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Mining

2007 Schools Wikipedia Selection. Related subjects: Business

   Mining is the extraction of valuable minerals or other geological
   materials from the earth, usually (but not always) from an ore body,
   vein, or (coal) seam. Materials recovered by mining include bauxite,
   coal, copper, gold, silver, diamonds, iron, precious metals, lead,
   limestone, nickel, phosphate, oil shale, rock salt, tin, uranium, and
   molybdenum. Any material that cannot be grown from agricultural
   processes must be mined. Mining in a wider sense can also include
   extraction of petroleum, natural gas, and even water.
   Chuquicamata, the largest open pit copper mine in the world, Chile
   Enlarge
   Chuquicamata, the largest open pit copper mine in the world, Chile

History

   Miners at the Tamarack Mine in Copper Country, Michigan, USA in 1905
   Enlarge
   Miners at the Tamarack Mine in Copper Country, Michigan, USA in 1905

   The oldest known mine in the archaeological record is the " Lion Cave"
   in Swaziland. At this site, which by radiocarbon dating is 43,000 years
   old, paleolithic humans mined for the iron-containing mineral hematite,
   which they ground to produce the red pigment ochre. Sites of a similar
   age where Neanderthals may have mined flint for weapons and tools have
   been found in Hungary.

   Ancient Egyptians operated malachite mines at Wady Maghareh on the
   Sinai Peninsula and at Timna in the Negev. At first, the bright green
   stones were used for ornamentation and for pottery glaze, but
   approximately 1,200 BCE, Egyptians discovered that malachite could be
   converted into copper by the application of intense heat and air.

   In North America there are ancient, prehistoric copper mines along Lake
   Superior that were part of an extensive native trade network of copper
   tools, points, arrowheads, and artifacts. Some copper points that were
   found are over 3000 to 4000 years old, and copper was traded
   throughtout the continent along major river routes. In addition,
   quartz, flint, and other minerals were are also mined, worked, and
   traded. In Manitoba there are ancient quartz mines in the north, and in
   Southeastern Manitoba by the Winnipeg River in Whiteshell Provincial
   Park.

   Turquoise was mined in pre-Columbian America in the Cerillos Mining
   District in New Mexico, where a mass of rock 200 feet (60 m) in depth
   and 300 feet (90 m) in width was removed with stone tools; the mine
   dump covers 20 acres (81,000 m²). Black gun powder in mining was first
   used in a mineshaft under Banská Štiavnica, Slovakia in 1627, in the
   same town in 1762 the first Mining Academy in the world was
   established.

   Mining in the United States became prevalent in the 19th century.
   Mining for minerals and precious metals, such as in the California Gold
   Rush in the mid 1800s, was very important in westward expansion to the
   Pacific coast along with ranching and exploration of oil and gas
   fields. During this time period many white Americans and post-slavery
   African Americans, with the aid of railroads, travelled west for work
   opportunities in mining. Many western cities such as Denver and
   Sacramento originated as mining towns.

Steps in the mining process

    1. Prospecting to locate ore
    2. Exploration to find and then define the extent and value of ore
       where it is located ("ore body")
    3. Conduct resource estimate to mathematically estimate the extent and
       grade of the deposit
    4. Conduct mine planning to evaluate the economically recoverable
       portion of the deposit (and including reclamation planning)
    5. Conduct a feasibility study to evaluate the total project and make
       a decision as whether to develop or walk away from a proposed mine
       project. This includes a cradle to grave analysis of the possible
       mine, from the initial excavation all the way through to
       reclamation.
    6. Development to create access to an ore body
    7. Exploitation to extract ore on a large scale
    8. Reclamation to make land where a mine had been suitable for future
       use

Mining techniques

   Mining techniques can be divided into two basic excavation types:

          1. Surface mining

               o Open-pit mining
               o Quarrying
               o Strip mining
               o Placer mining
               o Mountaintop removal

                                    2. Sub-surface mining

                                         o Drift mining
                                         o Slope mining
                                         o Shaft mining
                                         o Hard rock mining
                                         o Borehole mining

   Solution mining is a particular mining technique that is used to mine
   minerals ( potash, potassium chloride, sodium chloride, sodium
   sulphate) which dissolve in water.

Extractive metallurgy

   The science of extractive metallurgy is a specialized area in the
   science of metallurgy that studies the extraction of valuable metals
   and minerals from their ores, especially through chemical or mechanical
   means. Mineral processing (or mineral dressing) is a specialized area
   in the science of metallurgy that studies the mechanical means of
   crushing, grinding, and washing that enable the separation (extractive
   metallurgy) of valuable metals or minerals from their gangue (waste
   material).

