Ore Mining and Dressing Preliminary Study 

Report 

September 2011 

 EPA-820-R-10-025 
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 Stormwater 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 (ICISNPDES).................................................................................................... 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 QualityBased Permit Limits ............................................................................................. 4-4

4.4 Ore Mining Regulatory Framework References .................................................. 4-4

 

i 
CONTENTS (Continued) 

Page 

ii 

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]).
iii 

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
iv

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
Section 1.0 – Introduction 

1-1 

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 
Section 1.0 – Introduction 

1-2 

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.) 
Section 1.0 – Introduction 

1-3 

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 × 2.6 = 104) and 20 pounds of nickel (20 × 0.11 

 

1

 Available online at http://www.epa.gov/superfund/sites/npl. 
Section 1.0 – Introduction 

1-4 

= 2.2), releases 106.2 toxic weighted pounds to surface water. Another facility, discharging 30 

pounds of cadmium (30 × 2.6 = 78) and 100 pounds of nickel (150 × 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. 
Section 1.0 – Introduction 

1-5 

• 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., Hilliard, 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. EPAHQ-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). 
Section 2.0 – Data Sources 

2-1 

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 a

• Toxics Release Inventory 

• Discharge Monitoring Report (DMR) Databases 

– Permit Compliance System (PCS) 

– Integrated Compliance Information System and National Pollutant Discharge Elimination System (ICISNPDES) 

– 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: 
Section 2.0 – Data Sources 

2-2 

• 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: 
Section 2.0 – Data Sources 

2-3 

• 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 SIC and Description 

Facilities by Type of NPDES Permit # of Facilities 

with 

Discharge 

Major Minor Total Data 

A 1011: Iron Ores 5 23 28 4 

J 1021: Copper Ores 11 15 26 5 

J 1031: Lead/Zinc Ores 23 17 40 22 

J,M 1041: Gold Ores a 13 118 131 10 

J 1044: Silver Ores 1 24 25 1 

J 1061: Ferroalloy Ores (Except Vanadium) 5 5 10 4 

NA 1081: Metal Mining Services 0 3 3 0 

C 1094: Uranium, Radium, Vanadium Ores 7 28 35 4 

Others b 1099: Metal Ores, NEC 4 20 24 4 

Total 69 253 322 c 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. 
Section 2.0 – Data Sources 

2-4 

2.1.3 Envirofacts 

To augment DMR data available from EPA’s annual review databases (PCS, ICISNPDES), 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 

stormwater permits). Montana was the only state in Envirofacts with stormwater 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.epaecho.gov/echo) to help develop its ore mining facility list. Similar to the TRI and the PCS/ICISNPDES 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/waters10/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). 
Section 2.0 – Data Sources 

2-5 

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 Agency Information Provided 

Date of 

Response 

Minnesota Minnesota Pollution Control Agency Facility List & Discharge Data 7/22/2009 

Missouri Missouri Department of Natural Resources Facility List 7/27/2009 

New Mexico New Mexico Environment Department Facility List 7/7/2009 

Arizona Arizona Department of Environmental Quality Facility List 8/4/2009 

Region 8 EPA Facility List 3/13/2009 

Region 9 EPA Facility List & Discharge Data 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; 
Section 2.0 – Data Sources 

2-6 

• Lead; 

• Molybdenum; 

• Silver; 

• Titanium; and 

• Zinc. 

2.3.3 Leadville Mine Drainage Tunnel (LMDT) 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. EPA821-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/ec0221sg1.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. MPCA. 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 

2-7 

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 Stormwater Discharges. April 27, 2010. 
Section 3.0 – Profile of the Ore Mining and Dressing Point Source Category 

3-1 

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 

SubpartSubcategory 

Title

Related SIC 

Code(s)

Related NAICS 

Code(s) Subcategory Applicability

A Iron Ore 1011: Iron Ores 212210: Iron Ores Iron Ore Mines and Mills using Physical 

or Chemical Separation or Magnetic & 

Physical Separation in the Mesabi 

Range 

B Aluminum Ore 1099: 

