LEAD 



325 



nized, however, that the temperatures diminished 

 with time and that some copper-zinc-lead deposits 

 in contact zones are hydrothermal rather than pneu- 

 matolytic in origin. 



RESOURCES 

 RESERVES 



The reserves of lead contained in ores in known 

 mines and districts in the world are here estimated 

 to be about 141 million short tons, the equivalent 

 of a 31-year supply at the 1971 rate of consumption, 

 or a 22-year supply, not including recycled scrap, 

 if an average annual increase in consumption of 3 

 percent is assumed. 



These reserves are found on all of the continents 

 except Antarctica, occurring in more than 40 coun- 

 tries, as shown in table 65. The greatest concentra- 

 tion of lead reserves is in the Southeast Missouri 

 lead district; Weigel (1965, p. 77) estimates a 

 potential of 30 million tons of contained lead for 

 the Viburnum area alone. Other areas containing 

 significant concentrations include south-central Brit- 

 ish Columbia and east-central New Brunswick in 

 Canada, central Mexico, central Peru, the Balkan 

 nations in Europe, the Kazakhstan and Trans- 

 Baikal areas, U.S.S.R., and in particular, central, 

 north-central, and other parts of Australia. 



The estimate of reserves presented in table 65 

 compares with an estimate of 50 million tons of 

 measured and indicated ore and a possibly equiva- 



lent amount of inferred ore made a decade ago by 

 Callaway (1962, p. 2). The difference between the 

 two figures possibly reflects in part a more conser- 

 vative approach by the U.S. Bureau of Mines as 

 compared with the Geological Survey, but it should 

 be noted that Callaway's data preceded the discovery 

 and development of enormous lead deposits in south- 

 east Missouri, north-central Australia, Roumania, 

 and elsewhere during the past 10 years. Recent 

 unpublished Bureau of Mines estimates of the 

 measured and indicated reserves of lead in the 

 world are much closer to the estimates presented 

 here. 



The data presented in table 65 have been assem- 

 bled chiefly from such sources as: Published esti- 

 mates of tonnage and grade of ore reserves of spe- 

 cific mines and districts, which were based originally 

 on physical exploration and geologically permissive 

 extensions of known ore bodies, estimates made from 

 narrative descriptions of the general size, charac- 

 ter, and grade of less well developed deposits, and 

 10-, 20-, or 30-year projections of production data 

 from long-term lead-producing countries for which 

 specific reserve data or mine descriptions are not 

 available. The validity and accuracy of these data 

 are thus contingent upon a number of factors, in- 

 cluding : The degree to which some ore bodies, par- 

 ticularly those of the irregular limestone replace- 

 ment type, are accurately delineated more than a 

 few years in advance of mining; the extent of cur- 

 rent knowledge of the geology and ore habits within 



North America: 

 Canada : 

 Yukon 



Northwest Territories - 



British Columbia 



Saskatchewan-Manitoba 



Ontario 



New Brunswick 



Newfoundland 



other 



Total, Canada 



Table 65. — Estimate of world reserves ' of lead, by regions or countries 



[In thousands of short tons] 



United States: 



Northeast Washington 



Coeur d'Alene district 



Butte district 



Great Basin 



Rocky Mountains 



Tri-State 



Southeast Missouri 



Upper Mississippi Valley 



Kentucky-Illinois 



East Tennessee 



Austinville district 



Northern New York 



Appalachian Massive: 



Sulfide Belt 



other 



3,BO0 



1,250 



5,000 



200 



400 



4,500 



300 



700 



16,860 



150 

 1,600 



500 

 2,500 

 1,000 



260 

 30,000 

 1,000 



Total. United States 39,185 



Greenland TO 



Total, North America 64,106 



Central America; 



Mexico 



Honduras 



other 



Total, Central America 



Brazil - - 

 Chile ... 

 Colombia 

 Peru 



Total, South America 



Europe: 



Austria 



Bulgaria 



East Germany 



Finland 



France 



Greece 



Ireland 



Italy 



Norway 



Poland 



Rumania 



Spain 



Sweden 



West Germany 



Yugoslavia 



Other 



4.500 

 250 

 100 



1,000 

 800 

 750 

 100 



175 



3.500 



500 



100 



700 



300 



2,000 



1,000 



100 



2,600 



500 



2,750 



2,500 



4,60<) 



3,000 



600 



Total, Europe 24,626 



Africa : 



Algeria 



Morocco 



South West Africa 



Tanzania 



Tunisia 



Total, Africa 



Asia: 



Burma 



China 



India 



Iran 



Japan 



North Korea 



Russia (U.S.S.R.) 



South Korea 



Thailand 



Turkey 



Total, Asia 



7B0 

 1,500 

 1,600 

 100 

 400 

 760 

 200 



6,200 



760 

 3,000 



126 

 2,000 

 1.200 

 1,800 

 18,000 



600 

 20 



100 



World total .._ 140,960 



^ Reserves : Identified deposits from which minerals can be extracted profitably with existing technology and under present economic conditions. 



