Earth final- Mineral resources

Low grade deposit

A deposit in which the mineral content is minimal but still exploitable is called a low grade deposit

High grade deposit

A deposit with high concentration of a desired element is called a high grade deposit

Disseminated deposits

Disseminated (scattered) deposits occur when a multitude of mineralized veinlets develop near or at the top of a large igneous intrusion Probably the most common of these are the porphyry copper deposits, in which the ore minerals are widely distributed throughout a large volume of granitic rocks that have been emplaced in regions of current or past plate convergence ● The World's largest open-pit mine is at Bingham Canyon, Utah 

Hydraulic mining

In Hydraulic mining, a high-pressure jet of water is blasted through a nozzle, called a monitor, against hillsides of ancient alluvial deposits ● Hydraulicking requires the construction of ditches, reservoirs, a penstock, and pipelines. ● The gold is recovered in sluice boxes where mercurymay be added to aid recovery at low costs ● Efficient but highly destructive to the land

Mineral deposit

Locally rich concentrations of minerals

Metallic Reserves

Metallic ○ metals are grouped based on crustal abundance ○ Abundant metals:require large amounts of energy for production ■ world's industrialized nations are the greatest consumers of these metals ■ crustal abundances are more than .1% ○ Scarce metals:concentrated in sulfate deposits ■ crustal abundances are less than .1%

Surface Mining

Much of the coal now mined in the U.S. is extracted by surface operations which involve removing rock and soil that overlie the coal beds. Compared to underground mining, surface mining is generally less expensive, safer for miners, and facilitates more complete recovery of coal. ● Surface mining causes more extensive disturbances to the land and has the potential for serious environmental consequences unless the land is carefully reclaimed ● There are 3 methods of surface mining, contour mining, area mining, and mountaintop mining. 

Nonmetallic reserves

Nonmetallic ○ industrial minerals: used in chemical industry ○ agricultural minerals constuction material

Acid mine drainage

Origin of acid mine drainage shows us interaction of 4 of the spheres of the Earth system ● Sulfide ore bodies (lithosphere component) combine with oxygen (atmosphere component) and underground and surface water (hydrosphere component). Certain bacteria (biosphere component) thrive in this acidic environment, deriving energy from the conversion of one type of iron to another. This causes red, orange, and yellow iron-rich precipitates to settle on aquatic plant life and stream bottoms ○ Heat generated by this activity speeds up the process

Ores

Reserves of metallic minerals

Wildlife restoration

SMCRA regulations for coal mining and most state reclamation regulations for hardrock mining require healthy vegetation to be reestablished once mining has ended -permanent vegetation is the principal means of minimizing erosion and reducing stream siltation -The types of vegetation that are to be used in reclamation are stipulated in the original mine permit, based on pre-mining vegetation and intended post- mining uses - commonly a straw mulch or chemical soil stabilizer is applied after seeding to inhibit erosion and retain moisture

Water

SMCRA requires that a surface coal-mining operation be conducted in a way that will maintain hydrological balance and ensure the availability of an adequate water supply for post-mining use during surface coal mining all of the runoff water that collects in teh pit is required to be collected and treated

Strip mining

Strip mining is a type of surface mining which involves the removal of a thin layer of material known as an "overburden" to access buried deposits of useful minerals. This type of mining is only effective in areas where mineral deposits are very close to the surface, making it feasible to quickly and easily remove the overburden to get to them. Classically, strip mining is used to mine tar sand and coal.

mineral reserves

Sufficiently enriched concentrations of minerals Mineral reserves= deposits of earth materials from which useful commodities are economically and legally recoverable with existing technology

Affect of sulfur in mines

Sulfer dioxide reacts with water forming sulfuric acid ● this not only acidifies surface and underground waters, but it also expedites the leaching, release, and dispersal of iron, zinc, copper, adn other toxic metals into the environment. ● such substances kill aquatic life and erode human-made structures such as concrete drains, ect.

