Another facility, discharging 30
pounds of cadmium (30 x 2.6 = 78) and 100 pounds of nickel (150 x 0.11 = 16.) releases 94.5
toxic weighted pounds to surface water, and would thus rank lower than the previous facility
(ERG, 2005).
1.2 Key Findings
This section presents key findings of the Ore Mining Preliminary Study.
1.2.1 Process Wastewater Discharges
EPA found that in 2007, the most recent year for which quality-checked data are
available, approximately two percent of the estimated 294 ore mining facilities with NPDES
permits were responsible for approximately 90 percent of toxic weighted discharges by the
industry2. Given that a small percentage of active mines account for the majority of toxic
weighted discharges, discharge issues are best addressed through permitting, compliance, and
enforcement activities rather than revision of 40 CFR Part 440.
1.2.2 Stormwater Discharges
The only readily available data for stormwater discharges from active mines that EPA
was able to identify were for 19 mines in Arizona and Montana. The data were too limited,
however, to support regional or national conclusions about stormwater discharges at ore mining
sites. Statistically representative sampling of stormwater discharges would be needed to better
assess the effectiveness of stormwater controls.
EPA used available information from Total Maximum Daily Load (TMDL) reports as an
indicator of the extent to which stormwater from active mines may be a cause of water quality
impairment. TMDL information was used because of the lack of nationally available stormwater
discharge data for mining sites. TMDL reports list the sources of impairment in watersheds, and
set point source and nonpoint source load limitations for waterbodies that have been determined
to be impaired by EPA or by authorized state permitting authorities. EPA conducted a keyword
search of 7,760 TMDL reports and found only seven instances where active ore mines were
named among the sources within impaired watersheds. None of the TMDL documents, however,
definitively stated that impairments resulted from active mines.
Interviews with EPA regional staff did not identify sites where stormwater discharges
from active mining sites are a concern, except for a couple of mines in EPA Region 8 where
stormwater retention ponds are sometimes inadequate to contain runoff from spring snow melt.
1.3 Overview of Remainder of Report
The remainder of this report is organized into the following sections:
• Section 2.0 summarizes how EPA identified and collected data to evaluate the ore
mining effluent guidelines.
2 Of the 54 facilities with available discharge data, 7 (13 percent) were responsible for 90 percent of the toxic
weighted discharges.
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Section 1.0 - Introduction
• Section 3.0 provides a summary of the Ore Mining Category including a
description of industry sectors as well as a facility list.
• Section 4.0 summarizes the laws and regulations that control operations in the Ore
Mining Category.
• Section 5.0 discusses EPA's review of Total Maximum Daily Load (TMDL)
studies relevant to the Ore Mining Category Review.
• Section 6.0 discusses EPA's analysis of process wastewater discharges from the
Ore Mining Category.
• Section 7.0 discusses EPA's analysis of monitoring data for stormwater
discharges from ore mining operations.
• Section 8.0 discusses EPA's evaluation of the High Density Sludge (HDS)
treatment technology.
1.4 Introduction References
1. Lyon, J.S., Billiard, T.J., and Bethell, T.N. 1993. Burden of Gilt. Mineral Policy Center,
Washington, D.C.
2. U.S. EPA. 2004. Technical Support Document for the 2004 Effluent Guidelines Program
Plan. EPA-821-R-04-014. Washington, DC (December).
3. Western Mining Action Project. 1998. Memo Re: Petition and Comment on Notice of
Proposed Effluent Guidelines Plan (63 Fed. Reg. 29203-29213, May 28, 1998). Boulder,
CO.
4. NMA. 2010. Comments on Preliminary 2010 Effluent Guidelines Program Plan. EPA-
HQ-OW-2008-0517-0550. Washington, DC (February).
5. U.S. EPA. 2003. EPA and Hardrock Mining: A Sourcebook for Industry in the Northwest
and Alaska. Seattle, Washington (January).
6. ERG. 2005. Draft Toxic Weighting Factor Development in Support of CWA 304(m)
Planning Process. Lexington, MA (July).
1-5
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Section 2.0 - Data Sources
2.0 DATA SOURCES
This section summarizes the available information that EPA identified and reviewed to
better understand process water and stormwater discharges by the ore mining industry. More
specifically, EPA reviewed information to do the following:
• Identify and determine the number of ore mining facilities in the U.S.;
• Identify mining facilities with NPDES permits;
• Characterize discharge pollutant concentrations;
• Estimate discharge loads and Toxic Weighted Pound Equivalent Loads; and
• Assess potential impacts of discharges on surface water quality.
Table 2-1 summarizes the main data sources used for the Ore Mining Preliminary Study.
Table 2-1. Primary Data Sources for the Ore Mining Preliminary Study
EPA National Databases'
Toxics Release Inventory
Discharge Monitoring Report (DMR) Databases
- Permit Compliance System (PCS)
- Integrated Compliance Information System and National Pollutant Discharge Elimination System (ICIS-
NPDES)
- Envirofacts
- DMR Pollutant Loading Tool
Enforcement and Compliance History Online (ECHO)
Total Maximum Daily Load (TMDL) Studies
Data from EPA Regional Offices and States
Stormwater monitoring data
- Arizona Department of Environmental Quality
- Minnesota Pollution Control Agency
Facility lists
- EPA Region 8
- EPA Region 9
- Missouri Department of Natural Resources
- Nevada Division of Environmental Protection
- New Mexico Environment Department
Non-EPA Data
• U.S. Economic Census
• USGS Minerals Yearbook and Mineral Commodity Summaries
• Monitoring data and cost information for the Leadville Mine Drainage Tunnel Treatment Plant
a - For more information on how EPA uses and processes these data for the Annual Review, see EPA's Technical
Support Document for the Annual Review of Existing Effluent Guidelines and Identification of Potential New Point
Source Categories (EPA, 2010).
Limitations in data quality and availability precluded EPA from determining the exact number of
facilities in each subcategory, or completely characterizing discharges from some ore mining
facilities. The data sources used for the Ore Mining Preliminary Study have the following
general limitations:
2-1
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Section 2.0 - Data Sources
• The data may not reflect current conditions because the most recent data are
typically from 2006; and
• Discharge data are incomplete. Not all monitoring data from all states are reported
to EPA national databases. Moreover, monitoring is not required for all pollutants
that may be present in waste.
2.1 EPA's Databases
2.1.1 Toxics Release Inventory (TRI)
EPA reviewed ore mining water discharge information from the 2007 TRI database,
which is the most recently available year. The TRI database was of limited usefulness for the Ore
Mining Preliminary Study because it contains information for only a small subset of ore mining
facilities, due to reporting requirement thresholds. The 2007 TRI database contains discharge
information for only 28 of the 294 estimated ore mines with NPDES permits.
TRI contains facility data for industries in certain North American Industry Classification
System (NAICS) categories. The following NAICS codes are available for the ore mining
industry:
• 212210: Iron ore mining;
• 212234: Copper ore and nickel ore mining;
• 212231: Lead ore and zinc ore mining;
• 212221: Gold ore mining;
• 212222: Silver ore mining;
• 212291: Uranium-radium-vanadium ore mining;
• 212299: All other metal ore mining; and
• 213114: Support activities for metal mining.
The Technical Support Document for the Annual Review of Existing Effluent Guidelines
and Identification of Potential New Point Source Categories contains a thorough discussion of
how EPA uses TRI water discharge information in its annual effluent guidelines planning
process (U.S. EPA, 2009).
2.1.2 Discharge Monitoring Report Data from the Permit Compliance System (PCS) and the
Integrated Compliance Information System for the National Pollutant Discharge
Elimination System (ICIS-NPDES)
DMRs, which facilities are required to submit to EPA or state permitting agencies as a
condition of their NPDES permits, are stored in the PCS and ICIS-NPDES national databases.
EPA began replacing PCS with ICIS-NPDES in 2006. Until the transition is complete, EPA
retrieves certain data from both databases, as was necessary to prepare the Ore Mining
Preliminary Study.
The DMR data used in the Preliminary Ore Mining Study included:
2-2
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Section 2.0 - Data Sources
• Permit limitations;
• Pollutant concentrations and/or load by month, quarter, or other time period; and
• Flow by month, quarter, or other time period.
Similar to the TRI database, however, the PCS and ICIS-NPDES databases were of
limited usefulness for the Ore Mining Preliminary Study because they contain information on
only a subset of ore mines. DMR discharge data were available for only 54 of the 294 ore mines
with NPDES permits.
As summarized in Table 2-2, most discharge data are only available for facilities
classified as major dischargers. Very little data are available for facilities classified as minor
dischargers because states are not required to upload data on minor facilities to the PCS and
ICIS-NPDES databases. Moreover, most permitting authorities classify ore mine discharges as
minor. Permitting authorities consider six factors when determining whether to classify facilities
as major or minor (U.S. EPA, 2006):
• Toxic pollutant potential;
• Discharge flow to stream flow ratio;
• Conventional pollutant loading;
• Public health impact;
• Water quality factors; and
• Proximity to coastal waters.
Table 2-2. Summary of Ore Mining Facilities with Data in EPA's PCS and ICIS/NPDES
Databases
Subpart
A
J
J
J,M
J
J
NA
C
Others b
SIC and Description
1011: Iron Ores
1021: Copper Ores
1031: Lead/Zinc Ores
1041: Gold Ores3
1044: Silver Ores
1061: Ferroalloy Ores (Except Vanadium)
1081: Metal Mining Services
1094: Uranium, Radium, Vanadium Ores
1099: Metal Ores, NEC
Total
Facilities by Type of NPDES Permit
Major
5
11
23
13
1
5
0
7
4
69
Minor
23
15
17
118
24
5
o
3
28
20
253
Total
28
26
40
131
25
10
o
3
35
24
322 c
# of Facilities
with
Discharge
Data
4
5
22
10
1
4
0
4
4
54
Source: EPA's DMRLoads2007 Database.
a - Excludes Mechanical Placer Mining and Suction Dredge Mining; EPA identified 1,869 gold placer and suction
dredge mining operations permitted under a general permit (all discharges classified as minor).
b - Subparts B, D, E, F, G, H, I, K
c - This number differs from the estimated 294 mines with NPDES permits because some mines may have multiple
NPDES permits.
NEC - Not elsewhere classified.
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Section 2.0 - Data Sources
2.1.3 Envirofacts
To augment DMR data available from EPA's annual review databases (PCS, ICIS-
NPDES), EPA reviewed ore mining DMR data available through Envirofacts, an online database
that stores data for various EPA programs (e.g., EPCRA, CWA, RCRA). Envirofacts is available
online at http://www.epa.gov/enviro. It functions as a central repository of permitting
information, including monitoring data for some facilities. Although these data are similar to the
data maintained in EPA's annual review databases, they contain more information for facilities
classified as minor dischargers under the NPDES program. EPA reviewed these data to better
understand discharges from minor facilities permitted under general permits (e.g., general
storm water permits). Montana was the only state in Envirofacts with storm water data; however,
the data for Montana were incomplete. EPA also used Envirofacts to evaluate and augment the
facility list developed during the Ore Mining Preliminary Study.
2.1.4 Enforcement and Compliance History Online (ECHO)
EPA used data from the ECHO database (available online at http://www.epa-
echo.gov/echo) to help develop its ore mining facility list. Similar to the TRI and the PCS/ICIS-
NPDES databases, the ECHO database was of limited usefulness for the Ore Mining Preliminary
Study because it only contains discharge-related information for a subset of ore mines. Using
information from ECHO, PCS, ICIS-NPDES, TRI, and Envirofacts, EPA estimates that there are
294 mines in the US with active NPDES discharge permits.
2.1.5 Total Maximum Daily Load (TMDL) Studies
EPA performed a keyword search of 7,670 TMDL studies to identify active mines that
may be a source of water quality impairment. The TMDL studies are available online at EPA's
Waters website (http://iaspub.epa.gov/waterslO/text_search.tmdl_search), which contains a suite
of water-related databases and analytical tools. The usefulness of the TMDL database was
somewhat limited for Ore Mining Preliminary Study because information on TMDL studies is
incomplete. There may be as many as 4,500 completed studies that have not yet been added to
the TMDL database. Approximately 82 percent of the 42,000 TMDLs approved by EPA since
1995 have not yet been added to the online TMDL database. EPA's use of the TMDL database is
discussed in Chapter 5.
