18 



UNITED STATES MINERAL RESOURCES 



gists would agree that minable undiscovered depos- 

 its remain in explored as well as unexplored areas 

 and that progress in our knowledge of regional 

 geology and in exploration will lead to the discov- 

 ery of many of them. With respect to unexplored 

 areas, the mineral potential of the continental mar- 

 gins and ocean basins deserves particular emphasis, 

 for the technology that will give us access to it is 

 clearly now in sight. For many critical minerals, 

 we already know of substantial paramarginal and 

 submarginal resources that experience tells us 

 should be brought within economic reach by tech- 

 nological advance. The process of substituting an 

 abundant for a scarce material has also been pur- 

 sued successfully, thus far not out of need but out 

 of economic opportunity, and plainly has much po- 

 tential as a means of enlarging usable resources. 



Extending our supplies by increasing the effi- 

 ciency of recovery and use of raw materials has 

 also been significant. For example, a unit weight 

 of today's steel provides 43 percent more structural 

 support than it did only 10 years ago, reducing pro- 

 portionately the amount required for a given pur- 

 pose. Similarly, we make as much electric power 

 from 1 ton of coal now as we were able to make 

 from 7 tons around the turn of the century. Our 

 rising awareness of pollution and its effects surely 

 will force us to pay even more attention to increas- 

 ing the efficiency of mineral recovery and use as a 

 means of reducing the release of contaminants to 

 the environment. For similar reasons, we are likely 

 to pursue more diligently processes of recovery, re- 

 use, and recycling of mineral materials than we 

 have in the past. 



Most important to secure our future is an abun- 

 dant and cheap supply of energy, for if that is 

 available we can obtain materials from low-quality 

 sources, perhaps even country rocks, as Harrison 

 Brown (1954, p. 174-175) has suggested. Again. I 

 am personally optimistic on this matter, with re- 

 spect to the fossil fuels and particularly to the 

 nuclear fuels. Not only does the breeder reactor 

 appear to be near enough to practical reality to 

 justify the belief that it will permit the use of 

 extremely low-grade sources of uranium and thor- 

 ium that will carry us far into the future, but dur- 

 ing the last couple of years there have been exciting 

 new developments in the prospects for commercial 

 energy from fusion. Gothermal energy has a large 

 unexploited potential, and new concepts are also 

 being developed to permit the commercial use of 

 solar energy. 



But many others do not share these views, and it 

 seems likely that soon there will be a demand for a 



confrontation with the full-speed-ahead philosophy 

 that will have to be answered by a deep review of 

 resource adequacy. I myself think that such a re- 

 view is necessary, simply because the stakes have 

 become so high. Our own population, to say nothing 

 of the world's, is already too large to exist without 

 industrialized, high energy- and mineral-consuming 

 agriculture, transportation, and manufacturing. If 

 our supply of critical materials is enough to meet 

 our needs for only a few decades, a mere tapering 

 off in the rate of increase of their use, or even a 

 modest cutback, would stretch out these supplies 

 for only a trivial period. If resource adequacy can- 

 not be assured into the far-distant future, a major 

 reorientation of our philosophy, goals, and way of 

 life will be necessary. And if we do need to revert 

 to a low resource-consuming economy, we will have 

 to begin the process as quickly as possible in order 

 to avoid chaos and catastrophe. 



Comprehensive resource estimates will be essen- 

 tial for this critical examination of resource ade- 

 quacy, and they will have to be made by techniques 

 of accepted reliability. The techniques I have de- 

 scribed for making such estimates have thus far 

 been applied to only a few minerals, and none of 

 them have been developed to the point of general 

 acceptance. Better methods need to be devised and 

 applied more widely, and I hope that others can be 

 enlisted in the effort necessary to do both. 



SELECTED BIBLIOGRAPHY 



Allais, M., 1957, Methods of appraising economic prospects 

 of mining exploration over large territories: Manage- 

 ment Sci., V. 2, p. 285-347. 



Armstrong, F. C, 1970, Geologic factors controlling uranium 

 resources in the Gas Hills District, Wyoming, in Wyom- 

 ing Geol. Assoc. Guidebook 22d Ann. Field Conf. : p. 

 31-44. 



Blondel, F., and Lasky, S. F., 1956, Mineral reserves and 

 mineral resources: Econ. Geology, v. 60, p. 686-697. 



Brown, Harrison, 1954, The challenge of Man's future: 

 Viking Press, 290 p. 



Bush, A. L., and Stager, H. K., 1956, Accuracy of ore-re- 

 serve estimates for uranium-vanadium deposits on the 

 Colorado Plateau: U.S. Geol. Survey Bull. 1030-D, p. 

 137. 



Buyalov, N. I., Erofeev, N. S., Kalinen, N. A., Kleschev, 

 A. I., Kudryashova, N. M., L'vov, M. S., Simakov, S. N., 

 and Vasil'ev, V. G., 1964, Quantitative evaluation of 

 predicted reserves of oil and gas : New York, Consultants 

 Bur.; translation. 



DeGeoflfroy, J., and Wu, S. M., 1970, A statistical study of 

 ore occurrences in the greenstone belts of the Canadian 

 Shield: Econ. Geology, v. 65, no. 4, p. 496-504. 



Elliott, M. A., and Linden, H. R., 1968, A new analysis of 

 U.S. natural gas supplies: Jour. Petroleum Technology, 

 V. 20, p. 135-141. 



