MINERAL RESOURCE ESTIMATES AND PUBLIC POLICY 



13 



EXAMPLES OF ESTIMATES OF POTENTIAL 

 RESOURCES 



For most minerals, the chief value of this classi- 

 fication at present is to call attention to the informa- 

 tion needed for a comprehensive appraisal of their 

 potential, for we haven't developed the knov\^ledge 

 and the methods necessary to make meaningful 

 estimates of the magnitude of undiscovered deposits, 

 and we don't know enough about the cost of pro- 

 ducing most presently noncommercial deposits to 

 separate paramarginal from submarginal resources. 

 Enough information is available for the mineral 

 fuels, however, to see their potential in such a 

 framework. 



The fuel for which the most complete information 

 is available is the newest one — uranium. As a result 

 of extensive research sponsored by the Atomic En- 

 ergy Commission, uranium reserves and resources 

 are reported in several cost-of-recovery categories, 

 from less than $8 to more than $100 per pound of 

 UaOg. For the lower cost ores, the AEC makes peri- 

 odic estimates in two degree-of-certainty categories, 

 one that it calls reasonably assured reserves and the 

 other it calls additional resources, defined as ura- 

 nium surmised to occur in unexplored extensions of 

 known deposits or in undiscovered deposits in known 

 uranium districts. Both the AEC and the Geological 

 Survey have made estimates from time to time of 

 resources in other degree-of-certainty and cost-of- 

 recovery categories. 



Ore in the less-than-$8-per-pound class is minable 

 now, and the AEC estimates reasonably assured 

 reserves to be 143,000 tons and additional resources 

 to be 167,000 tons of UsOs — just about enough to 

 supply the lifetime needs of reactors in use or 

 ordered in 1968 and only half that required for 

 reactors expected to be in use by 1980. The Geo- 

 logical Survey, however, estimates that undiscov- 

 ered resources of presently minable quality may 

 amount to 750,000 tons, or about 2.5 times that in 

 identified deposits and districts. Resources in the 

 $8- to $30-a-pound category in identified and undis- 

 covered deposits add only about 600,000 tons of 

 UsOg and thus do not significantly increase potential 

 reserves. 



But tens of millions of tons come into prospect 

 in the price range of $30 to $100 per pound. Ura- 

 nium at such prices would be usable in the breeder 

 reactor. The breeder, of course, would utilize not 

 only U"^ but also U"^ which is 140 times more 

 abundant than U'='. Plainly the significance of ura- 

 nium as a commercial fuel lies in its use in the 

 breeder reactor, and one may question, as a number 



of critics have (for example, Inglis, 1971), the 

 advisability of enlarging nuclear generating capacity 

 until the breeder is ready for commercial use. 



Until recently the only information available about 

 petroleum resources consisted of estimates of proved 

 reserves prepared annually by the American Petro- 

 leum Institute and the American Gas Association, 

 plus a few estimates of what has been called ulti- 

 mate production, that is, the total likely to be 

 eventually recovered. A few years ago, however, the 

 API began to report estimates of total oil in place 

 in proved acreage, and the Potential Gas Committee 

 began to estimate possible and probable reserves of 

 natural gas, defining them as consisting of gas 

 expected to be found in extensions of identified fields 

 and in new discoveries in presently productive strata 

 in producing provinces. It also introduced another 

 category, speculative resources — equivalent to what 

 I have called "undiscovered" — to represent gas to 

 be found in nonproducing provinces and in presently 

 unproductive strata in producing provinces. 



In 1970 the National Petroleum Council released 

 a summary of a report on "Future Petroleum Prov- 

 inces of the United States," prepared at the request 

 of the Department of the Interior, in which it re- 

 ported estimates of crude oil in the combined 

 probable-possible class and in the speculative cate- 

 gory. In addition, NPC estimated the amounts that 

 would be available under two assumptions as to the 

 percent of the oil originally in place that might be 

 recovered in the future (table 2) . NPC did not assess 

 the cost of such recovery, but the average recovery 

 is now about 30 percent of the oil in place, and NPC 

 expects it to increase gradually to about 42 percent 

 in the year 2000 and to 60 percent eventually. The 

 NPC estimates do not cover all potentially favorable 

 areas either on land or oif shore but, even so, in the 

 sum of these various categories NPC sees about 12 

 times as much oil remaining to be discovered and 

 produced as exists in proved reserves alone. 



The Potential Gas Committee's estimates of po- 

 tential gas resources similarly do not cover all 

 favorable areas, but they indicate that resources in 

 the probable, possible, and speculative categories 

 are about twice that of proved reserves and past 

 production. Because about 80 percent of the gas 

 originally in place is now recovered, paramarginal 

 and submarginal resources in ordinary gas reservoirs 

 are not as large as for crude oil. Paramarginal and 

 submarginal gas resources may be significant, how- 

 ever, in kinds of rocks from which gas is not now 

 recovered, namely impermeable strata and coal. In 

 the Rocky Mountain province, for instance, Haun, 

 Barlow, and Hallinger (1970) recently estimated 