2.1.6 Stormwater Data
The availability of Stormwater data for ore mining operations is very limited due to
minimal monitoring requirements and absence of requirements for states to report mining
Stormwater data to national databases such as the Permit Compliance System.
EPA regional offices and permitting authorities in western states with significant mining
activities were contacted to determine whether they had recent mining Stormwater data of
sufficient quality and representativeness for use in the Ore Mining Preliminary Study. The only
information identified were limited Stormwater monitoring data for certain mines in Arizona
(received from EPA Region 9) and Montana (available through Envirofacts). These data were
not adequate to support any national or regional conclusions about Stormwater discharges from
ore mines (ERG, 2010).
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Section 2.0 - Data Sources
2.2 Data from States and EPA Regional Offices
During the 2009 Annual Review, EPA's Office of Water requested discharge data and
facility lists for ore mining facilities from states and EPA regional offices for areas with
significant mining activities. Table 2-3 lists the responses that EPA received as a result of this
request.
Table 2-3. Summary of Responses to EPA's Information Request
State/EPA
Region
Minnesota
Missouri
New Mexico
Arizona
Region 8
Region 9
Agency
Minnesota Pollution Control Agency
Missouri Department of Natural Resources
New Mexico Environment Department
Arizona Department of Environmental Quality
EPA
EPA
Information Provided
Facility List & Discharge Data
Facility List
Facility List
Facility List
Facility List
Facility List & Discharge Data
Date of
Response
7/22/2009
7/27/2009
7/7/2009
8/4/2009
3/13/2009
7/24/2009
2.3 Non-EPA Data Sources
2.3.1 U.S. Economic Census
The U.S. Economic Census, conducted by the U.S. Department of Commerce, is the
systematic measurement of economic activity in the United States. The census collects
information about the number of manufacturing establishments and the kind, quantity, and value
of goods manufactured. Although the census provides data on the number of establishments by
North American Industry Classification System (NAICS) and U.S. Standard Industrial
Classification (SIC) codes, it does not publish a list of facilities. New facilities might have
started operation since the census was taken (2000), and facilities that were counted in the census
might have been shut down. The census also counts nonproduction facilities such as sales
offices, distribution warehouses, etc., as establishments.
EPA used census data to evaluate and augment its ore mining facility list. EPA compares
the number of mines identified in other data sources to the number summarized by the U.S.
Economic Census in Table 3-2 (U.S. Census, 2005).
2.3.2 USGS Minerals Yearbook and Mineral Commodity Summaries
EPA used information from the 2005 to 2007 USGS Minerals Yearbook and Mineral
Commodity Summaries, which assess the domestic and foreign production of all economic metal
ores, to help develop a list of ore mining facilities.
EPA analyzed information for the following ores:
• Bauxite and Alumina;
• Copper;
• Ferroalloys;
Gold;
• Iron;
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Section 2.0 - Data Sources
• Lead;
• Molybdenum;
• Silver;
• Titanium; and
• Zinc.
2.3.3 Leadville Mine Drainage Tunnel (LMD T) Treatment Plant Information
EPA interviewed staff from the LMDT treatment plant and requested detailed
information on the facility's operations, analytical data characterizing the site's HDS treatment
system, and cost information. The Bureau of Reclamation provided this information to EPA, and
the information was used for the case study discussed in Chapter 8.
EPA interviewed staff from LMDT treatment plant and requested detailed information on
the facility's operations, analytical data characterizing the site's high density sludge treatment
system, and cost information. Chapter 8 discusses information on the LMDT treatment plant,
provided to EPA by the U.S. Bureau of Reclamation.
2.4 Data Sources References
1. U.S. EPA. 2009. Technical Support Document for the Annual Review of Existing
Effluent Guidelines and Identification of Potential New Point Source Categories. EPA-
821-R-09-007. Washington, DC. (October).
2. U.S. Census. U.S. Census Bureau. 2005. U.S. Economic Census. 2002 Economic Census.
Subject Series. Mining. General Summary: 2002. EC02-21SG-1. (October). Available
online at: http://www.census.gov/prod/ec02/ec0221sgl.pdf. EPA-HQ-OW-2006-0771
DCN 05982.
3. U.S. EPA. 2010, Enforcement and Compliance History Online (ECHO). Available online
at: http://www.epa-echo.gov/echo. Date accessed: March 15, 2010.
4. U.S. EPA. 2010, Envirofacts. Available online at: http://www.epa.gov/enviro/ Date
accessed: March 15, 2010.
5. NMED. New Mexico Environment Department. 2009. List of Ore Mining Facilities in
New Mexico. (July 7). DCN 07220.
6. EPA Region 8. 2009. List of Ore Mining Facilities in EPA Region 8. (March 13). DCN
07221.
7. EPA Region 9. 2009. Discharge Data for Select Arizona Ore Mining Facilities. (July 24).
DCN 07225.
8. MFC A. Minnesota Pollution Control Agency. 2009. List of Ore Mining Facilities in
Minnesota. (July 22). DCN 07223.
9. MPCA. Minnesota Pollution Control Agency. 2009. Discharge Data for Select Ore
Mining Facilities in Minnesota. (July 22). DCN 07223.
-------
Section 2.0 - Data Sources
10. ADEQ. Arizona Department of Environmental Quality. 2009. List of Ore Mining
Facilities in Arizona. (March 13). DCN 07226.
11. MDNR. Missouri Department of Natural Resources. List of Ore Mining Facilities in
Missouri. (March 13). DCN 07222.
12. USGS. United States Geological Society. 2010. USGS Website. Available online at:
www.usgs.gov. Date last accessed: April 23, 2010.
13. ERG. 2010. Memo Re: Range of Pollutant Concentrations in Arizona and Montana Ore
Mining Storm water Discharges. April 27, 2010.
2-7
-------
Section 3.0 - Profile of the Ore Mining and Dressing Point Source Category
3.0 PROFILE OF THE ORE MINING AND DRESSING POINT SOURCE CATEGORY
This chapter provides a brief overview of the subcategories of mines covered under 40
CFR Part 440, along with estimates of the number of active mines in each subcategory based on
available data, and a brief summary of mining processes.
3.1 Ore Mining and Dressing Point Source Subcategories
The Ore Mining and Dressing Point Source Category, codified in 40 CFR Part 440, is
divided into the subcategories shown in Table 3-1.
Table 3-1. Ore Mining Category Subcategory Applicability
Sub-
part
A
B
C
D
E
F
G
H
I
Subcategory
Title
Iron Ore
Aluminum Ore
Uranium,
Radium, &
Vanadium Ores
Mercury Ore
Titanium Ores
Tungsten Ore
Nickel Ore
Vanadium Ore
(Mined Alone,
not as By-
product)
Antimony Ore
Related SIC
Code(s)
1011: Iron Ores
1099:
Miscellaneous
Metal Ores, NEC
1094: Uranium-
Radium-Vanadium
Ores
1099:
Miscellaneous
Metal Ores, NEC
1099:
Miscellaneous
Metal Ores, NEC
1061: Ferroalloy
Ores, Except
Vanadium
1061: Ferroalloy
Ores, Except
Vanadium
1094: Uranium-
Radium-Vanadium
Ores
1099:
Miscellaneous
Metal Ores, NEC
Related NAICS
Code(s)
212210: Iron Ores
212299: All Other Metal
Ores
212291: Uranium-
Radium- Vanadium Ores
212299: All Other Metal
Ores
212299: All Other Metal
Ores
212234: Copper and
Nickel Ores
212234: Copper and
Nickel Ores
212291: Uranium-
Radium- Vanadium Ores
212299: All Other Metal
Ore Mining
Subcategory Applicability
Iron Ore Mines and Mills using Physical
or Chemical Separation or Magnetic &
Physical Separation in the Mesabi
Range
Bauxite Mines Producing Aluminum
Ore
Open-Pit or Underground Mines and
Mills using Acid Leach, Alkaline
Leach, or Combined Acid & Alkaline
Leach to Produce Uranium, Radium, &
By-product Vanadium
Open-Pit or Underground Mercury Ore
Mines and Mills using Gravity
Separation or Froth-Flotation
Titanium Ore Mines from Lode
Deposits and Mills using Electrostatic,
Magnetic & Physical Separation, or
Flotation; Dredge Mines and Mills for
Placer Deposits of Rutile, Ilmenite,
Leucoxene, Monazite, Zircon, and
Other Heavy Metals
Tungsten Mines and Mills using Gravity
Separation or Froth-Flotation
Nickel Ore Mines and Mills
Vanadium Ore Mines and Mills
Antimony Ore Mines and Mills
3-1
-------
Section 3.0 - Profile of the Ore Mining and Dressing Point Source Category
Table 3-1. Ore Mining Category Subcategory Applicability
Sub-
part
J
K
M
Subcategory
Title
Copper, Lead,
Zinc, Gold,
Silver, &
Molybdenum
Ores
Platinum Ore
Gold Placer
Mine
Related SIC
Code(s)
1021: Copper Ores
1031: Lead and
Zinc Ores
1041: Gold Ores
1044: Silver Ores
1061: Ferroalloy
Ores, Except
Vanadium
1099:
Miscellaneous
Metal Ores, NEC
1041: Gold Ores
Related NAICS
Code(s)
212234: Copper and
Nickel Ores
2 12231: Lead and Zinc
Ores
212221: Gold Ores
212222: Silver Ores
212299: All Other Metal
Ores
212299: All Other Metal
Ores
2 12221: Gold Ores
Subcategory Applicability
Copper, Lead, Zinc, Gold, Silver, &
Molybdenum Ore Open-Pit or
Underground Mines, except for Placer
Deposits, and Mills using Froth-
Flotation and/or Other Separation
Techniques; Mines and Mills using
Dump, Heap, In-Situ Leach, or Vat-
Leach to Extract Copper from Ores or
Ore Waste Materials; Gold or Silver
Mills using Cyanidation; Except for
Mines and Mills from the Quartz Hill
Molybdenum Project in the Tongass
National Forest, Alaska
Platinum Ore Mines and Mills
Placer Deposit Gold Ore Mines,
Dredges, & Mills using Gravity
Separation
3.2 Estimates of the Number of Active Mines
As discussed in Section 2, the exact number of active mines, and the exact number of
mines with NPDES permits, is unknown. During the Ore Mining Preliminary Study, EPA
developed a facility list using the data sources discussed in Chapter 2. Table 3-2 lists the number
of facilities in each Subcategory, based on the sources discussed in Chapter 2. Figure 3-1
illustrates the distribution of different mine types across the U.S.
EPA developed the facility list starting with the TRI and PCS/ICIS-NPDES databases.
EPA augmented these data with US Census information from the 2005 to 2007 USGS Minerals
Yearbook and Mineral Commodity Summaries, along with facility lists provided by EPA
regional offices and state agencies.
As discussed in Section 2, the exact number of active mines, and the exact number of
mines with NPDES permits, is unknown. During the Ore Mining Preliminary Study, EPA
developed a facility list using the data sources discussed in Chapter 2. Table 3-2 lists the number
of facilities in each Subcategory, based on the sources discussed in Chapter 2. Figure 3-1
illustrates the distribution of different mine types across the U.S.
A detailed facility list is contained in DCN 07228. However, EPA considers each of the
data sources used to compile the list to be incomplete. EPA developed the facility list starting
with the TRI and PCS/ICIS-NPDES databases. EPA attempted to correlate facilities between
data sources using available information, but some facilities may be double-counted due to
facility name differences between data sources. The "Estimated Total Number of Facilities" in
Table 3-2 is different than the numbers from each data source for some subcategories because no
single data source contained all of the known facilities. EPA augmented data from TRI and
PCS/ICIS-NPDES with US Census information and from the 2005 to 2007 USGS Minerals
-------
Section 3.0 - Profile of the Ore Mining and Dressing Point Source Category
Yearbook and Mineral Commodity Summaries, along with facility lists provided by EPA
regional offices and state agencies.
