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Minerals that lie near the earth surface are simply dug out by the process known as1. quarrying2. calcination3. open-cast mining4. sintering

Answer» Correct Answer - Option 1 : quarrying

Minerals that lie near the earth surface are simply dug out by the process known as quarrying

Quarrying:

  • Quarrying refers to extracting materials directly from the surface. 
  • It is the process of removing rock, sand, gravel, or minerals from the ground in order to use them to produce materials for construction or other uses.
  • A quarry is a type of open-pit mine in which dimension stone, rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground.
  • The operation of quarries is regulated in some jurisdictions to reduce their environmental impact.
  • The word quarry can also include the underground quarrying for stone, such as Bath stone.
  • The method of removal of stones from their natural bed by using different operations is called quarrying.

Methods of quarrying include:

  1. Digging – This method is used when the quarry consists of small & soft pieces of stones.
  2. Heating – This method is used when the natural rock bed is horizontal and small in thickness.
  3. Wedging –This method is used when the hard rock consists of a natural fissure. When natural fissures are absent then artificial fissures are prepared by drilling holes.
  4. Blasting – It is the process of removal of stones with the help of controlled explosives that is filled in the holes of the stones. The line of least resistance plays a very important role in the blasting process.

Hence, option 1 is the correct answer.

Open Cast Mining:

  • Open Cast Mining is the process under which minerals are mined near the earth's surface.
  • Opencast mining is the process that involves the removal of ore from seams relatively near the surface by means of an open pit.
  • These mines occupy a large area of land for excavation of the ore and disposal of the overburden.

Calcination:

  • Calcination, the heating of solids to a high temperature for the purpose of removing volatile substances, oxidizing a portion of the mass, or rendering them friable. 
  • Calcination, therefore, is sometimes considered a process of purification.

Sintering:

  • Sintering is the process of fusing particles together into one solid mass by using a combination of pressure and heat without melting the materials.
  • Common particles that are sintered together include metal, ceramic, plastic, and other various materials.


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