# Ore Mining and Dressing Preliminary Study Report

September 2011

EPA-820-R-10-025

### CONTENTS

Page

1.0 I NTRODUCTION 

### ................................................................................................................. 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 D ATA 

### S OURCES 

### ................................................................................................................. 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 Discha rge 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 EP A 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 Mine ral 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 P ROFILE OF THE 

### O RE 

### M INING AND 

### D RESSING 

### P OINT 

### S OURCE 

### C ATEGORY 

### ........................ 3-1
3.1 Ore Mining and Dressing Poin t 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 R EGULATORY 

### F RAMEWORK FOR 

### O RE 

### M INING 

### D ISCHARGES 

### ............................................ 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 Fram ework References .................................................. 4-4

i

### CONTENTS (Continued)

Page

ii 5.0 R EVIEW OF 

### TMDL S TUDIES TO 

### D ETERMINE THE 

### E XTENT TO 

### W HICH 

### O RE 

### M INES 

### M AY 

### B E A 

### C AUSE OF 

### W ATER 

### Q UALITY 

### I MPAIRMENTS 

### .............................................................. 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 Im pact References .................................................... 5-2

6.0 P ROCESS 

### W ATER 

### D ISCHARGES 

### ......................................................................................... 6-1
6.1 Process Water Discharges References ................................................................. 6-2

7.0 S TORMWATER 

### A NALYSIS 

### .................................................................................................. 7-1
7.1 Quality Procedures Used to Create Analysis Spreadsheets ................................. 7-1
7.2 Stormwater Monitoring Da ta for Arizona ............................................................ 7-2
7.3 Stormwater Monitoring Da ta for Montana .......................................................... 7-4
7.4 Conclusions .......................................................................................................... 7-6
7.5 Stormwater Analysis References ......................................................................... 7-7

8.0 H IGH 

### D ENSITY 

### S LUDGE 

### T REATMENT 

### T ECHNOLOGY 

### R EVIEW 

### ........................................... 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 SPECIFI ED 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: Bagda d 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 produ ced from Morenci’s SXEW plant. All photos were taken during EPA’s site visits to Freeport McMoran c opper 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 w ith 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 Subcat egory 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 Ava ilable 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 Classificati on Depending on Wastewater Source and Management (U.S. EPA, 2003) ....................................................................................... 4-3

8-1 Simplified Schematic of the HDS Process (Leon and Zick, 1997) .................................. 8-2Section 1.0 – Introduction



### 1-1 1.0 I NTRODUCTION



### The purpose of this report is to summarize th e 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 av ailable information to determine whether additional analysis or revi sion 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 Di scharge 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 mine s, 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 pe rtaining to the two t ypes of wastewater discharged by ore mines: process wastewater (including mine drainage) and stormwater. Process
wastewater is covered under 40 CFR Part 440. St ormwater is not cove red under 40 CFR Part 440 unless it is commingled with pr ocess wastewater prio r to discharge to a surface waterbody. The comprehensiveness of the preliminary study wa s limited by incomplete national-level process wastewater discharge data, and the lack of any nationally re presentative stormwater data.

To facilitate this study, EPA id entified and collected existi ng discharge monitoring data, assessed mine-specific process wastewater discharge informa tion, reviewed available Total Maximum Daily Load (TMDL) reports, reviewed mi ne site stormwater discharge information for 19 mines in Arizona and Montana, and reviewed an industrial wastewat er 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 pertai ns 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 pro cess of extracting ore from the earth, which mostly involves either open p it excavation or deep mining. The term “dressing,” no longer used by the ore mining industry, has been replaced by th e term “beneficiation.” They mean the same thing, however, which is the initial attempt to liberate and concentrate the mineral from theSection 1.0 – Introduction



### 1-2 mined rock. Beneficiation operations incl ude crushing, grinding, washing, dissolution, crystallization, filtration, sorting, sizing, drying, pelletizi ng, briquetting, or roasting in preparation for leaching, gravity concentrati on, magnetic separation, electrostatic separation, flotation, amalgamation, and h eap, dump, vat, tank, and in-situ leaching.

Mineral processing operations generally follow beneficiation and incl ude techniques that change the chemical composition of the ore mine ral, such as ion exch ange, solvent extraction, smelting, electrolytic refining, and acid attack or digestion. The physical st ructure of the mineral is often destroyed, producing products and waste streams that are not earthen in character, bearing little or no resemblance to th e 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 materi al 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, ove rburden management is generally less rigorous. Waste rock is generally placed in engi neered structures with stormwater run-off controls in a part of the mine away from th e ore body. Overburden piles may or may not need
stormwater controls.

Wastes from beneficiation pr ocesses 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 cove red under 40 CFR Part 440.

Total waste (waste rock and tailings) produced during the ex traction and beneficiation of minerals can range from 10 percent of the total material removed fr om 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 or e 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 a nd reclamation work has begun.

Active mines, moreover, produce a saleable pr oduct, whether or not extraction operations at the site are currently unde rway. For example, a mine wher e extraction has stopped, but heap leaching of ore is being performed is considered an active mine. In cont rast, inactive mines are those that are not currently producing a saleab le 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 aba ndoned mine sites in 32 states compiled by the Mineral Policy Center, an environmental rese arch and advocacy group (Lyon and others, 1993.)Section 1.0 – Introduction



### 1-3 The Superfund Final National Priority List 1 

### of 1277 Superfund sites includes approximately 23 mines.

Process Wastewater, Mine Dr ainage, and Stormwater

There are three types of wastewater discharg ed by ore mines: process wastewater, mine drainage, and stormwater. Process wastewater an d 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 prio r to discharge to a surface waterbody. Table 1-1 presents legal
definitions of these terms.

