S.5 Geo Mining Revised 2015(1) Caltec S.5

MINING Mining refers to the process of exploitation of minerals from the earth’s crust. The mining industry involves all activities related to the extraction, processing and trade in minerals. In the industrial sector, minerals are used as raw materials, as a source of power and contribute to the generation of capital when exported. Minerals are classified into two categories: the metallic and the non-metallic minerals. The metallic minerals are the most important and valuable because they are hard and have a wide range of uses. These include iron ore, tin, copper, aluminium, chromium, gold, silver, platinum, uranium, manganese, cobalt etc. The non-metallic minerals are relatively soft and weaker such as salt, potash, nitrates, sulphur, asbestos, certain precision stones e.g. diamonds. Minerals fuels are non-metallic minerals (derived from vegetation remains). These include coal, oil and natural gas. Methods of mining The methods used to remove mineral ores from the ground depend on the nature of mineral, the depth at which it occurs and its marketing value. The most common methods include: Open cast mining This method is used when the mineral ore is near the surface. The top soil (over burden) is removed and the mineral ore is blasted using explosives. The ore is then crushed to reduce the size. It is then loaded into trucks and taken to the processing plants. Shaft/ Adit/ underground mining This is used when the mineral ores lie deep below the surface (the over burden is too thick to be removed by mechanical shovels). Vertical shafts are dug into the ground to appropriate levels. From these, horizontal tunnels leading to the ore body are constructed. Supporters are provided from the roof to the floor of the tunnels. The ore is then blasted using explosives causing shattering. The ores are crushed and loaded on small wagons …