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.
Copper is mined mostly in open pit mines, such as those found in Utah, New Mexico, and Chile. Chile produces the largest percentage of the world's copper with nearly 33% of the world's export. Copper is also found in the U.S., Indonesia, and Peru. Although copper has been used for thousands of years about 95% of all extracted copper was mined within the last hundred. In addition to the many mines found all over the world much of the copper we use has been recycled.