Housekeeping Items

© 2010 Pearson Education Canada

11Mineral Resources and Mining

PowerPoint® Slides prepared by Stephen Turnbull

Copyright © 2013 Pearson Canada Inc.

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Housekeeping Items

• I am in the process of marking the outlines and will get them back to you as soon as I can.

• Any last-minute outlines to be handed in?

• Any announcements? There are some items in the folder that might be of interest.

• A reminder that the assignment that will be taking the place of the mid-term is due on Thursday.

• The mid-term we would have taken is on the web site for study purposes.

• Today we will finish up forestry and move on to mining and minerals.



Upon successfully completing this chapter you will be able to

• Outline the main types of mineral resources

• Summarize the ways in which mineral resources contribute to our economy and society

• Describe the major methods of mining

• Characterize the environmental and social impacts of mining

• Assess reclamation efforts and mining policy in Canada

• Evaluate ways to encourage sustainable use of mineral resources

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Central Case: Mining for … Cell Phones?

• Cell phones and other high-tech products contain tantalum- Coltan = columbite + tantalum

• The Democratic Republic of the Congo was at war- Since 1998, 5 million died and millions more fled

• Soldiers controlled mining operations and forced farmers and others to work, while taking most of the ore- People entered national parks, killing wildlife and clearing

rainforests- Profits from coltan sales financed the war

• Most tantalum from the Congo goes to China• While haven’t seen it, the film “Blood Diamond” deals with

a similar issue with respect to diamonds.11-4



Earth’s Mineral Resources

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Rocks provide the minerals we use

• Rock = solid aggregation of minerals

• Mineral = naturally occurring solid chemical element or inorganic compound with a crystal structure, a specific chemical composition, and distinct physical properties

- Tantalite consists of oxygen, iron, and manganese and occurs most commonly in pegmatite (a type of igneous rock similar to granite)

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We obtain minerals and metals by mining• Mining = systemic removal of rock, soil, or other

material for the purpose of extracting minerals of economic interest

• Because most minerals are widely spread but in low concentrations, miners and geologists try to locate concentrated sources

• Metal = type of chemical element that typically is shiny, opaque, and malleable, and can conduct heat and electricity

• Most metals are present in ore, a rock in which valuable minerals have been concentrated

• Gangue = waste rock and nonvaluable minerals

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Minerals are everywhere in our products

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We obtain minerals and metals by mining (cont’d)

• Economically valuable metals include copper, iron, lead, gold, and nickel

• Canada is a leading producer of these metals and more, including tantalum

- Tantalite ore is mined, processed into tantalum, and used in electronic devices

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We process metals after mining

• Most minerals must be processed after mining

• After mining the ore, rock is crushed and the metals are isolated by chemical or physical means

- The material is processed (refining) to purify the metal

• Alloy = a metal is mixed, melted, or fused with another metal or nonmetal substance

- Steel is an alloy of iron and carbon

• Smelting = heating ore beyond its melting point then combining it with other metals or chemicals

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We also mine nonmetallic minerals and fuels

• Nonmetallic minerals include sand, gravel, phosphates, limestone, and gemstones

- $7 billion/year of sand and gravel are mined in the U.S.

- Phosphates provide fertilizer

- “Blood diamonds” are mined and sold to fund, prolong, and intensify wars in Angola and other areas

• Substances are mined for fuel

- Uranium for nuclear power

- Coal, petroleum, natural gas are not minerals (they are organic), but they are also extracted from the Earth

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We process metals after mining (cont’d)

• Processing minerals has environmental costs

- Most methods are water- and energy-intensive

• Chemical reactions and heating to extract metals from ores emit air pollution

• Tailings = ore left over after metals have been extracted

- Pollutes soil and water

- They may contain heavy metals or acids (cyanide, sulfuric acid)

- Water evaporates from tailings ponds, which may leach pollutants into the environment

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Mining in National Parks?

Mining and other forms of commercial resource extraction are prohibited by Canada’s National Parks Act. Even so, mining has occurred in or near the boundaries of about half of our national parks (and in some provincial parks), and many administrators still identify mining (and principally acid mine drainage) as a major source of adverse environmental impacts in the parks. Some countries do allow mining in their parks.

•Do you think it would ever be acceptable or advisable to allow mining in our national parks? Why (or why not), and under what conditions?

weighing

the issues

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We also mine nonmetallic minerals and fuels

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The Role of Canadian Mining Corporations

• Though not shown on the global map, Canadian mining companies – amongst the largest in the world – play an aggressive role in seeking out and extracting minerals and oil in Latin American countries , and in Africa. Barrick, Goldcorp, Conquistador, HudBay, Manhattan, Greystone, and others are among the prominent firms.

• To get a sense of some of the ecological and social impacts of their operations, see the “Under Rich Earth” video at the VIU Library and search YouTube under the heading of ‘Canadian mining firms in Latin America.’



