Potential Environmental Potential Environmental ProblemsProblems

A. Mining operation itselfA. Mining operation itself– Disposal of a large amount of rock and Disposal of a large amount of rock and

wastewaste– NoiseNoise– DustDust

BeneficiationBeneficiation Smelting and refiningSmelting and refining

From Underground MiningFrom Underground Mining

SubsidenceSubsidence– Block/cavingBlock/caving– Room and pillarRoom and pillar– Salt miningSalt mining

Subsidence in rancher’s Subsidence in rancher’s fieldfield

Subsidence from Pb-Zn Subsidence from Pb-Zn miningmining

From UndergroundFrom Underground

Acid Mine DrainageAcid Mine Drainage– FeS minerals in coalFeS minerals in coal– Sulphide depositsSulphide deposits– Acidic streams can pick up heavy Acidic streams can pick up heavy

elements and transport themelements and transport them

Rock that has acid forming Rock that has acid forming materialmaterial

DrainageDrainage

Acid and open pitsAcid and open pits

Berkley Pit

Other problems with open Other problems with open pitspits

Very large holesVery large holes Pit slopes steep and not stable. Pit slopes steep and not stable.

Cannot be maintainedCannot be maintained May fill with water May fill with water Strip coal mines –loss of top soil in Strip coal mines –loss of top soil in

pastpast– Now smoothed out and top soil addedNow smoothed out and top soil added

Disposal of Waste RockDisposal of Waste Rock

More problematic for open pit than More problematic for open pit than undergroundunderground

Waste rock piles have steep angle of Waste rock piles have steep angle of repose and thus may not be stablerepose and thus may not be stable

Bingham in its hay day produced Bingham in its hay day produced 400,000 tons of waste rock per DAY!400,000 tons of waste rock per DAY!

Tailings pondsTailings ponds

From concentrating usually have From concentrating usually have high pHhigh pH– At Bingham acid waters mixed with At Bingham acid waters mixed with

tailings water to neutralizetailings water to neutralize Different metals have different Different metals have different

problemsproblems

Problems with Problems with Smelting/RoastingSmelting/Roasting

Air: SOAir: SO22 and CO and CO22 and particulate and particulate mattermatter

Noranda Quebec used to have the Noranda Quebec used to have the highest single point source of SOhighest single point source of SO22 in in the world. It may have been the world. It may have been surpassed.surpassed.

CN (Au); NaOH and F (Al); solvents CN (Au); NaOH and F (Al); solvents (electrotwinning); heavy metals; oil (electrotwinning); heavy metals; oil and greaseand grease

Environmental ImpactEnvironmental Impact

Environmental impactEnvironmental impact– From mineral exploration and testingFrom mineral exploration and testing– From mineral miningFrom mineral mining– From mineral resources refiningFrom mineral resources refining– From mining waste disposalFrom mining waste disposal

Environment Impact of Mineral Environment Impact of Mineral DevelopmentDevelopment

The impact depends upon many factors:The impact depends upon many factors:– Mining proceduresMining procedures– Hydrologic conditionsHydrologic conditions– Climate factorsClimate factors– Types of rocks and soilsTypes of rocks and soils– TopographyTopography

Also population: NIMBYAlso population: NIMBY

Impact of Mineral Exploration and Impact of Mineral Exploration and TestingTesting

Mineral exploration and testingMineral exploration and testing– Surface mapping, geochemical, Surface mapping, geochemical,

geophysical, and remote-sensing data geophysical, and remote-sensing data collectioncollection

– Test drillingTest drilling ImpactImpact

– Generally minimal impactGenerally minimal impact– More planning and care needed for More planning and care needed for

sensitive areas (arid, wetlands, and sensitive areas (arid, wetlands, and permafrost areas)permafrost areas)

General impactGeneral impactDirect impact on land, water, air, and Direct impact on land, water, air, and

biological environmentbiological environment Indirect impact on the environment: Indirect impact on the environment:

Topographic effect, transportation of Topographic effect, transportation of materials, etc.materials, etc.