Table 1-1. Categories of Discha rges 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 ra w 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 si phoned 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 pl ant. ... (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 Toxi c Weighted Pound Equivalents

Chemical pollutants discharged to surf ace water have different toxicities. EPA normalizes the toxicities of the various pollutant s 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, ha s 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 discharg es on a constant toxi city basis expressed as Toxic Weighted Pound Equivalents (TWPE). TWPE values allow EPA to rank and compare
facilities and industries th at discharge waste streams with di fferent 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 su rface 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 Ke y 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 ye ar for which quality-checked data are available, approximately two pe rcent of the estimated 294 ore mining facilities with NPDES permits were responsible for approximately 90 pe rcent of toxic weighted discharges by the industry 2 

### . Given that a small percentage of activ e mines account for the majority of toxic weighted discharges, discharge issues are be st addressed through permitting, compliance, and
enforcement activities rather th an 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 Ariz ona and Montana. The data were too limited, however, to support regional or na tional conclusions about stormwat er discharges at ore mining sites. Statistically representative sampling of st ormwater 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 whic h stormwater from active mines ma y 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 limitati ons for waterbodies that have been determined to be impaired by EPA or by authorized stat e permitting authorities. EPA conducted a keyword search of 7,760 TMDL reports and found only se ven instances where active ore mines were named among the sources within impaired wate rsheds. None of the TMDL documents, however, definitively stated that impairments resulted from active mines.

Interviews with EPA regional staff did not id entify 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 inadequa te 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 a nd 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 su mmary of the Ore Mining Category including a description of industry sectors as well as a facility list.

• 

### Section 4.0 summarizes the laws and regulati ons 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 pr ocess wastewater discharges from the Ore Mining Category.

• 

### Section 7.0 discusses EPA’s analysis of monitoring data for stormwater discharges from ore mining operations.

• 

### Se ction 8.0 discusses EPA’s evaluati on 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. Washi ngton, DC (February).

5. U.S. EPA. 2003. EPA and Hard rock Mining: A Sourcebook for Industry in the Northwest and Alaska. Seattle, Washington (January).

6. E RG. 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 D ATA 

### S OURCES



### This section summarizes the available inform ation that EPA identified and reviewed to better understand process water and stormwater di scharges by the ore mining industry. More specifically, EPA reviewed info rmation 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 We ighted Pound Equivalent Loads; and

• 

### Assess potential impacts of discha rges on surface water quality.

Table 2-1 summarizes the main data sources us ed 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 Informati on System and National Pollutant Discharge Elimination System (ICISNPDES)
– Envirofacts – DMR Pollutant Loading Tool

• Enforcement and Complian ce 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 Efflue nt 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 ch aracterizing 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 conditi ons because the most recent data are typically from 2006; and

• 

### Di scharge data are incomplete. Not all mon itoring 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 EP A’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 TR I 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 repo rting 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 NAI CS codes are available for the ore mining industry:

• 

### 212210: Iron ore mining;

• 

### 212234: Copper ore and ni ckel 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

• 

### 2131 14: Support activities for metal mining.

The Technical Support Document for the Annua l Review of Existing Effluent Guidelines
and Identification of Potential New Point Sour ce Categories contains a thorough discussion of how EPA uses TRI water discharge information in its annual efflue nt guidelines planning process (U.S. EPA, 2009).

2 .1.2 Discharge Monitoring Report Data from th e 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 subm it 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 bot h databases, as was necessary to prepare the Ore Mining Preliminary Study.

The DMR data used in the Prel iminary 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 Prelimin ary 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 discharg e data are only availa ble for facilities classified as major dischargers. Very little data are available for faciliti es classified as minor dischargers because states are not required to upload data on minor fac ilities 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 pollu tant loading;

• 

### Public health impact;

• 

### Water quality factors; and

• 

### Prox imity to coastal waters.

Table 2-2. Summary of Ore Mini ng 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
Data Major Minor Total

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 iden tified 1,869 gold placer and suction dredge mining operations permitted under a genera l 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 EP A’s annual review databases (PCS, ICISNPDES), EPA reviewed ore mining DMR data avai lable through Envirofacts, an online database that stores data for various EPA programs (e.g., EPCRA, CWA, RCRA). Envi rofacts is available online at http:// www.epa.gov/enviro . It functions as a central repository of permitting information, including monitoring data for some f acilities. 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 NPDE S 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 st ormwater 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 li mited 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_sear ch), 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 comple ted studies that have not yet been added to the TMDL database. Approximately 82 per cent 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 de termine whether they had recen t mining stormwater data of sufficient quality and representativeness for us e 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 Envi rofacts). These data were not adequate to support any nationa l 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 st ates 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 No n-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 Syst em (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 wa s taken (2000), and f acilities that were c ounted 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 augmen t its ore mining facility list. EPA compares
the number of mines identified in other data so urces 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 (L MDT) 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 Recl amation 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 discus ses 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 ExistingEffluent Guidelines and Identification of Potential New Point Source Categories. EPA821-R-09-007. Washingt on, 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 Faci lities in EPA Region 8. (March 13). DCN
07221.

7. EPA Region 9. 2009. Discharge Data for Select Arizona Ore Mining Fa cilities. (July 24).
DCN 07225.

8. MPCA. Minnesota Pollution C ontrol Agency. 2009. List of Ore Mining Facilities in Minnesota. (July 22). DCN 07223.

9. MPCA. Minnesota Pollution Control Agen cy. 2009. Discharge Data for Select Ore Mining Facilities in Minnes ota. (July 22). DCN 07223.Section 2.0 – Data Sources



### 2-7 10. ADEQ. Arizona Department of Environm ental Quality. 2009. List of Ore Mining Facilities in Arizona. (March 13). DCN 07226.

