U.S. Environmental Protection Agency Abandoned Mine Lands Team Reference Notebook September 2004 DDDDDiiiiisssssccccclllllaaaaaiiiiimmmmmeeeeerrrrr The policies and procedures set forth herein are intended as guidance for employees of the U.S. Environmental Protection Agency. They do not constitute rulemakings by the Agency and may not be relied on to create a substantive or procedural right enforceable by any person. The Government may take action that is at variance with the policies and procedures in this reference document. This is a living document and may be revised periodically without public notice. Nothing in this document constitutes a regulatory determination nor does the use of definitions reflect official Agency policy. Front Cover Photos, top to bottom: Lower retention pond at Libby Asbestos Mine, Libby, Montana; Rocks stained by acid mine drainage in Squaw Creek, Mammoth Mine, California; Mine tailings piles in residential areas of Eureka, Utah. Reference Notebook Table of Contents Chapter 1 • Introduction ......................................................................................................................... 1 Chapter 2 • Background ......................................................................................................................... 3 Chapter 3 • EPA’s Abandoned Mine Lands Programs ....................................................................... 17 Chapter 4 • Coordinating with Federal AML Programs .................................................................... 29 Chapter 5 • State AML Programs ........................................................................................................ 39 Chapter 6 • Reuse and Redevelopment of AML ................................................................................ 53 Glossary ................................................................................................................................................... 63 Acronyms ................................................................................................................................................. 69 References............................................................................................................................................... 73 Table 2-1 • Selected AML Inventory Estimates Table 2-2 • Reclamation Costs Per State Table 4-1 • Federal Regulatory & Programmatic Authorities for Cleaning Up AML Table 4-2 • Bureau of Land Management (BLM) AML Sites Funded for FY01 Table 4-3 • National Park Service (NPS) AML Reclamation Site Summaries Table 4-4 • USDA Forest Service AML Reclamation Site Summaries Table 5-1 • State Requirements for Hardrock Mine Sites Table 5-2 • State and Tribal AML Programs and Inventory Resources Appendix A • CERCLIS and EPA Regional AML Inventory Appendix B • Other Non-Federal AML Data Resources Appendix C • Current Information on Mine Waste Treatment Technologies Appendix D • Programs and Organizations Involved in AML Reclamation i This page intentionally left blank. Reference Notebook 1 Chapter IIIIInnnnntttttrrrrroooooddddduuuuuccccctttttiiiiiooooonnnnn This reference document is intended to illustrate the extent of the abandoned mine lands (AML) contamination problems across the U.S. and the range of actions that EPA’s AML Team intends to take in addressing this problem. Its aim is to provide assis- tance to EPA staff in better coordinating their AML functions. The policies and procedures set forth herein are intended as guidance for employees of the U.S. Environmental Protection Agency. They do not constitute rulemakings by the Agency and may not be relied on to create a substantive or procedural right enforceable by any person. The Government may take action that is at variance with the policies and procedures in this reference document. This is a living document and may be revised periodically without public notice. Nothing in this document constitutes a regulatory determination nor does the Waste rock pile and warning sign at Mammoth use of definitions reflect official Agency policy. Mine, California. This document is divided into six parts: • Chapter 1, an introduction to EPA’s AML Team; • Chapter 2, an overview of the cause and extent of the AML problem; • Chapter 3, an overview of EPA’s AML Programs; • Chapter 4, a summary of federal AML Programs; • Chapter 5, a review of state AML Programs; and • Chapter 6, a look at AML site reuse and redevelopment. As this document provides an overview of many topics, numer- ous appendices and tables supplement the text by offering a deeper examination of individual chapter components. 1.1The Scope of Abandoned Mine Lands As a first step in understanding the AML problem, the AML Team created the following scope: “Abandoned mine lands” are those lands, waters, and surrounding watersheds contaminated or scarred 1 Reference Notebook by the extraction, beneficiation or processing of ores and minerals (excluding coal). Abandoned mine lands include areas where mining or processing activity is determined to be temporarily inactive. For purposes of this reference This scope is intended to focus the AML Team on the chemical and physical contamination problems at hardrock mines. Al- document, “abandoned mine though this scope does not specifically state it, mining opera- lands” are those lands, waters, and tions associated with coal, oil, natural gas, gravel, sand, and surrounding watersheds contami- stone are not included as abandoned mine lands. However, nated or scarred by the extraction, mining sites associated with phosphate extraction are included beneficiation or processing of ores as abandoned mine lands, even though they are categorized as "leasable minerals" in the glossary. and minerals (excluding coal). Abandoned mine lands include areas where mining or processing 1.2 Role of EPA’s Abandoned Mine LandsTeam activity is determined to be tempo- rarily inactive. EPA’s AML Team has been created to provide EPA Headquar- ters and regions access to expertise on issues at abandoned mine sites. The team is a subgroup to the already existing EPA National Mining Team (NMT) and will address issues related to abandoned mine sites. The AML Team will also serve as a focal point for coordinating and facilitating EPA policy, funding, process, and technical issues with stakehold- ers such as, but not limited to, National Mining Association, Mineral Policy Center, Bureau of Land Management (BLM), U.S. Department of Agriculture (USDA) Forest Service, West- ern Governors Association (WGA), states, tribes, and others on abandoned/inactive mine research, characterization, cleanup, and redevelopment activities. A goal of the AML Team is to set priorities for the evaluation, cleanup, and redevelopment of abandoned mine sites to reduce federal government financial liabilities in addressing these sites. This group has also been established to identify and resolve key EPA technical and policy issues at abandoned mine sites to promote a nationally consistent and fiscally sound decision-making process for AML sites across the country. In addition, the AML Team will work to identify opportunities to prevent future AML problems in active mining operations. This team will work with and support existing Office of Superfund Remediation and Technology Innovation (OSRTI) teams and national teams (e.g., remedy selection, sediments, National Mining team). The AML Team is composed of regional and Headquarters technical and policy staff from EPA’s Office of Enforcement, OSRTI, Office of Solid Waste (OSW), and Office of Radiation and Indoor Air (ORIA). For more information on EPA’s Abandoned Mine Lands Pro- gram, visit: http://www.epa.gov/superfund/programs/aml. 2 Reference Notebook 2 Chapter BBBBBaaaaaccccckkkkkgggggrrrrrooooouuuuunnnnnddddd To set the stage for discussing the problems associated with abandoned mines, this document will first present how ore and mineral extraction and beneficiation of specific minerals and metals occurs. The nature and extent of the abandoned mine lands problem is discussed, followed by a general overview of the estimated costs of addressing the problem. 2.1The Processes of Hard Rock Mining Metals are mined from two basic types of deposits, lode and placer deposits. Lode deposits are concentrated mineral deposits in solid rock. Iron, copper, lead, gold, silver, and zinc are mined mainly from lode deposits. Placer deposits are alluvial deposits of sand, gravel, and rock, containing valuable metals. They usually contain metals that were once part of a lode deposit. Only a small percentage of domestic gold and silver is derived from placer deposits. Metal mining processes include extraction and beneficiation. Extraction removes the ore from the ground; beneficiation concen- trates the metal in the ore by removing unwanted constituents. 2.1.1 Mining and Ore Extraction Most ore-bearing rock lies beneath unwanted “overburden.” Accessing the ore may be as environmentally destructive as the beneficiation and processing of the ore. 3 Reference Notebook The following describes three basic approaches to mining/ extracting ore: • Surface or open-pit mining, which requires blasting rock, soil movement, and vegetation removal to reach lode deposits. Open pit mining is the primary domestic source of iron, copper, gold, and silver. Open pit mining was also once the principal means of uranium mineral extraction. • Underground mining entails sinking a shaft to reach the main body of ore. Underground mines do not create the volume of overburden waste associated with surface mining. Lead, antimony, and zinc mining are solely underground operations in the U.S. • Solution or fluid mining entails drilling into intact rock and using chemical solutions to dissolve lode deposits. During solution mining, the leaching solution, usually a dilute acid, penetrates the ore and dissolves soluble metals. This pregnant leach solution is then retrieved Historical mine portal at Elizabeth Mine, Strafford, Vermont. for recovery at a solvent extraction and electrowinning plant. This method of mining is used to recover copper, gold, and uranium. 2.1.2 Beneficiation Beneficiation is the process of concentrating or enriching ores. Under regulations promulgated pursuant to the Resource Conservation and Recovery Act (RCRA) , (40 CFR §261.4) beneficiation of ores and minerals is defined as including the following activities: crushing, grinding, washing, dissolution, crystallization, filtration, sorting, sizing, drying, sintering, smelting, pelletizing, briquetting, calcining to remove water and/or carbon dioxide, roasting, autoclaving, and/or chlorination in preparation for leaching, gravity concentration, magnetic separation, electrostatic separation, flotation, ion exchange, solvent extraction, electrowinning, precipitation, amalgamation, and heap, dump, vat, tank and in situ leaching. Some of the more commonly used practices of beneficiation include the following: • MMMMMiiiiilllllllllliiiiinnnnnggggg extracts ore to produce uniform-sized particles using crushing and grinding processes. • MMMMMaaaaagggggnnnnneeeeetttttiiiiiccccc ssssseeeeepppppaaaaarrrrraaaaatttttiiiiiooooonnnnn is used to sort magnetically susceptible minerals from gangue minerals by applying a magnetic field. Iron ores are commonly separated this way. • FFFFFllllloooootttttaaaaatttttiiiiiooooonnnnn uses a chemical reagent to make minerals adhere to air bubbles for collection. • GGGGGrrrrraaaaavvvvviiiiitttttyyyyy cccccooooonnnnnccccceeeeennnnntttttrrrrraaaaatttttiiiiiooooonnnnn separates minerals based on differences in their gravity. 