MERCURY 



409 



metacinnabar occur in thick carbonate veins. The 

 largest ore shoot in shale was 300 feet long, 25- 

 150 feet wide, and 800 feet high. Ore mined in the 

 early days contained 10 percent cinnabar, but for 

 the past 30 years, mined ore has averaged less than 

 1 percent. 



These deposits have in common cinnabar as the 

 major ore mineral and comparatively shallow depth, 

 but little else. Some are in sedimentary rocks such 

 as limestone, quartzite, or shale, and some are in 

 volcanic breccia or altered serpentine. Some major 

 ore bodies have been formed by replacement, others 

 by open-space filling, and others by both, and some 

 are a result of detrital concentration. The thousand 

 or so smaller deposits not described in this report 

 likewise show a diversity of mineralization, host 

 rocks, rock alteration, and structural localization. 



RESOURCES 



IDENTIFIED RESOURCES 



At most mercury mines, no effort has been made 

 to ascertain the ultimate reserve of the deposit in 

 advance of exploitation, and at few mines is enough 

 ore blocked out for more than 1 year of operation. 

 Major exceptions are at some of the larger foreign 

 deposits, such as Almaden or Idria, but even at these 

 no attempt is made to learn in advance the complete 

 resource. In the Soviet Union, much effort is ex- 

 pended in trying to determine the ultimate reserves 

 before mining, with only indifferent success for 

 mercury deposits, but all reserve figures are closely 

 guarded. Hence, no one knows the total reserves or 

 resources of the major mercury deposits of the 

 world, and only estimates based on production rec- 

 ords and familiarity with the geologic habits of the 

 ore can be made. On this basis, we have estimated 

 the resources of known areas by countries or by 

 groups of countries (table 82). 



Table 82. — Identified mercury resources of the world ' 

 [Given in thousands of flasks in ore minable at price per flask indicated] 



$400 $1,000 



United States 170 490 



Canada 200 400 



Mexico 300 700 



South America 50 300 



Spain 2,500 6,000 



Italy 750 2,000 



Yugoslavia 1,000 2,000 



Czechoslovakia 15 30 



Africa 30 60 



Japan 60 200 



Turkey 60 200 



Philippines 50 200 



U.S.S.R. 1,000 3,000 



Communist China 1,000 1,500 



Total 7,185 17,080 



^ Identified resources : Specific, identified mineral deposits that may or 

 may not be evaluated as to extent and grade, and whose contained minerals 

 may or may not be profitably recoverable with existing technology and 

 economic conditions. 



Estimates by States, made on a similar basis but 

 with greater familiarity with the deposits, are given 

 in table 83. 



Table 83. — Identified mercury resources of the United States, 

 by States ' 



[Given in thousands of flasks in ore minable at price per flask indicated] 



$400 $1,000 



Alaska 25 100 



Arizona 1 6 



Arkansas — 1 



California 100 300 



Idaho 10 25 



Nevada 20 30 



New York 5 5 



Oregon 5 10 



Texas 4 10 



Utah — 1 



Washington — 2 



Total 170 490 



^ Identified resources : Specific, identified mineral deposits that may or 

 may not be evaluated as to extent and grade, and whose contained minerals 

 may or may not be profitably recoverable with existing technology and 

 economic conditions. 



A word of caution seems required in the use of 

 these numbers, especially those for the United 

 States. Although these estimates are for ore in 

 known ore-bearing areas, they do not represent 

 known ore. At $400 a flask, even if the ore were 

 minable once it had been found, the cost of finding 

 it might be excessive. Thus, while U.S. mines offer 

 a potential at this price, few will be reopened or 

 explored by other means until the price is higher or 

 is expected to go higher. For other estimates of 

 resources at various prices, see U.S. Bureau of Mines 

 (1965). 



SPECULATIVE RESOURCES 



Masses of rock containing concentrations of mer- 

 cury rich enough and large enough to form minable, 

 or even near-minable, ore deposits are exceedingly 

 rare. The surface area underlain by known mercury 

 ore throughout the world probably does not exceed 

 50 square kilometers, which is about one three- 

 millionth, or 0.00003 percent, of the earth's land 

 area. In considering the mercury potential of the 

 world, or in the search for new mineralized areas, 

 the economic geologist concerns himself with the 

 question of what parts of the remaining 99.99997 

 percent might be underlain by mercury ore. We ex- 

 pect we are searching for places comparable in size 

 to known ore bodies, which in proportion are even 

 smaller than the proverbial needle in a haystack. 

 Origin and geologic occurrence of known deposits 

 provide the best clues about where to look and the 

 best data for predicting the potential of unexplored 

 areas. 



During the past century, geologists noting the 

 global distribution of mercury deposits about the 

 Pacific, with a branch extending westward from 