Miscellaneous 

Metal Ores, NEC 

212299: All Other Metal 

Ores 

Bauxite Mines Producing Aluminum 

Ore 

C Uranium, 

Radium, & 

Vanadium Ores 

1094: UraniumRadium-Vanadium 

Ores 

212291: UraniumRadium-Vanadium OresOpen-Pit or Underground Mines and 

Mills using Acid Leach, Alkaline 

Leach, or Combined Acid & Alkaline 

Leach to Produce Uranium, Radium, & 

By-product Vanadium 

D Mercury Ore 1099: 

Miscellaneous 

Metal Ores, NEC 

212299: All Other Metal 

Ores 

Open-Pit or Underground Mercury Ore 

Mines and Mills using Gravity 

Separation or Froth-Flotation 

E Titanium Ores 1099: 

Miscellaneous 

Metal Ores, NEC 

212299: All Other Metal 

Ores 

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 

F Tungsten Ore 1061: Ferroalloy 

Ores, Except 

Vanadium 

212234: Copper and 

Nickel Ores 

Tungsten Mines and Mills using Gravity 

Separation or Froth-Flotation 

G Nickel Ore 1061: Ferroalloy 

Ores, Except 

Vanadium 

212234: Copper and 

Nickel Ores 

Nickel Ore Mines and Mills 

H Vanadium Ore 

(Mined Alone, 

not as Byproduct) 

1094: UraniumRadium-Vanadium 

Ores 

212291: UraniumRadium-Vanadium OresVanadium Ore Mines and Mills 

I Antimony Ore 1099: 

Miscellaneous 

Metal Ores, NEC 

212299: All Other Metal 

Ore Mining 

Antimony Ore Mines and Mills 
Section 3.0 – Profile of the Ore Mining and Dressing Point Source Category 

3-2 

Table 3-1. Ore Mining Category Subcategory Applicability 

SubpartSubcategory 

Title

Related SIC 

Code(s)

Related NAICS 

Code(s) Subcategory Applicability

J Copper, Lead, 

Zinc, Gold, 

Silver, & 

Molybdenum 

Ores 

1021: Copper Ores 

1031: Lead and 

Zinc Ores 

1041: Gold Ores 

1044: Silver Ores 

1061: Ferroalloy 

Ores, Except 

Vanadium 

212234: Copper and 

Nickel Ores 

212231: Lead and Zinc 

Ores 

212221: Gold Ores 

212222: Silver Ores 

212299: All Other Metal 

Ores 

Copper, Lead, Zinc, Gold, Silver, & 

Molybdenum Ore Open-Pit or 

Underground Mines, except for Placer 

Deposits, and Mills using FrothFlotation and/or Other Separation 

Techniques; Mines and Mills using 

Dump, Heap, In-Situ Leach, or VatLeach 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 

K Platinum Ore 1099: 

Miscellaneous 

Metal Ores, NEC 

212299: All Other Metal 

Ores 

Platinum Ore Mines and Mills 

M Gold Placer 

Mine 

1041: Gold Ores 212221: Gold Ores 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 

3-3 

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 (of 40 CFR 440) 

2002 U.S. 

Economic 

Census 

Number of 

Facilities 

Reporting to 

TRI a

Number of 

Facilities with 

Discharges in 

EPA’s DMR 

Pollutant Loading 

Tool 

Estimated Total 

Number of Facilities b

A: Iron Ore 24 0 c 27 32 

C: Uranium, Radium, and 

Vanadium 

17 0 c 24 24 

J: Silver 11 3 23 25 

J: Lead/Zinc 22 19 32 37 

J: Gold 180 43 113 143 

J: Copper and Nickel Ore d 33 25 54 59 

J: Molybdenum 39 4 8 9 e

E: Titanium Ore 1 6 7 

F: Tungsten Ore 0 0 1 f

I: Antimony Ore 0 0 1 g

K: Platinum Ore 1 1 1 

D: Mercury Ore 0 0 0 h

B: Aluminum Ore 0 2 2 

Total (Excluding Placer 

Mines) 

326 96 290 345 i

M: Gold Placer Mines 0 j 0 1679 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. 
Section 3.0 – Profile of the Ore Mining and Dressin

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 

3-5 

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. 
Section 4.0 – Regulatory Framework for Ore Mining Discharges 

4-1 

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-1 

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 

4-2 

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 

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 

4-4 

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. 
Section 4.0 – Regulatory Framework fo

4-5 

Table 4-1. Comparison of Monitoring Requirements for Western States and Federal General Storm

Permit a Monitoring Requirements 

Analytes t

TSS 

TDS 

Turbidity 

pH 

Hardness 

Washington Permittee must monitor discharges four times per year until concentrations below benchmarks 

are measured for eight quarters. 

