gsc 1620 chapter 13 mineral and rock resources. mineral resources raw and processed mineral...

GSC 1620 Chapter 13GSC 1620 Chapter 13

Mineral and Rock Resources

Mineral ResourcesMineral Resources Raw and processed mineral resources are an integral

part of our daily lives Examples: gypsum – raw material for drywall; halite –

processed into table salt, used for roadway deicing; quartz – raw material for glass production, processed into a timing mechanism for watches or clocks; sand and gravel – construction industry; the mica family of minerals are even used in cosmetics!

Mineral ResourcesMineral Resources

Mineral/rock resource – any useful or valuable solid inorganic substance extracted from the Earth

Mineral resources can be composed of individual chemical elements (e.g., gold), minerals (e.g., halite – rock salt), or solid mixtures (e.g., sand and gravel)

Background TerminologyBackground Terminology Atom – smallest particle of matter that retains all the

properties of a particular chemical element Element – basic chemical building block of matter;

elements can’t be altered by chemical reactions into other substances and can’t be altered by ordinary physical means into other substances

Visualize atoms as spheres with an average diameter of 0.1 billionth of a meter!

How many chemical elements have been recognized? (see slide)

Currently 118 elements have been verified; 92 recognized as naturally occurring

BackgroundBackground Under what extraordinary physical circumstances can

chemical elements be altered to other substances? Compound – a chemical combination of atoms of two or

more elements; e.g., sodium (Na) and chlorine (Cl) chemically combine to form the compound sodium chloride (NaCl)

Mineral – an inorganic (typically), solid, naturally occurring chemical compound with a specific composition and a repetitive internal structure (see slide)

BackgroundBackground

Ore – metallic resource that can be profitably mined

Do you think profitable mineral resources are widely and uniformly distributed within the Earth?


Mineral resources are not ubiquitous and uniformly distributed – one reason is the nonuniform distribution of chemical elements within the continental crust (see slide)


The formation of ores or mineral reserves requires a single or set of processes that concentrates the commodity of interest into an economically viable deposit

Mineral resource deposit concentration processes can occur at or beneath the surface (review slides)

Enrichment (Concentration)Factor =Concentration of substance in deposit

Average concentration of substance incontinental crust

Typical Enrichment FactorsRequired for Profitable Mining

Mineral Resource Concentration ProcessesMineral Resource Concentration Processes

Surface example: concentration of rock salt via evaporation of a saline water body

Saline water

evaporation

Salt layers

Rock salt from an “evaporite”deposit

Mineral Resource Concentration ProcessesMineral Resource Concentration Processes Subsurface example: hydrothermal deposition

(e.g., deposition of solids from hot water solutions as the solution cools or changes chemistry)

Hydrothermal Mineral Deposits

Hydrothermally Deposited Copper

Hydrothermal vein deposits

Mineral Resource DistributionMineral Resource Distribution

Because of the their differences in geological setting and conditions, countries and geographic regions have an unequal distribution of mineral resources – this has political, economic, social, even military, implications (see slide)

U.S. Mineral Resource Distribution and UseU.S. Mineral Resource Distribution and Use

Although there are fluctuations in consumption patterns, the increasing U.S. population and technological advancement demands an increased amount of mineral resources (see slides)

Trends in U.S. material consumption, 1900-1990

What’s the US population?


Note in the following slide the disproportionate consumption by the U.S. of many of the world’s mineral resources


Further note in the following table the limited projected lifetime of many U.S. mineral reserves

What does this and the previous figure imply about the source (primarily domestic or foreign) of many of the mineral resources consumed in the U.S.? (see slides)


Even though the U.S. must import vast amounts of mineral resources, mining remains an important U.S. industry and mineral resource mining occurs in virtually every state (see slides)


Its consumption patterns and supply problems require that the U.S. and other countries with the same problem seek ways to “extend” its mineral resources

These attempts are classified into five general categories

Mineral Resource Extension MeasuresMineral Resource Extension Measures 1) Develop advancements in resource exploration techniques and

resource formation theories to find new deposits more effectively 2)Seek mineral resources in unconventional places (e.g., seafloor

manganese deposits) 3) Develop more efficient resource extraction and purification

techniques 4) Conserve mineral resources by developing technologically more

effective products (products that perform the desired function with less resource) and recycling materials whenever possible

5) Develop substitutes (e.g., substitution of plastic for certain metal uses)

Mineral Resource Extension MeasuresMineral Resource Extension Measures 1) Develop advancements in resource exploration

techniques and resource formation theories to find new deposits more effectively

Many examples can be discussed Geophysical prospecting – gravity surveys,

magnetometer surveys, radioactivity surveys, electric field surveys; instruments are used to measure these fields at various locations – deviations from the norm are used to infer whether a particular commodity is present (see slide and classroom demonstration)

gravitymeter

Gravity Survey

Mineral Resource Exploration AdvancesMineral Resource Exploration Advances

Geochemical prospecting – sampling and analysis of rock, soil, soil gas, air, water, vegetation or other biota; deviations from norm used to infer whether a particular commodity is present