We also mine nonmetallic minerals and fuels (cont’d)

• Sand and gravel, the most commonly mined mineral resource, are used as aggregate for road-building fill and construction material, and for concrete

• Canada is leading producer of potash, used in fertilizer for crops

• Asbestos is important in Québec

• Gemstones treasured for rarity and beauty

• Uranium, coal, and other fossil fuels

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Mining Methods and Their Impacts

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Mining methods and their impacts

• Mining is an important industry that provides jobs and revenue

• In 2009, mineral production contributed $32 billion to the Canadian economy

• About 58,000 Canadians employed directly in mining and quarrying in 2008

• The non-fuel mining industry, together with processors and manufacturers of products employed more than 351,000 people

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Strip mining removes surface soil and rock

• Strip mining = layers of soil and rock are removed to expose the resource (practiced in Appalachia to remove coal)

• Overburden = overlying soil and rock that is removed by heavy machinery

- After extraction, each strip is refilled with the overburden

• Used for coal, oil sands, sand, gravel

• Destroys natural communities over large areas and triggers erosion

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Strip mining removes surface soil and rock (cont’d)

• Acid drainage = sulfide minerals form sulfuric acid and flow into waterways

- As the sulfuric acid runs off, it leaches metals from the rocks, many of which are toxic

- This toxic liquid is called leachate

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Subsurface mining takes place in underground tunnels

• Zinc, lead, nickel, tin, gold, diamonds, phosphate, salt, coal

• Deepest mines extend nearly 4 km underground

• The most dangerous form of mining

- Dynamite blasts, collapsed tunnels, toxic fumes and coal dust

• Subsurface mines can affect people years after they close

- Acid drainage, polluted groundwater, sinkholes damage roads and homes, etc.

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Subsurface mining takes place in underground tunnels (cont’d)

• Mine Environment Neutral Drainage (MEND) established in Canada in 1988

- Development of new technologies and approaches to prevent, control, and remediate the effects of acid mine drainage

• Metal Mining Effluent Regulation (MMER) in 2002

- Established limits for cyanide, arsenic, and other hazards

• Effluent = any contaminated liquid

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Open pit mining creates immense holes at the surface

• Used with evenly distributed minerals- Terraced so men and machines can move about

• Copper, iron, gold, diamonds, coal• Quarries = open pits for clay, gravel, sand, stone

(limestone, granite, marble, slate) • Huge amounts of rock are removed to get small

amounts of minerals • Habitat loss, aesthetic degradation, acid drainage

• Abandoned pits fill with toxic water

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Open pit mine in Utah

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Pacer mining uses water to isolate minerals

• Pacer (sometimes placer) mining uses running water, miners sift through material in riverbeds

- Coltan miners in Congo, California’s Gold Rush of 1849, British Columbia in 1858, Klondike in 1896

• Used for gold, gems

• Debris washed into streams makes them uninhabitable for wildlife

• Disturbs stream banks, causes erosion, harms riparian plant communities

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Mountaintop mining reshapes ridges and can fill valleys

• Entire mountaintops are blasted off and the waste is dumped into valleys (valley filling)

• For coal in the Appalachian Mountains of the eastern U.S.

• Economically efficient

• Degrades and destroys vast areas

• Pollutes streams, deforests areas, erosion, mudslides, and flash floods

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BEFORE

AFTER



Mountaintop mining reshapes ridges and can fill valleys (cont’d)

• People living in communities near the sites experience social and health impacts

- Mine blasting cracks foundations and walls

- Floods and rock slides affect properties

- Overloaded coal trucks speed down rural roads

- Coal dust and contaminated water cause illness

- Local politicians do not help

- High-efficiency mining reduces the need for workers

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Solution mining dissolves and extracts resources in place

• Solution mining (in-situ recovery) = resources in a deep deposit are dissolved in a liquid and siphoned out

• Salts, lithium, boron, bromine, potash, copper, uranium

• Less environmental impact than other methods

- Less surface area is disturbed

- Acids, heavy metals, uranium can accidentally leak into groundwater

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Some mining occurs in the ocean• We extract minerals (e.g., magnesium) from seawater

• Some minerals are dredged from the ocean floor

- Sulfur, phosphate, calcium carbonate (for cement), silica (insulation and glass), copper, zinc, silver, gold

• Manganese nodules = small, ball-shaped ores scattered across the ocean floor which contain many minerals

- Mining them is currently uneconomical

• Hydrothermal vents may have gold, silver, zinc

• Mining would destroy habitats and organisms and release toxic metals that could enter the food chain

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Restoring mining sites can be very challenging

• Governments in developed countries require companies to reclaim (restore) surface-mined sites

• In Canada, companies are required to post bonds to cover reclamation costs before mine development is approved

- Some countries (Congo) have no regulations

• Reclamation aims to bring a site to a condition similar to its pre-mining condition

- Remove structures, replace overburden, fill in shafts, and replant vegetation

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Restoration of mined sites• Even on restored sites, impacts

may be severe and long-lasting

• Complex communities are simplified

- Forests, wetlands, etc. are replaced by grasses

• Essential symbioses are eliminated and often not restored

• Water can be reclaimed

- Remove heavy metals

- pH is moderated

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Restoring Mined AreasMining has severe environmental impacts, but restoring mined sites to their pre-mining condition is costly and difficult.

