Sources

2026 Syllabus Objectives

By the end of this topic, you should be able to:

  1. Describe, with the help of a simple diagram for each method, how non-renewable fuels (coal, crude oil and natural gas) are extracted: coal as obtained by open cast, adit and shaft mining methods; natural gas and crude oil obtained by exploration and drilling
  2. Understand the difference between renewable and non-renewable sources of electricity
  3. Explain (briefly) how electricity can be generated from renewable resources (hydel, wind, solar, and other possibilities such as wave, tidal, biofuels, geothermal)
  4. Understand the importance of power sources for development

1. Extraction of Non-Renewable Fuels

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Coal Extraction Methods

Coal is found in layers underground. Depending on how deep the coal is and where it's located, different methods are used to extract it.

Open-Cast Mining

This method is used when coal is found near the surface (close to the ground).

How it works:

  • The topsoil and subsoil are removed first
  • A large hole is dug into the ground
  • Giant trucks (which can carry up to 500 tonnes) drive down pathways into the hole
  • The coal is loaded onto these trucks and taken to the surface
  • This creates a massive open pit

Simple Diagram Description: A cross-section showing the land surface with layers removed, creating a large open pit. The coal seam is visible near the surface, with pathways for trucks spiraling down into the excavation.

Adit Mining

This method is used when coal is found on a hillside or mountain slope.

How it works:

  • A horizontal tunnel (called an adit) is dug straight into the hill where the coal layer is exposed
  • Workers use explosives to break the coal
  • Pillars of rock are left standing to support the roof and prevent collapse
  • Steel nets are used for extra safety
  • The coal is carried out through the tunnel

Simple Diagram Description: A cross-section of a hill showing a horizontal tunnel entrance on the slope, leading into the coal seam inside the mountain. The mineral layer runs through the hill.

Shaft Mining

This method is used when coal is deep underground (far below the surface).

How it works:

  • A vertical shaft (like a deep well) is dug straight down from the surface
  • At the bottom, horizontal tunnels are dug to reach the coal seams
  • A cage (like an elevator) carries workers and equipment up and down the shaft
  • Ventilation shafts bring fresh air down to prevent dangerous methane gas from building up
  • The coal is broken using machines or explosives and brought up through the shaft

Simple Diagram Description: A cross-section showing a vertical shaft descending from the surface through layers of rock. At the coal seam level, horizontal tunnels branch out. The diagram shows the derrick/winding gear at the surface, the cage, and the tunnels where coal is extracted.

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