9 9 9 

2008 Federal 

MSGP (covers 

Idaho and New 

Mexico c) 

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. 

9 9 9 9 

California Permittee must monitor discharges three times per year. 9 9

Montana Permittee must monitor discharges at least twice per year until all concentrations are below 

benchmarks for three consecutive sampling events. 

9 9 

Arizona d 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. 

9 9 9 9 

Utah 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. 

9 

Nevada Permittee must monitor discharges once per year; alternatively, the permittee may submit a 

statement that these discharges will not cause exceedances of applicable WQS. 

9 9 9 9 

Wyoming Permittee must monitor discharges once per year. 9 

South Dakota Except for coal pile runoff, monitoring is not required on a routine basis. e

Colorado Monitoring is not required on a routine basis. e

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 effectivene
Section 5.0 – Review of TMDL Studies to Determine the Extent to Which Ore Mines May Be a Cause of 

Water Quality Impairments 

5-1 

5.0 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/waters10/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 

5-2 

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 Peña 

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. 

7. 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. 
Section 5.0 – Review of TMDL Studies to Determine the Extent to Which Ore Mines May Be a Cause o

5-3 

Table 5-1. TMDL Studies with Information on Active and Recently Closed Ore Mines 

TMDL Study 

Parameters 

Associated with 

Impairment 

Active and Recently Closed 

Mines b Summary of Data Available A

Pinto Creek, Pinto Creek, AZ 

Cu • Gibson Mine (closed) 

• BHP Pinto Creek Mine (active) • Carlota Copper Project (active) 

Appendix A (data and figures) is not included in the available TMDL report; some data are provided in the text of the report. 

The pardid not csurface mines. 

French Gulch, Hassayampa River, AZ 

Cd, Cu, Zn • Zonia Mine (closed) Document includes extensive in-stream 

monitoring data for metals and load estimates for all stream segments. 

No data Mine diimpairm

Pena Blanca, Pena Blanca Lake, AZ 

Hg • St. Patrick Mine (closed) Study provides concentration data from 

sediment and fish tissue samples and some concentration data from water column samples

The TMmining pexploratprovide potentia

Red River, Rio Grande to Headwaters. New Mexico 

Al, turbidity, and sediment 

• Molycorp Questa Mine (active) Document includes in-stream monitoring data 

for aluminum, benthic macroinvertebrates, stream flow, turbidity, and TSS; it does not provide data for any mine sites. 

None. 

Bryant Creek, Doud Springs, NV 

As, Cu, Fe, Ni, temperature, turbidity, TSS 

• Leviathan Mine (closed) Document includes statistical summary of 

stream flow, arsenic, iron, turbidity, and TSS measurements in creek. No data are provided for mine sites. 

Althougreferencdocumethe Levi

Lower Similkameen River, Oroville, WA 

As • Similco Mine (active) 

• Dankoe Mine (active) • Corona Nickel Plate Mine 

(active) 

• Cadorado Mine (active) • (All in Canada) 

Document includes in-stream monitoring data for arsenic. No data are provided for mine sites. 

The TMactive mportion watershmention 

Trinity River, Trinity River Basin, CA 

Sediment • Deiner Mine (closed) 

• La Grange (closed) 

Study estimates sediment loads from major sources. 