11. MDNR. Missouri Department of Natural Resour ces. 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 Conc entrations in Ariz ona 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 P ROFILE OF THE 

### O RE 

### M INING AND 

### D RESSING 

### P OINT 

### S OURCE 

### C ATEGORY



### 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 su mmary of mining processes.

3. 1 Ore Mining and Dressing Point Source Subcategories

The Ore Mining and Dressing Point Source Ca tegory, codified in 40 CFR Part 440, is divided into the subcategories shown in Table 3-1

.

Table 3-1. Ore Mining Categor y Subcategory Applicability

Subpart Subcategory
Title Related SIC Code(s) Related NAICS Code(s) Subcategory Applicability

A Iron Ore 1011: Iron Ores 212210: Iron Or es 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 Ores Open-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 Ores Vanadium Ore Mines and Mills

I Antimony Ore 1099:
Miscellaneous Metal Ores, NEC 212299: All Other Metal Ore Mining Antimony Ore Mines and MillsSection 3.0 – Profile of the Ore Mining and Dressing Point Source Category



### 3-2 Table 3-1. Ore Mining Categor y Subcategory Applicability

Subpart Subcategory
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 PlacerDeposits, and Mills using FrothFlotation and/or Other Separation Techniques; Mines and Mills usingDump, 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 mi nes, 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 differe nt mine types across the U.S.

EPA developed the facility list starting w ith the TRI and PCS/IC IS-NPDES databases. EPA augmented these data with US Census in formation from the 2005 to 2007 USGS Minerals Yearbook and Mineral Commodity Summaries, along with faci lity lists provided by EPA regional offices and state agencies.

As discussed in Section 2, the exact number of active mi nes, 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 differe nt 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 inco mplete. EPA developed the facility list starting
with the TRI and PCS/ICIS-NPDES databases. EP A attempted to correlate facilities between data sources using available information, but so me 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 fo r some subcategories because no single data source contained all of the known f acilities. EPA augmented data from TRI and
PCS/ICIS-NPDES with US Census informa tion and from the 2005 to 2007 USGS MineralsSection 3.0 – Profile of the Ore Mining and Dressing Point Source Category



### 3-3 Yearbook and Mineral Commodity Summaries, along with faci lity lists provided by EPA regional offices and state agencies.

Table 3-2. Estimated Number of Facili ties 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 (inc luding facilities without discharges).
b – EPA estimated the total number of facilities in each da tabase by compiling USGS , Census, Enviro facts, TRI, and DMR data into one list (see DCN 07228). EPA identified situations where a f acility 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 pr incipal product. EPA has not identified any U.S. mines for which nickel is the principal product. e – Assumes that all facilities reporting SIC 1061 (F erroalloy 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 mine s 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 Miningand Dressing Point Source CategoryFigure 3-1. Ore Mines in the U.S. byType (Based on Primary Commodity)3-4Section 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 proce sses used in some of the major ore mining subcategories. This document consists of seve n volumes, discussing the following types of ore extraction and processing (EPA Pub lication Number in parenthesis):

• 

### Vo lume 1: Lead-Zinc (EPA 530-R-94-011);

• 

### Vo lume 2: Gold (EPA 530-R-94-013);

• 

### Vo lume 3: Iron (EPA 530-R-94-030);

• 

### Vo lume 4: Copper (EPA 530-R-94-031);

• 

### Vo lume 5: Uranium (EPA 530-R-94-032);

• 

### Vo lume 6: Gold Placer (EPA 530-R-94-035); and

• 

### V olume 7: Phosphate and Molybdenite (EPA 530-R-94-034).

Other useful descriptions of or e 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. (Mar ch). Chantilly, VA. DCN
07219.Section 4.0 – Regulatory Framew ork for Ore Mining Discharges



### 4-1 4 .0 R EGULATORY 

### F RAMEWORK FOR 

### O RE 

### M INING 

### D ISCHARGES



### Under Section 304(b) of the Clean Water Ac t (CWA), EPA first promulgated Ore Mining and Dressing Point Source Category Effluent Li mitation Guidelines (ELGs), (40 CFR Part 440) on December 3, 1982, (47 FR 54609) to set national technology-based pollutant limits for wastewater discharges from or e 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, me rcury, nickel, and zinc; as well as meeting BPT limits for total suspe nded solids and pH. Certai n facilities in some subcategories must also meet the New Source Performance Standards (NSPS) of no discharge except in areas where net precipitation (precipi tation 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 pro cess wastewater; and may or may
not include stormwater runoff (U.S. EPA, 1996).

EPA has authorized state agencies to admi nister the NPDES program in all but New Mexico, Idaho, Massachusetts, New Hampshire, and Washington D.C. For these States, some Tribal Lands, some federal faci lities, and U.S. Territories, EP A 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 wa stewater 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 with in 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 c onditions, stream flow, ecology, and other factors such as any Total Maximum Daily Load (TMDL) developed forSection 4.0 – Regulatory Framew ork 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 Wat er 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 litig ation 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 c overed under individual or general NPDES industrial wastewater permits based on 40 CFR Part 440. Some stormwater runoff at mines may be controlled under indivi dual or general NPDES industrial wastewater permits based on 40 CFR Part 440, and other stor mwater runoff at mines may be controlled under individual or general NPDES stormwater permits.

In jurisdictions that EPA has not aut horized to implement the NPDES program, stormwater discharges are subjec t to Sector G of EPA’s Multisect or General Permit for Industrial Activities (MSGP) developed to implement Ph ase I Stormwater Regulations (40 CFR Part 122.26). Authorized states have developed thei r own general stormwater permits for mining discharges that conform to the MSGP.

Figure 4-1 illustrates the process used to dete rmine the regulatory classification of discharges from ore mining operations, which de pends on whether a discharge is process water or stormwater, and whether the water is mana ged by commingling with other wastewaters or individually conveyed to discharge point.

