614 



UNITED STATES MINERAL RESOURCES 



Table 127. — Sulfur resources of Canada and Mexico 

 [In millions of Ions: tons] 



^ 



Canada 



Mexico 



Hypothe- 

 tical 3 and 

 Identified Bpecula- 



resources ^ tive 3 re- 

 sources 



Hypothe- 

 tical ^ and 

 specula- 

 Identified tive 3 re- 

 resources * sources 



1. Elemental sulfur deposits in evaporites . 



2. Hydrogen sulfide in sour natural gas __. 



3. Organic sulfur in petroleum 



4. Pyrite deposits 



5. Elemental sulfur in volcanic rocks 



6. Sulfur contained in metallic sulfides 



7. Gypsum 



8. Organic sulfur in tar sands 



9. Organic sulfur and pyrites in coal 



0. Organic sulfur in oil shale and shale rich 



in organic matter 



140 



5 



= 25 



"35 



C) 

 40 

 (') 



(•) 



185 

 (') 

 25 



"ioo 



(") 



1,800 



(') 



(•) 



325 

 5 



50 



"135 



I'sio 



80 



'"5 



'25 



5 



25 



(•) 



50 

 25 



"io 



(') 



130 



50 



5 



65 



Total 



245 



2,110 



2,355 



115 



255 



^Identified resources: Specific, identified mineral deposits that may or may not be evaluated 

 may or may not be profitably recoverable with existing technology and economic conditions. 



to extent and grade, and whose contained minerals 



'Hypothetical resources: Undiscovered mineral deposits, whether of recoverabli 

 in known districts. 



3 Speculative resources ; Undiscovered mineral deposits, whether of reco verable 

 unrecognized or unconventional form. 



* Not known: resources probably small. 



^ Including pyrite in base-metal deposits. 



^ Not known: resources probably large. 



sbueconomic grade, that are geologically predictable 



subeconomic grade, that may exist 



unknown districts 



f .o.b. gulf coast ports ; (2) paramarginal, those avail- 

 able at prices between $25 and $35; and (3) sub- 

 marginal, those estimated to be available at prices 

 higher than $35 per ton. Hypothetical and specula- 

 tive resources are comparable to those are defined 

 throughout this volume. Comments on each of the 

 principal accumulations follow. 

 1. Identified resources of elemental sulfur in 

 evaporites cannot be estimated accurately be- 

 cause operating companies do not release reserve 

 data. It is judged, however, that some 200 mil- 

 lion tons of sulfur remains in the known de- 

 posits, 100 million tons each in the gulf coast 

 and in the west Texas occurrences. Of the total 

 of 200 million tons, some 40 million tons is 

 thought to be minable only when the price of 

 sulfur approaches $35 a ton, and another 10 

 million tons is thought to be minable only when 

 the price exceeds $35 a ton. Another 100 million 

 tons of sulfur, which may be found in west 

 Texas, is shown in table 126 as part of hypo- 

 thetical resources. 



In the United States, anhydrite occurs in 

 many petroliferous sedimentary basins, includ- 

 ing the Michigan, Williston, Paradox, and Per- 

 mian basins; anhydrite also occurs at great 

 depths in the gulf coast geosyncline. Elemental 

 sulfur deposits could have formed in all or any 

 of these areas, and one can speculate that at 

 least 100 million tons of sulfur ultimately will 

 be discovered in them. 



The possibilities for further discovery of ele- 

 mental sulfur deposits in anhydrite caprocks 



overlying salt diapirs are somewhat more lim- 

 ited because of the diverse geological processes 

 and conditions required in their generation. Salt 

 diapirs are common structures known on all 

 continents and continental shelves in many parts 

 of the world (McKelvey and Wang, 1970) , yet 

 only in the gulf coast of the United States and 

 Mexico have deposits of commercial size been 

 found in caprocks. It can be anticipated that 

 several more sulfur deposits, containing per- 

 haps 50 million tons of sulfur, will be found in 

 the offshore extension of the gulf coast belt of 

 the United States. 



Hydrogen sulfide in natural gas yielded about 

 30,000 tons of sulfur per trillion cubic feet of 

 produced gas in 1971. Using this ratio, some 

 15 million tons of sulfur is estimated to remain 

 in the identified resources of natural gas (Theo- 

 bald and others, 1972). Another 65 million 

 tons may occur in recoverable undiscovered 

 resources, and 120 million tons, in the sub- 

 marginal undiscovered resources (combined as 

 185 tons of hypothetical resources in table 126) . 

 Each billion barrels of petroleum in the United 

 States reserve contains nearly 1 million tons of 

 sulfur (U.S. Bur. Mines, 1971), a ratio which 

 indicates that some 10 million tons of sulfur is 

 contained in the recoverable petroleum and 245 

 million tons in the petroleum that can only be 

 extracted with diflSculty. Another 1 billion tons 

 of sulfur may occur in the undiscovered petro- 

 leum resoruces, of which 20 percent is a recov- 

 erable resource and 80 percent is a subeconomic 



