The midas II linear programing model of the U.S. copper industry was revised to reflect conditions resulting from the 1980-81 recession, the high cost of money, and reduced demand. Various scenarios were run to evaluate the impact of tax reductions, high rates of economic growth, severance tax, and changes in pollution control requirements on copper demand, supply, and price. The most stimulating effects resulted from high demand generated by an increased rate of economic growth. The next most stimulating effects resulted from a 20% tax cut together with no pollution control costs. The tax cut alone caused little change from the base case. The most devasting effects resulted from requiring an 18% rate of return combined with an intergovernmental council of copper-exporting countries embargo. The 18% rate of return reduced U.S. production that was made up from imports. When the imports were not available, the impact was drastic. The model seemed to perform appropriately under the circumstances prescribed.