•How much do you think we should require mining companies to restore after a mine is shut down, and what criteria should we use to guide restoration?

•Should we require complete restoration? No restoration?

•What should our priorities be – to minimize water pollution, health impacts, biodiversity loss, soil damage, or other factors?

•Should the amount of restoration we require depend on how much money the company made from the mine?

•Explain your recommendations.

•Also: why aren’t company officials personally liable? If I caused the same damage as an individual, I would be criminally liable.

weighing

the issues

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Toward Sustainable Mineral Use(is there such a thing?)

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Minerals are nonrenewable resources in limited supply• We must recover and recycle our limited supplies

• Once known reserves are mined, minerals will be gone

- For example, indium, used in LCD screens, might only last 32 more years

- Gallium (for solar power) and platinum (fuel cells) are also scarce

• Reserve estimates are uncertain

- New discoveries, technologies, consumption patterns, and recycling affect mineral supplies

- As minerals become scarcer, demand and price rise11-36



Minerals are nonrenewable resources in limited supply (cont’d)

• Dark red bar is the number of years available under today’s economic conditions, orange bars represent technically recoverable if prices rise or new technology is developed

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Several factors affect how long mineral deposits may last• Reserve = that portion of the resource that is economically and

legally mineable using current technologies

• Discovery of new reserves increases known reserves

- Minerals worth $900 billion were discovered in Afghanistan in 2010

• New extraction technologies reach more minerals at less expense

• Changing social and technological dynamics modify demand in unpredictable ways

- Lithium batteries are replacing cadmium-nickel ones

• Changing consumption patterns affect how fast we exploit reserves (e.g., a recession depresses demand)

• Recycling extends the lifetimes of minerals11-38



We can make our mineral use more sustainable

• Recycling addresses:

- Finite supplies

- Environmental damage

• In 2007, 84% of households in Canada had access to curbside recycling

- 80% of our lead from recycled batteries

- Reduces fossil fuels as every tonne of aluminum cans saves 6000 litres of gasoline

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We can recycle metals from e-waste• Electronic waste (e-waste) from computers, printers, cell

phones, etc. is rapidly rising, however not always in the most sustainable conditions

• Recycling keeps hazardous wastes out of landfills while conserving mineral resources

• 1.2 billion cell phones sold each year contain 200 chemicals and precious metals

- Phones can be refurbished and resold or dismantled and their parts reused or recycled

- Only 12% of cell phones are recycled in Canada

• Recycling reduces demand for virgin ores and reduces pressure on ecosystems

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426,000 cell phones – the number retired in the U.S. every day



Conclusion

• We depend on minerals and metals to make the products we use

• Mineral resources are mined by various methods

- Contributing to material wealth

- But causing extensive environmental impact (habitat loss, acid drainage, etc.)

• Restoration and regulations help minimize the environmental and social impacts of mining

- Maximize recycling and sustainable use of minerals

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QUESTION: Review

a) Sedimentary rockb) Mined materialsc) Ored) Smelting

Which of the following is defined as “a mineral or grouping of minerals from which we extract metals”?

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QUESTION: Review

Why are mine tailings dangerous?

a) They pollute soil and water.b) They may contain heavy metals or acids.c) Tailings ponds may leach pollutants into the

environment.d) All of these are reasons tailings are dangerous.

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QUESTION: Review

To strip-mine for coal, what must first be removed?

a) Acid drainageb) Coalc) Overburdend) Ore

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QUESTION: Review

This mining method uses terraces in very deep holes to extract iron and diamonds:

a) Stripb) Placerc) Open pitd) Mountaintop removal

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QUESTION: Review

This mining method cracks foundations and walls and causes floods and rock slides while mining for coal.

a) Stripb) Placerc) Open pitd) Mountaintop removal

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QUESTION: Review

The best ways to use mineral resources sustainably are:

a) Recycling and efficiency b) Larger pit mines and recyclingc) Deeper mines and larger pit minesd) Finding new mines and recycling

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QUESTION: Interpreting Graphs and Data

What can be concluded from this slide?

a) Insect diversity increases with increased sulfates.

b) Insect diversity decreases with increased sulfates.

c) Insect diversity is not related to sulfate concentrations.

d) Sulfates are not related to mining activities.

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