Copper is one of the more expensive varieties of non-ferrous metal and is widely used around the world (and has been for some 11,000 years). Copper is a soft metal with very high thermal and electrical conductivity. These properties make copper ideal for use in many different applications: from electromagnets to roofing materials and from electrical wiring to sanitary piping. Due to its relatively high price, a lot of copper is recycled, with about 15% of all copper used being recycled copper. Besides the high cost of the material itself, copper mining from ore also has a considerable negative impact on the environment. Copper mining is an energy-intensive operation and the soil around copper mines becomes heavily polluted. Using recycled copper therefore saves on costs and on the environment. Copper is highly recyclable and it is estimated that some 80% of all copper ever mined is still in circulation.