Introduction to Mining

8/3/2019 Introduction to Mining

http://slidepdf.com/reader/full/introduction-to-mining 1/12

E-MINING

What is mining?

Mining is the extraction (removal) of minerals and metals from earth.Manganese, tantalum, cassiterite, copper, tin, nickel, bauxite(aluminum ore), iron ore, gold, silver, and diamonds are just someexamples of what is mined.

Why mine?

Mining is a money making business. Not only do mining companiesprosper, but governments also make money from revenues. Workers

also receive income and benefits .

What are the minerals and metals used for?

Minerals and metals are very valuable commodities. For example,manganese is a key component of low-cost stainless steel. It is alsoused to de-color glass (removing greenish hues), but in higher concentrations, it actually makes lavendar-colored glass. Tantalum isused in cell phones, pagers, and lap-tops. Cooper and tin are used to

make pipes, cookware, etc. And gold, silver, and diamonds are usedto make jewelry.

Large scale mining versus small scale mining:

y Large scale mining usually involves a company with manyemployees. The company mines at one or two large sites andusually stays until the mineral or metal is completely excavated.An example of a large scale mine is the Serra Pelada mine in

Brazil which yielded 29,000 tons of gold from 1980 to 1986 andemployed 50,000 workers (Kricher, 1997).

y Small scale mining usually involves a small group of nomadicmen. They travel together and look for sites which they thinkwill yield gold or another valuable metal or mineral. Small scalemining occurs in places such as Suriname, Guyana, Central

Africa, and many other places around the world. Some



researchers believe that small scale mining is more harmful tothe environment and causes more social problems than largescale mining. This will become apparent later in the lesson.

MINING·SMining may well have been the second of humankind·s earliestendeavors³ granted that agriculture was the first. The two industries rankedtogether asthe primary or basic industries of early civilization. Little has changedin theimportance of these industries since the beginning of civilization. If weconsider

fishing and lumbering as part of agriculture and oil and gas productionas partof mining,then agriculture and mining continue to supply all the basicresources used by modern civilization.

The history of mining :is fascinating. It parallels the historyof civilization,with many important cultural eras associated with andidentified by variousminerals or their derivatives.

MINING TERMINOLOGY:y Most of themining terminology is introduced in the

sections of this book where they aremost applicable. Some general terms are best defined at the

outset; these areoutlined here. For a complete list of mining terminology,seea standardreference (Gregory,1980; American Geological Institute,1997). The followingthree terms are closely related:





waste

ADVANCEMENTS IN MINING TECHNOLOGYAs one of humanity·s earliest endeavors³and certainlyone of its first

organized industries³mining has an ancient and venerablehistory (Gregory,1980).

y To understand modern mining practices,it is useful totrace the

evolution of mining technology,which (as pointed out earlier in this chapter) has paralleled human evolution and the advance of civilization.

y Mining in its simplest form began with Paleolithichumans some 450,000

years ago,evidenced by the flint implements that have been

found with thebones of early humans from the Old Stone Age (Lewis andClark,1964 ). Our ancestors extracted pieces from loose masses of flint or from easily accessedoutcrops and,using crude methods of chipping theflint,shaped them into toolsand weapons.

y By the New Stone Age,humans had progressed tounderground

mining in systematic openings 2 to 3 ft (0.6 to 0.9m) inheight and more than30 ft (9m) in depth (Stoces,1954 ).





y mining proper and are the main province of the miningengineer. Reclamation

has been added to these stages since the firstedition,to reflect the times.

Closure and reclamation of the mine site has become anecessary part of the

mine life cycle because of the demands of society for acleaner environment and

stricter laws regulating the abandonment of a mine. Theoverall process of

developing a mine with the future uses of the land in

mind is termed sustainabledevelopment.(1) This concept was defined in a book entitled Our

Common Future(World Commission on Environment and

Development,1987 ) as ¶¶developmentthat meets the needs of the present without

compromising the ability of

future generations to meet their own needs.·· The ideaspresented therein have

been widely endorsed as a practical means of providingfor future generations.

