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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 session state of alaska and u s environmental protection agency

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
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
Mining Life Cycle
  • Exploration
  • Development
  • Operations
  • Closure
  • Post-closure
module overview
Module Overview
  • Minerals Exploration
  • Mining Fundamentals
    • Types of mining
    • Types of mineral processing
    • Mining waste products and their management
terms and definitions
Terms and Definitions
  • Mineral
  • Ore or orebody
  • Waste
how do you find mineral deposits
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
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
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
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
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
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 exploration mostly conducted under generally allowed uses
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
Airborne Geophysics
  • Magnetics
  • Electromagnetics
  • Radiometrics
  • Gravity
mid stage exploration usually requires hard rock exploration permit
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
advanced stage exploration may require more land use permits
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
slide23

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
  • 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
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

Resources and Reserves

The more you know,

the less you have

(sort of)

evolution of knowledge
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
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
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
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
Resources to Reserves

Modifying Factors – mining, metallurgical, economic, legal,

environmental, social and governmental factors

Increasing knowledge

resources and reserves35
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
what is a mine
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
How are ores mined?
  • Open pit mining
  • Underground mining
  • Strip mining
  • Placer mining
what is mineral processing
What is mineral processing?
  • Production of valuable metal from the mined ore
how are metals produced from the 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
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)
flotation
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
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.
separation of metal from leach solution
Separation of Metal from Leach Solution
  • Carbon Adsorption: Separates the gold-cyanide complex via carbon.
  • Electrowinning: Uses steel wool or copper as a cathode to extract the metal
  • Precipitation: Solution is combined with chemicals to form metal precipitate
production of metal
Production of Metal
  • Smelting
  • Refining
slide54

Gold Mining & Processing

Ore Body

Surface Mining

Underground Mining

Mining

drilling

stoping

blasting

draw

loading

haulage

Waste

Waste

hauling

hoisting

…to dump

Ore

…to dump

crushing

grinding

Tailings

Concentrate

flotation

…to tailings pond

slide55

Concentrate

Gold Processing

leaching

carbon adsorption

Loaded

carbon

leachate

Spent carbon –

reactivation

carbon stripping

Stripping

solution

Electrowinning

Refined Gold

tailings disposal
Tailings Disposal
  • Tailings dam and pond
  • Dry stack disposal
  • Paste disposal
  • Backfilling in pits and underground mine openings
greens creek mine
Greens Creek Mine

Tailings Dry Stack

Water Treatment Plant

Lined Pond

Truck Wash