Table 3-2. Estimated Number of Facilities in the Ore Mining Category
Subpart(of40CFR440)
A: Iron Ore
C: Uranium, Radium, and
Vanadium
J: Silver
J: Lead/Zinc
J: Gold
J: Copper and Nickel Ore d
J: Molybdenum
E: Titanium Ore
F: Tungsten Ore
I: Antimony Ore
K: Platinum Ore
D: Mercury Ore
B : Aluminum Ore
Total (Excluding Placer
Mines)
M: Gold Placer Mines
2002 U.S.
Economic
Census
24
17
11
22
180
33
39
326
0J
Number of
Facilities
Reporting to
TRIa
Oc
Oc
3
19
43
25
4
1
0
0
1
0
0
96
0
Number of
Facilities with
Discharges in
EPA's DMR
Pollutant Loading
Tool
27
24
23
32
113
54
8
6
0
0
1
0
2
290
1679
Estimated Total
Number of Facilities b
32
24
25
37
143
59
9e
7
lf
lg
1
Oh
2
345'
1679
a - All facilities reporting to TRI (including facilities without discharges).
b - EPA estimated the total number of facilities in each database by compiling USGS , Census, Envirofacts, TRI,
and DMR data into one list (see DCN 07228). EPA identified situations where a facility was in only one databases
or in all databases.
c - Facilities mining iron, uranium, radium, or vanadium ores are not required to report to TRI.
d - Many U.S. mines co-produce nickel and copper. For all of the mines reporting the NAICS code for copper and
nickel ores that EPA reviewed in detail, copper is the principal product. EPA has not identified any U.S. mines for
which nickel is the principal product.
e - Assumes that all facilities reporting SIC 1061 (Ferroalloy except vanadium) are molybdenum mines.
f - Although one mine is listed in the USGS Minerals Yearbook (the Andrew Mine in California), EPA's databases
have no information for this mine.
g - Although one mine is listed in the USGS Minerals Yearbook (the Fencemaker Mine in Nevada), EPA's
databases have no information for this mine.
h - Based on the USGS Minerals Yearbook, there are no mines in the U.S. producing this metal as their principal
product.
i - Total number of facilities includes some mines for which the applicable subpart is unknown.
j - The Economic Census does not distinguish between placer mines and other types of gold mines.
ND - No data.
3-3
-------
Section 3.0 - Profile of the Ore Mining and Dressing Point Source Category
P—~- S i, A-; v
/ T\ • « ^_^
Legend
j State Boundaries • Iran •* Silver
Copper • Lead/Zinc ? Unknovwi
Ferroalloy (except vanadium) « Miscellaneous Ores, NEC + Uranium/Radium/vanadium
Gold i Molybdenum
0 250 500 1,000 1,500 2,000
• • ^^^» ^^^» Mi Ic;
Figure 3-1. Ore Mines in the U.S. by Type (Based on Primary Commodity)
3-4
-------
Section 3.0 - Profile of the Ore Mining and Dressing Point Source Category
3.3 Ore Mining Processes
EPA's Technical Resource Document: Extraction and Beneficiation of Ores and
Minerals presents a detailed discussion of the processes used in some of the major ore mining
subcategories. This document consists of seven volumes, discussing the following types of ore
extraction and processing (EPA Publication Number in parenthesis):
Volume 1: Lead-Zinc (EPA 530-R-94-011);
Volume 2: Gold (EPA 530-R-94-013);
Volume 3: Iron (EPA 530-R-94-030);
Volume 4: Copper (EPA 530-R-94-031);
Volume 5: Uranium (EPA 530-R-94-032);
Volume 6: Gold Placer (EPA 530-R-94-035); and
• Volume 7: Phosphate and Molybdenite (EPA 530-R-94-034).
Other useful descriptions of ore mining processes are contained in Site Visit Report:
Arizona Copper Mines, prepared as part of the Ore Mining Preliminary Study.
3.4 Profile of the Ore Mining Category References
1. ERG. 2010. Site Visit Report: Arizona Copper Mines. (March). Chantilly, VA. DCN
07219.
3-5
-------
Section 4.0 - Regulatory Framework for Ore Mining Discharges
4.0 REGULATORY FRAMEWORK FOR ORE MINING DISCHARGES
Under Section 304(b) of the Clean Water Act (CWA), EPA first promulgated Ore Mining
and Dressing Point Source Category Effluent Limitation Guidelines (ELGs), (40 CFR Part 440)
on December 3, 1982, (47 FR 54609) to set national technology-based pollutant limits for
wastewater discharges from ore mining and dressing facilities. 40 CFR Part 440 consists of 12
subcategories, as outlined in Table 3-1 (U.S. EPA, 1982; U.S. EPA, 1988). Discharges from
mining and dressing operations must meet best available technology/best practicable technology
(BAT/BPT) limits for metals such as arsenic, cadmium, copper, lead, mercury, nickel, and zinc;
as well as meeting BPT limits for total suspended solids and pH. Certain facilities in some
subcategories must also meet the New Source Performance Standards (NSPS) of no discharge
except in areas where net precipitation (precipitation minus evaporation and infiltration) is
greater than zero. Storm exemptions are provided in some cases for all subcategories. Tables A-l
and A-2 in Appendix A summarize the numeric limits for each subpart.
4.1 Overview of NPDES Permitting
Under Section 402 of the Clean Water Act (CWA), EPA and authorized states regulate
direct point source discharges to waters of the United States by issuing National Pollutant
Discharge Elimination System (NPDES) (40 CFR 122.44) permits to facilities. A point source is
defined in Section 502 of the CWA as a confined and discrete conveyance, natural or man-made,
such as a pipe, ditch, or outfall from which a pollutant may be discharged. For mining facilities,
point source discharge sources include mine drainage and process wastewater; and may or may
not include stormwater runoff (U.S. EPA, 1996).
EPA has authorized state agencies to administer the NPDES program in all but New
Mexico, Idaho, Massachusetts, New Hampshire, and Washington D.C. For these States, some
Tribal Lands, some federal facilities, and U.S. Territories, EPA Regional offices retain NPDES
permitting authority.
NPDES permits are issued to control either industrial wastewater or stormwater. There
are three types of NPDES permits (U.S. EPA, 1996):
• Individual. Individual NPDES permits set wastewater discharge limits and
conditions for single facilities on a case-by-case basis. NPDES permit writers
consider a facility's production processes, the characteristics of the discharge, and
the quality of the receiving water quality in determining permit limits and
conditions.
• General. A general permit covers multiple facilities with similar production
processes and pollutant discharges within a specific geographical area. Some
facilities with individual permits for process water discharges may also be
covered under general stormwater permits.
• Watershed. Watershed permits are relatively new and are being implemented for
certain industries by a subset of states. Similar to a general permit, watershed
permits cover multiple facilities within a watershed and account for the effects of
multiple pollutant discharges, habitat conditions, stream flow, ecology, and other
factors such as any Total Maximum Daily Load (TMDL) developed for
-------
Section 4.0 - Regulatory Framework for Ore Mining Discharges
waterbodies in the watershed. No ore mines in 2010 are known to be covered
under watershed permits.
4.2 NPDES Permitting of Process Water and Stormwater from Ore Mines
In the August 1998 Federal Register Notice (63 FR 42533-42548), EPA clarified the
Stormwater applicability of 40 CFR Part 440 in response to litigation with the National Mining
Association: "runoff from waste rock and overburden piles is not subject to ELGs unless it
naturally drains (or is intentionally diverted) to a point source and combines with 'mine drainage'
that is otherwise subject to the ELGs."3 Thus process water is covered under individual or
general NPDES industrial wastewater permits based on 40 CFR Part 440. Some Stormwater
runoff at mines may be controlled under individual or general NPDES industrial wastewater
permits based on 40 CFR Part 440, and other Stormwater runoff at mines may be controlled
under individual or general NPDES Stormwater permits.
In jurisdictions that EPA has not authorized to implement the NPDES program,
Stormwater discharges are subject to Sector G of EPA's Multisector General Permit for Industrial
Activities (MSGP) developed to implement Phase I Stormwater Regulations (40 CFR Part
122.26). Authorized states have developed their own general Stormwater permits for mining
discharges that conform to the MSGP.
Figure 4-1 illustrates the process used to determine the regulatory classification of
discharges from ore mining operations, which depends on whether a discharge is process water
or Stormwater, and whether the water is managed by commingling with other wastewaters or
individually conveyed to discharge point.
EPA's MSGP, and some state general Stormwater permits, include requirements to
conduct benchmark monitoring and develop Best Management Practices (BMPs). Stormwater
pollution prevention plans are also required, but numeric discharge limits are not set, nor are
Stormwater containment and treatment requirements established. The MSGP benchmark
monitoring concentrations are used as action levels to determine whether existing BMPs are
sufficient. If benchmark concentrations are exceeded, the facility must augment existing BMPs
and continue sampling Stormwater. However, if pollutant concentrations are consistently below
benchmark concentrations, the facility may cease Stormwater sampling. The MSGP does require
that storm water discharges comply with state water quality standards, but specific numeric
limits are not included in the permit.
Most state Stormwater general permits are less restrictive than the federal MSGP because
they require less or no benchmark monitoring, which is used to assess the effectiveness of BMPs.
Four states require no benchmark monitoring for metals concentrations, eight states require less
frequent sampling than specified by the Federal MSGP; and two states require no routine
sampling at all. Only one state, Washington, requires more stringent Stormwater monitoring than
the federal MSGP.
3 Table G-4 of the MSGP lists the wastewaters from mining activities covered by Part 440 versus the MSGP, as
specified in an October 2000 Federal Register Notice: runoff from waste rock and overburden piles is not subject to
effluent guidelines unless it naturally drains (or is intentionally diverted) to a point source and combines with "mine
drainage" that is otherwise subject to the effluent limitation guidelines (65 FR 64774, October 30, 2000).
-------
Section 4.0 - Regulatory Framework for Ore Mining Discharges
Yes
Do discharges from waste rock 01
overburden piles combine with
"mine drainage"?
Total Discharge, including
storm water runoff, subject to
40 CFR 440
Yes
Is there a dry weather point
source discharge from the pile?
No
Individual permit required to
discharge (include BPJ
technology-based limits)
Coverage tentatively allowed
under multi-sector general
storm water permit
1. Implement BMPs
2. Initial screen
3. Twice yearly monitoring for metal
Are pollutants discharged at
levels well below benchmark
threshold values?
Yes
Would the discharge cause or
contribute to a water quality
standards violation?
Individual permit required to
discharge (include water
quality-based limits)
Yes
No
Coverage
under an
individual
NPDES permit
No
_
Individual permit required
to discharge (include BPJ
technology-based limits)
Yes
Discharges solely composed
of storm water covered by
multi-sector general storm
water permit
Figure 4-1. Example of Discharge Classification Depending on Wastewater Source and
Management (U.S. EPA, 2003)
4-3
-------
Section 4.0 - Regulatory Framework for Ore Mining Discharges
Table 4-1 compares MSGP benchmark monitoring requirements with those in stormwater
general permits issued by authorized states with significant ore mining operations.
4.3 Distinction Between Technology-Based Permit Limits and Water Quality-Based
Permit Limits
If a facility applies for an individual NPDES permit, the permit writer is required to first
derive facility-specific Technology-Based Effluent Limits (TBELs) based on 40 CFR Part 440.
The permit writer then derives discharge limits for the facility that are protective of state water
quality standards, known as Water Quality-Based Effluent Limits (WQBELs). The permit writer
is required to compare the TBELs with the WQBELS, and apply the more stringent of the two
limits in the permit in order to ensure attainment of the state water quality standards in the
receiving waterbody. If a state has adopted a Total Maximum Daily Load (TMDL) for the
receiving waterbody, then the permit writer must also determine the water quality-based waste
load allocation for the discharge.
4.4 Ore Mining Regulatory Framework References
1. U.S. EPA. 1982. Development Document for Effluent Guidelines and Standards for the
Ore Mining and Dressing Point Source Category. EPA-440/1-82-061. Washington, DC.
2. U.S. EPA. 1988. Development Document for Effluent Limitations and Guidelines for
New Source Performance Standards for the Ore Mining and Dressing Point Source
Category Gold Placer Mine Subcategory. EPA-440/1-88-061. Washington, DC.
3. U.S. EPA. 1996. NPDES Permit Writers' Manual. Washington, D. C.
4. U.S. EPA. 2003. EPA and Hardrock Mining: A Source Book for Industry in the
Northwest and Alaska. Seattle, WA.
5. U. S. EPA, 2006a. Technical Support Document for the 2006 Effluent Guidelines
Program Plan. Washington, D.C.
