Chapter 13: Mineral and Rock Resources Flashcards
Resources
any useful economic commodity, one that also changes with time or context
Reserves
portion of a resource that has been discovered and currently available to be extracted
Sub economic Resources
deposits that have already been found but cannot be extracted profitably
Hypothetical
deposits of a mineral in an area have been discovered and more are expected to be found
Speculative
given certain geological conditions, a mineral deposit is expected to be found in a particular type of area, but no exploration has been done yet
Ore
rock or metallic mineral that is economically worth mining
Concentration factor
the concentration necessary for profitable mining determined as a ratio: concentration factor = concentration of the metal in the ore deposit / the average concentration of the metal in the crust
Where are igneous rocks and magmatic deposits found?
commonly found along plate boundaries (areas with extensive magnetic activity)
Pegmatites
rare, unusually coarse-grained igneous intrusions, that are known to produce single crystals over 10 m long, reflecting a very slow growth rate of the crystal
Chromite and Magnetite
Heavy minerals sink to the bottom of a magma chamber as magma cools and minerals begin to crystallize. Minerals that form this way may concentrate at the bottom of a magma to be mined out later like gold and iron.
Why are Diamonds so rare?
they are only created at very high pressures in the earth’s mantle and then brought up rapidly into the crust
What is kimberlite and how it is formed?
is a kind of igneous rock which diamonds are mined from and forms large pipe-like intrusions that rise up from the mantle
Hydrothermal Ores
copper, lead, zinc, gold, silver, platinum, uranium, sulfur is a common component
How is a hydrothermal deposit formed?
fluids that seep into the cracks of surrounding rock are often super-heated and can leach out minerals and ions from the rocks through which they pass. As the fluids cool, they deposit their minerals, forming the hydrothermal deposit
Sulfides
the ore minerals found in hydrothermal deposits
Where are hydrothermal and igneous rock deposits commonly found?
found in areas with extensive magmatic activity (plate boundaries)
Where do iron ore deposits come primarily from?
banded iron formations - world’s oldest known sedimentary rocks
Banded Iron Formations
ancient deposits that consist of alternating layers of sedimentary rock and iron oxides. Initially formed in the sea, but are now found and mined above ground
What are examples of our primary mineral resources?
salt, magnesium, and potassium: we consume over one billion tons per year
Halite
the mineral salt which is mined from evaporite deposits
Evaporite deposits
salt deposits that form when a body of shallow seawater gets “trapped” and dries up: the water evaporates and a layer of salt is left behind
Gypsum
a mineral used in plaster, drywall, fertilizer, and chalk, another common evaporite minded mineral
Placer Deposits
formed by flowing water, as the water velocity slows down minerals may overtime settle out and accumulate in these regions
What is a famous example of a placer deposit?
Gold Rush in California was a placer deposit of gold draining from the Sierra Nevada mountains
How do enriched ore deposits form?
form when soils are leached of their soluble ions, and the soil becomes more concentrated in what gets left behind (it becomes more concentrated in what is not leached out). This occurs in laterite soils, a soil found in tropical climates that has been leached of everything except for aluminum.
Bauxite
an ore material to which aluminum is minded from, This ore is retrieved from laterite deposits
Strip-mining
the mining process used to retrieve Bauxite which is found near the earths surface
Metamorphic deposits
metamorphic rocks form as a result of rocks facing increasing amount of heat and pressure deep within the earth. Graphite, asbestos, and garnets are formed in and minded from these types of deposits
What are the greatest metal mineral resources consumed in the US?
Iron - used for steel products
Aluminum - mined from bauxite, used in canning and construction industries
Copper - conductor of electricity, the main component in wiring
Zinc - used to coat steel cans to prevent rusting
Precious metals - gold, silver, platinum
Nonmetallic Minerals
1) Sulfur - created as a by-product of mining sulfide minerals, and used by industry to create sulfuric acid
2) Halite, or salt, and gypsum
Mineral supply and demand
supply and demand waxes and wanes depending on economic conditions and politics
US Mineral Production and Consumption
the US consumes over 25% of the worlds silver and lead and roughly 20% of the worlds tin, gypsum, and nickel. The US imports minerals that it already produces in abundance
How to preserve mineral resources?
minerals are nonrenewable resources, to preserve the resources consumption rates need to be reduced. Reducing consumption will keep reserve levels in check and would reduce mining pollution and waste disposal.
Remote Sensing
a mapping technique, similar to radar, used by satellites and airplanes to detect and classify objects on the Earth and in the atmosphere, especially in places that are not easily reached on foot
Marine Mineral Resources
as mineral reserves begin to dwindle, seawater and its deposits are being looked upon to make up for the gap
Conversation of Mineral Resources
alternative to reducing reserve supplies by substituting a more abundant nonmetal for a metal product. Another alternative is recycling reduces waste, mining, and greenhouse gases.
Two categories of surface mining?
open-pit mining and strip mining
Open-pit Mining
-extracts rock either intact or crushed
-practical when the ore is located near the surface
-end product leaves a large hole, which may fill with water, which may then carry pollutants elsewhere
- sulfide minerals in the open pot mine react with oxygen and water to form sulfuric acid as a weathering product, creating acid runoff water
Strip Mining
-commonly used to extract coal
-practical when ore is near the surface and runs in layered seams
-when mining operations are completed, the land is reclaimed and restored to habitable levels
Mineral Processing
to extract a specifc metal from an ore can cause serious environmental problems. Processing involves crushing the ore. Waste minerals from this process are called tailings
Tailings
waste minerals from mineral processing. Weathering of the tailings may produce acid drainage, similar to spoil banks of strip miners, and leach out harmful elements such as uranium, mercury, cadmium, and arsenic, that contaminate groundwaters
heap-leaching
A process where cyanide solutions percolate through the tailing piles to dissolve the gold
Smelting
extracts metal by using heat
Downside of Smelting
the process produces sulfuric acid as a waste product gas, contributing to acid rain