EPA’s MSGP, and some state general stor mwater permits, include requirements to conduct benchmark monitoring and develop Best Management Pr actices (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 le vels to determine whether existing BMPs are sufficient. If benchmark concentrations are exceeded, the facility must augment existing BMPs and continue sampling stormwater. However, if po llutant concentrations are consistently below benchmark concentrations, the facility may ceas e 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 le ss 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 me tals concentrations, ei ght states require less frequent sampling than specified by the Fede ral MSGP; and two stat es require no routine sampling at all. Only one state, Washington, requ ires more stringent stormwater monitoring than
the federal MSGP.

3 Table G-4 of the MSGP lists the wa stewaters from mining activities covered by Part 440 versus the MSGP, as specified in an October 2000 Federal Regi ster Notice: runoff from waste rock an d 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 Framew ork for Ore Mining Discharges



### Figure 4-1. Example of Discha rge Classification Depending on Wastewater Source and Management (U.S. EPA, 2003)

4-3Section 4.0 – Regulatory Framew ork for Ore Mining Discharges



### 4-4 Table 4-1 compares MSGP benchmark monitoring re quirements with those in stormwater general permits issued by authorized stat es with significant ore mining operations.

4. 3 Distinction Between Technology-Based P ermit Limits and Water Quality-Based
Permit Limits

If a facility applies for an individual NPDES permit, the pe rmit writer is required to first derive facility-specific Technology-Based Effl uent 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 WQ BELS, and apply the more stringent of the two limits in the permit in order to ensure attainme nt 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 perm it writer must also determin e the water qual ity-based waste load allocation for the discharge.

4.4 Ore Mining Regulatory Framework References

1. U .S. EPA. 1982. Development Document for Ef fluent 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 th e Ore Mining and Dressing Point Source Category Gold Placer Mine Subcate gory. 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 for Ore Mining Discharges4-5Table 4-1. Comparison of Monitoring Requirements forWestern States and Federal General Stormwater PermitsPermitaMonitoring RequirementsAnalytes to be Monitored

TSS TDS Turbidity pH Hardness Metals b Sulfates COD Nitrogen (NO 3 +NO 2 )WashingtonPermittee must monitor discharges four times per year until concentrations below benchmarksare measured foreight quarters.99992008 FederalMSGP (coversIdaho and NewMexicoc)Permittee must monitor discharges four times peryear in the first yearof permit coverage. Ifpollutant concentrations exceed benchmark values, then the permittee must implementadditional BMPs to remedy the situation and continue to monitor four times per year untilmeasured concentrations are below benchmark values.99999CaliforniaPermittee must monitordischarges three times per year.99MontanaPermittee must monitor discharges at least twice per year until all concentrations are belowbenchmarks for three consecutive sampling events.99999ArizonadPermittee must monitor at least once during the first year of coverage. If pollutantconcentrations exceed benchmark values, thenpermittee must implement additional BMPs toremedy the situation and must continue to monitor twice per year until measuredconcentrations are below benchmark values.99999UtahCopper mining and dressing facilities must monitor their discharges four times per year forCOD, TSS, and nitrate plus nitrite nitrogen during years 2 and 4 of permit coverage. Norequirements for other types of mines.999NevadaPermittee must monitor discharges once per year; alternatively, the permittee may submit astatement that these discharges will not cause exceedances of applicable WQS.999999WyomingPermittee must monitor discharges once per year.999South DakotaExcept for coal pile runoff, monitoring is not required on a routine basis.eColoradoMonitoring is not required on a routine basis.eSource: 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 StormwaterPollution Prevention Plan is suspected or to measure the effectiveness of BMPs.Section 5.0 – Review of TM DL Studies to Determine the Extent to Which Ore Mines May Be a Cause of Water Quality Impairments



### 5-1 5.0 R EVIEW OF 

### TMDL S TUDIES TO 

### D ETERMINE THE 

### E XTENT TO 

### W HICH 

### O RE 

### M INES 

### M AY 

### B E A 

### C AUSE OF 

### W ATER 

### Q UALITY 

### I MPAIRMENTS



### Under CWA Section 303(d) NPDES authorized st ates, 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 author ities submit to EPA for approval, identifies sources of impairment and specifies the maxi mum 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 ar e stored electronically and available for keyword searching on EPA’s Waters 4 

### website. The representati veness 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 stormwat er sources of water quality impairment.

EP A’s review of TMDL studies identifie d many instances where past ore mining operations impaired surface water quality. Howeve r, 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 t ypes 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 rele vant 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, Ne vada, 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 mi ning 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 watershe d were removed from further analysis,
which reduced the number of studies for further review from 158 to 42.

2. EPA determined whether the studies iden tified 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 documen ts 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 TM DL 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 desc ribed 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 wi ll commonly close and re-open pe riodically 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 discussi on of recently closed mines.
EPA reviewed in detail the relevant informati on 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.

Fo r 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 Impl ementation 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. A DEQ, 2005. French Gulch TMDLs for Cadmium, Copper, and Zinc: Headwaters to Hassayampa River

.