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. 
Section 5.0 – Review of TMDL Studies to Determine the Extent to Which Ore Mines May Be a Cause of 

Water Quality Impairments 

5-4 

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. 
Section 6.0 – Process Water Discharges 

6-1 

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 EPA’s DMRLoads2007 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 NPID Name Location 

Total 

Pounds 

Released a TWPE

1 CO0000248 Climax Mine Summit County, CO 225,030,925 50,502 

2 MN0055301 Northshore Mining/Silver Bay Silver Bay, MN 4,364,800 40,981 

3 MO0100226 Doe Run Resources Co Viburnum, MO 17,001,883 28,207 

4 AK0053341 Teck-Pogo Inc Delta Junction, AK 3,776,218 17,714 

5 UT0000051 Kennecott Copper Co Magna, UT 142,677,370 11,517 

6 ID0000027 U.S. Silver Corporation Wallace, ID 21,995 9,072 

7 MO0000086 Doe Run Company Viburnum, MO 133,893 6,920 

8 MO0001856 Doe Run Resources Co Viburnum, MO 1,821,703 5,022 

9 MO0001848 Doe Run Resources Corp Viburnum, MO 2,412,669 3,121 

10 SD0026883 LAC Minerals Central City, SD 4,972,369 2,004 

11 CA0081876 Mammoth,Sutro,Keystone Et Al Redding, CA 5,836 1,854 

12 NY0001791 Balmat Mines & Mill Balmat, NY 15,969,640 1,351 

13 SD0025852 Wharf Resources (USA) Lead, SD 3,071,229 1,227 

14 AR0000582 Alcoa Arkansas Remediation Bauxite, AR 132,152 924 

15 MO0100218 Doe Run Company Bunker, MO 48,310 916 

16 AK0043206 Kennecott Greens Creek Mining Juneau, AK 349,176 396 
Section 6.0 – Process Water Discharges 

6-2 

Table 6-1. 2007 Discharge Summary for the Ore Mining Category 

Rank NPID Name Location 

Total 

Pounds 

Released a TWPE

17 MI0000094 Empire Iron Mining Partnership Palmer, MI 14,241,519 394 

18 TN0001732 East Tennessee Zinc Co. LLC Jefferson City, TN 77,583 373 

19 MI0038369 Tilden Mining Company L.C. Ishpeming, MI 13,320,379 315 

20 CO0024562 Carlton Tunnel Portal Site Teller County, CO 40,828 294 

21 NM0022306 Chevron Mining Inc. Questa, NM 5,670 252 

22 UT0022403 Jordanelle Ssd Park City, UT 11,017 186 

23 CO0041467 Henderson Mine, Urad Minesite Clear Creek, CO 93,143 142 

24 SD0026905 Golden Reward Mining Co. Lead, SD 4,339,129 131 

25 CO0038334 London Water Tunnel Park County, CO 1,309 95 

26 TN0061468 East TN Zinc Co., Llc Jefferson City, TN 9,530 86 

27 MN0046981 Northshore Mining Co; Cliffs MN Babbitt, MN 2,140,070 73 

28 MO0001872 Cominco American Inc Bixby, MO 5,676 71 

29 AZ0020401 Bhp Pinto Valley Operations Miami, AZ 7,079,818 51 

30 TN0001759 East Tennessee Zinc Co., LLC Mascot, TN 13,709 50 

31 AK0050571 Coeur Alaska Inc Juneau, AK 1,154,488 36 

32 CO0035394 Mt. Emmons/Keystone Mine Gunnison County, CO 1,864,673 29 

33 AK0038652 Teck Cominco Alaska Inc Kotzebue, AK 1,585,789 28 

34 TN0001741 East Tennessee Zinc Co., LLC New Market, TN 7,114 22 

35 TN0027677 East Tennessee Zinc Co., LLC Jefferson County, TN 4,487 17 

36 ID0025402 Thompson Creek Mining Challis, ID 1,064,984 16 

37 ID0026468 Hecla Mining Company Stanley, ID 653,375 16 

38 CO0038954 Platoro Joint Venture Conejos County, CO 196,805 14 

39 WA0025721 Dawn Mining Company Wellpinit, WA 1,035,549 13 

40 FL0000051 Bradford County Bradford County, FL 28,892 10 

41 NM0020532 Rio Algom Mining, LLC Mckinley County, NM 6,726 7 

42 FL0040274 E.I. Dupont De Nemour-Maxville Starke, FL 18,382 3 

43 TN0060127 O-N Minerals(Luttrell) Co. Thorn Hill, TN 5,058 2 

