Lecture 29: Mineral Resources

Question 1

What can mineral resources be divided into?

Answer 1

Those that are abundant (>0.1% of the crust) and those that are geochemically scarce (<0.1% of the crust)

Question 2

What are the two primary categories of minerals?

Answer 2

• Metallic minerals

* Non-metallic minerals

Question 3

What are Metallic Minerals?

Answer 3

Those we mine for their constituent metals

Question 4

What are Nonmetallic minerals?

Answer 4

Those that we mine for their chemical or physical properties ie. Sodium chloride

Question 5

What are the four terms geologists use to discuss chemical elements?

Answer 5

• Resource
• Reserve
• Mineral deposits
• Ore deposits

Question 6

What is a Resource?

Answer 6

A naturally occuring accumulation of material in concentrations and amounts that make extraction currently or potentially feasible

Question 7

What is a Reserve?

Answer 7

Resources that can be exploited economically under present conditions

Question 8

What are Mineral Deposits?

Answer 8

Localized concentrations of a resource

Question 9

What are Ore Deposits?

Answer 9

A mineral deposit that can be exploited economically

Question 10

What are the five places mineral deposits are derived from?

Answer 10

• Magmatic concentration of elements
• Hydrothermal concentration of elements
• Weathering and concentration of the resulting residual material in place
• Physical sediment concentration by moving water
• Chemical sedimentary concentration

Question 11

How are all five sources of mineral deposits mined?

Answer 11

As ore deposits

Question 12

What is fractional mineralization?

Answer 12

When minerals begin to crystallize as a function of temperature in a magma chamber as it cools

Question 13

What do the crystals that crystallize out of magma undergo?

Answer 13

Crystal settling to the bottom of the chamber because they are denser than surrounding magma

Question 14

What is crystal flotation?

Answer 14

Where crystal minerals are less dense than the magma

Question 15

What can crystal flotation cause?

Answer 15

Accumulation of an ore

Question 16

What is Filter Pressing?

Answer 16

Where much of the remaining magma moves through a fracture, leaving precipitated crystals behind

Question 17

What do Pegmatites form from?

Answer 17

Granitic, water-rich magma slowly cools

Question 18

What do Pegmatites often contain?

Answer 18

Unusual minerals and high concentrations of rare minerals

Question 19

Why do Pegmatite look the way they do?

Answer 19

Because some of the elements do not fit in the crystal lattice and are concentrated in the last portion of the magma which crystallized as pegmatite

Question 20

What are Kimberlites?

Answer 20

Fragmental volcanic rocks from particularly explosive eruptions

Question 21

What do kimberlites usually contain?

Answer 21

Diamonds

Question 22

What causes Hydrothermal Mineral Deposits?

Answer 22

Circulating groundwater near magma deposits that as the water moves from magma may cool rapidly, boil, or interact with oxygen which reduces the solubility of dissolved metals which precipitate as minerals

Question 23

What are the types of Hydrothermal Deposits?

Answer 23

• Veins
• Stratiform deposits
• Disseminated ores

Question 24

What are veins?

Answer 24

Fractures that have filled with mineral deposits

Question 25

When do Stratiform deposits form?

Answer 25

Form when hydrothermal water escapes to the seafloor and deposits a layer of mineral particles resulting in volcanogenic massive sulfide (VMS) deposits near current and former tectonic boundaries

Question 26

When do Disseminated ores form?

Answer 26

When hydrothermal water soaks through porosity in rocks and deposits mineral particles in pore spaces

Question 27

What is Smelting?

Answer 27

A process used to extract the target metal from a source ore but the metal itself is bound into a mineral

Question 28

What is a Residual Deposit?

Answer 28

When a chemical weathering dissolves components of a rock leaving behind more resistant material that is concentrated and water can go through carrying metal with it

Question 29

Where do Laterites form?

Answer 29

Where rocks are weathered in tropical regions that have high variable and annual precipitation causing high leaching rates

Question 30

What are Placer Deposits?

Answer 30

When water sorts sedimentary particles by size and density and dense minerals are concentrated in sands

Question 31

What are common indicators of placer deposits?

Answer 31

Black sands

Question 32

What is Aggregate?

Answer 32

Supplies of sand, gravel, and clay used for construction in urban areas

Question 33

What causes cement to be formed?

Answer 33

Limestone heated with clay, other silicates and or sulfates

Question 34

What can cement be combined with to make concrete?

Answer 34

Cement can be combined with sand and gravel

Question 35

What are Evaporites?

Answer 35

Chemical sedimentary rocks formed by the evaporation of sea water and sometimes lake water

Question 36

What are important Evaporite minerals?

Answer 36

Gypsum, Halite, and potash

Question 37

What are BIF rich in?

Answer 37

Iron ore deposits

Question 38

What are the physical impacts of mining?

Answer 38

Considerable disruption of the environment occurs, the removed material may be difficult to place, and the removal of plants may increase erosion and add sediment and contaminants to streams

Question 39

What are Mine Tailings?

Answer 39

The byproducts that remain after resources are extracted from a deposit