Impacts of underground mining

The most far reaching effects of underground mining are ground subsidence, the collapse of the over-burden into mined-out areas, and acid mine drainage, the drainage of acidic water from mine sites. ● AMD is generally considered to be the most serious environmental problem facing the mining industry today, as some acid drainage may continue for hundreds of years ● AMD can result when high-sulfer coal or metallic-sulfide ore bodies are mined. ● Pyrite and other metallic-sulfide minerals are prevalent in the walls of underground mines and open pits in the tailing, finely ground, sand-sized waste material from the milling process that remains after the desired mineral has been extracted; and in other mine waste 

Open pit mining

The only practical way to extract many minerals when they occur in a very large low-grade-ore body near the surface -the process requires processing enormous amounts of material adn is devastating to the landscape - the epitome of open-pit mining is the bingham Canyon copper mine in Utah, where about 3.3 billion tons of material have been removed since 1906 - the mine itself disrupts the landscape and the increased surface ara of the broken and crushed rock from mining and milling sets the stage for erosion and teh leaching of toxic metals to the environment 

Boulder river basin, Montana

These lands have been mined since the late 19th century ● Metals extracted included gold, lead, silver, and zinc ● Environmental degradation drew together a cooperative partnership to clean up this mess ● Major contributor of contaminants to High Ore Creek has been the Comet Mine (fish couldn't survive) ● The remediation improved water quality - reclamation consisted of three basic steps: isolate, encapsulate, and keep dry ○ Turned out to be very successful and these techniques are utilized in the remediation of other AMLs in the state 

Critical minerals and strategies

When the unequal supply pattern of minerals results in the scarcity of particular mineral resources that are crucial to a nation's economy, those minerals become critical or even strategic in the event of a national emergency

volcanogenic deposits

When volcanic activity vents fluids to the surface, sometimes associated with ocean-floor hot-spring black smoker activity, volcanogenic deposits are formed

Contour mining

accomplished by cutting into the hillside to expose the coal and then following the coal seam around the perimeter of the hill. ● horizontal strips are cut, enlarging each strip around the hillside until the thickness of the overburden is so great that further exposure of the coal best would not be cost-effective. ● sites must be reclaimed and this is done by backfilling spoil, the broken grafments of waste rock removed in order to mine the coal, against the highwall and spreading and compacting as necessary to stabilize the reclaimed hillside. 

Pegmatites

are small, tabular-shaped, very coarse-grained, intrusive igneous bodies that may be important sources of mica, quartz, feldspar, beryllium, lithium, and gemstones

Concentration factor

enrichment expressed as the ratio of the element's abundance in the deposit to its average continental-crust abundance A basic tenet of mineral commodity economics is that it is unlikely that we will ever run out of a useful substance ● This is because there are always deposits of any substance that have lower concentrations than are currently economical to mine

Hydrothermal deposits

hydrothermal mineral deposit, any concentration of metallic minerals formed by the precipitation of solids from hot mineral-laden water (hydrothermal solution). The solutions are thought to arise in most cases from the action of deeply circulating water heated by magma. Other sources of heating that may be involved include energy released by radioactive decay or by faulting of the Earth's crust. The mineral deposit may be precipitated from the solution with or without demonstrable association with igneous processes. These waters may deposit their dissolved minerals in openings in the rock, thus filling the cavities, or they may replace the rocks themselves to form so-called replacement deposits. The two processes may occur simultaneously, the filling of an opening by precipitation accompanying the replacement of the walls of the opening.

Smelters

large industrial plants that process ore concentrates and extract the desired elements, produce more air pollution, in the form of flue dust, than any other single industrial activity

Dredging

much U.S. production of sand and gravel is accomplised by dredging rivers, and large dredges are used to mine placer tin deposits in southeast Asia ● Dredging causes significant disruption to the landscape ● Scarification remains from former dredging in river bottoms in many western states and elsewhere in the world. surface mining

Placer deposits

placer deposits: mineral deposits concentrated by moving water ○ Ex: river deposits formed by glacial outwash (resulting from runoff go glacier meltwater

Mountaintop removal mining

use primarily in the eastern U.S. to recover coal that underlies the tops of mountains ● after the coal is removed, the mined area is returned to its approximately original shape or left as flat terrain. ● Mountaintop-removal mining involves removal and disposal of the waste rock, which includes carcinogenic chemicals used to was the coal for market and toxic metals such as mercury and arsenic. ● Commonly, the waste is simply dumped in hollows and valleys in West VIrginia and Kentucky, more than 1,200 miles of streams and rivers have been destroyed, ecosystems devastated, and whole valleys eliminated

Reclaiming open pit coal mines

● There are 5 steps in reclaiming abandoned coal mine lands: ○ Drainage control to eliminate acid mine drainage ○ Stabilization of landforms ○ Revegetation ○ Ongoing monitoring ○ Returning the land to use 

Area mining

● commonly used to mine coal in flat and gently rolling terrain, principally in the midwestern and western states ● enormous equipment is used to remove the overburden, mine the coal, and reclaim the land. ● Topsoil is stockpiled in special areas and put back in place when the mining is completed ● After replacing it is tilled with traditional farming methods to reestablish it as crop or pasture land. often leaves the land better and more productive than before