5. E PA, 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 OreMines May Be a Cause of Water Quality Impairments5-3Table 5-1. TMDL Studies with Informationon Active and Recently Closed Ore MinesaTMDL StudyParametersAssociated withImpairmentActive and Recently ClosedMinesbSummary of Data AvailableAdditional CommentsPinto Creek,Pinto Creek, AZCu•Gibson Mine (closed)•BHP Pinto Creek Mine (active)•Carlota Copper Project (active)Appendix A (data and figures) is not includedin the available TMDL report; some data areprovided in the text of the report.The partial data that were availabledid not clearly identify documentedsurface water impacts from the activemines.French Gulch,Hassayampa River, AZCd, Cu, Zn•Zonia Mine (closed)Document includes extensive in-streammonitoring data for metals and load estimatesfor all stream segments.No data documented that the ZoniaMine discharges led to streamimpairment.Pena Blanca,Pena Blanca Lake, AZHg•St. Patrick Mine (closed)Study provides concentration data fromsediment and fish tissue samples and someconcentration data from water column samplesThe TMDL study identified other pastmining projects and currentexploratory projects, but it does notprovide information on their relativepotential mercury loads.Red River,Rio Grande toHeadwaters. NewMexicoAl, turbidity,and sediment•Molycorp Questa Mine (active)Document includes in-stream monitoring datafor aluminum, benthic macroinvertebrates,stream flow, turbidity, and TSS; it does notprovide data for any mine sites.None.Bryant Creek,Doud Springs, NVAs, Cu, Fe, Ni,temperature,turbidity, TSS•Leviathan Mine (closed)Document includes statistical summary ofstream flow, arsenic, iron, turbidity, and TSSmeasurements in creek. No data are providedfor mine sites.Although mining impacts arereferenced throughout the TMDLdocument, the study describes onlythe Leviathan Mine.Lower SimilkameenRiver,Oroville, WAAs•Similco Mine (active)•Dankoe Mine (active)•Corona Nickel Plate Mine(active)•Cadorado Mine (active)•(All in Canada)Document includes in-stream monitoring datafor arsenic. No data are provided for minesites.The TMDL study acknowledges thatactive mining occurs in the U.S.portion of the Similkameenwatershed, but it does not specificallymention any mine sites in the U.S.Trinity River,Trinity River Basin, CASediment•Deiner Mine (closed)•La Grange (closed)Study estimates sediment loads from majorsources.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 TM DL 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.

1 0. 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 P ROCESS 

### W ATER 

### D ISCHARGES



### Table 6-1 summarizes annual discharge esti mates 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 con centration values that appeared
to be outliers inconsistent with other data. EPA found that reporting errors had occurred in several cases and that actual discharge concentr ation values were signifi cantly lower. EPA made adjustments to data based on in formation provided by facilities.

Th e data in Table 6-1 were taken from EPA’s DMRLoads2007 Database, which contains discharge data primarily for “major” facilities. Da ta for facilities classified as “minor” are not required to be reported at the national level, a lthough 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):

• 

### To xic pollutant potential;

• 

### Di scharge flow to stream flow ratio;

• 

### Co nventional pollu tant 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 Corpor ation 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 396Section 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 S TORMWATER 

### A NALYSIS



### 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 no t adequately representative to support any national or regional
conclusions about stormw ater discharges from ore mines (ERG, 2010a).

EPA Region 9 provided stormw ater monitoring data for ei ght 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 thes e 17 facilities, from the Minnesota Pollution Control Agency. However, EPA determined that all but one of the Minnesota stormwater discharges covered by the Minneso ta DMRs were commingled with process water discharges, so that no discharge data were available for segreg ated 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 Ta ble 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.

B ased on the information presented in Appendi x B, the following states have at least ten permitted discharges regulated by general stormwater permits (number of permitted discharges in parentheses):

• 

### A rizona (31);

• 

### Al aska (25);

• 

### Montana (15);

• 

### Wyoming (12);

• 

### Idaho (13);

• 

### California (11);

• 

### Colorado (10); and

• 

### Nevada (10).

In addition to searching for available stor mwater data, EPA also observed stormwater controls at three Arizona coppe r mines during site visits in September 2009, to better understand stormwater management at ore mines. Detailed in formation on the facilities that EPA visited is included in the site visit report (ERG, 2010b).

7 .1 Quality Procedures Used to Create Analysis Spreadsheets

E PA entered stormwater monitoring data in to 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 concen trations where QA issues (e.g., holding time exceedances, insufficient sample volume) were indicated in the DMR.

For metals, EPA considered “total” and “t otal 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 pollu tant concentrations, but it does not affect any other elements of the statistical analysis.

E PA verified that all data to be used we re 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 reporte d were general stormwater permit IDs.

• 

### For the Minnesota data, EPA reviewed th e outfall descriptions provided in the NPDES permit applications. EPA did not an alyze these data because none of the outfalls with monitoring data were pu rely stormwater (based on outfall descriptions).

• 

### For the Montana data, EPA verified that e ach of the outfalls was classified with an “R” code in Envirofacts, indica ting that it was a stormwater outfall.

EPA also compared stormwater pollutant concentrations to daily maximum limits specified in Subpart J of the Or e Mining Effluent Guidelines (Copper, Lead, Zinc, Gold, Silver, and Molybdenum Ores Subcategory) 5 

### and benchmark concentra tions specified in the 2008 Multi-Sector General Permit (MSGP) for i ndustrial 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 wa ter), 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 ParametersFlowMetalspHTSSCODHardnessTurbidityN (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 concentra tions 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 Guidelin es. 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
Exceedin g

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 spr eadsheet database, and us ed 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 ParametersFlowMetalspHTSSCODHardnessTurbidityN (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 Stor mwater 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. Monitori ng data did not includ e mercury measurements. b – Daily Maximum from Subpart J. * – The benchmark values of some metals are depe ndent 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.

O f 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 c oncentrations in the Montana stormwater data are 2,200 and 200 mg/L, respectively.

Although the average concentrations of copper, lead, a nd 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

D ue to the limited scope of the data that EP A 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 stor mwater 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 monito ring data summarized in this chapter, EPA
concludes:

• 

### St ormwater 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 concentra tions were consistently higher in the monitoring data from Arizona.Section 7.0 – Stormwater Analysis



### 7-7 • 

### TS S 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 measurem ents 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 mon itoring data consiste ntly 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 C oncentrations in Ariz ona and Montana Ore Mining Stormwater Discharges. April 27, 2010.

