text: Based on discovery rates and existing geologic surveys, researchers estimated in 2006 that 1.6 billion metric tons of copper could be brought into use. This figure relied on the broadest possible definition of available copper as well as a lack of energy constraints and environmental concerns.
  The US Geological Survey estimated that, as of 2013, there remained 3.5 billion metric tons of undiscovered copper resources worldwide in porphyry and sediment-hosted type deposits, two types which currently provide 80% of mined copper production.  This was in addition to 2.1 billion metric tons of identified resources. Combined identified and estimated undiscovered copper resources were 5.6 billion metric tons, 306 times the 2013 global production of newly mined copper of 18.3 million metric tons.