Mining Methods (continued)

• Solution Mining– Put a chemical solution into the ground to

leach resources out

– Solution reacts with ore and liquid is removed pulling resource with it

– Used in salt mines

• Placer Mining– Sift through material in riverbeds to gather

loose pieces of resource

– gold

Mining Methods (continued)

• Undersea Mining

– Dredging vacuum cleaner to collect sand and gravel from sea floor

– Diamonds, copper, silver

– Expensive to access

– Hydrothermal vents heat dissolves metals and cold water crystallizes the material

Processing Minerals and Metals

• Remove ore from the ground• Processing happens at the mining site• Transporting is expensive and wasteful• Breakdown ore crushed into correct particle

sizes• Separate ore

– Froth flotation – mix ore and water into a slurry– Chemicals and air added– Minerals become hydrophobic (don’t react with

water) and attract to air bubbles– Minerals float to the top with the air bubbles– froth flotation– froth flotation 2

• Once separated, 2 products remain– Mineral

– Waste product (tailings)

• Concentrated minerals get shipped to metal production plants– Smelting melt down metals to combine with

other metals or chemicals

– Create alloys with characteristics of several metals

– Smelting

– smelting 2

Negative Impacts of Mining

• Increased Erosion

– Disturb large areas of land by removing plants, which speeds up erosion

– May take a long time for plant life to return since soil will have lost a lot of nutrients

• Clogged Waterways

– Increased sediment and particles because rocks are displaced during mining

– Habitats may become flooded

– Rocks can block sunlight from aquatic plants

Negative Impacts• Water Pollution

– Large amounts of rock exposed to air– Forms sulfuric acid and acid rain– Acid drainage acid and metal leach from rock

and seep into groundwater– Toxic to wildlife, water unsuitable for drinking– acid drainage– acid drainage 2

• Air Pollution– Wind disperses tiny particles into air– Miners can inhale toxic fumes and coal dust

causes black lung disease

• Undersea Mining– Disruption of the sea floor destroys habitats and

organisms– Metals can get into water and enter food chain– negative impacts

Social Impacts

• Causes property damage

– Cracks in foundation

– Forests lost

– Tunnels collapse – produce sinkholes

• Job opportunities and money brought into poor areas

Mining Regulations

• General Mining Law of 1872

– Due to the Gold Rush

– Manages and promotes mining

– Governs mining metallic minerals

– Prohibits mining national parks

– Stake claim to mine on public land

• Lease land from government and claim rights to minerals

• Don’t pay any part of profit to government

• Patent claim and land becomes privately owned• General Mining Law

• Mineral Leasing Act of 1920– Governs the mining of fossil fuels on public land– Must pay annual rental fees to rent land– Pay royalties on products extracted

• Amending the General Mining Law– Hardrock Mining and Reclamation Act

• Ends the patenting process• Miners pay government 4% of profit from existing mines

and 8% of profit from new mines– Money goes towards environmental cleanup and

reimbursement to communities affected by mining

• More public land set aside not to be mined• Tells mining companies how to fix land and reduce water

pollution

Surface Mining Control and Reclamation Act

• Companies must reclaim, or restore, land after mining is complete

• Post bonds to cover costs of reclamation in case company doesn’t restore land

• Must remove structures

• Replace soil and rocks, fill in holes, and plant vegetation

Mining Safety

• Established ventilation requirements

• Still accidents so improvements need to be made

Responsible Mineral Use

• New technologies make some minerals more in demand

• Cell phones have tantalum

• Recycle cell phones for the

minerals

– Decreases energy use and saves

money