MODEL DESIGN IN THE PROSPECTOR CONSULTANT SYSTEM FOR MINERAL EXPLORATION**This work was supported in part by the Office of Resource Analysis of the U.S. Geological Survey under Contract No. 14-08-0001-15985, and in part by the Nonrenewable Resources Section of the National Science Foundation under Grant AER77-04499. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors, and do not necessarily reflect the views of either the U.S. Geological Survey or the National Science Foundation. | Litlas