6. U. S. EPA, 2006a. Technical Support Document for the 2006 Effluent Guidelines
Program Plan. Washington, D.C.
4-4
-------
Section 4.0 - Regulatory Framework for Ore Mining Discharges
Table 4-1. Comparison of Monitoring Requirements for Western States and Federal General Stormwater Permits
Permit a
Washington
2008 Federal
MSGP (covers
Idaho and New
Mexico °)
California
Montana
Arizona d
Utah
Nevada
Wyoming
South Dakota
Colorado
Monitoring Requirements
Permittee must monitor discharges four times per year until concentrations below benchmarks
are measured for eight quarters.
Permittee must monitor discharges four times per year in the first year of permit coverage. If
pollutant concentrations exceed benchmark values, then the permittee must implement
additional BMPs to remedy the situation and continue to monitor four times per year until
measured concentrations are below benchmark values.
Permittee must monitor discharges three times per year.
Permittee must monitor discharges at least twice per year until all concentrations are below
benchmarks for three consecutive sampling events.
Permittee must monitor at least once during the first year of coverage. If pollutant
concentrations exceed benchmark values, then permittee must implement additional BMPs to
remedy the situation and must continue to monitor twice per year until measured
concentrations are below benchmark values.
Copper mining and dressing facilities must monitor their discharges four times per year for
COD, TSS, and nitrate plus nitrite nitrogen during years 2 and 4 of permit coverage. No
requirements for other types of mines.
Permittee must monitor discharges once per year; alternatively, the permittee may submit a
statement that these discharges will not cause exceedances of applicable WQS.
Permittee must monitor discharges once per year.
Except for coal pile runoff, monitoring is not required on a routine basis. e
Monitoring is not required on a routine basis. e
Analytes to be Monitored
1
V
'
'
'
s
I
'
Turbidity
'
n
'
s
'
'
Hardness
'
'
.D
"3
t5
'
'
'
Sulfates
'
0
O
u
'
'
s
Nitrogen
(N03+N02)
'
'
V
Source: State general permits.
a - Ranked by amount of monitoring required.
b - Facilities are required to monitor for a variety of metals. Monitored metals vary by state and - in some states - mine type.
c - Facilities in Alaska are covered by the 2008 Federal MSGP until its state general permit is published.
d - Arizona continued the 2000 Federal MSGP until the state general permit is published.
e - State may require sampling if noncompliance with Stormwater Pollution Prevention Plan is suspected or to measure the effectiveness of BMPs.
4-5
-------
Section 5.0 - Review of TMDL Studies to Determine the Extent to Which Ore Mines May Be a Cause of
Water Quality Impairments
5.0 REVIEW OF TMDL STUDIES TO DETERMINE THE EXTENT TO WHICH ORE MINES MAY
BE A CAUSE OF WATER QUALITY IMPAIRMENTS
Under CWA Section 303(d) NPDES authorized states, territories, and tribes are required
to develop lists of impaired waters that do not meet water quality standards. Permitting
authorities are required to prioritize impaired waters and develop Total Maximum Daily Loads
(TMDL) to restore their designated uses to support drinking water supply, aquatic life, or
recreation. The TMDL study, which permitting authorities submit to EPA for approval, identifies
sources of impairment and specifies the maximum amount of both point source and nonpoint
source pollutants that can be discharged. Since 1995, EPA has approved approximately 42,000
TMDLs.
EPA reviewed the 7,760 TMDL studies that are stored electronically and available for
keyword searching on EPA's Waters4 website. The representativeness of these studies is
somewhat limited, given that they comprise only 18 percent of the approved TMDLs.
Nevertheless, in the absence of more complete information, they serve as an indicator of ore
mines as potential process water and stormwater sources of water quality impairment.
EPA's review of TMDL studies identified many instances where past ore mining
operations impaired surface water quality. However, EPA found no TMDL studies that identified
active ore mines as sources of water quality impairments.
5.1 EPA's Approach to Screening TMDL Studies
EPA systematically searched all of the 7,670 electronically available TMDL studies for
the terms "mine" or "mining." The search identified 1,668 TMDL studies that included
references to ore mining, as well as to other types of mining such as coal mining and gravel
mining. EPA then further screened the subset of TMDL studies with mining references to
identify those that contained information relevant to ore mining facilities. This was done by
limiting the search to TMDL studies in states with major ore mining activity (Alaska, Arizona,
California, Colorado, Montana, New Mexico, Nevada, South Dakota, Utah, and Washington),
which narrowed the number of TMDL studies to 158. EPA then performed the following steps:
1. EPA determined whether or not the mining operations discussed in the TMDL
studies were ore mining operations. Studies that did not provide any detail on the
type of mining present in the watershed were removed from further analysis,
which reduced the number of studies for further review from 158 to 42.
2. EPA determined whether the studies identified abandoned or closed mines. EPA
recorded this information, but did not use it to screen documents for further
review.
3. EPA determined whether the document identified large-scale active mines, which
excluded mining activities such as small-scale placer mining and recreational gold
panning. Removing documents that did not specifically describe large-scale,
active mines reduced the number of documents for further review from 42 to 9.
4 Available online at http://iaspub.epa.gov/waterslO/text_search.tmdl_search_form. Accessed on January 22nd,
2009.
-------
Section 5.0 - Review of TMDL Studies to Determine the Extent to Which Ore Mines May Be a Cause of
Water Quality Impairments
4. EPA performed a text search using the terms "waste rock" and "tailing" to
identify documents that discuss water quality impacts from waste rock and
tailings piles, but did not use this step to screen documents for further review.
5. EPA verified that the remaining TMDLs studies listed ore mining as a source of
impairment. In cases where it was not clear that mining was a source of
impairment, EPA removed the study from further analysis, which reduced the
number of documents for further review from 9 to 7.
5.2 Results of Screening the TMDL Studies
EPA identified seven TMDL studies that described impacts from mining operations that
were active or recently active at the time the studies were written. Table 5-1 summarizes these
studies. Ore mining operations will commonly close and re-open periodically according to the
fluctuating prices of the metals they produce. Few mines are operated continuously over spans of
time long enough to identify them as sources of impairment while they are still active.
Consequently, EPA included TMDL studies that contained discussion of recently closed mines.
EPA reviewed in detail the relevant information in these studies. Although mines were listed
among the sources within impaired watersheds, none of the TMDL documents definitively stated
that impairments resulted from any active mines.
For additional detail on the seven TMDL studies listed in Table 5-1, see DCN 06916.
5.3 Ore Mining Water Quality Impact References
1. EPA, 2001. The National Costs of Implementing TMDLs. Washington, D.C.
2. ADEQ, 1999. Total Maximum Daily Load And Implementation Plan For Mercury Pena
Blanca Lake, Arizona.
3. NMED, 2006. Total Maximum Daily Load for the Red River Watershed: Rio Grande
River to Headwaters.
4. ADEQ, 2005. French Gulch TMDLs for Cadmium, Copper, and Zinc: Headwaters to
Hassayampa River.
5. EPA, 2001. Trinity River Total Maximum Daily Load for Sediment.
6. EPA, 2001. Total Maximum Daily Load for Copper in Pinto Creek, Arizona.
1. EPA, 2003. Bryant Creek: Total Maximum Daily Loads - Arsenic, Iron, Nickel,
Turbidity, and Total Suspended Solids.
8. Washington State Department of Ecology, 2003. Colville River Watershed Bacteria Total
Maximum Daily Load. Olympia, Washington.
5-2
-------
Section 5.0 - Review of TMDL Studies to Determine the Extent to Which Ore Mines May Be a Cause of Water Quality Impairments
Table 5-1. TMDL Studies with Information on Active and Recently Closed Ore Mines
TMDL Study
Pinto Creek,
Pinto Creek, AZ
French Gulch,
Hassayampa River, AZ
Pena Blanca,
Pena Blanca Lake, AZ
Red River,
Rio Grande to
Headwaters. New
Mexico
Bryant Creek,
Doud Springs, NV
Lower Similkameen
River,
Oroville, WA
Trinity River,
Trinity River Basin, CA
Parameters
Associated with
Impairment
Cu
Cd, Cu, Zn
Hg
Al, turbidity,
and sediment
As, Cu, Fe, Ni,
temperature,
turbidity, TSS
As
Sediment
Active and Recently Closed
Mines b
• Gibson Mine (closed)
• BHP Pinto Creek Mine (active)
• Carlota Copper Project (active)
• Zonia Mine (closed)
• St. Patrick Mine (closed)
• Molycorp Questa Mine (active)
• Leviathan Mine (closed)
• Similco Mine (active)
• Dankoe Mine (active)
• Corona Nickel Plate Mine
(active)
• Cadorado Mine (active)
• (All in Canada)
• Deiner Mine (closed)
• La Grange (closed)
Summary of Data Available
Appendix A (data and figures) is not included
in the available TMDL report; some data are
provided in the text of the report.
Document includes extensive in-stream
monitoring data for metals and load estimates
for all stream segments.
Study provides concentration data from
sediment and fish tissue samples and some
concentration data from water column samples
Document includes in-stream monitoring data
for aluminum, benthic macroinvertebrates,
stream flow, turbidity, and TSS; it does not
provide data for any mine sites.
Document includes statistical summary of
stream flow, arsenic, iron, turbidity, and TSS
measurements in creek. No data are provided
for mine sites.
Document includes in-stream monitoring data
for arsenic. No data are provided for mine
sites.
Study estimates sediment loads from major
sources.
Additional Comments
The partial data that were available
did not clearly identify documented
surface water impacts from the active
mines.
No data documented that the Zonia
Mine discharges led to stream
impairment.
The TMDL study identified other past
mining projects and current
exploratory projects, but it does not
provide information on their relative
potential mercury loads.
None.
Although mining impacts are
referenced throughout the TMDL
document, the study describes only
the Leviathan Mine.
The TMDL study acknowledges that
active mining occurs in the U.S.
portion of the Similkameen
watershed, but it does not specifically
mention any mine sites in the U.S.
None.
a - Listed in order of probable relevance to the Ore Mining Effluent Guidelines.
b - Mine status in parenthesis. "Closed" means both inactive and permanently closed.
TSS - Total Suspended Solids.
5-3
-------
Section 5.0 - Review of TMDL Studies to Determine the Extent to Which Ore Mines May Be a Cause of
Water Quality Impairments
9. Washington State Department of Ecology, 2004. Issaquah Creek Basin Water Cleanup
Plan for Fecal Coliform Bacteria: Total Maximum Daily Load. 2003. Bellevue,
Washington.
10. Washington State Department of Ecology, 2004. Lower Similkameen River Arsenic Total
Maximum Daily Load. Olympia, Washington.
5-4
-------
Section 6.0 - Process Water Discharges
6.0 PROCESS WATER DISCHARGES
Table 6-1 summarizes annual discharge estimates for ore mining facilities based on
available 2007 data. Table 6-1 presents data just for 2007 because that was the most recent year
with data available when EPA initiated the Ore Mining Preliminary Study. EPA checked the
quality of the data by contacting facilities with high discharge concentration values that appeared
to be outliers inconsistent with other data. EPA found that reporting errors had occurred in
several cases and that actual discharge concentration values were significantly lower. EPA made
adjustments to data based on information provided by facilities.
The data in Table 6-1 were taken from EVA'sDMRLoads2007 Database, which contains
discharge data primarily for "major" facilities. Data for facilities classified as "minor" are not
required to be reported at the national level, although some states report these data voluntarily.
Permitting authorities classify facilities as either major or minor based on an assessment of six
criteria (U.S. EPA, 2010):
• Toxic pollutant potential;
• Discharge flow to stream flow ratio;
• Conventional pollutant loading;
• Public health impact;
• Water quality factors; and
• Proximity to coastal waters.
Consequently, Table 6-1 only contains information for the 54 largest major ore mining
facilities that reported discharge information for 2007. An estimated 240 minor facilities are not
included in Table 6-1.