Environmental effects and mitigation

   Iron hydroxide precipitate stains a stream receiving acid drainage from
   surface coal mining.
   Enlarge
   Iron hydroxide precipitate stains a stream receiving acid drainage from
   surface coal mining.

   Environmental issues can include erosion, formation of sinkholes, loss
   of biodiversity, and contamination of groundwaters by chemicals from
   the mining process and products.

   Modern mining companies in many countries are required to follow strict
   environmental and rehabilitation codes, ensuring the area mined is
   returned to close to its original state, or an even better
   environmental state than before mining took place. In some countries
   with pristine environments, such as large parts of Australia, this is
   impossible despite the best intentions. Past mining methods have had,
   and methods used in countries with lax environmental regulations can
   continue to have, devastating environmental and public health effects.

   Mining can have adverse effect on surrounding surface and ground water
   if protection measures are not exercised. The result can be unnaturally
   high concentrations of some chemical elements over a significantly
   large area of surface or subsurface. Coal mining releases approximately
   twenty toxic release chemicals, of which 85% is said to be managed on
   site. Combined with the effects of water and the new 'channels' created
   for water to travel through, collect in, and contact with these
   chemicals, a situation is created where mass-scale contamination can
   occur. In well-regulated mines hydrologists and geologists take careful
   measures to mitigate any type of water contamination that could be
   caused by mines. In modern American mining, operations must, under
   federal and state law, meet standards for protecting surface and ground
   waters from contamination, including acid mine drainage (AMD). To
   mitigate these problems water is continuously monitored at coal mines.
   The five principal technologies used to control water flow at mine
   sites are: diversion systems, containment ponds, groundwater pumping
   systems, subsurface drainage systems, and subsurface barriers. In the
   case of AMD, contaminated water is generally pumped to a treatment
   facility that neutralizes the contaminants.

   Some examples of environmental problems associated with mining
   operations are:

          Ashio Copper Mine, Ashio, Japan was the site of substantial
          pollution at end of the nineteenth century

          Berkeley Lake, an abandoned pit mine in Butte, Montana that has
          filled with water which is now acidic and poisonous. In 2003, a
          water treatment plant came on-line, initially treating "new"
          water entering the pit and thereby reducing the rate of rise of
          pit water. Treated water is currently used in the concentrator
          of the nearby Montana Resources Continental Pit, but it is clean
          enough to return to Silver Bow Creek. Eventually, water in the
          pit itself will be treated.

          Britannia Mines, a former copper mine near Vancouver, British
          Columbia. Copper from the abandoned mine washes into Howe Sound,
          polluting the water. No animal life remains there now. - Latest
          reports are that after a water treatment plant was put in, fish
          are returning to Britannia Bay - maybe for the first time ever.
          The name used by the First Nations tribes of Britannia Beach,
          even before mining started, means "The Place of No Fish".

          Scouriotissa, a copper mine in Cyprus that has been abandoned.
          Contaminated dust blows off this site.

          Tar Creek, an abandoned mining area in Picher, Oklahoma that is
          now an Environmental Protection Agency superfund site. Water in
          the mine has leaked through into local groundwater,
          contaminating it with metals such as lead and cadmium.

   Although such issues have been associated with some mining operations
   in the past, modern mining practices have improved significantly and
   are subject to close environmental scrutiny. To ensure completion of
   reclamation (restoring mine land) the Office of Surface Mining requires
   that mining companies post a bond to be held in escrow until
   productivity of reclaimed land has been convincingly demonstrated.
   Since 1978 the mining industry has reclaimed more than 2 million acres
   (8,000 km²) of land. This reclaimed land has renewed vegetation and
   wildlife in previous mining lands and can even be used for farming and
   ranching.

   For further reading on reclamation of former mining sites, see
   Restoration ecology.

Mining industry

   While exploration and mining can sometimes be conducted by individual
   entrepreneurs or small business, most modern-day mines are large
   enterprises requiring large amounts of capital to establish.
   Consequently, the mining sector of the industry is dominated by large,
   often multinational, mostly publicly-listed companies. See
   Category:Mining companies for a list. However, what is referred to as
   the 'mining industry' is actually two sectors, one specializing in
   exploration for new resources, the other specializing in mining those
   resources. The exploration sector is typically made up of individuals
   and small mineral resource companies dependant on public investment.
   The mining sector is typically large and multi-national companies
   sustained by mineral production from their mining operations.

