•76 JOHN BIRKINBINE 



leased properties after having been explored or developed 

 are sublet, and thus two or more royalties may be cumulative. 

 A deposit of ore has no definite value to the lessee or sub- 

 lessee, other than what he gets out of it during the term of his 

 lease, for he has no interest in its future and the owner can 

 practically base no estimate of value except by capitalizing 

 its earning capacity, providing that earning capacity can be 

 maintained. Another feature which has caused trouble in an 

 attempt to determine approximate valuations for the iron ore 

 deposits of the United States has been that a company may 

 own or lease a considerable tract of land only a small part of 

 which has been explored or exploited. It would be mani- 

 festly unfair to base an estimate of the value of the entire 

 property upon results obtained from a limited area. 



All of the ore mined in the United States is not utilized 

 in the production of metal for steel manufacture, for in this 

 freedom from phosphorus is generally necessary; an excess of 

 this element, however, is admissible in iron treated by the 

 basic Bessemer process. 



For use in foundries, for treatment in puddling furnaces, 

 and for other purposes which, taken together, consume ap- 

 proximately one quarter of the pig iron produced, the limita- 

 tions as to phosphorus are less rigid. For these purposes many 

 ores may be smelted which are not considered desirable in 

 manufacturing pig iron for conversion into steel. However, 

 other elements than phosphorus demand consideration, and 

 in the selection of ores their chemical composition determines 

 their availability for specific use. The percentage of iron 

 which an ore yields is the first consideration, for upon this the 

 economy of smelting primarily depends, but objectionable 

 elements or oxides may encourage the selection of an ore con- 

 taining less metallic iron, but freer from objectionable con- 

 stituents than an ore with high iron contents associated with 

 deleterious ingredients. 



Iron ore deposits in the United States vary materially in 

 character, size, and occurrence, and the geological and physical 

 conditions of the several varieties generally known as mag- 

 netite, red hematite, brown hematite, and carbonate ores re- 

 quire different methods of exploitation which also vary greatly. 



