FOREWORD 



Minerals and mineral fuels are literally the cornerstones of modern 

 life. They constitute the source materials for most of the things we use, 

 and they supply the energy that powers our machines and heats and cools 

 the air where we live and work. In short, they are the physical source of 

 most of the necessities, conveniences, and comforts of life in the United 

 States today. 



Most mineral resources are nonrenewable, for the deposits from which 

 they are extracted are not being naturally reformed at any where near 

 the rate we are using them. They are extendable, however, in the sense 

 that new deposits are discovered by exploration, and deposits once too 

 poor in quality to recover economically are made available by advancing 

 technology. And, of course, many mineral products can be recycled. 



Because of our dependence on minerals and mineral fuels, the question 

 of the magnitude of usable resources is of mounting concern. Generally 

 the problem has been assessed in terms of proved reserves — workable de- 

 posits that have already been discovered and inventoried. To plan our 

 future, however, we need some idea of the magnitude of resources that 

 are geologically available if we are able to find and use them economically. 



As a part of our response to the Mining and Mineral Policy Act of 

 1970, the Geological Survey provides in this volume the lirst overall assess- 

 ment of mineral resources since that of the President's Materials Policy 

 Commission in 1952. It goes beyond traditional resource appraisals, which 

 have considered mainly inventoried reserves, to examine the geologic 

 availability of resources that will be needed in future generations. For 

 many minerals, these appraisals are preliminary at best, for not enough 

 is known about their origin, distribution, or the geologic environments 

 favorable for their occurrence to assess their potential now. But at the 

 least they represent a beginning, a take-oif from which we can expect to 

 enlarge our knowledge of our mineral-resource endowment with advanc- 

 ing science and exploration. 



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Rogers C. B. Morton 

 Secretary of the Interior 



