300 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1916. 



In earlier pages, the point was emphasized that the crux of the 

 present situation lies in the Mesabi Range of Minnesota. Of the 

 55.1 million tons produced in 1912, 32.6 millions came from it. The 

 chief point of immediate interest, therefore, is concerned with the 

 life of the Mesabi. Its decline means great rearrangements in the 

 present situation in the iron industry. The most recent estimates are 

 those of C. R. Van Hise, C. K. Leith, and W. J. Mead, in cooper- 

 ation, as given in Monograph 52 of the United States Geological 

 Survey, 1911. Fifty per cent of iron in the dried ore is assumed as 

 the minimum average yield at the time the estimates were made; 

 1,600 millions of tons were then credited to the Mesabi (p. 489) . The 

 output for 1910, for this range, was 30.57 millions, indicating a life 

 of a little over 50 years. At the production of 32.6 millions for 

 1912, a life of almost exactly 50 years is shown. If, on the other 

 hand, a minimum percentage of 35 in iron is considered, the same 

 authors assign to the Mesabi Range reserves of 30,000 million tons 

 (p. 492), which would give us 300 years of life, even at 100 million 

 tons annual output. 



The authors of Monograph 52 also discuss the reserves of the en- 

 tire Lake Superior region. The reserves of 50 per cent ore, in the 

 other ranges than the Mesabi, are less than one sixth its amount, and 

 their combined output about two-fifths its total. Their estimated life 

 is thus much shorter. The time period lies between 20 and 25 years. 

 When, however, we consider a minimum yield of 35 per cent, their 

 combined reserves are greater than those of the Mesabi, and are 

 estimated at 37,630 millions of tons. If we credit them with two to 

 three times their present annual output, a life of fully 1,000 years 

 is shown. 



Thus one can attack the problem from various points of view, 

 and with varying assumptions; but the conclusion is inevitable that 

 the output of ore from the Lake Superior region can not be kept 

 up at the present production and with a minimum yield of 50 per 

 cent for as much as 50 years, unless unanticipated new discoveries of 

 rich ore are made. With diminishing yield, however, and with the 

 tenor still at percentages above 35, the shipments of iron ore, even 

 in increasing amounts, can be maintained for centuries. 



Let us turn next to Alabama and its closely related States, Georgia 

 and Tennessee; since, together, they constitute the second center of 

 ore production. The great reserves lie in the Clinton ores, which 

 are well stratified and which have been and will be explored by bore 

 holes. The reserves are much increased by the brown ores of the 

 region and of northwestern Alabama, and by the probable devel- 

 opment of much older gray and red hematites in eastera Alabama; 

 but attention will be alone directed at this point to the Clinton ores. 

 The latter are so well stratified and persistent and are now proved 