Impact on social environment: Impact on social environment: Increased demands for housing and Increased demands for housing and servicesservices

Impact of Mineral Impact of Mineral ExtractionExtraction

and Processing (1)and Processing (1)

Impact of Mineral ExtractionImpact of Mineral Extractionand Processing (2)and Processing (2)

Impact from mining operationsImpact from mining operations– Land disturbances; e.g., Land disturbances; e.g., – Waste from mines: 40% of the mining area for waste Waste from mines: 40% of the mining area for waste

disposal, mining waste 40% of all solid wastes; e.g., disposal, mining waste 40% of all solid wastes; e.g., , ,

– Special mining, e.g., chemical leaching from gold Special mining, e.g., chemical leaching from gold mining; e.g., mining; e.g.,

– Mining acid drainage, during mining and post-mining; Mining acid drainage, during mining and post-mining; e.g., New World districte.g., New World district

Berkeley Pit.kmz

ASARCO tailings.kmzChico placer.kmz

Golden Sunlight.kmz

Mclaren tailings.kmz

Impact of Mineral ExtractionImpact of Mineral Extractionand Processing (4) and Processing (4)

Water pollutionWater pollution– Trace elements leaching out into water, Trace elements leaching out into water,

such as Cd, Co, Cu, Pb, Mo, Znsuch as Cd, Co, Cu, Pb, Mo, Zn– Flooding of abandoned mines, oxidation Flooding of abandoned mines, oxidation

of sulfide ores = sulfuric acidof sulfide ores = sulfuric acid– Acid mine drainage from tailingsAcid mine drainage from tailings

Pollution of water from Pollution of water from miningmining

Minimizing the Impact of Minimizing the Impact of Mining (1)Mining (1)

Knowledge and technology transfer: developed Knowledge and technology transfer: developed countries to developing countriescountries to developing countries

Environmental Regulations: Environmental Regulations: Forbid bad Forbid bad mining practices, Clean Air Act, and on- and mining practices, Clean Air Act, and on- and offsite treatment of wastesoffsite treatment of wastes

Land reclamation: Land reclamation: AAbout 50% of land used in bout 50% of land used in mining industry reclaimedmining industry reclaimed

Use of new biotechnology in mining: Use of new biotechnology in mining: Bio-Bio-oxidation, bioleaching, biosorption, genetic oxidation, bioleaching, biosorption, genetic engineeringengineering

Figure 14.14Figure 14.14

Minimizing the Impact of Minimizing the Impact of Mining (2)Mining (2)

Recycling Mineral Resources Recycling Mineral Resources (1)(1)

Why recycle? Consider the impact of the Why recycle? Consider the impact of the wasteswastes– Toxic to humansToxic to humans– Dangerous to natural ecosystemsDangerous to natural ecosystems– Degradation of air, water, and soilDegradation of air, water, and soil– Use of land for disposalUse of land for disposal– Aesthetically undesirableAesthetically undesirable

Waste contains recyclable materials Waste contains recyclable materials Saves energy, money, land, raw mineral Saves energy, money, land, raw mineral

resources from more miningresources from more miningSaves energy and money when Saves energy and money when

recycling instead of refining raw ore recycling instead of refining raw ore materialsmaterials

Recycling has been proven to be Recycling has been proven to be profitable and workableprofitable and workable

Recycling Mineral Recycling Mineral Resources (2)Resources (2)

Most-recycled metals: Iron and steel, Most-recycled metals: Iron and steel, 90% by weight90% by weight

One-third as much energy needed to One-third as much energy needed to produce steel from recycled scrap as produce steel from recycled scrap as from original orefrom original ore

More than $40 billion produced from More than $40 billion produced from recycled metals in 1998recycled metals in 1998

Other recycled metals: Lead (63%), Other recycled metals: Lead (63%), aluminum (38%), and copper (36%)aluminum (38%), and copper (36%)

Recycling Mineral Resources Recycling Mineral Resources (3)(3)

Life cycle of a metal Life cycle of a metal resourceresource

Sustainability: long-term strategy for Sustainability: long-term strategy for consuming the resourcesconsuming the resources

Find an alternative material for the Find an alternative material for the metal, e.g., glass fiber cable for copper metal, e.g., glass fiber cable for copper wireswires

Use raw materials more efficientlyUse raw materials more efficientlyMore R&D on innovative substitutes or More R&D on innovative substitutes or

ways to keep the R/C ratio, a solution to ways to keep the R/C ratio, a solution to the depletion of nonrenewable the depletion of nonrenewable resourcesresources

Minerals and SustainabilityMinerals and Sustainability

Considering the fact that mineral resources are Considering the fact that mineral resources are nonrenewable, do you believe that technology nonrenewable, do you believe that technology will eventually help to meet the growing demand will eventually help to meet the growing demand for mineral resources? If yes, explain.for mineral resources? If yes, explain.

Biotechnology shows the potential for cleaner Biotechnology shows the potential for cleaner minerals extraction and waste disposal. Will minerals extraction and waste disposal. Will biotechnology bring about any environmental biotechnology bring about any environmental problems?problems?

What types of environmental impact would occur What types of environmental impact would occur ififwe increasingly extract more mineral resources we increasingly extract more mineral resources from the seafloor?from the seafloor?

Applied and Critical Thinking Applied and Critical Thinking TopicsTopics