EXPLORATIONThe second stage in the life of a mine,exploration,determines as accurately aspossible the size and value of a mineral deposit,utilizingtechniques similar tobut more refined than those used in prospecting. The line of demarcation



between prospecting and exploration is not sharp; in fact,adistinction maynot be possible in some cases...Developmentdevelopment,the work of opening a mineral deposit for exploitation is performed. With it begins the actual mining of the deposit,nowcalled the ore. Access to the deposit must be gained either

y (1)by stripping theoverburden,which is the soil and/or

rock covering the deposit, toexpose thenear-surface ore for mining or y by excavating openings from the surface toaccess more

deeply buried deposits toprepare for underground mining.

ExploitationExploitation,the fourth stage of mining, is associated withthe actual recovery

of minerals from the earth in quantity. Although developmentmay continue,the emphasis in the production stage is on production.Usually only enoughdevelopment is done prior to exploitation to ensure thatproduction,oncestarted,can continue uninterrupted throughout the life of themine.

Types of Mining

Mining is a very diverse field with different aspects to it.Just like there are many ways to prepare foods, there are



many different ways that minerals are extracted from theearth.

Here are the various ways in which mining can occur: The

main two divisions of mining are:

y Surface mining y Underground mining

Surface Mining

Surface mines are mining operations that delve into rock toextract deposits of mineral resources that are close to thesurface. In most forms of surface mining, heavy equipment,such as earthmovers, first remove the overburden (the soiland rock above the deposit). Next, huge machines such asdrag line excavators extract the mineral.Once the materialhas been removed, the land is recovered for safe use on thesurface through a process called reclamation.There areseveral variations of surface mining...



y Mountaintop removalMountaintop removal (MTR) is a relatively new form of coal mining that involves the mass restructuring of earth in order to reach sediment as deep as 1,000 feetbelow the surface. Mountaintop removal requires thatthe targeted land be first clear-cut and then leveled byexplosives.

y HydraulicHydraulic mining involves high pressure water. Thewater is sprayed at an area of rock and/or gravel and

the water breaks the rock up, dislodging ore andplacer deposits. The water/oremixture is then milled.This is a very destructive way to mine and has beenoutlawed in most areas.

y Open PitOpen pit mines involve digging large open holes in theground as opposed to a small shaft in hard rock

mining. This method of mining is most often used withminerals like copper and molybdenum. Open pit minesare very large and mostly away from urban areas.Mining operations of this scale were not done often inthe 19th century.

y DredgingDredging is a method often used to bring up

underwater mineral deposits. Although dredging isusually employed to clear or enlarge waterways for boats, it can also recover significant amounts of underwater minerals relatively efficiently and cheaply.

Underground Mining



Underground mining refers to a group of techniques used for the extraction of valuable minerals or other geologicalmaterials from the earth. In contrast to the other main typeof excavation, surface mining, sub-surface mining requiresequipment and people to operate under the surface of theearth.

There are several variations of underground mining:

y Drift miningDrift mining is a method of accessing valuablegeological material, such as coal, by cutting into the

side of the earth, rather than tunneling straightdownwards. Drift mines have horizontal entries intothe coal seam from a hillside. Drift mines are distinctfrom slope mines, which have an inclined entrancefrom the surface to the coal seam. If possible, though,drifts are driven at just a slight incline so that removalof material can be assisted by gravity.

y Slope miningSlope mining is a method of accessing valuablegeological material, such as coal. A sloping accessshaft travels downwards towards the coal seam. Slopemines differ from shaft and drift mines, which accessresources by tunneling straight down or horizontally,respectively.

y Shaft miningShaft mining is a type of underground mining done byuse of a mine shaft. A mine shaft is a verticalpassageway used for access to an underground mine.On the surface above the shaft stands a building



known as the head frame, which in previous yearscontained a winding engine and in modern.



Documents

Introduction to Mining