In order to know the variable rock drillability and select the most suitable drilling rig to get the best drilling efficiency. Firstly, we have to be friend with rock that KNOW THEM.

This course will introduce the basic knowledge of rock classification based on origin, the difference of rock properties and their effects on drilling. The methods of testing for rock properties will be explained. It is helpful to get basic drilling knowledge

  • Drillability is primarily related to the rate that a drilling tool penetrates into the rock, in a wider sense it also includes the ability to achieve good hole quality in general. 
  • Geological and mechanical properties of rock are interrelated, both must be taken into account when planning drilling and blasting operations. 
  • Rock properties and characteristics are determined primarily by origin, formation and mineral composition
  • A rock type consists of one or several minerals, example: Granite contains: Quartz, Feldspar, Plagioclase, Biotite, Magnetite,…..
  • A mineral consists of one or several elements, example: Quartz: SiO2; Biotite: K(Mg,Fe)3AlSi3O10(F,OH)2
  • There are three rock types based on origin as following:
  • Igneous rocks
  • Sedimentary rocks
  • Metamorphic rocks





Igneous rocks


  • Igneous rocks are formed when magma solidifies, plutonic(intrusive) rocks solidify deep down and have coarse grains, volcanic (extrusive) rocks solidify on the surface and have fine grains.
  • It is about 95% of the earth’s crusty made up of igneous rock.
  • It depends on at what depth the rock solidifies it is given different names even if the composition is the same. 
  • Igneous rocks are classified according to their silicon (SiO2) content, the greater the silicon content the larger the amount of quartz in the rock

Sedimentary rocks

  • The processes that produces sedimentary rocks includes weathering, erosion and deposition in seas and lakes, there are three main types of sedimentary rocks:
    • a) Clastic, from rock particles fragments and pebbles (sandstone)
    • b) Organic, from skeletal remains and marine organism(limestone)
    • c) Chemical, from precipitation of minerals in water (gypsum)
  • It is about 75% of the earth’s surface is covered by sedimentary rock.

Metamorphic rocks

  • Metamorphic rocks are rocks that were originally sedimentary, igneous or even metamorphic rocks that by influence of pressure and/or temperature, changed form is as following:
    • a) Pressure causes the rock to change form structurally
    • b)Temperature causes the rock to change minerally






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