INTERCONNECTIONS BETWEEN THE DEPLETION OF MINERALS AND FUELS - THE CASE OF COPPER PRODUCTION IN THE UNITED-STATES

Analyses of the relationship between natural resources and economic de velopment frequently neglect the interdependency between the depletion of one resource and the depletion of other resources. Of particular i nterest is how energy resource extraction is affected by the depletion of nonfuel minerals due to the important role of energy in upgrading minerals to a useful state. Although this relationship has been descri bed in theoretical terms, there is little detailed empirical support t o quantify the relationship between the depletion of mineral and fuel resources, we develop a dynamic model that is based on physical, techn ological, and economic data. Our analysis quantifies the relationship between the depletion of copper in the United Slates and the depletion of fossil fuel and uranium energy resources stimulated by the increas e in demand for refined copper that is forecast for the next 50 years. The model calculates the increase in the energy cost of extracting en ergy due to the depletion of copper. The results of the model indicate that this feedback is significant. The energy cost of producing a ref ined ton of copper increases 23% over the 50-year simulation period du e to the diminution in ore grade and diminishing returns to technical change. The increase in the energy cost for copper increases the produ ction of fossil and uranium fuels, which diminishes their quality and increases their energy cost.