UNITED STATES MINERAL RESOURCES 



I 



I 



GOLD 



By Frank S. Simons and William C. Prinz 



CONTENTS 



Abstract of conclusions 263 



Introduction 263 



Uses 264 



Exploitation 265 



Geologic environment 266 



(Jeochemistry 266 



Mineralogy 267 



Types of gold deposits 267 



Gold-quartz lodes 267 



Epithermal ("bonanza") deposits 268 



Young placers 268 



Ancient (fossil) placers 269 



Marine placers 270 



Deposits of disseminated gold 270 



Byproduct gold 271 



Reserves and resources 271 



Prospecting techniques 273 



Problems for research 273 



References cited 274 



FIGURES 



29. Graph showing world gold production, 1890- 



1970 



30. Graph showing United States gold production, 



1930-70, and consumption, 1951-70 



TABLES 



Page 



265 

 265 



50. Equivalent weights and measures for gold 264 



51. Reserves and resources of gold in the world 



as estimated in several sources of data 271 



ABSTRACT OF CONCLUSIONS 



Most of the world's gold reserves, estimated at 1 billion 

 ounces, are in South Africa, and that country will continue 

 to produce two-thirds of the world's gold for many years. 

 The U.S.S.R. is thought to have a large part of the re- 



mainder, and no other country has more than a few percent 

 of the reserves. Official world gold currency reserves are 

 about 1.3 billion ounces, and a somewhat smaller amount is 

 hoarded; both reserves and hoards may become sources of 

 industrial gold, the first by government decision, the second 

 by a sufficient rise in the price of gold. 



United States nonmonetary consumption of gold has been 

 three to four times domestic production for several years, 

 and the United States is unlikely to become self-sufficient in 

 gold in the foreseeable future. United States gold reserves 

 of a few tens of millions of ounces are mainly in the Home- 

 stake (S. Dak.) and Carlin and Cortez (Nev.) gold deposits 

 and in copper deposits, such as Bingham, Utah, which pro- 

 duce byproduct gold. U.S. gold resources are large but in 

 general very low grade, and most placer deposits pose in- 

 surmountable technologic problems at present. Deposits as 

 yet undiscovered that are most likely to provide new gold 

 production are those of disseminated gold, similar to Carlin 

 and Cortez, which were overlooked in early prospecting. 



INTRODUCTION 



Gold is a yellow metal that has a density of 19.3 

 grams per cubic centimeter (nearly twice that of 

 lead and exceeded only by some of the platinum 

 metals and rhenium) and that is soft, very malleable 

 and easily shaped, and highly resistant to corrosion 

 and tarnish. Because of its workability, beauty, dura- 

 bility, and common occurrence as native metal, gold 

 was one of the first metals used by man. Over the 

 centuries it has been a principal medium of interna- 

 tional monetary exchange, and its physical proper- 

 ties have made it prized for jewelry and other adorn- 

 ments. Gold has traditionally been equated with 

 wealth, and the lore of lost gold mines and hidden 

 pirate hoards cannot be matched by that of any 

 other commodity. Even today gold is sought by the 

 weekend prospector in the hope of striking it rich, 

 as a very few of his predecessors did a century ago. 



Gold is known to have been mined in substantial 

 amounts for at least 6,000 years, probably first in 

 Egypt, where gold objects appeared as early as 4,000 

 B.C. (Sutherland, 1960, p. 25). Various estimates of 

 the amount of gold mined since the discovery of 



U.S. GEOL. SURVEY PROF. PAPER 820 



263 