Employment in the U.S. mining industry and government regulations

   Miners today do more than just dig tunnels in the Earth's subsurface.
   There are many different jobs, direct and indirect, in the mining
   industry, ranging from engineers and lab technicians to geologists and
   environmental specialists. Beyond employment directly linked to
   mine-site activity, the modern mining industry also employs many other
   professionals, including accountants, lawyers, sales representatives,
   public relations specialists, not to mention thousands of men and women
   involved who manufacture the machines and equipment necessary to mine
   minerals.

   Employment in the mining industry offers highly competitive wages and
   benefits, especially in rural or remote areas. According to the Bureau
   of Labor Statistics (BLS), wages for coal miners are 30% higher than
   the wage earned by the average American. Employees possessing at least
   a bachelor's degree in mining or geological engineering can earn a
   median pay of over $80,000 annually.

   The US Bureau of Labor Statistics estimates that 675,000 are employed
   in the natural resources and mining sector. Estimated employment by
   selected specific commodity (including mine, mill, smelter, and quarry
   workers) listed below is from US Geological Survey Mineral Commodity
   Surveys:
     * Crushed Stone - 79,700 workers
     * Copper - 7,000
     * Cement - 18,000
     * Sand and Gravel - 38,300
     * Gold - 7,600
     * Aluminium - 56,000
     * Iron Ore - 4,400
     * Platinum Group Metals - 1,600
     * Salt - 4,100
     * Phosphate Rock - 2,900

   The mining industry has an experienced but aging workforce with a mean
   average age of 50 years and median of 46 years. Indeed, while the
   industry will require new employees to meet future demand, the largest
   dilemma currently facing mine operators is finding employees to fill
   vacancies left by a generation of miners, mine engineers, senior
   managers, technical experts and others who are set to retire between
   2005 and 2015. However, the industry is struggling to meet that demand
   due to current low enrollment levels in mining education programs at
   American colleges and universities.

   Mining is regulated under a comprehensive federal safety law (Federal
   Mine Safety and Health Act) that is administered by the Department of
   Labor's Mine Safety and Health Administration (MSHA). Currently under
   federal law, and enforced by MSHA each U.S. miner must have an approved
   worker training program in health and safety issues, including at least
   40 hours of basic safety training for new underground miners with no
   experience; 24 hours for new miners at surface mines with no
   experience; plus eight hours of annual refresher training for all
   miners.

Mine planning software

   One of the most dramatic changes in the mining industry has been the
   role that sophisticated three-dimensional mine planning software
   packages have had. Once the decision has been taken to proceed with a
   mine, one will need to create detailed designs that take into account
   the topography and infrastructure and of course, the physical
   parameters of the orebody. Manual design and old fashioned planning
   methods can be tedious and there are many road blocks that were unique
   depending on the nature of the mine (e.g., panel layouts, stope
   designs, decline design, ramp design). Initially with the 3-D
   technology relatively simple tasks - like rendering graphic images of
   drill holes - meant that it became easier for surveyors, geologists,
   mine planners, mining engineers and other technical staff to manipulate
   and visualize data. In recent years the range of integrated mine
   planning tools have meant that massively complex models can be built to
   optimize the extraction and processing of mineral resources.

   Mining Software Links
     * Datamine Datamine
     * Gemcom Gemcom
     * Mincom MinCom
     * Mintec MineSight
     * Surpac Surpac
     * Maptek Vulcan3D
     * Whittle Whittle
     * Micromine Micromine

Safety issues and improvements

   Safety has long been a controversial issue in the mining business
   especially with sub-surface mining. While mining today is substantially
   safer than it was in the previous decades, mining accidents and
   tragedies are often very high profile such as the Quecreek Mine Rescue
   saving 9 trapped Pennsylvania coal miners in 2002.

   Mining ventilation is also seen to be a safety concern for many miners
   and their family. Poor ventilation of mining causes exposure to harmful
   gases, heat and dust inside sub-surface mines. These can cause harmful
   physiological effects or death. Methane gas is a common source of
   ignition of explosions in coal mines and can propagate into the more
   violent coal dust explosions. High temperatures and humidity may result
   in any of the heat illnesses including heat stroke which can be fatal.
   Dusts can cause lung problems. These include silicosis, asbestosis and
   pneumoconiosis also known as miners lung or black lung disease.