2. ERG. 2010b. Site Visit Repor t: Arizona Copper Mines. (March). Chantilly, VA. DCN
07219.

3. U.S. EPA. 1998. Memorandum from William Te lliard to Pat Sosinski (Region 3) Re:
Total vs. Total Recoverable Metals. Engineering and Anal ysis Division. Washington,
DC.

4. U.S. EPA. 2010. Envirofacts Da tabase. Available online at www.epa.gov/enviro . Date accessed: 27 January, 2010.

5. U .S. EPA, 2008. Multi-Sector General Permit For St ormwater Discharges Associated With Industrial Activity (MSGP). Washington, DC (September). Available online at: http://cfpub.epa.gov/npd es/stormwater/msgp.cfm . Date accessed: 27 January, 2010.Section 8.0 – High Density Sludg e Treatment Technology Review



### 8-1 8. 0 H IGH 

### D ENSITY 

### S LUDGE 

### T REATMENT 

### T ECHNOLOGY 

### R EVIEW



### During the course of the Ore Mining Prelimin ary 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 perm it writers when considering mine wastewater
treatment systems.

8.1 Background of High Density Sludge Recycling

Th e 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 wastew aters containing high concentrations of dissolved metals. EPA identified one facility, the Leadvi lle Mine District Tunnel, which uses the HDS process to treat alkaline wa stewater with high concentra tions of dissolved metals.

Th e 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):

• 

### M etal finishing (electro-p lating and galvanizing);

• 

### Ch emical manufacturing (i .e. pigment plants);

• 

### Sm elting/refining;

• 

### Co al preparation;

• 

### Metal molding and casting; and

• 

### Site remediation of heavy metals.

One benefit of the HDS proce ss is that sludge storage and disposal costs can be much lower than traditional sludge-gen erating treatment because the process generates a denser sludge. Sludge storage and disposal costs can often ex ceed the initial capital costs of conventional treatment plants over the life of their operation. Rather than di sposing 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 creat e a denser, more compact sludge, lowering the total sludge volume (Leon and Zick, 1997).

P art of the reason that the HDS process produc es a denser sludge is that the recycling process creates metal compounds with a lower affi nity for water. Tradit ional sludge-generating treatment systems treating metal-bearing wastewaters remove metals by forming metal hydroxides that bond with water molecules, prod ucing wetter, less conc entrated 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 conven tional lime-based treatment systems and the HDS process, conventional systems can generall y be converted via small equipment additionsSection 8.0 – High Density Sludg e Treatment Technology Review



### (e.g., small tanks, mixers, pumps, meters). Howeve r, 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 a dd the alkali (e.g., lime, sodium hydroxide) directly to the influent wastew ater, most HDS systems mix the al kali 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)

T he 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 a dd to the system based on differences between a pre-determined pH set point and the constant pH measurements taken
in the neutralization tank. Becau se of each metal’s optimum so lubility for precipitation and treatment system efficiency, the pH set point is specific to the wastew ater being treated. The specific pH is determined to optimize metals re moval and alkali addition rates. In some cases, HDS systems also have the advantage of using le ss alkali to remove the same amount of metals compared to conventional treatment systems, becau se the recycled sludge creates additional sites for metal ions to form complexes (thereby in creasing 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 sy stem. 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 us e the HDS process to treat wastewater from mining sites (facility location in parenthe ses). Most of the sites iden tified below are not active mine sites and many are undergoing remediation.Section 8.0 – High Density Sludg e Treatment Technology Review



### 8-3 • 

### Asarco Primary Lead Smelter (East Helena, MT) – According to the Superfund Five-Year Review for this s ite, 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 M ontana Department of Environmental Quality, the facility treats mine water usi ng 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 Sup erfund 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 st udy says that the system removes over 99 percent of the copper, zinc, and cadmi um in the mine drainage (U.S. EPA, 2006).

• 

### Le adville Superfund Site (Leadville, CO) – The Leadville Superfund site
includes the Leadville Mine Draina ge 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).

• 

### Me ttiki Coal Mine (Oakland, MD) – An article prepared by Mettiki Coal Company mentions that the Mettiki Coal Mi ne 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 seep age. The FEIS includes estimates of effluent water quality based on similar treatment systems (U.S. EPA, 2003a).Section 8.0 – High Density Sludg e Treatment Technology Review



### 8-4 8.4 Permit Requirements and Level of T reatment Required for the HDS System

EPA obtained permits for four of the eight facilities lis ted 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 or ders 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 cu rrently 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 Treatment Technology Review8-5Table 8-1. Permit Limits for HDS Systems Treating Discharges Associated with Ore Mining (Units are in mg/L)PollutantaLowest Concentration Set by ELGsbButte Resources(ID: MT0000191)Teck-Pogo(ID:AK0053341)Red Dog Mine(ID: AK0038652)Leadville Tunnel(ID: CO0021717)ApplicableSubpartscMonthlyAvg.DailyMax.MonthlyAvg.DailyMax.MonthlyAvg.DailyMax.MonthlyAvg.DailyMax.MonthlyAvg.d,eDailyMax.d,eCadmiumF,G,H,J,K0.050.10.00350.00520.000110.000220.0020.00340.00090.0012CopperF,G,H,J,K0.150.30.010.0150.00220.00450.01510.04370.0230.023LeadF,G,H,J,K0.30.60.0110.0170.00060.00110.00810.01960.00150.032MercuryD,J,K0.0010.0020.000050.0000750.000010.000020.000010.000020.00013NLZincC,E,F,G,H,J,K0.510.1580.2380.02140.04290.11960.25730.0840.329Source: 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: MercuryE: TitaniumF: TungstenG: NickelH: Vanadium (mined alone - not as a byproduct)J: Copper, Lead, Zinc, Gold, Silver, and MolybdenumK: Platinumc – 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 Sludg e Treatment Technology Review



### 8-6 8 .5 Observations about HDS

B ased on information cited in this section, EPA made the following general observations
about HDS.

