EARTH SCIENCE Q4 Part 2

Mining

described as the extraction of valuable resources from the Earth for use by society.

• commodities include gold, iron, coal, diamond, sand, and gravel, and fluid resources like oil, and natural gas.

Lion Cavern

(in Swaziland) the oldest mine, dating back 40,000 years, where there is evidence of digging for hematite, an essential iron ore used as red dye

Hematite

an essential iron ore used as red dye

Resource

refers to the entire amount of any particular geologic material of possible economic importance, whether discovered or not

• can be measured physically by mining or drilling (demonstrated, measured, or indicated)

• simply estimated based on reasonably geologic hypothesis and statistical modelling (inferred, hypothetical, speculative, resources)

• The size of a nonrenewable resource does not change over time: it is a fixed and theoretically determinable figure.

Reserve

is a resource that has been inferred with some degree of centainty and may be mined for a profit.

• It’s size can alter over time depending on circumstances such as mining or if a commodity is too expensive to mine.

Metallic Ores

frequently associated with igneous rocks, particularly their hydrothermal fluids.

They can form through contact metamorphic deposits, hydrothermal veins, disseminated ores, submarine hot springs.

Crystal Setting

happens when early forming minerals crystallize and settle to the bottom of a cooling mass of magma.

Layered instructions

(With ultramafic to mafic compositions)
can host deposits of copper, nickel, platinum, palladium, rhodium, and chronium.

Bushveld Complex

a single intrusion in South Africa known as the source of the vast majority, of the world’s chromium commodity

Stillwater Complex

another massive Precambrian still in Montana, USA, similar but lower-grade deposits.

Kimberlite Pipe

a volcanic conduit that transports ultramafic lava from the mantle to the surface - a unique magmatic phenomenon

Diamonds

forms at extreme deep temperatures and pressures, get carried by a Kimberlite pipe to locations where they can be mined.

The Archean Eon

is responsible for known deposits

Hydrothermal Fluids

occurs when a heated solution rich in metals and silica seeps into the country rock, forming ore deposits.

• the most important source of metallic ore deposits

• Majority are metallic sulfides frequently associated with quartz

Four types of Hydrothermal ore deposits

• contact metamorphic deposits

• hydrothermal veins

• dispersed deposits

• hot springs deposits.

Contact metamorphism

can create ores of iron, tungsten, copper, lead, zinc silver, and other metals in country rock

Hydrothermal Veins

are thin deposits that occur along fractures and faults

Chemical precipitation

the most common source of iron and manganese ores

Placer deposits

usually found on streams and beaches: with concentrated heavy sediment grains such as gold nuggets, native platinum, diamonds, and other gemstones.

Supergene enrichment

formed from weathering and downward-moving groundwater; copper and chalcopyrite are the common commodities.

Surface mining and Underground mining

are two principal methods of extracting solid resources

The Commodity’s price and The Cost of the technology

the mining process and its feasibility are determined by

Surface Mining

a method of extracting ore minerals from the earth’s surface

• soil and rock are removed through blasting

Blasting

a controlled use of explosives

Open pit mining

(Type of Surface Mining)

• The mine pit is formed by explosive blasting and drillings

• Targets shallow, widely disperesed minerals

• Pit: a large hole; the most common type of surface mining

Strip Mining

(Type of Surface Mining)

used to mine commodities that cover large and layered resources such as coal

Dredging and placer mining

(Type of Surface Mining)

the mining of materials from the bottom of bodies of water such as rivers, lakes, and seas

• Gold and Diamond - most commonly acquired by this

Underground Mining

another type of mining technique

• used for extracting higher-grade, more localized, or highly concentrated minerals

• To access a mineral, a mining shaft tunnel or a network of these shafts and tunnels is often dug

• South Africa’s deepest mines reach depths of 1,500 - 2,500 meters

Dynamites

are used to blast openings are creates hazardous fumes

Mineral processing

the process of extracting minerals from ore refining them and preparing them for use

Sampling

(Key steps in mineral processing)

the taking of a section that represents a whole that is required for the analysis of this material

Analysis

(Key steps in mineral processing)

this is critical to determine the valuable component of an ore. Chemical mineral, and particle size analysis are all parts of this

Comminution

(Key steps in mineral processing)

the process of crushing and grinding to separate the precious components of the ore. It starts with crushing the ore and ends with grinding the ores into powder

Concentration

(Key steps in mineral processing)

this includes the extraction of precious minerals from raw sources

Dewatering

(Key steps in mineral processing)

this uses the concentration to transform it to useable minerals. This includes filtration and sedimentation of the suspension, as well as dying of the solids