IRON ORES: BROWN ORE. 13 



The main dependence of the furnaces of the Birmingham 

 district is the hard ore. In the mines it always sets in at the 

 water level, holding its own as to thickness and composition, 

 to the bottom of the deepest mine, 1850 feet, and as far as 

 tested by borings, at least 3,500 to 4,000 feet to the southeast 

 from the outcrop; there seems thus to be no reason for antic- 

 ipating any adverse change in the ore within the depth to 

 which mining operations are likely to be carried. 



When the hard ore carries about equal amounts of silica 

 and lime it is self-fluxing, and under these conditions it has 

 been used alone in the furnaces. Usually, however, it con- 

 tains more lime than is necessary for self-fluxing, in which 

 case, a little soft ore, or brown ore, or both are added. 



At the present time the soft ore makes seldom over ten per 

 cent of the ore burden, though in some of the furnaces it 

 makes half of the burden. From stock house samples the 

 composition of the hard ore is shown to be about as follows : 

 Silica, 13.4 per cent.; Metallic iron, 37 per cent.; Lime, 16.20 

 per cent.; Alumina, 3.18 per cent.; Phosphorus, .37 per cent.; 

 Sulphur, .07 per cent.; Carbonic acid, 12.24 per cent.; Water, 

 0.50 per cent. 



Red Hematite occurs in Alabama also in the Trenton for- 

 mation, where it is very similar in quality and appearance 

 to the soft red ore of the Clinton. And in the Cambrian for- 

 mation still lower in the geological column, it has been ob- 

 served in stratified seams from 18 inches to 5 feet in thick- 

 ness. 



The Cambrian ore is of the crystallized or specular variety, 

 and may some day be utilized. The known occurrences of 

 it are few in number and none of them has as yet been fully 

 tested. 



(2.) BROWN ORE OR LIMONITE. - - This ore, the sec- 

 ond in importance of the iron ores of Alabama as well as of 

 the United States, furnished only 9.3 per cent of the total iron 

 ore production of the United States in 1902. Of this, Alabama 

 produced 28 per cent, 1,008,839 long tons, and the state kads 

 in this industry. 



In the early days of iron making and up to the year 1876 

 this was the only ore used in the Catalan forges, bloomaries, 

 and charcoal furnaces of the state. It was then demonstrated 

 4 