• 

### Co nventional lime-softening systems can be converted to HDS systems via small equipment additions (e.g., tanks, pumps, meters);

• 

### Wh ile conventional lime treatment syst ems produce sludge containing between 1 to 3 percent solids, HDS systems ge nerally produce sludge between 25 and 35 percent solids;

• 

### Use of the HDS system results in lowe r sludge storage and disposal costs;

• 

### The HDS system provides for better re moval of certain metals (e.g., cadmium, zinc) in some cases than a conve ntional lime precipitation system;

• 

### In some cases, it may be possible to econom ically recover metals from the dense sludge produced by the HDS process; and

• 

### The four HDS systems for which EPA obtai ned a permit were discharging treated effluent with cadmium, copper, lead, and me rcury 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 Conf erence with Janelle Ortiz, Bureau of
Reclamation.

5. Leon, M. and R. Zick. 1997. Dense Sludge Pr ocess for Reduced AMD Sludge Disposal. Prepared by Chester Engineers, Pitts burgh, Pennsylvania. Available online at: http://wvmdtaskforce.com/pr oceedings/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/serv ices/environmental_sustainable/highdensity-sludge-hds-process.htm . Date Accessed: August 10, 2009.

8. South Florida Water Management Distri ct. 1998. UEC Water Supply Plan Support

Document

9. U.S. EPA, 1983. Treatability Manual – Volu me I. Treatability Data. Washington, DC.Section 8.0 – High Density Sludg e Treatment Technology Review



### 8-7 10. U.S. EPA, 1983. Treatability Manual – Volu me 1II. Technologies. Washington, DC.

11. U.S. EPA. 1998. Environmental Protection Agen cy Authorization to Discharge Under the National Pollutant Discharge Eliminati on System AK0038652 – Red Dog Mine. DCN
05537.

12. U.S. EPA. 1999. Five-Year Review: East Hele na Smelter Superfund Site (NPL Site No. 30). Prepared by U.S. EPA Region 8, Helena, MT.

13. U.S. EPA. 2002. Technical Support Projec t: Technical Session Summary. Prepared by U.S. EPA. Denver, Colorado.

14. U.S. EPA. 2003a. Final Envi ronmental Impact Statement – Pogo Gold Mine Project. Prepared by U.S. EPA Re gion 10, Seattle, WA.

15. U.S. EPA. 2003b. EPA and Hardrock Mini ng: A Source Book for Industry in the Northwest and Alaska Appendix E: Wastewat er Management. Prepared by U.S. EPA Region 10, Seattle, WA.

16. U.S. EPA. 2004. Environmental Protection Ag ency. 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 Re d Dog Mine Extension – Aqqaluk Project SEIS. Prepared by U.S. EP A Region 10, Seattle, WA.

19. U.S. EPA. 2008. Environmental Protection Agen cy Authorization to Discharge Under the National Pollutant Discharge Elimination Sy stem CO0021717 – Leadville Mine Drainage
Tunnel.