44 FL0000035 State Route 125 Clay County, FL 2,659 1 

45 TN0057029 Mossy Creek Mining, LLC New Market, TN 179 0 

46 NM0020435 Chino Mines Company Hurley, NM 0 0 

47 NM0028100 Rio Grande Resources Corp. Cibola County, NM 0 0 

48 NM0028169 Mineral Energy and Technology Sarquez, NM 0 0 

49 NV0023345 Esmeralda Project Gold Mine Hawthorne, NV 0 0 

50 SD0000043 Sd Science And Technology Lead, SD 0 0 

51 MT0000191 Montana Resources Butte, MT 0 0 

52 ID0000175 Hecla Mining Company Mullan, ID 0 0 

53 TN0004227 Mossy Creek Mining, LLC Elmwood, TN 37,155 0 

54 TN0029360 Mid-Tennessee Zinc Corporation Gordonsville, TN 0 0 

Source: EPA’s DMRLoads2007 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. 
Section 7.0 – Stormwater Analysis 

7-1 

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, 2010b). 

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 

7-2 

• 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 

7-3 

Table 7-1. Stormwater Monitoring Data Available for Arizona Ore Mines 

Facility Name Permit ID Mine Type

Monitoring 

Period a

Monitored Parameters 

Flow Metals pH TSS COD Hardness Turbidity N (N03 + N02) 

Copper Cities AZR05A798 Copper January 1999 – 

August 1999 9 9 9 9 

Florence AZR05A795 Copper April 1999 – 

September 1999 9 9 9 9 9 9 

Pinto Valley AZR05A796 Copper January 1999 – 

September 1999 9 9 9 9 

Morenci AZR05A711 Copper January 1999 – 

September 1999 9 9 9 9 9 9 9 

Sierrita AZR05A550 Copper January 2000 – 

December 2000 9 9 9 9 9 9 

San Manuel 

Mine 

AZR05B412 Copper July 2001 – 

September 2001 9 9 9 9 9 9 9 9 

Silver Bell AZR05A789 Copper January 1999 – 

March 2002 9 9 9 9 9 9 9 9 

Superior AZR05A800 Copper January 1999 – 

December 2000 9 9 9 9 9 9 9 9 

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. 
Section 7.0 – Stormwater Analysis 

7-4 

Table 7-2. Summary of Arizona Stormwater Monitoring Data, in mg/L 

Pollutant a

# of 

Samples 

# of 

Detections 

Comparison to Regulatory 

Levels Statistical Summary 

MSGP 

Benchmark

ELGs 

Limit b

% of 

Samples 

Exceeding

ELGs 

Limit Min. Avg. Median Max. 

Cadmium 15 5 * 0.1 0 ND 0.0063 ND 0.034 

Copper 16 16 * 0.3 91 0.015 5.3 4.4 26 

Lead 15 11 * 0.6 17 ND 0.26 0.24 0.74 

Mercury 13 4 0.0014 0.002 0 ND 0.00013 0 0.00052 

pH (S.U.) 14 NA 6 - 9 6 - 9 7.1 5.8 7.3 7.7 8.6 

TSS 35 35 100 30 100 31 3,200 2,000 30,000 

Zinc 14 11 * 1 68 ND 2.2 2.2 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). 
Section 7.0 – Stormwater Analysis 

7-5 

Table 7-3. Summary of Stormwater Monitoring Data Available for Montana Ore Mines 

Facility Name Permit ID 

Mine 

Type a

Monitoring 

Period b

Monitored Parameters 

Flow Metals pH TSS COD Hardness Turbidity N (N03 + N02) 

Golden Sunlight 

Mines, Inc 

MTR300012 Gold July 1998 – 

June 2006 9 9 9 9 9 9 

Stillwater 

Mining 

Company 

MTR300017 Unknown July 2003 – 

December 2003 9 9 9 9 9 9 

CR Kendall 

Corporation 

MTR300026 Gold July 1999 – 

June 2006 9 9 9 9 9 9 

Asarco Black 

Pine Mine 

MTR300080 Silver January 2006 – 

June 2006 9 9 9 9 

Seven Up Pete 

Joint Venture 

MTR300085 Gold January 2003 – 

December 2005 9 9 9 9 9 9 

Seven Up Pete 

Joint Venture 

MTR300086 Gold July 1998 – 

June 2005 9 9 9 9 9 

M & W Milling 

& Refining 

MTR300139 Gold January 1998 – 

June 2006 9 9 9 9 

Asarco Upper 

Blackfoot 

Mining Complex 

MTR300157 Lead and 

Zinc 

January 2005 – 

June 2006 9 9 9 9 9 

Golden Sunlight 

Mines, Inc. 

