UNITED STATES MINERAL RESOURCES 



studied by the National Commission on Materials 

 Policy), but the principal distinction is based on 

 current economic availability: reserves are known, 

 identified deposits of mineral-bearing rock from 

 which the mineral or minerals can be extracted 

 profitably ivith existing technology and under pres- 

 eyit economic conditions ; whereas resources include 

 not only reserves but also other mineral deposits 

 that may eventually become available — either known 

 deposits that are not economically or technologically 

 recoverable at present, or unknown deposits, rich or 

 lean, that may be inferred to exist but have not yet 

 been discovered. A simple analogy from the field of 

 personal finance, suggested by our colleague J. E. 

 Gair, may be helpful in clarifying this important 

 distinction : Reserves are represented by the funds 

 in one's bank account and by other liquid assets ; 

 resources then include, in addition, all other assets 

 and, more importantly, all income one may expect 

 to receive, from whatever source, through the dura- 

 tion of one's lifetime. We will discuss various cate- 

 gories of resources and their relation to reserves 

 later in this introduction, but for the present we 

 would emphasize that because reserves are the only 

 part of the total resource that is immediately avail- 

 able, they are of paramount concern to the mineral 

 industry, and reserve estimates for most mineral 

 commodities are generally available and are under- 

 going constant revision. For most minerals, how- 

 ever, current reserves are only a small part of the 

 total resource. The remainder of the total — the po- 

 tential resources — are by far the most important 

 for the long term, and they receive major emphasis 

 in this book. Mineral resources, whether real or 

 potential, are geologic entities — concentrations of 

 one or more elements in the earth's crust. Because 

 such concentrations occur as the result of geologic 

 processes, the question of how and where to find 

 more of them can ultimately be resolved only 

 through the understanding of geologic principles and 

 the application of geologic insight; accordingly, the 

 chapters of this volume deal with predictions based 

 on geologic reasoning, and have been written by 

 geologists. 



A WARNING 



Implicit in the distinction between reserves and 

 resources is a serious danger, which we state now 

 and will reiterate throughout this volume: Poten- 

 tial resources are not reserves; they are "birds in 

 the bush," or to return to the analogy already used, 

 they are frozen assets and next year's income, and 

 cannot be used to pay this month's bills. No matter 

 how optimistic an outlook is engendered by estimates 



of vast resources, such resources cannot be mined, 

 much less used, until they have been converted into 

 the category of reserves, whether by discovery (of 

 undiscovered resources of minable quality), or by 

 improvements in technology (for recovering identi- 

 fied subeconomic resources), or by both. For nearly 

 all minerals, the estimates of potential resources 

 indicate quantities that may become available only 

 if tve vigorously pursue geologic and technologic 

 research to discover new mineral deposits in re- 

 gions and geologic environments that are known to 

 be favorable, to discover new favorable regions and 

 environments, to discover new kinds of mineral 

 deposits not previously recognized, to improve exist- 

 ing exploration techniques and develop new ones, 

 and to improve extractive technology for processing 

 low-grade ores that are not now economically re- 

 coverable. Readers of this volume must therefore 

 be cautioned that the resource estimates contained 

 herein are indeed estimates, not measurements ; and 

 they present an optimistic outlook for many com- 

 modities only in the context that they represent a 

 potential, not a reality. Using these estimates in 

 any efl'ort to optimize our domestic resource out- 

 look may only defeat the purpose if they are re- 

 moved from this context or are quoted without 

 adequate qualification. We have attempted to insure 

 against such misinterpretation by repeating defini- 

 tions of the appropriate resource terminology on 

 all tables of resource estimates in this volume. 



Even with these qualifiers, some may criticize this 

 volume for its articulation of a philosophy that they 

 may consider to be unrealistic. We can only offer 

 the response that in the fairly recent past, each of 

 the kinds of geologic and technologic research enu- 

 merated in the preceding paragraph has in fact 

 resulted in the conversion of potential resources 

 into minable reserves — -"rock in the box," in mining 

 parlance; a few examples are the discoveries of the 

 huge Kidd Creek zinc-copper-silver ore deposit in 

 Ontario and the disseminated gold deposits of Carlin 

 and Cortez in Nevada, and the development of tech- 

 nology for processing taconite iron ores. 



Indeed the events of the last 20 years are the best 

 reason for optimism. In 1952, the recoverable re- 

 serves of lead were estimated to be 7.1 million tons, 

 of which only about 1 million tons was called proved 

 reserve. These figures were quoted on page 41 of 

 volume 2 of "Resources for Freedom" (President's 

 Materials Policy Commission, 1952), better known 

 as the Paley report. Farther down on that page we 

 find the following statement, "The poor discovery 

 record of the past few decades provides little basis 

 for optimism that the equivalent of the southeast 



