The role of exploration in iron and copper supply

The development histories of approximately 200 each iron and copper mine openings in the non-centrally-planned-economies from the mid-1800s through the mid-1980s are analyzed to determine the role of exploration in mineral supply. The research shows that approximately 75 percent of the iron mines and 50 percent of the copper mines opened since World War II do not result from the prompt development of new discoveries. The mine openings result from the reevaluation of mineralization or orebodies that are previously recognized, which become economic under changed technologic or market conditions. Although the incentive for exploration is normally the expectation that high-profit deposits exist to be found, the supply of new mines does not depend critically on whether such high-profit deposits are discovered. Studies that predict scarcity of resources arising from the failure of exploration to uncover new, highprofit deposits thus do not adequately explain the mineral supply process.