MTR300199 Gold July 1999 – 

June 2006 9 9 9 9 9 9 

Stillwater 

Mining 

Company 

MTR300226 Copper January 2003 – 

June 2006 No Discharges Reported 

Independent 

Milling, LLC 

MTR300260 Gold January 2004 – 

June 2004 No Discharges Reported 

a – Determined by SIC code. 

b – In some cases, monitoring data are not continuous for the period specified (some periods without data). 

Table 7-4 summarizes the Montana stormwater data and compares them to the numerical 

limits from the Ore Mining Effluent Guidelines and the benchmark concentrations from the 

Federal MSGP. 
Section 7.0 – Stormwater Analysis 

7-6 

Table 7-4. Summary of Montana Stormwater Monitoring Data, in mg/L 

Pollutant a

# of 

Samples 

# of 

Detections 

Comparison to Regulatory Levels Statistical Summary 

MSGP 

Benchmark

ELGs 

Limit b

% of 

Samples 

Exceeding 

ELGs Limit Min. Avg. Median Max. 

Cadmium 66 43 * 0.1 18 ND 0.015 0.00035 0.16 

Copper 82 79 * 0.3 26 ND 2.1 0.019 89 

Lead 80 57 * 0.6 17 ND 0.85 0.025 32 

pH (S.U.) 86 N/A 6 - 9 6 - 9 16 2.2 6.9 7.7 9 

TSS 85 72 100 30 72 ND 2,200 200 46,000 

Zinc 74 73 * 1 20 ND 2.1 0.1 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. 
Section 7.0 – Stormwater Analysis 

7-7 

• 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. 
Section 8.0 – High Density Sludge Treatment Technology Review 

8-1 

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 
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. 

8-2 

Sludge 

Conditioning 

Tank

Neutralization 

Tank

Solids Settling 

Unit

Alkali Source Influent

Sludge Underflow

Recycle

Sludge to 

Disposal 

Location 

(Blowdown)

Treated 

Effluent to 

Discharge 

Point

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. 
Section 8.0 – High Density Sludge Treatment Technology Review 

8-3 

• 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). 
Section 8.0 – High Density Sludge Treatment Technology Review 

8-4 

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). 
Section 8.0 – High Density Sludge Treat

8-5 

Table 8-1. Permit Limits for HDS Systems Treating Discharges Associated with Ore Mining (Units 

Pollutant a

Lowest Concentration Set by ELGs b

Butte Resources 

(ID: MT0000191) 

Teck-Pogo 

(ID: AK0053341) 

Red Dog Mine 

(ID: AK0038652) 

Applicable 

Subparts c

Monthly 

Avg. 

Daily 

Max. 

Monthly 

Avg. 

Daily 

Max. 

Monthly 

Avg. 

Daily 

Max. 

Monthly 

Avg. 

Daily 

Max. 

Cadmium F,G,H,J,K 0.05 0.1 0.0035 0.0052 0.00011 0.00022 0.002 0.0034 Copper F,G,H,J,K 0.15 0.3 0.01 0.015 0.0022 0.0045 0.0151 0.0437 Lead F,G,H,J,K 0.3 0.6 0.011 0.017 0.0006 0.0011 0.0081 0.0196 Mercury D,J,K 0.001 0.002 0.00005 0.000075 0.00001 0.00002 0.00001 0.00002 Zinc C,E,F,G,H,J,K 0.5 1 0.158 0.238 0.0214 0.0429 0.1196 0.2573 

Source: NPDES Permits AK0038652, AK0053341, CO0021717, and MT0000191. a – Pollutant concentrations are measured as total recoverable except where otherwise noted. b – ELGs are presented for comparison purposes only. c – Subparts codes: 

