Policy makers, mineral exploration experts, and regional planners decide how public lands, which may contain undiscovered resources, should be used or whether to invest in exploration for minerals on a regular basis. Decisions are also made concerning mineral resource adequacy, national policy, and regional development. This book makes explicit the factors that can affect a mineral-related decision so that decision-makers can clearly see the possible consequences of their decisions. Based on work done at the US Geological Survey, the authors address the question of the kinds of issues decision-makers are trying to resolve and what forms of information would aid in resolving these issues. The goal of the process discussed is to offer unbiased quantitative assessments in a format needed in decision-support systems so that consequences of alternative courses of action can be examined with respect to land use or mineral-resource development. An integrated approach focuses on three assessment parts and the models that support them. Although the concepts presented are straightforward and understandable, in assessments, carefully listening to the experts in other disciplines leads to better products. Navigating through and making sense of QRA requires not just learning rules and equations, but life experiences and common sense. The judgment required to understand which tools to apply are best learned by example and experience. This will be useful to governmental or industrial policy makers, managers of explorations, planners of regional development, and similar decision-makers. 1. Introduction 2. Mineral Resources and Society 3. Descriptive Models 4. Deposit-Density Models 5. Economic Analysis 6. Grade-and-Tonnage Models 7. Delineation of Permissive Tracts 8. Estimating the Number of Undiscovered Deposits 9. Integration of Grades, Tonnages, Number of Deposits, and Economic Effects 10. Exploration Risk 11. The Future of Quantitative Resource Assessments Appendix 1. Conversion of Units Appendix 2. Algorithm for Estimating Probabilities for a Set of Number-of-Deposit Estimates Glossary References Index Donald Singer has been a world leader in methods of quantitatively assessing undiscovered mineral resources with publications on resource assessments, deposit models, quantitative methods, and exploration strategies. The SEG awarded him its Silver Medal and the U.S. Department of Interior awarded him its Distinguished Service Award. W. David Menzie is Chief, International Minerals Section, Minerals Information Team, U.S. Geological Survey. He has conducted research on a variety of topics in economic geology, including mineral deposits modeling and methods of mineral-resource assessment. His recent research interests include the role of minerals in economic development.