Table 6-1. 2007 Discharge Summary for the Ore Mining Category
Rank
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
NPID
CO0000248
MN0055301
MOO 100226
AK0053341
UT0000051
ID0000027
MO0000086
MO0001856
MO0001848
SD0026883
CA0081876
NY0001791
SD0025852
AR0000582
MO0100218
AK0043206
Name
Climax Mine
Northshore Mining/Silver Bay
Doe Run Resources Co
Teck-Pogo Inc
Kennecott Copper Co
U.S. Silver Corporation
Doe Run Company
Doe Run Resources Co
Doe Run Resources Corp
LAC Minerals
Mammoth,Sutro,Keystone Et Al
Balmat Mines & Mill
Wharf Resources (USA)
Alcoa Arkansas Remediation
Doe Run Company
Kennecott Greens Creek Mining
Location
Summit County, CO
Silver Bay, MN
Viburnum, MO
Delta Junction, AK
Magna, UT
Wallace, ID
Viburnum, MO
Viburnum, MO
Viburnum, MO
Central City, SD
Redding, CA
Balmat, NY
Lead, SD
Bauxite, AR
Bunker, MO
Juneau, AK
Total
Pounds
Released a
225,030,925
4,364,800
17,001,883
3,776,218
142,677,370
21,995
133,893
1,821,703
2,412,669
4,972,369
5,836
15,969,640
3,071,229
132,152
48,310
349,176
TWPE
50,502
40,981
28,207
17,714
11,517
9,072
6,920
5,022
3,121
2,004
1,854
1,351
1,227
924
916
396
6-1
-------
Section 6.0 - Process Water Discharges
Table 6-1. 2007 Discharge Summary for the Ore Mining Category
Rank
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
NPID
MI0000094
TN0001732
MI0038369
CO0024562
NM0022306
UT0022403
CO0041467
SD0026905
CO0038334
TN0061468
MN0046981
MO0001872
AZ0020401
TN0001759
AK0050571
CO0035394
AK0038652
TN0001741
TN0027677
ID0025402
ID0026468
CO0038954
WA0025721
FL0000051
NM0020532
FL0040274
TN0060127
FL0000035
TN0057029
NM0020435
NM0028100
NM0028169
NV0023345
SD0000043
MT0000191
ID0000175
TN0004227
TN0029360
Name
Empire Iron Mining Partnership
East Tennessee Zinc Co. LLC
Tilden Mining Company L.C.
Carton Tunnel Portal Site
Chevron Mining Inc.
Jordanelle Ssd
Henderson Mine, Urad Minesite
Golden Reward Mining Co.
London Water Tunnel
East TN Zinc Co., Lie
Northshore Mining Co; Cliffs MN
Cominco American Inc
Bhp Pinto Valley Operations
East Tennessee Zinc Co., LLC
Coeur Alaska Inc
Mt. Emmons/Keystone Mine
Teck Cominco Alaska Inc
East Tennessee Zinc Co., LLC
East Tennessee Zinc Co., LLC
Thompson Creek Mining
Hecla Mining Company
Platoro Joint Venture
Dawn Mining Company
Bradford County
Rio Algom Mining, LLC
E.I. Dupont De Nemour-Maxville
O-N Minerals(Luttrell) Co.
State Route 125
Mossy Creek Mining, LLC
Chino Mines Company
Rio Grande Resources Corp.
Mineral Energy and Technology
Esmeralda Project Gold Mine
Sd Science And Technology
Montana Resources
Hecla Mining Company
Mossy Creek Mining, LLC
Mid-Tennessee Zinc Corporation
Location
Palmer, MI
Jefferson City, TN
Ishpeming, MI
Teller County, CO
Questa, NM
Park City, UT
Clear Creek, CO
Lead, SD
Park County, CO
Jefferson City, TN
Babbitt, MN
Bixby, MO
Miami, AZ
Mascot, TN
Juneau, AK
Gunnison County, CO
Kotzebue, AK
New Market, TN
Jefferson County, TN
Challis, ID
Stanley, ID
Conejos County, CO
Wellpinit, WA
Bradford County, FL
Mckinley County, NM
Starke, FL
Thorn Hill, TN
Clay County, FL
New Market, TN
Hurley, NM
Cibola County, NM
Sarquez, NM
Hawthorne, NV
Lead, SD
Butte, MT
Mullan, ID
Elmwood, TN
Gordonsville, TN
Total
Pounds
Released a
14,241,519
77,583
13,320,379
40,828
5,670
11,017
93,143
4,339,129
1,309
9,530
2,140,070
5,676
7,079,818
13,709
1,154,488
1,864,673
1,585,789
7,114
4,487
1,064,984
653,375
196,805
1,035,549
28,892
6,726
18,382
5,058
2,659
179
0
0
0
0
0
0
0
37,155
0
TWPE
394
373
315
294
252
186
142
131
95
86
73
71
51
50
36
29
28
22
17
16
16
14
13
10
7
o
5
2
1
0
0
0
0
0
0
0
0
0
0
Source: EPA'sDMRLoads2007 Database.
a - Facilities with zero total pounds released had no discharges in 2007.
6.1 Process Water Discharges References
1. EPA, 2010. NPDES Permit Writers' Manual. Washington, D. C.
6-2
-------
Section 7.0 - Stormwater Analysis
7.0 STORMWATER ANALYSIS
As noted in Section 2, EPA was only able to obtain stormwater discharge data for a
subset of ore mines in Arizona and Montana, which EPA reviewed to assess the range of
pollutant concentrations in stormwater from ore mining operations. The Arizona and Montana
stormwater data, however, were not adequately representative to support any national or regional
conclusions about stormwater discharges from ore mines (ERG, 2010a).
EPA Region 9 provided stormwater monitoring data for eight Arizona ore mines. EPA
also identified a limited amount of stormwater monitoring data available through Envirofacts
(see Section 4.1.2.2) for 11 ore mines in Montana. EPA also received discharge monitoring
reports (DMR) for 17 Minnesota ore mines, along with monitoring data submitted with Form 2c
of the NPDES Permit Application for 6 of these 17 facilities, from the Minnesota Pollution
Control Agency. However, EPA determined that all but one of the Minnesota stormwater
discharges covered by the Minnesota DMRs were commingled with process water discharges, so
that no discharge data were available for segregated stormwater discharges. Consequently, EPA
was not able to use the Minnesota data to characterize the range of pollutant concentrations in
Minnesota ore mining stormwater discharges.
As discussed in Section 4, and reflected in Table 4-2, the availability of stormwater data
for ore mining operations is very limited due to minimal benchmark monitoring requirements.
Moreover, many states do not maintain electronic copies of stormwater data, and there are no
requirements for states to report mining stormwater data to national databases such as the Permit
Compliance System.
Based on the information presented in Appendix B, the following states have at least ten
permitted discharges regulated by general stormwater permits (number of permitted discharges
in parentheses):
• Arizona (31);
Alaska (25);
• Montana (15);
• Wyoming (12);
Idaho (13);
California (11);
• Colorado (10); and
• Nevada (10).
In addition to searching for available stormwater data, EPA also observed stormwater
controls at three Arizona copper mines during site visits in September 2009, to better understand
stormwater management at ore mines. Detailed information on the facilities that EPA visited is
included in the site visit report (ERG, 201 Ob).
7.1 Quality Procedures Used to Create Analysis Spreadsheets
EPA entered stormwater monitoring data into a spreadsheet database and calculated
statistical parameters (e.g., median, maximum) for parameters regulated by the Ore Mining
Effluent Guidelines. Data were excluded from analysis in the following cases:
-------
Section 7.0 - Stormwater Analysis
• Where more than one measurement was made for a parameter at one outfall
during a reporting period, EPA used the maximum value only (the reported
quantity is a daily maximum) and excluded all other values.
• EPA excluded data points where the DMR indicated no discharge.
• EPA excluded measured pollutant concentrations where QA issues (e.g., holding
time exceedances, insufficient sample volume) were indicated in the DMR.
For metals, EPA considered "total" and "total recoverable" measurements to be
equivalent (EPA, 1998).
For the purposes of the statistical analyses, EPA assumed that a pollutant's concentration
was zero when it was reported "not detected" or less than the detection limit. This approach
likely underestimates average pollutant concentrations, but it does not affect any other elements
of the statistical analysis.
EPA verified that all data to be used were for stormwater discharges only using the
following procedures:
• For the Arizona data, EPA verified that each of the permit IDs under which the
monitoring data were collected and reported were general stormwater permit IDs.
• For the Minnesota data, EPA reviewed the outfall descriptions provided in the
NPDES permit applications. EPA did not analyze these data because none of the
outfalls with monitoring data were purely stormwater (based on outfall
descriptions).
• For the Montana data, EPA verified that each of the outfalls was classified with
an "R" code in Envirofacts, indicating that it was a stormwater outfall.
EPA also compared stormwater pollutant concentrations to daily maximum limits
specified in Subpart J of the Ore Mining Effluent Guidelines (Copper, Lead, Zinc, Gold, Silver,
and Molybdenum Ores Subcategory) 5 and benchmark concentrations specified in the 2008
Multi-Sector General Permit (MSGP) for industrial stormwater discharges (EPA, 2008)6.
7.2 Stormwater Monitoring Data for Arizona
EPA received hardcopies of DMRs from the Region 9 Office for eight copper mines.
These DMRs include daily maximum values for each parameter measured, but do not include
monthly average values. In addition to pollutant concentrations, the DMRs include estimated
cumulative flow, data qualifiers for quality control issues (e.g., holding time exceedances,
insufficient sample volume), and a check box to indicate periods when no discharge occurred.
Table 7-1 summarizes the facilities and time periods covered by these data, as well as the
parameters monitored at each facility.
5 The Ore Mining Effluent Guidelines do not apply to the discharges discussed in this chapter. They are used here
for comparison.
6 EPA did not compare metals concentrations to MSGP benchmark concentrations (which are dependent on the
hardness of the receiving water), because hardness measurements for the receiving waters were unavailable.
-------
Section 7.0 - Stormwater Analysis
Table 7-1. Stormwater Monitoring Data Available for Arizona Ore Mines
Facility Name
Copper Cities
Florence
Pinto Valley
Morenci
Sierrita
San Manuel
Mine
Silver Bell
Superior
Permit ID
AZR05A798
AZR05A795
AZR05A796
AZR05A711
AZR05A550
AZR05B412
AZR05A789
AZR05A800
Mine Type
Copper
Copper
Copper
Copper
Copper
Copper
Copper
Copper
Monitoring
Period a
January 1999 -
August 1999
April 1999 -
September 1999
January 1999 -
September 1999
January 1999 -
September 1999
January 2000 -
December 2000
July 2001 -
September 2001
January 1999 -
March 2002
January 1999 -
December 2000
Monitored Parameters
tt
j
j
,
,
J
,
J
,
1
J
,
J
,
J
,
n
,
j
,
j
,
in
H
j
j
,
,
j
,
j
,
Q
o
u
J
J
,
,
,
J
,
Hardness
x
j
,
^
,
Turbidity
j
j
,
j
,
o"
Z Z
j
j
,
,
,
J
,
a - In some cases, monitoring data are not continuous for the period specified (some periods without data).
EPA entered the DMR data into a spreadsheet database, and used the methods to process
and analyze the data described in Section 7.1. Table 7-2 summarizes the Arizona Stormwater data
and compares them to the limits and benchmarks.
Copper, zinc, and TSS all exceed the numerical limits from the Ore Mining Effluent
Guidelines in the majority of the Stormwater data for Arizona.
All 35 TSS samples exceed the daily maximum limit set by the Ore Mining Effluent
Guidelines (30 mg/L)7, and 32 of the 35 samples exceed the MSGP benchmark value (100
mg/L). The average and median TSS concentrations in the Arizona Stormwater data are 3,200
and 2,000 mg/L, respectively.
The average and median concentrations for copper and zinc exceed the daily maximum
limits set by the Ore Mining Effluent Guidelines. Of the 16 copper samples taken, 14 exceed the
daily maximum limit set by the Ore Mining Effluent Guidelines. Of the 14 zinc samples taken, 9
exceed the daily maximum limit set by the Ore Mining Effluent Guidelines.
7 The Ore Mining Effluent Guidelines do not apply to these discharges; they are used here only as screening levels.
7-3
-------
Section 7.0 - Stormwater Analysis
Table 7-2. Summary of Arizona Stormwater Monitoring Data, in mg/L
Pollutant a
Cadmium
Copper
Lead
Mercury
pH (S.U.)