C: Uranium, Radium, and Vanadium. D: Mercury E: Titanium F: Tungsten 

G: Nickel H: Vanadium (mined alone - not as a byproduct) J: Copper, Lead, Zinc, Gold, Silver, and Molybdenum K: Platinum 

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. 
Section 8.0 – High Density Sludge Treatment Technology Review 

8-6 

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_home_v2/services/environmental_sustainable/highdensity-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 

8-7 

10. U.S. EPA, 1983. Treatability Manual – Volume 1II. 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. 
Appendix A 

NUMERIC LIMITS SPECIFIED IN THE ORE MINING EFFLUENT GUIDELINES 
A-1 

Table A-1. Monthly Average Limits from Effluent Guidelines for O

Subpart Ore Type Discharge Sources ELG Level 

Al As Cd Cu Fe 

Fe 

(diss.) H

A Iron Ore Mine Drainage and Mills BPT/BAT/NSPS — — — — — 1 — 

B Aluminum Ore Mine Drainage BPT/BAT/NSPS b 1 — — — 0.5 — — C Uranium, Radium, and 

Vanadium Ores 

Mine Drainage BPT/BAT/NSPS c — — — — — — — 

Mills using acid or alkaline leach 

BPT — 0.5 — — — — — 

D Mercury Ore Mine Drainage BPT/BAT/NSPS d — — — — — — 0 

Mills BPT/BAT/NSPS 

E Titanium Ore Mine Drainage (Lode Deposits) BPT/BAT/NSPS f — — — — 1 — — 

Mills BPT/BAT/NSPS g — — — — — — — Mine Drainage (Dredge Mines) BPT/BAT/NSPS h — — — — 1 — — 

F Tungsten Ore Mine Drainage and Mills BPT/BAT/NSPS i — 0.5 0.05 0.15 — — — 

G Nickel Ore Subcategory Mine Drainage and Mills BPT j — 0.5 0.05 0.15 — — — H Vanadium Ore Mine Drainage and Mills BPT k — 0.5 0.05 0.15 — — — 

I Antimony Ore Mine Drainage and Mills N/A 

J Copper, Lead, Zinc, Gold, 

and Silver Ores 

Mine Drainage BPT/BAT/NSPS l — — 0.05 0.15 — — 0 

Froth Flotation Mills BPT/BAT/NSPS m — — 0.05 0.15 — — 0 

Copper Ores Leach processes BPT/BAT/NSPS Gold and Silver Ores Cyanide mills BPT/BAT/NSPS Molybdenum Mine drainage BPT/BAT/NSPS n — 0.5 0.05 0.15 — — 0 

Mill Discharges BPT/BAT o — 0.5 0.05 0.15 — — 0 

K Platinum Ores Mine Drainage BAT — — 0.05 0.15 — — 0 

Mill Discharges BAT — — 0.05 0.15 — — 0 

M Gold Ores (Placer Mining) Process Water Discharges BPT/BAT/NSPS — — — — — — — 

a – Units are mg/l 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 

drainage. 
A-2 

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 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 mdischarges. 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 reg

max., respectively). Lead is not regulated in mill discharges. k – Cadmium is not regulated by BPT. TSS and pH are not regulated by BAT. l – 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 5

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 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-3 

Table A-2. Daily Maximum Limits from Effluent Guidelines for O

Subpart Ore Type Discharge Sources ELG Level 

Al As Cd Cu Fe 

Fe 

(diss.) H

A Iron Ore Mine Drainage and Mills BPT/BAT/NSPS — — — — — 2 — 

B Aluminum Ore Mine Drainage BPT/BAT/NSPS b 2 — — — 1 — — C Uranium, Radium, and 

Vanadium Ores 

Mine Drainage BPT/BAT/NSPS c — — — — — — — 

Mills using acid or alkaline leach BPT — 1 — — — — — 

D Mercury Ore Mine Drainage BPT/BAT/NSPS d — — — — — — 0 

Mills BPT/BAT/NSPS 

E Titanium Ore Mine Drainage (Lode Deposits) BPT/BAT/NSPS f — — — — 2 — — 

Mills BPT/BAT/NSPS g — — — — — — — Mine Drainage (Dredge Mines) BPT/BAT/NSPS h — — — — 2 — — 

