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Mining Information Session State of Alaska and U.S. Environmental Protection Agency. Alaska Forum on the Environment Anchorage, Alaska February 12, 2008. AFE 2008 Mining Information Session Structure. Module 1: Introduction & Mining Fundamentals Module 2: Environmental Concerns & Issues
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Mining Information SessionState of Alaska and U.S. Environmental Protection Agency Alaska Forum on the Environment Anchorage, Alaska February 12, 2008
AFE 2008 Mining Information Session Structure • Module 1: Introduction & Mining Fundamentals • Module 2: Environmental Concerns & Issues • Module 3: Agencies & Process • Module 4: Regulatory Framework
Mining Life Cycle • Exploration • Development • Operations • Closure • Post-closure
Module Overview • Minerals Exploration • Mining Fundamentals • Types of mining • Types of mineral processing • Mining waste products and their management
Terms and Definitions • Mineral • Ore or orebody • Waste
How do you find mineral deposits? • Exploration: Mineral exploration is the search for and evaluation of mineral deposits which have the potential of becoming orebodies. • Objective: To find economic mineral deposits • Outcome: “Discovery,” or to demonstrate the existence of a mineral deposit that can currently be mined, treated, and marketed at a profit
State & Federal Mining Claims • Mining claims require a “discovery” • Claims are “self-initiated” • State claims can be 40 acres or 160 acres in size; federal are 20 acres • Claims are held through rental fees and assessment work
State Lands • Most state lands are open to mineral entry as the state doctrine is for multiple use • Lands closed to mineral entry are usually legislatively designated areas like parks • Or due to land disposals • The state retains its mineral interest even in disposed lands – creating a split estate • Most western states cannot dispose of mineral interest by federal law
Exploration Process Research Literature Geography Reports Reconnaissance Geological Geophysical Geochemical Select Mineral for Exploration Land Acquisition Staking Lease Permit Exam Target Area Mapping Geochemical/physical surveys Mineral/rock analysis Select deposit for evaluation Allocate funds Road construction Drill site prep Physical Testing Initial drilling Follow-up drilling Define Mineral Deposit Evaluate Complete initial economic and engineering feasibility studies Continue, Abandon, or Postpone Project
Exploration is activity spent searching for mineral deposits • Activity is usually in the bush. • The activities generally have little ground disturbance. • It is more expensive with continued success. • Permits are required once ground disturbing activities occur.
Exploration Activities Little or No Ground Disturbance • Geologic Mapping • Rock, sediment, and soil geochemical sampling • Claims staking • Geophysical surveys (air & ground) • Trenching • Core or Rotary Drilling • Bulk sampling • Resource estimation Ground Disturbing Activities The End of the Exploration Cycle
Early Stage Explorationmostly conducted under Generally Allowed Uses • Regional stream sediment geochemical sampling • Airborne Geophysics • Regional geologic mapping • Prospect mapping and sampling • Soil geochemical sampling • Claims staking
Airborne Geophysics • Magnetics • Electromagnetics • Radiometrics • Gravity
Mid Stage Explorationusually requires Hard Rock Exploration Permit • Non-Systematic drill testing of targets and geologic concepts • Ground geophysics • Large-Scale grid geochemical sampling • Trenching through cover • Detailed geological mapping
District Geologic Mapping
Pits and Soil Sampling with an Auger
Advanced Stage Explorationmay require more land use permits • Grid drilling to develop and measure resources • Bulk sampling and metallurgical studies • Underground sampling • Environmental Baseline studies initiated • Stage I feasibility analysis
2000 ASL Prospective Horizon Drill hole 154 area Lookout Mountain Zone Mineralization A A’ Proposed Drilling 1000 ASL Lookout Lookout Stratigraphy Stratigraphy Hanging Wall Mammoth Zone Mafic Rocks Portal MAIN CROSSCUT Historic Niblack Mine 0 ~ Lookout Stratigraphy ~ Footwall Lookout Footwall ~ -1000 ~ Mafic/Felsic Mafic/Felsic Stratigraphy ~ Stratigraphy ~ Stratigraphy Niblack Fault ~ ~ ~ 0 1000 ~ ~ feet ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 11810000 1180000 1182000 1183000 1184000 ~ ~ Lookout ~ ~ Stratigraphy ?? 1185000 Looking West Niblack Project Proposed Underground Program
Commodity Prices • Commodity prices have a direct effect upon exploration expenditures • There is often a year or two lag in activity following price increases • Alaska has a diversity of mineral commodities • Base and precious metals tend to drive most activity
Types of Permits for Exploration • DEC Camp Permit • Temporary Water Use Permit • Overland Travel Permit • Misc. land use permits for staging areas or camps off claims • Bonds for staging fuel • APMA Hard Rock Exploration land use permit • State bond pool for reclamation
Resources and Reserves The more you know, the less you have (sort of)
Evolution of Knowledge Exploration Results -- Reporting is rather loose and wild Mineral Resources -- Reporting is based on geologic continuity and regular sampling Ore Reserves Economics are applied --
Reporting Standards • The Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves (JORC Code, 2004 edition) originally established in 1989 • Canadian Institute of Mining Standards of Mineral Resources. Incorporated by reference in National Instrument 43-101 – Standards of Disclosure for Mineral Projects effective February 1, 2001 • SEC accepts the standards listed above.
Resources A Mineral Resource is an inventory of mineralization that under realistically assumed technical and economic conditions might become economically extractable. It is the tonnage and grade of in-place minerals. Few economic constraints are applied Sometimes crude economic factors such as a lower “cut-off” grade is applied; this may be referred to as a “Minable Resource”.
Reserves or Ore Reserves • Are that portion of a Resource that can be economically mined. • Require studies to define how close together drill holes or samples should be in the mineral deposit (variography). • Require a feasibility study that shows the ore can be mined at a profit. • Require that the project can be legally permitted.
Resources to Reserves Modifying Factors – mining, metallurgical, economic, legal, environmental, social and governmental factors Increasing knowledge
Resources and Reserves • The Resource doesn’t change once definition drilling has been completed. • The Ore Reserve can change as any of the modifying factors change: • Mining Methods and Costs • Commodity Prices • Metallurgical or Milling Ore Recoveries • Transportation Costs • Energy (Electrical and Fuel) Costs • Labor or Equipment Costs
Valuable minerals are extracted from the ground Examples: Hardrock ores: copper, lead, zinc, gold, silver Coal Phosphate rock, stone What is a mine?
How are ores mined? • Open pit mining • Underground mining • Strip mining • Placer mining
What is mineral processing? • Production of valuable metal from the mined ore
How are metals produced from the ore? • Mineral Processing • Separation of valuable mineral from waste minerals • Production of metal from valuable mineral lead Galena – lead sulfide Sphalerite – zinc sulfide silver mineral processing zinc silver
Mineral Processing Steps • First Stage - Crushing and grinding • Second Stage - concentration or extraction of valuable mineral (ex: flotation, leaching, gravity) • Third Stage- metal produced from the mineral (ex: smelting, refining -usually conducted off-site)
Commonly used for many minerals: copper, lead, zinc, molybdenum, gold, silver Chemicals and water are added to cause mineral particles to adhere preferentially to air bubbles Flotation
Leaching • Can follow flotation or be used on its own. • Commonly used for copper, gold, silver, and uranium. • The process of extracting a metal from an ore or concentrate by selectively dissolving it in a solvent.