THE BARITE DEPOSITS OF MISSOURI 103 



distances were less and two loads a day could be hauled, the rate 

 was $1.50 to $1.75 and then the miner got more per ton as a re- 

 sult. The average price per ton for Missouri barite is estimated 

 at $6.27 by the U. S. Geological Survey. 



Royalties run from 50 cents to $1.00 per ton. A consider- 

 able amount of "grandmaing" is done in some places. This is 

 the local term applied when the miners work on property for 

 which they are not paying a royalty. The most common practice 

 is to pay so much a ton for mining and cleaning the barite. 



At the railroad, the barite is either shoveled into cars or 

 piled on stock platforms. The miners near Mineral Point haul 

 their product to the mill at that town. 



Treatment at the Point Milling and Manufacturing Com- 

 pany's Mill. — The barite is first crushed to one-inch mesh and is 

 then passed thru an automatic washer (on the plan of a log 

 washer) in which the clay is removed. The material then passes 

 thru screens, the coarser going to the granite grinders and the 

 finer to tube mills. From there the material passes thru a classi- 

 fier, the oversized pieces going back to the tube mill, and the un- 

 dersized ones, that pass thru a 200-mesh screen, going to settling 

 tanks where the excess water is removed. The sludge is then 

 placed in lead-lined tanks and treated with sulfuric acid at a tem- 

 perature of 212° F. to remove the iron stain which is always pres- 

 ent on the barite that comes from the clay. The finely ground 

 barite is then washed to remove the acid and then passes to the 

 dryer and on to the packer. It is shipped in barrels and sacks. 

 An ordinary flour barrel full of barite weighs about 700 pounds. 



Uses. — Barite has a very large variety of uses. In recent 

 years, it has been coming into its own in various fields, as it was 

 first necessary to overcome the belief that it was used as an 

 adulterant. It was formerly thot to have been used not only in 

 paints as a substitute for white lead and zinc oxide, but also as 

 an adulterant in foods of various kinds. This belief has not yet 

 been entirely eradicated. The series of experiments carried out 

 by the scientific section of the Paint Manufacturers'. Association 

 of the United States, and the Institute of Industrial Research, 

 proved that mixtures of white lead and zinc oxides with as much 

 as 15 per cent of inert crystalline pigments, such as barite, silica. 