See slide

(analyzegroundwater)

Chemically analyze soils and vegetation forenrichments of gold

Mineral Resource Exploration AdvancesMineral Resource Exploration Advances Geobotanical Surveys –

examination of plant species distribution (e.g., “copper flower”) and health

Various plant species which thrivein soils highly enriched in metalslike copper


Remote sensing – data acquisition without direct physical contact with the object being studied; methods employed include aerial photography and satellite imagery using visible light and other forms of electromagnetic radiation (e.g., infrared) (see slides)

Satellite Imagery

Dry Season Wet SeasonPossible exposedpluton

~ 1 km

Low-altitudeflying aircraftequipped with special chemicalsensors can mapthe distribution of rocks and minerals since thedifferentcomposition of these substancesabsorb and reflectlight differently.


Advances in mineral deposit formation knowledge include plate tectonic influences on mineral deposit formation and new models of mineral deposit genesis (see slides and classroom discussion)

Plate tectonicconnection?

Seafloor manganese nodules

Distribution of seafloor manganese nodules (black). What’s theprimary reason these haven’t been developed?

The short-term future?

Mineral Resource Extension MeasuresMineral Resource Extension Measures 3) Develop more efficient resource extraction and

purification techniques Significant improvements have been made in mining

extraction equipment (Some South African diamond mines approach two miles depth!) and purification techniques (e.g., smelting) allowing deeper and less enriched deposits to be economically mined

Mineral Resource Extension MeasuresMineral Resource Extension Measures 4) Conserve mineral resources by developing

technologically more effective products (products that perform the desired function with less resource) and recycling materials whenever possible

Provide me an example and also note the following table illustrating U.S. recycling trends for certain metals

Mineral Resource Extension MeasuresMineral Resource Extension Measures 5) Develop substitutes (e.g., substitution of plastic for

certain metal uses)

Examples? Potential disadvantages?

Mineral Resource Extension MeasuresMineral Resource Extension Measures

U.S. government approach: Strategic and Critical Minerals Stockpiling Revision Act of 1979

Provides for emergency stockpiles of 93 materials for national defense purposes (about 80% of which are mineral resources) sufficient to sustain the U.S. military and key industries for three years

Mineral Resource Extension MeasuresMineral Resource Extension Measures

The National Materials and Minerals Policy, Research and Development Act of 1980 further directed the federal government to develop policies to strengthen the nation’s mineral supply position

Mining Activities ImpactsMining Activities Impacts Mining and mineral processing accidents claim more

lives during an average year than agriculture or construction accidents

Underground mines disturb relatively small surface areas; however, once abandoned they’re often prone to collapse (see slide)

Collapse pits

Mining Activities ImpactsMining Activities Impacts

Underground coal mines that have groundwater drain through them are likely to produce acid mine drainage; underground coal mines may develop coal seam fires that are nearly impossible to extinguish – these release toxic gases and increase the chance of surface collapse

Acid Mine Drainage

Underground Coal Mining


Surface mines: strip mines or open-pit mines disturb large surface areas; the waste rock and soil (spoil banks) dumped at the surface disrupts the terrain and is a possible source of air, surface water and groundwater pollution (see slides)

Strip mine spoils banks

Open pit mine, Bingham Canyon, Utah

Manganese strip mine in South Africa


Stricter, more recent (last 30 years) U.S. laws require the land after mining to be restored to its pre-mining condition as closely as possible

This obviously raises mine production costs (see slide)


A) Grading of spoils banks at Indian Head coal strip mine, North Dakota

B) Reclaimed portion of Indian Head mine one year after seeding

A B

Mining Activities ImpactsMining Activities Impacts Mineral processing: tailings (fine-grained waste

materials from crushing and grinding of ore) piled along the processing plant can be sources of air, surface water and groundwater contamination (see slide)


A) Tailings piles near Bingham Canyon mine B) Closer view of tailings piles indicating erosion by water

A B


The chemicals used in ore extraction (e.g., potassium cyanide or mercury for gold extraction) are often environmentally hazardous

In undeveloped countries, unregulated mining releases an estimated 2-5 grams of mercury into the environment for every gram of gold recovered

Source: National Geographic: January, 2009

Source:Smithsonian,February, 2012

Mining Activities ImpactsMining Activities Impacts Incorporation of

“cleaner” ore extraction techniques (see figure) would reduce the production of environmental toxins


Smelting (high-temperature heating) extraction may release toxins (e.g., lead, arsenic, mercury) via the exhaust gases

Toxic exhaust gases from one northern Russia metal smelter have killed virtually all the trees approximately 50 miles downwind!

Michigan’s Mining Future ?

Michigan’s Mining Future ?Growing demand for metals worldwide has renewed interest in Upper Peninsula mining prospects Can a balance be found between the promise of new jobs and the risk of increased pollution?

gsc 1620 chapter 13 mineral and rock resources. mineral resources raw and processed mineral...

Documents

chemical compound

individual chemical

profitable mineral resources

chemical reactions

mineral reserves

concentration of rock

chemical combination

halite rock salt