14 MINERAL RESOURCES OF ALABAMA. 



that good iron could be made at low cost from the red ores, 

 with coke for the fuel. 



In general the limonites are considered the best of the ores 

 of Alabama and they command the highest prices and com- 

 mand a ready sale. 



The usual mode of occurrence is in irregular masses of con- 

 cretionary origin in the residual clays resulting from the de- 

 composition of limestones, and as a consequence the mining 

 is uncertain and expensive. Limonite also occurs in regular- 

 ly stratified seams or beds, and then it is the result of the al- 

 teration of pyrites or of carbonate ores. Practically all of the 

 brown ore actually mined is that occurring in the residual clays 

 above mentioned. Most of the ore before going to the fur- 

 nace is washed and screened, and this manipulation, together 

 with the cost of mining, makes it the most expensive of the 

 iron ores, and it is therefore seldom used alone, but is usually 

 mixed with the red ore in proportions determined by the 

 quality of the iron desired. It is used alone in the charcoal 

 furnaces and also in the coke furnaces when a particularly 

 tough pig iron is wanted. Usually the brown ore constitutes 

 about 20 per cent of the ore burden. This addition of brown 

 ore to the red, besides taking care of the excess of lime in the 

 hard red ore, causes a smoother and more uniform flow in the 

 furnace burden, lessening the danger from hanging or shelv- 

 ing. 



In a few places a manganiferous limonite occurs, and small 

 quantities of it have been used in the production of spiegel- 

 eisen, and ferro-manganese. 



The limonite deposits are very numerous and are distrib- 

 uted over a broad expanse of country and in many places are 

 known to be very extensive. In some of the deposits the ore 

 is in nearly solid mass, in others it is much scattered, and in 

 consequence the amount of foreign material necessary to be 

 moved for every ton of ore produced, varies very much, not 

 only in the different ore banks but also in the different parts 

 of the same bank. The mining is in irregular diggings and 

 open cuts, and is mostly done by contract, costing about 75 

 cents on an average to mine, and bringing about $1.00 per ton 

 at the furnace 



Among the varieties of brown ore are the compact, the honey 

 comb, and the ochreous or earthy ores. The pocket ore is 