TSS
Zinc
#of
Samples
15
16
15
13
14
35
14
#of
Detections
5
16
11
4
NA
35
11
Comparison to Regulatory
Levels
MSGP
Benchmark
*
*
*
0.0014
6-9
100
*
ELGs
Limit b
0.1
0.3
0.6
0.002
6-9
30
1
%of
Samples
Exceeding
ELGs
Limit
0
91
17
0
7.1
100
68
Statistical Summary
Min.
ND
0.015
ND
ND
5.8
31
ND
Avg.
0.0063
5.3
0.26
0.00013
7.3
3,200
2.2
Median
ND
4.4
0.24
0
7.7
2,000
2.2
Max.
0.034
26
0.74
0.00052
8.6
30,000
6.8
a - All metals are total recoverable.
b - Daily Maximum from Subpart J.
* - The benchmark values of some metals are dependent on water hardness.
ELGs - Ore Mining Effluent Guidelines (40 CFR Part 440).
S.U. - Standard Units.
7.3 Stormwater Monitoring Data for Montana
The Stormwater monitoring data that EPA downloaded from Envirofacts cover 11 ore
mines in Montana. Similar to the Arizona data, these data include daily maximum values for
each parameter measured but do not include monthly average values. Table 7-3 summarizes the
facilities and time periods covered by these data, as well as the parameters monitored at each
facility.
EPA copied the Envirofacts data into a spreadsheet database, and used the same methods
to process and analyze the data that were used for the Arizona DMR data (see Section 7.1).
7-4
-------
Section 7.0 - Stormwater Analysis
Table 7-3. Summary of Stormwater Monitoring Data Available for Montana Ore Mines
Facility Name
Golden Sunlight
Mines, Inc
Stillwater
Mining
Company
CR Kendall
Corporation
Asarco Black
Pine Mine
Seven Up Pete
Joint Venture
Seven Up Pete
Joint Venture
M & W Milling
& Refining
Asarco Upper
Blackfoot
Mining Complex
Golden Sunlight
Mines, Inc.
Stillwater
Mining
Company
Independent
Milling, LLC
Permit ID
MTR300012
MTR300017
MTR300026
MTR300080
MTR300085
MTR300086
MTR300139
MTR300157
MTR300199
MTR300226
MTR300260
Mine
Type3
Gold
Unknown
Gold
Silver
Gold
Gold
Gold
Lead and
Zinc
Gold
Copper
Gold
Monitoring
Period b
July 1998 -
June 2006
July 2003 -
December 2003
July 1999 -
June 2006
January 2006 -
June 2006
January 2003 -
December 2005
July 1998 -
June 2005
January 1998 -
June 2006
January 2005 -
June 2006
July 1999 -
June 2006
January 2003 -
June 2006
January 2004 -
June 2004
Monitored Parameters
_o
E
V
s
V
s
V
s
s
V
5«
13
«
s
V
s
V
s
V
s
V
s
V
n
s
s
s
s
s
s
s
s
s
-------
Section 7.0 - Stormwater Analysis
Table 7-4. Summary of Montana Stormwater Monitoring Data, in mg/L
Pollutant a
Cadmium
Copper
Lead
pH (S.U.)
TSS
Zinc
#of
Samples
66
82
80
86
85
74
#of
Detections
43
79
57
N/A
72
73
Comparison to Regulatory Levels
MSGP
Benchmark
*
*
*
6-9
100
*
ELGs
Limit b
0.1
0.3
0.6
6-9
30
1
%of
Samples
Exceeding
ELGs Limit
18
26
17
16
72
20
Statistical Summary
Min.
ND
ND
ND
2.2
ND
ND
Avg.
0.015
2.1
0.85
6.9
2,200
2.1
Median
0.00035
0.019
0.025
7.7
200
0.1
Max.
0.16
89
32
9
46,000
31
a - All metals are total recoverable. Monitoring data did not include mercury measurements.
b - Daily Maximum from Subpart J.
* - The benchmark values of some metals are dependent on the hardness of the receiving water.
ELGs - Ore Mining effluent guidelines (40 CFR Part 440).
S.U. - Standard Units.
While cadmium concentrations are higher in Montana Stormwater; copper, zinc, and TSS
concentrations are consistently higher in Arizona Stormwater.
Of the 85 TSS samples taken, 60 exceeded the daily maximum limit set by the Ore
Mining Effluent Guidelines (30 mg/L), and 49 of 85 samples exceeded the MSGP benchmark
value (100 mg/L). The average and median TSS concentrations in the Montana Stormwater data
are 2,200 and 200 mg/L, respectively.
Although the average concentrations of copper, lead, and zinc all exceed the daily
maximum limit set by the Ore Mining Effluent Guidelines, the majority of Stormwater samples
are below these limits for each of these pollutants. Average values for copper, lead, and zinc are
skewed by a few high measurements.
7.4 Conclusions
Due to the limited scope of the data that EPA was able to obtain, it is not possible to
make national conclusions about the constituents in Stormwater from mining operations, nor
about the adequacy of Stormwater controls at ore mines. The Stormwater data that EPA was able
to identify and review pertain to a small subset of mines. Moreover, the data may not represent
current conditions because they were not recently collected, and were collected during relatively
short time periods.
Based on the analysis of the Stormwater monitoring data summarized in this chapter, EPA
concludes:
• Stormwater discharges from ore mines in Montana and Arizona differ. While
cadmium concentrations were higher in the Stormwater monitoring data for
Montana; copper, zinc, and TSS concentrations were consistently higher in the
monitoring data from Arizona.
7-6
-------
Section 7.0 - Stormwater Analysis
• TSS is the only pollutant that consistently exceeds ELGs and MSGP benchmarks
in both the Arizona and Montana Stormwater monitoring data.
— In the Arizona data, all 35 TSS measurements exceeded the daily
maximum limit set by the Ore Mining ELGs (30 mg/L), and 32 of the 35
measurements exceeded the MSGP benchmark value (100 mg/L). The
average and median TSS concentrations observed in the Arizona data were
3,200 and 2,000 mg/L, respectively.
— In Montana, 60 of 85 TSS measurements exceeded the daily maximum
limit set by the Ore Mining ELGs (30 mg/L), and 49 of 85 measurements
exceeded the MSGP benchmark value (100 mg/L). The average and
median TSS concentrations observed in the Montana data were 2,200 and
200 mg/L, respectively.
• Two other pollutants in the Arizona monitoring data consistently exceed ELGs:
copper and zinc. Both average and median concentrations for each of these
pollutants exceeded the daily maximum limits set by the Ore Mining ELGs.
— Of the 16 copper measurements in the data set, 14 exceeded the daily
maximum limit set by the Ore Mining ELGs.
— Of the 14 zinc measurements in the data set, 9 exceeded the daily
maximum limit set by the Ore Mining ELGs.
7.5 Stormwater Analysis References
1. ERG. 2010a. Memo Re: Range of Pollutant Concentrations in Arizona and Montana Ore
Mining Stormwater Discharges. April 27, 2010.
2. ERG. 2010b. Site Visit Report: Arizona Copper Mines. (March). Chantilly, VA. DCN
07219.
3. U.S. EPA. 1998. Memorandum from William Telliard to Pat Sosinski (Region 3) Re:
Total vs. Total Recoverable Metals. Engineering and Analysis Division. Washington,
DC.
4. U.S. EPA. 2010. Envirofacts Database. Available online at www.epa.gov/enviro. Date
accessed: 27 January, 2010.
5. U.S. EPA, 2008. Multi-Sector General Permit For Stormwater Discharges Associated
With Industrial Activity (MSGP). Washington, DC (September). Available online at:
http://cfpub.epa.gov/npdes/stormwater/msgp.cfm. Date accessed: 27 January, 2010.
7-7
-------
Section 8.0 - High Density Sludge Treatment Technology Review
8.0 HIGH DENSITY SLUDGE TREATMENT TECHNOLOGY REVIEW
During the course of the Ore Mining Preliminary Study, EPA identified a highly efficient
treatment technology for certain types of waste streams known as high density sludge (HDS)
recycling. This technology may not be appropriate for all types of mining waste streams, but it
could be beneficial to certain mine sites depending on the volume of their waste stream and its
constituents. This section, which summarizes the HDS process, provides examples of HDS
treatment systems, and discusses permit requirements at sites using HDS. It may serve as a
resource for ore mine operators and NPDES permit writers when considering mine wastewater
treatment systems.
8.1 Background of High Density Sludge Recycling
The HDS process was developed in the early 1970's by Bethlehem Steel Corporation. It
was originally used to treat acid mine drainage and diluted waste pickle liquor discharges. The
HDS process is most practical for acidic wastewaters containing high concentrations of dissolved
metals. EPA identified one facility, the Leadville Mine District Tunnel, which uses the HDS
process to treat alkaline wastewater with high concentrations of dissolved metals.
The mining industry has used the HDS process for the past 25 years. In addition, the
following non-mining industries currently use this technology to remove heavy metals from
wastewater streams (SGS, 2009):
• Metal finishing (electro-plating and galvanizing);
• Chemical manufacturing (i.e. pigment plants);
• Smelting/refining;
• Coal preparation;
• Metal molding and casting; and
• Site remediation of heavy metals.
One benefit of the HDS process is that sludge storage and disposal costs can be much
lower than traditional sludge-generating treatment because the process generates a denser sludge.
Sludge storage and disposal costs can often exceed the initial capital costs of conventional
treatment plants over the life of their operation. Rather than disposing of the sludge after one
pass through the treatment system like traditional sludge-generating treatment systems, the HDS
process recycles the sludge back into the settling units to create a denser, more compact sludge,
lowering the total sludge volume (Leon and Zick, 1997).
Part of the reason that the HDS process produces a denser sludge is that the recycling
process creates metal compounds with a lower affinity for water. Traditional sludge-generating
treatment systems treating metal-bearing wastewaters remove metals by forming metal
hydroxides that bond with water molecules, producing wetter, less concentrated sludge. The
HDS process, however, converts metal hydroxides into metal oxide particles which have a low
affinity for water, thereby reducing the amount of interstitial water bound to the sludge and thus
reducing its volume. The HDS process, in some instances, may concentrate the sludge enough to
justify economical recovery of certain metals.
Because of the similarities between conventional lime-based treatment systems and the
HDS process, conventional systems can generally be converted via small equipment additions
JM
-------
Section 8.0 - High Density Sludge Treatment Technology Review
(e.g., small tanks, mixers, pumps, meters). However, the HDS process requires precise control,
and therefore requires experienced and knowledgeable operators for the system to function
properly (Leon and Zick, 1997).
8.2 Overview of the HDS Process
While conventional lime treatment systems add the alkali (e.g., lime, sodium hydroxide)
directly to the influent wastewater, most HDS systems mix the alkali with recycled sludge prior
to combining it into the influent wastewater. Figure 8-1 illustrates an HDS process with this type
of configuration. In contrast to this configuration, some HDS systems mix the recycled sludge
with the influent wastewater and then add the alkali.
Alkali Source
Sludge
Conditioning
Tank
Influent
Neutralization
Tank
Solids Settling
Unit
Sludge Underflow
Treated
Effluent to
Discharge
Point
Recycle
Sludge to
Disposal
Location
(Slowdown)
Figure 8-1. Simplified Schematic of the HDS Process (Leon and Zick, 1997)
The re-circulated sludge flows from the bottom of the solids settling unit back to the
beginning of the treatment system. Operators decide how much alkali to add to the system based
on differences between a pre-determined pH set point and the constant pH measurements taken
in the neutralization tank. Because of each metal's optimum solubility for precipitation and
treatment system efficiency, the pH set point is specific to the wastewater being treated. The
specific pH is determined to optimize metals removal and alkali addition rates. In some cases,
HDS systems also have the advantage of using less alkali to remove the same amount of metals
compared to conventional treatment systems, because the recycled sludge creates additional sites
for metal ions to form complexes (thereby increasing the system's treatment efficiency).
As with conventional systems, sludge must be periodically removed from the solids
settling unit to keep too much sludge from building up in the system. While conventional lime
treatment systems produce sludge containing 1 to 3 percent solids, HDS systems produce sludge
with between 25 and 35 percent solids (Leon and Zick, 1997).
8.3 Prevalence of the HDS Process
Through internet searches and interviews with HDS treatment system experts, EPA was
able to identify eight sites in the U.S. that use the HDS process to treat wastewater from mining
sites (facility location in parentheses). Most of the sites identified below are not active mine
sites and many are undergoing remediation.
