According to a recently published study, "Metal Stocks and Sustainability," all of the copper in ore, plus all of the copper currently in use, would be required to bring the world to the level of the developed nations for power transmission, construction and other services and products that depend on copper. For the entire globe, the researchers, R. B. Gordon*, M. Bertram,, and T. E. Graedel, estimate that 26 percent of extractable copper in the Earth's crust is already landfilled or otherwise lost in non-recycled wastes. Current prices don't reflect those losses because supplies are still large enough to meet demand, and because new technologies have helped mines produce more efficiently. Sort of reminds us of oil price projections...say about two years ago. Here is a link to the study abstract, as published in Proceedings of the National Academy of Sciences of the United States of America. Of course your economists and your spin-pundits have already announced the study findings irrelevant, based on the usual Iron Age "horn-of-plenty" analogy: 'as stocks deplete, the free market will bouy prices, encouraging mining companies to invest more in exploration and discover new and better extraction technology, etc.' College economics classes all seem to have that magical thinking curriculum unit where students learn this, and also to overlook that every Kilo of copper lost to a landfill embodies a very large amount of fuel and electricity, and that energy prices are increasing rapidly. Also conveniently overlooked, that ore extraction and smelting takes a serious toll on the environment, and that the "easy pickings" are already either long gone or in places where mining companies and their nations of origin get no respect.
The sustainability metaphor for this is the legendary Swedish "Copper Mountain" which in the 17th Century met two thirds of the Europe's copper demand (depicted in graphic) and was closed, after being fully depleted, in the early 1990's.
Of course we will have plenty of copper for centuries to come, assuming that developing nations like China and India don't follow the western pattern.
UPDATE: in response to the interesting comments on prospects for landfill mining in the future (below) I would like to point out that formally managed, catch-all landfills are not the norm in much of the world. In Europe municipal incineration is the norm for combustibles: recyclables are handled separately, in large part. In Japan, open burning and proper incineration of of construction debris and some trash are common. In the developing world, where population density is high and much land is in cultivation it's wide open. Formal large landfills just won't exist in many areas as a result.