### Appendix A

NUMERIC LIMITS SPECIFIED IN THE ORE MINING EFFLUENT GUIDELINESAppendix AA-1Table A-1. Monthly Average Limits from Effluent Guidelines for Ore Mining OperationsSubpartOre TypeDischarge SourcesELG LevelRequired ParametersaAlAsCdCuFeFe(diss.)HgNiPbRaRaUZnCODNH3pH(S.U.)SettleableSolids(mL/L)TSSAIron OreMine Drainage and MillsBPT/BAT/NSPS—————1—————————6 to 9—20BAluminum OreMine DrainageBPT/BAT/NSPSb1———0.5——————————6 to 9—20CUranium, Radium, andVanadium OresMine DrainageBPT/BAT/NSPSc—————————10320.5100—6 to 9—20Mills using acid or alkalineleachBPT—0.5———————103—0.55001006 to 9—20DMercury OreMine DrainageBPT/BAT/NSPSd——————00.1———————6 to 9—20MillsBPT/BAT/NSPSNoDischargeeETitanium OreMine Drainage (Lode Deposits)BPT/BAT/NSPSf————1——————————6 to 9—20MillsBPT/BAT/NSPSg————————————0.5——6 to 9—20Mine Drainage (Dredge Mines)BPT/BAT/NSPSh————1——————————6 to 9—20FTungsten OreMine Drainage and MillsBPT/BAT/NSPSi—0.50.050.15————0.3———0.5——6 to 9—20GNickel Ore SubcategoryMine Drainage and MillsBPTj—0.50.050.15————0.3———0.5——6 to 9—20HVanadium OreMine Drainage and MillsBPTk—0.50.050.15————0.3———0.5——6 to 9—20IAntimony OreMine Drainage and MillsN/ANo limits promulgated.JCopper, Lead, Zinc, Gold,and Silver OresMine DrainageBPT/BAT/NSPSl——0.050.15——0—0.3———0.75——6 to 9—20Froth Flotation MillsBPT/BAT/NSPSm——0.050.15——0—0.3———0.5——6 to 9—20Copper OresLeach processesBPT/BAT/NSPSNoDischargeeGold and Silver OresCyanide millsBPT/BAT/NSPSNo DischargeeMolybdenumMinedrainageBPT/BAT/NSPSn—0.50.050.15——0—0.3———0.5——6 to 9—20Mill DischargesBPT/BATo—0.50.050.15——0—0.3———0.5——6 to 9—20KPlatinum OresMine DrainageBAT——0.050.15——0—0.3———0.75—————Mill DischargesBAT——0.050.15——0—0.3———0.5—————MGold Ores (Placer Mining)Process Water DischargesBPT/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 andevaporation for the drainage area may be discharged subject to the limitations for minedrainage.Appendix AA-2f – 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 and50 mg/L for monthly average and daily max., respectively). Lead is not regulated in milldischarges. BAT regulates Cd, Cu, and Zn only.NSPS regulates Cd, Cu, Zn, pH, and TSS only.i – For mines producing less than 5,000 tonnes per year, only TSS and pH are regulated. TSS limits are less stringent (30 and 50 mg/L for monthly average and daily max., respectively). Lead is not regulated in milldischarges.j – For mines producing less than 5,000 tonnes per year, only TSS and pH are regulated in the mine drainage, and mill discharges are not regulated. TSS limits are less stringent(30 and 50 mg/L for monthly average and dailymax., 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 activitiesm – For mines producing less than 5,000 tonnes per year, only TSS and pH are regulated under BPT. TSS limits are less stringent(30 and 50 mg/L for monthly average and daily max., respectively). BPT does not regulateHg. BAT does not regulate As, pH and TSS. NSPS does not regulate As.n – For mills processing less than 5,000 tonnes per year, only TSS and pH are regulated under BPT. TSS limits are less stringent (30 and 50 mg/L for monthly average and daily max., respectively). BPT does not regulate Hg.BAT does not regulate As, pH and TSS. NSPS does not regulate As.Under NSPS, no discharges are allowed from froth flotation mills.o – Limit is for instantaneous max.Appendix AA-3Table A-2. Daily Maximum Limits from Effluent Guidelines for Ore Mining OperationsSubpartOre TypeDischarge SourcesELG LevelRequired ParametersaAlAsCdCuFeFe(diss.)HgNiPbRaRaUZnCODNH3pH(S.U.)SettleableSolids(mL/L)TSSAIron OreMine Drainage and MillsBPT/BAT/NSPS—————2—————————6 to 9—30BAluminum OreMine DrainageBPT/BAT/NSPSb2———1——————————6 to 9—30CUranium, Radium, andVanadium OresMine DrainageBPT/BAT/NSPSc—————————301041200—6 to 9—30Mills using acid or alkaline leachBPT—1———————3010—1——6 to 9—30DMercury OreMine DrainageBPT/BAT/NSPSd——————00.2———————6 to 9—30MillsBPT/BAT/NSPSNoDischargeeETitanium OreMine Drainage (Lode Deposits)BPT/BAT/NSPSf————2——————————6 to 9—30MillsBPT/BAT/NSPSg————————————1——6 to 9—30Mine Drainage (Dredge Mines)BPT/BAT/NSPSh————2——————————6 to 9—30FTungsten OreMine Drainage and MillsBPT/BAT/NSPSi—10.10.3————0.6———1——6 to 9—30GNickel Ore SubcategoryMine Drainage and MillsBPTj—10.10.3————0.6———1——6 to 9—30HVanadium OreMine Drainage and MillsBPTk—10.10.3————0.6———1——6 to 9—30IAntimony OreMine Drainage and MillsN/ANo limits promulgated.JCopper, Lead, Zinc, Gold,and Silver OresMine DrainageBPT/BAT/NSPSl——0.10.3——0—0.6———1.5——6 to 9—30Froth Flotation MillsBPT/BAT/NSPSm——0.10.3——0—0.6———1——6 to 9—30Copper OresLeach processesBPT/BAT/NSPSNoDischargeeGold and Silver OresCyanide millsBPT/BAT/NSPSNo DischargeeMolybdenumMinedrainageBPT/BAT/NSPSn—10.10.3——0—0.6———1——6 to 9—30Mill DischargesBPT/BATo—10.10.3——0—0.6———1——6 to 9—30KPlatinum OresMine DrainageBAT——0.10.3——0—0.6———1.5—————Mill DischargesBAT——0.10.3——0—0.6———1—————MGold Ores (Placer Mining)Process Water DischargesBPT/BAT/NSPS————————————————0.215—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 andevaporation for the drainage area may be discharged subject to the limitations for minedrainage.f – BAT regulates Fe only.Appendix AA-4g – 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 and50 mg/L for monthly average and daily max., respectively). Lead is not regulated in milldischarges. BAT regulates Cd, Cu, and Zn only.NSPS regulates Cd, Cu, Zn, pH, and TSS only.i – For mines producing less than 5,000 tonnes per year, only TSS and pH are regulated. TSS limits are less stringent (30 and 50 mg/L for monthly average and daily max., respectively). Lead is not regulated in milldischarges.j – For mines producing less than 5,000 tonnes per year, only TSS and pH are regulated in the mine drainage, and mill discharges are not regulated. TSS limits are less stringent(30 and 50 mg/L for monthly average and dailymax., 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 activitiesm – For mines producing less than 5,000 tonnes per year, only TSS and pH are regulated under BPT. TSS limits are less stringent(30 and 50 mg/L for monthly average and daily max., respectively). BPT does not regulateHg. BAT does not regulate As, pH and TSS. NSPS does not regulate As.n – For mills processing less than 5,000 tonnes per year, only TSS and pH are regulated under BPT. TSS limits are less stringent (30 and 50 mg/L for monthly average and daily max., respectively). BPT does not regulate Hg.BAT does not regulate As, pH and TSS. NSPS does not regulate As.Under NSPS, no discharges are allowed from froth flotation mills.o – Limit is for instantaneous max.

### Appendix B

SUMMARY OF PERMITTED DISCHARGES COVERED BY THE ORE MINING
POINT SOURCE CATEGORYAppendix 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 Mini ng 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.