Open cast mining. Image credit

ZIMSEC O Level Geography Notes:Resource Exploitation:Mining: Types of Mining


  • The open cast method is used when mineral deposits occur in horizontal seams which are near the surface not more than 50 meters deep.
  • This method involves blasting which is carried out of scatter rocks.
  • The overburden is then removed using large mechanical excavators or draglines.
  • Open cast mining is used to extract coal at Hwange, asbestos in Mashava, nickel at Trojan mine in Bindura.

Advantages of opencast

  • It is a fairly cheap and simple method of extracting shallow seams
  • It is safer compared to the alternatives as there is no risk of tunnel collapse, explosions or gas poisoning
  • The open pit allows easy access for humans and machines
  • Requires less machinery and investment
  • There is high selectivity which allows the operators to quickly get rid of low grade ores


  • Blasting causes structural damage to buildings as well as noise pollution.
  • Use of explosive is a potential danger to miners.
  • Opencast leaves the land scarred.
  • Deforestation causes severe soil erosion. Mine dumps destroy the natural beauty of the land and landslides can occur on unstable dumps.


A miner descending into a shaft. Image

  • Shaft method is used to extract deep seated ores over 50 metres deep.
  • The method involves the sinking of vertical or inclined shafts down to the level of the seams.
  • Horizontal tunnels are built following the seams.
  • Shaft mining is used to extract coal at Hwange, chrome in Shurugwi and gold in Mazowe.


  • The method allows extraction of deep seams.
  • There is less deforestation.


  • It is very expensive.
  • Cave-ins and toxic gases are a great risk.
  • Deep mines can cause earth tremors.
  • Flooding can be a danger to miners.


Adit/Drift abandoned silver mine. Image credit

  • This method is used to extract minerals that appear on the sides of mountains and valleys.
  • This form of mining involves building horizontal or inclined tunnels along the mineral seam.
  • Other structure such as conveyor belts and railway lines are built to facilitate the extraction of the minerals.


  • It is fairly cheap method and its safer than shaft mining method
  • Can be drained using a force of gravity
  • Minerals can be transported more easily and cheapily


  • Tunnels can cave-in.
  • Landslides can occur.
  • Can only be constructed where topology permits

To access more topics go to the O Level Geography Notes page