DISTILLATION OF STUMPWOOD. 



55 



quantity of turpentine, the change in market conditions makes it 

 desirable to throw as much of it into the pine-oil fraction as is 

 possible, or to go a step farther and market the entire crude dis- 

 tillate as flotation oil. If this were done it would, of course, re- 

 duce decidedly the cost of running the plant, and simplify opera- 

 tion. The consequent reduction in cost of production would prob- 

 ably amount to $2 or $3 a cord. 



As to future flotation-oil values it is difficult to conjecture. The 

 Bureau of Mines, which experimented with the various oils obtained 

 in the course of this work, commenting on the conditions that will 

 probably have to be met in the flotation-oils market during the 

 coming years, points out that : 



Pine oil at 50 to 60 cents per gallon has cost too much. Crude petroleum 

 and coal tar containing small additions of pine oil can be made to do almost 

 the same grade of work and are hence cheapening the cost of flotation oils. 

 Pine cresote, pine tar oils, and various hardwood fractions, together with 

 hardwood tar, are finding acceptance in place of the more expensive products. 

 There will always be a market for pine products, however, as long as they 

 do not cost too much; 30 to 40 cents per gallon, f. o. b. the West, will probably 

 be the price paid for such material and when the price goes much above that, 

 the material will merely be eliminated from consideration. 



Some idea of the quantities of these pine products used in the flota- 

 tion of ores may be obtained from Table 20. 



TABLE 20. Monthly consumption of flotation oils in the United States (1916). 

 [Compiled from a report of the Bureau of Mines.] 



1 Probably includes a considerable amount of the lighter fractions of pine-tar oil. 



2 The crude light oil would probably come in this class. 



3 The crude heavy oil would probably come in this class. 



It has been pointed out that combinations of different oils are 

 used by mixing the more expensive pine- wood distillates with crude 

 petroleum, coal tar, etc., in suitable proportions to obtain the de- 

 sired foaming and collecting effect for the kind of ore to be treated. 

 While this is to a large extent done at concentration plants, some pro- 

 ducers in the East market blended oils on this same principle. This 

 should, of course, be given careful consideration by those-who may 



