Differentiate fixed costs and variable costs. 1  Total cost is the sum of fixed and variable costs.  Variable costs change according to the quantity of a good or service being produced. The amount of materials and labor that is needed for to make a good increases in direct proportion to the number of goods produced.
Xtrata is a top five producer of copper, thermal coal, coking coal, ferrochrome, zinc and nickel and has operations in 19 countries. The company's copper production in 2010 was over 900 thousand metric tons and it has copper facilities located in Australia, Chile, Peru, Argentina, and Canada.
Welsh Copper Society. The Welsh copper industries of mining, smelting and refining created generations of talented workers. Although dominated by men, women took part too, particularly in the North Wales mines.