8-2
-------
Section 8.0 - High Density Sludge Treatment Technology Review
Asarco Primary Lead Smelter (East Helena, MT) - According to the
Superfund Five-Year Review for this site, an HDS system treats previously
generated process wastewater and stormwater associated with the site's smelter.
The smelter is no longer active, but the two surface impoundments contributing
influent to the HDS system continue to accumulate stormwater from the site (U.S.
EPA, 1999).
Horseshoe Bend Water Treatment Plant at the Berkley Pit (Butte, MT) -
According to a site summary by the Montana Department of Environmental
Quality, the facility treats mine water using the HDS process. The Berkley Pit is a
superfund site that was formerly an open-pit copper mine; the pit also collects
seepage from mines in the surrounding area. The site summary includes permit
requirements and summary performance data for the HDS system (MDEQ, 2005).
Iron Mountain Mine Superfund Site (Redding, CA) - According to a U.S.
EPA case study, the mine drainage from the Iron Mountain Mine superfund site is
treated using an HDS system. The case study says that the system removes over
99 percent of the copper, zinc, and cadmium in the mine drainage (U.S. EPA,
2006).
Leadville Superfund Site (Leadville, CO) - The Leadville Superfund site
includes the Leadville Mine Drainage Tunnel (LMDT) and Yak Tunnel.
According to LMDT personnel, both tunnels operate HDS systems to treat mine
water. The LMDT uses sodium hydroxide to add alkalinity to the system while
the Yak Tunnel uses bulk lime (Krejci, 2009).
Mettiki Coal Mine (Oakland, MD) - An article prepared by Mettiki Coal
Company mentions that the Mettiki Coal Mine uses an HDS system to treat mine
water. In addition to treating mine water, this system treats flue gas
desulfurization wastes from wet limestone scrubbers at a local coal-fired power
plant that were previously injected into abandoned portions of the Mettiki Mine
(Ashby and Ziemkiewicz, 2007).
Red Dog Lead and Zinc Mine (Kotzebue, AK) - According to the scoping
document for the Supplemental Environmental Impact Statement for the Red Dog
Mine, the facility has two independent HDS systems that treat runoff and seepage
from ore stockpiles and tailings impoundments (U.S. EPA, 2007).
Summitville Superfund Site (Del Norte, CO) - According to a U.S. EPA
Technical Session Summary, the Summitville mine site has operated since the
1870s and became an NPL site in 1994. EPA operates an HDS system that uses
bulk lime to treat surface water run-off and groundwater seeps (U.S. EPA, 2002).
Teck-Pogo Gold Mine (Delta Junction, AK) - According to the Final
Environmental Impact Statement (FEIS) for the Pogo Mine Project, Teck-Pogo
uses an HDS system to treat mine seepage. The FEIS includes estimates of
effluent water quality based on similar treatment systems (U.S. EPA, 2003a).
8-3
-------
Section 8.0 - High Density Sludge Treatment Technology Review
8.4 Permit Requirements and Level of Treatment Required for the HDS System
EPA obtained permits for four of the eight facilities listed in Section 8.3. Table 8-1
compares effluent limits for these systems to the most stringent concentrations specified in any
of the subparts of 40 CFR Part 440. Information that that EPA reviewed shows that these HDS
systems are able to achieve pollutant removals orders of magnitude lower than limits set in 40
CFR Part 440. However, further analysis of HDS treatment costs would be needed to support any
conclusions about HDS cost effectiveness compared to other technologies currently used to treat
ore mining wastewater. A case study of HDS treatment costs and pollutant removal efficiencies
is discussed in a memo written by ERG and titled "High Density Sludge Recycling Technology"
(ERG, 2009).
8-4
-------
Section 8.0 - High Density Sludge Treatment Technology Review
Table 8-1. Permit Limits for HDS Systems Treating Discharges Associated with Ore Mining (Units are in mg/L)
Pollutant a
Cadmium
Copper
Lead
Mercury
Zinc
Lowest Concentration Set by ELGs b
Applicable
Subparts c
r 9Cr9H9J9Iv
F,G,H,J,K
F,G,H,J,K
D,J,K
C 9£ 9r ^Cr^Jrl^J 9Jv
Monthly
Avg.
0.05
0.15
0.3
0.001
0.5
Daily
Max.
0.1
0.3
0.6
0.002
1
Butte Resources
(ID: MT0000191)
Monthly
Avg.
0.0035
0.01
0.011
0.00005
0.158
Daily
Max.
0.0052
0.015
0.017
0.000075
0.238
Teck-Pogo
(ID: AK0053341)
Monthly
Avg.
0.00011
0.0022
0.0006
0.00001
0.0214
Daily
Max.
0.00022
0.0045
0.0011
0.00002
0.0429
Red Dog Mine
(ID: AK0038652)
Monthly
Avg.
0.002
0.0151
0.0081
0.00001
0.1196
Daily
Max.
0.0034
0.0437
0.0196
0.00002
0.2573
Leadville Tunnel
(ID: CO0021717)
Monthly
Avg. d'e
0.0009
0.023
0.0015
0.00013
0.084
Daily
Max. d'e
0.0012
0.023
0.032
NL
0.329
Source: NPDES Permits AK0038652, AK0053341, CO0021717, andMT0000191.
a - Pollutant concentrations are measured as total recoverable except where otherwise noted.
b - ELGs are presented for comparison purposes only.
c - Subparts codes:
G: Nickel
H: Vanadium (mined alone - not as a byproduct)
J: Copper, Lead, Zinc, Gold, Silver, and Molybdenum
K: Platinum
C: Uranium, Radium, and Vanadium.
D: Mercury
E: Titanium
F: Tungsten
c - Limits are for potentially dissolved concentrations.
d - Although the permit sets limits for both the high-flow and low-flow seasons, limits are shown for the high-flow season only.
NL - No limit.
8-5
-------
Section 8.0 - High Density Sludge Treatment Technology Review
8.5 Observations about HDS
Based on information cited in this section, EPA made the following general observations
about HDS.
• Conventional lime-softening systems can be converted to HDS systems via small
equipment additions (e.g., tanks, pumps, meters);
• While conventional lime treatment systems produce sludge containing between 1
to 3 percent solids, HDS systems generally produce sludge between 25 and 35
percent solids;
• Use of the HDS system results in lower sludge storage and disposal costs;
• The HDS system provides for better removal of certain metals (e.g., cadmium,
zinc) in some cases than a conventional lime precipitation system;
• In some cases, it may be possible to economically recover metals from the dense
sludge produced by the HDS process; and
• The four HDS systems for which EPA obtained a permit were discharging treated
effluent with cadmium, copper, lead, and mercury concentrations at least an order
of magnitude lower than 40 CFR Part 440 limits.
8.6 High Density Sludge Treatment Technology References
1. Ashby, J. and P. Ziemkiewicz. 2007. Wet FGD Placement at the Mettiki Mine in
Maryland. Prepared by Mettiki Coal, LLC, Oakland, MD.
2. Dehler, G., S. Duranceau, D. Laliberte, T. Richardson. 1995. Full-Scale Implementation
of a Carbonic Acid Aeration System for Hydrogen Sulfide Removal. Florida Water
Resources Journal.
3. ERG. 2009. Memo Re: High Density Sludge Recycling Technology. Chantilly, VA.
4. Krejci, Chris. 2009. Notes from Telephone Conference with Janelle Ortiz, Bureau of
Reclamation.
5. Leon, M. and R. Zick. 1997. Dense Sludge Process for Reduced AMD Sludge Disposal.
Prepared by Chester Engineers, Pittsburgh, Pennsylvania. Available online at:
http://wvmdtaskforce.com/proceedings/97/97ZIC/97ZIC.HTM. Date accessed: August
10, 2009.
6. Montana Department of Environmental Quality. 2005. Butte Mine Flooding Superfund
Site (Berkeley Pit).
7. SGS Group. High Density Sludge (HDS) Process.
http ://www. sgs. com/metallurgy _hom e_v2/services/environmental_sustainable/hi gh-
density-sludge-hds-process.htm. Date Accessed: August 10, 2009.
8. South Florida Water Management District. 1998. UEC Water Supply Plan Support
Document
9. U.S. EPA, 1983. Treatability Manual - Volume I. Treatability Data. Washington, DC.
-------
Section 8.0 - High Density Sludge Treatment Technology Review
10. U.S. EPA, 1983. Treatability Manual - Volume III. Technologies. Washington, DC.
11. U.S. EPA. 1998. Environmental Protection Agency Authorization to Discharge Under the
National Pollutant Discharge Elimination System AK0038652 - Red Dog Mine. DCN
05537.
12. U.S. EPA. 1999. Five-Year Review: East Helena Smelter Superfund Site (NPL Site No.
30). Prepared by U.S. EPA Region 8, Helena, MT.
13. U.S. EPA. 2002. Technical Support Project: Technical Session Summary. Prepared by
U.S. EPA. Denver, Colorado.
14. U.S. EPA. 2003a. Final Environmental Impact Statement - Pogo Gold Mine Project.
Prepared by U.S. EPA Region 10, Seattle, WA.
15. U.S. EPA. 2003b. EPA and Hardrock Mining: A Source Book for Industry in the
Northwest and Alaska Appendix E: Wastewater Management. Prepared by U.S. EPA
Region 10, Seattle, WA.
16. U.S. EPA. 2004. Environmental Protection Agency. Authorization to Discharge Under
the National Pollutant Discharge Elimination System AK0053341 - Teck-Pogo, Inc.
DCN 05541.
17. U.S. EPA. 2006. Abandoned Mine Lands Case Study: Iron Mountain Mine. Prepared by
U.S. EPA.
18. U.S. EPA, 2007. Scoping Document for the Red Dog Mine Extension - Aqqaluk Project
SEIS. Prepared by U.S. EPA Region 10, Seattle, WA.
19. U.S. EPA. 2008. Environmental Protection Agency Authorization to Discharge Under the
National Pollutant Discharge Elimination System CO0021717 - Leadville Mine Drainage
Tunnel.
8-7
-------
Appendix A
NUMERIC LIMITS SPECIFIED IN THE ORE MINING EFFLUENT GUIDELINES
-------
Appendix A
Table A-l. Monthly Average Limits from Effluent Guidelines for Ore Mining Operations
Subpart
A
B
C
D
E
F
G
H
I
J
K
M
Ore Type
Iron Ore
Aluminum Ore
Uranium, Radium, and
Vanadium Ores
Mercury Ore
Titanium Ore
Tungsten Ore
Nickel Ore Subcategory
Vanadium Ore
Antimony Ore
Copper, Lead, Zinc, Gold,
and Silver Ores
Copper Ores
Gold and Silver Ores
Molybdenum
Platinum Ores
Gold Ores (Placer Mining)
Discharge Sources
Mine Drainage and Mills
Mine Drainage
Mine Drainage
Mills using acid or alkaline
leach
Mine Drainage
Mills
Mine Drainage (Lode Deposits)
Mills
Mine Drainage (Dredge Mines)
Mine Drainage and Mills
Mine Drainage and Mills
Mine Drainage and Mills
Mine Drainage and Mills
Mine Drainage
Froth Flotation Mills
Leach processes
Cyanide mills
Mine drainage
Mill Discharges
Mine Drainage
Mill Discharges
Process Water Discharges
ELG Level
BPT/BAT/NSPS
BPT/BAT/NSPS b
BPT/BAT/NSPS c
BPT
BPT/BAT/NSPS d
BPT/BAT/NSPS
BPT/BAT/NSPS f
BPT/BAT/NSPS g
BPT/BAT/NSPS h
BPT/BAT/NSPS '
BPTJ
BPTk
N/A
BPT/BAT/NSPS '
BPT/BAT/NSPS m
BPT/BAT/NSPS
BPT/BAT/NSPS
BPT/BAT/NSPS n
BPT/BAT °
BAT
BAT
BPT/BAT/NSPS
Required Parameters a
Al
—
1
—
—
—
As
—
—
—
0.5
—
Cd
—
—
—
—
—
Cu
—
—
—
—
—
Fe
—
0.5
—
—
—
Fe
(diss.)