   A ventilation system is set up to course air through the working areas
   of the mine. The air movement necessary for effective mine ventilation
   is generated by one or more large mine fans usually located above
   ground. In the United States, main fans at coal mines are required to
   be above ground. Air flows in one direction only, making circuits
   through the mine such that each main work area receives a supply of
   fresh air.

   Mining is regulated under the federal Mine Safety and Health Act by
   MSHA, which employs nearly one safety inspector for every four coal
   mines. Underground coal mines are thoroughly inspected at least four
   times annually by MSHA inspectors. In addition, miners can report
   violations, request additional inspections and cannot lose their jobs
   for doing so.

   Immediately reportable accidents and injuries are:
    1. A death of an individual at a mine;
    2. An injury to an individual at a mine which has a reasonable
       potential to cause death;
    3. An entrapment of an individual for more than thirty minutes;
    4. An unplanned inundation of a mine by a liquid or gas;
    5. An unplanned ignition or explosion of gas or dust;
    6. An unplanned mine fire not extinguished within 30 minutes of
       discovery;
    7. An unplanned ignition or explosion of a blasting agent or an
       explosive;
    8. An unplanned roof fall at or above the anchorage zone in active
       workings where roof bolts are in use; or, an unplanned roof or rib
       fall in active workings that impairs ventilation or impedes
       passage;
    9. A coal or rock outburst that causes withdrawal of miners or which
       disrupts regular mining activity for more than one hour;
   10. An unstable condition at an impoundment, refuse pile, or culm bank
       which requires emergency action in order to prevent failure, or
       which causes individuals to evacuate an area; or, failure of an
       impoundment, refuse pile, or culm bank;
   11. Damage to hoisting equipment in a shaft or slope which endangers an
       individual or which interferes with use of the equipment for more
       than thirty minutes; and
   12. An event at a mine which causes death or bodily injury to an
       individual not at the mine at the time the event occurs.

   Statistical analyses performed by the U.S. Department of Labor's Mine
   Safety and Health Administration (MSHA) show that between 1990 and
   2004, the industry cut the rate of injuries (a measure comparing the
   rate of incidents to overall number of employees or hours worked) by
   more than half and fatalities by two-thirds following three prior
   decades of steady improvement.

Machinery

   Mining machinery resembles that of other heavy industries. Heavy
   machinery is needed in mining to break and remove rocks of diverse
   hardness and toughness. Bulldozers, drills, explosives and trucks are
   important for digging into the land, especially in surface mining.
   Underground mining, like continuous mining, tends to be more
   technologically sophisticated because of the dangers and expense of
   subsurface tunneling. Continuous mining equipment manufacturers include
   Joy Mining Machinery, Caterpillar, Komatsu, Volvo, Hitachi, Dynapac,
   Terex, Dresser, TCM, Kawasaki, Furukawa, Elphinstone, Poclain and
   Demag, Eimco Elecon India Limited.

Abandoned Mines

   Stay out of old mines! Danger sign at an old Arizona mine.
   Enlarge
   Stay out of old mines! Danger sign at an old Arizona mine.

   It is estimated that there are between 700,000 and 800,000 abandoned
   mines in the United States. Many of these abandoned mines are
   associated with abandoned neighboring towns often referred to as ghost
   towns.

   Experts strongly warn against entering or exploring old or abandoned
   mines. It is estimated that approximately 25% of the abandoned mine
   lands (AML) sites pose physical safety hazards. Old mines are often
   dangerous and can contain deadly gases, snakes, and other dangerous
   animals. The entrance to an old mine in particular can be very
   dangerous, as weather may have eroded the earth/rock surrounding the
   entrance. Old mine workings, caves, etc are commonly hazardous simply
   due to the lack of oxygen in the air and this is a deadly killer which
   provides no warning to those entering such an environment.

   Every year, dozens of people are injured or killed in recreational
   accidents on mine property. It is only fair to note, however, that the
   majority of these deaths are not related to mine exploration. Drownings
   in open quarries and ATV accidents on abandoned mine properties are the
   main culprits behind these deaths. MSHA (Mine Safety and Health
   Administration) launched the "Stay Out – Stay Alive" campaign in 1999.
   "Stay Out–Stay Alive" is a national public awareness campaign aimed at
   warning and educating children and adults about the dangers of
   exploring and playing on active and abandoned mine sites.

   The Abandoned Mine Land Initiative, launched by the Western Governors
   Association and the National Mining Association is an effort focusing
   on reporting the number of high-priority AML sites, and to identify,
   measure and report on the progress of current reclamation cleanup
   programs on an annual basis.

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