F Tungsten Ore Mine Drainage and Mills BPT/BAT/NSPS i — 1 0.1 0.3 — — — 

G Nickel Ore Subcategory Mine Drainage and Mills BPT j — 1 0.1 0.3 — — — H Vanadium Ore Mine Drainage and Mills BPT k — 1 0.1 0.3 — — — 

I Antimony Ore Mine Drainage and Mills N/A 

J Copper, Lead, Zinc, Gold, 

and Silver Ores 

Mine Drainage BPT/BAT/NSPS l — — 0.1 0.3 — — 0 

Froth Flotation Mills BPT/BAT/NSPS m — — 0.1 0.3 — — 0 

Copper Ores Leach processes BPT/BAT/NSPS Gold and Silver Ores Cyanide mills BPT/BAT/NSPS Molybdenum Mine drainage BPT/BAT/NSPS n — 1 0.1 0.3 — — 0 

Mill Discharges BPT/BAT o — 1 0.1 0.3 — — 0 

K Platinum Ores Mine Drainage BAT — — 0.1 0.3 — — 0 

Mill Discharges BAT — — 0.1 0.3 — — 0 

M Gold Ores (Placer Mining) Process Water Discharges BPT/BAT/NSPS — — — — — — — 

a – Units are mg/l 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 

drainage. f – BAT regulates Fe only. 
A-4 

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 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 mdischarges. 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 reg

max., respectively). Lead is not regulated in mill discharges. k – Cadmium is not regulated by BPT. TSS and pH are not regulated by BAT. l – 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 5

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 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. 
Appendix B 

SUMMARY OF PERMITTED DISCHARGES COVERED BY THE ORE MINING 

POINT SOURCE CATEGORY 
Appendix B 

B-1 

Table B-1. Summary of Permitted Discharges Covered by the Ore Mining Point Source 

Category a

State b

Facility Counts Type of Permit Available Discharge Data 

# of 

Major 

NPDES 

IDs 

# of 

Minor 

NPDES 

IDs 

Total # of 

Facilities 

# of 

Individual 

Permits 

# of General 

Stormwater 

Permits c

# of Minor 

Permit IDs 

with 

Discharge 

Data 

# of 

General 

Permit IDs 

with 

Discharge 

Data d

% of 

Minors 

with 

Discharge 

Data e

AK 5 35 40 15 25 1 0 3% 

AZ 6 36 32 11 31 2 0 6% 

CO 9 23 29 22 10 18 5 78% 

MT 2 24 22 11 15 22 14 92% 

ID 5 22 21 14 13 4 0 18% 

CA 1 19 19 9 11 0 0 0% 

MN 2 18 17 20 0 13 0 72% 

WY 2 16 16 6 12 4 0 25% 

NV 1 14 13 5 10 0 0 0% 

TN 9 2 10 11 0 2 0 100% 

UT 2 5 7 4 3 2 0 40% 

MO 7 0 6 7 0 0 0 NA 

NM 5 1 6 6 0 1 0 100% 

SD 4 3 6 6 1 2 1 67% 

FL 3 2 5 5 0 2 0 100% 

SC 0 5 5 2 3 2 0 40% 

WA 1 5 5 3 3 1 0 20% 

MI 2 2 4 4 0 2 0 100% 

AR 1 3 3 2 2 1 0 33% 

PA 0 3 3 0 3 0 0 0% 

VA 0 3 3 3 0 0 0 0% 

AL 0 2 2 1 1 2 1 100% 

NC 0 2 2 0 2 0 0 0% 

NJ 0 2 2 2 0 1 0 50% 

NY 2 0 2 2 0 0 0 NA 

OR 0 2 2 2 0 1 0 50% 

WV 0 2 2 0 2 0 0 0% 

GA 0 1 1 1 0 1 0 100% 

IL 0 1 1 1 0 1 0 100% 

LA 0 1 1 1 0 0 0 0% 

ND 0 1 1 1 0 0 0 0% 

NE 0 1 1 1 0 1 0 100% 

Total 69 256 289 178 147 86 21 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.