1
—
—
—
—
Hg
—
—
—
—
0
Ni
—
—
—
—
0.1
Pb
—
—
—
—
—
Ra
—
—
10
10
—
Ra
—
—
3
3
—
U
—
—
2
—
—
Zn
—
—
0.5
0.5
—
COD
—
—
100
500
—
NH3
—
—
—
100
—
pH
(S.U.)
6 to 9
6 to 9
6 to 9
6 to 9
6 to 9
Settleable
Solids
(mL/L)
—
—
—
—
—
TSS
20
20
20
20
20
No Discharge e
—
—
—
—
—
—
—
0.5
0.5
0.5
—
—
0.05
0.05
0.05
—
—
0.15
0.15
0.15
1
1
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
0.3
0.3
0.3
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
0.5
—
0.5
0.5
0.5
—
—
—
—
—
—
—
—
—
—
—
—
6 to 9
6 to 9
6 to 9
6 to 9
6 to 9
6 to 9
—
—
—
—
—
—
20
20
20
20
20
20
No limits promulgated.
—
—
—
—
0.05
0.05
0.15
0.15
—
—
—
—
0
0
—
—
0.3
0.3
—
—
—
—
—
—
0.75
0.5
—
—
—
—
6 to 9
6 to 9
—
—
20
20
No Discharge e
No Discharge e
—
—
—
—
0.5
0.5
—
—
0.05
0.05
0.05
0.05
0.15
0.15
0.15
0.15
—
—
—
—
—
—
—
—
0
0
0
0
—
—
—
—
0.3
0.3
0.3
0.3
—
—
—
—
—
—
—
—
—
—
—
—
0.5
0.5
0.75
0.5
—
—
—
—
—
—
—
—
—
—
6 to 9
6 to 9
—
—
—
—
—
—
—
—
20
20
—
—
—
a - Units are mg/1 unless otherwise stated. Metals are total unless otherwise stated.
b - BAT regulates only Fe and Al.
c - TSS and pH are not regulated by BAT.
d - BAT regulates only Hg; NSPS regulates only Hg, pH, and TSS.
e - Where annual precipitation exceeds evaporation, a volume of water equal to the difference between annual precipitation and evaporation for the drainage area may be discharged subject to the limitations for mine
drainage.
AA
-------
Appendix A
f - BAT regulates Fe only.
g - BAT regulates Zn only.
h - For mines producing less than 10,000 tonnes per year, only TSS and pH are regulated. TSS limits are less stringent (30 and 50 mg/L for monthly average and daily max., respectively). Lead is not regulated in mill
discharges. BAT regulates Cd, Cu, and Zn only. NSPS regulates Cd, Cu, Zn, pH, and TSS only.
i - For mines producing less than 5,000 tonnes per year, only TSS and pH are regulated. TSS limits are less stringent (30 and 50 mg/L for monthly average and daily max., respectively). Lead is not regulated in mill
discharges.
j - For mines producing less than 5,000 tonnes per year, only TSS and pH are regulated in the mine drainage, and mill discharges are not regulated. TSS limits are less stringent (30 and 50 mg/L for monthly average and daily
max., respectively). Lead is not regulated in mill discharges.
k - Cadmium is not regulated by BPT. TSS and pH are not regulated by BAT.
1 - TSS and pH are not regulated by BAT. Under NSPS limits, no discharge is allowed from froth flotation activities
m - For mines producing less than 5,000 tonnes per year, only TSS and pH are regulated under BPT. TSS limits are less stringent (30 and 50 mg/L for monthly average and daily max., respectively). BPT does not regulate
Hg. BAT does not regulate As, pH and TSS. NSPS does not regulate As.
n - For mills processing less than 5,000 tonnes per year, only TSS and pH are regulated under BPT. TSS limits are less stringent (30 and 50 mg/L for monthly average and daily max., respectively). BPT does not regulate Hg.
BAT does not regulate As, pH and TSS. NSPS does not regulate As. Under NSPS, no discharges are allowed from froth flotation mills.
o - Limit is for instantaneous max.
A-2
-------
Appendix A
Table A-2. Daily Maximum Limits from Effluent Guidelines for Ore Mining Operations
Subpart
A
B
C
D
E
F
G
H
I
J
K
M
Ore Type
Iron Ore
Aluminum Ore
Uranium, Radium, and
Vanadium Ores
Mercury Ore
Titanium Ore
Tungsten Ore
Nickel Ore Subcategory
Vanadium Ore
Antimony Ore
Copper, Lead, Zinc, Gold,
and Silver Ores
Copper Ores
Gold and Silver Ores
Molybdenum
Platinum Ores
Gold Ores (Placer Mining)
Discharge Sources
Mine Drainage and Mills
Mine Drainage
Mine Drainage
Mills using acid or alkaline leach
Mine Drainage
Mills
Mine Drainage (Lode Deposits)
Mills
Mine Drainage (Dredge Mines)
Mine Drainage and Mills
Mine Drainage and Mills
Mine Drainage and Mills
Mine Drainage and Mills
Mine Drainage
Froth Flotation Mills
Leach processes
Cyanide mills
Mine drainage
Mill Discharges
Mine Drainage
Mill Discharges
Process Water Discharges
ELG Level
BPT/BAT/NSPS
BPT/BAT/NSPS b
BPT/BAT/NSPS c
BPT
BPT/BAT/NSPS d
BPT/BAT/NSPS
BPT/BAT/NSPS f
BPT/BAT/NSPS g
BPT/BAT/NSPS h
BPT/BAT/NSPS '
BPTJ
BPTk
N/A
BPT/BAT/NSPS '
BPT/BAT/NSPS m
BPT/BAT/NSPS
BPT/BAT/NSPS
BPT/BAT/NSPS n
BPT/BAT °
BAT
BAT
BPT/BAT/NSPS
Required Parameters a
Al
—
2
—
—
—
As
—
—
—
1
—
Cd
—
—
—
—
—
Cu
—
—
—
—
—
Fe
—
1
—
—
—
Fe
(diss.)
2
—
—
—
—
Hg
—
—
—
—
0
Ni
—
—
—
—
0.2
Pb
—
—
—
—
—
Ra
—
—
30
30
—
Ra
—
—
10
10
—
u
—
—
4
—
—
Zn
—
—
1
1
—
COD
—
—
200
—
—
NH3
—
—
—
—
—
pH
(S.U.)
6 to 9
6 to 9
6 to 9
6 to 9
6 to 9
Settleable
Solids
(mL/L)
—
—
—
—
—
TSS
30
30
30
30
30
No Discharge e
—
—
—
—
—
—
—
1
1
1
—
—
0.1
0.1
0.1
—
—
0.3
0.3
0.3
2
2
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
0.6
0.6
0.6
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
1
—
1
1
1
—
—
—
—
—
—
—
—
—
—
—
—
6 to 9
6 to 9
6 to 9
6 to 9
6 to 9
6 to 9
—
—
—
—
—
—
30
30
30
30
30
30
No limits promulgated.
—
—
—
—
0.1
0.1
0.3
0.3
—
—
—
—
0
0
—
—
0.6
0.6
—
—
—
—
—
—
1.5
1
—
—
—
—
6 to 9
6 to 9
—
—
30
30
No Discharge e
No Discharge e
—
—
—
—
1
1
—
—
0.1
0.1
0.1
0.1
0.3
0.3
0.3
0.3
—
—
—
—
—
—
—
—
0
0
0
0
—
—
—
—
0.6
0.6
0.6
0.6
—
—
—
—
—
—
—
—
—
—
—
—
1
1
1.5
1
—
—
—
—
—
—
—
—
—
—
6 to 9
6 to 9
—
—
—
—
—
—
—
0.215
30
30
—
—
—
a - Units are mg/1 unless otherwise stated. Metals are total unless otherwise stated.
b - BAT regulates only Fe and Al.
c - TSS and pH are not regulated by BAT.
d - BAT regulates only Hg; NSPS regulates only Hg, pH, and TSS.
e - Where annual precipitation exceeds evaporation, a volume of water equal to the difference between annual precipitation and evaporation for the drainage area may be discharged subject to the limitations for mine
drainage.
f - BAT regulates Fe only.
-------
Appendix A
g - BAT regulates Zn only.
h - For mines producing less than 10,000 tonnes per year, only TSS and pH are regulated. TSS limits are less stringent (30 and 50 mg/L for monthly average and daily max., respectively). Lead is not regulated in mill
discharges. BAT regulates Cd, Cu, and Zn only. NSPS regulates Cd, Cu, Zn, pH, and TSS only.
i - For mines producing less than 5,000 tonnes per year, only TSS and pH are regulated. TSS limits are less stringent (30 and 50 mg/L for monthly average and daily max., respectively). Lead is not regulated in mill
discharges.
j - For mines producing less than 5,000 tonnes per year, only TSS and pH are regulated in the mine drainage, and mill discharges are not regulated. TSS limits are less stringent (30 and 50 mg/L for monthly average and daily
max., respectively). Lead is not regulated in mill discharges.
k - Cadmium is not regulated by BPT. TSS and pH are not regulated by BAT.
1 - TSS and pH are not regulated by BAT. Under NSPS limits, no discharge is allowed from froth flotation activities
m - For mines producing less than 5,000 tonnes per year, only TSS and pH are regulated under BPT. TSS limits are less stringent (30 and 50 mg/L for monthly average and daily max., respectively). BPT does not regulate
Hg. BAT does not regulate As, pH and TSS. NSPS does not regulate As.
n - For mills processing less than 5,000 tonnes per year, only TSS and pH are regulated under BPT. TSS limits are less stringent (30 and 50 mg/L for monthly average and daily max., respectively). BPT does not regulate Hg.
BAT does not regulate As, pH and TSS. NSPS does not regulate As. Under NSPS, no discharges are allowed from froth flotation mills.
o - Limit is for instantaneous max.
A-4
-------
Appendix B
SUMMARY OF PERMITTED DISCHARGES COVERED BY THE ORE MINING
POINT SOURCE CATEGORY
-------
Appendix B
Table B-l. Summary of Permitted Discharges Covered by the Ore Mining Point Source
Category a
State b
AK
AZ
CO
MT
ID
CA
MN
WY
NV
TN
UT
MO
NM
SD
FL
SC
WA
MI
AR
PA
VA
AL
NC
NJ
NY
OR
wv
GA
IL
LA
ND
NE
Total
Facility Counts
#of
Major
NPDES
IDs
5
6
9
2
5
1
2
2
1
9
2
7
5
4
3
0
1
2
1
0
0
0
0
0
2
0
0
0
0
0
0
0
69
#of
Minor
NPDES
IDs
35
36
23
24
22
19
18
16
14
2
5
0
1
o
5
2
5
5
2
o
J
3
o
3
2
2
2
0
2
2
256
Total # of
Facilities
40
32
29
22
21
19
17
16
13
10
7
6
6
6
5
5
5
4
o
J
3
o
3
2
2
2
2
2
2
289
Type of Permit
#of
Individual
Permits
15
11
22
11
14
9
20
6
5
11
4
7
6
6
5
2
3
4
2
0
3
1
0
2
2
2
0
1
1
1
1
1
178
# of General
Stormwater
Permits c
25
31
10
15
13
11
0
12
10
0
3
0
0
1
0
3
3
0
2
3
0
1
2
0
0
0
2
0
0
0
0
0
147
Available Discharge Data
# of Minor
Permit IDs
with
Discharge
Data
1
2
18
22
4
0
13
4
0
2
2
0
1
2
2
2
1
2
1
0
0
2
0
1
0
1
0
1
1
0
0
1
86
#of
General
Permit IDs
with
Discharge
Datad
0
0
5
14
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
21
%of
Minors
with
Discharge
Data6
3%
6%
78%
92%
18%
0%
72%
25%
0%
100%
40%
NA
100%
67%
100%
40%
20%
100%
33%
0%
0%
100%
0%
50%
NA
50%
0%
100%
100%
0%
0%
100%
46%
a - Excludes Mechanical Placer Mining and Suction Dredge Mining.
b - Listed in descending order of total number of facilities.
c - Includes multi-sector general Stormwater permits, general Stormwater permits for mining and oil and gas only,
and general construction Stormwater permits.
d - Included in the column titled "# of Minor Permit IDs with Discharge Data."
e - Includes general Stormwater permits and industrial permits.
B-l
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