4 Reference Notebook • TTTTThhhhhiiiiiccccckkkkkeeeeennnnniiiiinnnnnggggg/////fffffiiiiilllllttttteeeeerrrrriiiiinnnnnggggg removes most of the liquid from slurried concentrates and mill tailings. • LLLLLeeeeeaaaaaccccchhhhhiiiiinnnnnggggg is the process of extracting a soluble metallic compound from an ore by selectively dissolving it in a solvent such as water, sulfuric or hydrochloric acid, or cyanide solution. The desired metal is then removed from the “pregnant” leach solution by chemical precipi- tation or another chemical or electrochemical process. Leaching methods include dump, heap, and tank opera- tions. • SSSSSmmmmmeeeeellllltttttiiiiinnnnnggggg requires melting down the metallic ore concentrate, and the metal is separated from other substances in the concentrate. • EEEEEllllleeeeeccccctttttrrrrrooooowwwwwiiiiinnnnnnnnnniiiiinnnnnggggg mixes a metal-bearing solution with chemicals that transfer the metal to a more concentrated solution called an electrolyte. The electrolyte is pumped to steel tanks. Starter sheets hang in the solution and, using an electric current, the metal is plated from the electrolyte onto the sheet, forming purer metal on the plates. 2.1.3 Mineral Specific Operations The following summaries describe the extraction and beneficiation processes used for mineral-specific mining operations and the associated wastes generated during these processes: • IIIIIrrrrrooooonnnnn ore is almost exclusively surface mined. Typical beneficiation steps applied to iron ore include: milling, washing, sorting, sizing, magnetic separation, flotation, and agglomerations. Milling followed by magnetic separation is the most common beneficiation sequence used, according to the American Iron Ore Association. Agglomeration generates byproducts such as carbon dioxide, sulfur compounds, chlorides, and fluorides. Primary wastes are overburden/waste rock and tailings. • CCCCCoooooppppppppppeeeeerrrrr is generally extracted from surface, under- ground, and increasingly, from in situ operations (the practice of percolating dilute sulfuric acid through ore to Former copper leachate collection, extract copper). Beneficiation of copper consists of concentration, and electrowinning operations at crushing and grinding; washing; filtration; sorting and Anaconda Mine, Yerington, Nevada. sizing; gravity concentration; flotation; chlorination; dump and in situ leaching; ion exchange; solvent extraction; electrowinning; and precipitation. The methods vary according to the particular copper ore characteristics and economic factors. Approximately half of copper beneficiation occurs through dump leaching, while the other half uses flotation. Typical leaching agents include hydrochloric and sulfuric acids. 5 Reference Notebook Solvent extraction requires impure leach solutions containing copper, iron, and other base-metal ions to be mixed with an active organic extractant, usually kero- sene, forming a copper-organic complex. Primary wastes include overburden/waste rock, tailings, spent ore and spent or escaped leach solutions. • LLLLLeeeeeaaaaaddddd and zzzzziiiiinnnnnccccc, which are typically found together in common ores, are extracted from underground opera- Mining operations are per- tions. Beneficiation of lead and zinc includes crushing formed throughout the U.S., but and grinding; filtration; sizing; flotation; and sintering of concentrates. Flotation is the most common method for the concentration of metal concentrating lead-zinc minerals. Lead-zinc ores are mining is in the western region conditioned to prepare for flotation; common condition- of the country. ers include lime, soda ash, caustic soda, or sulfuric acid. Reagents used in the flotation processes typically include sulfur dioxide, zinc sulfate, coal tar, copper sulfate, and sodium or calcium cyanide. Primary wastes consist of overburden/waste rock and tailings. • GGGGGooooolllllddddd and sssssiiiiilllllvvvvveeeeerrrrr, also typically found together in com- mon ores, are extracted from surface, underground, and in situ (experimental) operations. Beneficiation consists of three principal techniques: cyanide leaching, flotation of base metal ores followed by smelting, and gravity concentration. Cyanide leaching generated 88 percent of all domestic lode gold in 1991. Over half of the silver produced in 1991 was from smelting concentrates produced by flotation. Gravity concentration is used primarily for gold and silver placer deposits. Primary wastes include overburden/waste rock, spent process solutions, tailings, slag, and spent ore. • UUUUUrrrrraaaaannnnniiiiiuuuuummmmm has been extracted from surface, under- ground, and in situ operations, and quite commonly produced along with either precious metals, copper, vanadium, or phosphate from the same geologic de- posit. The mining of uranium ores by both underground and surface methods produces large amounts of bulk waste material, including bore hole drill cuttings, exca- vated top soil, barren overburden rock, weakly uranium- enriched waste rock, and subgrade ores (or protore). At some abandoned mine sites, ore enriched with uranium was left on site when prices fell, while transfer stations at some distance from remote mines may contain residual radioactive soil and rock without any visible facilities to mark their location. Beneficiation enrichment of ores and chemical processing to yield “yellowcake” takes place at mills, which place their finely ground waste rock byproducts in tailings impoundments. In situ operations have moved the chemical processing steps from the mill to plants at the solution well field site and directed spent leachate solutions and produced 6