Mineral adequacy, exploration success, and mineral policy in the United States

Abstract

Abstract Data on copper reserves, recent discovery rates, and historical tonnage-grade relations indicate that the U.S. can be approximately self-sufficient in copper to the year 2000 by mining grades similar to those presently being mined, and given reasonable exploration efforts, the U.S. can supply its demand for about 100 years by mining inferred tonnages above 0.1% Cu. However, recent price trends and the increased cost of mining lower grade ore will increase the price of copper at a rate faster than the general inflation rate, and may lead to significant imports because of their cheaper price. Compilation of the discovery history for copper shows that the Hubbert Gaussian curve is not applicable to predict copper reserves, and may not be applicable for other commodities. A compilation of the value of base and precious metal deposits discovered since 1940, along with meager data on cost and manpower used in exploration, indicates very little decrease in exploration effectiveness over the 40-year interval, in contrast to oil and uranium. Collection of better data on expenditures for metallic mineral exploration is recommended.