(TEST 2) Earth Science, Lecture pt 4 (ch 12) Flashcards
What is Halite (NaCL) used for?
It is used as a ground for table salt and it helps to de-ice
roadways in winter
What is diamond (C) used for?
It’s used as a great cutting tool
What is a mineral resource?
It’s a rock, mineral, or element that is important to humans
What is a mineral resource footprint?
The amount of minerals needed to support a lifestyle
What are mineral and rock resources considered to be at the human time scale?
Non-renewable
What do people do to address the issue of supplies being exhausted?
They oppose building new mines near their home
What is ore deposit?
A body of rock or sediment whose concentration of some material is sufficiently high that the deposit is economically feasible to extract
What is an example of ore deposit?
Gold mining
What is a mineral (or ore) reserve?
A deposit that is economical to extract under current conditions
What does high/low grade ore deposit describe?
It describes the enrichment level of the ore deposit
What is the enrichment factor?
The ratio of a resource’s necessary concentration for profitable mining to its average concentration in Earth’s crust
What are some characteristics of diamond (Kimberlite/Lamproite) pipes?
- Forms at depths of 120-200 km in upper mantle
- Brought to the surface by sudden and violent eruptions
- Relatively rare: low-frequency events and not all pipes have diamonds
What are some characteristics of intrusive layered deposits?
- Early-stage magmatic process where crystal settling occurs during cooling of a magma to create layered ore deposits
- Typically contain metallic-rich minerals such as: chromium, titanium, and vanadium
What are some characteristics of hydrothermal deposits?
- Late-stage magmatic process where deposits are concentrated in veins or small dikes.
- Gold and silver prevalent in hydrothermal deposits
- Disseminated deposits
What are the characteristics of disseminated deposits?
- Low-grade deposits where ore minerals are widely dispersed
- Common minerals include: copper, tin, and tungsten
What are the characteristics of massive sulfide deposit?
- Formed along mid-ocean ridges
- Reactions between seawater and basaltic rocks create
hydrothermal fluids rich in copper, lead, and zinc
What are some characteristics associated with regional metamorphism?
- High temperature and pressure associated with deep burial of rocks and tectonic activity
- Can change the mineralogy and texture
- Produces ores of asbestos, talc, graphite, and other non-metallic deposits
What are some characteristics associated with contact metamorphism?
- Intrusion of igneous materials
- Heat, pressure, and chemically active fluids of the cooling magma interact with the country (or host) rock
What are placer deposits?
Streams transport and sort
material according to size and
density in a certain area
What is residual ore?
An accumulation of valuable minerals, formed by the natural removal of undesired constituents of rocks or conversion
What are iron minerals precipitated out of?
Shallow seas
What are branded iron formations?
Alternating layers of quartz
and iron oxide minerals
What are evaporite deposits?
Dissolved material in water precipitate out of solution as the waters evaporate
When do marine deposits form?
When marine basins become isolated by tectonic activity
What are non-marine deposits typically driven by?
Climatic variations
What are the two ways of surface mining?
- Open-pit mine
- Surface mine
What is open-pit mine?
Excavating large volumes of low-grade deposits
What is a strip mine?
Mineral deposits lie parallel to the surface; overburden is
scraped away
Why do we use underground mining?
Used today when removal of overburden is too expensive or
disturbance of surface not allowed
What are some ways of mineral processing?
- Physical separation
- Smelting
- Leaching
What is mine tailing?
Large piles of
non-economical rock and
processed ore
Mineral resources increases as _____ development increases
Economic
What are strategic minerals?
Minerals considered critical by a country but that must be imported in significant quantities
What is the general mining act of 1872?
Prospectors could purchase public lands for $5/acre and then extract the resources without paying any royalties to the government
What is the clean air act of 1970 and clean water act of 1972?
Minimized pollution from modern mining operations
Mining of minerals fueled what revolution?
The industrial revolution
What is acid mine drainage?
It’s the term for the leachate that drains from tailings and underground mines
Why do some acid mine drainage have a blue/greenish color?
It’s due to copper precipitates
Most acid mine drainage contains….?
Dissolved iron
What are some impacts of underground mines?
- They can create a lot of void spaces that can collapse suddenly (also known as sinkholes)
- They can also cause the ground to lower gradually (also known as subsidence)
