March 24, 2007 2:44am CST
The distribution of valubale minerals is highly unven and ming may become profitable only for a few years. When the mineral ores get exhausted or when mining becomes uneconomical, miners leave the site. miners usually live in termporary shelters near the site of mining. Quality of the roe, geological conditions of occurrence, depth of mining and accessibility are important factors in selecting the site for commerical exploitation. The opening up of mines leads to the provision of transport facilities and opening up of the area for settlement. The gold rush led to the migration of people to California and Western Asutralia. Though power operated tools are used for mining, miners face a difficult task, especailly when they work at great depths. Fires, floods and caving in of ceiling lead to accidents in mines. Apart from the mining of ores, large number of persons are employed in processing and refining the ores. Such processing units are located near the mines or near the consuming centres. As it is more economical to transport crude petroleum than a variety of petroleum products, oil refineries are located near ports and consuming centres.